SLANG RIVER LOW-LEVEL CROSSING ECOLOGICAL IMPACT … River 287_RA090216... · EOH Coastal &...

SLANG RIVER LOW-LEVEL CROSSING

ECOLOGICAL IMPACT ASSESSMENT

Prepared for:

Afri-Coast Engineers SA (Pty) Ltd 14 Rose Street (Cnr Rose & Havelock Streets)

Central, Port Elizabeth, 6001

On behalf of

Eastern Cape Department of Roads and Public Works Qhasana Building, Independence Avenue, Bhisho, 5605

Prepared by:

Coastal and Environmental Services (Pty) Ltd, trading as

EOH Coastal & Environmental Services 13 Stanley street, Richmond Hill, Port Elizabeth, 6001

Also in Grahamstown, East London, Gauteng, Cape Town and Maputo (Mozambique)

www.cesnet.co.za

January 2016

http://www.cesnet.co.za/

This Report should be cited as follows: EOH Coastal & Environmental Services, January 2016: Slang River low-level crossing Ecological Impact Assessment, EOH CES, Port Elizabeth.

Slang River low-level crossing Ecological Impact Assessment – January 2016

EOH Coastal & Environmental Services Slang River low-level crossing i

REVISIONS TRACKING TABLE

EOH Coastal and Environmental Services

Report Title: Slang River low-level crossing Ecological Impact Assessment Report Version: Final Draft Project Number: 287

Name Responsibility Signature Date

Ms. Tarryn Martin Reviewer

September 2015

Mrs. Kim Brent Lead Author

August / September 2015

Ms. Belinda Huddy Report Assistance

July 2015

Mr Craig Sholto-Douglas

Wetland Delineation

January 2016

Copyright This document contains intellectual property and propriety information that are protected by

copyright in favour of EOH Coastal & Environmental Services (CES) and the specialist consultants. The document may therefore not be reproduced, used or distributed to any third party without the prior written consent of CES. The document is prepared exclusively for submission to Africoast

Engineers Pty (Ltd) in South Africa and the Eastern Cape Department of Roads and Public Works, and is subject to all confidentiality, copyright and trade secrets, rules intellectual property law and

practices of South Africa.


EOH Coastal & Environmental Services Slang River low-level crossing ii

THE PROJECT TEAM Mrs Kim Brent (Lead Author) Kim holds a BSc degree with majors in Botany and Geography as well as a BSc (Hons) degree in Botany focussing on Environmental Management and GIS systems; both from NMMU. Her honours year focussed on Environmental impact assessments, environmental management and Geographic Information systems. Kim‘s interests include Environmental impact assessments, Geographic information systems and Botanical assessments. Kim has over 4 years‘ experience in the consultancy environment and is currently employed in the Port Elizabeth office of CES. Ms Belinda Huddy (Report Assistance) Belinda holds an MPhil in Environmental, Society and Sustainability and a Bachelor of Business Science (Hons) in Economics, both obtained from the University of Cape Town. Her master's dissertation explored alternative values attached to the Cape Town Talent Exchange. Her honours thesis investigated the determinants of the success and failures of the bio-diesel industry, focusing on a jatrohpa plantation in Zambia. Courses in her master's degree include Theory and Practice of Environment Management, Managing Complex Human-Ecological Systems, Environmental Law and Cultural Geography. The relevant courses in her honours degree included Environmental Economics and Natural Resource Economics. Ms Tarryn Martin Pri.Sci.Nat (Reviewer) Tarryn holds a BSc (Botany and Zoology), a BSc (Hons) in African Vertebrate Biodiversity and an MSc with distinction in Botany from Rhodes University. Tarryn‘s Master‘s thesis examined the impact of fire on the recovery of C3 and C4 Panicoid and non-Panicoid grasses within the context of climate change for which she won the Junior Captain Scott-Medal (Plant Science) for producing the top MSc of 2010 from the South African Academy of Science and Art as well as an Award for Outstanding Academic Achievement in Range and Forage Science from the Grassland Society of Southern Africa. She conducts vegetation assessments including vegetation and sensitivity mapping to guide developments and thereby minimise their impacts on sensitive vegetation. Tarryn has conducted a number of vegetation and impact assessments in Mozambique (to IFC standards) which include the Lurio Forestry Project in Nampula, the Syrah Graphite Mine in Cabo del Gado and the Baobab Iron Ore Mine in Tete, Mozambique. Tarryn has also co-designed and implemented the Terrestrial Monitoring Program for Kenmare, MOMA, a heavy minerals mine in Mozambique. This monitoring program includes an assessment of forest health. She has also worked on the Lesotho Highlands Development Authority botanical baseline survey for phase 2 of the Lesotho Highlands Water Project. Mr Craig Sholto-Douglas (Wetland Delineation and Assessment) Craig holds a BSc (Env Sci and Zoology) and a BSc (Hons) in Environmental Science. He is currently completing his MSc in Environmental Science, focussing on factors influencing survivorship of Portulacaria afra (Spekboom) cuttings, in attempts to restore degraded lands in the Greater Addo Elephant National Park. His academic background includes courses in Urban Forestry and Greening, Non-Timber Forest Products, Community-Based Natural Resource Management and G.I.S. Research projects include a leopard (Panthera pardus) population survey and invasive plant species analyses. Craig has consulting experience in the restoration ecology and natural resource management fields, with focus on the Subtropical Thicket Restoration Project (STRP). Since working at EOH CES, Craig has been involved in Wind Farm ECO work, EIA‘s and a number of faunal specialist studies. Craig has been involved in numerous wetland delineations and assessments in the Eastern Cape, including the Oyster Bay WEF Ecological Assessment and SANRAL National Road Upgrade Wetland Assessments.


