Overberg Municipality Road Repair Project: Basic ... Road Repairs: BERGSTAN/AppG... · Overberg Municipality Road Repair Project: Basic Assessment Report on the ... and all lie at

Main consultant Charl de Villiers Environmental Consulting

Overberg Municipality Road Repair Project:

Basic Assessment Report on the implications of repair designs for

freshwater ecosystems

Designs by Hatch Goba Engineering

March 2014

Report by Liz Day (PhD; Pr Nat Sci)

The Freshwater Consulting Group [email protected]

Basic Assessment Report on the implications of proposed road repairs in the Overberg Municipal area: Freshwater Ecosystems: Assessment of Hatch Goba Engineering designs

Freshwater Consulting Group 1

TABLE OF CONTENTS

_Toc384384596

1 Introduction ........................................................................................................................................................ 2

1.1 Background .......................................................................................................................................... 2

1.2 Terms of Reference .............................................................................................................................. 2

1.3 Study area ........................................................................................................................................... 2

1.4 Information and activities informing this report ...................................................................................... 3

1.5 Limitations of this report....................................................................................................................... 3

1.6 Definitions and terminology .................................................................................................................. 4

2 Description of proposed activities ....................................................................................................................... 5

3 Description of affected freshwater ecosystems .................................................................................................. 9

3.1 Approach ............................................................................................................................................. 9

3.1.1 NEFEPA data.................................................................................................................................................. 9 3.1.2 Present State Assessments ........................................................................................................................... 9 3.1.3 EIS Assessments ............................................................................................................................................ 9 3.1.4 Ecoregion status .......................................................................................................................................... 10

3.2 Summary descriptions of affected rivers .............................................................................................. 11

3.2.1 Water management areas .......................................................................................................................... 11 3.2.2 Ecoregions ................................................................................................................................................... 11

4 Assessment of the Implications of the proposed works for freshwater ecosystems with recommendations for

mitigation ..........................................................................................................................................................22

4.1 Impacts associated with proposed construction at OH1 (Meul River) ..................................................... 22

4.1.1 Mitigation requirements to address impacts resulting from the existing structures: ................................ 22 4.1.2 Impacts associated with layout and design ................................................................................................ 23 4.1.3 Construction phase impacts ....................................................................................................................... 24 4.1.4 Overall assessment and recommendations for OH1 (ecological perspective) ........................................... 24

4.2 Impacts associated with proposed construction at OH2 ........................................................................ 25

4.2.1 Impacts associated with layout and design ................................................................................................ 25 4.2.2 Construction phase impacts ....................................................................................................................... 25 4.2.3 Overall assessment and recommendations for OH2 (ecological perspective) ........................................... 25

4.3 Impacts associated with proposed construction at OH3 (Jagersbosch River) ........................................... 25

4.3.1 Mitigation requirements to address impacts resulting from the existing structures: ................................ 25 4.3.2 Impacts associated with layout and design ................................................................................................ 25 4.3.3 Construction phase impacts ....................................................................................................................... 25 4.3.4 Overall assessment and recommendation for OH3 (ecological perspective) ............................................. 26

4.4 Impacts associated with proposed construction at OH4 (Droogas River) ................................................. 26

4.4.1 Impacts associated with Layout and design ............................................................................................... 26 4.4.2 Construction phase impacts ....................................................................................................................... 26 4.4.3 Overall assessment and recommendation for OH4 (ecological perspective) ............................................. 27

4.5 Overall implications of proposed construction activities for watercourse PES.......................................... 28

5 Construction phase management recommendaTIONS .......................................................................................29

6 National Water Act compliance considerations .................................................................................................31

7 Conclusions ........................................................................................................................................................32

8 References .........................................................................................................................................................33

Appendices ................................................................................................................................................................34



1 INTRODUCTION

1.1 Background

Following extensive flood damage in parts of the Overberg District in recent years, including late 2013, the

Department of Transport and Public Works (DTPW) in the Western Cape proposes to undertake road

and/or bridge repairs and/or upgrades at a number of watercourse crossings. A number of the proposed

activities include triggers for a Basic Assessment in terms of the provisions of the National Environment

Management Act (NEMA) (Act 107 of 1998), and as such require authorization from the Department of

Environmental Affairs and Development Planning (DEADP). Charl de Villiers was appointed by the

Department of Transport in the Western Cape as the Environmental Assessment Practitioner (EAP) to

oversee the Basic Assessment application process. Since the proposed activities affected potentially

watercourses and/or wetlands, Freshwater Consulting cc (t/a The Freshwater Consulting Group / FCG) was

in turn appointed to provide specialist input into the Basic Assessment process, including input into

measures to mitigate against existing and likely impacts to freshwater ecosystems.

While the DTPW is currently engaged in applications for several repairs / upgrades to its roads and bridges

in the Overberg area, this report addresses only those currently being designed by Hatch Goba Engineers.

A total of four structures have been addressed in this report.

1.2 Terms of Reference

FCG’s terms of reference for this project allowed for:

• A desktop study of four proposed sites, including assessment of NFEPA and other relevant spatial

conservation planning data for the affected watercourses, and an assessment of historical GOOGLE

imagery of each site;

• A desktop assessment of the proposed repair / construction activities;

• A site visit for visual assessments of the existing watercourses and structures;

• Liaison with the project engineer regarding the proposed activities, with particular regard to the

planning of mitigation approaches;

• Compilation of a Basic Assessment Report, outlining the following:

o Descriptions of the watercourse at the affected sites;

o Descriptions of the conservation status of each affected watercourse in the vicinity of the

sites, including reference to NFEPA and other information, and comment on its accuracy;

o Level 1 Assessment of the Present Ecological State (PES) of the watercourse in the affected

reach;

o Assessment of the Ecological Importance and Sensitivity (EIS) of the watercourse in the

affected reach;

o Comment on the likely impact of the proposed construction with and without mitigation on

PES and EIS;

o Recommended mitigation measures for each site;

• Compilation of ecological Best Practice recommendations to include in the construction phase

management plans for each site.

1.3 Study area

Figure 1.1 shows the locations of the four sites (OH1 - OH4) included in the present assessment. They are

all located in the Riviersonderend catchment, and all lie at watercourse crossings on minor gravel roads,

with OH1 and OH2 being on District Road (DR) 1298, OH3 on DR1303 and OH4 on DR1310.



Figure 1.1

Locations of proposed road repair / upgrade sites addressed in this project, showing site codes (OH1 etc.) and name

(if any) of the affected watercourse Figure courtesy Mr C. de Villiers (Project EAP)

1.4 Information and activities informing this report

The inputs provided in this report have been informed by:

• A meeting with the project engineer (Mr Dawie Malan, Hatch Goba) to discuss the proposed project

approach and various mitigation measures;

• A site visit to all of the sites included in this assessment, accompanied by Mr Charl de Villiers (project

EAP) – existing PES data for the affected rivers was ground-truthed during the site visits and EIS ratings

were carried out at each site, using the methodology outlined in Appendix A;

• Consultation of existing spatial data pertaining to the study area (NEFEPA datasets and present and

historical GOOGLE satellite imagery);

• Discussions with Mr Hans King (engineer; Department of Agriculture in the Western Cape) regarding

proposed groyne field designs in the Meul River.

