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April, 2015
Bellingen Shire Estuary Inundation MappingFinal Report
www.bmtwbm.com.au
K:\n20222_Bellingen_EstuarySLR\docs\R.N20222.001.02.docx
Bellingen Shire Estuary Inundation Mapping Bellingen Shire Estuary Inundation Mapping Bellingen Shire Estuary Inundation Mapping
Prepared for: Bellingen Shire Council
Prepared by: BMT WBM Pty Ltd (Member of the BMT group of companies)
Offices Brisbane Denver London Mackay Melbourne Newcastle Perth Sydney Vancouver
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Document Control Sheet
BMT WBM Pty Ltd 126 Belford Street Broadmeadow NSW 2292 Australia PO Box 266 Broadmeadow NSW 2292 Tel: +61 2 4940 8882 Fax: +61 2 4940 8887 ABN 54 010 830 421 www.bmtwbm.com.au
Document: R.N20222.001.02.docx
Title: Bellingen Shire Estuary Inundation Mapping
Project Manager: Luke Kidd
Author: Luke Kidd, Rohan Hudson, Suanne Richards, Paul Donaldson
Client: Bellingen Shire Council
Client Contact: Daan Schiebaan
Client Reference:
Synopsis: This document outlines Sea Level Rise Mapping undertaken for the Bellingen Shire Estuary which includes an estuary inundation risk assessment for present and future timeframes of 2050 and 2100. A register of the level of risks to various land and assets within the study area and suggested potential mitigation options to reduce the level of future risk due to SLR is also provided.
REVISION/CHECKING HISTORY
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9 Oct 2014 1 April 2015
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DISTRIBUTION
Destination Revision
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Bellingen Shire Council
BMT WBM File
BMT WBM Library
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Acknowledgement BMT WBM Pty Ltd (Member of the BMT group of companies) has prepared this document for Bellingen Shire Council with financial assistance from the NSW Government through its Estuary Management Program. This document does not necessarily represent the opinions of the NSW Government or the Office of Environment and Heritage.
Bellingen Shire Estuary Inundation Mapping i Executive Summary
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Executive Summary
The Bellingen Shire Estuary Inundation Mapping Study describes tidal inundation extents for both typical
ocean conditions and severe storm events under existing and future mean sea level conditions. The maps
and suggested mitigation options produced as part of the project can be used by Bellingen Shire Council
(BSC) in preparation for and adaptation to rising sea levels. With appropriate planning, social disruption,
economic loss and environmental impacts can be minimised.
This study complements the Bellingen Coastal Zone Hazard Study (CZMS) and Management Plan (CZMP)
which defined the present and future coastal hazards for the Bellingen study area in accordance with the
NSW Coastal Protection Act, 1979 and associated Guidelines for Preparing Coastal Zone Management
Plans (OEH, 2013). A risk based assessment was undertaken of the predicted sea level rise inundation
hazard and their consequences. By utilising the same methodology, the outcomes of this study can be easily
integrated within the CZMP at a later stage.
Study Area
The Bellingen Shire Local Government Area (LGA) is located on the NSW Mid North Coast and includes
some 15 km of coastline extending from Oyster Creek in the south to Tuckers Rocks in the north.
Three notable coastal entrances are situated along the Bellingen coastline, namely Oyster Creek and
Dalhousie Creek (which are small creeks intermittently open to the ocean) and the larger Bellinger / Kalang
River with its partially trained entrance at Urunga.
The floodplains of the Kalang and Bellinger Rivers between Urunga and Mylestom are low-lying and subject
to the potential inundation impacts of climate change and sea level rise. The potential impact to both private
and public land as well as assets within the BSC LGA is significant.
Study Objectives
The objective of the study is to systematically and comprehensively identify the extent of sea level rise risks
facing the BSC LGA by determining the flood levels for immediate and future sea level rise scenarios. Using
model results including the estuarine inundation depth and extent, the study seeks to identify the areas of
current and future tidal inundation and assess the risk to infrastructure (built environment) and ecological
assets within the Bellinger-Kalang Estuary.
Estuary Inundation Modelling
The impact of sea level rise on areas was assessed by modelling a range of design tidal inundation events
on the three estuaries located in the LGA, namely the Bellinger-Kalang Estuary, Dalhousie Creek and Oyster
Creek. An existing TUFLOW flood model of the Bellinger and Kalang River was reviewed and updated to
determine design tidal inundation levels and extents for current and future sea level rise conditions. For the
smaller Dalhousie Creek and Oyster Creeks ICOLLs, a bathtub modelling approach was used to determine
design tidal inundation extents.
Estuary inundation modelling is presented for twenty (20) design runs including four (4) design events (spring
tide; king tide; 20-year Average Recurrence Interval; and 100-year Average Recurrence Interval) for five (5)
different sea level rise scenarios (i.e. 0.0 metres, +0.4 metres, +0.7 metres, +0.9 metres and +1.4 metres
Bellingen Shire Estuary Inundation Mapping ii Executive Summary
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above Australian Height Datum (m AHD). Maps showing the approximate inundation extent for key localities
in the study area are provided in Appendix B.
Estuary Ecological Modelling
In order to better understand the ecological impact(s) of sea level rise, statistics of longer term water level
and salinity variations were obtained by developing a new estuary (hydrodynamic) model capable of
simulating a continuous period of estuary hydrodynamics (water levels and salinity concentration). In addition
to the estuary model, a catchment (hydrologic) model was required to estimate freshwater inputs to the
estuary which influence the water levels and longitudinal salinity variations along the Bellinger and Kalang
Rivers.
Comparing between sea level rise scenarios, the modelling demonstrates that 10 km upstream of the
entrance (Bellinger River at Raleigh and Kalang River near Newry Island), and with a sea level rise of
1.4 metres, the median water level would be notably greater (approximately 0.3 metres) than the maximum
water level expected under existing tidal conditions. Of somewhat more importance, the minimum water level
at that same location and sea level rise is 1 metre higher than the lowest water level estimated for the
existing (without sea level rise) condition. A water level of this magnitude would only be exceeded about 5%
of the time under existing conditions, which typically occurs during large spring or king tides.
Scenario modelling shows that low salinity is controlled by large fluvial flow events from the upstream
catchment, which can maintain freshwater conditions along the full length of the two river systems down to
the estuary mouth. The relative position of minimum salinity along the two rivers is comparable between the
different sea level rise scenarios. However, the change in the relative position and slope of the longitudinal
salinity profiles between the different scenarios shows that the ingress of saltwater will increase with sea
level rise, more so along the Kalang River than the Bellinger River, which is partly due to the smaller
catchment area and lower river discharge occurring along that reach of the estuary.
Risk Assessment Methods
A risk based approach was applied to this study, to guide the development of management options. Risk is
defined as the combination of ‘likelihood’ and ‘consequence’ for an event. The study defines various
‘likelihood’ scenarios for estuary inundation, for present day and future (2050 and 2100) timeframes. A key
component of this study was to determine ‘consequence’ of inundation caused by sea level rise on the
affected land and assets.
The sea level rise inundation hazard consequence was guided by the outcomes of a formal Risk Assessment
Workshop conducted during the preparation of the CZMP, professional judgement and local knowledge of
the study area.
The level of risk to specific land and assets was derived from the combination of the ‘consequence’ assigned
to land / assets and the ‘likelihood’ of the hazards. The level of risk was tabulated as a risk register for
important assets. ‘High’ and ‘extreme’ risk levels are considered to be intolerable, whereas ‘medium’ and
’low’ levels of risk are defined as tolerable and acceptable, respectively.
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Risk Assessment Outcomes
From the risk assessment process, the assets and land found to have intolerable levels of risk under the
present and future (2050 and 2100) timeframes were identified and subsequently prioritised for
management.
Significant occurrences of residential, rural, primary production and recreation also experiencing intolerable
levels of risk under present and future timeframes may occur. Forestry, primary production and rural land is
typically at risk at many of the suburbs and most susceptible to potential sea level rise inundation due to its
proximity to the main estuary waterways. At some localities such as Bellingen and Raleigh, low-lying sewer
and stormwater services (i.e. rising main and drainage main and waste management centre) are at high risk.
The suburbs of Mylestom, Repton and Bellingen may experience the smallest inundation impact for the
immediate, 2050 and 2100 timeframes with the vast majority of asset categories not at risk. Residential
development at Urunga may be at risk under future scenarios compared to the immediate timeframe. At all
other suburbs, residential development is not at risk from sea level rise inundation for the immediate and
2050 timeframes although a medium risk is calculated at Raleigh for the 2100 timeframe.
Significant inundation of primary production land which is already at risk for the immediate timeframe may
increase further as a consequence of projected sea level rise for the 2050 and 2100 timeframes. Throughout
the study area, there is a variety of natural assets including Endangered Ecological Communities (EEC) of
coastal saltmarsh, freshwater wetland, littoral rainforest, lowland rainforest, subtropical coastal floodplain
forest and swamp sclerophyll forest. Ecological communities are by far at the greatest risk, particularly at
Urunga Lagoon where the largest continuous area of coastal saltmarsh is present.
Inundation Risk Management Approach
Defining risk levels at various timeframes has been used to appropriately develop and prioritise risk
management treatment options. Extreme and high risks that occur in the present day require management
immediately as a priority. For future extreme and high risks, it is more important to determine a reliable
‘trigger’ for action. The trigger must be set to enable enough time to gain approvals, raise funds and
implement the action, prior to the hazard impact occurring.
While the exact option for managing the future risks may not need to be refined now, it is important to
determine the long-term management intent for assets at risk, for example, relocation, redesign, protection,
abandonment and so on. In the interim, until impacts become imminent, management actions that have
minimal adverse impacts and / or improve the ability to treat other risks in the future should be pursued.
These have been termed ‘No regrets’ actions.
Risk Management Options
Risk management options recommended for managing the mapped estuary inundation hazard are provided.
The options are collated based on the multi criteria analysis conducted in the Coastal Zone Management
Study (CZMS), and refined to suit the needs of the assets types in the context of Bellingen Shire. Detailed
descriptions of all management options are provided in Appendix E of the Bellingen CZMS (2014), although
those considered most suitable to the management of sea level rise inundation in the study area are
discussed, namely:
• Monitoring to collect better information regarding coastal processes and to determine when a risk is
approaching;
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• Asset Management Planning to incorporate the likelihood of the coastal hazards to impact upon
Council’s assets;
• Audit of Existing Council Assets to support the management of coastal hazards when assets are
replaced;
• Use of the existing flood policy as an interim measure to regulate inundation risks due to periodic ocean
events for future development and redevelopment of existing properties;
• Community Education in the format of ongoing updates to community regarding occurrence of climate
change, particularly sea level rise; and
• LEP Review and Rezoning to ensure that vacant land is not developed inappropriately particularly
where land that is known to be at risk from inundation.
In addition to the management options outlined above, the estuary inundation risk assessment may be used
to identify ecological communities that require priority Habitat Management and Rehabilitation. High Value
Natural Assets in the riparian corridor, floodplain and estuarine reaches of the Bellinger and Kalang River
estuaries are most at risk from rising sea levels. Given their limited distribution in a largely cleared
agricultural setting, and the poor condition of the riparian vegetation, these communities may require
management intervention to improve their resilience to increased inundation and in the case of tidal
wetlands, assist with habitat transition.
It is recommended that Council initially focus actions to address sea level rise within the extreme to high risk
locations and riparian reaches. Accordingly, eight sites are identified for ongoing monitoring of geomorphic
response and ecological community change, with site selection based on accessibility and the presence of
High Value Natural Assets likely to be impacted by sea level rise. Given the timeframes over which projected
sea level rise impacts may occur (2050 onwards), and the complicated interactions involved, Council will be
required to develop ongoing adaptive strategies to assess and manage sea level rise impacts. This will
require regular monitoring to map the distribution and condition of coastal habitats in association with any
observations of sea level rise.
Conclusion
Climate change and sea level rise have the ability to impact private and public land and assets within the
Bellingen LGA. The study has updated and made use of existing (and newly developed) computer models to
calculate tidal inundation in the main river estuary and Intermittently Closed and Open Lakes and Lagoons
(ICOLLs) present in the LGA. The study has determined the estuarine and coastal inundation extents for a
range of design ocean events and four epochs and associated mean sea levels, and identifies those areas
within the LGA that are likely to be impacted (negatively or otherwise) by sea level rise.
There are areas within the Bellinger-Kalang Estuary that may be impacted by more frequent tidal inundation
(exacerbated by sea level rise) including farmland and unsettled low-lying floodplain areas around Mylestom,
Repton and Fernmount. The Urunga Golf course and adjacent riverfront properties as well as some rural
properties located on Newry Island may also be impacted more frequently with sea level rise. Other areas
that are currently not impacted by tidal inundation but may begin to experience infrequent (i.e. 20-year and
100-year ARI events) include the broad floodplain area between Mylestom and Raleigh, and to the northwest
of Repton and Raleigh, low-lying areas to the west of Yellow Rock Road and to the east of the Pacific
Highway. Several rural, residential and primary production properties around the townships of Raleigh,
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Mylestom, Repton and Fernmount, and numerous rural, residential properties situated on Newry Island may
be affected. Likewise, properties in the Urunga Industrial precinct, near the Urunga Golf Course / tennis
courts and waterfront properties in the immediate vicinity of Urunga Lagoon may also be affected.
Due to the steep topography surrounding Dalhousie Creek and Oyster Creek ICOLLs, inundation extents are
largely confined to the main waterway and adjacent low-lying intertidal area. Private properties and other
infrastructure are not expected to experience any significant inundation during infrequent tidal inundation
events (i.e. with 20-year and 100-year ARIs) even with 1.4 metres of sea level rise.
In addition to properties and infrastructure, the study area also supports a range of High Value Natural
Assets, some of which are at risk from sea level rise. Based on the sea level rise projections adopted, it is
anticipated there may be increased inundation and saline intrusion into Coastal Saltmarsh and Swamp Oak
Forest communities in the lower and middle estuarine reaches. This may result in landward retreat of those
communities if habitat conditions are suitable as well as the expansion of mangroves landward and further
upstream with the tidal front. Potential inundation of floodplain wetland habitat is also anticipated for all
estuary reaches.
Provided conditions are suitable for colonisation, estuarine wetland habitats are expected to migrate
landward in response to a shift in the tidal planes. Some habitats, particularly Coastal Saltmarsh, are prone
to coastal squeeze which may prevent landward migration as sea levels rise. This is particularly evident in
the lower reaches of the Kalang River where existing Coastal Saltmarsh communities abut residential
development including roads. Due to natural migration, low-lying, flat areas above the tidal range, particularly
those that lie adjacent to existing vulnerable habitats, may become increasingly important to protect and
restore as potential areas for future habitat migration. This includes agricultural lands which have been
previously cleared. Priority areas for protection should also be located along tributaries and creeks. It is
therefore recommended that Council considers management measures (e.g. monitoring, weed control,
revegetation, water quality protection, fire management) that provide buffering, connectivity and migration of
vulnerable habitats, particularly Freshwater Wetlands, Coastal Saltmarsh, Swamp Oak Forest, Swamp
Sclerophyll Forest, Lowland Rainforest and riparian vegetation.
Bellingen Shire Estuary Inundation Mapping vi Glossary of Terms
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Glossary of Terms
100-year event An event that occurs on average once every 100 years. Also known as a 1% AEP event. See annual exceedance probability (AEP) and average recurrence interval (ARI).
20-year event An event that occurs on average once every 20 years. Also known as a
5% AEP event. See annual exceedance probability (AEP) and average recurrence interval (ARI).
Annual Exceedance Probability AEP (measured as a percentage) is a term used to describe the size of an
event. AEP is the long term probability between events of a certain magnitude. For example, a 1% AEP event is one that has a 1% probability of occurring in any given year. The AEP is closely related to the ARI.
Australian Height Datum A common national plane of level approximately equivalent to the height
above sea level. All water levels presented in this report have been provided in metres AHD.
Average Recurrence Interval ARI (measured in years) is a term used to describe event size. It is a
means of describing how likely an event is to occur in a given year. For example, a 100-year ARI event is one that occurs or is exceeded on average once every 100 years.
Average Daily Flowrate The value (which can also be expressed in m3/s) determined from
measured or modelled daily flows (typically expressed in ML/day). It represents the average flow rate over a 24 hour period and is different to peak or instantaneous daily flow.
Bathtub inundation Simplified mapping procedure used to approximate the extent of
inundation caused by increase water level in small open coastal waterbodies. Bathtub modelling delineates inundation extents using water elevation level overlaid on ground elevation. The modelling approach assumes that there is no water level gradient across the waterbody, i.e. the waterbody is essentially a ‘bathtub’ that fills with water. Also referred to as the ‘bucket fill' method.
Digital Elevation Model A digital representation of ground surface topography or terrain. Also
known as a Digital Terrain Model (DTM).
TUFLOW-FV Two and three-dimensional hydrodynamic model developed by BMT
WBM which is suitable for predicting the velocity, temperature and salinity distribution in natural water bodies subjected to external environmental forcing such as wind stress, surface heating or cooling.
Percentage Exceedance The value of a variable above which a certain percent of observations fall.
The 20% exceedance is the value (or score) below which 80 percent of the observations may be found. That is, only 20% of the observations exceed the value.
Bellingen Shire Estuary Inundation Mapping vii Glossary of Terms
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Peak Flowrate The highest discharge (typically expressed in m3/s) found in a river
channel in response to a particular rainfall event. The peak flow corresponds to the point of the hydrograph that has the highest flow.
Practical Salinity Units Ocean salinity is generally defined as the salt concentration in sea water.
It is measured in unit of PSU (Practical Salinity Unit), which is a unit based on the properties of sea water conductivity. It is equivalent to parts per thousand or to g/kg.
Flood Level The height of the flood described either as a depth of water above a
particular location (e.g. 1 metre above a floor, yard or road) or as a depth of water related to a standard level such as Australian Height Datum (e.g. flood level was 7.8 m AHD). Terms also used include flood stage and water level.
Light Detection and Ranging LiDAR is an optical remote sensing technology that measures properties
of scattered light to find range / distance and can be used to measure surface elevations relative to a known datum.
Mean High Water MHW is the average of all high waters observed over a sufficiently long
period of time. Mean High Water Spring MHWS is the average of all high water observations at the time of spring
tide over a sufficiently long period of time.
Mean Higher High Water Solstice Spring MHHWSS (also known as King tides) are higher high waters that occur
around July and December. The average of all higher high waters observed over a sufficiently long period of time.
Mean Sea Level MSL is the average limit of tides and is calculated as the arithmetic mean
of hourly heights of the sea at the tidal station observed over a sufficiently period of time.
Percentile The value of a variable below which a certain percent of observations fall.
The 20 percentile is the value (or score) below which 20 percent of the observations may be found.
Sea Level Rise SLR is the long-term increase to mean sea level.
Source for Catchments An integrated (whole of catchment) model developed by eWater (publicly
owned not-for-profit organisation).
TUFLOW One-dimensional (1D) and two-dimensional (2D) flood and tide simulation
software developed by BMT WBM. It simulates the complex
hydrodynamics of floods and tides using the full 1D St Venant equations
and the full 2D free-surface shallow water equations.
Bellingen Shire Estuary Inundation Mapping viii Contents
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Contents
Executive Summary i
Glossary of Terms vi
1 Introduction 1
2 Background Information 2
2.1 Description of Estuaries in Study Area 2
2.2 Previous Local Studies 2
2.2.1 Flood Studies 2
2.2.2 Estuary Studies 7
2.2.2.1 Estuary Process Study 7
2.2.2.2 Estuary Management Study and Plan 9
2.2.3 Other Relevant Studies 10
2.2.3.1 Coastal Vegetation Mapping 10
2.2.3.2 Health Plans for the Bellinger and Kalang Rivers 11
2.2.3.3 Bellinger Estuary Action Plan Reach Plan 12
2.2.3.4 Bellinger and Kalang Rivers Estuary Action Plan Stage 2 13
2.2.3.5 Bellinger-Kalang Rivers Ecohealth Project 13
2.2.3.6 Bellinger and Kalang River Estuaries Erosion Study 13
2.2.3.7 Bellingen Council Climate Change Risk Assessment 14
2.2.3.8 Bellingen Climate Change Adaptation Strategy 15
2.3 Relevant Research into Estuarine Sea Level Rise Impacts 15
2.3.1.1 Coastal saltmarsh vulnerability to climate change in SE Australia 15
2.3.1.2 Predicting the response of coastal wetlands of south eastern Australia to Sea Level Rise 16
2.3.1.3 Derwent Saltmarsh Response to Sea Level Rise 17
2.3.1.4 Estuary Adaptation to Climate Change 17
2.3.1.5 Anticipated Response Coastal Lagoons to Sea Level Rise 18
3 Estuary Inundation Modelling 20
3.1 Bellinger and Kalang River 20
3.1.1 Description and Review of Existing Flood Model 20
3.1.2 Required Updates to Flood Model 22
3.1.3 Development of Tidal Boundary Conditions 24
3.1.4 Tidal Inundation Model Results and Extents 28
3.1.5 Comparison of Tidal Inundation to Fluvial Flooding 28
3.2 Dalhousie and Oyster Creeks 35
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3.2.1 Background and Key Processes 35
3.2.2 Determination of ICOLL Design Water Levels 35
3.2.3 Determination of ICOLL Design Flood Extents 36
4 Estuary Inundation Risk Assessment 39
4.1 Application of a Risk-Based Framework 39
4.2 Likelihood of Estuary Inundation 41
4.2.1 Likelihood Scale 41
4.2.2 Likelihood of Coastal Inundation 42
4.3 Consequence of Estuary Inundation 44
4.3.1 Consequence Scale 44
4.3.2 Register of Public and Private Assets Potentially Affected 44
4.4 Analysis of the Level of Risk 47
4.5 Estuary Inundation Risks Register 48
4.6 Triggers for Implementation 53
5 Estuary Ecological Modelling 55
5.1 Development of Hydrological Inputs 55
5.1.1 The Source Modelling Framework 55
5.1.2 Model setup 56
5.1.2.1 Overview 56
5.1.2.2 Catchment delineation and model extents 56
5.1.2.3 Functional units 57
5.1.2.4 Rainfall-runoff model 61
5.1.2.5 Meteorological data 61
5.1.2.6 Catchment parameters 63
5.1.3 Estimation of daily Runoff Volume 67
5.1.4 Selection of a Representative Inflow Timeseries 69
5.2 Development of the Estuary Model 72
5.2.1 Scope and Objectives 72
5.2.2 Model Selection 72
5.2.3 Model Geometry and Extent 73
5.2.4 Bathymetry 73
5.2.5 Model Configuration 73
5.2.6 Boundary Conditions 76
5.2.7 Long-term Estuary Modelling Scenarios 76
5.3 Estuary Modelling Results 77
5.3.1 Long-section Profiles 77
5.3.2 Cumulative Frequency Curves 84
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6 Interpretation and Risk Based Assessment of the Eco logical Impacts 87
6.1 Overview 87
6.2 Methodology 87
6.2.1 Study Area 87
6.2.2 Mapping of High Value Natural Assets 87
6.2.3 Biodiversity Consequences of SLR 90
6.2.4 Risk Assessment 90
6.2.5 Monitoring Sites 90
6.2.6 Assumptions and Limitations 90
6.3 Habitats and Landform of the Study Area 91
6.3.1 The Bellinger River - Upper Estuary 91
6.3.2 The Bellinger River - Mid Estuary 91
6.3.3 The Bellinger River - Lower Estuary 92
6.3.4 The Kalang River - Upper Estuary 92
6.3.5 The Kalang River Mid-Estuary 92
6.3.6 The Kalang River - Lower Estuary 92
6.3.7 The Kalang River Marine Tidal Delta and Urunga Lagoon 93
6.4 High Value Natural Assets 93
6.4.1 Seagrass 94
6.4.2 Mangroves 94
6.4.3 Coastal Saltmarsh 94
6.4.4 Swamp Oak Forest 95
6.4.5 Freshwater Wetlands 95
6.4.6 Swamp Sclerophyll Forest 95
6.4.7 Rainforests 96
6.4.8 Subtropical Coastal Floodplain Forest 96
6.4.9 Themeda Grassland on Seacliffs and Coastal Headlands 96
6.4.10 Riparian Corridor 97
6.4.11 Groundwater Dependant Ecosystems 97
6.4.12 State Environmental Planning Policies 98
6.5 Biodiversity Consequences of Sea Level Rise 101
6.5.1 Broad SLR Ecological Impacts 101
6.5.1.1 Seagrass 102
6.5.1.2 Mangroves 102
6.5.1.3 Coastal Saltmarsh 104
6.5.1.4 Swamp Oak Forest 105
6.5.1.5 Floodplain Habitats 105
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6.5.1.6 Riparian Corridor 106
6.5.1.7 Groundwater Dependant Ecosystems 106
6.5.1.8 Beaches 106
6.5.1.9 Threatened Species 107
6.6 Assessment of Risk 107
7 Summary and Discussion 116
7.1 SLR and Changed Frequency of Inundation 116
7.2 Tidal Inundation 116
7.2.1 Bellinger River 117
7.2.2 Kalang River 118
7.2.3 Dalhousie Creek and Oyster Creek 119
7.3 Limitations of Inundation Mapping and Modelling 119
7.4 Suggested Provisions for Reviewing and Updating SLR Benchmarks 120
7.4.1 Independence of Mapping from Changes to Projected Rates of SLR 121
7.5 Sea Level Rise Mitigation Options 122
7.5.1 Estuary Inundation 122
7.5.2 High Value Natural Assets 125
7.5.2.1 Tidal/Near-Tidal Wetlands 125
7.5.2.2 Riparian Corridor 125
7.5.2.3 Floodplain Habitats 126
7.5.2.4 Littoral Rainforest 126
7.6 Proposed Monitoring Sites 127
8 Conclusions 128
8.1 Estuary Inundation 128
8.2 Ecological Impacts 129
9 References 131
Appendix A Description of Wave Setup A-1
Appendix B Mapping Compendium of Estuary Inundation B-1
Appendix C Asset Risk Register C-2
Appendix D Threatened Species Records D-3
List of Figures
Figure 2-1 Bellingen LGA Coastline and Estuaries 3
Figure 3-1 Tuflow Model Setup 23
Figure 3-2 Design Spring Tides 25
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Figure 3-3 Design King Tides 26
Figure 3-4 Design Tides for 20 and 100yr ARI Events 27
Figure 3-5 100-year Design Tides 27
Figure 3-6 Reported Peak Water Level Locations and Long Section Profiles 29
Figure 3-7 Bellinger River Peak Water Level Long Section (Design Spring Tides) 31
Figure 3-8 Bellinger River Peak Water Level Long Section (Design King Tides) 31
Figure 3-9 Bellinger River Peak Water Level Long Section (Design 20-year ARI Tides) 32
Figure 3-10 Bellinger River Peak Water Level Long Section (Design 100-year ARI Tides) 32
Figure 3-11 Kalang River Peak Water Level Long Section (Design Spring Tides) 33
Figure 3-12 Kalang River Peak Water Level Long Section (Design King Tides) 33
Figure 3-13 Kalang River Peak Water Level Long Section (Design 20-year ARI Tides) 34
Figure 3-14 Kalang River Peak Water Level Long Section (Design 100-year ARI Tides) 34
Figure 3-15 Adopted Design ICOLL Water Level Exceedance Curves 37
Figure 4-1 Risk Management Framework (ISO 31000:2009) adapted to Coastal Zone Management 40
Figure 4-2 Summary of Estuary Inundation Risk for the Immediate Timeframe 50
Figure 4-3 Summary of Estuary Inundation Risk for the 2050 Timeframe 51
Figure 4-4 Summary of Estuary Inundation Risk for the 2100 Timeframe 52
Figure 4-5 Continuum Model for Climate Change Adaption Action 53
Figure 5-1 Subcatchment Delineation 58
Figure 5-2 Functional Units Used by the Catchment Model 60
Figure 5-3 Catchment Average Rainfall used by the Catchment Model 62
Figure 5-4 Catchment Average APET used by the Catchment Model 62
Figure 5-5 Daily Rainfall Data (August 2007 – December 2012) 63
Figure 5-6 Daily Streamflow Data (August 2007 – December 2012) 64
Figure 5-7 Calibrated Daily Runoff Volume (modelled vs observed) 65
Figure 5-8 Timeseries of Modelled and Observed Runoff Volume 66
Figure 5-9 Calibrated Flow Duration Curve (2007 – 2012) 66
Figure 5-10 Timeseries of Daily Runoff Volume (1900 – 2012) 68
Figure 5-11 Box and Whisker Plot of Monthly Modelled Flow for the Bellinger River Sub-catchment 69
Figure 5-12 Flow Duration Curve for Bellinger River Sub-catchment (1900-2012) 70
Figure 5-13 Timeseries of Major Inflows to the Estuary (Jan 2005 to Dec 2005) 71
Figure 5-14 TUFLOW-FV Model Mesh and Bathymetry 74
Figure 5-15 TUFLOW-FV Manning's n Distribution 75
Figure 5-16 Long-term Estuary Modelling Reporting Locations and Long Section Profiles 79
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Figure 5-17 Long Section Profiles of Water Level for the Bellinger River 80
Figure 5-18 Long Section Profiles of Salinity for the Bellinger River 81
Figure 5-19 Long Section Profiles of Water Level for the Kalang River 82
Figure 5-20 Long Section Profiles of Salinity for the Kalang River 83
Figure 5-21 Cumulative Frequency Curves (Water Depth) 85
Figure 5-22 Cumulative Frequency Curves (Salinity) 86
Figure 6-1 High Value Natural Assets of the Bellinger and Kalang Rivers, Floodplains and Estuaries 88
Figure 6-2 High Ecological Values GDE’s Bellinger-Nambucca Coastal Sands 99
Figure 6-3 High Ecological Values GDE’s Coastal Bellinger Alluvial 100
Figure 6-4 High Ecological Values GDE’s Coastal Kalang Alluvial 100
Figure 6-5 Predicted High Value Natural Asset SLR Impacts 103
List of Tables
Table 2-1 Peak Ocean Levels (from WMA, 2012) 6
Table 2-2 Design Flood Levels at Key Locations (from WMA, 2012) 6
Table 2-3 Modelled Climate Change Results (1% AEP) (from WMA, 2012) 7
Table 3-1 Peak Offshore Ocean Levels Adopted for Bellinger-Kalang River Estuary 24
Table 3-2 Peak Offshore Tide Levels for Five SLR Scenarios 26
Table 3-3 Summary of Peak Tidal Water Levels (m AHD) for Bellinger and Kalang Rivers 30
Table 3-4 Peak Ocean Levels for Dalhousie and Oyster Creeks 37
Table 3-5 ICOLL Peak Inundation Level for five SLR Scenarios 38
Table 4-1 Risk Likelihood / Probability for Coastal Hazards 42
Table 4-2 Timeframes for Coastal Planning 42
Table 4-3 Estuary Inundation Likelihood Summary 43
Table 4-4 Consequence Scale for Estuary Inundation 45
Table 4-5 Updated Ecological Community Consequence Ratings 46
Table 4-6 Consequences Ascribed to Assets in the Study Area 46
Table 4-7 Risk Matrix for Estuary Inundation 48
Table 5-1 Major Sub-catchment Details 56
Table 5-2 Sub-catchment Properties 59
Table 5-3 Summary of Meteorological Data 61
Table 5-4 SIMHYD Rainfall-Runoff Parameters for Bellinger River Sub-catchment 64
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Table 5-5 Additional SIMHYD Rainfall-Runoff Parameters for Lower Estuary Sub-catchments 67
Table 5-6 Long-term Estuary Salinity Modelling Scenarios 76
Table 5-7 Summary of Modelled Salinity Profiles (Median Salinity) 77
Table 5-8 Summary of Cumulative Frequency Results 84
Table 6-1 High value natural asset types and data sources 89
Table 6-2 Sea Level Rise Risk Assessment and Mitigation Options for High Value Natural Assets 109
Table 7-1 Adopted Ocean Levels for Bellinger-Kalang Estuary and Coastline 116
Table 7-2 Peak Tide Level at Major Bridge Crossings 117
Table 7-3 Recommended Options for Managing Estuary Inundation Hazard 122
Table 7-4 Habitat Response to SLR Monitoring Sites 127
Bellingen Shire Estuary Inundation Mapping 1 Introduction
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1 Introduction
Climate change and sea level rise (SLR) have the potential to impact private and public land and
assets within the Bellingen Shire Local Government Area (LGA) as well as other coastal areas
around NSW and Australia. BMT WBM was commissioned by Bellingen Shire Council (BSC) to
systematically and comprehensively identify the extent of SLR risks facing the BSC LGA, by
determining the estuarine inundation depths and extents and the physical and ecological assets at
risk.
The study investigated a range of SLR scenarios including mean sea levels (MSL) of 0.0, 0.4, 0.7,
0.9 and 1.4 m AHD. These levels are based on the previous NSW Government planning
benchmarks which are a projected rise in sea level (relative to the 1990 mean sea level) of 0.4
metres by 2050 and 0.9 metres by 2100 (DECCW, 2009). It is important to note that due to the
inherent difficulty in forecasting actual rates of sea level rise (SLR) the mapping in this study shows
the impact of 0.0, 0.4, 0.9 and 1.4 metres of SLR but does not specify the timing of these changes
to mean sea level.
For each SLR scenario, four design events were considered, including:
• Mean High Water Spring;
• Highest High Water Spring Solstices (i.e. approx. King Tide);
• 20-year Average Recurrence Interval (5% AEP); and
• 100-year Average Recurrence Interval (1% AEP).
Inundation extents for the Bellinger and Kalang Rivers were determined using an existing flood
model (TUFLOW) for each combination of design event and SLR scenario. An assessment of tidal
inundation risk for Dalhousie and Oyster Creek lagoons was undertaken using a bath-tub approach
and design conditions appropriately derived for their location based on available water level
records for other similar waterbodies. The modelled design flood levels and inundation extents
were used to map areas of current and future tidal inundation and also to assess the risk to
infrastructure (built environment) assets.
To determine the influence of SLR on ecological assets within the BSC, a 12 month simulation of
estuary conditions (water levels and salinity) was undertaking using a flexible mesh (TUFLOW-FV)
estuary model. The 12 month simulation used appropriate hydrological inputs (calculated using a
catchment model (developed as part of the study) and investigated MSL conditions of 0.0, 0.4, 0.9
and 1.4 m AHD. Changes to the duration and frequency of inundation and also to the salinity
regime were then used to infer potential ecological change along the estuarine regions of BSC.
The study also involved a site visit to undertake ‘ground-truthing’ of infrastructure and ecological
assets and risks, and also provides suggested potential mitigation options to reduce the level of
future risk due to SLR.
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2 Background Information
2.1 Description of Estuaries in Study Area The Bellingen Shire Local Government Area (LGA) is located on the NSW Mid North Coast and
includes some 15 km of coastline extending from Oyster Creek in the south to Tuckers Rocks in
the north.
Three notable coastal entrances are situated along the Bellingen coastline, namely Oyster Creek
and Dalhousie Creek (which are small creeks intermittently open to the ocean) and the larger
Bellinger / Kalang River with its partially trained entrance at Urunga (see Figure 2-1).
The floodplains of the Kalang and Bellinger Rivers between Urunga and Mylestom are low-lying
and subject to potential inundation impacts of Climate Change and SLR. The impact to both private
and public land as well as assets within the BSC LGA (if realised) is significant.
2.2 Previous Local Studies A review of past local studies has been undertaken to ensure that recent relevant information is
included in the current SLR study. A brief summary of local studies and their relevance to the
current SLR study is provided in the following sections.
2.2.1 Flood Studies
The most recent, comprehensive and up-to-date flood study for the Bellinger and Kalang Rivers is
WMA (2012). This report was produced by WMA Water for the Roads and Maritime Services
(RMS). The objective of the study was to define the existing flood behaviour within the Lower
Bellinger and Kalang Rivers to assist with:
• The design of major river crossings for the Warrell Creek to Urunga Pacific Highway upgrade
project; and
• To be extended into a flood study under the NSW Flood Policy.
The study area was defined to include those areas between the river entrance at Urunga
(downstream) to upstream extents on the Bellinger River at Bellingen Bridge (Lavenders Bridge)
and approximately 2.5 km past the Brierfield Bridge on the Kalang River.
The flood study report details the investigations, results and findings of the hydraulic modelling
study undertaken for the Bellinger and Kalang Rivers. The key elements of that report include:
• a summary of available data;
• hydraulic model development;
• calibration of the hydraulic model; and
• definition of the design flood behaviour through the analysis and interpretation of model results.
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Figure 2-1 Bellingen LGA Coastline and Estuaries
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The WMA (2012) report provides a brief overview of a number of previous flood related studies,
which have generally been superseded by the most recent hydraulic study including:
• New South Wales Coastal Rivers Floodplain Management Studies Bellinger Valley (Cameron
McNamara, December 1980);
• Proposed Industrial Area, Urunga NSW (Outline Planning Consultants, May 1984);
• Bellinger River May 1980 Flood Report (PWD, 1981);
• Bellinger River Flood History 1843-1979 (PWD, 1980);
• Lower Bellinger River Flood Study (PWD, 1991);
• Lower Bellinger River Flood Study, Location of Flood Marks Engineering Survey Brief (Cameron
McNamara, 1991);
• Lower Bellinger River Flood Study Compendium of Data (PWD, 1991);
• Bellinger and Kalang River’s Floods of February and March 2001 (Bruce Fidge and Associates,
2003);
• Floodplain Risk Management Study Stage 2 – An Assessment of Floodplain Management
Options and Strategies (Bellingen Shire Council, April 2002);
• Upper Kalang River Flood Assessment, (Bellingen Shire Council, December 2006);
• South Arm Road Flood Study (Final) (DeGroot and Benson Pty Ltd, June 2000);
• Upper Bellinger River Flood Assessment (Bellingen Shire Council, 2006);
• Newry Island Flood Study Draft (WMAwater, 2008);
• Warrell Creek to Urunga Upgrade Environmental Assessment (RTA, 2010);
• Review of Bellinger, Kalang and Nambucca Rivers Catchment Hydrology (WMAwater, 2011);
• Kalang River – 2009 Flood Event (WMAwater, 2011); and
• Bellinger and Kalang Rivers Flood Event of 31 March 2009 Collection and Collation of Flood
Data (Enginuity Design, 2010).
The Bellinger and Kalang River valleys have a long history of flooding. Flood records for Bellingen
date back to the 1840’s and there have been 26 floods on the Bellinger River the greatest of which
has produced flood peaks of above 8.0 m AHD at the Bellingen Bridge. More recent flood events
for which significant data are available for calibration and validation purposes occurred in 1974,
1977, 2001 and 2009.
The report indicates that there is sufficient data available for calibration and validation purposes
including water level gauges at Newry Island, Urunga, Repton and Bellinger Bridge as well as a
range of surveyed peak flood levels throughout the study region.
Modelling Approach
A hydrologic (WBNM) model was established for each catchment to determine inflows into the
hydrodynamic flood model. A combined one and two dimensional hydrodynamic (TUFLOW) model
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was used to define the flood behaviour using ALS, hydrosurvey and other flood control details (e.g.
culverts and levees).
The TUFLOW models were calibrated and verified to a range of historical events including 1974,
1977, 2001 and 2009. The calibrated hydraulic models were then used to assess the flood levels
and hydraulic flood hazard for the 5-year ARI and the 10%, 2%, 1%, 0.5%, 0.2%, 0.05% Annual
Exceedance Probability (AEP) and Probable Maximum Flood (PMF) design events.