EOH Coastal & Environmental Services Slang River low-level crossing i

ENVIRONMENTAL ASSESSMENT PRACTITIONER DECLARATION OF INDEPENDENCE

Role on Study Team Declaration of independence

Report Reviewer I TARRYN MARTIN declare that I am an independent consultant and have no business, financial, personal or other interest in the proposed development of Social Housing in the Eastern Cape, application or appeal in respect of which I was appointed other than fair remuneration for work performed in connection with the activity, application or appeal. There are no circumstances that compromise the objectivity of my performing such work. SIGNATURE:

Report production I KIM BRENT declare that I am an independent consultant and have no business, financial, personal or other interest in the proposed development of Social Housing in the Eastern Cape, application or appeal in respect of which I was appointed other than fair remuneration for work performed in connection with the activity, application or appeal. There are no circumstances that compromise the objectivity of my performing such work. SIGNATURE:

Report production I BELINDA HUDDY declare that I am an independent consultant

and have no business, financial, personal or other interest in the proposed development of Social Housing in the Eastern Cape, application or appeal in respect of which I was appointed other than fair remuneration for work performed in connection with the activity, application or appeal. There are no circumstances that compromise the objectivity of my performing such work. SIGNATURE:

Report production I CRAIG SHOLTO-DOUGLAS declare that I am an independent

consultant and have no business, financial, personal or other interest in the proposed development of Social Housing in the Eastern Cape, application or appeal in respect of which I was appointed other than fair remuneration for work performed in connection with the activity, application or appeal. There are no circumstances that compromise the objectivity of my performing such work. SIGNATURE:


EOH Coastal & Environmental Services Slang River low-level crossing ii

EXECUTIVE SUMMARY Background The Slang River crossing which is located on the district road (DR) 01763, North of Oyster Bay and between the Kouga Local Municipality and Humansdorp has been damaged by a flood event and numerous heavy rain events. Consequently, a section of the crossing has become unusable. EOH Coastal & Environmental Services (CES) has been approached by Africoast Engineers on behalf of the Eastern Cape Department of Roads and Public Works to to apply for environmental authorization by conducting a Basic Assessment and all related specialist assessments (ecological) for the rehabilitative maintenance to the Slang River low-level crossing. The proposed reconstruction works will entail: the establishment of a camp site (including storage area); rehabilitation of the damaged crossing, with work being limited to the existing footprint; and a temporary diversion of stream flow through the construction area using temporary pipes. A water use authorisation in terms of the National Water Act (Act 36 of 1998) sections 21 (i) and (c) will be applied for as the proposed bridge rehabilitation impedes or diverts the natural flow of the watercourse and also alters the bed, banks, course and characteristics of a water course. Objective and approach The main objective of this report is to assess the Present Ecological State (PES) of the Slang River as well as the potential impact that the proposed reconstruction of the low-level crossing may have on the river and the riparian and terrestrial habitat. The proposed project and surrounding areas were described using a two-phased approach. Firstly, a desktop assessment of the project area was conducted in terms of current vegetation classifications and biodiversity programmes and plans. Information was also collected to determine the PES and Ecological Importance and Sensitivity (EIS) of the project area. These analyses were based on the models developed by the Department of Water and Sanitation, with the results producing various ratings. Secondly, site visits were conducted to assess the actual ecological state, current land-use, identify potential sensitive ecosystems and identify plant species associated with the proposed project activity. The ecological sensitivity of the study area was determined on a broad scale. The approach identifies zones of, high, moderate and low sensitivity according to a system developed by CES and used in numerous proposed development studies. Key findings The Present Ecological State (PES) of the Slang River and its associated wetlands is described as largely modified (Category D). A large loss of natural habitat, biota and basic ecosystem functions has occurred. Vegetation composition has been largely altered and introduced alien and/or ruderal species dominate the site. The area is highly degraded as a result of direct and indirect anthropogenic activities and has consequently been assigned a moderate to low sensitivity. The adjacent road and agricultural land has been classified as having a low sensitivity due to their degraded and transformed nature. Reduction in flow due to impoundments upstream and downstream of the project area, algal growth within the river, erosion and sediment deposition, alien infestation, and current land use (e.g. agricultural practice) have contributed to the modification of the river and wetland systems. A total of twenty four (24) species were identified within the project area. Twelve (12) of these species were identified as species of conservation concern listed on the South African Red Data and is classified as species of ―Least Concern‖ and one (1) species as declining. None of the identified species are protected in the Eastern Cape PNCO list or on the NEM:BA list. No protected tree species were recorded to occur within the project area. Four (4) alien species were identified on site.


EOH Coastal & Environmental Services Slang River low-level crossing iii

Identified impacts Associated impacts identified with the proposed low-level crossing were not deemed insurmountable. No high rated impacts were identified and all other impacts (pre-mitigation) are easily mitigated. A summary of impacts associated with the low level crossing pre and post mitigation, as well as the no-go alternative is included below.

Summary of impacts associated with the low level crossing pre and post mitigation. The no-go alternative has also been included for comparative purposes.

IMPACTS WITHOUT

MITIGATION WITH MITIGATION NO-GO

CONSTRUCTION PHASE

Loss of Riparian vegetation Low Low Moderate

Loss of Alien vegetation Low + Moderate + High

Loss of floral biodiversity (general)

Moderate Low Low

Loss of SCC Moderate Low Low

Impacts on sensitive ecosystems in terms of erosion and sedimentation

Moderate Low High

Impacts on sensitive ecosystems in terms of pollution

Moderate Low Moderate

Temporary diversion of stream flow

Moderate Moderate Moderate

Physical destruction of wetland habitat

Moderate Low High

Sedimentation and erosion within the wetland system


OPERATIONAL PHASE

Invasion of alien plant species Moderate Low + High

Reduction of erosion and sedimentation

Low + Moderate + High


EOH Coastal & Environmental Services Slang River low-level crossing iv

TABLE OF CONTENTS 1. INTRODUCTION ..................................................................................................................... 1

1.1 Background ..................................................................................................................... 1 1.2 Project description and locality ........................................................................................ 1 1.3 Objectives and Terms of Reference................................................................................. 4 1.4 Approach ......................................................................................................................... 4 1.5 Limitations and assumptions ........................................................................................... 7

2 RELEVANT LEGISLATION .................................................................................................... 8 2.1 National Environmental Management Act (No. 107 of 1998) ........................................... 8 2.2 National Environmental Management: Biodiversity Act (No. 10 of 2004) ......................... 8 2.3 National Water Act (No.36 of 1998) ................................................................................. 9 2.4 National Forest Act (No.84 of 1998)............................................................................... 10 2.5 Species of Conservation Concern (SCC) ....................................................................... 10

3 DESCRIPTION OF THE PHYSICAL ENVIRONMENT .......................................................... 13 3.1 Climate .......................................................................................................................... 13 3.2 Geology and Soils (Source: www.geoscience.org.za, AGIS 2015) ................................ 13 3.3 Topography ................................................................................................................... 14 3.4 Socio-economic aspects and Current land use .............................................................. 14

4 DESCRIPTION OF THE ECOLOGICAL ENVIRONMENT .................................................... 17 4.1 Aquatic Environment ..................................................................................................... 17

4.1.1 Water Management Area (WMA) ............................................................................... 17 4.1.2 Background to the Slang River within the project area ............................................... 18 4.1.3 The Slang Estuary ..................................................................................................... 19