1.5 Limitations of this report

No new biophysical or water quality data were collected as part of this report, which relied primarily on a

visual assessment of issues of ecological concern and existing Conservation Planning data (e.g. NEFEPA

datasets). In particular, no floral or faunal analysis or ground-truthing was carried out. Given the extent to

which the affected sites have been disturbed, these are not considered significant limitations.

Site OH2 was not included in the site visits, as it was added to the project list only latterly. Input into the

assessment of the structure at this site was based on photographs provided to Charl De Villiers (project

EAP) by Mr D. Malan.



1.6 Definitions and terminology

The definitions for watercourses and wetlands that have been used by FCG in this project are those

specified by the National Water Act (Act 36 of 1998), which defines a “watercourse” as:

(a) a river or spring;

(b) a natural channel in which water flows regularly or intermittently;

(c) a wetland, lake or dam into which, or from which, water flows; and

(d) any collection of water which the Minister may, by notice in the Gazette, declare to be watercourse, and

a reference to a watercourse includes, where relevant, its bed and banks.

Wetlands themselves are defined in the Act as:

“land which is transitional between terrestrial and aquatic systems where the water table is usually at or

near the surface, or the land is periodically covered with shallow water, and which land in normal

circumstances supports or would support vegetation typically adapted to life in saturated soil.”



2 DESCRIPTION OF PROPOSED ACTIVITIES

Table 2.1 provides a summary of the activities proposed at each of the four affected sites. Figures 2.1 – 2.4

comprise annotated GOOGLE imagery for each site, showing the positions of each new / upgraded

structure as well as any proposed road re-alignments and/or temporary bypass roads.

Figure 2.1

GOOGLE Satellite image showing location of proposed crossing upgrades / repairs at OH1.

Figure courtesy Charl de Villiers (project EAP). Direction of flow arrowed.

Figure 2.2





Figure 2.2

Figure 2.3



Figure 2.4





Table 2.1

Description of activities proposed for each of the four affected watercourse crossings

Table courtesy Charl De Villiers (project EAP).

Project Route km Structure Co-ordinates 1:50 000

sheet Current condition of structures Proposed repairs

By-

pass

Environmental

factors

contributing to

damage

OH1 DR1298 17.87 0550 34° 3'34.98"S

19°28'38.64"E

34191AB Damaged bridge over Meul River. Large

crack at SE junction of wing wall and

abutment. Portion of NE wing wall has

collapsed. Guide blocks loose due to

impact damage – apparently from

farming implements – due to inadequate

width of deck slab. Severe wash aways of

eastern approach (late 1990s, 2007 and

2012). Inadequate hydraulic capacity.

Replace existing structure with a

new in-situ concrete causeway

with sufficient hydraulic capacity,

consisting of four 5 m-long spans

with wing walls and apron slabs

upstream and downstream.

Yes

Channel

upstream

devoid of

wetland/riparian

vegetation;

intensively

bulldozed;

berms.

OH2 DR1298 18.7 34° 3'26.52"S

19°29'9.06"E

3419AB Two x 900 mm diameter pipes venting

pipe culvert crossing over unnamed

watercourse 800m E of Meul River.

Erosion of embankment at inlet, caused

by run-off from the road. Masonry

headwall in a poor state of repairs.

New in-situ concrete inlet and

outlet structures.

No

Road run-off

contributes to

localised

erosion.

OH3 DR1298 20.88 0552 34° 3'10.92"S

19°30'30.96"E

3419BA Single reinforced concrete culvert at

Jagersbosch River with significant skew

angle. Structure in good condition.

Alignment of river (apparently to create

extra farm land) causes severe erosion of

embankment approach to inlet. Signs of

minor soft water attack and minor

shrinkage cracks evident.

Provide wing walls at inlet side of

culvert to channel water into the

inlet and to protect the

approaches against erosion.

No

Watercourse

upstream

approaches

culvert at acute

angle from fields

to NE. Deeply

incised. Elevated

nick-point

several meters

upstream:

Potential head-

cut erosion? Left

bank collapsing

at bridge

support.



OH4 DR1310 2.54 10704 34° 8'15.24"S

19°43'25.08"E

-34.137567°

19.723633°

3419BA Single cell box culvert in Droogas River

with a simply supported deck on concrete

walls and spread footings. Wing walls

have been provided. Deck has severe

local spalling on both sides. NE wing wall

has failed, resulting in damage to

abutment. Similar but less severe failure

to SW wing wall. No evidence of over-

topping suggesting adequate hydraulic

capacity. Cause of wing fall failure seems

to be inadequate footing, exacerbated by

absence of weep holes.

Replace NE wing wall of culvert

and repair junction of wing wall

to abutment.

Yes

Cultivated

catchment to

south seems to

release

substantial

volumes of

uncontrolled

run-off owing to

absence of

indigenous

vegetation

cover. No

vegetated buffer

between

watercourse and

fields.



3 DESCRIPTION OF AFFECTED FRESHWATER ECOSYSTEMS

3.1 Approach

The summary descriptions outlined in this section for each site rely on the following data / assessment

tools, described briefly below:

3.1.1 NEFEPA data

FEPAs (Freshwater Ecosystem Priority Areas) are strategic priorities for conserving freshwater ecosystems

and supporting the sustainable use of water resources (Driver et al 2011). They were developed as part of

the National Freshwater Ecosystem Priority Areas (NFEPA) programme. FEPAs have been determined for

different river and wetland types throughout South Africa, on the basis of a number of criteria that included

ensuring that there is an adequate extent of conservation of different river and wetland ecosystem types,

that they represent adequate habitats to support threatened fish species and their migration corridors;

that free-flowing rivers (i.e. rivers without major dams) are prioritised as FEPAs, that water supply areas in

high-water yielding sub-quaternary catchments are maintained and that ecological connectivity between

systems is maintained as far as possible.

• FEPAs are often tributaries or rivers that support “hard working” rivers downstream (that is, rivers that

are heavily utilised or impacted by agricultural, industrial or other human activities). They need to stay

(or get into) good condition to manage and conserve freshwater ecosystems and to protect

downstream water resources for human use. Driver et al (2011) stress however that FEPAs do not

necessarily need to be protected from all human use. Rather, they should be supported by good

planning, decision-making and management to ensure that human use does not impact on their

condition or on the important resources they may protect downstream.

• The extent of degradation of wetlands and rivers in South Africa means that even systems considered

in the best relative condition for a particular ecosystem type may be highly degraded. Nevertheless,

the recommended condition for all river and wetland FEPAs is an Ecological Category A or B, indicative

of a system that is in an unmodified/natural to largely natural condition respectively (Driver et al 2011).

3.1.2 Present State Assessments

Present State assessments are included in the NEFEPA datasets for both rivers and wetlands. In the case of

the larger rivers, shown on the 1:500 000 these data were derived either from Kleynhans (2000), who used

the DWAF (1999) Present Ecological State (PES) methodology to determine PES for quaternary catchment

mainstem rivers or for smaller tributaries and rivers, were modelled, using the 2000 National Land Cover

(Nel et al. 2011) to allow a surrogate estimate for river condition, based on the extent of natural,

transformed or eroded land within 100m and 500m of the river course. These data were then revised on

the basis, where available, of more detailed data and/or expert opinion. Given that river and wetland

“condition” data may thus be coarse, as well as the fact that the spatial data on which they are based are

over a decade old, detailed notes collected at each assessment site were used to refine the PES category,

where appropriate. Motivation for such changes is provided in Section 3.3.