The TUFLOW flood model consisted of a 15 metre by 15 metre grid defining the channel and
overbank floodplain area for the Bellinger River, lower Kalang River and its tributaries. The upper
reaches of the Kalang River were defined by a combined one and two dimensional model, with the
one dimensional network defining the main channel and the two dimensional model domain
defining the floodplain. The flood model which has been utilised for this study is described in more
detail in Section 3.1.
Model Calibration and Validation
The 1974 and 1977 events were used for calibration of the hydraulic model. The modelled flood
levels for the 1974 event were generally within 0.4 metres of the observed values, with a tendency
to over-predict flood levels in the upper reaches and under predict them in the lower portion of the
river. The modelled flood levels for the 1977 event were generally within 0.1 metres of the
observed levels except for the lower reaches where the adopted downstream boundary is
uncertain.
The 2001 and March/April 2009 events were used for model validation. For the 2001 event, the
model calibrated well with modelled levels generally within 0.2 metres of the observed flood levels.
For the March/April 2009 event, a poor calibration was achieved in the Upper Kalang River,
however, for the remainder of the model area a good model calibration was achieved. On the
Bellinger River, the magnitude of the event is between a 10% and 2% AEP event, while on the
Kalang River the event was even larger (between 2% and 0.5% AEP).
Adopted Design Boundary Conditions
Inflows and boundary conditions for the TUFLOW model consist of a number of time-varying flow
hydrographs developed using the WBNM catchment model and Bureau of Meteorology (BoM)
design Intensity-Frequency-Duration (IFD) rainfall data. At the downstream boundary of the flood
model, a tailwater level defining the river entrance was used. The tailwater conditions (as
presented Table 2-1) were based on recorded tide levels at Coffs Harbour, experience on nearby
catchments and OEH guidelines.
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Table 2-1 Peak Ocean Levels (from WMA, 2012)
Design Event Peak Level (m AHD)
5-year ARI 1.45
10% AEP 1.64
2% AEP 2.0
1% AEP 2.1
Modelled Design Event Results
Maps of peak flood levels and velocities for the 5-year ARI, 10, 2, 1, 0.5, 0.2 and 0.05 % AEP and
Probable Maximum Flood (PMF) design events were presented in the report and tabulated as
reproduced below in Table 2-2.
Table 2-2 Design Flood Levels at Key Locations (fro m WMA, 2012)
Modelled Climate Change Results
The study also investigated the impacts of climate change including:
• increases in peak rainfall and storm volume of 10%, 20% and 30%; and
• an increase to MSL (sea level rise) of 0.4 metres and 0.9 metres.
Table 2-3 presents the results of the impacts of climate change for the 1% AEP event. The climate
change results show that away from the immediate mouth area (i.e. near the river confluence) the
impacts of increases in MSL due to SLR are less than 11 cm and in most places less than 4 cm.
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Table 2-3 Modelled Climate Change Results (1% AEP) (from WMA, 2012)
2.2.2 Estuary Studies
2.2.2.1 Estuary Process Study
An Estuary Process Study of the Bellinger and Kalang River System was prepared in 2003 on
behalf of the Bellingen Shire Council and the Department of Infrastructure, Planning and Natural
Resources by Lawson & Treloar (2003).
The model study included the development of both a hydrologic (MUSIC) and hydraulic (DELFT3D)
model. A review of the DELFT3D model shows that it was of the estuary channel only and hence
was not suitable for the current SLR study.
The catchment model was calibrated for the period 1 January 1996 to 31 December 1996
achieving less than 10% difference between annual recorded and modelled flow volumes at Thora.
However, validation of the model for the period 1 January 1995 to 31 December 1995 achieved a
greater difference (30%) between annual recorded and modelled flow volumes at that same
location.
The main findings of that investigation are summarised under the following headings.
Estuary Type and Features
• The estuary is classified as being a wave dominated delta. The estuary has evolved over
geological time with the primary forcing factors being sea level change, riverine flows, episodic
flooding and wave climate;
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• Since European settlement, the estuary has further changed with primary forcing factors being
human intervention with the partial training of the entrance and the river channels and the
forestry industry occurring in the upper catchment;
• The geomorphology of the system is one of wide low gradient rivers on coastal plains with
irregular meanders. The river channel is up to 60 metres wide at some locations, but with a low
channel slope in the estuarine reaches; and
• The salinity of the rivers varies with the limit of saline penetration being about 24 km upstream
of the entrance on the Bellinger River and 20 km upstream of the entrance in the Kalang River.
The salinity structure is generally well mixed, but a salt wedge can form periodically following a
period of fresh water flow.
Catchment and Floodplain Processes
The study catchment is largely forested or national park with small pockets of urban development
located within. In the lower estuary, the floodplain is largely used for agricultural purposes with
some industry (e.g. dairy farming and a former antimony processing site).
Hydrodynamics
Hydraulic processes within the Bellinger and Kalang Rivers are dominated by flood and ebb tidal
movements as well as freshwater inflows from the upper catchments. The hydrodynamics of the
system are also controlled by the partially trained entrance and the half-tide training walls
constructed in the early 1900’s, which restrict tidal flow to some areas (most notably Urunga
Lagoon).
Water Quality Processes
Water quality processes within the rivers are also dominated by tidal inflows and outflows, as well
as inputs within the catchment from both diffuse and point sources. The lower portions of the rivers
are well flushed by the astronomical tides (the lower reaches of around 8 km length), whilst the
upper reaches of the estuary rely on freshwater inflows for periodic flushing and to maintain good
water quality.
The water quality of Urunga Lagoon has the longest and most consistent data record. Available
data indicate that the ambient quality of the water in Urunga Lagoon is generally within ANZECC
(2000) guidelines. Nonetheless, the community reports an alternate view of water quality of the
Lagoon. Data indicate that the water quality in wet weather conditions appears to be an issue, but
certainly within the range of values expected for an estuarine system with urban runoff contribution
(Lawson & Treloar, 2003).
Sedimentary Processes
Sedimentary processes within the estuary are dominated by marine sand intrusion in the lower
portions of both the Bellinger and Kalang Rivers from the open coastal zone, whilst the upper
reaches of the estuary are dominated by fluvial sediment inputs. Marine intrusion is controlled by
the entrance training walls, which form an interruption to the littoral sand drift along the coast.
Episodic catchment flood events of small magnitude result in the transport of fluvial material down
the estuary. Larger magnitude events can result in significant bank and bed scour in the estuarine
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and freshwater reaches of the river, causing deposition of fluvial materials within the estuary,
scouring of the entrance bar and deposition of sediments offshore. Limited sampling of sediment
quality undertaken during estuary processes study indicates that sediment quality is reasonable
and within the ANZECC (2000) guidelines for the estuary. Acid sulfate soils are a considerable
potential issue for the estuary, however, no data are available to indicate actual acid sulfate soil
issues and associated low pH of estuarine water, fish kills associated with low pH or metal releases
from sediments.
Flora and Fauna
The ecology of the estuary consists of a variety of flora and fauna with some threatened and
endangered species (see Appendix D for more detail). The estuary also contains a number of
SEPP14 wetlands and the catchment contains a small pocket of SEPP26 littoral rainforest. Field
mapping of seagrass and mangroves was undertaken as part of study as well.
Human Impacts
Recreational usage varies along the length of the estuary, with a variety of water-based activities,
including water skiing, fishing, sailing kayaking and swimming. The stability of riverbanks is an
ongoing issue, noticeable for over 40 years and is largely a result of human impact in the upper
reaches of the river and catchment as well as modifications to the riparian vegetation in the
estuarine areas (e.g. clearing for agriculture and cattle grazing).
Concluding Remarks
Overall, the estuary is a modified system, but appears to be functioning well, given the wide range
of uses and the human impacts throughout the catchment. The interactions amongst the processes
are complex and the ongoing recognition of these interactions through the management phase of
the estuary management process will be vital to ensure that the value of the estuary is maintained
and enhanced.
2.2.2.2 Estuary Management Study and Plan
The Estuary Management Study for the Bellinger and Kalang Rivers was completed by BMT WBM
in 2007 on behalf for the BSC. The study consisted of a broad range of components including a
detailed review of the estuary's environmental attributes, societal uses/values and existing
management frameworks (statutory and non-statutory). Arising from this review and consideration
of community and stakeholder input, issues for future management were identified. Management
objectives were developed to address these issues and with the assistance from the local
community were prioritised. The outcomes of that report form the basis for the future estuary
management plan (BMT WBM, 2007a).
The Estuary Management Plan (EMP) for the Bellinger and Kalang Rivers was completed by
BMT WBM in 2007 and adopted by BSC in May 2008. The report presents prioritised management
strategies and actions for the Bellinger and Kalang River estuary to be implemented over the next
five or more years. The main issues affecting the long-term management of the Bellinger and
Kalang River estuaries were compiled from a number of different sources and have been collated
into the table reproduced below.
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Twenty four (24) management objectives were defined and prioritised. The estuary management
plan contains details of each of the objectives, suggested tasks and resources to meet the
objectives (including responsible agencies, approximate timeframes, costs and potential funding
sources). Management Objective 20 (Ensure climate change and sea level rise implications are
incorporated into Council’s planning horizon) will be partly fulfilled by completion of this SLR study.
2.2.3 Other Relevant Studies
2.2.3.1 Coastal Vegetation Mapping
The Bellingen Coastal Vegetation Mapping Project was undertaken by Flametree Ecological
Consulting on behalf of BSC in 2006. The relevant outcomes of the study include:
• Identification and mapping of vegetation communities on public land in the coastal parts of the
Bellingen LGA (the Study Area);
• Identification and mapping of Endangered Ecological Communities in the Study Area;
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• Mapping of the incidence and severity of infestations of weed species at selected points in the
Study Area; and
• Mapping of vegetation condition (weed levels) over the whole of the study area.
The study area (i.e. the area mapped) consists of public land in the coastal parts of Bellingen LGA
from Tuckers Rocks to Wenonah Head. The mapping was typically restricted to between 50 and
200 metres from the coast and did not include any areas along the Bellinger / Kalang estuary
outside of the coastal fringe.
GIS output from the study have been used in the ecological risk assessment of the SLR study.
2.2.3.2 Health Plans for the Bellinger and Kalang Rivers
The Bellinger River Health Plan (BSC, 2010a) and the Kalang River Health Plan (BSC, 2010b) are
both community-driven, action-oriented plans which have been prepared in a partnership between
the NSW Department of Environment and Climate Change (DECC) and BSC.
The purpose of these two plans is to document the issues which affect river health from community
and agency perspectives and priorities, and to assess how these issues currently impact on water
quality and river health. The plans recommend actions to address issues and improve
management though best practice.
These documents are of interest to the current study in that they both identify a range of issues
(which includes sea level rise) impacting on the study area. The impacts of SLR identified by the
plans are reproduced below.
Impacts of Sea Level Rise
The impacts of rising sea level are many. There is the predicted salt water intrusion into aquifers
and estuaries, affecting coastal ecosystems, water resources and human settlements. There will be
changes in the distribution and extent of coastal wetlands, impacting upon agriculture and low lying
urban settlements. There will be changed flushing behaviour of estuaries. Coastal impacts are
likely to be shoreline recession and realignment of beaches.
The intrusion of salt water into the aquifer is of particular concern to Council because the extractive
bores that supply the towns of Bellingen and Urunga lie approximately 1 km upstream of the
current known tidal limit. In addition to this, further salt water intrusion into the estuary might affect
the utility of certain sections of the Bellinger River and Kalang River for irrigation purposes.
Whilst the global impacts of climate change are becoming increasingly clear, it is still uncertain
what the effects on local systems like the Bellinger and Kalang Rivers will be. The science required
is complicated. Coastal erosion effects will almost certainly result in increased sediment deposition
within estuaries. The impacts of this upon estuarine ecosystems will be dependent upon specific
rates of sedimentation, rates of sea level rise and elevation-dependent accommodation space for
migration of mangroves, salt marshes and seagrasses.
Sea level rise will impact on drainage and groundwater in the Bellinger-Kalang coastal floodplain.
The specific effects may be increased flood levels and duration, water logging of soils, soil
salinisation and reduced irrigation amenity of groundwater due to saline intrusion (CSIRO, 2007).
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Sea level rise will also result in an upstream migration of the saltwater/freshwater interface (Newton
2008). This could be exacerbated by reductions in average freshwater flows associated with
climate change predictions. Increased acidification of estuarine waters could also result. Greater
fluctuations in the levels of groundwater could potentially increase the risk of exposure of acid
sulfate soils which, when combined with a higher proportion of rainfall falling in storm events, could
escalate the potential for delivery of acid water. In addition, higher concentrations of carbon dioxide
in the atmosphere are lowering the pH of oceanic waters. The impacts of this on shell-forming
creatures and the ecosystems they support are potentially enormous.
Planning for sea level rise is complicated by other factors. The increase in sea level will exacerbate
the effects of extreme sea level events known as storm surges. Storm surges are regular events
where storm associated low air pressure and high winds create a temporary surge in local sea
levels. Against a background of elevated sea levels, storm surges are predicted to more frequently
inundate low lying urban and agricultural areas and to more fully impact upon coastal geography as
seawater penetrates further inland and causes greater erosion.
The worldwide increase in the number of people flooded per year with a sea level rise of 1 metre is
expected to increase more than tenfold (CSIRO, 2008). Increases in severe storm events and an
extension of the tropical cyclone zone further south will result in high winds and extreme wave
events that will further erode coastlines and add to the encroachment of seawater into catchments
and urban areas. In general we are likely to see increased coastal inundation, erosion, significant
changes to estuarine ecosystems, water quality and hydrodynamics and groundwater resources.
2.2.3.3 Bellinger Estuary Action Plan Reach Plan
The Bellinger Estuary Action Plan Reach Plan (BSC, 2011) identifies key threats to the Upper-Mid
Bellinger River Estuary (Bellingen to McGeary’s Island) and makes recommendations in regards to
actions to address those threats. Recommendations are made at the reach scale and then used to
develop a Site Action Plan (SAP) for each property.
In the upper-mid estuary, episodic fluvial processes (driven by freshes and floods) tend to create
issues such as bank scour, slumping failures. Other degrading processes resulting from wave
action (wind and boat), unmanaged stock access, inappropriate land use or the
removal/suppression of riparian vegetation place ongoing pressure on the system at specific
locations.
A riparian baseline assessment of the study reach was undertaken by BSC and NRCMA staff
during late August 2010. These data were used to determine the level of intervention required and
the prospective target condition rating for the reach. Parameters collected include:
• Canopy, mid story and ground cover;
• proportion of weed infestation within the canopy, mid story and groundcover zones;
• Weed species densities;
• Data collected may also be used to determine the level of success towards the target condition
rating following intervention Areas of significant erosion;
• Stock access;
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• Riparian regrowth; and
• Riparian width and suitability.
The assessment found that river bank condition in the upper-mid Bellinger River estuary is
generally moderate to poor. Geomorphic and fluvial drivers underpin the general character and
behaviour of the estuary, while more recent anthropogenic influences have resulted in accelerated
changes to the river system and surrounding environments. Landuse practices including historical
gravel extraction, riparian clearing and introduction of exotic species have resulted in a degraded
estuarine ecosystem with limited riparian stability and connectivity. Dense riparian forest that would
have covered the floodplain areas has now been all but removed.
The baseline assessment and associated bank condition data may be used to determine the level
of success towards the target condition rating following intervention, and also provide a historical
baseline of river bank condition that could be used for monitoring future SLR impacts. Land
managers are encouraged to use this Plan to guide activities being undertaken as part of routine
management, which may also be extended to include future management actions to reduce the risk
of SLR to key localities within the estuary.
2.2.3.4 Bellinger and Kalang Rivers Estuary Action Plan Stage 2
The Stage 2 Estuary Action Plan incorporates property scale rehabilitation plans on an estuary
wide scale. It builds on management objectives outlined in the existing EMP to develop estuary
wide priorities to address river health issues, control bank erosion and raise community awareness
of estuarine processes and its sensitivities. A key focus is to supplement the current EMP to
incorporate the impacts of climate change. The planning process engages and empowers
landholders to take action through establishing a set of priorities for protecting and enhancing their
riparian frontage. Additionally, the plan allows Council to prioritise future management interventions
and serves as a platform to obtain additional funding for restoration works.
2.2.3.5 Bellinger-Kalang Rivers Ecohealth Project
Bellinger-Kalang Rivers Ecohealth Project provided an assessment of river and estuarine condition
for 10 freshwater and 12 estuarine locations along the river system for a 12 month period from
October 2009 to September 2010 (Ryder, et. al., 2011). Monthly sampling at each site collected
water chemistry data including pH, conductivity and salinity, dissolved oxygen (DO), temperature,
turbidity, TN, TP, SRP and NOx. An assessment of riparian condition and macroinvertebrate
sampling was also undertaken at the 10 freshwater sites but not for the estuary sites.
The field data collected at the estuary sites may be of future use for calibration of an estuary model
and as baseline datasets to assist with future monitoring of potential ecological impacts caused by
SLR.
2.2.3.6 Bellinger and Kalang River Estuaries Erosion Study
The Telfer and Cohen (2010) erosion study was commissioned by BSC to implement a number of
objectives regarding bank erosion identified in the estuary management plan (refer Section
2.2.2.2).
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The report provides information on the current processes and distribution of erosion in the two
estuaries by:
• Documenting the historical changes that have occurred in the Bellinger and Kalang estuaries
including late Quaternary estuary evolution and changes to land use and hydrological regime
over the past century;
• Identifying and describing geomorphic process zones within each estuary with a particular view
to identifying the occurrence and extent of the main depositional environments (i.e. marine-tidal,
fluvial transition and fluvial dominated), using existing information (documents, reports and
datasets made available by Bellingen Shire Council, New South Wales Department of
Environment, Climate, Change and Water), aerial photography and bathymetric data; and
• Examining the rates and magnitudes of accelerated bank erosion in key areas by analysing
historic and recent hydrographic data and photogrammetric analyses of bank erosion/channel
migration in key areas over the period 1942 to current (2014).
The report also summarises the results of the 2009 field assessment of bank condition including:
• An analysis of the current distribution of bank erosion within the Bellinger/Kalang estuaries
including the identification of areas of current accelerated change with reference to the 2009
floods;
• A description of riparian vegetation condition throughout the estuary area and an explanation of
the correlation between riparian vegetation condition and bank erosion severity; and
• A summary of the distribution and effectiveness of bank protection works and options for future
works that represent current best-practice.
The report also provides management recommendation for future management of erosion within
the two estuaries based on the findings of the study. The analysis of erosion in the Bellinger River
estuary identified twelve sites of erosion significance of which two are considered to be highest
priority for remedial action, while the analysis of erosion in the Kalang River estuary identified
sixteen sites of erosion significance, three of which are considered to require immediate attention.
2.2.3.7 Bellingen Council Climate Change Risk Assessment
The Climate Risk (2010a) report was prepared for BSC to provide information to support local
government climate change risk assessment and adaptation planning and identify a path towards
Council’s resilience to climate change as part of the Australian Government Local Adaptation
Pathway Program (LAPP).
An internal workshop undertaken as part of the study identified twenty five sites of which six were
classed as ‘very high priority’ for 2030. These were damage to roads and infrastructure from storms
and flooding; increased bushfire risks to life and property; increased price of energy from a carbon
constrained economy; threats to the sewer and water system from sea level rise; and isolation of
the community during flooding events.
Relevant chapters from the report regarding sea level rise and the impact on coastal environments
are reproduced below.
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Sea Level Rise and Storm Surge
Sea level rise will not only result in direct erosion problems, but will also further the penetration of
saline water and waves inland. The short-term excursion of saline water into freshwater
environments can result in fish kills and other adverse effects on local fauna and flora populations.
With more frequent storm surge, increased coastal erosion, changing sedimentation patterns, and
disruption of estuarine environments are expected. In addition, high wave events are likely to
significantly alter the sediment patterns of estuarine areas. Beaches and estuarine areas within the
region may be washed away, or have high level of debris and pollutants washed onto them
reducing their aesthetic, natural and recreational value. Impacts on both the natural and built
environment could be significant.
Impacts on Coastal Environments
The coastal habitats within the region, including coastal wetlands, are of significant environmental
value. They provide a diversity of habitat for many aquatic and terrestrial organisms. Importantly,
the region has a number of coastal lakes and lagoons which:
“...typically have intermittently open entrances to the ocean. The lakes are unique in their
biodiversity and their ecological and physical processes. They can alternate between freshwater
and saltwater regimes. These lakes are highly susceptible to impact from climate change and
urban activities.”
Of concern for the preservation of these Intermittently Closed and Open Lake or Lagoons
(ICOLLs), changing sedimentation is highly likely to change this regime. In addition, changing sea
level is likely to inundate these bodies with salt water, increasing salinity concentration and altering
the changing freshwater and saltwater regimes. Bellingen has important estuarine environments
which may alter due to changing sediment loads.
2.2.3.8 Bellingen Climate Change Adaptation Strategy
The Climate Risk (2010b) report was prepared for BSC to provide information on climate change
adaption planning as part of the Australian Government Local Adaptation Pathway Program
(LAPP). The objective of the Adaption Plan is to provide a comprehensive strategy to develop
climate change resilience and adaptive capacity for the mid north coast councils of Nambucca,
Bellingen and Kempsey.
An action raised in the adaptation strategy is data collections (LiDAR acquisition) and undertaking
modelling to quantify the impact of SLR on infrastructure and ecological assets.
2.3 Relevant Research into Estuarine Sea Level Rise Impacts A review of relevant research into the impact of sea level rise on estuarine environments was
undertaken to guide and inform the current SLR study, which is summarised below in the following
sections.
2.3.1.1 Coastal saltmarsh vulnerability to climate change in SE Australia
The Rogers and Saintilan (2009a) paper provides information on the ecological significance of
coastal saltmarsh. Key points outlined by their study include:
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• Coastal saltmarsh has been listed as an Endangered Ecological Community in New South
Wales;
• Recent research has highlighted the importance of coastal saltmarsh as a source of nutrition for
fish, a nocturnal feeding habitat for microbats, and a roosting habitat for several species of
migratory shorebirds;
• Since European colonisation, coastal saltmarsh has been reclaimed for agricultural, residential
and industrial use, and the past five decades has seen a consistent replacement of saltmarsh
by mangrove throughout SE Australia;
• A major problem in coastal wetland conservation is the lack of knowledge on ecosystem
response to sea level and the absence of planning tools for estuarine managers to incorporate
anticipated responses in planning for ecosystem protection in the future; and
• To preserve or enhance ecologically desirable habitat, planning agencies must make
appropriate zoning decisions now in anticipation of climate trends.
2.3.1.2 Predicting the response of coastal wetlands of south eastern Australia to Sea Level Rise
The Rogers & Saintilan (2009b) paper provides information on the predicted response of coastal
wetlands in NSW to SLR.
A summary of key points includes:
• Sea-level rise has been listed as a key threatening process. Over the previous five decades
moderate rates of sea-level rise have coincided with the invasion of saltmarsh by mangrove;
• It has been predicted that the capacity of a wetland to keep pace with sea-level depended on its
ability to maintain elevation though processes of vertical accretion; and
• The original assumption that march development (vertical accretion) keeps pace with sea level
rise was originally postulated in the 1850’s and has only recently been challenged.
The paper provides detail of a study as summarised below:
• Surface elevation tables (SETs) were installed in 12 coastal wetlands in Southeastern Australia
to establish elevation and accretion trajectories for comparisons with mangrove encroachment
of saltmarsh and sea-level rise;
• SETs confirmed that the elevational response of wetlands is more complex than accretion alone
and elevation changes may also be attributed to below-ground processes that alter the soil
volume such as subsidence/compaction, groundwater volume fluctuations, and below-ground
biomass changes; and
• A simple modelling approach was employed to establish a relationship between the observed
rate of mangrove encroachment of saltmarsh and relative sea-level rise, which incorporates the
eustatic component of sea-level rise and changes in the marsh elevation.
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2.3.1.3 Derwent Saltmarsh Response to Sea Level Rise
The Prahalad et. al. (2009) report describes a project whose primary objective was to predict the
future extent and migration pathways of tidal wetlands in the Derwent Estuary in the event of
predicted future sea level rise. The project involved three stages including mapping of the current
extent of tidally influenced wetlands and marshes and analysis, inundation modelling due to SLR
and predicting the future extent of saltmarsh. The project was a preliminary assessment of the
future extent of saltmarshes and freshwater wetlands, and did not include any consideration of the
rates of sedimentation (vertical accretion), wind-wave climate (fetch modelling) and historical
shoreline change.
A number of relevant points extracted from the study include:
• Tidal influence is a primary driver of the development, extent and function of tidal wetlands,
especially saltmarsh;
• They are generally known to occur between the area below the mean high tide mark and the
storm tide mark, with salt spray extending this range further inland in some cases. This
hypothesis was supported by the current landward extent of the saltmarshes within the Derwent
Estuary, which, in most cases, aligned well with the greatest landward intrusion of the modelled
storm tide (i.e. the 1 in 100 year storm tide with current sea level); and
• The future landward extent of the saltmarsh can be reasonably expected to fit with the landward
intrusion boundary of the future modelled storm tide plus the projected sea level rise. A future
tidal wetland extent for the study site was determined based on the above hypothesis, and a
scenario of 110 cm sea level rise in the year 2100. It is possible that saltmarsh may not be able
to establish where ‘concrete human footprints’ exists in the form of houses, roads and other
constructed environments, and hence, the future tidal wetland extent layer should not include
those areas.
2.3.1.4 Estuary Adaptation to Climate Change
The Rogers & Woodroffe (2012) paper describes a range of predicted estuarine response to
climate change based on the geomorphic features of the estuary.
A number of relevant points from the paper include:
• An estuary is a zone where marine water and freshwater derived from catchments merge.
These waters transport sediment from the marine and terrestrial environments where they are
deposited or redistributed to other environments and these sediments provide substrate and
nutrients for the development of biota and ecosystems that are unique to estuarine
environments;
• The relationship between rates of sediment supply and rates of sea-level rise is central to
understanding the geomorphic response of estuaries to climate change. Surplus or deficits of
sediment from a shoreline or estuary over a period are regarded as the ‘sediment budget’. A
positive sediment budget occurs when sediment gained on a coastline exceeds the sediment
lost over a period, with the net result being shoreline progradation or shoreline elevation
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increase; conversely, regression at the geological scale, or erosion at the event scale, is
associated with a negative sediment budget.
• Depositional environments in estuaries are artefacts of positive sediment budgets occurring
under stable sea-level conditions over the mid to late Holocene (and in some cases during the
Pleistocene). Efficient trapping of sediment and evolution towards ‘maturity’ is largely driven by
rates of sediment supply from the catchment and marine environments and the hydrodynamics
within an estuary. Hence mature estuaries exhibit a strongly positive sediment budget, with
rates of sediment supply tending towards equilibrium with sea-level rise, while immature
estuaries exhibit weakly positive sediment budgets, with sediment supply lagging behind rates
of sea-level rise. Analysis of contemporary sediment budgets provides valuable information for
quantifying the response of estuaries to projected sea-level rise in the 21st century.
• Sea-level rise acts to reverse estuary evolution and increases the areal extent of open water
and intertidal areas within estuaries, thereby creating accommodation space for the deposition
of marine sands and terrestrial colluvial deposits, muds and silts. Due to strong hydrological
links between the ocean and estuaries (and even intermittently open estuaries or ICOLLs), base
and maximum water levels within estuaries are projected to increase at rates equivalent to sea-
level rise. The geomorphic response of estuaries to sea-level rise, evident through increased
accommodation space, will vary in accordance with a number of factors including estuary
maturity, shape of the bedrock valley and estuary zonation.
• The adaptive capacity of an asset within an estuary can be guided by the natural occurrence, or
absence, of depositional shorelines within an estuary (e.g. mangrove, saltmarsh and intertidal
flats), which indicates the sediment budget of the estuary over geological timescales.
The paper applies its morphological assessment methodology to two estuaries in NSW and
highlights their likely differences of response and impacts due to SLR. The paper also provides a
summary of predicted changes to wetland vegetation at a mangrove-saltmarsh site in Minnamurra
estuary.
2.3.1.5 Anticipated Response Coastal Lagoons to Sea Level Rise
The Haines (2008) paper provides information regarding the anticipated response of coastal
lagoons to SLR.
A number of relevant points from the paper include:
• Coastal lagoons, or ICOLLs, are a common feature on the south-east coast of Australia
(particularly in NSW). Their environmental processes have evolved in response to their unique
hydrological behaviour, which is dependent on both catchment and coastal processes and
inputs. Of most significance to the structure and function of coastal lagoons is the condition of
its ocean entrance. When open, the entrance allows for regular tidal exchange and oceanic
flushing of the lagoon. When closed, however, the lagoon becomes a ‘terminal lake’ and
captures and retains 100% of all catchment inputs.
• The entrance processes of coastal lagoons, comprising the scouring or breakout stage, followed
by berm rebuilding and eventual closure, are dependent on dominant coastal processes. Long
term sea level rise is expected to have a significant impact on the entrance processes of coastal
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lagoons, which will subsequently have a cascading effect on most other environmental
processes within these naturally sensitive and unique waterways.
• An increase in mean sea level will result in an upward and landward translation of ocean beach
profiles. With respect to coastal lagoons, a sea level rise will cause the entrance sand berm to
move inland and to build up to a higher level relative to local topography. The increase in berm
height is expected to match the increase in sea level rise, given that the berm is built primarily
by wave run-up processes.
• Elevated water levels within coastal lagoons, as a consequence of higher entrance berm levels,
or higher tide levels, will potentially result in a landward migration of fringing lagoon vegetation.
If vegetation communities cannot easily migrate upslope, due to obstructions or topography,
then the vegetation communities may be lost altogether.
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3 Estuary Inundation Modelling
The impact of SLR on areas within the Bellingen Shire LGA has been assessed by modelling a
range of design tidal inundation events on the three estuaries located in the LGA. The existing
TUFLOW flood model of the Bellinger and Kalang River was reviewed, updated (where necessary)
and adopted for use in determining design tidal inundation levels and extents for current and future
SLR conditions. For the smaller Dalhousie Creek and Oyster Creeks ICOLLs, a bathtub approach
was used to determine design tidal inundation extents.
Details of the model review, development of design boundary conditions and inundation modelling
results is presented in the following sections.
3.1 Bellinger and Kalang River Due to the size and wide meandering channels of the Bellinger and Kalang River system, a
numerical flood model was required to determine flood levels and extents due to existing and future
(i.e. SLR) tidal inundation processes for a range of design events. The model was used to
investigate SLR scenarios including MSL of 0.0, 0.4, 0.7, 0.9 and 1.4 m AHD.
For each SLR scenario, four design events were considered, including:
• Mean High Water Spring;
• Highest High Water Spring Solstices (i.e. approx. King Tide);
• 1:20 year (5% AEP); and
• 1:100 year (1% AEP).
3.1.1 Description and Review of Existing Flood Model
BSC provided an existing TUFLOW flood model of the Bellinger and Kalang River system for use in
the SLR study. The model was developed by WMA water on behalf of Council and the Roads and
Maritime Service (RMS) to investigate the impacts of the proposed upgrade of the Pacific Highway
across the floodplain (refer to Section 2.2.1). A description and review of the existing flood model is
provided below.
Model Software Review
TUFLOW is a hydrodynamic model developed by BMT WBM that provides one-dimensional (1D)
and two-dimensional (2D) solutions of the free-surface flow equations to simulate flood and tidal
wave propagation. TUFLOW is used by over 500 organisations in 16 countries primarily for flood
modelling studies and has been commercially available since 2004 (www.tuflow.com). The
software is ideally suited to applications such as the current SLR study.
Model Extent Review
The model extents are presented in Figure 3-1 and include:
• Upstream to Bellingen Bridge (Lavenders Bridge) on the Bellinger River;
• To 2.5 km past the Brierfield Bridge on the Kalang River; and
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• Downstream to the Pacific Ocean.
The modelled extents are appropriate for tidal inundation modelling and no ‘glass walling’ (caused
by a lack of floodplain definition) was observed at the model boundaries.
Model Bathymetry Review
A range of topographic information is used by the model including:
• Airborne Laser Scanning (ALS) ground levels, collected as part of the Land and Property
Management Authority’s Coastal capture program (the actual survey date is not reported but it
is sometime before January 2012);
• Hydrosurvey collected by OEH between September and November 2008 of the estuary sections
of the Bellinger River, Kalang River and Pickets Creek; and
• Culvert and structure details based on an RTA culvert database.
The model review indicates that these data sets are suitable for use in the SLR study, however, it
appears that a number of culverts under the Northern Railway and Hungry Head Road (to the west
of Urunga Lagoon) were not included in the model.
Model Mesh Review
A Digital Elevation Model (DEM) of the model mesh was generated and compared favourably to
the raw ALS and hydrosurvey data, indicating that appropriate mesh elevations have been used for
the existing topography. The selection of a 15 metre by 15 metre grid for the 2D model domain is
appropriate to represent larger channels, flow paths and topographic features. The use of model
elevation modification (referred to a ‘z-lines’) has been used appropriately to represent several sub-
grid features including the crest of the breakwaters and the crest of the Pacific Highway. 1D
channels have been used appropriately for the upper Kalang River and for Boggy Creek to better
represent the channel conveyance in areas where the 2D grid resolution is unable to adequately
represent the channel profile (refer to Figure 3-1).
A check of ‘glass-walling’ to ensure that all the floodplain had been included revealed only a small
(insignificant) reduction in floodplain width occurred on the northern extent of the model, where a
small approximately 150 metre section of a valley near Pine Creek State Forest was excluded from
the model. Given the floodplain is approximately 3 km wide in this area this minor error will have an
insignificant impact on inundation results.
Model Roughness Review
The magnitude and spatial variation of model roughness is presented in WMA (2012) and
reproduced in Figure 3-1. A review of the model roughness values adopted by the model indicated
they are suitable for use in the SLR study.
Model Structure Review
A range of structures were included in the hydraulic model. Structures in the 2D domain have been
modelled using appropriate values to represent hydraulic losses or sub grid flow constrictions. A
number of culverts have been appropriately represented as 1D elements linked into the 2D domain.
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With the exception of culverts omitted under the Northern Railway and Hungry Head Road (to the
west of Urunga Lagoon) it appears that all structures have been appropriately modelled.
Model Parameter Review
All adopted parameters (i.e. turbulent mixing parameters) are within the usual range adopted for
hydrodynamic modelling of an estuary.
Tidal Calibration Review
The achieved calibration of the TUFLOW flood model is presented in WMA (2012) and summarised
in Section 2.2.1 of this report. It is important to note that the model has only been calibration to
match observed fluvial events and no specific calibration to a period of typical tides or storm surge
event has been undertaken. The time-series of observed and modelled water levels for the fluvial
calibration event presented in WMA (2012) include short periods of time prior to the flood arriving
which indicate the model is able to match the timing of observed tides. However, the model tends
to under-estimate the level of the observed tides which is likely to be due to an underestimate of
river base flow.
The lack of an appropriate tidal calibration reduces the level of certainty associated with the
prediction of absolute flood levels for the given design events. However, despite the lack of tidal
calibration, the model will be suitable for determine the relative changes to tidal inundation events
in the study area.
3.1.2 Required Updates to Flood Model
A number of minor model updates were required to improve the existing TUFLOW flood model to
increase its suitability for use in the tidal inundation assessment. Improvements to the mode
included:
• Reducing the model extent upstream of Bellingen to reduce a model instability that occurred
during low flow conditions;
• Improvement of water lines along Boggy Creek to improve the presentation of mapped output;
• Inclusion of flow paths to represent culverts under the Northern Railway and Hungry Head Road
(to the west of Urunga Lagoon). It should be noted that as no survey data were available (i.e.
dimensions and inverts of the structures), flow paths are only approximate and are provided to
ensure connectivity to all areas of potential tidal inundation are represented in the model;
• Improvement of the 1D-2D connection along the Upper Kalang to reduce a minor model
instability;
• Removal of minor catchment inflows / base flow applied to the upstream boundary of the
Bellinger River and Kalang River; and
• Adjustment of small patches of drain or beach where the elevation was below 0.9 m AHD to
remove wet cells due to the assignment of an 0.9 m AHD initial water level required for the
0.9 m SLR scenario.
It should be noted that all of these updates are minor in nature and will not greatly affect model
predictions of the WMA (2012) flood model.
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Figure 3-1 Tuflow Model Setup
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3.1.3 Development of Tidal Boundary Conditions
The aim of the current study was to determine the estuarine inundation extent for a range of design
ocean events including the spring tide, king tide, 20-year ARI and 100-year ARI event as defined in
Table 3-1. The adopted values of peak level were agreed upon after consultation with OEH and
BSC. Peak levels for the spring and king tide are based on tidal planes analysis of Coffs Harbour
data presented in MHL (2012).
Adopted peak ocean levels for the 20-year ARI and 100-year ARI events are lower than the
DECCW (2010) guidelines which provide recommended levels for the open coast but not for deep
river entrances such as that present in the study area. Wave setup acts to increase the still water
level (SWL) at the shore line due to the conversion of the wave’s kinetic energy into potential
energy as the wave breaks in the surf zone which is further explained in Appendix A.
The adopted peak levels are 0.5 metres lower than that provided for the open coast because the
estuary mouth is partially trained on the southern side and channel depths are moderately deep,
and so experiences considerably less wave setup than a shallow unprotected location as described
in Hanslow and Nielsen (1992) and Tanaka and Tinh (2008).
Table 3-1 Peak Offshore Ocean Levels Adopted for Be llinger-Kalang River Estuary
Design Event Peak Level (m AHD)
Comment
Spring tide 0.69 This represents a typical tidal case as would be observed many times each month. The adopted value is Mean High Water Spring (MHWS) for Coffs Harbour.
King tide 1.08 This represents a less typical tidal case as would only be observed several times each year. The adopted value is Mean Higher High Water Solstice Spring (MHHWSS) for Coffs Harbour.
20-year ARI 1.60 This peak tidal level is expected on average to be exceeded once every 20 years and would occur due to a major storm event. Alternatively, this peak water level event can be interpreted as having a 5% chance of occurring in any given year. The adopted value is based on a 0.9 m AHD high tide, 0.4 m storm surge and 0.3 m wave setup.
100-year ARI 2.10 This peak tidal level is expected on average to be exceeded once every 100 years and would occur due to a major storm event. Alternatively, this peak water level event can be interpreted as having a 1% chance of occurring in any given year. The adopted value is based on a 0.9 m AHD high tide, 0.6 m storm surge and 0.6 m wave setup.
The predicted inundation extent for each of these four (4) design events was determined for the
five (5) different values of mean sea level including 0.0, 0.4, 0.7, 0.9 and 1.4 m AHD.
The selected design spring tide (as presented in Figure 3-2) is a seven (7) day period of predicted
tides from the 27th September, 2008 that closely matches the adopted design spring tide peak
water level presented in Table 3-1. The 0.4, 0.7, 0.9 and 1.4 m SLR time-series were calculated by
adding 0.4, 0.7, 0.9 and 1.4 metres to the predicted (MSL = 0 m AHD) tide.
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The selected design king tide (as presented in Figure 3-3) is a seven (7) day period of predicted
tides from the 10th December, 2008 that closely matches the adopted design spring tide peak water
level presented in Table 3-1. The 0.4, 0.7, 0.9 and 1.4 m SLR time-series were calculated by
adding 0.4, 0.7, 0.9 and 1.4 metres to the predicted (i.e. MSL = 0 m AHD) tide.