4.2 Terrestrial and Riparian environment ............................................................................. 22 4.2.1 SANBI Vegetation Map .............................................................................................. 22 4.2.2 Subtropical Thicket Ecosystem Programme (STEP) .................................................. 23 4.2.3 Eastern Cape Biodiversity Conservation Plan (ECBCP) ............................................ 25 4.2.4 Present Ecological State (PES) of the Slang River and associated wetlands ............. 28

4.3 Site survey: description of vegetation/land cover ........................................................... 29 4.3.1 Riparian Vegetation ................................................................................................... 29

4.4 Floristics ........................................................................................................................ 34 4.4.1 Species of Conservation Concern .............................................................................. 34 4.4.2 Alien Species ............................................................................................................. 36

5 WETLAND DELINEATION AND ASSESSMENT ................................................................. 38 5.1 Approach ....................................................................................................................... 38 5.2 Wetland definition .......................................................................................................... 38 5.3 Wetland Importance ...................................................................................................... 38 5.4 Tools available to define wetlands and watercourses .................................................... 39

5.4.1 National Freshwater Ecosystem Priority Areas .......................................................... 39 5.4.2 WET-Health and Present Ecological State ................................................................. 40

6 PHYSICAL DESCRIPTION OF WETLAND AND AQUATIC ENVIRONMENT ...................... 45 6.1 Introduction .................................................................................................................... 45 6.2 Collection of site data .................................................................................................... 47 6.3 Present Ecological State (PES) ..................................................................................... 47

6.3.1 Hydrology .................................................................................................................. 47 6.3.2 Geomorphology ......................................................................................................... 47 6.3.3 Vegetation ................................................................................................................. 48 6.3.4 Overall PES of Identified Wetlands ............................................................................ 49 6.3.5 Photographs of Wetlands........................................................................................... 52

7 BIODIVERSITY AND SENSITIVITY ASSESSMENT ............................................................ 54 7.1 Sensitivity analysis and site sensitivity ........................................................................... 54

8 IMPACT IDENTIFICATION AND ASSESSMENT ................................................................. 55 8.1 Planning and Design Phase .......................................................................................... 55 8.2 Construction phase ........................................................................................................ 55

8.2.1 Issue 1: Loss of Vegetation communities ................................................................... 55 8.2.2 Issue 2: Loss of Biodiversity ...................................................................................... 56 8.2.3 Issue 3: Disruption of Ecosystem Function and Process ............................................ 58


EOH Coastal & Environmental Services Slang River low-level crossing v

8.2.4 Issue 4: Impacts on wetlands and wetland function ................................................... 60 8.3 Operational Phase ......................................................................................................... 61

8.3.1 Issue 4: Disruption of Ecosystem Function and Process ............................................ 61 8.4 Decommissioning Phase ............................................................................................... 62 8.5 Cumulative Impacts ....................................................................................................... 62

9 IMPACT STATEMENT, CONCLUSION & RECOMMENDATIONS ....................................... 63 9.1 Conclusions ................................................................................................................... 63 9.2 Current status ................................................................................................................ 63 9.3 Comparison of impacts .................................................................................................. 63 9.4 Invasion of alien species ................................................................................................ 64

10 REFERENCES...................................................................................................................... 65

LIST OF FIGURES Figure 1.1: Locality map illustrating the position of the project area (Source: Africoast Engineers). ................ 3 Figure 3.1: Map indicating the geology of the proposed ................................................................................. 14 Figure 3.2: Landcover classification of the proposed project area in relation to the surrounding area. .......... 15 Figure 4.1: Map indicating the location of the project area including the identification of sensitive

environments (Source: Africoast Engineers) ........................................................................................... 20 Figure 4.2: Map indicating the location of the project area in the relevant Water Management Area (Source:

Africoast Engineers) ................................................................................................................................ 21 Figure 4.3: National Vegetation Map illustrating the vegetation type found within the project area. .............. 23 Figure 4.4: Regional Vegetation Map illustrating the vegetation type found within the project area as

classified by STEP (2006). ...................................................................................................................... 24 Figure 4.5: Transformed areas as classified by STEP (2006). ........................................................................ 25 Figure 4.6: Critical Biodiversity Areas (CBA) as classified by ECBCP (2007). ............................................... 26 Figure 4.7: BLMC Land management classes as classified by ECBCP (2007). ............................................. 27 Figure 5.1: The HGM types for South African Inland wetlands (SANBI, 2009). .............................................. 41 Figure 5.2: The steps involved in the WET-Health Level 1 rapid assessment (MacFarlane et al. 2007). ...... 43 Figure 6.1: National Freshwater Ecosystem Priority Areas (NFEPA) wetlands and wetland conditions ........ 46 Figure 6.2: Delineated wetlands and sensitive areas ...................................................................................... 51