3.1.3 EIS Assessments

This report utilised the Ecological Importance and Sensitivity (EIS) methodology developed by DWAF (1999)

to derive EIS ratings for the watercourses at each assessed site (OB1-OB6). DWAF (1999) defines the

ecological importance of a river as an expression of its importance to the maintenance of ecological

diversity and functioning on local and wider scales, while ecological sensitivity (or fragility) refers to the

system’s ability to resist disturbance and its capability to recover from disturbance once it has occurred

(resilience). Both abiotic and biotic components of the system are taken into consideration in the

assessment of ecological importance and sensitivity. Importantly, it should be noted that EIS ratings are

strongly biased towards the potential importance and sensitivity of particular system as it would expected

to be under unimpaired conditions. This means that the present ecological status or condition (PES) is

generally not considered in determining the ecological importance and sensitivity per se (DWAF 1999). The

following components are considered in an EIS assessment, namely:



• The presence of rare and endangered species, unique species (i.e. endemic or isolated populations) and

communities, intolerant species and species diversity should be taken into account for both the

instream and riparian components of the river.

• Habitat diversity

• biodiversity in its general form

• The importance of the particular river or stretch of river in providing connectivity between different

sections of the river

• The presence of conservation or relatively natural areas along the river section

• The sensitivity (or fragility) of the system and its resilience (i.e. the ability to recover following

disturbance) of the system to environmental changes.

• The above biotic and abiotic determinants are scored, and the median score is calculated to derive the

ecological importance and sensitivity category. These categories are defined in Table 3.1.

Note that in the present case, the biotic component of the assessment was not however completed, due to

a lack of data for these systems. It is however unlikely that inclusion of the biotic component would have

altered the final EIS score for the watercourses at each site, given that it is the higher of the EIS categories

that is utilised, and the biotic components for all sites is unlikely to be accorded a higher rating than

“moderate” for any of the affected systems. This assumption is based on river condition and the NEFEPA

datasets.

Table 3.1 Ecological importance and sensitivity categories (Table after DWAF 1999).

Ecological

Importance And

Sensitivity

Categories

General Description

Very high

Quaternaries/delineations that are considered to be unique on a national or

even international level based on unique biodiversity (habitat diversity,

species diversity, unique species, rare and endangered species). These rivers

(in terms of biota and habitat) are usually very sensitive to flow

modifications and have no or only a small capacity for use.

High

Quaternaries/delineations that are considered to be unique on a national

scale due to biodiversity (habitat diversity, species diversity, unique species,

rare and endangered species). These rivers (in terms of biota and habitat)

may be sensitive to flow modifications but in some cases, may have a

substantial capacity for use.

Moderate

Quaternaries/delineations that are considered to be unique on a provincial

or local scale due to biodiversity (habitat diversity, species diversity, unique

species, rare and endangered species). These rivers (in terms of biota and

habitat) are usually not very sensitive to flow modifications and often have a

substantial capacity for use.

Low/marginal

Quaternaries/delineations that are not unique at any scale. These rivers (in

terms of biota and habitat) are generally not very sensitive to flow

modifications and usually have a substantial capacity for use.

3.1.4 Ecoregion status

The national ecoregional classification (Kleynhans et al. 2005) was used as a broad mechanism to categorise

watercourses at each site. This classification system divides the country’s rivers into 31 distinct ecoregions,

or groups of rivers which share similar physiography, climate, geology, soils and potential natural

vegetation.



3.2 Summary descriptions of affected rivers

Figures 3.1 and 3.2 and Table 3.2 provides summary information regarding the ecological condition,

importance and sensitivity and catchment characteristics as included in the NEFEPA datasets for the water

courses in the vicinity of the structures proposed for upgrading / repair. Ecological condition (i.e. PES) data

reflect both NEFEPA data, and the results of ground truthing, carried out at the site during the field

assessments.

Summary descriptions of the main ecological issues affecting habitat integrity in each of the watercourses

at the crossing points is presented in table form in Table 3.3, which includes photographic illustrations of

each site. The following subsections provide brief information regarding broad spatial and ecological

features, and comments on PES and EIS.

3.2.1 Water management areas

All of the affected sites lie within the Department of Water Affairs’ Breede Water Management Area (WMA

19). Each WMA has been divided into several smaller sub-Water Management Areas, based on the

catchments of large tributaries within the WMA. In this regard, the NEFEPA data (Nel et al 2011) show that

all four of the assessed sites lie in sub Water Management Area 33 (Riviersonderend). Table 3.2 and

Figures 3.1 and 3.2 illustrate which of these sub WMAs have been categorized as FEPA sub-quaternary

catchments, on the basis of particular criteria included in the NEFEPA conservation planning process (Nel et

al 2011).

3.2.2 Ecoregions

Consideration of the Kleynhans et al (2005) Level 1 Ecoregion spatial data, as included in the NEFEPA River

datasets, shows that all four sites lie in Ecoregion 22. This ecoregion (the Southern Coastal Belt Ecoregion)

is described in Kleynhans et al (2005) as encompassing the rivers in the southern portion of the Breede

River Basin (Brown and Fowler 2000), and is characterised by the following, after Brown and Fowler (2000):

• Terrain comprising low plains, closed hills with moderate relief, open hills with high relief, and low

mountains with high relief;

• Altitude that varies from 0 to 600 mamsl;

• Rock types include quartzitic sandstone, shale, sand and biotite granite overlain by sand-clay, sand-clay-

loam, loam-sand, clay-loam and sand-loam soils;

• Natural terrestrial vegetation that is dominated by a variety of thicket, fynbos and renosterveld, with

patches of forest in the Riversonderend range. In the present study area, NEFEPA vegetation data,

based on the South African Vegetation Map (Mucina and Rutherford 2006) identifies natural wetland

vegetation on the site as Southwest Shale Fynbos;

• Moderate rainfall (400 to > 1200 mm a-1) and mean annual temperatures between 18 and 22 °C.



Table 3.2 Descriptions of watercourse condition in the vicinity of each of the proposed structural upgrades, including both ground-truthed PES and EIS

ratings and NEFEPA data.

Site

code River

Brief description

based on site visit

(see also Table 3.2)

Water course condition (PES)

EIS

(see data

in

Appendix

A)

National Freshwater Ecosystem Priority Area (NFEPA) status

NFEPA

Wetlan

d

PES

Ground-truthed PES (as

assessed during site

visit)

River FEPA

or

associated

Sub-

quaternary

catchment?

Wetland

FEPA ?