Figure 3-2 Design Spring Tides
The design tide time-series for the 20-year and 100-year ARI events is based on seven (7) days of
predicted tides from the 25th December 2008 which include a 'high spring tide’ with a 0.91 m AHD
peak high water. A sinusoidal (cosine) storm surge with a four day (4) duration, was applied to this
design tide so that the peak high water is raised to meet the adopted design conditions as
presented in Figure 3-4.
The 0.4, 0.7, 0.9 and 1.4 metre SLR time-series were calculated by adding 0.4, 0.7, 0.9 and
1.4 metres to the present day (i.e. MSL = 0 m AHD) tide. An example of this is presented in Figure
3-5 for the 100-year ARI time-series. A summary of peak offshore water levels is presented in
Table 3-2.
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
0 24 48 72 96 120 144 168
Time (Hours)
Tide
Lev
el (
m A
HD
)
Spring SLR 0.0
Spring SLR 0.4
Spring SLR 0.7
Spring SLR 0.9
Spring SLR 1.4
Bellingen Shire Estuary Inundation Mapping 26 Estuary Inundation Modelling
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Figure 3-3 Design King Tides
Table 3-2 Peak Offshore Tide Levels for Five SLR Sc enarios
Design Event 0.0 m MSL
+0.4 m MSL
+0.7 m MSL
+0.9 m MSL
+1.4 m MSL
Spring tide 0.69 1.09 1.39 1.59 2.09
King tide 1.08 1.48 1.78 1.98 2.48
20-year ARI 1.60 2.00 2.30 2.50 3.00
100-year ARI 2.10 2.50 2.80 3.00 3.50
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
0 24 48 72 96 120 144 168
Time (Hours)
Tide
Lev
el (
m A
HD
)
King SLR 0.0
King SLR 0.4
King SLR 0.7
King SLR 0.9
King SLR 1.4
Bellingen Shire Estuary Inundation Mapping 27 Estuary Inundation Modelling
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Figure 3-4 Design Tides for 20 and 100yr ARI Events
Figure 3-5 100-year Design Tides
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
0 24 48 72 96 120 144 168
Tide
Lev
el (m
AH
D)
Time (Hours)
100 Year Design Tide
20 Year Design Tide
100 Year Design Surge
20 Year Design Surge
Predicted Design Tide
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
0 24 48 72 96 120 144 168
Time (Hours)
Tide
Lev
el (
m A
HD
)
100yr SLR 0.0
100yr SLR 0.4
100yr SLR 0.7
100yr SLR 0.9
100yr SLR 1.4
Bellingen Shire Estuary Inundation Mapping 28 Estuary Inundation Modelling
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As the aim of the study was to determine the impact of SLR on changes to tidal inundation, the
model was run without high ‘design event’ fluvial inflows. For the 100-year and 20-year ARI design
tides events, fluvial inflows of 4800 ML/day and 2000 ML/day were adopted for the Bellinger and
Kalang River inflows which represent an approximate 5 percent exceedance discharge condition.
For the king tide and spring tide design tides events, fluvial inflows of 1000 ML/day and
400 ML/Day were adopted for the Bellinger and Kalang River inflows which represent an
approximately 10 percent exceedance discharge condition which is a typical high baseflow
condition.
3.1.4 Tidal Inundation Model Results and Extents
The revised Tuflow flood model was used to determine tidal inundation for twenty (20) design runs
including four (4) design events (spring tide; king tide; 20 yr ARI; and 100 yr ARI) for five (5)
different SLR scenarios 0.0, 0.4, 0.7, 0.9 and 1.4 m AHD.
Grid output of peak water levels and depths were obtained from each of the 20 model runs which
were used to create design flood inundation extents (see Appendix B), a summary of peak water
levels for each simulation as presented in Table 3-3, and long section plots of peak water level
profile for the Bellinger River (Figure 3-7 to Figure 3-10) Kalang River (Figure 3-11 to Figure 3-14).
A map of the long section profiles and reported locations is presented in Figure 3-6.
3.1.5 Comparison of Tidal Inundation to Fluvial Flooding
A comparison of peak tidal inundation levels to existing design fluvial flood peak levels indicates
that even with SLR, flood risk along the river is likely to be dominated by catchment derived flood
events. From Table 2-2 we can see that a 5-year ARI flood event will produce a peak at Urunga
and Repton of 1.98 m AHD and 2.39 m AHD respectively. Comparing those values to tidal flood
peaks presented in Table 3-3 reveals that even with 1.4 metre of SLR, a spring tide is still below
the current 5-year ARI flood level. Further examination also shows that it would take a SLR of
between 0.9 metres and 1.4 metres before a King Tide event would produce estuarine flooding
worse than the current 5-year ARI flood event.
Similarly, from Table 2-2 is it apparent that the current 100-yr ARI flood event will produce a peak
at Urunga and Repton of 3.29 m AHD and 4.57 m AHD respectively. Comparing those values to
tidal flood peaks presented in Table 3-3 reveals that even with 1.4 metres of SLR, a 100-year ARI
design tide is still below these levels.
Bellingen Shire Estuary Inundation Mapping 29 Estuary Inundation Modelling
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Figure 3-6 Reported Peak Water Level Locations and Long Section Profiles
Bellingen Shire Estuary Inundation Mapping 30 Estuary Inundation Modelling
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Table 3-3 Summary of Peak Tidal Water Levels (m AHD ) for Bellinger and Kalang Rivers
Design Event
Entrance Bellinger River Kalang River
Offshore Confluence Mylestom Repton Pacific Hwy (Bellinger) Fernmount Bellinger
Bridge Urunga Lagoon Urunga
U/S Newry Island
Picket Hill
Creek
Martells Rd (U/S Kalang)
Brierfield Bridge
Bed Level -4.54 -1.24 -2.31 -0.67 -2.50 -1.40 -1.51 -0.19 -1.10 -1.50 -2.54 -3.43 0.31
Spring 0.0mSLR 0.69 0.56 0.57 0.59 0.61 0.64 0.81 0.36 0.54 0.57 0.59 0.61 0.65
Spring 0.4mSLR 1.09 0.98 1.00 1.01 1.03 1.07 1.16 0.99 0.98 1.02 1.04 1.06 1.08
Spring 0.7mSLR 1.39 1.30 1.31 1.33 1.35 1.39 1.46 1.31 1.29 1.33 1.34 1.36 1.38
Spring 0.9mSLR 1.59 1.50 1.51 1.53 1.54 1.58 1.64 1.51 1.49 1.51 1.51 1.53 1.54
Spring 1.4mSLR 2.09 1.98 1.98 2.00 2.01 2.05 2.13 1.99 1.96 1.95 1.95 1.97 1.98
King 0.0mSLR 1.10 0.93 0.93 0.95 0.97 1.02 1.12 0.94 0.90 0.95 0.97 1.00 1.02
King 0.4mSLR 1.50 1.36 1.36 1.38 1.40 1.45 1.53 1.38 1.34 1.37 1.38 1.41 1.43
King 0.7mSLR 1.80 1.66 1.67 1.68 1.70 1.74 1.82 1.67 1.64 1.64 1.64 1.66 1.67
King 0.9mSLR 2.00 1.85 1.85 1.87 1.89 1.93 2.01 1.87 1.83 1.80 1.81 1.83 1.84
King 1.4mSLR 2.50 2.31 2.31 2.31 2.33 2.37 2.43 2.33 2.28 2.21 2.21 2.23 2.24
20yr ARI 0.0mSLR 1.60 1.53 1.56 1.57 1.59 1.63 2.08 1.54 1.53 1.55 1.55 1.57 1.71
20yr ARI 0.4mSLR 2.00 1.91 1.93 1.94 1.96 2.01 2.28 1.92 1.90 1.89 1.90 1.93 2.02
20yr ARI 0.7mSLR 2.30 2.18 2.19 2.21 2.22 2.25 2.44 2.19 2.17 2.13 2.14 2.17 2.25
20yr ARI 0.9mSLR 2.50 2.37 2.37 2.38 2.39 2.43 2.60 2.38 2.35 2.29 2.29 2.32 2.39
20yr ARI 1.4mSLR 3.00 2.80 2.80 2.81 2.82 2.85 2.97 2.82 2.77 2.71 2.73 2.76 2.81
100yr ARI 0.0mSLR 2.10 2.00 2.01 2.03 2.05 2.09 2.33 2.01 1.98 1.96 1.97 2.00 2.09
100yr ARI 0.4mSLR 2.50 2.36 2.36 2.37 2.39 2.42 2.60 2.37 2.34 2.27 2.28 2.30 2.38
100yr ARI 0.7mSLR 2.80 2.62 2.61 2.61 2.63 2.66 2.79 2.64 2.59 2.50 2.50 2.53 2.59
100yr ARI 0.9mSLR 3.00 2.79 2.78 2.78 2.79 2.82 2.94 2.81 2.76 2.67 2.68 2.71 2.77
100yr ARI 1.4mSLR 3.50 3.24 3.23 3.20 3.20 3.23 3.31 3.28 3.21 3.19 3.20 3.23 3.27
Bellingen Shire Estuary Inundation Mapping 31 Estuary In undation Modelling
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Figure 3-7 Bellinger River Peak Water Level Long Se ction (Design Spring Tides)
Figure 3-8 Bellinger River Peak Water Level Long Se ction (Design King Tides)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Bellinger - Spring Tide
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Bellinger - King Tide
Bellingen Shire Estuary Inundation Mapping 32 Estuary Inundation Modelling
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Figure 3-9 Bellinger River Peak Water Level Long Se ction (Design 20-year ARI Tides)
Figure 3-10 Bellinger River Peak Water Level Long S ection (Design 100-year ARI Tides)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Bellinger - 20yr ARI
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Bellinger - 100yr ARI
Bellingen Shire Estuary Inundation Mapping 33 Estuary Inundation Modelling
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Figure 3-11 Kalang River Peak Water Level Long Sect ion (Design Spring Tides)
Figure 3-12 Kalang River Peak Water Level Long Sect ion (Design King Tides)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Kalang - Spring Tide
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Kalang - King Tide
Bellingen Shire Estuary Inundation Mapping 34 Estuary Inundation Modelling
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Figure 3-13 Kalang River Peak Water Level Long Sect ion (Design 20-year ARI Tides)
Figure 3-14 Kalang River Peak Water Level Long Sect ion (Design 100-year ARI Tides)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Kalang - 20yr ARI
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0500010000150002000025000
Chainage (m)
Pea
k W
ater
Lev
el (
m A
HD
)
0 m SLR 0.4 m SLR 0.7 m SLR 0.9 m SLR 1.4 m SLR
Kalang - 100yr ARI
Bellingen Shire Estuary Inundation Mapping 35 Estuary Inundation Modelling
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3.2 Dalhousie and Oyster Creeks Due to the small relatively small size of Dalhousie Creek and Oyster Creeks hydrodynamic
modelling was not required to determine tidal inundation extents. The dynamic nature of both creek
entrances and the lack of water level measurements at either location required due consideration
to determine appropriate design conditions for these two waterbodies, which is summarised in the
following sections.
3.2.1 Background and Key Processes
Dalhousie Creek has a waterway area of 0.075 km2 and a catchment area of 6.5 km2 (although it
should be noted the presence of two large farm dams is likely to significantly reduce runoff to the
creek). A recent estimate of natural entrance opening is twice yearly.
Oyster Creek has a waterway area of 0.15 km2 and a catchment area of 16.1 km2 being
predominantly comprised of forested and cleared farming land. There are no published estimates
of natural entrance opening occurrence though it is likely to be similar to Dalhousie Creek (i.e.
about twice each year on average).
Both creeks are defined as ICOLLs (Intermittently Closed and Open Lakes or Lagoons) due to the
dynamic behaviour of their entrances and variable interaction with the ocean. The condition of an
ICOLL entrance is the result of a dynamic balance between tidal inflow and outflows, wave driven
littoral sand transport, and intermittent flood events. Within NSW, approximately 70% of ICOLLs
are disconnected from the ocean (i.e. closed) for the majority of the time (Haines, 2008). Water
levels within a closed ICOLL are influenced by changes to the berm height, catchment runoff
volumes (i.e. rainfall and catchment area), evaporation and the stage-volume characteristics of the
water body.
Both ICOLLs in the study area have entrances that are exposed to wave processes which in the
absence of significant tidal exchange or fluvial flows are able to produce significant net onshore
transport of sediment which tend to rapidly constrict the entrance and subsequently close the
ICOLL following a breakout event. Once the ICOLL is closed, the entrance berm level increases in
height due to wave run-up and aeolian (wind) processes until rainfall events produce sufficient
runoff to raise water levels to breach the berm and re-open the ICOLL naturally.
Haines (2008) reports that natural (i.e. unmanaged) maximum berm heights for NSW ICOLLs
ranges between 2 to 3 metres and is influenced by the frequency of lagoon opening which tends to
be a function of the ratio of waterway area to catchment area (i.e. for an ICOLL with a large
catchment but small waterway area, a given rain event will cause a larger rise in water level, than
would occur for an ICOLL with a smaller catchment but larger waterway area). Because both
lagoons have a large (i.e. >0.86) ratio of catchment to waterway area, they are expected to open
fairly frequently (several time per year) and hence berm building processes would be fairly limited.
3.2.2 Determination of ICOLL Design Water Levels
Due to the dynamic nature of ICOLL entrances and processes which influence water levels with
ICOLLs, a different set of design conditions (compared to that described in Section 3.1.3) to
determine potential SLR impact on Dalhousie and Oyster Creeks was required. To determine SLR
Bellingen Shire Estuary Inundation Mapping 36 Estuary Inundation Modelling
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impact for both infrastructure and ecological assets, a range of pragmatic design conditions (see
Table 3-4) were required, that reflect both the uncertainty in determining design conditions in the
absence of short of long term water level data sets, and the relative steep sides to the water ways
(which means that small changes in water level result in small changes to the inundated area).
In addition to the selection of the four design events for mapping purposes, an indication of water
level exceedance at the ICOLLs was required to better understand the potential impact of SLR on
the estuarine ecology for the two ICOLLs. The approximated water level exceedance curves for the
two sites was used to further inform the selected design levels used for the mapping of design
inundation.
Manly Hydraulic Laboratory (MHL) collects water level data for the NSW Government at a range of
estuaries and ICOLLs along the NSW coastline, however, no water level data are available for
either ICOLL for use in this study. The behaviour of ICOLLs has been examined at a range of
similar sites allowing likely water level entrance behaviour to be inferred at Dalhousie and Oyster
Creeks. The ratio of catchment area to waterway area and the degree of exposure to wave
processes are key influences of ICOLL water levels.
Of the approximately 25 ICOLLs (out of about 70 in NSW greater than hectare in surface area)
where water level records exist (MHL, 2014), two similar ICOLLs (with respect to
catchment:waterway area ratio and entrance condition) are Curl Curl Lagoon and Werri Lagoon.
Water level exceedance data (as provided in MHL (2014) for the two lagoons was averaged to
produce a single ‘design’ series of ICOLL water level exceedance (see Figure 3-15). Wainwright
and Baldock (2010) explain that increased ocean levels due to SLR will result in a corresponding
increase in ICOLL berm heights, which means that for the purposes of this assessment, ICOLL
water levels will increase in line with changes to MSL as presented in Figure 3-15 and Table 3-5.
3.2.3 Determination of ICOLL Design Flood Extents
Tidal inundation extents for Dalhousie Creek and Oyster Creek were determined using a ‘bath tub’
approach. A DEM of the two creeks based on ALS data was used in conjunction with the design
inundation levels presented in Table 3-5 was used to create tidal inundation extents. Approximate
tidal inundation extents (see Appendix B) were obtained by contouring the DEM at the adopted
peak inundation level for each SLR scenario.
Bellingen Shire Estuary Inundation Mapping 37 Estuary Inundation Modelling
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Table 3-4 Peak Ocean Levels for Dalhousie and Oyste r Creeks
Design Event
Peak Level (m AHD)
Comment
Low Lagoon Water Level
(~85% Exceedance)
0.7 This water level is likely to be exceeded approximately 85% of the time in the ICOLL and hence represents a low lagoon water level. Immediately following a lagoon breakout, the water level may fall below this level until the entrance is significantly closed or constricted at which time the water level would begin to exceed 0.7 m AHD. It is likely that the lagoon level would only be below this level for a few days to weeks in any year.
High Lagoon Water Level
(~15% Exceedance)
1.6 This water level is likely to be exceeded approximately 15% of the time within the ICOLL. Following lagoon closure, small consecutive rainfall events (and potential wave overtopping) would gradually fill the lagoon until a breakout opens the ICOLL. It is likely that the lagoon level would only be above this level for a few weeks to months in any year.
Infrequent Lagoon Water Level
(20-year ARI)
2.2 Adopted infrequent lagoon level is the suggested 5% AEP (i.e. 1 in 20-year ARI) ocean tide for ICOLLs (DECCW, 2010). Potential design components include 0.9 m AHD high tide, 0.4 m storm surge, and 0.9 m wave setup.
Rare Lagoon Water Level
(100-year ARI)
2.6 Adopted rare lagoon level is the suggested 1% AEP (i.e. 1 in 100-year ARI) ocean tide for ICOLLs (DECCW, 2010). Potential design components include 0.9 m AHD high tide, 0.6 m storm surge, and 1.1 m wave setup.
Figure 3-15 Adopted Design ICOLL Water Level Excee dance Curves
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 10 20 30 40 50 60 70 80 90 100
Time Exceeded (%)
Lago
on W
ater
Lev
el (
m A
HD
)
Design ICOLL WL 0 m SLR
Design ICOLL WL 0.4 m SLR
Design ICOLL WL 0.7 m SLR
Design ICOLL WL 0.9 m SLR
Design ICOLL WL 1.4 m SLR
Bellingen Shire Estuary Inundation Mapping 38 Estuary Inundation Modelling
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Table 3-5 ICOLL Peak Inundation Level for five SLR Scenarios
Design Event
0 m MSL
+0.4 m MSL
+0.7 m MSL
+0.9 m MSL
+1.4 m MSL
Low Lagoon Water Level
(~85% Exceedance)
0.7 1.1 1.4 1.6 2.1
High Lagoon Water Level
(~15% Exceedance)
1.6 2 2.3 2.5 3
Infrequent Lagoon Water Level
(20-year ARI)
2.2 2.6 2.9 3.1 3.6
Rare Lagoon Water Level
(100-year ARI)
2.6 3.0 3.3 3.5 4.0
Bellingen Shire Estuary Inundation Mapping 39 Estuary In undation Risk Assessment
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4 Estuary Inundation Risk Assessment
The estuary inundation modelling results presented in Section 3 are used here to make an
assessment of the land and assets (including water, sewer, stormwater and roads) that are likely to
be impacted by periodic storm events, under present and future SLR scenarios. To assist with the
interpretation of ecological impacts outlined in Section 6, the risk assessment also considers
inundation of vegetation communities, habitats and other features of biodiversity significance
covering areas within and adjacent to the predicted inundation area.
The process outlined below is consistent with that applied to the Bellingen Coastal Zone
Management Study (CZMS) for the open coastal areas (BMT WBM, 2014a). By utilising the same
methodology, the outcomes can be more easily integrated within the outcomes of the CZMP (BMT
WBM, 2014b) at a later stage than if an alternate risk methodology was applied.
4.1 Application of a Risk-Based Framework A risk-based framework is a robust methodology for dealing with consequences that are uncertain
or have limited data, or for impacts with uncertain timeframes. This approach is therefore
particularly applicable to coastal hazards impacts and the impacts of predicted sea level rise,
where there is considerable uncertainty regarding when and if impacts will manifest. Uncertainties
associated with future climate change present huge challenges to local government and the wider
community, who need to consider and manage future risks. Decisions made today are likely to
have ramifications for up to 100 years or more (depending on the type and scale of development),
and so consideration of an extended timeframe is essential, even though risks may not manifest for
several decades.
The risk assessment process is adapted from the Australian Standard Risk Management Principles
and Guidelines (AS/NZS ISO 31000:2009), as described below and presented schematically in
Figure 4-1. The use of a risk-based approach for managing coastal hazards such as SLR
inundation is a requirement of the latest CZMP guidelines, and accords with current international
best practice for natural resource management as follows:
• Identify the Risk – the risk arises from estuary inundation during high tides combined with
storms and sea level rise. The inundation hazard was estimated for the Bellinger-Kalang
Estuary in Section 3 and is presented as hazard maps in Appendix B.
• Analyse the Risk – estuary inundation is the event to be analysed through risk management. In
this case, both likelihood and consequence of the hazard needs to be analysed. The
combination of likelihood and consequence defines the overall level of risk which are
categorised as extreme, high, medium or low.
The likelihood of risk is related to the extent of the estuary inundation hazard, now and in the
future. The likelihood of estuary inundation at the immediate, 2050, 2100 timeframes is defined
in Section 4.2.
Bellingen Shire Estuary Inundation Mapping 40 Estuary Inundation Risk Assessment
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Figure 4-1 Risk Management Framework (ISO 31000:20 09) adapted to Coastal Zone Management
Establishing the context What are our objectives for Coastal Zone Management?
Com
mun
icat
ion
and
Con
sulta
tion
S
take
hold
er a
nd C
omm
unity
Lia
ison
Mon
itorin
g an
d R
evie
w
Are
we
mee
ting
our
Per
form
ance
Indi
cato
rs?
Risk Assessment
Risk Identification What are the built, natural and community assets at risk from coastal hazards?
Risk Analysis What are the likelihood and the consequence of each coastal risk? What is the level of risk (high, medium low)?
Risk Evaluation What is a tolerable level of risk? Are there controls / mitigating actions already in place?
Risk Treatment Options What management strategies can we use to reduce the level of risk to a tolerable level? What are the costs and benefits of the strategies? At what trigger level do we implement the strategies?
Implement Management Strategies
Bellingen Shire Estuary Inundation Mapping 41 Estuary Inundation Risk Assessment
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The consequence of the risk relates to the impact of the hazard upon the land and existing and
future assets, including the aesthetic, recreational, ecological and economic values associated
with the estuary. A formal Risk Assessment Workshop with stakeholders to assess the
consequence of coastal hazards was conducted as part of the Bellingen CZMS. The outcomes
of that workshop are detailed in Appendix D of BMT WBM (2014) and are summarised in
Section 4.3.
• The consequence and likelihood were combined (using Geographical Information System (GIS)
processing) to determine the level of risk for assets and land in the study area. The key output
of the risk assessment is a register of estuary assets and their level of risk for planning
timeframes which is summarised in Section 4.5 and tabulated in Appendix C.
• Evaluate the Risks – the level of risk that is deemed acceptable, tolerable and intolerable have
been adopted from that defined in the Bellingen CZMS (2014). The evaluation criteria define the
intolerable risks that must be treated as a priority and to which management effort shall be
directed, which is discussed further in Section 4.4.
• Treat the Risks – the process of developing management options is directly related to reducing
or eliminating intolerable risks where possible. Tolerable (low) risks can be flagged for
monitoring, with no further resources necessary. Management options can be designed to
reduce the likelihood of the risks (e.g. development controls), or reduce the consequence of the
risk (e.g. emergency management to reduce the consequence of inundation) or both.
Management options first need to be technically viable for the study area. A triple bottom line
(social, economic and environmental) cost benefit analysis is then used to determine which of
the risk treatments will provide the greatest benefit (relative to cost) in treating the highest
priority risks. Management options are mentioned briefly in Section 4.5.
For existing development, the timeframes over which hazards may manifest is uncertain and so
a trigger for implementing the options has been flagged. Setting triggers ensures the
management option and associated resources are not utilised until it is absolutely necessary to
do so, which is particularly important for difficult and costly, but necessary, options. This is
described further in Section 4.6.
Implement Management Strategies (Risk Treatments) – the CZMP provides the forum
detailing how the recommended management options (risk treatments) shall be implemented
(costs, timeframes, resources) and funded. The outcomes of this study have the potential to be
integrated within the Bellingen Coastal Zone Management Plan at a later stage.
4.2 Likelihood of Estuary Inundation
4.2.1 Likelihood Scale
The hazard definition process is suited to defining the ‘likelihood’ or probability of occurrence of the
inundation hazard. A scale of ‘likelihood’ or the probability of occurrence for a hazard impact based
upon the Australian Standard for Risk Management (AS/NZS ISO 31000:2009) and its companion
document (HB 436:2004) was derived, as given in Table 4-1. The timeframes over which SLR
inundation hazard probabilities were assessed is defined in Table 4-2, namely the immediate, 2050
and 2100 planning horizons, which is consistent with the CZMP Guidelines for coastal planning.
Bellingen Shire Estuary Inundation Mapping 42 Estuary Inundation Risk Assessment
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The categories were rationalised and focus was given to ‘Almost Certain’, ‘Unlikely’ and ‘Rare’
probabilities (referred to herein as ‘Almost Certain, ‘Best Estimate’ and ‘Worst Case’; see Table
4-1) for the immediate, 2050 and 2100 planning horizons. These categories are presumed to
provide a sufficient level of detail for planning purposes. As SLR projections and assessment of the
probability of hazard impacts improves into the future, it is expected that the approach to the
definition of hazard will be incorporated into future revisions of the Risk Assessment.
Table 4-1 Risk Likelihood / Probability for Coastal Hazards
Probability Description Hazard Descriptor
Almost Certain There is a high possibility the event will occur as there is a history of frequent occurrence.
Almost Certain
Likely It is likely the event will occur as there is a history of casual occurrence. Insufficient data to
define Possible There is an approximate 50/50 chance that the
event will occur.
Unlikely There is a low possibility that the event will
occur, however, there is a history of infrequent or isolated occurrence.
Best Estimate
Rare It is highly unlikely that the event will occur,
except in extreme / exceptional circumstances, which have not been recorded historically.
Worst Case
Table 4-2 Timeframes for Coastal Planning
Timeframe Coastal Hazard
Immediate Present day conditions (e.g. 2014)
2050 Expected conditions by 2050
2100 Expected conditions by 2100
4.2.2 Likelihood of Coastal Inundation
The estuary inundation hazard refers to inundation due to elevated ocean water levels during a
storm that either propagate into river or lagoon entrances or act as a tailwater level impeding
outflow, thereby elevating their upstream water level. The rationale behind the design estuary
inundation levels and their probability for all planning periods is summarised below in Table 4-3.
Bellingen Shire Estuary Inundation Mapping 43 Estuary Inundation Risk Assessment
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Table 4-3 Estuary Inundation Likelihood Summary
Probability Immediate 2050 2100
Almost Certain 1 in 20 yr storm surge and wave set
up
As per immediate As per immediate
Likely NA 1 NA 1 NA 1
Possible NA 1 NA 1 NA 1
Best Estimate (Unlikely)
1 in 100 yr storm surge and wave set
up
1 in 100 yr storm surge and wave set up + 0.4
m SLR and climate change impacts
1 in 100 yr storm surge and wave set up + 0.9 m SLR and climate change
impacts
Worst Case (Rare)
1 in 100 yr storm surge and wave set-
up
+ extreme climatic conditions (e.g.
tropical cyclone, 1 in 1000 year east coast
low)
1 in 100 yr storm surge and wave set up + 0.7 m SLR and
climate change impacts
1 in 100 yr storm surge and wave set up + 1.4 m SLR and climate change
impacts
1 NA = Not Assessed
In defining the likelihood of coastal inundation within the immediate timeframe, it was considered:
• ‘Almost Certain’ would be equivalent to a 20-year ARI event;
• ‘Best Estimate’(unlikely) would be equivalent to a 100-year ARI event; and
• ‘Worst Case’ (rare) would be equivalent to a 100-year event with the addition of an extreme
climatic condition, resulting in still water levels (excluding wave set-up) roughly equivalent to a
1000-year ARI. Such an event was estimated to add 0.2 metres to the 100-year ARI water level.
Given the potential for tropical cyclones to track further southwards due to climate change or
more extreme storms due to climate change or natural variability over the immediate to 2100
period, it is reasonable to plan for greater than expected ocean water levels in the future.
For future planning periods (2050, 2100), extreme ocean water levels will additionally include SLR,
as well as minor projected changes to storm surge and wave height. The design inundation levels
are thus:
• an ‘Almost Certain’ probability for a 20-year ARI event, without SLR, and this approach provides
a hazard level irrespective of the rate of sea level rise. This is consistent with planning advice
given in the Coastal Protection Act 1979 and related documents for defining coastal risk areas;
• a ‘Best Estimate’(unlikely) probability of a 100-year ARI event plus predicted sea level rise, plus
increased wave set-up and storm surge due to climate change; and
• a ‘Worst Case’ (rare) probability of a 100-year ARI event plus greater than predicted sea level
rise (1.4 metres by 2100), or an extreme climatic condition (e.g. a 1000-year ARI still water level
event, excluding wave set-up) plus predicted sea level rise, whichever is greatest.
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Details of modelling undertaken for the various SLR and design inundation events described above
are provided in Section 3.
4.3 Consequence of Estuary Inundation
4.3.1 Consequence Scale
The other component of risk is consequence.
The consequence of the impact from estuary inundation relates to the land and assets affected by
the predicted inundation extent. It should be noted that the impact of the hazard being assessed
within this risk assessment is periodic and temporary (unlike the impact of coastal recession which
results in the long-term permanent loss of land, or permanent inundation due to sea level rise).
A consequence scale was developed that is relevant to estuary inundation to coastal land and
assets and its effect across the entire community and the timeframe (up to 100 years) for coastal
risk planning. The consequence scale follows a triple bottom line approach, to determine the
consequence to the society and community, environment and economy.
Terminology of ‘catastrophic’, ‘major’, ‘moderate’, ‘minor’, and ‘insignificant’ was adopted for the
consequence scale, which is consistent with the terminology adopted by Standards Australia
(2004) Handbook Risk Management Guidelines Companion, which accompanies the Risk
Management Principles and Guidelines. The consequence scale adopted is shown in Table 4-4.
4.3.2 Register of Public and Private Assets Potentially Affected
A variety of coastal assets representing various land use, facilities and features (including
environmental features) of the Bellinger-Kalang Estuary study area were identified based upon GIS
processing of:
• spatial mapping of land zoning, land tenure, cadastre and aerial photography;
• mapping of stormwater assets, wastewater and water supply assets, heritage items, parks,
dune vegetation, public buildings, roads and community assets;
• information regarding assets (social, cultural, recreational, economic) from various reports; and
• details for other assets provided through discussions with Council.
The asset types identified within the study area are listed in Table 4-6. GIS layers of coastal assets
in study area were consolidated and consequence values assigned where estuary inundation is
predicted to occur. For each of the coastal assets, a consequence value was established based on
the findings of the Risk Assessment Workshop undertaken during preparation of the Bellingen
CZMS (BMT WBM, 2014). These consequence values have been mostly adopted for the present
risk assessment, with the exception of the ecological assets, which adopts a more sophisticated
consequence scale developed around the lowest tolerance value for either saltwater or inundation
(refer Table 4-5). The consequence value, assigned to each of the assets in the study area is
summarised in Table 4-6.
Bellingen Shire Estuary Inundation Mapping 45 Estuary Inundation Risk Assessment
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Table 4-4 Consequence Scale for Estuary Inundation
Consequence Society / Community Environment Economy
Catastrophic
Widespread permanent impact to community’s services, wellbeing, or culture (e.g. > 50 % of community
affected), or
national loss, or no suitable alternative sites exist.
Widespread, devastating / permanent impact (e.g. entire
habitat destruction), or loss of all local
representation of nationally important species (e.g. endangered species). Recovery is unlikely.
Damage to property, infrastructure, or
local economy > $15 million*
Major
Major permanent or widespread medium term disruption to
community’s services, wellbeing, or culture (e.g. 50 % of community
affected), or regional loss, or
Few, if any, suitable alternative sites exist.
Widespread permanent or semi-permanent impact, or
widespread pest / weed species proliferation, or semi-
permanent loss of entire regionally important habitat. Recovery may take several
years, if at all.
Damage to property, infrastructure, or
local economy >$2 million
Moderate
Minor long-term or major short-term (mostly reversible) disruption to
services, wellbeing, or culture of the community (e.g., up to 25 % of
community affected), or sub-regional loss, or
Some suitable alternative sites exist.
Significant environmental changes isolated to a
localised area, or loss of regionally important habitat in one localised area. Recovery
may take several years.
Damage to property, infrastructure, or local economy
>$250,000** - $2 million
Minor
Small to medium short term (reversible) disruption to services, wellbeing, finances, or culture of
the community (e.g., up to 10 % of community affected), or
local loss, or many alternative sites exist.
Environmental damage of a magnitude consistent with
seasonal variability. Recovery may take one year.
Damage to property, infrastructure, or local economy
>$50,000 - $250,000
Insignificant
Very small short-term disruption to services, wellbeing, finances, or
culture of the community (e.g. up to 5 % of community affected), or
neighbourhood loss, or
numerous alternative sites exist.
Minimal short-term impact, recovery may take less than 6 months, or habitat affected with many alternative sites
available.
Damage to property, infrastructure, or local economy
<$50,000
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Table 4-5 Updated Ecological Community Consequence Ratings
Ecological Community Relative
Inundation Tolerance
Relative Saltwater Tolerance
Minimum Saltwater Tolerance
Inundation Consequence
Level
Coastal Saltmarsh EEC Medium High Medium Moderate
Freshwater EEC High Low Low Major
Littoral Rainforest EEC Low Low Low Major
Lowland Rainforest EEC Low Low Low Major
Lowland Rainforest on Floodplain EEC Low Low Low Major
Mangrove High High High Minor
Sub-tropical Coastal Floodplain Forest EEC Low Low Low Major
Swamp Oak Floodplain Forest EEC Medium Medium Medium Moderate
Swamp Sclerophyll Forest EEC High Low Low Major
Table 4-6 Consequences Ascribed to Assets in the St udy Area
Asset Category / Asset Name Coastal Inundation Consequence Level
Town Centre, Residential and Rural Property
Neighbourhood / Local Centre Major
Residential Property Moderate
Rural Property Moderate
Essential Community Facilities (e.g. Hospitals) Catastrophic
Various Community Buildings (e.g. Schools, Public Hall) Major
Primary Production, Forestry and Industry
Primary Production Lots Moderate
Forestry Land Minor
Industrial Land Moderate
Infrastructure Land Minor
Transport Infrastructure
Major Roads Major
Bridges Major
Culverts Major
Minor / Local Roads Moderate
Railway Major
Other Infrastructure
Water Main Services Minor
Wastewater Infrastructure Major
Stormwater Drainage Infrastructure Moderate
Bellingen Shire Estuary Inundation Mapping 47 Estuary Inundation Risk Assessment
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Asset Category / Asset Name Coastal Inundation Consequence Level
Community Infrastructure
Holiday Parks and Reserves Moderate
Boat Ramps and Car Parks Insignificant
Public Recreation (e.g. sport grounds) Minor
Private Recreation Facilities Minor
Amenities / Blocks / Sheds Minor
Beach Access (Pedestrian & 4WD) Insignificant
Heritage
Built Items Sensitive to Flooding Moderate
Non-flooding Sensitive Items / Sites Insignificant
Landscape / Vegetation Items Minor
Cultural / Archaeological Sites Minor
Natural Assets
Beaches Insignificant
Foredune and Hind Dunes Insignificant
Creek Entrances Insignificant
National, State and Local Parks/Reserves Minor
Environmental Protection Zones Minor
Ecological Communities (low tolerance1) Major
Ecological Communities (medium tolerance1) Moderate
Ecological Communities (high tolerance1) Minor
Waterways
Rivers, Creeks, Lagoons Insignificant
4.4 Analysis of the Level of Risk Within a risk assessment approach, risk is defined as likelihood X consequence. A risk matrix
defining the level of risk from the various combinations of likelihood and consequence was
developed for the estuary inundation risk assessment, as given in Table 4-7.
As for the likelihood and consequence scales, the risk matrix differs from that used for other risk
assessments (e.g. health and safety, operational risk and so on), as it has been designed for the
timeframes and considerations involved in coastal hazard planning.
Using the risk matrix to determine the level of risk from the combination of likelihood and
consequence ascribed to the different assets, a comprehensive asset register showing the level of
risk from SLR inundation within the study area was prepared (see Appendix C). The likelihood and
consequence values were assigned in a GIS to the hazard zones and assets respectively, and then
combined to produce an overall level of risk, using the risk matrix scores in Table 4-7.
Bellingen Shire Estuary Inundation Mapping 48 Estuary Inundation Risk Assessment
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The risk register details the various assets affected by SLR inundation and the level of risk at
present, 2050 and 2100 timeframes. The level of risk forms the basis for prioritising which assets
require treatment. Recommended management options and triggers for implementation are
discussed further in Section 4.5 and Section 4.6 and respectively.
Table 4-7 Risk Matrix for Estuary Inundation
Consequence
Insignificant Minor Moderate Major Catastrophic
Like
lihoo
d
Almost Certain Low Medium High Extreme Extreme
Likely Low Medium High High Extreme
Possible Low Medium Medium High Extreme
Unlikely Low Low Medium High Extreme
Rare Low Low Low Medium High
4.5 Estuary Inundation Risks Register The register of estuary inundation risk to assets is given in Appendix C. This table highlights those
assets which are deemed to have an intolerable level of risk and should thus be prioritised for
treatment. A summary of the risk register showing the area of inundation for each asset category
and suburb for the immediate, 2050 and 2100 timeframe is shown in Figure 4-2, Figure 4-3 and
Figure 4-4 respectively.
Of all the areas at risk from coastal inundation, approximately 30% to 40% of these are deemed to
have an intolerable level of risk (i.e. high or extreme) under both present and future scenarios. As
expected, both Urunga and Raleigh are the ‘hot spot’ suburbs with the greatest areas of intolerable
risk from inundation within Bellingen Shire, due to their low lying nature and proximity to the estuary
mouth.
Other key points to note from the risk register summary charts are:
• Ecological communities are by far at the greatest risk (particularly at Urunga), with significance
occurrences of residential, rural, primary production and recreation also experiencing intolerable
levels of risk under present and future timeframes;
• Mylestom, Repton and Bellingen may experience the smallest inundation impact for the
immediate, 2050 and 2100 timeframes with the vast majority of asset categories not at risk;
Bellingen Shire Estuary Inundation Mapping 49 Estuary Inundation Risk Assessment
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• Increasing areas of residential development at Urunga may be at risk under future scenarios
compared to the immediate timeframe. Residential development at all other suburbs is not at
risk from SLR inundation for the immediate and 2050 timeframes. Some medium risk inundation
of residential development at Raleigh is however calculated for the 2100 timeframe;
• Projected SLR for the 2050 and 2100 timeframes may exacerbate the already large area of
primary production land at risk at Raleigh; and
• Forestry, primary production and rural land is typically at risk at many of the suburbs and most
susceptible to potential SLR inundation due to its proximity to the main estuary waterways.