LIST OF TABLES Table 1.1: Description of A – F ecological categories based on Kleynhans et al., (2005) ................................ 4 Table 1.2: Criteria used for the analysis of the sensitivity of the area ............................................................... 6 Table 2.1: NEMBA classes and explanations.................................................................................................. 11 Table 2.2: South African Red Data List Categories (SANBI, 2013) ................................................................ 11 Table 4.1: Present Ecological State (PES) of the Slang River ........................................................................ 29 Table 4.2: Species recorded on site. Those recorded in the Red data list, PNCO, CITES, NEMBA and CARA

has been classified according to each list and discussed below the table. ............................................. 34 Table 4.3: Alien invasive species present on site ............................................................................................ 36 Table 5.1: Description of A – F ecological categories based on Kleynhans (1996, 1999). ............................. 44 Table 6.1: Overall PES scores and ratings for the assessed wetlands. .......................................................... 50 Table 9.1: Summary of impacts associated with the low level crossing pre and post mitigation. The no-go

alternative has also been included for comparative purposes. ............................................................... 64


EOH Coastal & Environmental Services Slang River low-level crossing 1

1. INTRODUCTION

1.1 Background The Slang River crossing is located on the district road (DR) 01763, North of Oyster Bay and between the Kouga Local Municipality and Humansdorp (Figure 1.1). Since 2011, the Slang River crossing has been damaged by a flood event and since then a number of heavy rain events contributed to the condition of the current low-level crossing. Consequently, a section of the crossing has become unusable and this is undermining the integrity of the crossing to support vehicle traffic (See plate 1 below). This also poses a threat to farmers in terms of safety as well as the local public that uses this road.

Plate 1: Photos of the damaged Slang River Crossing (Source: Africoast Engineers)

1.2 Project description and locality EOH Coastal & Environmental Services (CES) has been approached by Africoast Engineers on behalf of the Eastern Cape Department of Roads and Public Works to to apply for environmental authorization by conducting a Basic Assessment and all related specialist assessments (Ecological) for the rehabilitative maintenance to the Slang River low-level crossing. The proposed low-level crossing is located along a ―dirt‖ or un-tarred district road across the perennial Slang River (or Slangrivier), approximately 20km north east of the coastal town of Oyster Bay, in the Eastern Cape.



The area falls within Ward 1 of the Kouga Local Municipality within the broader Cacadu District Municipality, otherwise known as Sarah Baartman District Municipality. The population in the Kouga Local Municipality is approximately 98 588 with an average growth rate 2.4% per annum, which is relatively high in comparison to the district and provincial growth rates of 1.1% and 0.3%, respectively. The Kouga Local Municipality is the Water Services Authority (WSA) for the jurisdiction, and is thus responsible for the provision of water services as well as for drafting all water services development plans for the area. The proposed reconstruction works will entail (in summary) (Source: Africoast Engineers) –

Camp site establishment (including storage area)

Rehabilitation of the damaged crossing, with work being limited to the existing footprint

Temporary diversion of stream flow through the construction area using temporary

pipes

A water use authorisation in terms of the National Water Act (Act 36 of 1998) sections 21 (i) and (c) will be applied for as the proposed bridge rehabilitation impedes or diverts the natural flow of the watercourse and also alters the bed, banks, course and characteristics of a water course.



Figure 1.1: Locality map illustrating the position of the project area (Source: Africoast Engineers).



1.3 Objectives and Terms of Reference The main objective of this report is to assess the Present Ecological State (PES) of the Slang River as well as the potential impact that the proposed reconstruction of the low-level crossing may have on the river and the riparian and terrestrial habitat. The following terms of reference were used for the objectives of this study:

Describe the study area in terms of land cover, vegetation and aquatic features. This aspect of the report will specifically include the identification of -

o Areas of high biodiversity; o The presence of species of conservation concern, including sensitive, endemic and

protected species; o Rapid assessment of river/riparian integrity and assessment of ecological importance and

sensitivity. o The presence of areas sensitive to invasion by alien species; and o The presence of conservation areas and sensitive habitats where disturbance should be

avoided or minimised.