FEPA

attributes

Wetland

type

(NWCS (Ollis

et al 2013)

Levels 3 and

4)

Wetland

Vegetation

Group

OH1 Meul Rv

River severely

degraded and prone

to high levels of

ongoing channel

destabilisation – no

associated wetland

habitat

Class C

Class E: erosion,

sedimentation, loss of

almost all indigenous

instream vegetation and

habitat and all riparian

vegetation; severe alien

invasion

Low /

Marginal

No No

CRANE (i.e.

wetlands in

sub-

quaternary

catchments

with

sightings of

threatened

crane

species (Nel

at al 2013);

also

associated

with more

than three

other

wetlands

East Coast

Shale

Renostervel

d Floodplain

wetland: no

wetland

identified in

this study East coast

shale

renosterveld

OH2

Un-named

tributary of

the Rivier-

sonderend,

just east of

Meul Rv

Narrow channel, with

high levels of

agricultural

encroachment,

abstraction (dams)

and channelization

Class C

Class D – low confidence

assessment based on

photographs and

GOOGLE imagery only:

channelization, woody

alien invasion along

channel; abstraction;

poor habitat quality; low

levels of buffering; poor

connectivity to mountain

areas upslope

Low /

Marginal

Phase 2

FEPA No

OH3 Jagersbosc

h Rv

River degraded – but

morphology

upstream still

representative of

natural valley bottom

wetland type

Class C

Class D: high levels of

disturbance adjacent to

the stream upstream of

structure; large-scale

loss of indigenous

riparian and instream

vegetation; natural

upstream morphology

still recognisable;

Moderate

Phase 2

FEPA No



Site

code River

Brief description

based on site visit

(see also Table 3.2)

Water course condition (PES)

EIS

(see data

in

Appendix

A)

National Freshwater Ecosystem Priority Area (NFEPA) status

NFEPA

Wetlan

d

PES

Ground-truthed PES (as

assessed during site

visit)

River FEPA

or

associated

Sub-

quaternary

catchment?

Wetland

FEPA ?

FEPA

attributes

Wetland

type

(NWCS (Ollis

et al 2013)

Levels 3 and

4)

Wetland

Vegetation

Group

OH4 Droogas Rv

River degraded – but

still retains relatively

natural instream

(valley bottom

wetland) habitat;

little erosion or

sedimentation

evident

Class C

Class C /D – nutrient-

enriched, with minimal

buffers; cattle grazed

and trampled but still

morphologically

relatively intact

Moderate

Phase 2

FEPA No



Table 3.3 Site level descriptions and photographic illustrations of ecological issues affecting the current state of the watercourses at each crossing

A. Site OH1 – Meul River

NWCS river classification: Lower foothill river

NWCS wetland classification: channeled valley bottom wetland

Description of the river at the site Main drivers of ecological degradation Main concerns regarding ecological effects of present

road / bridge structure

The river channel is highly disturbed, with little or no

instream vegetation, and the instream habitat comprising

shallow pools and riffles occurs on a loose matrix of

gravel, sand and rocks with high levels of instability in

high flow.

The right hand river bank downstream of the bridge

retains largely indigenous marginal vegetation.

Elsewhere, the banks have been bulldozed, bermed or

eroded and comprise loose, bare gravels and sand.

A working hypothesis to explain the evident channel

destabilisation assumes that it results from combined

effects of historical intrusion of agricultural activities

into the floodplain, and extensive alien invasion of the

river channel, resulting in constriction of the channel in

flood flows (see 2009 aerial views below) and breaking

out of channel in the upper cactchment, to erode

vulnerable agricultural areas, as far as line of windbreak

beefwood trees, which further constricted flows,

sending them back into the channel, with high

sediment and rock load, and devastating downstream

effects. Subsequent floods (see 2012 close-up)

assumed to have scoured the now destabilized

channel, devoid of both alien and natural wetland

vegetation. Retention of beefwoods downstream of

OH-1facilitates catastrophic creation of new side-

channels (Photo OH1-D) by constricting overtopping

onto floodplain, resulting in severe in-channel

disturbance and large-scale outbreaks in large flood

events.

• Bridge now too narrow for new flow and flood

regime, with high load of sediment and rocks

• Overtopping of bridge at OH-1 leading to further

erosion downstream, including diversion of high

flows into eastern floodplain areas



Photo OH1-A

Meul River downstream from the bridge at OH1, showing line of

beefwoods along right hand banks and severe channel

destabilisation

Photo OH1-B

Meul River upstream of bridge showing severe loss of natural

instream habitat (assumed to comprise channelled valley

bottom wetland)

Photo OH1-C

View from upstream onto damaged bridge at OH1, showing

narrow structure blocked by high sediment / cobble loads

Photo OH1-D

View immediately east of Photo H1-A, showing erosion path

onto agriculural floodplain beyond beefwoood line, resulting in

severe erosion



Sequence of aerial photogrpahs of the Meul River

Meul River in 2004 (arrowed) showing vegetated channel; high levels of alien invasion with

remnant wetland patches:

2006 view of Meul River showing dense invasion of channel

2009: large-scale erosion of the whole length of the Meul River. Area included in following

sequence of “close-ups” circled

2004 close-up showing agricultural encroachment into the floodplain in upper river reaches, with

lines of (assumed) windbreak alien trees (beefwood?) (arrowed)



2009 close-up showing breakthrough of flood flows along invaded side channel (arrowed), and

erosion of agricultural fields along the windbreak line

2012close-up showing ongoing destabilisation of the main channel, and less erosion of the

abutting floodplain, once alien vegetation had been eroded (or otherwise removed) from the

main channel

B Site OH2 – Unnamed tributary of the Riviersonderend



Description Main drivers of ecological degradation Main concerns regarding ecological effects of present


Despite its classification as within a Phase 2 FEPA sub-catchment

(see Table 3.2), the channel at OH2 is considered of ecological

importance today only in terms of stable conveyance of flows

through its catchment; in NEFEPA terms, it is a “hard-working”

system, with high levels of upstream abstraction and no wetland

areas visible from GOOGLE aerial photography. Rehabilitation to

a better PES class is not considered realistic, although it would

be possible. At the existing culvert, the channel is shaded by

alien trees, which further reduce indigenous vegetation and

habitat quality.

• Channelisation

• Large-scale abstraction of a small catchment

• Lack of ecological connectivity with upstream areas

and downstream Riviersonderend as a result of

agriculture; minimal buffer areas

• Culverts contribute to channelization of stream – but

small stream considered of low ecological importance

given extent of degradation; channel appears

currently stable at road crossing

• Localized effects of erosion off road into channel

Note: All photographs below supplied by Hatch Goba engineers. Site unvisited by FCG



Photo OH2-A

Narrow, channelised stream at OH2, showing shading of the

channel by alien vegetation.

Photo OH2-B

View of culvert from the road – left hand side culvert is

upstream

Photo OH2-C

Channelised culvert

2012 GOOGLE image showing unnamed system at OH2 in higly agriculural aea, with low

ecological connectivity

C Site OH3 – Jagersboschrivier







Relatively small river system, confined by alien trees on

right hand bank and agricultural fields on left hand banks

but not deeply incised until it approaches culvert. A small

headcut has formed just upstream of the culvert, and is

likely to result in ongoing channel incision in upstream

reaches and progressive river degradation.

Instream habitat quality at the culvert is low, comprising

cobble / gravel riffles, shallow pools and sand bars, the

latter occurring on the right hand part of the channel

where sedimentation occurs. Shading by alien trees and

steep, eroding banks limit the extent of indigenous

marginal vegetation.

