Spatial@gov conference 2011 janet stein

Describing the stream and catchment

environment at multiple spatial scales

Janet Stein

ANU Fenner School of Environment

and Society

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ANU Fenner School of Environment and Society

Introduction• Australian Hydrological Geospatial Fabric ( “Geofabric”)

– Spatial framework for water information

– Delineates network streams and associated catchment

boundaries at a map scale of ~1:250,000

• Geofabric extension - Stream Environment Database

– 13 lookup tables

– 400+ attributes describing the natural and anthropogenic

environment of every Geofabric network stream and its

catchment

• Characterize important drivers of landscape hydrological,

geomorphological and ecological processes that in turn

influence water resource availability and condition and

ultimately control stream ecosystem patterns and

processes


Presentation Outline

1. Spatial scale of description

– Segments, sub-catchments and

catchments

2. The lookup tables and summary of

attributes

3. Examples of their application


Spatial scale of description

• Attributes describe the stream and catchment

environment at multiple spatial scales:

– Local - the stream segment +/- its valley

– Sub-catchment – catchment draining directly to the

stream segment

– Catchment - the contributing area upstream or the flow

path downstream

• Spatial units delineated at 9 second grid resolution

– about 250m


Segment scale•Segments break the stream network at tributary confluences,

waterbodies, distributary points, cliff lines and breaks in the

mapped stream network

•Segment scale attributes summarize the values of all grid

cells that comprise the stream segment (e.g. segment slope)


Segment and valley scale

Stream segment grid

cells plus cells

classified as a valley

bottom flat using the

multi-resolution

valley bottom

flatness index

(mrVBF) of Gallant

and Dowling (2003)1

1. Gallant and Dowling ( 2003) A multi-

resolution index of valley bottom flatness

for mapping depositional areas, Water

Resources Research 39(12):1347


Sub-catchment scale

• The grid cells draining

directly to the stream

segment

• Sub-catchment scale

attributes summarize the

values of all grid cells that

comprise the segment sub-

catchment


Segment

Catchment scale

Summarize (as appropriate):

• all of the grid cells upstream

of the stream segment

outlet (e.g. catchment

average rainfall)

• the grid cells downstream of

the segment outlet (e.g.

average downstream slope)


Catchment – contains all segment sub-

catchments upstream of the segment outlet

Segment

outlet

The lookup tables

• Derived using best available data sources

with national coverage

• Links to the Geofabric network streams

and catchments via shared unique

segment identifier (field

SEGMENTNO=NCB_ID)


ClimateParameters describing:

• annual, seasonal and extreme rainfall,

temperature and solar radiation

• climatic constraints on plant growth

• rainfall erosivity


Stream segment and

valley bottom

average coldest

month minimum

temperature

Catchment average coldest

month minimum temperature

Terrain• Elevation and elevation

derivatives (relief, slope,

aspect)

• Catchment area and

shape

• Network position

(Strahler stream order)

• Indicator of valley

confinement

• Distance from source /

outlet


Distance from source (catchment length)

Substrate

• Soil hydrological

characteristics

– saturated hydraulic

conductivity, available

water holding capacity,

sand and clay content

• Lithological

composition

– % area underlain by

rocks classified into

broad lithological

groupings,

unconsolidated

material, old rocks


Catchment proportion unconsolidated materialGeology data source: Geoscience Australia

Catchment water balance

• Monthly time series and

summary statistics of modelled

monthly runoff (1970-2008)

• Single bucket water balance

model - runoff accumulated

downstream along DEM derived

flow pathways

• Also statistics 30 year period

(1971-2000)

• Statistics include annual and

seasonal mean and maximum,

inter- and intra-year variability


Monthly mean accumulated runoff (GL)

Average monthly maximum

accumulated runoff (GL)

Modelled runoff with observations

from 331 gauges (Peel et al 2001)

Catchment Water Balance Summary Statistics


Vegetation cover• pre-European and extant

• % area by structural grouping

(forests, woodlands, shrubs,

grasses, bare) and by NVIS major

vegetation sub-groups


Vegetation data source:

National Vegetation Information System

pre-European

Extant

Tamar River Catchment

Forest Cover

Landuse and population

• % area by landuse

category

– 13 categories

reflecting potential

impact on water

quality and quantity

• average and

maximum

population density


Hawkesbury River Catchment

Urban Landuse

Landuse data source : BRS

River Disturbance Indices


River

Disturbance

Index (RDI)

� Indices summarise potential

impact of human activities

� Segments rated according to

the intensity and extent of

human activities:

– instream (dams, weirs,

levees, flow diversions)

and

– catchment (landuse,

point sources, logging,

settlement, infrastructure)

� Indicator of pressure

Additional tables

Connectivity

–Presence of barriers (dams, cliffs, waterfalls) up or

downstream

–Proportion of stream length that is barrier free

Stream network parameters / habitat availability

–Stream density

–Numbers and density of freshwater habitat features

(waterholes, lakes, springs, large streams mapped as a

watercourse area)

NPP (Net Primary Productivity)

–Monthly and annual mean NPP


Applications• Data supplied to a wide range of government agencies,

university researchers, consultants, NGO’s

• Assisting a variety of tasks e.g.

• Modelling freshwater biodiversity compositional turnover /

species distribution (frogs, river invertebrates, wetland plants,

mussels, fish)

• Survey design - selecting streams satisfying particular criteria

e.g. unregulated, size

• River health / condition assessment e.g. modelling reference

condition for the MDB Sustainable Rivers Audit, updating

Victorian Index of Stream Condition

• Identifying high conservation value aquatic ecosystems

Murrumbidgee River, Northern Australia

• Development of regional frameworks


Ecohydrological environment

classification


•Aim: to develop a continental scale

regional classification of Australian

rivers based on ecologically relevant

aspects of their hydrology

•Streams classified on the basis of

their similarity across a range of

landscape attributes believed to be

key drivers of the flow regime

(climate, catchment water balance,

catchment morphology, geology,

soil, vegetation)

30 group classification with

groups coloured according

to their similarity

Pusey, B. J., Kennard, M. J., Stein, J. L., Olden, J. D., Mackay, S. J., Hutchinson, M. F. and Sheldon, F. (2008) (Eds.) Ecohydrological

regionalisation of Australia: a tool for management and science. Innovations Project GRU36, Final Report to Land and Water Australia.

http://lwa.gov.au/products/pn22591

Flow characteristics of ecohydrological environment groups

• 830 gauges

on

unregulated

streams

• 120

ecologically

relevant flow

metrics


Conclusions


Stream Environment Database

•Useful extension to the Geofabric

•Data applicable to a wide range of research, monitoring,

assessment and planning tasks at regional to national scale

•setting a context for more detailed and specifically

targeted planning and assessment

•encouraging more co-ordinated management activities

•Consistent and comprehensive national coverage enables

•analysis and assessment of entire drainage basins

regardless of jurisdictional borders

•consideration of all streams large and small

Data availability


Lookup tables can be downloaded from

Geoscience Australia in ESRI file Geodatabase

format. See:

http://www.ga.gov.au/surfacewater

Acknowledgements


•The development of the stream attribute tables

was partially funded by the Northern Australia

HCVAE project undertaken for the Department of

Environment, Water, Heritage and the Arts

(Kennard et al 2010).

•Michael Stewardson and Stephen Wealands

assisted with landuse and population density

data

QUESTIONSQUESTIONS


Education

Spatial@gov conference 2011 janet stein