Bellingen Shire Es tuary Inundation Mapping 50 Estuary Inundation Risk Assessment
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Figure 4-2 Summary of Estuary Inundation Risk for the Immediate Timeframe
Note: Charts show the area of inundation (ha) predicted for each asset category within suburbs of the study area
0 50 100 150 200 250 300 350
URUNGA
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rai l / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350
RALEIGH
Residential Development
Rural Landscape
Primary Production
General Industrial
Roads / Rai l / Infrastructure
Community (+ BSC) Facilities
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350
MYLESTOM
Rural Landscape
Roads / Rai l / Infrastructure
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350
REPTON
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rai l / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350
BRIERFIELD
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rai l / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350
FERNMOUNT
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rai l / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350
BELLINGEN
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rai l / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
Bellingen Shire Estuary Inundation Map ping 51 Estuary Inundation Risk Asse ssment
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Figure 4-3 Summary of Estuary Inundation Risk for the 2050 Timeframe
Note: Charts show the area of inundation (ha) predicted for each asset category within suburbs of the study area
0 50 100 150 200 250 300 350 400 450 500
URUNGA
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350 400 450 500
RALEIGH
Residential Development
Rural Landscape
Primary Production
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350 400 450 500
MYLESTOM
Rural Landscape
Roads / Rail / Infrastructure
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350 400 450 500
REPTON
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350 400 450 500
BRIERFIELD
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350 400 450 500
FERNMOUNT
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 50 100 150 200 250 300 350 400 450 500
BELLINGEN
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
Bellingen Shire Estuary Inundation Mapping 52 Estuary Inundation Risk Assessment
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Figure 4-4 Summary of Estuary Inundation Risk for the 2100 Timeframe
Note: Charts show the area of inundation (ha) predicted for each asset category within suburbs of the study area
0 100 200 300 400 500 600 700 800
URUNGA
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 100 200 300 400 500 600 700 800
RALEIGH
Residential Development
Rural Landscape
Primary Production
General Industr ial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 100 200 300 400 500 600 700 800
MYLESTOM
Rural Landscape
Roads / Rail / Infrastructure
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 100 200 300 400 500 600 700 800
REPTON
Residential Development
Rural Landscape
Primary Production
Forestry
General Industr ial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 100 200 300 400 500 600 700 800
BRIERFIELD
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 100 200 300 400 500 600 700 800
FERNMOUNT
Residential Development
Rural Landscape
Primary Production
Forestry
General Industr ial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
0 100 200 300 400 500 600 700 800
BELLINGEN
Residential Development
Rural Landscape
Primary Production
Forestry
General Industrial
Roads / Rail / Infrastructure
Community (+ BSC) Facilities
Recreation
Ecological Community
Parks, Reserves and Open Space (+ beach and dunes)
Environmental Protection Zone
Heritage
Extreme
High
Medium
Low
Bellingen Shire Estuary Inundation Mapping 53 Estuary Inundation Risk Assessment
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4.6 Triggers for Implementation It is apparent from the risk assessment that some intolerable risks are not expected to eventuate
until 2050 or 2100. In this case, implementing a management action now, particularly where the
option is difficult or costly, may be premature and cannot account for the uncertainty of when or to
what extent the hazard may actually eventuate in the future.
While a decision regarding future intent is necessary at the present timeframe for intolerable risks,
the action may not require implementation at present. Fisk and Kay (2010) provide a method for
setting triggers for climate change adaptation actions along a time continuum. The trigger points
are set to flag the ‘level of acceptable change’ where more pro-active or decisive actions must be
implemented in order to avoid an undesirable impact. The trigger setting method is demonstrated in
Figure 4-5.
Figure 4-5 Continuum Model for Climate Change Adap tion Action
Bellingen Shire Estuary Inundation Mapping 54 Estuary Inundation Risk Assessment
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A triggered approach avoids actions being implemented until it becomes necessary, with time in
the interim to improve data/knowledge of the impact, source funding, prepare approvals and
formulate designs. It also recognises that SLR / climate change impacts may not eventuate. If this
is the case, then the community has not been unnecessarily burdened by having to adopt costly
management responses. Until the trigger is reached, ‘No regrets’ options should be implemented to
reduce the need for management by future generations (e.g. reducing the intensity of development
in at risk areas). The approach should therefore be to apply ‘No regrets’ actions at the current
timeframe and to set triggers for implementing actions for existing developments.
The majority of options suggested within this study are considered to be “No regrets” options, to
assist Council in the period of acceptable risk to plan for future implementation of more substantial
actions. For options such as the Asset Management Plan and Audit of Existing Assets, it has been
recommended that a trigger be set by Council. Guidance regarding setting of triggers for estuary
inundation is given below.
Setting triggers for estuary inundation requires careful consideration of the tolerability of specific
assets to the type of inundation hazard. That is, some assets may become unusable when
inundation occurs once a year, others may remain functional with more frequent inundation. The
trigger thus needs to be specific to the asset. The trigger may then be defined as a frequency of
inundation (e.g. a certain number of times per year), which would require monitoring at individual
assets. Alternatively, the frequency may be redefined as a depth of inundation, which is best
measured and monitored via water level gauges.
Bellingen Shire Estuary Inundation Mapping 55 Estuary Ecological Modelling
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5 Estuary Ecological Modelling
In order to understand the ecological impacts of SLR, statistics on long term (i.e. annual) water
level and salinity conditions were obtained. In order to develop these statistics, a suitable estuary
(hydrodynamic) model capable of simulating a continuous longer-term period of water levels and
salinity concentration was required.
In addition to the estuary model, a catchment (hydrologic) model was required to estimate
freshwater contributions to the estuary which influence the water levels and longitudinal salinity
variations along the Bellinger and Kalang Rivers.
Development of the hydrologic inputs (catchment model) and estuary hydrodynamic model is
outlined below in Section 5.1 and Section 5.2 respectively.
5.1 Development of Hydrological Inputs
5.1.1 The Source Modelling Framework
For this study, the eWater Source Modelling Framework (herein referred to as Source)
(http://www.ewater.com.au/products/ewater-source/) was used to simulate the rainfall-runoff
processes occurring in the Bellinger Kalang River catchment (the study catchment).
Source is an application that can be used for both catchment and river modelling. Source provides
a flexible structure that allows you to select a level of model complexity appropriate to the problem
at hand and within any constraints imposed by your available data and knowledge. Users can
construct models by selecting and linking component models from a range of available options
(Delgado et al., 2012).
Source is designed to:
• Support the construction and operation of river models that mimic river behaviour. Water
resource systems can be analysed for periods that range from days to many years; and
• Allow you to construct and interrogate water and contaminant transport models to assess the
impact of future change, on parameters of interest.
Source for Catchments integrates an array of models, data and knowledge that can be used to
simulate how climate and catchment variables (rainfall, evaporation, land use, vegetation) affect
runoff, sediment and contaminants. The output can be used to offer scenarios and options for
making improvements in a catchment. Source also features a wide range of data pre-processing
and analysis functions that allows users to create and compare multiple scenarios, assess the
consequences, and report on the findings.
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5.1.2 Model setup
5.1.2.1 Overview
The Source model is based on the following building blocks:
• Sub-catchments: The sub-catchment is the basic spatial unit, which is then divided into
hydrological response units (or functional units) based on a common response or behaviour
such as land use. Within each functional unit, three models can be assigned: a rainfall-runoff
model, a constituent generation model and a filter model;
• Nodes: Nodes represent sub-catchment outlet, stream confluences or other places of interest
such as stream gauges or dam walls. Nodes are connected by links, forming a representation of
the stream network; and
• Links: Links represent the river reaches. Within each link, a selection of models can be applied
to route or delay the movement of water along the link; or modify the contaminant loads due to
processes occurring within the links, such as decay of a particular constituent over time.
The Source for Catchments (hydrological) model was configured to estimate the quantity of surface
runoff generated under existing conditions by the major subcatchments draining to Bellingen and
Brierfield, which account for approximately 82% of the total study catchment area. Estimates of
daily streamflow at those two locations were adopted to define upstream freshwater inputs to the
2D estuary model. Several smaller subcatchments (the remaining 18% of the study catchment)
were defined in the hydrological model to account for local freshwater inputs to the lower reaches
of the Estuary.
5.1.2.2 Catchment delineation and model extents
A Digital Elevation Model (DEM) with a grid resolution of 20 metres by 20 metres was used to
digitise the upstream area draining to the tidal extents of the Bellinger River and Kalang River, and
to the lower estuary / entrance. Two major sub-catchments were delineated for Bellinger River and
Kalang River as shown in Figure 5-1. Smaller local sub-catchments incorporating the area between
the two major sub-catchments and the estuary mouth were also included. The total area of
Bellinger Kalang River catchment (herein referred to as the study catchment) is 1116 km2.
Details of the major sub-catchments are presented in Table 5-1.
Table 5-1 Major Sub-catchment Details
Sub-catchment Main Stream Length (km)
Area (km 2) % Total Area
Bellinger River 76.6 661.0 59.2
Kalang River 45.7 250.9 22.5
Lower Estuary 48.0 203.9 18.3
Total 170.3 1115.8 100
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5.1.2.3 Functional units
When creating a Source catchment model, sub-catchments are divided into areas with a common
hydrologic response or behaviour called functional units (FUs), based on various combinations of
land use or cover (e.g. bushland, rural, urban), management, position in landscape (flat, hill slope,
and ridge) and/or hazard.
FUs are used to reflect the different hydrologic responses in the area of interest (Delgado et al.,
2012). Aerial imagery (Bing Maps, 2011) was used to derive a map of FUs for the study catchment.
FUs were broadly classified according to clearance of native bushland and the amount of
impervious surfaces expected within. The following broad categories were identified and adopted in
preparing the Source for Catchments model to account for differing runoff response to rainfall. The
categories include:
• Bushland – Includes areas of uncleared native bushland;
• Rural – Includes areas cleared of bushland / native vegetation but not residential development
areas. Some minor development (rural properties and local roads) expected within; and
• Urban – Includes the higher density residential and commercial development located around
key townships such as Bellingen, Urunga, Mylestom and Repton;
• Wetland – Includes low-lying wetland areas identifiable from aerial imagery such as Urunga
Lagoon, Back Creek and Boggy Creek; and
• Water – Includes the main waterway area of the Bellinger and Kalang Rivers downstream of
Bellingen and Brierfield.
The spatial distribution of the above FUs were mapped in a GIS (refer to Figure 5-2) and used as
input to the Source for Catchments model. The area of each FU within subcatchments was
automatically assigned by the model using the gridded input dataset. A summary of catchment
properties including area and the proportion of the above FUs for each sub-catchment is provided
in Table 5-2.
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Figure 5-1 Subcatchment Delineation
Bellingen Shire Estuary Inundation Mapping 59 Estu ary Ecological Modelling
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Table 5-2 Sub-catchment Properties
ID Area (km 2) Functional Units
% Bushland
% Rural
% Urban
% Wetland
% Waterway
1 661.0 91.1 8.9 0.0 0.0 0.0
2 10.56 43.7 54.6 0.0 1.7 0.0
3 21.44 47.2 49.9 0.0 0.0 2.9
4 23.93 61.7 37.1 0.0 0.0 1.2
5 42.30 60.8 33.8 4.8 0.0 0.6
6 11.90 13.4 63.6 4.1 9.8 9.1
7 4.58 8.3 70.0 6.1 14.9 0.7
8 5.90 67.6 25.4 5.5 0.1 1.4
9 9.76 4.8 25.8 16.3 31.2 21.9
10 12.28 48.2 40.6 5.0 0.7 5.5
11 11.69 81.1 15.8 0.0 0.0 3.1
12 250.9 93.4 6.6 0.0 0.0 0.0
13 4.57 74.8 21.2 0.0 0.0 4.0
14 3.86 79.5 1.3 3.4 15.8 0.0
15 20.07 99.4 0.1 0.0 0.0 0.5
16 12.88 77.1 22.1 0.0 0.0 0.8
17 8.24 76.3 22.0 0.0 0.0 1.7
Combined 1115.86 85.7 12.8 0.5 0.5 0.5
Bellingen Shire Estuary Inundation Mapping 60 Estuary Ecological Modelling
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Figure 5-2 Functional Units Used by the Catchment Model
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5.1.2.4 Rainfall-runoff model
The SIMHYD rainfall-runoff model was used to model runoff for all surface types defined in the
model. SIMHYD is a conceptual rainfall-runoff model, which is itself a simplified version of the daily
conceptual rainfall-runoff model, HYDROLOG that was developed in 1972.
The model simplifies the rainfall-runoff processes and requires input of the following variables to
perform the hydrological assessment:
• Rainfall;
• Potential evapotranspiration;
• Catchment parameters (area, % impervious and pervious areas); and
• Impervious and pervious area parameters (rainfall threshold, infiltration rates, field capacity, soil
storage depths and groundwater parameters).
SIMHYD has been widely used in Australia and was applied for generating runoff for the Murray
Darling Basin Sustainable Yields study in 2006-2008 (Delgado et al., 2012). SIMHYD model
parameters are typically derived from calibration of the SIMHYD rainfall-runoff model to streamflow
records if available for a study area. Details of the approach to model calibration are provided in
Section 5.1.2.6.
5.1.2.5 Meteorological data
The SIMHYD rainfall-runoff model estimates daily streamflow from daily rainfall and areal potential
evapotranspiration data (APET). SILO is an enhanced climate database containing Australian
climate data from 1889 (current to yesterday), in a number of ready-to-use formats (QLD
Government, 2013). Source for Catchments utilises SILO meteorological data from data drill
locations to calculate spatially weighted (catchment averaged) rainfall timeseries for each
subcatchment.
For the period between January 1900 and December 2012 (inclusive), the mean annual rainfall
(refer to Figure 5-3) and APET (refer to Figure 5-4) was estimated to be 1685 mm and 1319 mm
respectively. The 112 year data period shown includes several large rainfall events including July
1921, July 1950, February 1954 and February 2001. A summary of the meteorological data used
by the catchment model is provided in Table 5-3.
Table 5-3 Summary of Meteorological Data
Statistic Rainfall (mm)
Areal Potential Evapotranspiration (mm)
Min 0.0 0.3
25%ile 0.1 2.1
Mean 6.1 3.6
Median 1.0 3.4
90%ile 16.1 6.0
Max 416.8 8.9
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Figure 5-3 Catchment Average Rainfall used by the Catchment Model
Figure 5-4 Catchment Average APET used by the Catc hment Model
0
50
100
150
200
250
300
350
400
450
Jan-0
0
Sep-0
2
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6
Mar-19
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4
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-43
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-54
Jun-5
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Mar-60
Dec-
62
Sep-6
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8
Mar-71
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May-
79
Feb-8
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Nov-
84
Aug-8
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90
Jan-9
3
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-95
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-06
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Rai
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l (m
m/d
ay)
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Aug-3
5
Apr-38
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1
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-43
Jul-46
Apr-49
Jan-5
2
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-54
Jun-5
7
Mar-60
Dec-
62
Sep-6
5
Jun-6
8
Mar-71
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73
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9
Feb-8
2
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84
Aug-8
7
May-9
0
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3
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-95
Jul-98
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4
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-06
Jul-09
Apr-12
AP
ET
(m
m/d
ay)
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5.1.2.6 Catchment parameters
Streamflow gauging data at Station 205016 (Bellinger River at Fosters) were available for the
period August 2007 to March 2014. The stream gauge is located approximately 2 km upstream of
Bridge Street providing a record of the observed streamflow at the outlet to Sub-catchment #1 on
the Bellinger River, which is the largest of all 17 sub-catchments.
Sub-catchment #1 is predominately bushland with areas of rural landuse present along the plateau
edge near Dorrigo Mountain and Fernbrook, and cleared floodplain areas along the Bellinger River
including townships of Darkwood, Thora, Gleniffer and Bellingen. The Kalang River Sub-catchment
(#12) is also mostly bushland with some rural land use occurring along the floodplain between
Kalang and Brierfield. Daily streamflow measurements recorded at Gauge 205016 were used to
calibrate catchment parameters for the bushland and rural functional units present within the Sub-
catchment #1. Due to similarities in landuse and topography, catchment parameters derived for
Sub-catchment #1 are expected to be equally applicable to Sub-catchment #12 (the other major
inflow location to the Estuary).
When calibrating continuous rainfall-runoff models such as SIMHYD, it is important to adopt a
calibration period that is representative of a ‘wet period’ where streamflows are typically higher.
Calibration of the rainfall-runoff model to a period of higher flow provides opportunity to capture
more runoff events and hence improves the robustness of the model following calibration. For this
reason, all available streamflow data were utilised for the model calibration, which included several
large rainfall and streamflow events during 2007, 2009 and 2011/12. The calibration period
includes a period of high quality data (i.e. record was continuous with no data gaps) and the
availability of a corresponding rainfall record for the same period. Rainfall and streamflow data
used for calibration of SIMHYD are shown in Figure 5-5 and Figure 5-6 respectively.
Figure 5-5 Daily Rainfall Data (August 2007 – Dece mber 2012)
0
20
40
60
80
100
120
140
160
180
200
Aug
-07
No
v-07
Feb
-08
Jun-
08
Sep
-08
De
c-08
Mar
-09
Jul-0
9
Oct
-09
Jan-
10
Ma
y-10
Aug
-10
No
v-10
Feb
-11
Jun-
11
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-11
De
c-11
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-12
Jul-1
2
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-12
Jan-
13
Rai
nfal
l (m
m/d
ay)
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Figure 5-6 Daily Streamflow Data (August 2007 – De cember 2012)
Catchment parameters adopted for bushland and rural functional units in the Bellinger River sub-
catchment are shown in Table 5-4. Rainfall and runoff parameters for the rural functional unit is
based on the non-urban landuse category recommended in the NSW MUSIC Modelling Guidelines
(BMT WBM, 2008) which is suitable for localities with a mean annual rainfall of more than
1000 mm. The catchment parameters for bushland were estimated from calibration of the SIMHYD
model to the observed runoff volume at the sub-catchment outlet. Note: these two functional units
account for 98.5% of the total study catchment area.
Table 5-4 SIMHYD Rainfall-Runoff Parameters for Bel linger River Sub-catchment
Parameter Bushland Rural
Impervious Area
Impervious Threshold (mm) n/a n/a
Pervious Area
Pervious Fraction 1.0 1.0
Soil Moisture Storage Capacity (mm) 350 175
Rainfall Interception Store Capacity (mm) 0.5 0.5
Infiltration Coefficient 260 215
Infiltration Shape 2 2.4
Interflow Coefficient 0.50 0.1
Recharge Coefficient 0.50 0.55
Baseflow Coefficient 0.02 0.1
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
Aug
-07
No
v-07
Feb
-08
Jun-
08
Sep
-08
De
c-08
Mar
-09
Jul-0
9
Oct
-09
Jan-
10
Ma
y-10
Aug
-10
No
v-10
Feb
-11
Jun-
11
Sep
-11
De
c-11
Apr
-12
Jul-1
2
Oct
-12
Jan-
13
Str
eam
flow
(ML/
day)
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A plot of the daily runoff volume is provided in Figure 5-7 which shows a strong linear relationship
(R2 = 0.84) between the modelled runoff and observed runoff volume. Timeseries of modelled and
observed runoff volume over the calibration period is shown on Figure 5-8. The calibrated flow
duration curve presented in Figure 5-9 and the timeseries of modelled runoff volume show a good
fit between the frequency of runoff estimated by SIMHYD and the observed streamflow data at the
sub-catchment outlet. The flow duration curve also indicates that the frequency of larger runoff
events modelled by SIMHYD is consistent with the observed streamflow data. Some discrepancy
between the observed and modelled runoff is evident during the smaller more frequent events,
however, this is considered to have minimal impact on the outcomes of the modelling. These
discrepancies are most likely due to limitations of modelling baseflow. SIMHYD assumes that
baseflow from an event contributes instantly to flow at the catchment outlet.
Figure 5-7 Calibrated Daily Runoff Volume (modelle d vs observed)
y = 0.92xR² = 0.84
0
20000
40000
60000
80000
100000
120000
0 20000 40000 60000 80000 100000 120000
Mod
elle
d F
low
(M
L/da
y)
Observed Flow (ML/day)
Run 012
Linear (Run 012)
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Figure 5-8 Timeseries of Modelled and Observed Run off Volume
Figure 5-9 Calibrated Flow Duration Curve (2007 – 2012)
1
10
100
1000
10000
100000Jul-07
Oct-07
Jan-08
Apr-08
Jul-08
Oct-08
Jan-09
Apr-09
Jul-09
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w (
ML/
day)
Run 012 Gauged Flow
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0 10 20 30 40 50 60 70 80 90 100
Flo
w (
ML/
day)
Flow Percentile (%)
Gauged Flow
Run 012
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Overall, the above results indicate that a robust calibration was achieved for one of the major sub-
catchments contributing to the Bellinger Kalang River Estuary. Estimates of daily runoff volume
provided by the catchment model (refer to Section 5.1.2.6) can therefore be used with confidence
to define freshwater inputs to the estuary model for longer-term simulations of estuarine mixing
under current and projected sea level rise scenarios.
For the lower estuary sub-catchments, three other functional units are used by the catchment
model, namely waterway, wetland and urban accounting for 1.5% of the total study catchment
area. Catchment parameters for these three functional units were defined based on the expected
rainfall-runoff response and professional judgement. Catchment parameters adopted for these
functional units are shown in Table 5-5.
Table 5-5 Additional SIMHYD Rainfall-Runoff Paramet ers for Lower Estuary Sub-catchments
Parameter Waterway Urban Wetland*
Impervious Area
Impervious Threshold (mm) 0 1 1
Pervious Area
Pervious Fraction 0.0 0.75 1
Soil Moisture Storage Capacity (mm) n/a 170 320
Rainfall Interception Store Capacity (mm) n/a 1.5 1.5
Infiltration Coefficient n/a 210 200
Infiltration Shape n/a 4.7 3
Interflow Coefficient n/a 0.1 0.1
Recharge Coefficient n/a 0.50 0.2
Baseflow Coefficient n/a 0.05 0.30
* SIMHYD default values; n/a is not applicable
5.1.3 Estimation of daily Runoff Volume
The calibrated catchment model was used to estimate the daily runoff volume from the study sub-
catchments for the period between 1900 and 2012. Timeseries of the daily runoff volume estimated
at the outlet to the major sub-catchments is shown on Figure 5-10.
The timeseries of daily runoff volume for the Bellinger River sub-catchment was selected for
subsequent data analyses and defining a representative inflow timeseries for estuary modelling.
The approach and justification for the selected inflow period is discussed further in Section 5.1.4.
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Figure 5-10 Timeseries of Daily Runoff Volume (190 0 – 2012)
0
50000
100000
150000
200000
250000
300000
Jan-
00
Apr
-03
Jul-0
6
Nov
-09
Feb
-13
Jun-
16
Sep
-19
Dec
-22
Apr
-26
Jul-2
9
Nov
-32
Feb
-36
Jun-
39
Sep
-42
Dec
-45
Apr
-49
Jul-5
2
Nov
-55
Feb
-59
Jun-
62
Sep
-65
Dec
-68
Apr
-72
Jul-7
5
Nov
-78
Feb
-82
Jun-
85
Sep
-88
Dec
-91
Apr
-95
Jul-9
8
Nov
-01
Feb
-05
Jun-
08
Sep
-11
Run
off V
olum
e (M
L/da
y)
Bellinger River Subcatchment Kalang River Subcatchment Local Subcatchments
Bellingen Shire Estuary Inunda tion Mapping 69 Estuary Ecological Modelling
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5.1.4 Selection of a Representative Inflow Timeseries
A box-whisker plot of modelled streamflow for the Bellinger River sub-catchment is provided in
Figure 5-11. The plot shows that streamflow occurs all year round and that there is no clear
seasonality in the modelled estimate of daily runoff volume. Whilst the flow regime of the Bellinger
and Kalang Rivers is not seasonal (i.e. a majority of the annual runoff does not occur over a few
months), there are some months (e.g. December to May) where runoff volume is typically higher
than the other months (e.g. June to November).
Daily runoff volumes estimated by the catchment model show that the minimum daily flow is
greater in the months of March, April and December (i.e. >50 ML/day) than the remainder of the
year (<30 ML/day). The minimum daily runoff volume is least during January and greatest during
March, and the median daily flow is greater during the summer and autumn months (e.g.
December, January, February, March and April) than winter and spring months (e.g. August,
September and October). High runoff volume days (i.e. >1000 ML/day) occur during all months
although the largest runoff volumes (i.e. 200,000 ML/day or more) occur in the months of January,
February and June.
Figure 5-11 Box and Whisker Plot of Monthly Modell ed Flow for the Bellinger River Sub-catchment
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The flow duration curve of daily modelled streamflow for the Bellinger River sub-catchment is
shown on Figure 5-12. The flow duration curve demonstrates that high flows (i.e. greater than
2300 ML/day) occur infrequently (less than 10% of the time). Similarly, low flows (i.e. less than
125 ML/day) are infrequent, with flows being greater than this 90% of the time.
Figure 5-12 Flow Duration Curve for Bellinger Rive r Sub-catchment (1900-2012)
In defining an appropriate estimate of freshwater inflows to the estuary, a single year was selected
from the long-term timeseries of modelled daily runoff volume (refer to Figure 5-10) that:
• provides a steady inflow to the estuary over the year (i.e. runoff events do not occur in
succession or few months at the beginning, middle or end of the year); and
• is a realistic estimate of streamflow at the tidal limits of the estuary that could be expected
during a below average rainfall year, and without any significant fluvial (flood) events where
flows within the Bellinger and Kalang River would significantly exceed natural channel capacity
and inundate the floodplain thereby masking the potential impact of projected sea level rise on
water levels and salinity in the upper reaches of the estuary.
Using the above criterion, estimates of daily runoff volume for the year 2005 were included in the
estuary model for the assessment of sea level rise impacts on water levels and inundation, and
changes to estuarine salinity. The modelled timeseries of runoff volume for the major sub-
catchments is shown in Figure 5-13.
1
10
100
1000
10000
100000
1000000
0 10 20 30 40 50 60 70 80 90 100
Run
off V
olum
e (M
L/da
y)
Percentile
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Figure 5-13 Timeseries of Major Inflows to the Est uary (Jan 2005 to Dec 2005)
0
2000
4000
6000
8000
10000
12000
14000
Jan-
05
Jan-
05
Mar
-05
Apr
-05
May
-05
May
-05
Jun-
05
Jul-0
5
Aug
-05
Sep
-05
Oct
-05
Nov
-05
Dec
-05
Run
off V
olum
e (M
L/da
y)
Bellinger River Subcatchment Kalang River Subcatchment Local Subcatchments
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5.2 Development of the Estuary Model
5.2.1 Scope and Objectives
To assess changes to inundation frequency and depth and also salinity, longer-term continuous
modelling of the estuary waterbody was undertaken. This modelling required the development of a
two dimensional estuary model (TUFLOW-FV) to simulate the movement (hydrodynamics) and
mixing (advection-dispersion) between tidal saltwater exchange and freshwater catchment runoff.
The separate catchment model (as described in Section 5.1) was used to model freshwater
contributions to the estuary from upstream sub-catchments which influences the longitudinal
variation of salinity along the Bellinger and Kalang rivers.
Using these two models, inundation extent / depth and salinity is predicted and used as key
indicators for assessing potential ecological impacts arising from future SLR by associating the
modelled changes of water level and salinity with vegetation tolerances and expected consequence
levels (see Section 6).
5.2.2 Model Selection
A two-dimensional hydrodynamic model of the Bellinger-Kalang Estuary was developed using the
modelling software TUFLOW-FV. TUFLOW-FV is a two dimensional finite volume model code that
solves the conservative integral form of the non-linear shallow water equations (NLSWE) (i.e.
assuming that pressure varies hydrostatically with depth), including viscous flux terms and source
terms for Coriolis force, bottom-friction and various surface and volume stresses. The model is
currently fully operational as a 2-dimensional or 3-dimensional NLWSE solver.
The model software is also capable of simulating the advection and dispersion of multiple scalar
constituents (e.g. salinity, temperature) within the model domain. Bed friction is modelled using a
Manning’s roughness formulation and Coriolis force is also included in the model formulation. The
spatial domain (or study area extents) is discretised using contiguous, non-overlapping irregular
triangular and quadrilateral ‘cells’. Advantages of an irregular flexible mesh include:
• The ability to smoothly resolve bathymetric features of varying spatial scales (e.g. channels
adjacent to broad shoaled areas);
• The ability to smoothly and flexibly resolve boundaries such as coastlines; and
• The ability to adjust model resolution to suit the requirements of particular parts of the model
domain without resorting to a ‘nesting’ approach.
The flexible mesh approach has significant benefits when applied to study areas involving complex
coastlines and embayments, varying bathymetries and sharply varying flow and scalar
concentration gradients. TUFLOW-FV presently accommodates a wide variety of boundary
conditions, including water level, flow, wind, wave stress and salinity boundaries some of which are
important for the present study.
The assumption of a well-mixed water body can be adequately represented by the two-dimensional
TUFLOW-FV hydrodynamic model. Three dimensional processes driven by salinity and / or thermal
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stratification are not significant issues for this study, even though they might occur from time to time
during or immediately following a significant catchment runoff (flood) event.
Water quality and tidal flushing are influenced by currents generated from a combination of tides
and catchment (fluvial) inflows and the primary drivers influencing tidal inundation and salinity
intrusion throughout the estuary.
5.2.3 Model Geometry and Extent
The model includes the full tidal prism of the estuary up to the tidal limits of the Bellinger River near
Bellingen and the Kalang River near Brierfield. The estuary model also includes the extensive
floodplain storage and low-lying wetland situated along these major rivers we well as Urunga
Lagoon located near the mouth of the estuary.
In defining the model geometry, quadrilateral elements were used to represent the main channels
with a mesh resolution in the order 50 to 100 metre longitudinally with typically 3 to 5 elements
across the channel (i.e. elements 20 m to 40 m wide). Floodplain elements are a mixture of
triangles and quadrilaterals with a typical mesh resolution of 50 metre side length up to an
elevation of 5 m AHD.
Important sub-mesh topographical features (such as road crests, small channels or flow paths and
breakwaters) were defined in the model mesh using model z-line elements.
The geometry (mesh) and extent of the TUFLOW-FV model are shown in Figure 5-14.
5.2.4 Bathymetry
Bathymetric data are required to describe the topography of the waterway over the domain of a
numerical model such as this. Elevation data used by the existing flood model (refer to Section
3.1.1) were used to define the bathymetry of the main waterways and floodplain areas.
Elevation data used by the TUFLOW-FV model are shown in Figure 5-14.
5.2.5 Model Configuration
TUFLOW-FV was configured to account for salinity dynamics in response to river inflow, water
level variations caused by ocean tides and local catchment runoff. The model was used in 2-d
mode (i.e. key parameters were depth averaged). The influence of the Coriolis force was
calculated using latitude of -30.5°S.
TUFLOW-FV has an adaptive time-step algorithm which automatically adjusts the model time-step
to resolve hydrodynamic and advection dispersion processes. Internal and external Courant-
Friedrichs-Lewy (CFL) stability criterion values of 1.5 were adopted which resulted in typical time-
step of between 1 and 2 seconds during the model simulation.
Bed roughness is specified as a Manning’s n roughness, which is standard for many two-
dimensional numerical models. The estuary model is uncalibrated however three broad surface
roughness types, namely main channel, floodplain and offshore were defined. The distribution of
bed roughness (and the Manning’s n values) adopted by the model are shown in Figure 5-15.
Bellingen Shire Estuary Inundation Mapping 74 Estuary Ecological Modelling
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Figure 5-14 TUFLOW-FV Model Mesh and Bathymetry
Bellingen Shire Estuary Inundation Mapping 75 Estu ary Ecological Modelling
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Figure 5-15 TUFLOW-FV Manning's n Distribution
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TUFLOW-FV accounts for wetting and drying dynamically based of specified cell depths of 0.001 m
and 0.01 m respectively. The drying value corresponds to a minimum depth below which the cell is
dropped from computations (subject to the status of surrounding cells). The wet value corresponds
to a minimum depth below which cell momentum is set to zero, in order to avoid unrealistic
velocities at very low depths.
Salinity was modelled as a passive transport scalar (i.e. uncoupled from temperature and density
effects). The scalar mixing model adopted was the Elder model which calculates non-isotropic
diffusivity using coefficients of 60 (in the longitudinal direction) and 6 (in the transverse direction). A
global horizontal eddy viscosity coefficient of 0.2 was adopted. Calibration of salinity was not
undertaken for this study and as such the model parameters were selected as being typical for the
study estuary.
5.2.6 Boundary Conditions
The estuary model adopts a downstream water level boundary to represent ocean tide variations.
For this model boundary, ocean tide data measured continuously (15 minutes intervals) at the
nearest gauging site to the study area (Coffs Harbour) was used.
Timeseries of daily runoff volume from the major rivers (Bellinger and Kalang) and local
contributing sub-catchments (15 in total) were specified using the nodestring flow boundary and
cell inflow boundary options available in TUFLOW-FV. The daily runoff volume was distributed
evenly over each model time step by the model software.
5.2.7 Long-term Estuary Modelling Scenarios
The estuary model was used to estimate changes to water level/depth, inundation extents and
salinity caused by SLR over a continuous one year period to account for temporal and spatial
variability of estuarine mixing. The model scenarios investigated by the estuary ecological
modelling are summarised in Table 5-6.
Table 5-6 Long-term Estuary Salinity Modelling Scen arios
Scenario Ocean Tide Condition Catchment Inflow
Basecase Observed tidal gauging records for Coffs Harbour over a continuous one-year period.
Below average annual inflow timeseries estimated using catchment model (see Section 5.1.4).
SLR 0.4 metres Same as Basecase except that downstream ocean tide levels are raised by 0.4 metres.
SLR 0.9 metres Same as Basecase except that downstream ocean tide levels are raised by 0.9 metres.
SLR 1.4 metres Same as Basecase except that downstream ocean tide levels are raised by 1.4 metres.
A continuous one-year period was adopted for the scenario simulations. An additional one month
period was included at the beginning of each simulation to ‘warm-up’ the model and establish
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hydrodynamic conditions (e.g. momentum, tidal pumping, water levels and salinity) within the
waterbody. Freshwater flows from the upstream catchments were modelled for a below average
annual runoff year and incorporated in the estuary model as outlined in Section 5.1.4.
5.3 Estuary Modelling Results The result of long-term estuary modelling scenarios is contained in the following sections. A map of
the long sections, chainage markers and reported locations used to obtain the following results is
presented in Figure 5-16.
5.3.1 Long-section Profiles
Long-section profiles are presented for the Bellinger River and Kalang River (Figure 5-17 to Figure
5-20). A series of subplots show the envelope (minimum, 25%ile, median, 75%ile and maximum) of
water level and salinity predicted for the different SLR scenarios 0.0, 0.4, 0.9 and 1.4 m AHD.
A summary table showing the location (chainage along each long section) where median salinity
values of 1, 5, 10, 15, 20 and 30 psu are modelled to occur is provided in Table 5-7. The relative
change between the existing (0 m MSL) scenario and increased MSL scenarios is shown in
brackets.
Table 5-7 Summary of Modelled Salinity Profiles (Me dian Salinity)
Median Salinity (psu)
0 m MSL +0.4 m MSL +0.9 m MSL +1.4 m MSL
BR KR BR KR BR KR BR KR
30 2290 2800 2820 (530)
3310 (510)
3240 (950)
3880 (1080)
3660 (1370)
4610 (1810)
20 3700 3960 4260 (560)
4690 (730)
4750 (1050)
5430 (1470)
5190 (1490)
6550 (2590)
15 4270 4520 4880 (610)
5350 (830)
5350 (1080)
6120 (1600)
5990 (1720)
7390 (2870)
10 4890 5150 5540 (650)
6020 (870)
6320 (1430)
6880 (1730)
7140 (2250)
8380 (3230)
5 5770 6020 6770 (1000)
7010 (990)
7520 (1750)
8040 (2020)
8760 (2990)
9850 (3830)
1 7740 7650 9300 (1560)
8930 (1280)
10390 (2650)
10250 (2600)
11380 (3640)
12300 (4650)
BR – Bellinger River; KR – Kalang River
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Key points highlighted by water level profile results:
• Ignoring the influence of high fluvial flow events on upstream water levels, the range in water
level is greatest at the mouth of the estuary where tidal influence is most pronounced. The
maximum water level at the upstream end of the long section profile (CH20000 – CH25000) is
influenced by fluvial flow events from the upstream catchment. A step change in water level is
also shown for this part of the long section profile (most evident for the Kalang River) which is a
consequence of excluding the out of channel (floodplain storage) area in this part of the model
and should be disregarded.
• Between CH2000 and CH20000, the water profile is uniform and sufficiently downstream
(upstream) of the river inflow (tidal inflow) influences. It is this segment of the long section
profiles where the impact of SLR on water level is most significant.
• Comparing between SLR scenarios, the results show that at CH10000 (Bellinger River at
Raleigh and Kalang River near Newry Island), and with 1.4 m of SLR, the median water level of
about 1.45 m AHD would be notably greater (by approximately 0.3 metres) than the maximum
water level expected under existing tidal conditions. Of somewhat more importance, the
minimum water level at that same location with 1.4 m of SLR is 0.65 m AHD, which is 1 metre
higher than the lowest water level modelled for the existing (SLR 0 m) condition. A water level of
this magnitude would only be exceeded about 5% of the time under existing conditions, which
typically occurs during large spring or king tides.
Key points relating to salinity profiles include:
• Under existing (SLR 0 m) conditions, a median salinity of 20 psu occurs on the Kalang River
near the downstream end of Newry Island (CH4000), and on the Bellinger River near the
upstream end of Back Creek (CH3680). A maximum salinity of 5 psu occurs near Fernmount
(CH17000) on the Bellinger River and at CH14000 on the Kalang River.
• For all SLR scenarios, the profile of minimum salinity is controlled by large fluvial flow events
from the upstream catchment, resulting in freshwater conditions along the full length of the two
river systems down to the estuary mouth. The relative position of minimum salinity along the two
rivers is comparable between the different SLR scenarios;
• Of greater interest is the change in the relative position and slope of the salinity profiles between
the different SLR scenarios 0.0, 0.4, 0.9 and 1.4 m AHD. Table 5-7 shows that the ingress of
saltwater is greater along the Kalang River than Bellinger River – this is partly due to the smaller
catchment area and consequently lower river discharge draining along this reach of estuary;
and
• For the Kalang River, a median salinity of 1 psu would be situated 1.3 km, 2.6 km and 4.6 km
further upstream of the existing scenario with increases of 0.4, 0.9 and 1.4 metres to MSL
respectively. Similarly, for the Bellinger River, the median salinity of 1 psu is predicted to
migrate 1.6 km, 2.7 km and 3.6 km upstream of the existing modelled location.
Bellingen Shire Estuary Inundation Mapping 79 Estuary Ecological Modelling
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Figure 5-16 Long-term Estuary Modelling Reporting Locations and Long Section Profiles
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Figure 5-17 Long Section Profiles of Water Level f or the Bellinger River
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter
Leve
l (m
AH
D)
Chainage (m)
Existing (SLR 0.0 m)Min 75% exceedance 50% exceedance 25% exceedance Max
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter
Leve
l (m
AH
D)
Chainage (m)
SLR 0.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter L
eve
l (m
HA
D)
Chainage (m)
SLR 0.9 mMin 75% exceedance 50% exceedance 25% exceedance Max
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter L
eve
l (m
AH
D)
Chainage (m)
SLR 1.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
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Figure 5-18 Long Section Profiles of Salinity for the Bellinger River
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
Existing (SLR 0.0 m)Min 75% exceedance 50% exceedance 25% exceedance Max
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
SLR 0.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
SLR 0.9 mMin 75% exceedance 50% exceedance 25% exceedance Max
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
SLR 1.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
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Figure 5-19 Long Section Profiles of Water Level for the Kalang River
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter L
eve
l (m
AH
D)
Chainage (m)
Existing (SLR 0.0 m)Min 75% exceedance 50% exceedance 25% exceedance Max
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter L
eve
l (m
AH
D)
Chainage (m)
SLR 0.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter L
eve
l (m
AH
D)
Chainage (m)
SLR 0.9 mMin 75% exceedance 50% exceedance 25% exceedance Max
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
0500010000150002000025000
Wa
ter L
eve
l (m
AH
D)
Chainage (m)
SLR 1.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
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Figure 5-20 Long Section Profiles of Salinity for the Kalang River
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
Existing (SLR 0.0 m)Min 75% exceedance 50% exceedance 25% exceedance Max
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
SLR 0.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
SLR 0.9 mMin 75% exceedance 50% exceedance 25% exceedance Max
0
5
10
15
20
25
30
35
02000400060008000100001200014000160001800020000
Sa
linity
(psu
)
Chainage (m)
SLR 1.4 mMin 75% exceedance 50% exceedance 25% exceedance Max
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5.3.2 Cumulative Frequency Curves
Cumulative frequency curves of water depth and salinity are presented at key reporting locations,
namely Site A to Site F as shown in Figure 5-16. The reporting locations broadly correspond to
ecologically sensitive compartments in the estuary where mangroves, saltmarsh, EECs and other
significant vegetation communities typically occur. The reporting locations also correspond to sites
selected for ecological monitoring as described in Section 7.6.