• Alien invasion

• Headcut erosion

• Lack of ecological buffering

• Localized constriction at the road

• Loss of indigenous wetland and riverine vegetation.

Despite the above, the river is considered rehabilitable to

a better PES, through alien clearing and establishment of

indigenous vegetation in the upstream reaches, provided

that the headcut is addressed.

The angle of the culvert results in ongoing erosion of the

river bank (Photo OH3-C), and the associated turbulence

when large flows hit this bank and are diverted into the

culvert are assumed to have led to the formation of the

headcut visible in Photo OH3-B.

Photo OH3-A

Upstream view of culvert and stream at OH3

Photo OH3-B

Headcut (arrowed) at OH3, with fill platform on left of photo

Photo OH3-C

Eroding left hand bank to be stabilised byproposed works

D Site OH4 – Droogas Rivier





River primarily affected by poor water quality (nutrient

enrichment); retains relatively natural (assumed)

morphological features of a channeled valley bottom

wetland, despite extensive agricultural development.

• poor water quality (nutrient enrichment);

• grazing and trampling by cattle

• agricultural encroachment

• invasion of margins by kikuyu grass

Existing structure appears adequate for river / wetland

type and characteristics, with stable valley bottom

wetland upstream providing erosion control in flooding,

and floods overtopping road relatively harmlessly (from



an ecological perspective) without resulting in large-scale

erosion. Concentration of flows through culvert may

have resulted in some channel deepening downstream,

shown by reduced width of reedbed fringe across river.

Photo OH4-A

Damaged culvert at OH4, looking upstream at bridge from right

hand bank

Photo OH4-B

Downstream view of Droogas channel from road culvert at OH4

Photo OH4-C

Upstream view of Droogas channel from road culvert at OH4.

Note algae in channel (showing probable nutrient enrichment)

and dense reedbed in shallow upstream reaches


Freshwater Consulting Group 21Figure 3.2 Site OH4 in the Riviersonderend River catchment, shown in relation to FEPA data, with green polygons illustrating FEPA wetlands, thick blue lines showing FEPA

rivers (i.e. rivers included in the National 1:50 000 rivers database) and purple polygons depicting River FEPA sub-quaternary catchments, labelled in terms of

FEPA River status (if any). Note that OH4 lies within a Phase 2 FEPA catchment.



4 ASSESSMENT OF THE IMPLICATIONS OF THE PROPOSED WORKS FOR FRESHWATER ECOSYSTEMS WITH RECOMMENDATIONS FOR MITIGATION

This section identifies concerns regarding the potential impacts of proposed road repair and upgrading

activities, from a freshwater perspective. The assessed activities are as described in Section 2. These are

assessed in light of the ecological information provided in Section 3, particularly in Table 3.3, which sought

to identify key ecological concerns in the present state of the affected systems, and to highlight particular

areas of sensitivity.

Mitigation measures are also outlined in this section. These have been developed as far as possible in

consultation with the design engineers (Hatch Goba), and seek to achieve as far as possible either impact

avoidance or minimization. Note that where mitigation measures require implementation of generic “Best

Practice” measures during construction phases, these are as outlined in Section 5. In some cases however,

mitigation measures have been recommended to address the high levels of impact to aquatic ecosystems

that have accrued as a result of the existing structures, bearing in mind that these impacts are often

compounded by poor landuse practices – in particular, the failure by local landowners to control or

properly remove, invasive alien vegetation along water courses

4.1 Impacts associated with proposed construction at OH1 (Meul River)

4.1.1 Mitigation requirements to address impacts resulting from the existing structures:

The existing structure contributed to the extent of flood damage in downstream areas, and in particular to

the erosion of the floodplain on the left hand side of the channel (Table 3.3; Photo OH1-C). The existing

structure was too narrow and its culvert sizes too small to allow for the high levels of sediment and rock

generated by the destabilised, eroding river system upstream. This said, the destabilisation of the

upstream reaches of the river is believed to have resulted primarily from an unfortunate combination of

floodplain encroachment and stabilisation with rows of (alien) trees, invasion of the river channel by alien

vegetation and subsequent large-scale flood events (initially around 2009) (see Table 3.3). Full blame for

the destabilisation of the downstream reaches of the river cannot be apportioned to the existing culvert,

although it seems reasonable to allot some responsibility to this road structure.

In order to redress this effect, at least in part, and bearing in mind that such activities would render the

new proposed structure more sustainable in the future, it is recommended that the following activities be

included in the road construction programme:

i. The DTPW should liaise with the Department of Agriculture (DA) regarding the proposed

installation of a groyne field in the Meul River, and ensure that bank erosion and channel migration

in the reaches at least 50m upstream and downstream of the crossing are controlled by groynes,

designed in keeping with the objectives of the broader DA flood and erosion control programme.

Such structures ideally need to be in place before the start of the present proposed activities – in

the event that delays in their authorization through DA are considered likely, it is recommended

that the DTPW either work with DA to prioritise approval and construction of the structures that

would affect the present road, or design and obtain authorization for such structures separately. It

is noted in this regard that the proposed design at OH1 already assumes implementation of the

groyne field, and allows for a lower invert level in the crossing than that required at present, given

that the river would be downcut by concentration of flood flows;

ii. The existing berms upstream of the culvert should be pulled back and graded at an angle no

steeper than 1:4 for at least a distance of 30m upstream of the proposed new structure – note that

these activities would need to take cognisance of the location and design of the groynes, outlined

above;

iii. The regraded banks should be planted with locally indigenous hardy vegetation that has the

principle function of ensuring bank stability; the hardy Carpobrotus sp. (suurvygie) could be

considered in this regard, although its contribution to desirable ecological functions such as the

provision of quality river marginal vegetation habitat is very low;



iv. Allowance should be made for irrigation and other maintenance activities in planted areas over at

least one full year cycle;

v. Excess material from the graded river banks, as well as deposited material from the channel should

be spread in the eroded floodplain, with the aim of controlling the ongoing passage of river flows

into this area, outside of major flood flows;

vi. The line of alien trees along the left hand river bank downstream of the bridge should be removed,

using species-appropriate alien clearing methods – Working for Water guidelines should be used in

this regard. The full line of alien vegetation shown in Figure 4.1 (mainly Beefwood (Casuarina

cunninghamiana)) should be removed – it is recommended that the DTPW liaise with the local

landowner in this regard;

vii. Cleared areas should be stabilised by a combination (as appropriate) of bank shaping and planting

with locally indigenous plant species;

viii. Local landowners should be required to participate in long-term alien maintenance clearing

activities.

4.1.2 Impacts associated with layout and design

A Positive aspects

• The proposed new structure would be wider than the current one, and extend across a channel width

of some 20m, including (on the basis of a GOOGLE channel width measurement) the full current width

of the enlarged channel. This, coupled with the greater culvert size (each one would have a 5m wide

opening) would decrease flood-related erosion and sedimentation risks in the vicinity of the road, as

large sediment /debris should be able to pass through the structure unhindered.

• If the proposed road and culvert rehabilitation activities were coupled with the mitigation measures

outlined in Section 4.1.1, particularly with regard to the planned installation of groynes along this

section of the river, then it is likely that a better quality of riverine habitat, albeit not one resembling

the natural Reference Condition for this wetland type, would be established at least in the vicinity of

the road. In the absence of such measures, it is unlikely that the river will ever achieve a level of

stability that is not succeeded by its disturbance regime, which prevents the establishment of any

quality riverine or wetland habitat in these reaches.

B Negative Impacts

• Ongoing erosion of the destabilised river channel and its margins, as a result of lack of adequate plant

cover;

• In the event that existing concrete and other waste associated with the present channel is not

removed, its persistence in the channel would constitute an ongoing potential trigger for erosion as a

result of diversion of flows off the hard structure, as well as being visually displeasing.

Mitigation requirements:

i. Allowance must be made for the establishment of a continuous swathe of appropriate, locally

indigenous vegetation along at least the wetted bottom of the bank of the river, but ideally up the

bank as well, for a distance of 30m up- and downstream of the proposed structure, to prevent

erosion. It is strongly recommended that dense stands of Palmiet reeds (Prionium serratum)

should be utilised for this purpose. Other plant species used should be selected in consultation

with a botanist and/or river ecologist, to ensure they meet the required criteria of being hardy,

locally indigenous and suited to the conditions in which they are planted;

ii. All concrete and other debris associated with the present road crossing should be removed from

the river bed and banks as soon as the requirement for a construction-phase bypass road is over,

and disposed of outside of the 1:50 year flood line for the river;

iii. Planted areas should be subjected to a short-term maintenance programme that includes where

necessary, weeding, plant replacement and irrigation, over at least one full annual cycle.



4.1.3 Construction phase impacts

Construction phase impacts are likely to be of high intensity but locally confined, and readily managed

through implementation of standard impact mitigation measures. Impacts are likely to include:

• Diversion of river flows and further destabilisation of river banks as a result of construction of a

temporary bypass road;

• Increased downstream sediment and turbidity from bank and bed disturbance (the river is however

already prone to these effects as a result of high erosion);

• Contamination of the river as a result of receipt of construction-associated materials;

• Trampling and disturbance to the (already disturbed) river bed and banks in the vicinity of the existing

and new structures.

The above impacts would all be exacerbated if construction took place during the wet season when the

water table was high, or during a period when a storm event occurred.

Mitigation requirements

A Construction Phase Environmental Management Programme (CEMP) must be implemented during

construction, such that specifically addresses the need for reduction of construction-associated impacts on

watercourses, including the measures outlined in Section 5.

Special attention should be paid to management of the diversion of flows and the placement and removal

of the bypass road during construction. While the extent of riverine disturbance in these reaches suggests

that a bypass could be located on either side of the existing structure, rehabilitation and management of a

bypass road would be more readily achieved if the bypass was located on the upstream side of the

structure, as the right hand river margins downstream of the bridge still include wetland and riverine

habitat, while the upstream channel is narrower and the channel margins are already steep, bermed and

degraded. Mitigation measures affecting the bypass road should include the following:

i. Construction activities involving the use of a bypass road should at least take place outside of the

rainy season, to reduce the risk of flooding and wash-away of the bypass, although it is recognized

that summer storms do occur in this area, and result in considerable flood damage;

ii. The bypass road should allow for the passage of flows beneath the road, whether in pipes or other

devices,

iii. The bypass road should be completely removed following construction, and its footprint

rehabilitated, allowing for:

a. regrading of the river bank to a river ecologist’s specifications

b. replanting of the disturbed river bank – using the specifications for planting and short-term

maintenance outlined in Section 4.1.2B

c. removal of all foreign material from the river bed and banks (pipes etc.).

4.1.4 Overall assessment and recommendations for OH1 (ecological perspective)

Implementation of the proposed structure at OH1 would, in the absence of any mitigation measures aimed

at stabilizing the high rates of erosion and sedimentation taking place upstream in the Meul River be likely

to perpetuate an unstable system.

Implementation of the proposed mitigation measures, along with the planned improved road structure,

would be considered a positive impact, of low to medium significance, nevertheless associated with high

levels of risk that degradation has proceeded too far for real rehabilitation to be feasible.



4.2 Impacts associated with proposed construction at OH2

4.2.1 Impacts associated with Layout and design

A Positive impacts

The proposed repairs to the existing culvert headwalls would be expected to have low levels of positive

impact on the affected watercourse, at a very local scale, by reducing the volumes of eroded sediment

entering the channel off the road.


Such impacts would include short-term disturbance of the channel in the vicinity of the headwalls, the

potential passage of dewatered material into the watercourse and contamination of the watercourse by

construction associated materials such as cement. Such impacts would be considered negative, but

localised, taking place at low magnitude and over a short period of time only.

The above impacts would however be exacerbated if construction took place during the wet season when

the water table was high, or during a period when a storm event occurred.


The requirements of a comprehensive CEMP must be met during construction (see Section 5). In addition,

it is recommended that the woody alien trees shown in Table 3.3 (Photograph OH2-A) should be removed

for a distance of 20m upstream of the culvert, and the length of channel; thus exposed should, where

necessary, be stabilized with the planting of appropriate locally indigenous plant species.

4.2.3 Overall assessment and recommendation for OH2 (ecological perspective)

The ecological implications of the proposed activities at OH2 are considered negligible, assuming

implementation of mitigation measures.

4.3 Impacts associated with proposed construction at OH3 (Jagersbosch River)

4.3.1 Mitigation requirements to address impacts resulting from the existing structures:

The present structure at OH3 has contributed to the creation of a small headcut in the channel just

upstream of the structure. If not addressed, this headcut will result in ongoing cycles of channel incision in

the upstream reaches of the river, reducing any likelihood of future rehabilitation of these reaches.

It is thus strongly recommended that a condition of approval of the proposed structural repairs at this site

be that the headcut is addressed through the installation of a low gabion weir, designed to control the

effective channel gradient upstream of the headcut, and prevent the upstream migration of this feature.

The weir should be designed by an engineer with appropriate experience in this regard, and set far enough

back into the channel banks, such that it will not be bypassed or undermined by high flows.


The proposed wing wall designs would be associated with positive ecological impacts, as they would reduce

ongoing erosion and sedimentation of the channel in its downstream reaches.


As in the case of proposed construction activities at OH2, such impacts would include short-term

disturbance of the channel in the vicinity of the upstream headwall and the energy dissipation weir, the

potential passage of dewatered material into the watercourse and contamination of the watercourse by

construction associated materials such as cement. Such impacts would be considered negative, but

localised, taking place at low magnitude and over a short period of time only.

The above impacts would however be exacerbated if construction took place during the wet season when

the water table was high, or during a period when a storm event occurred.




Once again, it is recommended that the requirements of a comprehensive CEMP must be met during

construction (see Section 5).


Implementation of the proposed construction measures at OH3 would be likely to result in impacts of low

to negligible negative significance if the minor mitigation measures recommended were included.

Addressing the headcut upstream of the existing structure is considered an important measure to address

otherwise ongoing impacts that have been triggered by the existing structure.