For each reporting site, cumulative frequency curves are presented for the different SLR scenarios
0.0, 0.4, 0.9 and 1.4 m AHD. The cumulative frequency curves show the range and distribution of
water depth (refer to Figure 5-21) and salinity (refer to Figure 5-22) predicted by the model at each
reporting location over the one-year simulation period.
A summary of the cumulative frequency histogram charts (median water depth and salinity) is
provided below in Table 5-8.
Table 5-8 Summary of Cumulative Frequency Results
Reporting Site SLR Scenario
0 m MSL +0.4 m MSL +0.9 m MSL +1.4 m MSL
A Water depth (m) 0 0.36 0.85 1.36
Salinity (psu) 6.2 8.3 11.8 22.0
B Water depth (m) 1.2 1.3 1.3 1.6
Salinity (psu) 29.1 32.7 33.8 34.3
C Water depth (m) 1.3 1.4 1.8 2.3
Salinity (psu) 23.7 27.6 31.0 31.7
D Water depth (m) 0 0.15 0.4 0.8
Salinity (psu) 0 7.8 19.2 25.6
E Water depth (m) 1.0 1.3 1.8 2.3
Salinity (psu) 32.7 32.5 31.0 29.4
F Water depth (m) 0.3 0.3 0.3 0.7
Salinity (psu) 34.5 34.6 33.7 33.4
The estuary modelling results demonstrate that SLR will clearly alter the range and frequency of
inundation and salinity experienced at a range of sites in the estuary. Both inundation and salinity
are important indicators of potential consequences of SLR. Significant changes to the depth of
inundation and salinity will have important implications for the adaptability or susceptibility of
existing vegetation communities to such change. For example, vegetation with a low tolerance for
increased inundation and/ or salinity will be most affected by SLR and the consequence of change
is likely to be high. Even greater consequences may arise for important vegetation communities
such as saltmarsh and swamp oak which could be pressured by mangrove invasion on the
seaward side and coastal development on the landward side. In view of this, a broad assessment
of ecological impacts is provided in Section 6.5.1.
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Figure 5-21 Cumulative Frequency Curves (Water Dep th)
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Figure 5-22 Cumulative Frequency Curves (Salinity)
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6 Interpretation and Risk Based Assessment of the Ecological Impacts
The following describes the habitat and conservation value of ecological communities in aquatic,
riparian and floodplain habitats within areas predicted to be directly affected as a consequence of
the SLR scenarios described above. Potential impacts to habitats, communities and species are
considered in the context of predicted changes to inundation levels, inundation frequency and long
term salinity patterns.
6.1 Overview This ecological assessment is based on the following scope of works:
• Review inundation extent mapping generated by the modelling;
• Based on available data provided by Council, generate maps of vegetation communities,
habitats and other features of biodiversity significance covering areas within and adjacent to the
predicted inundation areas;
• Review existing information to define known or likely high value natural assets within and
adjacent to the predicted inundation area;
• Assess the likely biodiversity consequences of SLR on high value natural assets;
• Conduct a qualitative risk assessment on the impacts of SLR on freshwater aquifer levels,
freshwater wetlands and any likely saltwater intrusions or impacts on aquifer dependent
ecological communities;
• Suggest mitigation options to reduce the impact of SLR on important high value natural assets;
and
• Identify monitoring sites for ongoing assessment of geomorphic response and ecological
community change to SLR.
6.2 Methodology
6.2.1 Study Area
The study area was selected based on the estimated extent of SLR impacts as modelled and
described in preceding sections. This area is shown in Figure 6-1.
6.2.2 Mapping of High Value Natural Assets
The ecological investigations included a comprehensive desktop analysis of the flora and fauna
values with the study area. Information used in this assessment includes aerial photography
(Google 2014), vegetation mapping, searches of public databases, and reports (principally Hawkins
and Mathews, 2006; Telfer and Cohen, 2010).
Bellingen Shire Estuary Inundation Mapping 88 Interpretation and Risk Based Assessment of the Eco logical Imp acts
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Figure 6-1 High Value Natural Assets of the Bellin ger and Kalang Rivers, Floodplains and Estuaries
Bellingen Shire Estuary Inundation Mapping 89 Interpretation and Risk Based Assessment of the Eco logical Impacts
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These information sources were used to derive a list of species, communities, habitats and other
features of high biodiversity significance within areas predicted to be inundated by SLR. Whilst all
native vegetation and habitats within the study area has ecological value, habitats of highest
conservation value, referred to as high value natural assets, support species or communities listed
under the Threatened Species Conservation Act 1995 (TSC Act), Environment Protection and
Biodiversity Conservation Act 1999 (EPBC Act), Fisheries Management Act 1994, and/or are
features of high biodiversity value protected under State Environmental Planning Policies. High
value natural assets types and information sources are listed in Table 6-1.
Table 6-1 High value natural asset types and data s ources
High value natural asset type
Legislation Data Sources
Threatened and migratory species and endangered or vulnerable ecological communities listed by the Commonwealth
Environment and Protection Conservation Act 1999
• EPBC database search tool (Department of Sustainability, Environment, Population and Communities, DSEWPC 2014)
• Hawkins and Mathews (2006)
• Bellingen Vegetation Map (March 2014)
Endangered Ecological Communities (EEC’S)
Threatened Species Conservation Act 1995
• Atlas of NSW Wildlife: Office of Environment and Heritage’s database of flora and fauna records
• Hawkins and Mathews (2006)
State listed threatened species
Threatened Species Conservation Act 1995
• Atlas of NSW Wildlife: Office of Environment and Heritage’s database of flora and fauna records
State listed protected aquatic species and habitats
Fisheries Management Act 1994
• Atlas of NSW Wildlife: Office of Environment and Heritage’s database of flora and fauna records
Features protected under State Environmental Planning Policies (SEPP)
SEPP14 Wetlands, SEPP26 Littoral Rainforest
• Planning New South Wales
Protected areas for conservation purposes
Wilderness Act 1987
Marine Parks Act 1997
• NPWS and Forests NSW estate, including areas identified as Wilderness for the purposes of the Wilderness Act 1987 / Areas identified under the Marine Parks Act 1997 and areas identified as Aquatic Reserves
Critical habitat • OEH register of critical habitat in NSW website
Significant wetlands • Directory of Important Wetlands based on that used by the Ramsar Convention in describing Wetlands of International Importance http://www.environment.gov.au/water/publications/environmental/wetlands/ramsar.html
Other habitats of high biodiversity and/or conservation significance such as riparian vegetation and beach habitat.
• Aerial imagery
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Spatial data describing the distribution, extent and/or location of high value natural assets within
and adjacent to the predicted SLR inundation area were integrated into a GIS using MapInfo
software package (Version 12).
6.2.3 Biodiversity Consequences of SLR
The likely biodiversity consequences of SLR on high value natural assets were assessed based on
a review of information on known or likely ecological sensitivities to SLR related threats (i.e. altered
hydrology and salinity) and the hydrodynamic and salinity simulations. This assessment focussed
on describing implications to four 'currencies' defined in the Garnaut Climate Change Review
(species abundances, invasive species, ecosystem processes and services, and unanticipated
changes), particularly:
• Landward retreat of coastal wetlands;
• Loss of freshwater wetlands, saltmarsh and their resident species; and
• Flow-on effects to aquatic ecosystems and their functions.
The potential impacts of SLR on freshwater aquifer levels, freshwater wetlands and any likely
saltwater intrusions or impacts on aquifer dependent ecological communities was qualitatively
assessed.
6.2.4 Risk Assessment
A risk assessment was used to identify specific ecological communities and locations most at risk
from impacts of changes to inundation and salinity regime (see Section 4).
6.2.5 Monitoring Sites
Based on the available data and a ground truthing exercise, sites were identified for ongoing
monitoring of geomorphic response and ecological community change. Site selection was based
on several criteria including:
• representative of habitats predicted to be affected by SLR;
• contain high natural value assets; and
• easily accessible.
6.2.6 Assumptions and Limitations
Limitations associated with this assessment are largely a result of the reliance on publicly available
data. Some of the mapping utilised has been developed through remote sensing and the analysis
of aerial photography, which is generally associated with some degree of error due to the scale of
the images available and their interpretation. Other records (e.g. significant species) are reliant on
the identification skills of the surveyor and may be of variable quality.
It should be noted that absence of species or ecological community records does not unequivocally
determine that the species or community does not occur or utilise the site. For example, Coastal
Saltmarsh and Swamp Oak Forest communities often occur in patches <2 ha and in linear patches
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<10 metres in width. This is generally too small to map at a local (LGA wide) scale and as a result
these communities may be underrepresented in the available mapping.
6.3 Habitats and Landform of the Study Area The composition and distribution of habitats in the study area is determined by geology and
landform, hydrology, water quality and land uses. The estuarine deposits in the lower and mid
reaches within and adjacent to the tidal front support mangroves, saltmarsh and swamp oak
communities. Seagrasses occur in the shallow waters of the lower estuarine reaches. On the
floodplain, native remnant and regenerating vegetation communities are restricted to narrow or
isolated copses on lands unsuitable for agriculture i.e. prone to flooding or too steep for cultivation.
Floodplain habitats typically comprise freshwater-dominated communities including open water and
broad-leaved paperbark wetlands prone to regular inundation and waterlogging with mixed
sclerophyll communities on higher ground. Pockets of closed rainforest occur on the coastal plains,
footslopes and foothills in the upper reaches of the study area, with lowland rainforest occupying
the riverine corridors and alluvial flats.
The riparian corridor along the length of the study area is generally 0-10 metres in width and whilst
native riverine species dominate, weeds are also prevalent (Bellingen Shire Council, 2011). The
sand dunes and plains on the coast support a mix of grasslands, heath and open woodlands with
wetlands dominating the low-lying swales. Littoral rainforest occurs in sheltered habitats on the
sand dunes.
The following section describes the general geomorphic and habitat features of the Bellinger and
Kalang River reaches and Urunga Lagoon.
6.3.1 The Bellinger River - Upper Estuary
The Bellinger River Upper Estuary is a fluvially dominated reach extending from the tidal limit at
Bellingen downstream to Fernmount (Telfer and Cohen, 2010). The floodplain has a variable
topography and is generally 4 to 7 metres above mean tide level (Telfer and Cohen, 2010). The
riparian corridor, which lies adjacent to agricultural lands, is generally less than 10 metres in width
and highly fragmented. Whilst native riverine species dominate weeds are abundant (Bellingen
Shire Council, 2011). The adjacent floodplains have also been extensively cleared but areas of
Freshwater Wetland remain.
6.3.2 The Bellinger River - Mid Estuary
The Bellinger River - Mid Estuary is fluvially dominated and has variable floodplain topography
generally 2.5 to 4 metres above mean tide level (Telfer and Cohen, 2010). The riparian corridor is
in a similar condition to the upper reaches in that it has been extensively cleared and modified and
is bounded by agricultural land uses (Bellingen Shire Council, 2011). Mangroves occur as a narrow
littoral fringe.
The adjacent floodplains have also been extensively cleared for agriculture. The mid-estuary
floodplains, which are more prone to tidal influence than the upper reaches, support a mix of EEC’s
including Freshwater Wetlands and Swamp Sclerophyll Forest on the floodplain and Swamp Oak
Forest and Coastal Saltmarsh in tidally inundated areas.
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6.3.3 The Bellinger River - Lower Estuary
The Bellinger River - Lower Estuary exhibits a pronounced marine influence whilst still exhibiting a
fluvial form (Telfer and Cohen, 2010). Floodplains average 1.5 to 2.0 metres above mean tide level
(Telfer and Cohen, 2010). The riparian corridor is in a similar condition to the upper and mid
reaches in that it has been extensively cleared and modified and is bounded by agricultural land
uses (Bellingen Shire Council, 2011). The adjacent floodplains have also been extensively cleared
for agriculture but support isolated patches of Freshwater Wetlands, Lowland Rainforest (restricted
to Tuckers Island), Swamp Oak Forest and Coastal Saltmarsh. Mangroves occur as a narrow
littoral fringe.
6.3.4 The Kalang River - Upper Estuary
The far upstream fluvially dominated reach on the Kalang River exhibits variable floodplain
topography with floodplains approximately 4 m above mean tide level (Telfer and Cohen, 2010).
The riparian corridor which lies adjacent to agricultural land uses has been extensively cleared and
is generally less than 10 metres in width (Bellingen Shire Council, 2011). Whilst native riverine
species dominate weeds are prevalent (Bellingen Shire Council, 2011). Narrow fringes of Lowland
Rainforest dominate several reaches of the riparian corridor along the main channel and tributaries.
The adjacent floodplains have also been extensively cleared but Freshwater Wetlands, Swamp
Sclerophyll Forest and Lowland Rainforest remain.
6.3.5 The Kalang River Mid-Estuary
The Kalang River Mid-Estuary exhibits a pronounced marine influence whilst still exhibiting a fluvial
form (Telfer and Cohen, 2010). The floodplains have low topography averaging 2 to 3 metres
above mean tide level (Telfer and Cohen, 2010). The majority of the upstream riparian corridor is in
good condition and lies within State Forest. Narrow riparian fringes of Lowland Rainforest occur in
the upper reaches adjacent to agricultural land. The riparian corridor in the downstream section of
this reach is generally in poor condition, averaging less than 10 metres in width (Bellingen Shire
Council, 2011), and lies adjacent to agricultural land uses. Narrow riparian fringes of Swamp
Sclerophyll Forest wetland and Swamp Oak Forest woodland dominate. The floodplains adjacent
to the upper reaches are associated with agricultural lands and have been extensively cleared but
Freshwater Wetlands and Swamp Sclerophyll Forest remain. The floodplains of the lower reaches
are also associated with agricultural lands but are more tidally influenced and Swamp Oak Forest,
Coastal Saltmarsh and Freshwater Wetland have been retained.
6.3.6 The Kalang River - Lower Estuary
The Kalang River Lower Estuary includes the north and south branches of Newry Island which
represent the fluvial transition zone (Telfer and Cohen, 2010). The riparian corridor has been
extensively cleared and is generally less than 10 metres in width (Bellingen Shire Council, 2011),
but narrow fringes of discontinuous Swamp Oak Forest, Coastal Saltmarsh and Swamp Sclerophyll
Forest wetland are present. The low floodplains (averaging 1 to 2 metres above mean tide level) on
Newry Island and the adjacent mainland have also been extensively cleared for agriculture and
residential development but areas of Freshwater Wetlands, Coastal Saltmarsh and Swamp Oak
Forest are present.
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6.3.7 The Kalang River Marine Tidal Delta and Urunga Lagoon
The Kalang River Marine Tidal Delta and Urunga Lagoon include the marine-tidal zone (Telfer and
Cohen, 2010). Floodplain height is only 1 to 1.5 metres above mean tide level (Telfer and Cohen,
2010). The riparian corridor in the lower reaches is dominated by mangroves. The riparian corridor
in the upper reaches has been extensively cleared and is generally less than 10 metres in width
(Bellingen Shire Council, 2011). With the exception of Urunga Island and adjacent to Urunga
Lagoon, most of the floodplain has been extensively cleared for agriculture and residential
development with small, isolated copses of mangroves, Swamp Oak Forest, Coastal Saltmarsh
and Swamp Sclerophyll Forest. Sand masses to the east of Urunga Lagoon support a complex of
EEC’s.
6.4 High Value Natural Assets The study area supports the following high value natural assets susceptible to SLR as indicated on
Figure 6-1 and described in detail in the following sections:
• Mangroves and seagrass: protected under the Fisheries Management Act 1994;
• Coastal Saltmarsh: listed as an Endangered Ecological Community (EEC) under the
Threatened Species Conservation Act 1995 (TSC) and Vulnerable under the Environment
Protection and Conservation Act 1999 (EPBC);
• Swamp Oak Floodplain Forest: listed as an EEC under the TSC;
• Freshwater Wetlands on Coastal Floodplains: listed as an EEC under the TSC;
• Swamp Sclerophyll Forest on Coastal Floodplains: listed as an EEC under the TSC;
• Lowland Rainforest: listed as an EEC under the TSC and Critically Endangered under the
EPBC;
• Lowland Rainforest on Floodplain: listed as an EEC under the TSC and Critically Endangered
under the EPBC. Note this community is distinguished from Lowland Rainforest in that it
generally occupies riverine corridors and alluvial flats;
• Littoral Rainforest: listed as an EEC under the TSC and Critically Endangered under the EPBC.
Includes SEPP 26 Littoral Rainforests;
• Subtropical Coastal Floodplain Forest: listed as an EEC under the TSC;
• Themeda Grassland on Seacliffs and Coastal Headlands: listed as an EEC under the TSC;
• SEPP 14 Wetlands protected under the State Environmental Planning Policy 14;
• Riparian Corridor: Some areas support EEC’s but all riparian vegetation has ecological value.
• Threatened Species: Appendix D contains a detailed list of threatened species recorded from
the region and their associated habitat types within the study area.
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6.4.1 Seagrass
Seagrass beds occur in the shallow waters of Back Creek, Urunga Lagoon, and Bellinger River up
to McGearys Island and around Urunga Island and Newry Island. Consistent with other estuaries
on the NSW North Coast, seagrass in the study area is dominated by Zostera muelleri (BMT WBM,
2007). Minor fringes of Halophila ovalis also occur in Urunga Lagoon (BMT WBM, 2007).
Seagrasses provide food and shelter for many species of fish and invertebrates including those of
economic significance and are protected under the Fisheries Management Act 1994. All areas of
seagrass in the study area have a high conservation value.
6.4.2 Mangroves
Mangroves occur in low energy, inter-tidal sedimentary environments. Consistent with other
estuaries on the NSW North Coast, mangroves of the Bellinger / Kalang River estuary include
mono-specific and mixed stands of Avicennia marina (Grey Mangrove) and Aegiceras corniculatum
(River Mangrove) (BMT WBM, 2007).
Extensive clearing of wetland vegetation, drainage, flood gating and associated loss of habitat and
connectivity has resulted in significant losses of estuarine wetlands within the Bellinger River
catchment. The largest remaining mangrove forests within the Bellinger River catchment occur at
Back Creek and its backwaters. Within the Kalang River catchment, several small patches of
estuarine wetlands occur including Urunga Lagoon and near Newry Island. In the upper estuary,
extensive mangroves occur in the sheltered brackish waters of lower Picket Hill Creek adjacent to
Newry State Forest.
Mangroves provide habitat for species of fisheries value and conservation significance, and provide
a range of ecosystem services including bank stabilisation and nutrient cycling. Mangroves are
protected under the Fisheries Management Act 1994.
6.4.3 Coastal Saltmarsh
Saltmarsh provides habitat for species of fisheries value and conservation significance (e.g.
migratory waders), and is protected under the Fisheries Management Act 1994. Coastal Saltmarsh
in northern NSW is protected as an Endangered Ecological Community under the Threatened
Species Conservation Act 1995 (DEH, 2014a) and Subtropical and Temperate Coastal Saltmarsh
is listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999.
The following habitats are excluded from the EPBC listed coastal saltmarsh:
• saltmarsh occurring on inland saline soils with no tidal connection;
• isolated patches of saltmarsh < 0.1 ha;
• patches or areas of saltmarsh that contain > 50% weeds (i.e. patches must be dominated by
native saltmarsh plant species to be the ecological community);
• patches of saltmarsh (possibly senescent) within the coastal margin that are disconnected
(either naturally or artificially) from a tidal regime but were once connected. However, should the
patch be reconnected to the tidal regime (e.g. via removal of an artificial barrier, or constructing
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a pipeline under a roadway), then the patch can become part of the ecological community (i.e. if
it meets other key diagnostics and condition thresholds).
Saltmarsh occurs as isolated and discontinuous patches along Back Creek, Urunga Island and
Newry Island. Urunga Lagoon supports the largest contiguous saltmarsh community within the
study area.
Consistent with other estuaries on the NSW North Coast, saltmarsh in the study area is dominated
by a groundcover of Sporobolus virginicus, Suaeda australis, Juncus kraussii, Halosarcia indica,
Isolepis nodosa and Tetragonia tetragonoides with isolated mangrove canopy shrubs and trees
(BMT WBM, 2007).
6.4.4 Swamp Oak Forest
This community type generally consisted of mono-specific stands of Casuarina glauca but may
contain Melaleuca quinquenervia (broad-leaved paperbark) as a sub-dominant or co-dominant.
They typically occur on very poorly drained sites in adjacent to tidal waters.
The largest areas of swamp oak within the study area occur landward of the mangrove fringe of
Back Creek and its backwaters, Urunga Lagoon, Newry Island and the upper estuary waters of
lower Picket Hill Creek adjacent to Newry State Forest.
Swamp Oak floodplain forest of the NSW North Coast is listed as an Endangered Ecological
Community under the TSC Act (DEH, 2014b).
6.4.5 Freshwater Wetlands
These communities typically occur in association with Melaleuca or sclerophyll swamps and are
dominated by sedges and rushes with sparse trees and shrubs. These wetland communities may
provide habitat for significant species such as waterwheel plant (Aldrovanda vesiculosa), Green
and Golden Bell Frog (Litorea aurea), Great Egret (Ardea alba), Intermediate Egret (Ardea
intermedia), Little Egret (Ardea garzetta), Black-necked Stork (Ephippiorhynchus asiaticus), Royal
Spoonbill (Platalea regia), Japanese Snipe (Gallinago hardwickii) and Black-winged Stilt
(Himantopus himantopus).
Freshwater wetlands on coastal floodplains of the NSW North Coast are listed as an Endangered
Ecological Community under the TSC Act (DEH, 2014c).
6.4.6 Swamp Sclerophyll Forest
These communities occur on very poorly drained sites and are generally dominated by Melaleuca
quinquenervia. Other species can include Melaleuca styphelioides, M. linariifolia, M. nodosa, M.
sieberi, Casuarina glauca, Eucalyptus spp and Corymbia spp. The lower stratum is generally
absent or sparse and comprised of sedges and wet heath species with occasional rainforest
elements.
Agricultural activities across the floodplains of the study area have resulted in extensive clearing of
wetland vegetation and drainage of the floodplain however narrow copses of these communities
occur throughout the study area.
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Swamp Sclerophyll Forest provides potential habitat for the endangered swamp orchids Phaius
australis and P. tancarvilleae. In addition, they provide habitat for threatened fauna species such as
Grey-headed Flying Fox (Pteropus poliocephalus), Yellow-bellied Glider (Petaurus australis),
Regent Honeyeater (Xanthomyza phrygia), Swift Parrot (Lathamus discolor), Osprey (Pandion
haliaetus), Australasian Bittern (Botaurus poiciloptilus), Large-footed myotis (Myotis adversus),
Litoria olongburensis and Wallum Froglet (Crinia tinnula).
Swamp sclerophyll forest on coastal floodplains of the NSW North Coast is listed as an
Endangered Ecological Community under the TSC Act (DEH, 2014d).
6.4.7 Rainforests
Three rainforest communities, typified by a closed canopy, occur within the study area:
• Lowland Rainforest is the most widespread rainforest type in the study area. It is generally
associated with basalt and sedimentary rocks on the coastal plains, footslopes and foothills in
the upper reaches of the study area;
• Lowland Rainforest on Floodplain is distinguished from Lowland Rainforest in that it generally
occupies riverine corridors and alluvial flats of the study area in the mid to upper reaches of the
Kalang River; and
• Littoral Rainforest occurs on sand dunes of the study area east of Urunga Lagoon. Some
Littoral Rainforest remnants are protected under State Environmental Planning Policy 26 (SEPP
26).
All these rainforest communities are listed as EEC’s under the TSC (DEH, 2014e,f,g) and Critically
Endangered under the EPBC. All potentially support a number of threatened species such as
Acronychia littoralis (Scented Acronychia), Cryptocarya foetida (Stinking Laurel), Hicksbeachia
pinnatifolia (Red Bopple Nut), Fontainea oraria (Coast Fontainea), Ninox strenua (Powerful Owl),
Dasyurus maculatus (Spotted-tailed Quoll) and Kerivoula papuensis (Golden-tipped Bat).
6.4.8 Subtropical Coastal Floodplain Forest
These communities occur in the south-east of the study area south of Urunga Lagoon and are
associated with clay-loams and sandy loams, on periodically inundated alluvial flats, drainage lines
and river terraces on coastal floodplains. The structure of the community may vary from tall open
forests to woodlands and the most widespread trees include Eucalyptus tereticornis (forest red
gum), E. siderophloia (grey ironbark), Corymbia intermedia (pink bloodwood) and Lophostemon
suaveolens (swamp turpentine). This community may provide habitat for a broad range of
significant fauna such as Glossy Black Cockatoo (Calyptorhynchus lathami lathami), Squirrel Glider
(Petaurus norfolcensis) and Koala (Phascolarctos cinereus).
Subtropical Coastal Floodplain Forest is listed as an EEC under the TSC (DEH, 2004h).
6.4.9 Themeda Grassland on Seacliffs and Coastal Headlands
This community is listed as an EEC under the TSC (DEH, 2004i). Themeda australis is the
dominant species in this community but emergent shrubs may also occur. Individual stands of the
community are often very small and overall the community has a highly restricted geographic
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distribution comprising small, but widely scattered patches. This community lies to the south of the
study area restricted to an isolated patch less than one hectare in area and is not predicted to be
impacted by the SLR scenarios, as such this community is not considered further.
6.4.10 Riparian Corridor
The majority of the riparian corridor in the study area lies adjacent to agricultural land uses and has
been extensively cleared. It generally occurs as a narrow fringe 0 to 10 metres in width and whilst
native riverine species dominate weeds are prevalent (Bellingen Shire Council, 2011). In addition to
the presence of EEC’s, notably Swamp Oak Forest in the mid to lower reaches and Lowland
Rainforest on Floodplain in the upper reaches, riparian corridors provide important functions such
as water quality control and provide habitat for threatened species such as Koala. All riparian
vegetation in the study area has high conservation value.
6.4.11 Groundwater Dependant Ecosystems
Groundwater dependent vegetation does not rely on the surface expression of water but instead
depends on the subsurface presence of groundwater (Kuginis et al. 2012). Although rainfall is the
dominant source of water for most wetlands groundwater plays a minor to essential role in all
Australian wetlands (Hatton and Evans, 1998). Some wetlands are obligate groundwater
dependant ecosystems (GDE’s) which are dependant on groundwater, for example, swamp
sclerophyll communities, wet heathlands and sedgelands growing in swales and swamps and
subject to shallow water table levels (Kuginis et al. 2012). Other communities are facultative GDEs
which may only depend on groundwater under dry conditions, for example dry heathland on beach
ridges and dunes subject to deeper water table levels (Kuginis et al. 2012).
Broadly within the study area, vegetation and wetlands located within coastal sand aquifers are
likely to be dependent on groundwater whilst the importance of groundwater to floodplain
vegetation will depend on the nature of underlying soils and aquifer (Kuginis et al. 2012). The tidal
wetlands would depend on the flux of groundwater either directly or on groundwater fed discharge
at the mouths of the Bellinger and Kalang Rivers. The importance of groundwater discharge to the
ecosystems within the study area is poorly understood and the extent of groundwater dependency
is largely unknown. However, based on the Risk Assessment Guidelines for GDE’s in NSW
(Kuginis et al. 2012), the study area supports the following potential GDE’s:
• Non-Tidal Freshwater Wetlands: swamp forests; freshwater wetlands; freshwater lagoons;
sedgelands; swamp heath; shrub swamps;
• Tidal Wetlands: mangroves; saltmarsh; seagrass; inter-tidal sand and mudflats; tidal lagoons;
• Floodplain Communities: woodlands and open forests; rainforest;
• Coastal Dunes: sclerophyll forests/woodlands/scrubs; heath; littoral rainforest;
• Sedimentary Habitats: sand beaches; and
• Aquatic habitats: freshwater streams and rivers.
Although it is assumed many of these communities depend on groundwater, the nature of
dependency is largely unknown.
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Based on Kuginis et al. (2012), to be classed a GDE of high ecological value within the Northern
Rivers of NSW the potential GDE (or part thereof) must:
• Occur within a protected area (National Park / Marine Reserve / SEPP /DIWS /Ramsar);
• Be identified as a rainforest community;
• Support threatened/endangered species or communities;
• Be identified as Critical Habitat or Key Habitat;
• Be a high conservation value area within a Regional Conservation Plan;
• Be identified as an area of importance to biodiversity within the Northern Rivers Regional
Biodiversity Management Plan.
Figure 6-2 to Figure 6-4 show the areas of high ecological value GDE’s identified on the coastal
sands and alluvial plains of the study area (Kuginis et al., 2012). Based on the available mapping
the following EEC’s recorded in the study area are classed as GDE’s: Littoral Rainforest, Lowland
Rainforest, Swamp Oak Floodplain Forest, Swamp Sclerophyll Forest on Coastal Floodplains, Sub-
tropical Coastal Floodplain Forest, Coastal Saltmarsh and Freshwater Wetlands on Coastal
Floodplains (Kuginis et al.2012).
6.4.12 State Environmental Planning Policies
The aim of State Environmental Planning Policy 14 (SEPP 14) – Coastal Wetland, is to ensure that
coastal wetlands are preserved and protected. Approximately 260 ha of SEPP 14 wetlands occur
on the lower floodplain of the estuary. The major occurrences of SEPP 14 Wetlands in the estuary
include Urunga Lagoon, south of Urunga, west of Newry Island, Back Creek and Urunga Island.
Some Littoral Rainforest remnants east of Urunga Lagoon are protected under State Environmental
Planning Policy 26 (SEPP 26), the aim of which is to ensure that littoral rainforests are preserved
and protected.
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Figure 6-2 High Ecological Values GDE’s Bellinger- Nambucca Coastal Sands
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Figure 6-3 High Ecological Values GDE’s Coastal Be llinger Alluvial
Figure 6-4 High Ecological Values GDE’s Coastal Ka lang Alluvial
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6.5 Biodiversity Consequences of Sea Level Rise This section describes the potential implications of SLR on High Value Natural Assets based on
degree of saline intrusion and inundation only. This report does not consider the complex
interactions between ecological, geomorphological and biogeochemical processes that are likely to
occur.
6.5.1 Broad SLR Ecological Impacts
The most profound effect of climate change on estuarine habitats will probably be SLR (Lovelock
and Ellison 2007, Gilman et al. 2008, BMT WBM 2011) and the biodiversity consequences of such
an effect are described below. It is important to note that SLR represents only one component of
climate change and is linked to numerous other interacting climate change processes. Various
secondary impacts may also arise such as changes in ecosystem processes resulting from altered
fluvial flow regimes, loss of habitat connectivity, physical disturbance to habitats and species
resulting from increasing storms. It is beyond the scope of this study to present these processes in
detail.
The biodiversity consequences due to SLR can be grouped into four key ‘currencies’ as follows
(based on MacNally et al. 2008):
• Species abundances: SLR may provide favourable conditions in new areas for some species,
notably mangroves, and declines in the extent of suitable habitat for others that are intolerant of
the new environmental conditions and unable to migrate to suitable habitat (e.g. coastal
saltmarsh).
• Invasive species: Changes in environmental conditions may increase opportunities for invasive
or disturbance-dependant species, both native and exotic, to the detriment of native
communities (e.g. Phragmites invasion of coastal saltmarsh).
• Ecosystem processes and services: Trophic function and ecosystem integrity is likely to be
affected both directly, and as a secondary flow-on through changes to habitats, species
distribution and abundance, connectivity and biogeochemical processes.
• Unanticipated changes: There is a clear need for better information on the physical
characteristics of the landscape, the functioning of wetland ecosystems and the resilience of
individual species to SLR in order to make more accurate predictions. However, even with
further information, there will undoubtedly be a range of unanticipated changes that cannot be
predicted given the complexity and stochastic nature of wetland ecosystems.
At the habitat scale, SLR is expected to result in coastal inundation, increased erosion and saline
intrusion with resulting transitions in wetland communities and species composition (Trail et al.,
2011). SLR in combination with associated shoreline erosion and saltwater intrusion will result in
local losses, which may be offset by potential gains and produce an overall shift in estuarine and
freshwater wetlands (Millennium Assessment 2005). However, determining the vulnerability of
habitats to SLR and quantifying these impacts is complex and depends in part on biophysical
aspects including coastal dynamics, hydrology, water quality, saline intrusion and sedimentation. In
addition, these habitat responses will be sensitive to land uses which may influence the ability of
habitats to colonise and migrate in response to SLR.
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Based on the SLR modelling and available habitat mapping, it is predicted that SLR will impact on
the low floodplains and littoral fringe of the upper, mid and lower reaches of the Bellinger and
Kalang Rivers and the full extent of Urunga Lagoon. This is predicted to impact on a variety of High
Value Natural Assets as shown in Figure 6-5 and outlined below in the following sections.
6.5.1.1 Seagrass
The critical factors for seagrass growth are light, temperature, carbon dioxide, nutrients and
suitable substrate (Connolly, 2012). In particular, water depth, which controls the ambient light
climate, is a key control on the distribution and extent of seagrass meadows within estuaries
(Carruthers et al. 2002).
Depending on local conditions, SLR (and other climate change factors) could lead to decreased
seagrass productivity, local to large scale loss due to decreased light, and changes in species
composition and distribution (Connolly, 2012). It is expected that an increase in water depth will
result in a horizontal shift in the position of seagrass meadows, should suitable habitat be present
in newly inundated areas. SLR and other climate change processes (particularly altered rainfall
patterns) could also influence other key controls on seagrass meadow extent and community
structure. Poor water quality may also directly influence aquatic organisms within the seagrass
zone. These organisms are a key component of the estuarine food chain and any impacts on them
could influence terrestrial fauna reliant on them as a food source, such as migratory waders.
6.5.1.2 Mangroves
As mangroves grow in calm intertidal habitats with a low profile, SLR has the potential to impact on
large areas of this habitat within the study area. Mangroves have demonstrated adaptability and
resilience and are highly successful colonisers given appropriate sedimentation and hydrological
conditions. Under SLR, it is anticipated that ocean-facing mangroves will regress as a result of
inundation and upper mangrove communities will transition into locations previously occupied by
coastal saltmarsh and floodplain freshwater wetlands. Mangroves may also migrate upstream in
response to changes to tidal planes.
The extent of mangrove colonisation will be dependent on the landform and profile of the intertidal
zone. Steep bank profiles and narrow longitudinal areas of intertidal habitat in the upper reaches
are likely to restrict extensive mangrove establishment. Constructed barrages across the floodplain
may restrict expansion of mangroves with the tidal front. Coastal development in the study area
may also hinder the landward migration of mangroves and result in a loss of mangroves due to
coastal squeeze.
Quantifying the impact of SLR on mangroves is complex and depends in part on hydrology and
rates of sedimentation. Availability of suspended sediments, sediment type and water storage
capacity, rates of below-ground root growth and decomposition and sediment compaction will all
influence the rate of sedimentation in mangroves and in turn their ability to colonise (DCC, 2009). It
is generally considered that if the rate of SLR exceeds sedimentation rates there may be an overall
loss of mangrove extent (DCC, 2009). Conversely, if the rate of sedimentation in mangrove
communities exceeds SLR, then there may be an opportunity for landward retreat of mangroves
and their extent may increase or remain unchanged (DCC, 2009).
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Figure 6-5 Predicted High Value Natural Asset SLR Impacts
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Changes to mangrove health may reduce their resilience to SLR. Potential processes that could be
affected by SLR that may lead to indirect impacts to mangrove health include:
• Changes to soil salinity - which is a function of tidal inundation, rainfall, groundwater seepage
and evaporation (DCC, 2009); and
• Increased pollutant loads – due to tidal inundation of agricultural lands with potentially high
nutrient, sediment and agricultural chemical load of the floodplains. Export of sulfuric acid and
metals associated with the presence of ASS may also occur.
Whilst an influx of nutrients may assist in the incursion of mangroves into saltmarsh and wetland
areas, and mangroves are generally tolerant of poor water quality, with prolonged exposure to high
levels of pollution and in the presence of agricultural chemicals (particularly diuron), mangrove
metabolism and productivity may be compromised (MacFarlane, 2001). Poor water quality may
also directly influence aquatic organisms within the mangrove zone. These organisms are a key
component of the estuarine food chain and any impacts on them could influence terrestrial fauna
reliant on them as a food source, such as migratory waders.
6.5.1.3 Coastal Saltmarsh
Coastal saltmarsh frequently occurs on the landward side of mangroves in low energy habitats
within the high tide zone. Their distribution and composition are determined by the combination of
elevation, salinity and frequency of inundation. They are often subject to daily inundation by saline
waters at high tide with upper marsh zones only being reached by the highest tides. Coastal
saltmarsh plants are adapted to hypersaline conditions which most other vegetation cannot
tolerate. As saltmarsh grow in and adjacent to intertidal habitats with a low profile, a rise in sea
level has the potential to impact on large areas of this habitat within the lower and mid reaches of
the study area.
Similar to the response of mangroves, provided sedimentation is able to maintain surface elevation
at the same or greater rate than SLR, coastal saltmarsh would naturally migrate landwards in
response to a shift in the tidal front. However, coastal saltmarsh is particularly prone to coastal
squeeze i.e. these communities tend to occur between landward coastal development and the
impacts of SLR on mangroves on the littoral front, which may prevent landward migration of
saltmarsh as sea levels rise. Other urban and agricultural impacts, particularly the loss of
connectivity, altered sediment dynamics and increased nutrient runoff, will also reduce saltmarshes
resilience to SLR.
As discussed above, under SLR there may be a decline in water quality as a result of tidal
inundation of agricultural lands with potentially high nutrient, sediment, ASS and agricultural
chemical loads. An influx of nutrients may assist in the incursion of mangroves into saltmarsh. In
addition, prolonged exposure to high levels of pollution may compromise saltmarsh productivity and
saltmarsh vulnerability to SLR. This may also impact on benthic organisms within the saltmarsh
zone affecting terrestrial fauna reliant on them as a food source, such as migratory waders.
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6.5.1.4 Swamp Oak Forest
Swamp oak forest communities occur above the tidal limit, frequently on the landward side of
coastal saltmarsh, where the groundwater is saline or sub-saline, on waterlogged or periodically
inundated flats, drainage lines and estuarine fringes. Casuarina glauca can withstand short periods
of inundation and is tolerant of very saline conditions (Clarke and Allaway, 1996). Temporary
inundation is unlikely to cause any significant change in these communities, however, any
permanent inundation is likely to cause a retreat of the tree line from the water edge.
There is potential for the intrusion and retreat of tidal waters in areas of known acid sulfate soils to
cause acid scalds and iron staining, resulting in minor loss of swamp oak forest. This phenomenon
was experienced near Cairns where changes in site hydrology and chemistry (caused by
reintroduction of tidal inundation) lead to the reformation of pyrite and iron minerals on the soil
surface (Johnston et al. 2009). The location and size of areas that may be subject to these impacts
is not yet known, but is expected to be a small proportion of those areas (probably small
topographic hollows) affected by SLR.
6.5.1.5 Floodplain Habitats
Freshwater Wetlands and Swamp Sclerophyll Forests
These habitats are associated with periodic or semi-permanent inundation by freshwater, although
there may be minor saline influence in some. Wetland plant species have physiological limits on
the level and duration of inundation and salinity levels, and flow rates and erosion can effect
recruitment. Therefore any change in the depth, quality and duration of inundation levels within
these habitats will have an impact on their distribution and composition. Freshwater wetlands can
tolerate minor and temporary saline intrusion, however, regular inundation is likely to result in a
shift in dominance to swamp oak, mangroves and potentially saltmarsh species.
Broad-leaved paperbark (a dominant species in some of these communities) is known to tolerate
low salinity up to 8,000 µS/m (Greening Australia, 2014) with seawater being approximately
50,000-58,000 µS/m. Regular to permanent inundation with salt water would lead to reduced
growth and germination of this species, and other wetland species associated with freshwater
conditions. In this case, Casuarina glauca (which occurs in close association with Melaleuca
communities), mangroves and saltmarsh species may be favoured and become the dominant
species.
As tidal influences in low-lying terrestrial lands increase as a result of SLR there is likely to be a
landward migration of wetland communities. The rate of wetland transition will depend on
geomorphological features (such as slope, substrate and erosion and sedimentation rates),
groundwater influences, saline intrusion, inundation levels, climatic features (particularly rainfall),
land use and plant community composition. Coastal development in the study area may hinder
wetland migration and result in a loss of total extent due to coastal squeeze or lack of suitable
habitat.
Sediment trapping, carbon sequestration and nutrient cycling will all decline with a reduction in
wetland extent (DCC, 2009). This may result in higher turbidity and nutrient loading in nearshore
waters (DCC, 2009). With potential reductions in floodplain wetland habitat, loss of wetland flora
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and fauna diversity is also likely to occur as mangroves, swamp oak and potentially saltmarsh
encroach into them. This may impact on threatened species reliant on these habitats. For example
some areas of potential wetland habitat for wallum froglet may be affected by potential saline
incursion as a result of SLR. Wallum froglet has been noted breeding in ponds with salinity of 35 –
100 ppm (Simpkins et al. 2014). This species is not salt tolerant and would not remain in an area
subject to saline intrusion.
As discussed above, there is potential for the intrusion and retreat of tidal waters in areas of known
acid sulfate soils to cause acid scalds and iron staining, resulting in minor loss of habitat in
freshwater wetlands. The location and size of areas that may be subject to these impacts is not yet
known, but is expected to be a small proportion of those areas (probably small topographic
hollows) affected by SLR.
Rainforests and Subtropical Coastal Floodplain Forest
These groundwater-dependent communities generally occupy alluvial flats with rich, moist silts. As
tidal influences in low-lying terrestrial lands increase as a result of SLR, there may be direct
impacts on these communities resulting in losses in community extent and/or condition. The rate
and extent of loss and/or condition will depend on a range of factors particularly freshwater inflows
and changes to groundwater quality and depth. Any habitat transition in these communities will be
very slow due to inherently low levels of recruitment and will be dependent on availability of habitat
conditions free from fire and other threatening processes, such as weed invasion and adjacent
landuses.
6.5.1.6 Riparian Corridor
SLR may result in localised changes in sites of erosion and accretion along the main channel and
tributaries, which would impact on the riparian corridor. The riparian corridor supports narrow
fringes of Swamp Oak Forest along the lower reaches of the Bellinger River which will be
susceptible to SLR due to coastal squeeze brought on by roads and access tracks. Narrow fringes
of Lowland Rainforest on the Floodplain along the mid reaches of the Kalang River will also be
susceptible to SLR.
6.5.1.7 Groundwater Dependant Ecosystems
Saline intrusion and/or inundation caused by SLR would probably be the most significant impact on
coastal groundwater resources due to climate change, particularly for shallow sandy aquifers along
low-lying coasts (Timms et. al., 2008). SLR can potentially impact groundwater through saline
intrusion and inland migration of the fresh-saline interface and saline inundation and flooding of
unconfined aquifers by seawater (Timms et. al., 2008). Fresh water contaminated by seawater may
render it unsuitable for sustaining GDE’s (Timms et. al., 2008). Increased mean sea-levels could
also change groundwater discharge dynamics.
6.5.1.8 Beaches
Sandy beaches are dynamic environments which undergo continual processes of erosion and
accretion and overall there is a global trend of recession of most sandy beaches. With SLR
beaches are likely to erode and migrate inland. Provided the beaches of the study area can evolve
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naturally there should be a continuum of foreshore sandy habitats in the study area following SLR.
This will be especially significant for species reliant on beach habitats such as nesting marine
turtles and migratory waders. However, where the beach lies in a coastal squeeze between
development and predicted high tides, sandy foreshore habitats will be vulnerable to fragmentation
and loss due to the impacts of SLR. Vulnerable fauna most at risk to these impacts will be turtles
and waders using the supra-littoral habitats. These habitats are likely to be replaced with sea walls
and the surf zone where coastal squeeze is an issue. Management actions such as beach
nourishment will only temporarily ameliorate these impacts.
6.5.1.9 Threatened Species
Appendix D contains a list of threatened species known or potentially occurring in the study area
and surrounds, and their associated habitat types and vulnerability to SLR.
Potential impacts of SLR on flora and fauna species in the study area are generally related to
impacts on habitat quality and extent. Many species known from the study area would not be
considered to specialise in one particular habitat and are relatively adaptable to minor losses or
changes in the areas of available habitat. For example, a shift in community composition between
broad-leaved paperbark and swamp oak may result in fewer nectar reserves available as a food
source for birds and arboreal mammals. Fauna groups using these habitats may be found at a
lesser density should this shift occur. Shifts in the diversity and composition of the groundcover
may also occur (i.e. increase in more salt-tolerant species such as Sporobolus virginicus) which
may have some minor effects on fauna feeding patterns.
Some species are habitat specialists and will be more vulnerable to the impacts of SLR on areas of
essential habitat. The effects of potential losses of freshwater wetlands on acid frogs, beach
erosion effects on turtles and waders, and changes in aquatic biota in mangroves and the potential
flow on effects to waders are described above. In addition, the effects of poor water quality
resulting from SLR into agricultural lands on habitat specialists such as migratory waders and acid
frogs have been discussed.
6.6 Assessment of Risk Similar to the assessment of risk to infrastructure and property (see Section 4), an assessment of
risk has been undertaken for the high value natural assets. Table 6-2 summarises the risk of
inundation and salinity intrusion to EEC’s within subcatchments of the study area under the
immediate, 2050 and 2100 SLR scenarios. Based on the risk assessment the following High Value
Natural Assets are most at risk to SLR within the study area:
• Coastal Saltmarsh (low to high risk);
• Swamp Oak Floodplain Forest (medium risk);
• Freshwater Wetlands on Coastal Floodplains (medium to extreme risk);
• Swamp Sclerophyll Forest on Coastal Floodplains (medium to extreme risk);
• Lowland Rainforest (high risk);
• Lowland Rainforest on Floodplain (medium to extreme risk);
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• Littoral Rainforest (extreme risk); and
• Subtropical Coastal Floodplain Forest (medium to extreme risk).
Recommended mitigation options to address these SLR threats are discussed below.
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Table 6-2 Sea Level Rise Risk Assessment and Mitiga tion Options for High Value Natural Assets
Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
URUNGA
URUNGA Coastal Saltmarsh EEC
Ecological Community High High High Yes
-maintain extent and condition
- restoration and connectivity to potential new habitats
- connectivity to potential new habitats
URUNGA Freshwater Wetland EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- restoration and connectivity to potential new habitats
- connectivity to potential new habitats
URUNGA Littoral Rainforest EEC
Ecological Community
Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
URUNGA Mangrove Ecological Community Medium Medium Medium
URUNGA
Sub-tropical Coastal Floodplain Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- restoration and connectivity to potential new habitats
- connectivity to potential new habitats
URUNGA Swamp Oak Floodplain Forest EEC
Ecological Community Medium Medium Medium
URUNGA Swamp Sclerophyll Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- restoration and connectivity to potential new habitats
- connectivity to potential new habitats
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Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
RALEIGH
RALEIGH Coastal Saltmarsh EEC
Ecological Community
High High High Yes -maintain extent and condition
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
RALEIGH Freshwater Wetland EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
RALEIGH Littoral Rainforest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
RALEIGH
Lowland Rainforest on Floodplain EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
RALEIGH Mangrove Ecological Community Medium Medium Medium
RALEIGH
Sub-tropical Coastal Floodplain Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new
- connectivity to potential new habitats
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Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
habitat
RALEIGH Swamp Sclerophyll Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
MYLESTOM
MYLESTOM Coastal Saltmarsh EEC
Ecological Community
Low Medium Medium
MYLESTOM Littoral Rainforest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
MYLESTOM Mangrove Ecological Community Medium Medium Medium
MYLESTOM
Sub-tropical Coastal Floodplain Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
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Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
MYLESTOM Swamp Sclerophyll Forest EEC
Ecological Community
Not Applicable Medium High Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
REPTON
REPTON Coastal Saltmarsh EEC
Ecological Community High High High Yes
-maintain extent and condition
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
REPTON Freshwater Wetland EEC
Ecological Community
Not Applicable Medium High Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
REPTON
Sub-tropical Coastal Floodplain Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
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Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
REPTON Swamp Sclerophyll Forest EEC
Ecological Community
Not Applicable Medium High Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
BRIERFIELD
BRIERFIELD Freshwater Wetland EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
BRIERFIELD Lowland Rainforest EEC
Ecological Community
Not Applicable High High Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
BRIERFIELD
Lowland Rainforest on Floodplain EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
BRIERFIELD Swamp Sclerophyll Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- connectivity to potential new habitats
- land acquisition to provide buffers and
- connectivity to potential new habitats
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Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
- grazing management
- ASS management
potential new habitat
FERNMOUNT
FERNMOUNT Freshwater Wetland EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
FERNMOUNT
Sub-tropical Coastal Floodplain Forest EEC
Ecological Community Medium High High Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
FERNMOUNT Swamp Sclerophyll Forest EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
VALERY
VALERY Freshwater Wetland EEC
Ecological Community High High High Yes
- maintain extent
- weed management
- water quality
- connectivity to potential new habitats
- land acquisition to provide buffers and
- connectivity to potential new habitats
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Location Asset Name Asset Type Immediate 2050 2100 Treatment Required?
No Regrets Actions
Option 1 (recommended) Option 2
protection
- grazing management
- ASS management
potential new habitat
BELLINGEN
BELLINGEN Freshwater Wetland EEC
Ecological Community Extreme Extreme Extreme Yes
- maintain extent
- weed management
- water quality protection
- grazing management
- ASS management
- connectivity to potential new habitats
- land acquisition to provide buffers and potential new habitat
- connectivity to potential new habitats
BELLINGEN Lowland Rainforest EEC
Ecological Community
Not Applicable
Not Applicable High Yes
- maintain extent
- weed management
- fire management
- connectivity to potential new habitats
- seed banking and propagation
- seed banking and propagation
BELLINGEN
Lowland Rainforest on Floodplain EEC
Ecological Community
Not Applicable
Not Applicable Medium
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7 Summary and Discussion
7.1 SLR and Changed Frequency of Inundation A key impact of SLR on tidal inundation is that the occurrence of significant inundation events will
become more frequent. An example of this is that under 0.9 m of SLR, a king tide event will
produce a peak tidal inundation level that currently only occurs during the 100-year ARI event. This
means that instead of a peak offshore tidal level of 2.6 m AHD occurring on average once every
100 years, under 0.9 m of SLR, it is likely to occur several times a year during king tide conditions
(see Table 7-1). Under just 0.4 m of SLR, a king tide event which currently only occurs on average
only a few times each year (with a peak level of 2.0 m AHD), will create a marginally lower level of
inundation than is currently experienced (on average) once every 20 years.
Table 7-1 Adopted Ocean Levels for Bellinger-Kalang Estuary and Coastline
Design Event 0 m SLR (Current)
+0.4 m SLR
+0.7 m SLR
+0.9 m SLR
+1.4 m SLR
Spring Tide 0.69 (0.70) 1.09 (1.10) 1.39 (1.40) 1.59 (1.60) 2.09 (2.10)
King Tide 1.08 (1.60) 1.48 (2.00) 1.78 (2.30) 1.98 (2.50) 2.48 (3.00)
20-year ARI tide 1.60 (2.20) 2.00 (2.60) 2.30 (2.90) 2.50 (3.10) 3.00 (3.60)
100-year ARI tide 2.10 (2.60) 2.50 (3.00) 2.80 (3.30) 3.00 (3.50) 3.50 (4.00)
Note: values shown in italics adopted for the coastline (Dalhousie Creek and Oyster Creek)
7.2 Tidal Inundation The purpose of the study is to produce a ‘first-pass’ assessment of areas that may be at risk from
tidal inundation due to SLR, which may be used by Council to undertake further studies in order to
evaluate potential risks associated with the design inundation events. In particular, an attempt has
been made to highlight key areas that are susceptible to tidal inundation which will be exacerbated
by rising sea levels.
The areas subject to tidal inundation are based on interpretation of the mapped inundation extents
provided in Appendix B which are provided for the purpose of broad-scale assessment. It should be
noted that changes to inundation are shown as overlays to recent (2009) aerial photography which
should be considered in view of the local topography and the broader inundation extent mapped for
the area.
Inundation extents include the main waterway areas of the Bellinger and Kalang River which are
crossed by several bridges. Further analysis of the peak water level estimated at major bridges
crossing the Bellinger and Kalang Rivers is summarised in Table 7-2. The results show that major
bridge crossings would not be subject to tidal inundation for all design events up to and including a
major storm event (100-year ARI tide) with 1.4 metres of SLR.
Further discussion of changes to tidal inundation extents due to sea level rise for the Bellinger-
Kalang estuary, Dalhousie Creek and Oyster Creek is presented in the following sections.
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Table 7-2 Peak Tide Level at Major Bridge Crossings
Bridge Crossing Deck
Level* (m AHD)
100-year ARI Peak Water level (m AHD) SLR 0.0m
SLR 0.4m
SLR 0.7m
SLR 0.9m
SLR 1.4m
Bowraville Road at Brierfield 10.0 2.1 2.4 2.6 2.8 3.3
Newry Island Drive at Urunga 6.1 2.0 2.3 2.5 2.7 3.2
Pacific Highway at Urunga 9.5 2.0 2.3 2.6 2.8 3.2
Railway at Urunga 8.7 2.0 2.3 2.6 2.8 3.2
Railway at Repton 9.7 2.0 2.4 2.6 2.8 3.2
Old Pacific Highway at Raleigh 6.8 2.0 2.4 2.6 2.8 3.2
Pacific Highway at Raleigh 8.5 2.1 2.4 2.6 2.8 3.2
Bridge Street at Bellingen 4.0 2.3 2.6 2.8 2.9 3.3 * Based on LiDAR and bridge structure data adopted by the WMA 2012 flood model
7.2.1 Bellinger River
The SLR maps of spring tide inundation show that low-lying mangrove and saltmarsh habitat (in
particular around Urunga Lagoon and Urunga Island) will receive regular (weekly) tidal inundation
with 0.4 m of SLR. There are also several other small floodplain areas near Mylestom and
Fernmount where the modelling predicts increased regular tidal inundation with 0.4 m of SLR.
The area of regular (spring tide) inundation increases significantly with a SLR allowance of 0.9 m
and 1.4 m mainly impacting farmland and unsettled areas. However, the 0.9 m and 1.4 m SLR
scenario is estimated to cause regular nuisance inundation of a number of rural properties in the
townships of Mylestom (near Mylestom Drive and Yellow Rock Road), Repton (near Perrys Road
and on the north western side of the Pacific Highway) and Raleigh. Inundation upstream of these
localities is much less significant than the inundation expected downstream.
The existing (0 m SLR) 20-year tidal event (1.6 m AHD) may inundate areas of low-lying floodplain
property around Back Creek and Boggy Creek, and northwest of Repton. Inundation further
upstream the Bellinger River is limited to a few wetland areas between Raleigh and Fernmount. A
SLR of 1.4 m for the 20-year tidal event would drastically increase the inundation experienced in
these areas as well as new areas including: the broad floodplain area between Mylestom and
Raleigh, and to the northwest of Repton and Raleigh; areas to the west of Yellow Rock Road and
to the east of the Pacific Highway; and cleared land between Repton and Mylestom.
The existing (0 m SLR) 100 year tidal event (2.1 m AHD) is predicted to inundate to a level similar
to the 20-year tidal event with a SLR of 0.4 m. Again sections of rural property within the floodplain
may be inundated. SLR may exacerbate this less frequent inundation resulting in events that
inundate the vast majority of the Bellinger River floodplain around the townships of Raleigh,
Mylestom, Repton, Fernmount and Bellingen. With SLR of 1.4 m, high or extreme risk is calculated
for the following:
• At Raleigh, several rural, residential and primary production properties; the Raleigh Waste
Management Centre, and sewer / stormwater services. Other assets including numerous minor
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roads, part of the North Coast Railway and Pacific Highway and heritage building items (i.e. a
farmhouse). Natural assets include EEC’s of coastal saltmarsh, freshwater wetland, littoral
rainforest, lowland rainforest, subtropical coastal floodplain forest and swamp sclerophyll forest;
• At Mylestom, minor local roads including George Street, Mylestom Drive, River Street and an
unnamed road. Natural assets include EEC’s littoral rainforest, subtropical coastal floodplain
forest and swamp sclerophyll forest;
• At Repton, residential property off Mylestom Drive and rural property at Baily Street, Mylestom
Drive and Perrys Road; minor roads including Keevers Drive, Mylestom Drive and River Street;
and a heritage listed Ruined Timber Mill. Natural assets include EEC’s of coastal saltmarsh,
freshwater wetland, subtropical coastal floodplain forest and swamp sclerophyll forest;
• At Fernmount, rural property off Waterfall Way; primary production land off Nicolson Street and
Waterfall Way; a major road (i.e. Waterfall Way) and minor roads including Baker Street,
Nicholson Street and an unnamed road. Natural assets include EEC’s of freshwater wetland,
subtropical coastal floodplain forest and swamp sclerophyll forest; and
• At Bellingen, rural properties off North Bank Road, Slarkes Road and Wheatley Street; primary
production land off Cahill Street, North Bank Road, Waterfall Way and Wheatley Street; minor
local roads including Bridge Street, Doepel Street, John Glyde Road, North Bank Road and
Slarkes Road; and low-lying sewer and stormwater services (i.e. rising main and drainage main)
near those localities. Natural assets include EEC’s of freshwater wetland, and lowland
rainforest.
7.2.2 Kalang River
The SLR maps of spring tide inundation show only marginal increase to inundation experienced
along the Kalang River with 0.4 m of SLR. The most notable change would be the connection
between Boggy Creek and Back Creek which only occurs at present under king tide conditions.
The area of regular (spring tide) inundation increases significantly with a SLR allowance of 0.9 m
and 1.4 m regularly inundating large parts of the Urunga Golf course and adjacent riverfront
properties as well as rural properties located on Newry Island. With projected SLR increases of this
magnitude, regular tidal inundation may be experienced by creeks (e.g. Picket Hill Creek) and low-
lying wetlands fringing the Kalang River between Tarkeeth and Newry Island. Regular inundation
extents upstream of Tarkeeth are much less significant than downstream localities and isolated to
those small tributaries joining the river.
More infrequent events (i.e. king tides) with 1.4 m of SLR may also affect similar low-lying areas,
albeit with marginally greater tidal excursion than that predicted for the spring tide scenario. A few
low-lying industrial precinct properties off Marina Crescent, riverside residential properties on
Newry Island and off Crescent Close, and low-lying residential properties along Mogo Street
overlooking Urunga Lagoon may also be affected. Tidal excursion may also increase to the wetland
to the south of Hillside Drive, affecting the rear of some properties located at its westernmost
extent.
The existing (0 m SLR) 20-year tidal event may inundate part of the Urunga Golf Course and
nearby private properties to a similar level as a spring tide event with a SLR of 0.9 m. For this
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scenario, inundation further upstream the Kalang River is limited to fringing wetlands between
Tarkeeth and Newry Island. A SLR of 1.4 m would exacerbate the inundation experienced in these
areas as well as the low-lying properties noted above.
As noted above, the existing (0 m SLR) 100 year tidal event is predicted to inundate to a level
similar to the 20-year tidal event with a SLR of 0.4 m. Under this rare scenario, rural property within
the floodplain may be inundated as well as low-lying properties adjacent to the Kalang River and
Urunga Lagoon. SLR of 0.9 m and 1.4 m may exacerbate inundation further resulting in events
affecting a majority of the narrow floodplain between Tarkeeth and Urunga. With a SLR of 1.4 m,
numerous properties situated on Newry Island and at Urunga in the vicinity of the golf course /
tennis courts and lagoon would be affected. For this scenario, high and extreme risk is calculated
for the following:
• At Urunga, numerous residential properties, some rural and primary production properties at the
following locations (i.e. Burrawong Parade, Crescent Close, Hollis Close, Island Place, Marina
Crescent, Marshall Place, Melaleuca Place, Morgo Street, Newry Island Drive, Old Punt Road,
Pacific Highway, Riverside Drive, Short Cut Road, South Arm Road, The Grove, Vernon
Crescent and Yellow Rock Road); and associated sewer services (i.e. gravity main, pressure
main, pumping main, rising main, transfer main) and stormwater services (i.e. drainage mains)
in the area. Community assets include the Urunga Head Holiday Park and cultural planting and
Urunga Scouts – Bellinger Head State Park. Natural assets include EEC’s of coastal saltmarsh,
freshwater wetland, littoral rainforest, subtropical coastal floodplain forest and swamp
sclerophyll forest; and
• At Brierfield, several rural properties / primary production land and minor roads including
Bowraville Road, Martells Road, South Arm Road and Hains Lane. Natural assets include
EEC’s of freshwater wetland, lowland rainforest and swamp sclerophyll forest.
7.2.3 Dalhousie Creek and Oyster Creek
At present, both Dalhousie Creek and Oyster Creek currently experience only minor tidal
inundation during spring and king tides. Increased inundation extents predicted due to SLR is
highly localised and controlled by the steep topography surrounding the ICOLLs. No private
properties are expected to be affected by the predicted increased inundation during infrequent tidal
inundation events (i.e. 20-year and 100-year ARI) even with 1.4 metre of SLR.
7.3 Limitations of Inundation Mapping and Modelling There are a number of limitations to the current study which influence how the results should be
interpreted. These limitations are summarised in the points below:
• The inundation extents estimated for Dalhousie Creek and Oyster Creek are derived from the
simple ‘bath tub’ approach which assumes that a constant water level across the entire
waterway provides a suitable calculation of oceanic inundation for small coastal waterbodies
such as those present in the study area;
• Models have not been calibrated to storm surge events (only flood or typical tidal conditions).
While the existing calibrations provide reasonable confidence in the model predictions,
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additional calibration to actual significant tidal inundation events would further increase
confidence in model predictions;
• Likewise, the estuary model is not calibrated for hydrodynamics (water level and flow) or
advection/dispersion (salinity) and as such the focus should be on the relative changes to
inundation depth and salinity between the different SLR scenarios rather than the absolute
values predicted by the model;
• The study does not consider river flooding and tidal storm surges occurring at the same time,
and the construction of future defences which may be built to reduce the impact of SLR;
• There is some uncertainty surrounding the design wave setup conditions at trained river
entrances. A conservative approach has been adopted for the study in light of DECCW (2010)
guidelines and published work relating to wave setup for various entrance conditions;
• Coastal inundation lines do not consider wave run-up, overtopping or coastal erosion; and
• While the inundation model does not include underground sewer or stormwater pipes which
may convey tidal waters behind flood defences, the use of extrapolated water levels in the
mapping process extends inundation into low lying lands beyond flood defences. Higher
resolution 1D-2D modelling incorporating all underground pipe networks could be used to better
assess the risk due to this form of flood risk.
The results of this study should be interpreted as a ‘first pass’ assessment that may be used to
gauge the magnitude of the SLR issue in the estuary. Further refinement will be required to
develop a more detailed understanding of SLR inundation, which may also consider further
modelling assessment(s) to quantify the mitigative performance of potential management options.
7.4 Suggested Provisions for Reviewing and Updating SLR Benchmarks The NSW Floodplain Development Manual suggests that floodplain management plans are
reviewed approximately every five (5) years. While this SLR mapping study does not sit directly
under provisions outlined in the manual, it is recommended that revised estimates of tidal
inundation under SLR scenarios be re-assessed every five to ten years or when significant new
information or guidelines become available.
New information or guidelines which would influence when an update or review of the SLR
inundation maps should occur include:
• Changes to NSW Government Flood Policy;
• Updates to IPCC estimates of SLR (the IPCC Fourth Assessment Report (AR4) was completed
in early 2007. The IPCC is currently starting to outline its Fifth Assessment Report (AR5) which
will be finalized in 2014);
• Actual local observations of SLR;
• New LiDAR data becomes available; or
• Significant changes to the hydraulics of the estuaries.
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7.4.1 Independence of Mapping from Changes to Projected Rates of SLR
Updates to benchmarks will not influence the mapped outputs produced in the study which provide
an indication of tidal inundation for 0.0, 0.4, 0.9 and 1.4 metres of SLR. The majority of uncertainty
regarding SLR estimates is to do with the projected rate of sea level rise. So while the current
benchmarks assume that 0.4 m of SLR will occur by 2050, the maps indicate what 0.4 m of SLR
looks like and not when this will occur. If the rate of sea level rise is slower than currently
calculated, then 0.4 m of SLR may not occur to say 2100. However, if the rate of SLR is quicker
than currently calculated, it may occur closer to 2040 for example.
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7.5 Sea Level Rise Mitigation Options
7.5.1 Estuary Inundation
Key management options that are recommended to Council for managing estuary inundation hazard broadly are outlined in Table 7-3. The options have
been collated based on the multi criteria analysis conducted in the CZMS, then refined to suit the needs of the assets types in the context of Bellingen
Shire. Detailed descriptions of all options are provided in Appendix E of the Bellingen CZMS (2014).
Table 7-3 Recommended Options for Managing Estuary Inundation Hazard
Option: Monitoring
Detail Asset Managed
Monitoring: to collect better information regarding coastal processes and to determine when a risk is approaching. A trigger may be in relation to flood level or flood frequency. The trigger must allow sufficient time for the preferred management option to be funded, approved an implemented. Key monitoring activities would include: • Monitoring of water level / frequency and depth of inundation events for key assets (refer to risk register in
Appendix C) for high/extreme risk assets.
• Monitor distribution and health of estuary ecology, by undertaking regular mapping of coastal habitats (ever 2-5 years), with more regular targeted monitoring activities occurring (e.g. mangrove landward expansion) occurring (e.g. yearly) when a local change in distribution / health of a high value community is identified.
No Regrets Option
All assets with a focus on those at high / extreme risks
Option: Asset Management Planning
Detail Asset Managed
Asset Management Planning: incorporate the likelihood of the coastal hazards to impact upon Council’s assets (e.g. buildings, roads, services etc). The likelihood of a hazard impact and expected timeframe should be incorporated / considered by Council’s asset managers when calculating the time for and cost of replacing an asset. The asset management plan should also incorporate the appropriate action to manage the hazard (refer Audit of Existing Council Assets option below), such as relocating an asset, redesigning an asset, or otherwise using different materials/construction to ensure the replacement asset withstands the hazard over its expected life, avoiding future costs to Council. That is, the approach aims to avoid replacing “like for like” when an asset is in a hazardous location. For non-council assets (e.g. railway, RTA roads), the hazards information should be provided to the asset owner, to inform of the likely risk and enable the asset owner to develop an appropriate hazard management response. Council should encourage continued contact with such asset owners to ensure that their management responses do not negatively impact or contradict the approach and actions of Council to managing coastal hazards.
No Regrets Option
Council’s assets, non-council assets (railway, RTA roads etc)
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Option: Audit of Existing Council Built Assets
Detail Asset Managed
Audit of Existing Council Assets: to support the management of coastal hazards when assets are replaced. The audit should initially focus upon those assets at extreme or high risk over the immediate timeframe, and then extend to high / extreme risks at future timeframes and so on. The audit should determine, for each asset at risk, which of the following actions is most suitable: • Relocation, to move the replacement asset beyond the area of likely hazard over its lifespan; • Redesign of the replacement asset, to withstand hazard impacts (e.g. floor levels for buildings, salt resistant
materials and / or tidal flaps for stormwater outlets, as so on); or • Manage to fail, where it is suitable to remove instead of replace an asset at the end of its life. • As an interim option, life extension activities (including repairs following damage) may also be considered, until
such time as the preferred action (relocate or redesign) can be afforded. There may need to be further investigation of redesign options for existing assets, for example, investigating salt resistant piping for stormwater, or tidal flaps to reduce inundation, and so on. This option effectively selects the appropriate option from relocation, redesign/retrofit or otherwise for individual assets, accounting for coastal hazards in combination with the other priorities for Council. Refer to Appendix E in the CZMS (BMT WBM, 2014) for further details on ‘relocation’, ‘retrofit/redesign’ and ‘manage to fail’ options.
No Regrets Option
All assets with a focus on those at high / extreme risks for immediate, then future timeframes. Assets at lower risk can then be assessed if resources permit
Option: Use of Existing Flood Policy
Detail Asset Managed
Use of the existing Flood Policy: is likely to be suitable as an interim measure to regulate estuary inundation risks due to periodic ocean events for future development and redevelopment of existing properties. Interim use of the policy should only be done until the next amendment of Councils Floodplain Risk Management Plan (to incorporate the outcomes of the most recent flood modelling study undertaken in 2012 for the Lower Floodplain). Revision of the Floodplain Risk Management Plan should then be considered as the peak strategy for regulation of all possible inundation in the study area. The linkages between fluvial inundation, coastal inundation and estuary inundation can be clearly documented in that Plan and the most appropriate policy response specified.
No Regrets Option
Redevelopment of existing assets or new developments
Option: Community Education
Detail Asset Managed
Community Education: is aimed at ongoing updates to community regarding occurrence of climate change, particularly sea level rise, and must include an outline of the actions being undertaken by Council and others to manage and mitigate risks. The aim of education is to build resilience of the community to managing coastal hazards, when they manifest.
No Regrets Option
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Option: LEP Review and Rezoning
Detail Asset Managed
LEP Review and Rezoning: to ensure that land is not developed inappropriately. That is, land that is known to be at risks from coastal hazards, particularly where such land is currently vacant, should be rezoned (or existing zoning retained) to Environmental Management, Environmental Conservation, Public Recreation or similar. This options is appropriate for areas identified with a high or extreme risk from periodic storm driven estuary inundation (as identified in this risk assessment), as well as areas likely to be impacted by permanent estuary inundation due to sea level rise (as modelled in this study, but not addressed in this risk assessment). Rezoning / zoning of vacant land to ensure the land is not considered for development at any stage in the future. As the principal development guide for day to day assessments of developments, this option would also include updates to the DCP 2010 with specific regard to the recommendations of this study.
No Regrets Option
Areas of undeveloped land: • at high / extreme risk of storm driven –
estuary inundation
• likely to be impacted by permanent estuary inundation due to sea level rise
Option: Habitat Management
Detail Asset Managed
Habitat Management: should focus on high values ecological communities identified with high/extreme risks, to ensure that the health and resilience of these communities is reattained as best as possible under the increasing pressures of sea level rise. This option includes maintaining the extent and condition of the high values ecological communities at risk through the undertaking the following No Regrets actions:
• monitoring; • weed management; • water quality protection; • fire management; • grazing management; and • acid sulphate soil management. Furthermore, future management options to improve the resilience of the high value communities to sea level rise include: • restoration and connectivity to potential new habitats
• land acquisition to provide buffers and potential new habitat; and • seed banking and propagation.
Details of where to apply these specific actions/options are noted in Table 6-2, and discussed below.
No Regrets Option
Future management actions
High value ecological communities at risk of estuary inundation
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7.5.2 High Value Natural Assets
High Value Natural Assets in the riparian corridor, floodplain and estuarine reaches of the Bellinger
and Kalang River estuaries are most at risk from SLR. Given their limited distribution in a largely
cleared agricultural setting, and the poor condition of the riparian vegetation, these communities
may require management intervention to improve their resilience to SLR and in the case of tidal
wetlands, assist with habitat transition. Shoo et al. (2012) modelled SLR impacts on coastal
wetlands in south-east Queensland and found that the seaward margin of wetlands are
predominantly on public land but would be lost due to SLR, whereas wetlands are potentially
gained on the landward side of SLR, but predominantly occur on private land. A similar scenario is
expected in the study area.
It is recommended that Council initially focus actions to address SLR within the extreme to high risk
locations and riparian reaches. Given the timeframes over which projected SLR impacts may occur
(2050 onwards), and the complicated interactions involved, Council will be required to develop
ongoing adaptive strategies (including action on Table 6-2 and Table 7-3) to assess and manage
SLR impacts. This will require regular monitoring to map the distribution and condition of coastal
habitats in association with SLR (see Section 7.6 for more detail).
7.5.2.1 Tidal/Near-Tidal Wetlands
Mangroves are expected to be able to colonise new habitat at a rate that keeps pace with most
SLR predictions, subject to the slope of adjacent land, the actual rate of SLR and the presence of
obstacles to landward migration of the landward boundary of the mangrove (e.g. seawalls and
other shoreline protection structures). Under SLR, it is anticipated that mangrove communities may
transition into locations previously occupied by Coastal Saltmarsh and floodplain wetlands and may
migrate further upstream with the tidal front. It is recommended that regular monitoring is carried
out to map mangrove distribution in association with SLR to identify sites of mangrove retreat and
invasion of more vulnerable communities, notably Coastal Saltmarsh. Recommended monitoring
sites within the study area are discussed in Section 7.6.
Swamp Oak Forest and Coastal Saltmarsh within the mid to lower reaches of the estuaries may be
affected by increased inundation and saline intrusion and potential changes to groundwater as a
result of SLR. SLR management actions proposed for these habitats should also focus on
conserving adjacent buffers for future natural migration in response to SLR, increasing
rehabilitation efforts through planting and weed management and improving connectivity between
habitats (i.e. restoration). These actions may assist natural transition as a result of SLR and may
help ensure that threatened wetland habitat is conserved for a range of dependant species, such
as migratory waders.
7.5.2.2 Riparian Corridor
It is recommended that actions aimed at managing SLR within all reaches focus on conserving
buffers adjacent to riparian corridors and maintaining rehabilitation efforts. This is particularly
important in the lower reaches of the Bellinger and Kalang Rivers which are most susceptible to
SLR and support Endangered Swamp Oak Forest and Coastal Saltmarsh riparian communities.
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It is recommended that the width of the riparian corridor be increased through planting and
restoration and overall condition improved through weed management. The riparian rehabilitation
recommendations and priority sites outlined in the Bellinger Estuary Action Plan Reach Plan
(Bellingen Shire Council, 2011) and the Bellinger and Kalang Rivers Estuary Action Plan Stage 2
(Bellingen Shire Council, 2014) should be maintained and adapted in response to SLR. These
actions may improve the resilience of the riparian corridor to erosion whilst maintaining the
important functions of riparian vegetation, such as water quality control, and ensuring riparian
habitat is conserved for threatened species such as Koala.
7.5.2.3 Floodplain Habitats
Freshwater Wetlands and Swamp Sclerophyll Forest on the floodplains in the study area may be
affected by increased inundation, saline intrusion, mangrove invasion (particularly in Freshwater
Wetlands) and potential changes to groundwater level and quality as a result of SLR. SLR actions
proposed for these habitats should focus on conserving buffers adjacent to these wetlands for
future natural migration in response to SLR, increasing rehabilitation efforts through planting, weed
management, water quality protection, grazing management and ASS management and improving
connectivity between these communities (i.e. restoration). These actions may assist natural
transition as a result of SLR whilst maintaining the important functions of floodplain wetlands, such
as water quality control, and may help ensure that threatened wetland habitat is conserved for a
range of dependant species such as Litorea aurea (Green and Golden Bell Frog), Phaius australis
(Southern Swamp Orchid), Pteropus poliocephalus (Grey-headed Flying-fox), Litoria olongburensis
(Wallum Sedge Frog) and Crinia tinnula (Wallum Frog).
SLR actions proposed for Lowland Rainforest and Subtropical Coastal Forests on the floodplains
should focus on conserving buffers for future migration in response to SLR, increasing
rehabilitation efforts through planting and weed management and maintaining firebreaks. In
addition, given their small and isolated extent it is recommended that Lowland Rainforest species
be preserved through seed banking and propagation. These actions may assist natural transition
as a result of SLR and would help ensure these communities and associated species are
conserved.
7.5.2.4 Littoral Rainforest
SLR actions proposed for these groundwater-dependant ecosystems should focus on increasing
rehabilitation efforts to improve condition through planting and weed management and maintaining
firebreaks. In addition, given their small and isolated extent it is recommended that rainforest
species be preserved through seed banking and propagation. These actions may help ensure
these communities and associated species are conserved. Any habitat transition in these
communities will be very slow due to inherently low levels of recruitment and will be dependent on
changes in groundwater quality and depth and availability of habitat conditions free from fire and
other threatening processes, such as weed invasion and adjacent landuses.
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7.6 Proposed Monitoring Sites Based on the available data and a ground truthing exercise, eight sites were identified for ongoing
monitoring of geomorphic response and ecological community change. Site selection was based
on presence of High Value Natural Assets predicted to be impacted by SLR and easy accessibility.
Table 7-4 provides a summary of the recommended monitoring sites shown in Figure 6-1.
Table 7-4 Habitat Response to SLR Monitoring Sites
Site Number
MGA Zone 56 (GDA94) Location High Value Natural Assets at
Risk to SLR Easting Northing
1 500939 6626971
Directly west of Pacific Highway and south of Marina Crescent
mangroves / mudflats
saltmarsh
SEPP14
2 501711 6627266 East of Yellow Rock Road mangroves / mudflats
saltmarsh
3 502450 6628480
South of Yellow Rock Road mangroves / mudflats
saltmarsh
SEPP14
4 500496 6625604 Adjacent to Melaleuca Place mangroves
saltmarsh
5 502400 6624232
South-eastern corner of Urunga Lagoon, approx. 400m north of Hungry Head Road
mangroves
saltmarsh
SEPP14
SEPP26
6 502690 6625470 North eastern corner of Urunga Lagoon
mangroves / mudflats
saltmarsh / salt flats
7 502700 6628820 North of site 2 floodplain wetland
8 502230 6625970 North-western corner of Urunga Lagoon
disturbed, cleared, reclaimed, mudflats
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8 Conclusions
8.1 Estuary Inundation Climate change and sea level rise have the ability to impact private and public land and assets
within the Bellingen LGA. This SLR mapping investigation was undertaken to identify areas with the
LGA that are likely to be impacted (negatively or otherwise) by SLR. The study has updated and
made use of existing (and newly developed) computer models to calculate tidal inundation in the
main river estuary and ICOLL’s located in the LGA. The study has determined the estuarine and
coastal inundation extents for a range of design ocean events and four epochs and associated
mean sea levels (MSL).