4.4 Impacts associated with proposed construction at OH4 (Droogas River)


The design of the proposed repairs and replacement of the existing culvert wing walls are considered

unlikely, per se, to result in any impacts to freshwater ecosystems in the vicinity of OH4, and the existing

structure does not appear to have resulted in significant long-term changes to the river system.


These would include disturbance of the channel and river bank during removal and replacement of

damaged structures, damage to wetland vegetation (particularly if construction activities such as the

construction of a bypass road took place upstream of the bridge), potential accumulation of rubble waste in

the river or its margins if all waste associated with the project was not removed; contamination of the

watercourse by construction associated materials such as cement. Given the apparently high nutrient load

of the river, and an assumed high concentrations of total ammonia1, an increase in river pH as a result of

the passage of cement into the water, could trigger ammonia toxicity in the river. This is because ammonia

exists in two forms in water bodies, namely as potentially toxic un-ionised NH3, and as non-toxic ionized

NH4+. The proportion of the former increases with increasing alkalinity, particular where pH > 8 (DWAF

1996). Although such events would, in a construction process, be short-lived, their implications would

potentially be much longer-lived, if they resulted in mortalities to aquatic fauna.

The implications of a bypass road would potentially be of greatest concern along this channel that is

considered morphologically relatively unimpacted. In particular, disturbance of the channel upstream of

the culvert would be considered of medium-to-high negative significance, as it would result in high levels of

disturbance to a section of channel in (relatively) good condition, potentially triggering upstream erosion or

other impacts.

The above impacts would all be exacerbated if construction took place during the wet season when the

water table was high, or during a period when a storm event occurred.


i. Once again, the requirements of a comprehensive CEMP must be met during construction (see

Section 5), with particular attention paid to prevent of the passage of cementitious material into

the river.

ii. In addition, the following measures around the location and management of a bypass road are

considered essential:

a. The bypass may not be located on the upstream side of the existing road culvert and this

section of the river and its margins to a distance of 30m on either side of the river must be

managed as a no-go area for all construction personnel and their vehicles and materials;

b. Ideally, the construction process should be managed without a bypass road;

1 Note that no water quality data have informed these comments, which were based on the extent of algae in the river and the

proximity of herds of cattle



c. If a bypass is essential, it must be located downstream of the road, and should be subject

to the following controls:

o The bypass should allow for the passage of flows beneath it, whether in pipes or other

devices,

o The bypass should be completely removed following construction, and its footprint

rehabilitated, allowing for:

� regrading of the river bank to a river ecologist’s specifications

� replanting of the disturbed river bank and the re-establishment of Phragmites

australis vegetation, using the specifications for planting and short-term

maintenance outlined in Section 4.1.2B

� removal of all foreign material from the river bed and banks (pipes etc.).


Provided that the essential mitigation measures outlined in Section 4.4.2 are implemented, the negative

implications of the proposed road / culvert repairs could be limited to low levels significance only.

Construction activities, while thus quite acceptable from an ecological perspective, should however take

cognisance of the need for protection of the river in the vicinity of the road crossing, particularly given its

status as a system in a Phase 2 River FEPA – sub catchments earmarked for future rehabilitation.



4.5 Overall implications of proposed construction activities for watercourse PES

Table 4.1 outlines the estimated implications for Present Ecological State (PES) of the proposed

interventions at each watercourse, compared to the present and assuming implementation both with and

without mitigation measures.

Table 4.1

Estimated PES of affected watercourses, assuming implementation with and without mitigation

measures (with mitigation measures including measures for addressing impacts resulting from the

present structure)

Site

code

Pre-construction PES Estimated Post construction PES in the vicinity of

the crossing

(as assessed during site

visit)

With full mitigation Without mitigation

OH1 Class E Class D/E Class E

OH2 Class D Class D Class D

OH3 Class D Class D Class D (but degrading)

OH4 Class C /D Class C /D Class D



5 CONSTRUCTION PHASE MANAGEMENT RECOMMENDATIONS

Construction phase management of the various construction sites included in this project is aimed at

minimizing disturbance of watercourses and other wetlands, as a result of construction activities. In order

to achieve this, the following activities need to be considered in a Construction Phase Environmental

Management Programme (CEMP), namely activities that are likely to:

• cause bank disturbance;

• result in potential pollution of the water course as a result of allowing the passage (direct, or by

seepage, surface spillage or overflow) of pollutants such as sediment, cement, fuels, litter or other

waste into watercourses;

• increase the likelihood of invasion by alien plants;

• increase disturbance as a result of human access to river / wetland areas;

• negatively affect the success of planned river bank rehabilitation activities.

The following restrictions should be specifically included in the CEMP, with the proviso that, where it can be

shown that an alternative approach poses the same or lesser ecological risk, as agreed by an independent

ecologist; such an alternative may be considered instead. This measure allows for a degree of plasticity in

the implementation of the CEMP, and takes cognizance of the need, during construction, for alternative

approaches to be taken in the light of unforeseen practical difficulties in project implementation. The

following measures are recommended for inclusion in the CEMP:

• Work site and storage locations:

o no vehicles, fuels or construction materials are to be stored such that waste can leak, blow

or be washed into any watercourse; areas for the stockpiling of construction materials

should moreover be located at least 40m from the nearest watercourse;

o refueling of construction vehicles is to take place only from approved, bunded areas,

located at least 40m away from the nearest watercourse;

• Protection of the watercourse from disturbance:

o the construction disturbance area along the watercourse should be minimized, and this

minimum practical disturbance area should be demarcated before the start of construction

activities. All areas outside of this zone should be regarded as no-go areas during

construction, with the exception of personnel engaged in required alien clearing and bank

rehabilitation activities outside of construction disturbance zones;

• Where dewatering is required as part of construction activities, provision must be made for the

settlement of sediment in temporary sediment ponds or other devices, managed so as to prevent

the passage of sediment-rich water into the watercourse; such systems must also be designed such

that they do not result in the passage of concentrated flow into watercourses, likely to result in

erosion;

• Where the use of cement is required in or in the vicinity of watercourses, method statements must

be prepared by the contractor to show how prevention of contamination of watercourses is to be

achieved;

• Construction activities within watercourses must not take place during the wet season (i.e. any

activities requiring the diversion of flows must take place between October and April only), and

construction schedules should be managed within these time frames; and efforts must be made to

manage construction sites such that storm events occurring during construction do not result in

runoff from into watercourses from stockpiled or other construction material or waste;



• Rehabilitation activities specified in mitigation measures, including rehabilitation of temporary

bypasses or defunct structures must also take place outside of the wet season, and immediately

after the completion of construction activities at a particular site;

• Rehabilitation activities:

o requirements for alien clearing procedures should be carried out in accordance with

species-specific guidelines outlined by Working for Water documentation, or as

recommended by an experienced alien clearing specialist;

o bank rehabilitation activities should make provision for input by a river ecologist into the

final shaping and planting of these areas;

o any area accidentally disturbed during construction should be rehabilitated after

construction, with input from a riverine specialist where such areas lie within a

watercourse or other wetland;

• Waste management:

o adequate provision should be made for the containment of waste associated with the

construction site, including provision for toilets and litter management and removal;

o no tools or other construction materials may be washed in watercourses, and water used

for washing must be managed such that it does not contaminate any watercourse;

o all waste generated by construction activities (including rubble, litter etc.) is to be removed

from the site and disposed of at an appropriate approved site.