Based on the estuary inundation modelling, key areas within the Bellinger-Kalang Estuary that may
be impacted by more frequent tidal inundation (exacerbated by SLR) include:
• farmland and unsettled low-lying floodplain areas around Mylestom and Fernmount;
• a number of rural properties in the townships of Mylestom (near Mylestom Drive and Yellow
Rock Road), Repton (near Perrys Road and on the north western side of the Pacific Highway)
and Raleigh; and
• part of the Urunga Golf course and adjacent riverfront properties as well as some rural
properties located on Newry Island.
Areas that are currently not impacted by tidal inundation but may begin to experience infrequent
(i.e. 20-year and 100-year ARI events) with SLR include:
• the broad floodplain area between Mylestom and Raleigh, and to the northwest of Repton and
Raleigh;
• low-lying areas to the west of Yellow Rock Road and to the east of the Pacific Highway;
• low-lying land cleared between Repton and Mylestom;
• several rural, residential and primary production properties around the townships of Raleigh,
Mylestom, Repton and Fernmount;
• numerous rural, residential properties situated on Newry Island and waterfront properties along
the Kalang River at Urunga;
• properties at the Urunga Industrial precinct; and
• the Urunga Golf Course / tennis courts and waterfront properties in the immediate vicinity
lagoon and Urunga Lagoon.
These areas include a large area of mapped Regionally Significant Farmland (RSF). The impacts
of increased tidal inundation on soil profiles in RSF were not specifically considered in this study
however this could be investigated further in future using the mapping data derived from this study.
Due to the steep topography surrounding Dalhousie Creek and Oyster Creek ICOLLs, inundation
extents are largely confined to the main waterway and adjacent low-lying intertidal area. Private
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properties and other infrastructure are not expected to experience any significant inundation during
infrequent tidal inundation events (i.e. 20-year and 100-year ARI) even with 1.4 metre of SLR.
8.2 Ecological Impacts The study area supports a range of High Value Natural Assets at risk from SLR. Based on SLR
projections, it is anticipated there may be increased inundation and saline intrusion into Coastal
Saltmarsh and Swamp Oak Forest communities in the lower and middle estuarine reaches. This
may result in landward retreat of these communities if habitat conditions are suitable and
expansion of mangroves landward and further upstream with the tidal front. Potential inundation of
floodplain wetland habitats is also anticipated for all estuary reaches.
Provided conditions are suitable for colonisation, estuarine wetland habitats are expected to
migrate landwards in response to a shift in the tidal planes. Some habitats, particularly Coastal
Saltmarsh, are prone to coastal squeeze which may prevent landward migration as sea levels rise.
This is particularly evident in the lower reaches of the Kalang River where existing Coastal
Saltmarsh communities abut residential development including roads.
Due to natural migration, low-lying, flat areas above the tidal range, particularly those that lie
adjacent to existing vulnerable habitats, may become increasingly important to protect and restore
as potential areas for future habitat migration. This includes agricultural lands which have been
previously cleared. Priority areas for protection should also be located along tributaries and creeks.
It is therefore recommended that Council considers management measures that provide buffering,
connectivity and migration of vulnerable habitats, particularly Freshwater Wetlands, Coastal
Saltmarsh, Swamp Oak Forest, Swamp Sclerophyll Forest, Lowland Rainforest and riparian
vegetation.
Various actions could be implemented by Council to protect vulnerable habitats from SLR as
follows:
• protecting land adjacent to vulnerable habitats (listed above) from development so they have
land to migrate to;
• reducing non-SLR threats such as weeds and disturbance-dependent species (such as
Phragmites) to increase habitat condition and therefore resilience; and
• remediation of lands such as low-productivity pastures through hydrological works (e.g.
introducing more natural flow regimes to assist habitat migration by either improving the function
of (or removing) artificial controls such as culverts and levees and plantings to assist habitat
establishment).
Shoo et al., 2012 identified several mechanisms which could be implemented by Council to protect
vulnerable habitats from SLR. Whilst Council may not be able to achieve many of these objectives
due to budget and planning constraints, they should be considered at the strategic level to help
reduce impacts on vulnerable habitats and to enable Council to respond if priorities and funding
change in the future:
• more stringent land-use laws, buffer controls and incentives for privately-held land protection for
habitat migration. For example, Council could educate and provide grants to encourage
Bellingen Shire Estuary Inundation Mapping 130 Conclusions
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landholders to preserve land for habitat migration adjacent to vulnerable habitats so susceptible
habitats have somewhere to migrate to; and other opportunities could be considered e.g. OEH
Conservation Agreements;
• preventing the construction of hard structures, such as walls and roads, adjacent to existing
vulnerable habitats which may prevent their landward migration (note: as land owners are
permitted to construct tracks on private land without consent from Council, educational
strategies may be the most effective way to address this matter);
• ongoing mapping (every 5 years in first instance then every 1 to 2 years when impacts are being
realised) to identify habitats most vulnerable to SLR and any habitat migration response that
might have occurred;
• modelling of landscape change to predict habitat change with SLR;
• assessing the adequacy of the local reserve system for maintaining vulnerable habitat
ecosystem services and functions;
• identifying priority sites for land acquisition to ensure all vulnerable habitats are protected and
which allow habitat migration; and
• increasing acquisition of vulnerable habitats and adjacent land for inclusion in the reserve
system.
Note: in relation to land-use laws and buffer controls, in many instances Bellingen Shire is fortunate
as it is likely that areas adjoining existing ecologically significant and threatened habitats are
already mapped as flood prone land and possess rural zonings that, in combination, restrict the
likelihood of development occurring that would provide an obstacle to the landward migration of at
risk communities.
Bellingen Shire Estuary Inundation Mapping 131 References
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Delgado, P., Kelley, P., Murray, N. & Satheesh, A., 2012. Source User Guide, eWater Cooperative
Research Centre, Canberra, Australia.
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Pass National Assessment. Commonwealth of Australia
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Area, Report prepared for Bellingen Shire Council, July 2006.
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American Samoa mangroves. Wetlands Ecology and Management, 15, 391-404.
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soils by tidal inundation: Effectiveness and geochemical implications. NSW Coastal Conference
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groundwater dependent ecosystems, Volume 3 – Identification of high probability groundwater
dependent ecosystems on the coastal plains of NSW and their ecological value, NSW Department
of Primary Industries, Office of Water, Sydney
Lawson and Treloar (2003), Bellinger and Kalang Rivers Estuary Processes Study, Report
prepared for Bellingen Shire Council, August 2003.
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R. Rhodes and Kerrie A. Wilson. Managing for change: wetland transitions under sea-level rise
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River and Wetlands Unit, NSW Department of Environment Climate Change and Water.
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Tanaka and Tinh (2008), Wave Setup and River Mouths in Japan, Journal of Water Resources and
Environmental Engineering, N0. 23, November 2008.
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Prepared for Bellingen Shire Council.
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coastlines - potential impacts of climate change. Coast To Coast Crossing Boundaries Conference,
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and Maritime Services, May 2012.
Bellingen Shire Estuary Inundation Mapping A-1 Description of Wave Setup
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Appendix A Description of Wave Setup
In addition to wind, waves can also affect the mean nearshore water levels during storms in a
process called wave setup (see Figure A-1). This occurs as a result of the transfer of momentum
from waves to the water column (see Figure A-2). Wave setup increases as the water depth
decreases and wave dissipation (or breaking) increases (FEMA, 2005).
Consider waves approaching the shoreline (see Figure A-3). Outside of the breaker zone, a
relatively small reduction in mean water level, termed a setdown, will occur. This setdown is small,
approximately 5% of the breaking wave height. However, as the waves break, they transfer
momentum to the water column, causing wave ‘setup’ than can be in the order of 10 to 20% of the
breaking wave height (FEMA, 2005). Wave setup at a river entrance (see Figure A-4) is typically
less than on the open coast due to increased water depth and reduced wave breaking (as
discussed in Section 3.1.3).
Figure A-1 Illustration of Wave Setup (FEMA, 2005)
Bellingen Shire Estuary Inundation Mapping A-2 Description of Wave Setup
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Figure A-2 Wave Setup Due to Transfer of Momentum ( FEMA, 2007)
Figure A-3 Wave Setup and Setdown at a Beach (FEMA, 2005)
Bellingen Shire Estuary Inundation Mapping A-3 Description of Wave Setup
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Figure A-4 Wave Setup at a River Entrance (FEMA, 20 05)
References
Federal Emergency Management Agency (FEMA) (2005). Wave Setup - Coastal Flood Hazard
Analysis and Mapping Guidelines, Focused Study Report, February 2005. Washington D.C.
Accessed 04/10/2013, URL: http://www.fema.gov/media-library-data/20130726-1541-20490-
1234/frm_p1wave1.pdf.
Federal Emergency Management Agency (FEMA) (2007). Guidelines and Specification for Flood
Hazard Mapping Partners, February 2007. Accessed 04/10/2013, URL:
http://www.fema.gov/media-library-data/20130726-1558-20490-5529/frm_cfhamagd26.pdf.
Bellingen Shire Estuary Inundation Mapping B-1 Mapping Compendium of Estuary Inundation
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Appendix B Mapping Compendium of Estuary Inundation
This mapping compendium contains 40 maps each with a unique map name such as ‘event’-‘map
ID’. A list and description of each map ID is presented in Table B-1, while the location of each map
is presented in the index map on the following page.
Each map is of a given design event (100-year ARI, 20-year ARI, king tide or spring tide) and
shows changes to inundation at 0.0 (current), +0.4 m, +0.9 m and +1.4 m sea level rise increments.
Low-lying areas that are potentially vulnerable to flooding from a combination of sea level rise and
a very high tide are shown.
Table B-1 Description of Maps in each Series of the Mapping Compendium
Map ID Description
BK_1 Bellinger-Kalang Estuary – full extent
BK_2 Bellinger-Kalang – Urunga zoom
BK_3 Bellinger-Kalang – Mylestom zoom
BK_4 Bellinger-Kalang – Raleigh zoom
BR_1 Bellinger River – upstream zoom
BR_2 Bellinger River – downstream zoom
KR_1 Kalang River – upstream zoom
KR_2 Kalang River – downstream zoom
Dal Dalhousie Creek – full extent*
Oys Oyster Creek – full extent*
* inundation of Oyster Creek and Dalhousie Creek is based on a simplified ‘bath tub’ mapping procedure.
Table B-2 Description of Design Event Map Colours
Design Event Map Series Colour
Spring tide light to dark pink
King tide yellow, orange, brown
20-year ARI tide light to dark blue
100-year ARI tide light to dark purple
Bellingen Shire Estuary Inundation Mapping C-2 Asset Risk Register
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Appendix C Asset Risk Register
Location Asset Name Asset Type 2010 2050 2100 Treatment Req'd
URUNGA Town Centre, Residential and Rural Property
Residential - Acacia Dr Residential Property Medium Medium Medium
Residential - Allison Pl Residential Property #N/A #N/A Low
Residential - Bellingen St Residential Property Medium Medium Medium
Residential - Burrawong Pd Residential Property High High High Yes
Residential - Christine Cl Residential Property Medium Medium Medium
Residential - Clybucca St Residential Property Low Medium Medium
Residential - Comlaroi St Residential Property Low Medium Medium
Residential - Coopers Ln Residential Property Low Medium Medium
Residential - Crescent Cl Residential Property High High High Yes
Residential - Crescent St Residential Property High High High Yes
Residential - Dolphin Crt Residential Property #N/A Medium Medium
Residential - Elizabeth Dr Residential Property #N/A #N/A Medium
Residential - Hillside Dr Residential Property Low Medium Medium
Residential - Hollis Cl Residential Property High High High Yes
Residential - Island Pl Residential Property High High High Yes
Residential - Jean Cl Residential Property #N/A Low Medium
Residential - Karen St Residential Property Medium Medium Medium
Residential - Kylie St Residential Property Medium Medium Medium
Residential - Lake Crt Residential Property #N/A #N/A Medium
Residential - Marina Cr Residential Property High High High Yes
Residential - Marshall Pl Residential Property High High High Yes
Residential - Melaleuca Pl Residential Property High High High Yes
Residential - Morgo St Residential Property High High High Yes
Residential - Mountview Cr Residential Property #N/A Low Medium
Residential - Newry Island Dr Residential Property High High High Yes
Residential - Odalberree Dr Residential Property #N/A Low Medium
Residential - Old Punt Rd Residential Property High High High Yes
Residential - Pacific Hwy Residential Property High High High Yes
Residential - Panorama Pd Residential Property #N/A #N/A Low
Residential - Raleigh St Residential Property Medium Medium Medium
Residential - River St Residential Property #N/A Medium Medium
Residential - Riverside Dr Residential Property High High High Yes
Residential - Rosedale Dr Residential Property #N/A Low Medium
Residential - Short Cut Rd Residential Property High High High Yes
Residential - South Arm Rd Residential Property Medium Medium Medium
Residential - The Grove Residential Property High High High Yes
Residential - Vernon Cr Residential Property High High High Yes
Residential - Vernon Pl Residential Property High High High Yes
Residential - Wollumbin Dr Residential Property #N/A #N/A Low
Residential - Yellow Rock Rd Residential Property Medium Medium Medium
Rural - Newry Island Drive Rural Property High High High Yes
Rural - Old Punt Rd Rural Property High High High Yes
Rural - Pacific Hwy Rural Property High High High Yes
Rural - Short Cut Rd Rural Property High High High Yes
Rural - South Arm Rd Rural Property High High High Yes
Rural - Yellow Rock Rd Rural Property High High High Yes
Primary Production, Forestry and Industry
Forestry Land Forestry Zone Medium Medium Medium
General Industrial Land General Industrial Zone High High High Yes
Infrastructure Land Infrastructure Zoned Land Low Low Low
Primary Production - Martells Rd Primary Production High High High Yes
Primary Production - Newry Island Drive Primary Production High High High Yes
Primary Production - Old Punt Rd Primary Production High High High Yes
Primary Production - Pacific Hwy Primary Production High High High Yes
Primary Production - Short Cut Rd Primary Production High High High Yes
Primary Production - South Arm Rd Primary Production High High High Yes
Primary Production - Yellow Rock Rd Primary Production High High High Yes
Transport Infrastructure
Pacific Hwy Major Road Extreme Extreme Extreme Yes
Allison Place Minor Road #N/A Low Medium
Atherton Drive Minor Road High High High Yes
Bellingen St Minor Road High High High Yes
Bonville St Minor Road Low #N/A #N/A
Burrawong Pde Minor Road #N/A #N/A Low
Cemetery Rd Minor Road #N/A #N/A Low
Cemetery Road Minor Road #N/A #N/A Low
Christine Cl Minor Road #N/A #N/A Low
Clybucca St Minor Road Medium Medium Medium
Comlaroi St Minor Road Low Medium Medium
Coopers Lane Minor Road #N/A #N/A Low
Crescent Cl Minor Road High High High Yes
Dudley St Minor Road Low Medium Medium
Elizabeth Dr Minor Road #N/A #N/A Low
Gossips Rd Minor Road Low Medium Medium
Hillside Dr Minor Road #N/A Medium Medium
Hungry Head Rd Minor Road High High High Yes
Hungry Head Road Minor Road High High High Yes
Island Pl Minor Road #N/A #N/A Low
Jean Cl Minor Road #N/A #N/A Low
Karen St Minor Road Medium Medium Medium
Kylie St Minor Road #N/A #N/A Low
Marina Cr Minor Road Medium Medium Medium
Marshall Pl Minor Road #N/A #N/A Low
Martells Rd Minor Road High High High Yes
Melaleuca Pl Minor Road #N/A #N/A Low
Morgo St Minor Road High High High Yes
Newry Island Dr Minor Road High High High Yes
Old Punt Rd Minor Road High High High Yes
Orara St Minor Road #N/A #N/A Medium
Pacific Hwy Minor Road High High High Yes
Panorama Pde Minor Road #N/A Low Medium
Raleigh St Minor Road Medium Medium Medium
River St Minor Road Medium Medium Medium
Short Cut Rd Minor Road High High High Yes
South Arm Rd Minor Road High High High Yes
Titree St Minor Road Medium Medium Medium
Unnamed Road Minor Road High High High Yes
Urunga Lagoon Rd Minor Road High High High Yes
Valla St Minor Road Medium Medium Medium
Yellow Rock Rd Minor Road High High High Yes
North Coast Railway Railway Extreme Extreme Extreme Yes
Services
Gravity Main Sewer Services Extreme Extreme Extreme Yes
Pressure Main Sewer Services Extreme Extreme Extreme Yes
Private Pumping Main Sewer Services Extreme Extreme Extreme Yes
Rising Main Sewer Services Extreme Extreme Extreme Yes
Transfer Main Sewer Services High High High Yes
Urunga Wastewater Treatment Works Sewer Services #N/A #N/A Medium
Drainage Main Stormwater Services High High High Yes
Inter-allotment Drainage Main Stormwater Services High High High Yes
Water Line - Reticulation Main Water Services Medium Medium Medium
Water Line - Transfer Main Water Services Medium Medium Medium
Community Assets
North Hungry Head Beach - Beach Access (4WD) Beach Access Low Low Low
Back Creek (BCRCR) Parks, Reserves and Open Space Medium Medium Medium
Bellingen Coast Regional Crown Reserve (BCRCR) Parks, Reserves and Open Space Medium Medium Medium
Bellinger Heads State Park Parks, Reserves and Open Space Medium Medium Medium
Bellinger Keys - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Burrawong Parade - BSC Reserve Parks, Reserves and Open Space #N/A #N/A Low
Elizabeth Drive - BSC Reserve Parks, Reserves and Open Space #N/A #N/A Low
Graves x 2, Early Urunga Cemetery Parks, Reserves and Open Space #N/A #N/A Low
Maramba Park - BSC Reserve Parks, Reserves and Open Space Low Low Low
Marina Crescent - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Odalberree Drive - BSC Reserve Parks, Reserves and Open Space #N/A Low Low
Public Recreation Parks, Reserves and Open Space Medium Medium Medium
South Arm Road - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Stan Mile Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Unnamed BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Urunga Head Holiday Park & Cultural Planting Parks, Reserves and Open Space High High High Yes
Urunga Recreational Reserve Parks, Reserves and Open Space Low Low Low
Urunga Sandmass Parks, Reserves and Open Space Medium Medium Medium
Urunga Scouts - Bellinger Heads State Park Parks, Reserves and Open Space #N/A High High Yes
Yellow Rock Road - BSC Reserve Parks, Reserves and Open Space #N/A #N/A Low
Yellow Rock Road Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Public Recreation Land Parks, Reserves and Open Space Medium Medium Medium
Natural Assets
Foredune Beach and Dunes Low Low Low
Hind Dune Beach and Dunes Low Low Low
North Hungry Head Beach Beach and Dunes Low Low Low
Coastal Saltmarsh EEC Ecological Community High High High Yes
Freshwater Wetland EEC Ecological Community Extreme Extreme Extreme Yes
Littoral Rainforest EEC Ecological Community Extreme Extreme Extreme Yes
Mangrove Ecological Community Medium Medium Medium
Sub-tropical Coastal Floodplain Forest EEC Ecological Community Extreme Extreme Extreme Yes
Swamp Oak Floodplain Forest EEC Ecological Community Medium Medium Medium
Swamp Sclerophyll Forest EEC Ecological Community Extreme Extreme Extreme Yes
Environmental Conservation Environmental Protection Zone Medium Medium Medium
Environmental Management Environmental Protection Zone Medium Medium Medium
Heritage
Ellis Timber Mill Heritage (Archaeology Sites) Low Low Low
Former Urunga Bridge Heritage (Archaeology Sites) Medium Medium Medium
Graves x 2, Early Urunga Cemetery Heritage (Archaeology Sites) #N/A #N/A Low
Pedestrian Footbridge Heritage (Archaeology Sites) Medium Medium Medium
Ruined Drougher Heritage (Archaeology Sites) Low Low Low
Urunga Breakwater & Training Walls Heritage (Archaeology Sites) Low Low Low
Cultural Planting Heritage (Items) Medium Medium Medium
Cultural Planting - Christian Park Heritage (Items) Medium Medium Medium
House Heritage (Items) Medium Medium Medium
Pedestrian Footbridge Heritage (Items) Medium Medium Medium
Remnant Forest Heritage (Items) Low Low Low
Remnant Native Swamp Forest Heritage (Items) Low Low Low
Urunga Breakwater & Training Walls Heritage (Items) Low Low Low
Urunga Golf Club Heritage (Items) Medium Medium Medium
Urunga Recreational Reserve Heritage (Items) Low Low Low
Waterways
Bellinger River Waterway Low Low Low
Kalang River Waterway Low Low Low
Urunga Lagoon Waterway Low Low Low
RALEIGH Town Centre, Residential and Rural Property
Residential - Gordon Rd Residential Property #N/A #N/A Medium
Residential - Gurney St Residential Property #N/A #N/A Low
Residential - Old Pacific Highway Residential Property High High High Yes
Residential - Old Pacific Hwy Residential Property High High High Yes
Residential - Waterfall Way Residential Property Low Medium Medium
Rural - North Bank Rd Rural Property High High High Yes
Rural - Cabans Road Rural Property #N/A #N/A Low
Rural - McBaron Rd Rural Property #N/A #N/A Low
Rural - Waterfall Way Rural Property High High High Yes
Primary Production, Forestry and Industry
Raleigh Industrial Estate General Industrial Zone #N/A Low Medium
Primary Production - Brutons Rd Primary Production Low Medium Medium
Primary Production - Cabans Rd Primary Production #N/A #N/A Medium
Primary Production - Elizabeth St Primary Production #N/A #N/A Low
Primary Production - Gordon Rd (Lot 1) Primary Production #N/A #N/A Medium
Primary Production - Gurney St Primary Production #N/A #N/A Low
Primary Production - Keevers Dr Primary Production High High High Yes
Primary Production - McBaron Rd Primary Production #N/A #N/A Low
Primary Production - North Bank Rd Primary Production High High High Yes
Primary Production - Old Ferry Rd Primary Production High High High Yes
Primary Production - Old Pacific Hwy Primary Production #N/A #N/A Medium
Primary Production - Pacific Hwy Primary Production High High High Yes
Primary Production - Perrys Rd Primary Production High High High Yes
Primary Production - Public Road Primary Production High High High Yes
Primary Production - Queen St Primary Production High High High Yes
Primary Production - Short Cut Road Primary Production #N/A #N/A Medium
Primary Production - Valery Rd Primary Production High High High Yes
Primary Production - Victor St Primary Production #N/A #N/A Low
Primary Production - Walter St Primary Production #N/A #N/A Low
Primary Production - Waterfall Way Primary Production High High High Yes
Primary Production - Yellow Rock Rd Primary Production High High High Yes
Transport Infrastructure
Pacific Hwy Major Road Extreme Extreme Extreme Yes
Alice St Minor Road #N/A #N/A Low
Brutons Rd Minor Road #N/A Low Medium
Elizabeth St Minor Road #N/A #N/A Low
Gurney St Minor Road High High High Yes
Keevers Dr Minor Road High High High Yes
Mylestom Dr Minor Road High High High Yes
North Bank Rd Minor Road Medium Medium Medium
North St Minor Road #N/A #N/A Medium
Old Coast Rd Minor Road Medium Medium Medium
Old Pacific Hwy Minor Road High High High Yes
Pacific Hwy Minor Road High High High Yes
Queen St Minor Road High High High Yes
River St Minor Road High High High Yes
Short Cut Rd Minor Road #N/A #N/A Medium
Unnamed Road Minor Road High High High Yes
Valery Rd Minor Road High High High Yes
Victor St Minor Road #N/A #N/A Low
Walter St Minor Road #N/A #N/A Low
Yellow Rock Rd Minor Road High High High Yes
North Coast Railway Railway Extreme Extreme Extreme Yes
Services
Raleigh Waste Management Centre Waste Management Services #N/A #N/A High Yes
Private Pumping Main Sewer Services Extreme Extreme Extreme Yes
Rising Main Sewer Services Extreme Extreme Extreme Yes
Drainage Main Stormwater Services High High High Yes
Water Line - Reticulation Main Water (Mains) Services Medium Medium Medium
Water Line - Transfer Main Water (Mains) Services Medium Medium Medium
Community Assets
Raleigh Anglican Church (& Cultural Planting Heritage) Community Buildings #N/A #N/A Low
Raleigh Primary School (& Cultural Planting Heritage) Community Buildings #N/A #N/A Low
Bellingen Coast Regional Crown Reserve Parks, Reserves and Open Space Medium Medium Medium
Unnamed BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Yellow Rock Road Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Natural Assets
Coastal Saltmarsh EEC Ecological Community High High High Yes
Freshwater Wetland EEC Ecological Community Extreme Extreme Extreme Yes
Littoral Rainforest EEC Ecological Community Extreme Extreme Extreme Yes
Lowland Rainforest on Floodplain EEC Ecological Community Extreme Extreme Extreme Yes
Mangrove Ecological Community Medium Medium Medium
Sub-tropical Coastal Floodplain Forest EEC Ecological Community Extreme Extreme Extreme Yes
Swamp Sclerophyll Forest EEC Ecological Community Extreme Extreme Extreme Yes
Environmental Conservation Environmental Protection Zone Medium Medium Medium
Environmental Management Environmental Protection Zone Medium Medium Medium
Heritage
Kelly's Cow Bails Heritage (Archaeology Sites) Medium Medium Medium
Raleigh Butter Factory Heritage (Archaeology Sites) Medium Medium Medium
Silo Heritage (Archaeology Sites) #N/A Medium Medium
Urunga Breakwater & Training Walls Heritage (Archaeology Sites) Low Low Low
Yellow Rock Aboriginal Mission Cemetery Heritage (Archaeology Sites) Medium Medium Medium
Youngs Graves - Prince of Peace Courtyard Heritage (Archaeology Sites) #N/A #N/A Low
Anglican Church Heritage (Items) #N/A #N/A Low
Cultural Planting - 'Bonnie Doon' Heritage (Items) Medium Medium Medium
Cultural Planting - 'Greenlands' Heritage (Items) #N/A Low Low
Former Post Office Heritage (Items) #N/A #N/A Medium
House Heritage (Items) High High High Yes
Multiple Items (Farmhouse etc) Heritage (Items) High High High Yes
Osprey Nest Sites Heritage (Items) Low Low Low
Scenic View, Bellinger River bank Heritage (Items) Medium Medium Medium
Urunga Breakwater & Training Walls Heritage (Items) Low Low Low
Windbreak Heritage (Items) Medium Medium Medium
Waterways
Bellinger River Waterway Low Low Low
Boggey Creek Waterway Low Low Low
Kalang River Waterway Low Low Low
MYLESTOM Town Centre, Residential and Rural Property
Rural - Mylestom Drive Low Medium Medium
Rural - Tuckers Rock Road #N/A Medium Medium
Transport Infrastructure
George Street Minor Road High High High Yes
Mylestom Dr Minor Road High High High Yes
River St Minor Road High High High Yes
Unnamed Road Minor Road High High High Yes
Services
Drainage Main Stormwater Services Medium Medium Medium
Water Line - Reticulation Main Water (Mains) Services Low Low Low
Community Assets
Alma Doepel Reserve Parks, Reserves and Open Space Medium Medium Medium
Bellingen Coast Regional Crown Reserve Parks, Reserves and Open Space Medium Medium Medium
Bellinger Heads State Park Parks, Reserves and Open Space Medium Medium Medium
Mylestom Swimming Enclosure Public Recreation Land Low Low Low
Public Recreation Public Recreation #N/A #N/A Low
Natural Assets
Foredune Beach and Dunes Low Low Low
Hind Dune Beach and Dunes Low Low Low
Coastal Saltmarsh EEC Ecological Community Low Medium Medium
Littoral Rainforest EEC Ecological Community Extreme Extreme Extreme Yes
Mangrove Ecological Community Medium Medium Medium
Sub-tropical Coastal Floodplain Forest EEC Ecological Community Extreme Extreme Extreme Yes
Swamp Sclerophyll Forest EEC Ecological Community #N/A Medium High Yes
Environmental Management Environmental Protection Zone Medium Medium Medium
Heritage
Urunga Breakwater & Training Walls Heritage (Archaeology Sites) Low Low Low
Waterways
Bellingen River Waterway Low Low Low
REPTON Town Centre, Residential and Rural Property
Residential - Mylestom Drive Residential Property High High High Yes
Residential - River Street Residential Property #N/A Low Medium
Residential Zoned Land Residential Property High High High Yes
Rural - Bailey Street Rural Property High High High Yes
Rural - Lennox Street Rural Property #N/A Low Medium
Rural - Mylestom Drive Rural Property High High High Yes
Rural - Perrys Rd Rural Property High High High Yes
Rural - River Street Rural Property #N/A Low Medium
Rural - Smiths Road Rural Property #N/A Low Medium
Rural - Tuckers Rock Road Rural Property #N/A Low Medium
Rural - Woodward Street North Rural Property #N/A #N/A Low
Primary Production, Forestry and Industry
Primary Production - Mylestom Drive Primary Production High High High Yes
Transport Infrastructure
Bonville St Minor Road #N/A Low Medium
Caper St Minor Road #N/A Low Medium
Keevers Dr Minor Road High High High Yes
Lennox St Minor Road #N/A Low Medium
Mylestom Dr Minor Road High High High Yes
Raleigh St Minor Road #N/A #N/A Medium
River St Minor Road High High High Yes
Unnamed Road Minor Road #N/A Low Medium
Services
Water Line - Reticulation Main Water (Mains) Services Medium Medium Medium
Water Line - Transfer Main Water (Mains) Services Medium Medium Medium
Community Assets
Bellingen Coast Regional Crown Reserve Parks, Reserves and Open Space Medium Medium Medium
Bongil Bongil National Park Parks, Reserves and Open Space #N/A Low Low
Man Arm Creek Reserve - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Mylestom Drive - BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Unnamed BSC Reserve Parks, Reserves and Open Space Medium Medium Medium
Private Recreation Private Recreation Medium Medium Medium
Natural Assets
North Beach Beach and Dunes Low Low Low
Coastal Saltmarsh EEC Ecological Community High High High Yes
Freshwater Wetland EEC Ecological Community #N/A Medium High Yes
Sub-tropical Coastal Floodplain Forest EEC Ecological Community Extreme Extreme Extreme Yes
Swamp Sclerophyll Forest EEC Ecological Community #N/A Medium High Yes
Environmental Management Environmental Protection Zone #N/A Low Low
Heritage
Ruined Timber Mill Heritage (Archaeology Sites) High High High Yes
Smith and Moran Timber Mill Heritage (Archaeology Sites) Medium Medium Medium
House Heritage (Items) #N/A #N/A Low
Waterways
Bellinger River Waterway Low Low Low
BRIERFIELD Town Centre, Residential and Rural Property
Rural - Basin Rd Rural Landscape #N/A #N/A Low
Rural - Bowraville Rd Rural Landscape High High High Yes
Rural - Martells Rd Rural Landscape High High High Yes
Rural - Martells Road Rural Landscape Medium Medium Medium
Rural - South Arm Rd Rural Landscape High High High Yes
Rural - South Arm Road Rural Landscape High High High Yes
Rural Landscape Zoned Land Rural Landscape High High High Yes
Primary Production, Forestry and Industry
Forestry Land Forestry Zone Medium Medium Medium
Primary Production - Bowraville Rd Primary Production High High High Yes
Primary Production - Bowraville Road Primary Production High High High Yes
Primary Production - Hains Ln Primary Production High High High Yes
Primary Production - Martells Rd Primary Production High High High Yes
Primary Production - Martells Road Primary Production High High High Yes
Primary Production - South Arm Rd Primary Production High High High Yes
Primary Production - South Arm Road Primary Production High High High Yes
Primary Production Zoned Land Primary Production High High High Yes
Transport Infrastructure
Bowraville Rd Minor Road High High High Yes
Martells Rd Minor Road High High High Yes
South Arm Rd Minor Road High High High Yes
Unnamed Road Minor Road High High High Yes
Services
Drainage Main Stormwater Services Medium Medium Medium
Natural Assets
Freshwater Wetland EEC Ecological Community Extreme Extreme Extreme Yes
Lowland Rainforest EEC Ecological Community #N/A High High Yes
Lowland Rainforest on Floodplain EEC Ecological Community Extreme Extreme Extreme Yes
Swamp Sclerophyll Forest EEC Ecological Community Extreme Extreme Extreme Yes
Waterways
Kalang River Waterway Low Low Low
FERNMOUNT Town Centre, Residential and Rural Property
Residential - Maydwell St Residential Property Medium Medium Medium
Residential - Old Brierfield Rd Residential Property #N/A #N/A Low
Residential - Waterfall Way Residential Property Medium Medium Medium
Residential Zoned Land Residential Property Medium Medium Medium
Rural - Sweedmans Ln Rural Landscape #N/A #N/A Low
Rural - Waterfall Way Rural Landscape High High High Yes
Rural Landscape Zoned Land Rural Landscape High High High Yes
Primary Production, Forestry and Industry
Forestry Land Forestry Zone #N/A #N/A Low
Primary Production - Mount St Primary Production #N/A #N/A Medium
Primary Production - Nicholson St Primary Production High High High Yes
Primary Production - Old Brierfield Rd Primary Production #N/A #N/A Low
Primary Production - Public Road Primary Production High High High Yes
Primary Production - Sweedmans Ln Primary Production #N/A Low Medium
Primary Production - Tyson St Primary Production Low Medium Medium
Primary Production - Waterfall Way Primary Production High High High Yes
Primary Production Zoned Land Primary Production High High High Yes
Transport Infrastructure
Waterfall Way Major Road Extreme Extreme Extreme Yes
Baker St Minor Road High High High Yes
Bell St Minor Road Low #N/A #N/A
Main St Minor Road Low #N/A Medium
Maydwell St Minor Road Medium Medium Medium
Nicholson St Minor Road High High High Yes
Sweedmans Ln Minor Road #N/A #N/A Low
Unnamed Road Minor Road High High High Yes
Services
Water Line - Transfer Main Water (Mains) Services Medium Medium Medium
Community Assets
Car Park Community Facilities Low Low Low
Public Recreation Parks, Reserves and Open Space Medium Medium Medium
Natural Assets
Freshwater Wetland EEC Ecological Community Extreme Extreme Extreme Yes
Sub-tropical Coastal Floodplain Forest EEC Ecological Community Medium High High Yes
Swamp Sclerophyll Forest EEC Ecological Community Extreme Extreme Extreme Yes
Environmental Conservation Environmental Protection Zone Medium Medium Medium
Environmental Management Environmental Protection Zone Low Low Low
Heritage
Remnant Forest Heritage (Items) Medium Medium Medium
Stand of River Sheoak - Along Bellinger River Heritage (Items) Medium Medium Medium
Waterways
Bellingen River Waterway Low Low Low
VALERY Primary Production, Forestry and Industry
Forestry Land Forestry Low Low Low
Natural Assets
Freshwater Wetland EEC Ecological Community High High High Yes
BELLINGEN Town Centre, Residential and Rural Property
Rural - John Glyde Road Rural Landscape Low Medium Medium
Rural - North Bank Rd Rural Landscape High High High Yes
Rural - North Bank Road Rural Landscape High High High Yes
Rural - Public Intersection Rural Landscape #N/A #N/A Low
Rural - Public Road Rural Landscape High High High Yes
Rural - Slarkes Rd Rural Landscape High High High Yes
Rural - Slarkes Road Rural Landscape High High High Yes
Rural - Wheatley Street Rural Landscape High High High Yes
Rural Landscape Zoned Land Rural Landscape High High High Yes
Primary Production, Forestry and Industry
Forestry Land Forestry Medium Medium Medium
Primary Production - Cahill St Primary Production High High High Yes
Primary Production - Doepel St Primary Production Low #N/A Low
Primary Production - North Bank Rd Primary Production High High High Yes
Primary Production - North Bank Road Primary Production High High High Yes
Primary Production - Public Intersection Primary Production #N/A #N/A Low
Primary Production - Public Road Primary Production #N/A Medium Medium
Primary Production - Waterfall Way Primary Production High High High Yes
Primary Production - Wheatley Street Primary Production High High High Yes
Primary Production Zoned Land Primary Production High High High Yes
Transport Infrastructure
Infrastructure Zoned Land Infrastructure #N/A #N/A Low
Bridge St Minor / Local Road High High High Yes
Doepel St Minor / Local Road High High High Yes
John Glyde Road Minor / Local Road High High High Yes
North Bank Rd Minor / Local Road High High High Yes
Slarkes Rd Minor / Local Road High High High Yes
Unnamed Road Minor / Local Road High High High Yes
Waterfall Way Minor / Local Road #N/A #N/A Medium
Services
Rising Main Sewer Services Extreme Extreme Extreme Yes
Drainage Main Stormwater Services High High High Yes
Water Line - Reticulation Main Water (Mains) Services Medium Medium Medium
Community Assets
Public Recreation Community Facilities Medium Medium Medium
Private Recreation Community Facilities Medium Medium Medium
Natural Assets
Freshwater Wetland EEC Ecological Community Extreme Extreme Extreme Yes
Lowland Rainforest EEC Ecological Community #N/A #N/A High Yes
Lowland Rainforest on Floodplain EEC Ecological Community #N/A #N/A Medium
Environmental Conservation Environmental Protection Zone #N/A #N/A Low
Environmental Management Environmental Protection Zone #N/A #N/A Low
Heritage
Former Bellingen Bridge Heritage (Archaeological Sites) Low Low Low
Two Farm Cottages Heritage (Items) #N/A #N/A Low
Waterways
Bellinger River Waterway Low Low Low
Bellingen Shire Estuary Inundation Mapping D-3 Threatened Species Records
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Appendix D Threatened Species Records
Bellingen Shire Estuary Inundation Mapping D-4 Threatened Species Records
K:\n20222_Bellingen_EstuarySLR\docs\R.N20222.001.02.docx
Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Amphibian Crinia tinnula Wallum Froglet V,P
Found in a wide range of habitats, usually associated with acidic swamps on coastal sand plains. They occur in sedgelands, wet heathlands, paperbark swamps and drainage lines within other vegetation communities. They will also persist in disturbed areas. Breeds in swamps with permanent water as well as shallow ephemeral pools and drainage ditches.
High
Amphibian Litoria aurea Green and Golden Bell Frog
V
In NSW has been found in a wide range of water bodies except fast flowing streams. Inhabits many disturbed sites, including abandoned mines and quarries. Breeding habitat in NSW includes water bodies that are still, shallow, ephemeral, unpolluted (but the frog can be found in polluted habitats), unshaded, with aquatic plants and free of Mosquito Fish (Gambusia holbrooki) and other predatory fish, with terrestrial habitats that consisted of grassy areas and vegetation no higher than woodlands, and a range of diurnal shelter sites.
High
Amphibian Litoria booroolongensis Booroolong Frog E
The species is associated with the following vegetation associations: wet sclerophyll forests (shrubby and grassy sub-formation); dry sclerophyll forest (shrub/grass and shrubby sub-formation); grassy woodland; heathland; forested wetland; freshwater wetland; rainforest and cleared grazing land and pasture.
High
Amphibian Mixophyes iteratus Giant Barred Frog E1,P,2 E
Occurs in uplands and lowlands in rainforest and wet sclerophyll forest, including farmland. Populations have been found in disturbed areas with vegetated riparian strips on cattle farms and in regenerated logged areas. Many known habitats are the lower reaches of streams which have been affected by major disturbances such as clearing, timber harvesting and urban development in their headwaters.
High
Amphibian Mixophyes balbus Stuttering Frog V
Typically found in association with permanent streams through temperate and sub-tropical rainforest and wet sclerophyll forest, rarely in dry open tableland riparian vegetation, and also in moist gullies in dry forest
Medium
Bird Actitis hypoleucos Common Sandpiper P migratory
Utilises a wide range of coastal wetlands and some inland wetlands, with varying levels of salinity, and is mostly found around muddy margins or rocky shores and rarely on mudflats. Has been recorded in estuaries and deltas of streams, as well as on banks farther upstream; around lakes, pools, billabongs, reservoirs, dams and claypans, and occasionally piers and jetties. The muddy margins utilised by the species are often narrow, and may be steep. The species is often associated with mangroves, and sometimes found in areas of mud littered with rocks or snags.
High
Bird Anthochaera phrygia Regent Honeyeater E4A,P E
Mostly occur in dry Box-Ironbark eucalypt woodland and dry sclerophyll forest associations in areas of low to moderate relief, wherein they prefer moister, more fertile sites available, for example along creek flats, or in broad river valleys and foothills. In NSW, riparian forests containing River Oak (Casuarina cunninghamiana), and with Needle-leaf Mistletoe (Amyema cambagei), are also important for feeding and breeding.
High
Bellingen Shire Estuary Inundation Mapping D-5 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Apus pacificus Fork-tailed Swift migratory
They mostly occur over dry or open habitats, including riparian woodland and tea-tree swamps, low scrub, heathland or saltmarsh. They are also found at treeless grassland and sandplains covered with spinifex, open farmland and inland and coastal sand-dunes. The sometimes occur above rainforests, wet sclerophyll forest or open forest or plantations of pines.
Medium
Bird Ardea ibis Cattle Egret P migratory
Occurs in tropical and temperate grasslands, wooded lands and terrestrial wetlands. High numbers observed in moist, low-lying poorly drained pastures with an abundance of high grass; it avoids low grass pastures. It has been recorded on earthen dam walls and ploughed fields.
High
Bird Ardea alba Great Egret migratory
Wetland habitats such as inland and coastal, freshwater and saline, permanent and ephemeral, open and vegetated, large and small, natural and artificial. These include swamps and marshes; margins of rivers and lakes; damp or flooded grasslands, pastures or agricultural lands; reservoirs; sewage treatment ponds; drainage channels; salt pans and salt lakes; salt marshes; estuarine mudflats, tidal streams; mangrove swamps; coastal lagoons; and offshore reefs.
High
Bird Ardenna pacificus Wedge-tailed Shearwater P J A pelagic, marine bird known from tropical and subtropical waters. Low
Bird Botaurus poiciloptilus Australasian Bittern E1,P E
Inhabits temperate freshwater wetlands and occasionally estuarine reedbeds. The species favours permanent shallow waters, or edges of pools and waterways, with tall, dense vegetation such as sedges, rushes and reeds on muddy or peaty substrate
High
Bird Calidris acuminata Sharp-tailed Sandpiper P migratory
Prefers muddy edges of shallow fresh or brackish wetlands, with inundated or emergent sedges, grass, saltmarsh or other low vegetation, including lagoons, swamps, lakes and pools near the coast, and dams, waterholes, soaks, bore drains and bore swamps, saltpans and hypersaline saltlakes inland. They also occur in saltworks and sewage farms. They use flooded paddocks, sedgelands and other ephemeral wetlands, but leave when they dry. They use intertidal mudflats in sheltered bays, inlets, estuaries or seashores, and also swamps and creeks lined with mangroves. They tend to occupy coastal mudflats mainly after ephemeral terrestrial wetlands have dried out, moving back during the wet season.
High
Bird Calidris ferruginea Curlew Sandpiper E1,P migratory
Mainly occur on intertidal mudflats in sheltered coastal areas, such as estuaries, bays, inlets and lagoons, and also around non-tidal swamps, lakes and lagoons near the coast, and ponds in saltworks and sewage farms. They are also recorded inland, though less often, including around ephemeral and permanent lakes, dams, waterholes and bore drains, usually with bare edges of mud or sand. They occur in both fresh and brackish waters. Occasionally they are recorded around floodwaters.
High
Bird Calyptorhynchus lathami Glossy Black-Cockatoo V,P,2
Open forest and woodlands of the coast and the Great Dividing Range. Allocasuarina littoralis and A. torulosa are important foods. Low
Bird Catharacta skua Great Skua marine Ocean Waters. Low
Bellingen Shire Estuary Inundation Mapping D-6 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Charadrius leschenaultii Greater Sand-plover V,P migratory
Almost entirely coastal, inhabiting littoral and estuarine habitats. Mainly occur on sheltered sandy, shelly or muddy beaches with large intertidal mudflats or sandbanks, as well as sandy estuarine lagoons and inshore reefs, rock platforms, small rocky islands or sand cays on coral reefs. Occasionally recorded on near-coastal saltworks and saltlakes, including marginal saltmarsh, and on brackish swamps. They seldom occur at shallow freshwater wetlands.
High
Bird Coracina lineata Barred Cuckoo-shrike V,P
Rainforest, eucalypt forests and woodlands, clearings in secondary growth, swamp woodlands and timber along watercourses. Medium
Bird Daphoenositta chrysoptera Varied Sittella V,P
Inhabits eucalypt forests and woodlands, especially rough-barked species and mature smooth-barked gums with dead branches, mallee and Acacia woodland.
Low
Bird Dasyornis brachypterus Eastern bristlebird E Inhabits low dense vegetation in a broad range of habitat types including sedgeland, heathland, swampland, shrubland, sclerophyll forest and woodland, and rainforest.
High
Bird Diomedea antipodensis Albatross migratory Ocean waters. Low
Bird Diomedea dabbenena Albatross migratory Ocean waters. Low
Bird Diomedea epomophora epomophora Albatross V Ocean waters. Low
Bird Diomedea epomophora sanfordi Albatross E Ocean waters. Low
Bird Diomedea exulans antipodensis Albatross V
Ocean waters. Low
Bird Diomedea exulans exulans Albatross E Ocean waters. Low
Bird Diomedea exulans gibsoni Albatross V Ocean waters. Low
Bird Diomedea exulans (sensu lato) Albatross V Ocean waters. Low
Bird Diomedea sanfordi Albatross migratory Ocean waters. Low
Bird Diomedea sanfordi Albatross migratory Ocean waters. Low
Bird Ephippiorhynchus asiaticus Black-necked Stork E1,P
Mainly found on shallow, permanent, freshwater terrestrial wetlands, and surrounding marginal vegetation, including swamps, floodplains, watercourses and billabongs, freshwater meadows, wet heathland, farm dams and shallow floodwaters, as well as extending into adjacent grasslands, paddocks and open savannah woodlands. They also forage within or around estuaries and along intertidal shorelines, such as saltmarshes, mudflats and sandflats, and mangrove vegetation.
High
Bellingen Shire Estuary Inundation Mapping D-7 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Erythrotriorchis radiatus Red Goshawk CE V
Inhabit open woodland and forest, preferring a mosaic of vegetation types, a large population of birds as a source of food, and permanent water, and are often found in riparian habitats along or near watercourses or wetlands. In NSW, preferred habitats include mixed subtropical rainforest, Melaleuca swamp forest and riparian Eucalyptus forest of coastal rivers.
Medium
Bird Esacus magnirostris Beach Stone-curlew E4A,P
Found exclusively along the coast, on a wide range of beaches, islands, reefs and in estuaries, and may often be seen at the edges of or near mangroves. They forage in the intertidal zone of beaches and estuaries, on islands, flats, banks and spits of sand, mud, gravel or rock, and among mangroves. Breed above the littoral zone, at the backs of beaches, or on sandbanks and islands, among low vegetation of grass, scattered shrubs or low trees; also among open mangroves.
High
Bird Fregetta grallaria grallaria
White-bellied storm petrel V Ocean waters. Low
Bird Gallinago hardwickii Latham's Snipe migratory
Permanent and ephemeral wetlands. They usually inhabit open, freshwater wetlands with low, dense vegetation (e.g. swamps, flooded grasslands or heathlands, around bogs and other water bodies). However, they can also occur in habitats with saline or brackish water, in modified or artificial habitats, and in habitats located close to humans or human activity.
High
Bird Gallinago megala Swinhoe's Snipe migratory
Habitat includes the dense clumps of grass and rushes round the edges of fresh and brackish wetlands. This includes swamps, billabongs, river pools, small streams and sewage ponds. They are also found in drying claypans and inundated plains pitted with crab holes.
High
Bird Gallinago stenura Pin-tailed snipe migratory
During non-breeding period the Pin-tailed Snipe occurs most often in or at the edges of shallow freshwater swamps, ponds and lakes with emergent, sparse to dense cover of grass/sedge or other vegetation. The species is also found in drier, more open wetlands such as claypans in more arid parts of species' range. It is also commonly seen at sewage ponds; not normally in saline or inter-tidal wetlands.
High
Bird Glossopsitta pusilla Little Lorikeet V,P
Forages primarily in the canopy of open Eucalyptus forest and woodland, yet also finds food in Angophora, Melaleuca and other tree species. Riparian habitats are particularly used, due to higher soil fertility and hence greater productivity.
Medium
Bird Grus rubicunda Brolga V,P
Often feed in dry grassland or ploughed paddocks or even desert claypans. Are dependent on wetlands especially shallow swamps. Medium
Bird Haematopus fuliginosus Sooty Oystercatcher V,P Nest on beaches and in estuaries and forage between the high and low water mark. High
Bird Haematopus longirostris Pied Oystercatcher E1,P Nest on beaches and in estuaries and forage between the high and low water mark. High
Bellingen Shire Estuary Inundation Mapping D-8 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Haliaeetus leucogaster White-bellied sea eagle P migratory
Mostly recorded in coastal lowlands and around terrestrial wetlands in tropical and temperate regions of mainland Australia and its offshore islands. Habitats characterised by the presence of large areas of open water (larger rivers, swamps, lakes, the sea). Also occur at sites near the sea or sea-shore, such as around bays and inlets, beaches, reefs, lagoons, estuaries and mangroves. Terrestrial habitats include coastal dunes, tidal flats, grassland, heathland, woodland, forest (including rainforest) and even urban areas.
Medium
Bird Hieraaetus morphnoides Little Eagle V,P Occupies habitats rich in prey within open eucalypt forest, woodland or open woodland. Low
Bird Hirundapus caudacutus White-throated Needletail
P migratory
Almost exclusively aerial, recorded most often above wooded areas, including open forest and rainforest, and may also fly between trees or in clearings, below the canopy, but they are less commonly recorded flying above woodland). They also commonly occur over heathland but less often over treeless areas, such as grassland or swamps.
Low
Bird Hydroprogne caspia Caspian Tern P migratory
Mostly found in sheltered coastal embayments (harbours, lagoons, inlets, bays, estuaries and river deltas) and those with sandy or muddy margins are preferred. They also occur on near-coastal or inland terrestrial wetlands that are either fresh or saline, especially lakes (including ephemeral lakes), waterholes, reservoirs, rivers and creeks. They also use artificial wetlands, including reservoirs, sewage ponds and saltworks. In offshore areas the species prefers sheltered situations, particularly near islands, and is rarely seen beyond reefs.
High
Bird Irediparra gallinacea Comb-crested Jacana V,P
Inhabit permanent freshwater wetlands, either still or slow-flowing, with a good surface cover of floating vegetation, especially water-lilies, or fringing and aquatic vegetation.
High
Bird Ixobrychus flavicollis Black Bittern V,P
Inhabits both terrestrial and estuarine wetlands, generally in areas of permanent water in flooded grassland, forest, woodland, rainforest and mangroves.
High
Bird Lathamus discolor Swift Parrot E
Inhabits dry sclerophyll eucalypt forests and woodlands. It occasionally occurs in wet sclerophyll forests. Predominantly forages within habitats that have been so significantly cleared that they are classified as endangered ecological communities.
Low
Bird Lichenostomus fasciogularis Mangrove Honeyeater V,P
Primary habitat of the species is mangrove woodlands and shrublands but also range into adjacent forests, woodlands and shrublands, including casuarina and paperbark swamp forests and associations dominated by eucalypts or banksias.
High
Bird Limosa lapponica Bar-tailed Godwit P migratory
Found mainly in coastal habitats such as large intertidal sandflats, banks, mudflats, estuaries, inlets, harbours, coastal lagoons and bays. It is found often around beds of seagrass and, sometimes, in nearby saltmarsh. It has been sighted in coastal sewage farms and saltworks, saltlakes and brackish wetlands near coasts, sandy ocean beaches, rock platforms, and coral reef-flats. It is rarely found on inland wetlands or in areas of short grass, such as farmland, paddocks and airstrips.
High
Bellingen Shire Estuary Inundation Mapping D-9 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Lophoictinia isura Square-tailed Kite V,P,3
Inhabits coastal and subcoastal, eucalypt-dominated open forests and woodlands, coastal heathlands, and often near openings and edges of forest.
Medium
Bird Macronectes giganteus Southern Giant Petrel E Ocean waters. Low
Bird Macronectes halli Northern Giant Petrel V Ocean waters. Low
Bird Merops ornatus Rainbow Bee-eater P migratory
Occurs mainly in open forests and woodlands, shrublands, and in various cleared or semi-cleared habitats, including farmland and areas of human habitation. Usually occurs in open, cleared or lightly-timbered areas that are often, but not always, located in close proximity to permanent water. Also occurs in inland and coastal sand dune systems, and in mangroves in northern Australia, and has been recorded in various other habitat types including heathland, sedgeland, vine forest and vine thicket, and on beaches.
Medium
Bird Monarcha melanopsis Black-faced Monarch migratory
Mainly occurs in rainforest ecosystems, including semi-deciduous vine-thickets, complex notophyll vine-forest, tropical (mesophyll) rainforest, subtropical (notophyll) rainforest, mesophyll (broadleaf) thicket/shrubland, warm temperate rainforest, dry (monsoon) rainforest and (occasionally) cool temperate rainforest.
Medium
Bird Monarcha trivirgatus Spectacled Monarch migratory Subtropical or tropical moist lowland forests, subtropical or tropical mangrove forests, and subtropical or tropical moist montane forests. Medium
Bird Myiagra cyanoleuca Satin Flycatcher migratory Inhabit heavily vegetated gullies in eucalypt-dominated forests and taller woodlands, and on migration, occur in coastal forests, woodlands, mangroves and drier woodlands and open forests
Medium
Bird Ninox strenua Powerful Owl V,P,3
Inhabits a range of vegetation types, from woodland and open sclerophyll forest to tall open wet forest and rainforest. It requires large tracts of forest or woodland habitat but can occur in fragmented landscapes as well.
Low
Bird Numenius madagascariensis Eastern Curlew P migratory
Most commonly associated with sheltered coasts, especially estuaries, bays, harbours, inlets and coastal lagoons, with large intertidal mudflats or sandflats, often with beds of seagrass. Occasionally, the species occurs on ocean beaches (often near estuaries), and coral reefs, rock platforms, or rocky islets. The birds are often recorded among saltmarsh and on mudflats fringed by mangroves, and sometimes use the mangroves. The birds are also found in saltworks and sewage farms.
High
Bird Numenius phaeopus Whimbrel P migratory
Often found on the intertidal mudflats of sheltered coasts. It is also found in harbours, lagoons, estuaries and river deltas, often those with mangroves, but also open, unvegetated mudflats. It is occasionally found on sandy or rocky beaches, on coral or rocky islets, or on intertidal reefs and platforms. It has been infrequently recorded using saline or brackish lakes near coastal areas. It also used saltflats with saltmarsh, or saline grasslands with standing water left after high spring-tides, and in similar habitats in sewage farms and saltfields.
High
Bellingen Shire Estuary Inundation Mapping D-10 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Numenius minutus Little Curlew migratory
Pools, river beds and water-filled tidal channels, and shallow water at edges of billabongs. The species prefers pools with bare dry mud (including mudbanks in shallow water) and they do not use pools if they are totally dry, flooded or heavily vegetated.
High
Bird Oxyura australis Blue-billed Duck V,P Prefers deep water in large permanent wetlands and swamps with dense aquatic vegetation. High
Bird Pandion cristatus Eastern Osprey V,P,3
Occur in littoral and coastal habitats and terrestrial wetlands of tropical and temperate Australia and offshore islands. Require extensive areas of open fresh, brackish or saline water for foraging. Frequent a variety of wetland habitats including inshore waters, reefs, bays, coastal cliffs, beaches, estuaries, mangrove swamps, broad rivers, reservoirs and large lakes and waterholes.
Medium
Bird Pandion haliaetus Osprey migratory
Occur in littoral and coastal habitats and terrestrial wetlands of tropical and temperate Australia and offshore islands. They are mostly found in coastal areas but occasionally travel inland along major rivers. They require extensive areas of open fresh, brackish or saline water for foraging and frequent a variety of wetland habitats including inshore waters, reefs, bays, coastal cliffs, beaches, estuaries, mangrove swamps, broad rivers, reservoirs and large lakes and waterholes.
Medium
Bird Plegadis falcinellus Glossy Ibis P migratory
Preferred habitat for foraging and breeding are fresh water marshes at the edges of lakes and rivers, lagoons, flood-plains, wet meadows, swamps, reservoirs, sewage ponds, rice-fields and cultivated areas under irrigation. The species is occasionally found in coastal locations such as estuaries, deltas, saltmarshes and coastal lagoons.
Medium
Bird Pluvialis fulva Pacific Golden Plover P migratory
Usually inhabits coastal habitats, though it occasionally occurs around inland wetlands. Occur on beaches, mudflats and sandflats (sometimes in vegetation such as mangroves, low saltmarsh such as Sarcocornia, or beds of seagrass) in sheltered areas including harbours, estuaries and lagoons, and also in evaporation ponds in saltworks. The species is also sometimes recorded on islands, sand and coral cays and exposed reefs and rocks. They are less often recorded in terrestrial habitats, usually wetlands such as fresh, brackish or saline lakes, billabongs, pools, swamps and wet claypans, especially those with muddy margins and often with submerged vegetation or short emergent grass. Other terrestrial habitats inhabited include short (or, occasionally, long) grass in paddocks, crops or airstrips, or ploughed or recently burnt areas, and they are very occasionally recorded well away from water.
High
Bird Pomatostomus temporalis temporalis
Grey-crowned Babbler (eastern subspecies) V,P
Inhabits open Box Woodlands on alluvial plains. Low
Bird Pterodroma leucoptera leucoptera Gould's Petrel E Ocean waters. Low
Bird Pterodroma neglecta neglecta Kermadec Petrel V Ocean waters. Low
Bellingen Shire Estuary Inundation Mapping D-11 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Ptilinopus magnificus Wompoo Fruit-Dove V,P
Occurs in patches of subtropical rainforest and adjoining wet sclerophyll habitats but has also been recorded using single trees in farmland. Most abundant in warmer, mature rainforests dominated by Ficus spp..
Medium
Bird Ptilinopus regina Rose-crowned Fruit-Dove V,P
Occur mainly in sub-tropical and dry rainforest and occasionally in moist eucalypt forest and swamp forest, where fruit is plentiful. Medium
Bird Puffinus carneipes Flesh-footed Shearwater migratory Over continental shelves and slopes and occasionally inshore waters. Breed on islands in burrows on sloping ground in coastal forest, scrubland, shrubland or grassland.
Low
Bird Puffinus leucomelas Streaked Shearwater migratory Ocean waters, cliffs. Low
Bird Rhipidura rufifrons Rufous Fantail
Wet sclerophyll forests, often in gullies dominated by eucalypts usually with a dense shrubby understorey often including ferns. They also occur in subtropical and temperate rainforests. Occasionally occur in secondary regrowth.
Medium
Bird Rostratula australis Australian Painted Snipe E
Inhabits shallow terrestrial freshwater (occasionally brackish) wetlands, including temporary and permanent lakes, swamps and claypans. They also use inundated or waterlogged grassland or saltmarsh, dams, rice crops, sewage farms and bore drains. Typical sites include those with rank emergent tussocks of grass, sedges, rushes or reeds, or samphire; often with scattered clumps of lignum Muehlenbeckia or canegrass or sometimes tea-tree (Melaleuca). The Australian Painted Snipe sometimes utilises areas that are lined with trees, or that have some scattered fallen or washed-up timber.
High
Bird Rostratula benghalensis (sensu lato) Painted Snipe E
Inhabits shallow terrestrial freshwater (occasionally brackish) wetlands, including temporary and permanent lakes, swamps and claypans. They also use inundated or waterlogged grassland or saltmarsh, dams, rice crops, sewage farms and bore drains. Typical sites include those with rank emergent tussocks of grass, sedges, rushes or reeds, or samphire; often with scattered clumps of lignum Muehlenbeckia or canegrass or sometimes tea-tree (Melaleuca). The Australian Painted Snipe sometimes utilises areas that are lined with trees, or that have some scattered fallen or washed-up timber.
High
Bird Stagonopleura guttata Diamond Firetail V,P
Found in grassy eucalypt woodlands, including Box-Gum Woodlands and Snow Gum Eucalyptus pauciflora Woodlands. Also occurs in open forest, mallee, Natural Temperate Grassland, and in secondary grassland derived from other communities. Often found in riparian areas (rivers and creeks), and sometimes in lightly wooded farmland.
Low
Bellingen Shire Estuary Inundation Mapping D-12 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Bird Sterna hirundo Common Tern P migratory
Marine, pelagic and coastal. In Australia, they are recorded in all marine zones, but are commonly observed in near-coastal waters, both on ocean beaches, platforms and headlands and in sheltered waters, such as bays, harbours and estuaries with muddy, sandy or rocky shores. Occasionally they are recorded in coastal and near-coastal wetlands, either saline or freshwater, including lagoons, rivers, lakes, swamps and saltworks. Sometimes they occur in mangroves or saltmarsh and, in bad weather, in coastal sand-dunes or coastal embayments.
High
Bird Sternula albifrons Little Tern E1,P migratory
Inhabit sheltered coastal environments, including lagoons, estuaries, river mouths and deltas, lakes, bays, harbours and inlets, especially those with exposed sandbanks or sand-spits, and also on exposed ocean beaches. Nest on sand-spits, banks, ridges or islets in sheltered coastal environments, such as coastal lakes, estuaries and inlets, and also on wide and flat or gently sloping sandy ocean beaches, and also, occasionally, in sand-dunes. Forage in shallow waters of estuaries, coastal lagoons and lakes, frequently over channels next to spits and banks or entrances, and often close to breeding colonies. Roost or loaf on sand-spits, banks and bars within sheltered estuarine or coastal environments, or on the sandy shores of lakes and ocean beaches.
High
Bird Thalassarche bulleri Buller's Albatross
V migratory Ocean waters. Low
Bird Thalassarche cauta cauta Shy Albatross V migratory Ocean waters. Low
Bird Thalassarche cauta salvini Salvin's Albatross V migratory
Ocean waters. Low
Bird Thalassarche cauta steadi White-capped Albatross V migratory Ocean waters. Low
Bird Thalassarche cauta (sensu stricto) Shy Albatross V migratory Ocean waters. Low
Bird Thalassarche eremita Chatham Albatross
E migratory Ocean waters. Low
Bird Thalassarche impavida Campbell Albatross V migratory Ocean waters. Low
Bird Thalassarche melanophris Black-browed Albatross V migratory Ocean waters. Low
Bird Thalassarche melanophris impavida Campbell Albatross V migratory Ocean waters. Low
Bird Thalassarche salvini Salvin's Albatross V migratory Ocean waters. Low
Bird Thalassarche steadi White-capped Albatross V migratory Ocean waters. Low
Bird Tyto longimembris Eastern Grass Owl V,P,3
Found in areas of tall grass, including grass tussocks, in swampy areas, grassy plains, swampy heath, and in cane grass or sedges on flood plains. Medium
Bird Tyto novaehollandiae Masked Owl V,P,3
Eucalypt forests and woodlands on the coast. Medium
Bird Tyto tenebricosa Sooty Owl V,P,3
Occurs in rainforest, including dry rainforest, subtropical and warm temperate rainforest, as well as moist eucalypt forests. Medium
Bellingen Shire Estuary Inundation Mapping D-13 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Fish Acentronura tentaculata
marine Found on tropical inshore reefs. Also occurs in temperate waters associated with shallow sandflats in protected and somewhat silty coastal areas among sparse low plant growth and in algae on rocks.
Medium
Fish Carcharias taurus (east coast population) Grey Nurse Shark CE
Ocean Waters. Low
Fish Carcharodon carcharias Great White Shark V Ocean Waters. Low
Fish Epinephelus daemelii Black Rockcod V Ocean Waters. Low
Fish Festucalex cinctus Girdled Pipefish marine In association with seagrass, kelp, boulders, rocky reefs, rocks, shell rubble, sand, silt and mud. Medium
Fish Filicampus tigris Tiger Pipefish marine Ocean Waters. Low
Fish Heraldia nocturna Upside-down Pipefish marine Ocean Waters. Low
Fish Hippichthys heptagonus Madura Pipefish marine Ocean Waters. Low
Fish Hippichthys penicillus Beady Pipefish marine Ocean Waters. Low
Fish Hippocampus whitei White's Seahorse
marine Ocean Waters. Low
Fish Histiogamphelus briggsii Crested Pipefish
marine Ocean Waters. Low
Fish Lamna nasus Porbeagal marine Ocean Waters. Low
Fish Lissocampus runa Javelin Pipefish marine Ocean Waters. Low
Fish Manta birostris Giant Manta Ray marine Ocean Waters. Low
Fish Maroubra perserrata Sawtooth Pipefish marine Ocean Waters. Low
Fish Pristis zijsron Green Sawfish V Ocean Waters. Low
Fish Rhincodon typus Whale Shark V Ocean Waters. Low
Fish Solegnathus dunckeri Duncker's Pipehorse marine Ocean waters. Low
Fish Solegnathus spinosissimus Spiny Pipehorse
marine Ocean waters. Low
Fish Solenostomus cyanopterus Robust Ghostpipefish marine Ocean waters. Low
Fish Solenostomus paegnius Rough Snout Ghostpipefish marine Ocean waters. Low
Fish Solenostomus paradoxus Ornate Ghostpipefish marine
Ocean waters. Low
Fish Stigmatopora nigra Widebody Pipefish marine Ocean waters. Low
Fish Syngnathoides biaculeatus Double-end Pipehorse
marine Ocean waters. Low
Fish Trachyrhamphus bicoarctatus Bentstick Pipefish marine Ocean waters. Low
Fish Urocampus carinirostris Hairy Pipefish marine Ocean waters. Low
Fish Vanacampus margaritifer Mother-of-pearl Pipefish marine Ocean waters. Low
Bellingen Shire Estuary Inundation Mapping D-14 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Flora Arthraxon hispidus Hairy-joing Grass V Moisture and shade-loving grass, found in or on the edges of rainforest and in wet eucalypt forest, often near creeks or swamps. Medium
Flora Cryptostylis hunteriana Leafless tongue-orchid V
Heathy woodlands, sedgelands, Xanthorrheoa spp. plains, dry sclerophyll forests (shrub/grass sub-formation and shrubby sub-formation), forested wetlands, freshwater wetlands, grasslands, grassy woodlands, rainforests and wet sclerophyll forests. Soils are generally considered to be moist and sandy, however, this species is also known to grow in dry or peaty soils.
Medium
Flora Cynanchum elegans White-flowered Wax Plant E
Occurs on a variety of lithologies and soil types, usually on steep slopes with varying degrees of soil fertility. Occurs mainly at the ecotone between dry subtropical rainforest and sclerophyll forest/woodland communities.
Low
Flora Dendrobium melaleucaphilum Spider orchid E1,P,2
Grows frequently on Melaleuca styphelioides, less commonly on rainforest trees or on rocks in coastal districts. High
Flora Marsdenia longiloba Slender Marsdenia V Subtropical and warm temperate rainforest, lowland moist eucalypt forest adjoining rainforest and, sometimes, in areas with rock outcrops. Medium
Flora Parsonsia dorrigoensis Milky Silkpod V,P E Found in subtropical and warm-temperature rainforest, on rainforest margins, and in moist eucalypt forest up to 800 m, on brown clay soils. Medium
Flora Phaius australis Lesser Swamp-orchid
Freshwater wetlands. High
Flora Streblus pendulinus Siah's Backbone E
Warmer rainforests, chiefly along watercourses. The altitudinal range is from near sea level to 800 m above sea level. The species grows in well developed rainforest, gallery forest and drier, more seasonal rainforest.
Medium
Flora Thesium australe Austral Toadflax V
Semi-parasitic on roots of a range of grass species notably Kangaroo Grass. Occurs in subtropical, temperate and subalpine climates over a wide range of altitudes on soils derived from sedimentary, igneous and metamorphic geology on a range of soils including black clay loams to yellow podzolics and peaty loams. Occurs in shrubland, grassland or woodland, often on damp sites.
Medium
Flora Tylophora woollsii E Grows in wet sclerophyll forest and rainforest Medium
Flora Zieria prostrata E Grows mainly in exposed southerly aspects on headlands in low coastal heathland or sod grassland. Low
Flora Acacia chrysotricha Newry Golden Wattle E1,P
An understorey species on rainforest edges and in wet or dry eucalypt forest in steep narrow gullies on quartzite soils. Medium
Flora Acronychia littoralis Scented Acronychia E1,P E A range of littoral rainforest communities on sand and meta-sedimentary clays, and also Brush Box wet sclerophyll forest on meta-sedimentary clays High
Flora Allocasuarina defungens Dwarf Heath Casuarina E E Grows mainly in tall heath on sand, but can also occur on clay soils and sandstone. Also extends onto exposed nearby-coastal hills or headlands adjacent to sandplains.
Medium
Bellingen Shire Estuary Inundation Mapping D-15 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Flora Hicksbeachia pinnatifolia Red Boppel Nut V,P V
Understorey tree in subtropical rainforest, regrowth rainforest, moist eucalypt forest and Brush Box forest. Grows up to 500 m altitude, sometimes extending into nearby wet sclerophyll forest with closed understorey. Usually grows on flat to gently inclined valley flats to steeply inclined slopes and on hillcrests. The soils are mostly slightly acid loams or clay loams and derived from a range of substrates particularly basalt derived soils.
Medium
Flora Macadamia integrifolia Macadamia Nut P V Subtropical rainforest and complex notophyll vineforest, at the margins of these forests and in mixed sclerophyll forest. Medium
Flora Niemeyera whitei Rusty Plum, Plum Boxwood
V,P
Rainforest and the adjacent understorey of moist eucalypt forest. Medium
Insect Phyllodes imperialis smithersi Pink Underwing Moth E
Found below the altitude of 600 m in undisturbed, subtropical rainforest. It occurs in association with the vine Carronia multisepalea, a collapsed shrub that provides the food and habitat the moth requires in order to breed.
Medium
Mammal Arctocephalus forsteri New Zealand Fur-seal V,P
The species utilises rocky habitat as breeding and haul-out sites and appears to avoid open rock platforms and sandy or pebbly beaches. Low
Mammal Arctocephalus pusillus doriferus Australian Fur-seal V,P
Prefers the rocky parts of islands. For foraging, the Australian Fur-seal prefers to utilise oceanic waters of the continental shelf and generally does not dive deeper than 150 m.
Low
Mammal Chalinolobus dwyeri Long-eared Pied Bat V
Sandstone cliffs and fertile woodland valley habitat within close proximity of each other is important. Habitat types inlcude rainforest and moist eucalypt forest habitats on other geological substrates. Requires a combination of sandstone cliff/escarpment to provide roosting habitat that is adjacent to higher fertility sites, particularly box gum woodlands or river/rainforest corridors which are used for foraging.
Medium
Mammal Dasyurus maculatus Spotted-tailed Quoll V,P E Preference for mature wet forest habitat especially in areas with rainfall 600 mm/year. Unlogged forest or forest that has been less disturbed by timber harvesting is also preferable.
Medium
Mammal Delphinus delphis Common dolphin marine Ocean Waters. Low
Mammal Eubalaena australis Southern Right Whale
E Ocean Waters. Low
Mammal Grampus griseus Risso's Dolphin
migratory Ocean Waters. Low
Mammal Lagenorhynchus obscurus Dusky Dolphin marine Ocean Waters. Low
Mammal Megaptera novaeangliae Humpback Whale V migratory marine
Ocean Waters. Low
Mammal Miniopterus australis Little Bentwing-bat V,P
Moist eucalypt forest, rainforest, vine thicket, wet and dry sclerophyll forest, Melaleuca swamps, dense coastal forests and banksia scrub. Roost in caves, tunnels, tree hollows, abandoned mines, stormwater drains, culverts, bridges and sometimes buildings during the day, and at night forage for small insects beneath the canopy of densely vegetated habitats.
Medium
Bellingen Shire Estuary Inundation Mapping D-16 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Mammal Miniopterus schreibersii oceanensis Eastern Bentwing-bat V,P
Caves are the primary roosting habitat, but also use derelict mines, storm-water tunnels, buildings and other man-made structures. Hunt in forested areas.
Medium
Mammal Mormopterus norfolkensis Eastern Freetail-bat V,P
Occur in dry sclerophyll forest, woodland, swamp forests and mangrove forests east of the Great Dividing Range. Medium
Mammal Myotis macropus Southern Myotis V,P
Generally roost in groups of 10 - 15 close to water in caves, mine shafts, hollow-bearing trees, storm water channels, buildings, under bridges and in dense foliage. Forage over streams and pools catching insects and small fish by raking their feet across the water surface.
Medium
Mammal Nyctophilus bifax Eastern Long-eared Bat V,P
Lowland subtropical rainforest and wet and swamp eucalypt forest, extending into adjacent moist eucalypt forest. Coastal rainforest and patches of coastal scrub are particularly favoured.
High
Mammal Orcinus orca Killer Whale migratory Ocean waters. Low
Mammal Petaurus australis Yellow-bellied Glider V,P
Inhabits tall open forest on the western fringe of the Wet Tropics Heritage Area. Floristics of the forest may vary from one location to another but the presence of two eucalypt species, Eucalyptus resinifera and Eucalyptus grandis, is essential. These occur most commonly in the wetter areas of the open eucalypt forest.
Low
Mammal Petaurus norfolcensis Squirrel Glider V,P
Inhabits mature or old growth Box, Box-Ironbark woodlands and River Red Gum forest west of the Great Dividing Range and Blackbutt-Bloodwood forest with heath understorey in coastal areas. Prefers mixed species stands with a shrub or Acacia midstorey.
Medium
Mammal Petrogale penicillata Brush-tailed Rock-wallaby V
Prefers rocky habitats, including loose boulder-piles, rocky outcrops, steep rocky slopes, cliffs, gorges and isolated rock stacks. Low
Mammal Phascogale tapoatafa Brush-tailed Phascogale V,P
Prefer dry sclerophyll open forest with sparse groundcover of herbs, grasses, shrubs or leaf litter. Also inhabit heath, swamps, rainforest and wet sclerophyll forest.
Medium
Mammal Phascolarctos cinereus Koala V,P V Inhabits eucalypt forest and woodland. High
Mammal Potorous tridactylus tridactylus Long-nosed Potoroo V
Can be found in wet eucalypt forests to coastal heaths and scrubs. Main habitat factors are dense vegetation for shelter and the presence of an abundant supply of fungi for food.
Medium
Mammal Pseudomys novaehollandiae New Holland Mouse V
Found from coastal areas and up to 100 km inland on sandstone. The species has been recorded from sea level up to around 900 m above sea level. Occurs in open heathland; open woodland with a heathland understorey and vegetated sand dunes.
Medium
Mammal Pteropus poliocephalus Grey-headed Flying-fox V,P V
Requires foraging resources and roosting sites. It is a canopy-feeding frugivore and nectarivore, which utilises vegetation communities including rainforests, open forests, closed and open woodlands, Melaleuca swamps and Banksia woodlands. It also feeds on commercial fruit crops and on introduced tree species in urban areas.
Medium
Bellingen Shire Estuary Inundation Mapping D-17 Threatened Species Records
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Family Species Common Name NSW Status
EPBC Status Preferred Habitat
Habitat Vulnerability
to SLR
Mammal Scoteanax rueppellii Greater Broad-nosed Bat V,P
Utilises a variety of habitats from woodland through to moist and dry eucalypt forest and rainforest, though it is most commonly found in tall wet forest. Usually roosts in tree hollows, it has also been found in buildings.
Medium
Mammal Sousa chinensis Indo-pacific Humpback Dolphin
marine Ocean waters. Low
Mammal Stenella attenuata Spotted Dolphin marine Ocean waters. Low
Mammal Tursiops aduncus Indian Ocean Bottlenose Dolphin marine Ocean waters. Low
Mammal Tursiops truncatus s. str. Bottlenose Dolphin marine Ocean waters. Low
Mammal Vespadelus troughtoni Eastern Cave Bat V,P
A cave-roosting species that is usually found in dry open forest and woodland, near cliffs or rocky overhangs; has been recorded roosting in disused mine workings, occasionally in colonies of up to 500 individuals. Occasionally found along cliff-lines in wet eucalypt forest and rainforest.
Low
Mammal Balaenoptera acutorostrata Minke Whale
marine Ocean Waters. Low
Mammal Balaenoptera edeni Bryde's Whale E marine Ocean Waters. Low
Mammal Balaenoptera musculus Blue Whale E marine Ocean Waters. Low
Mammal Calonectris leucomelas Streaked Shearwater migratory Ocean Waters. Low
Mammal Caperea marginata Pygmy Right Whale migratory marine
Ocean Waters. Low
Reptile Caretta caretta Loggerhead Turtle E1,P E Lays eggs on beach foredunes during summer and forages all year in marine waters.
High
Reptile Chelonia mydas Green Turtle V,P V Lays eggs on beach foredunes during summer and forages all year in marine waters. May occur in estuaries during warmer months. High
Reptile Eretmochelys imbricata Hawksbill Turtle V Beaches and ocean. High
Reptile Hoplocephalus stephensii Stephens' Banded Snake V,P
Rainforest and eucalypt forests and rocky areas up to 950 m in altitude Medium
Reptile Hydrophis elegans Elegant seasnake marine Ocean Waters. Low
Reptile Natator depressus Flatback Turtle V Ocean Waters. Low
Reptile Pelamis platurus Yellow-bellied Seasnake marine Ocean Waters. Low
Reptiles Dermochelys coriacea Leatherback Turtle V Beaches and ocean. High
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BMT WBM Newcastle 126 Belford Street, Broadmeadow 2292 PO Box 266, Broadmeadow NSW 2292 Tel +61 2 4940 8882 Fax +61 2 4940 8887 Email [email protected] Web www.bmtwbm.com.au
BMT WBM Perth Level 3, 20 Parkland Road, Osborne, WA 6017 PO Box 1027, Innaloo WA 6918 Tel +61 8 9328 2029 Fax +61 8 9486 7588 Email [email protected] Web www.bmtwbm.com.au
BMT WBM Sydney Level 1, 256-258 Norton Street, Leichhardt 2040 PO Box 194, Leichhardt NSW 2040 Tel +61 2 8987 2900 Fax +61 2 8987 2999 Email [email protected] Web www.bmtwbm.com.au
BMT WBM Vancouver Suite 401, 611 Alexander Street Vancouver British Columbia V6A 1E1 Canada Tel +1 604 683 5777 Fax +1 604 608 3232 Email [email protected] Web www.bmtwbm.com