In the event that authorization by DEADP was granted for the proposed activities, Method Statements

would need to be developed by the Contractor that clearly showed how the above objectives and measures

are addressed in the proposed scope of Works.

Adherence to the CEMP would need to be a condition of authorisation for the project, and its

implementation should be overseen by a competent independent Environmental Control Officer or similar,

with allowance for input where necessary from a river ecologist.



6 NATIONAL WATER ACT COMPLIANCE CONSIDERATIONS

The preceding sections of this report have addressed the requirements of NEMA with regard to the

assessment of the various proposed road repair or rehabilitation activities. However, in addition to

requiring authorization in terms of NEMA, the proposed activities also need to comply with the

requirements of the National Water Act (NWA). In this regard, the NWA makes provision for a General

Authorisation (GA) relating to sections 21(c) and (i) of the NWA, but stipulates conditions that would guide

a decision as to the applicability of the General Authorisation.

Table 6.1, adapted from a template developed by Charl de Villliers for this project, addresses each of these

conditions / criteria with regard to the six proposed structural upgrades / rehabilitation projects assessed in

this report. This table should be used as the basis on which to approach DWA with regard to the extent to

which the proposed activities are likely to be generally authorised in terms of GN 1199 (2009), as opposed

to those requiring authorisation through a Water Use License Application (WULA) or other process.

Table 6.1

Assessment of proposed activities at each site against DWA criteria for General Authorisation of the

activities in terms of GN 1199 (2009).

Table template developed by Charl de Villliers for this project. Items ticked indicate that the

criterion has been met. Table completed, assuming FULL implementation of proposed

mitigation activities, and implementation without mitigation measures (bracketed).

Criteria for ‘General Authorisation’, in terms of GN1199 of 18-

12-2009)

OH1 OH2 OH3 OH4

(1) Water use must not cause detrimental impact on

characteristics of watercourse

√ (X) √ (X) √ (X) √ (X)

(2) Water use must not have a detrimental impact on....

(a) others’ use of water or land √ (X) √ (√) √ (X) √ (X)

(b) public health or safety √ (X) √ (√) √ (√) √ (√)

(3) Structures and hardened surfaces must not...

(a) be erosive √ (√) √ (√) √ (X) √ (√)

(b) be structurally unstable √ (X) √ (√) √ (X) √ (√)

(c) induce any flooding √(X) √ (√) √ (√) √ (√)

(d) be a health and safety hazard √ (X) √ (√) √ (√) √ (√)

(4) Water use must not result in detrimental....

(a) change in stability of a watercourse √(X) √ (√) √ (X) √ (X)

(b) change in physical structure of a watercourse √(X) √ (√) √ (X) √ (X)

(c) scouring, erosion or sedimentation √(X) √ (√) √ (X) √ (X)

(d) decline in diversity of communities, composition of

natural indigenous vegetation

√ (X) √ (√) √ (X) √ (X)

(5) Water use must not result in detrimental change in

quantity, velocity, pattern, timing, water level and

assurance of flow in a watercourse

√ (X) √ (√) √ (√) √ (X)

(6) Water use must not result in detrimental change in

water quality characteristics of watercourse

√(X) √ (√) √ (X) √ (X)

(7) Water use must not result in detrimental change to...

(a) breeding, feeding and migratory patterns of aquatic

biota, including migratory species

√ (?) √ (?) √ (?) √ (?)

(b) level of composition of biotopes and communities of

animals and micro-organisms

√ (?) √ (?) √ (?) √ (?)

(c) condition of aquatic biota √(X) √ (√) √ (X) √ (X)

Proximity to a watercourse

Wateruse must not lie within 500m of a wetland – in

this case, assumed to be the Riviersonderend

wetlands (tick means this criterion met)

√ √ √ √



7 CONCLUSIONS

This report has addressed the issues associated with the proposed rehabilitation / repair of four structures

located on Overberg Roads. With the inclusion of rehabilitation measures, none of these activities were

considered unacceptable from a freshwater ecology perspective.

Included in mitigation measures at two of the sites (OH1 and OH3) is the need to address impacts resulting

from the existing structures. Such measures are considered crucial elements relating to the successful

implementation of the proposed structures, to prevent ongoing, frequent disturbance to the river channel

as a result of flood damage that is not only ecologically devastating but is financially expensive as well (in

the case of OH1) and to prevent active headcut erosion of the channel at OH3. In the case of OH1,

however, it is noted that the major drivers of structural failure have probably involved various landuses

upstream, including the invasion of the river channel by alien vegetation. Given how extensive this

problem is in the region, it is recommended that stringent measures should be set in place regionally to

ensure that local landowners address this issue, using best practice clearing and rehabilitation measures, to

avoid ongoing damage to watercourses and road infrastructure, considering that while aliens appear to be

kept out of agricultural areas, they are allowed to spread unregarded along riparian zones, with the

resource value of these channels seemingly being disregarded, until severe damage accrues along access

points. This point has been reiterated in other reports by FCG, assessing flood-damaged roads and road-

damaged rivers in the Overberg area.



8 REFERENCES

Brown, C. and Fowler, J. 2000. Breede River Basin Study. Preliminary Assessment of the Breede River Basin.

Southern Waters Report for MBB, Ninham Shand and Jakoet & Associates, for the Department

of Water Affairs and Forestry.

Department of Water Affairs and Forestry. 1996. South African Water Quality Guidelines. Volume 7:

Aquatic Ecosystems. Department of Water Affairs and Forestry. Pretoria.

Department of Water Affairs and Forestry. 2004. Development of a framework for the assessment of

wetland ecological integrity in South Africa. Phase 1: Situation Analysis. by MC Uys. Contributors

G Marneweck and P Maseti. Report No. 0000/00/REQ/0904 ISBN No.: 0-621-35474-0. Resource

Quality Services, Department of Water Affairs and Forestry, Pretoria, South Africa.

Department of Water Affairs and Forestry. 2005. A Practical Field Procedure for Identification and

Delineation of Wetlands and Riparian Areas. Department of Water Affairs and Forestry, Pretoria

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APPENDICES



APPENDIX A: RESULTS OF EIS DETERMINATIONS

Table A1 presents the EIS scores attributed to river reaches at the different sites assessed in this study,

using the methodology of DWAF (1999) as outlined in Section 3.1.3. Note that, due to a lack of data, the

biotic component of the sites was not considered. Assessments took account of the irreparable level of

disturbance of some systems (e.g. the Meul River), as well as of the level of agricultural development in the

broader area, making riverine corridors increasingly important at a landscape level.

Table A1 Results of EIS assessments carried out at proposed road works sites

Criteria OH1 OH2 OH3 OH4

HABITAT

Diversity of aquatic habitat types 1 1 1 2

Refuge value of habitat types 1 1 1 2

Sensitivity of habitat to flow changes 2 2 2 2

Sensitivity of habitat to WQ changes 3 3 3 2

Migration route/corridor 1 1 2 2

Protected/natural areas 0 1 1 1

Median score 1 1 1.5 2

EIS Category Low/ Marginal Moderate

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