Review relevant legislation, policies, guidelines and standards.

An assessment of the potential direct and indirect impacts resulting from the proposed development both on the footprint and the immediate surrounding area during construction and operation and

A detailed description of appropriate mitigation measures that can be adopted to reduce negative impacts for each phase of the project, where required

1.4 Approach The proposed project and surrounding areas were described using a two-phased approach. Firstly, a desktop assessment of the project area was conducted in terms of current vegetation classifications and biodiversity programmes and plans. This included the consideration of:

The South African Vegetation Map (Mucina and Rutherford, 2006);

The Subtropical Thicket Ecosystem Programme (STEP, 2006)

The Eastern Cape Biodiversity Conservation plan (ECBCP, 2007)

The National Freshwater Ecosystem Priority Areas (NFEPA) project (2011/2014) Information was also collected to determine the PES and Ecological Importance and Sensitivity (EIS) of the project area. These analyses were based on the models developed by the Department of Water and Sanitation, with the results producing various ratings (A – F) and is summarised in Table 1.1 below. Table 1.1: Description of A – F ecological categories based on Kleynhans et al., (2005) ECOLOGICAL

CATEGORY ECOLOGICAL DESCRIPTION

MANAGEMENT

PERSPECTIVE

A

Unmodified, natural.

Protected systems; relatively

untouched by human hands; no

discharges or impoundments

allowed

B

Largely natural with few modifications. A small

change in natural habitats and biota may have

taken place but the ecosystem functions are

essentially unchanged.

Some human-related

disturbance, but mostly of low

impact potential

C

Moderately modified. Loss and change of natural

habitat and biota have occurred, but the basic

ecosystem functions are still predominantly

unchanged.

Multiple disturbances

associated with need for

socio-economic

development, e.g.



ECOLOGICAL

CATEGORY ECOLOGICAL DESCRIPTION

MANAGEMENT

PERSPECTIVE

D

Largely modified. A large loss of natural habitat,

biota and basic ecosystem functions has occurred.

impoundment, habitat

modification and water

quality degradation

E

Seriously modified. The loss of natural habitat,

biota and basic ecosystem functions is extensive. Often characterized by high

human densities or extensive

resource exploitation.

Management intervention is

needed to improve health,

e.g. to restore flow patterns,

river habitats or water quality

F

Critically / Extremely modified. Modifications have

reached a critical level and the system has been

modified completely with an almost complete loss

of natural habitat and biota. In the worst instances

the basic ecosystem functions have been

destroyed and the changes are irreversible.

Further to the above, a site visit was conducted (9 June 2015) to assess the actual ecological state, current land-use, identify potential sensitive ecosystems and identify plant species associated with the proposed project activity. During the site surveys, selected sites which represented natural habitats were sampled for species richness and abundance and vegetation structure. A stratified random sampling approach was adopted, whereby initial assumptions were made about the diversity of vegetation from satellite imagery, existing vegetation maps and previous studies conducted in the area. In this way the time available was used much more efficiently than in random sampling, but there is a risk of bias and the eventual results may simply ‗prove‘ the assumptions. The aim of this visit was to characterise and describe each vegetation community as well as identifying areas of high sensitivity and species of conservation concern. It is however, important to note areas of high sensitivity as well as species of conservation concern have been identified as far as possible, either from records from the project area or a review of their habitat requirements and whether or not these habitats occur in within the project area. The primary aim of this study was to identify whether areas of high sensitivity will be subject to significant impacts from the proposed activity. Aspects that would increase impact significance include:

Presence of plant species of conservation concern.

Vegetation types of conservation concern.

Areas of high biodiversity.

The presence of important process areas such as: o Ecological corridors o Water bodies (including wetlands & rivers) o Topographical features (especially steep and rocky slopes that provide niche habitats for

both plants and animals) Sensitivity assessment This section of the report explains the approach to determining the ecological sensitivity of the study area on a broad scale. The approach identifies zones of, high, moderate and low sensitivity according to a system developed by CES and used in numerous proposed development studies. It must be noted that the sensitivity zonings in this study are based solely on ecological characteristics and social and economic factors have not been taken into consideration. The sensitivity analysis described here is based on 10 criteria which are considered to be of importance in determining ecosystem and landscape sensitivity. The sensitivity criteria described in Table 1.2 below were applied to the study area. The entire site was then categorised into zones of HIGH, MODERATE or LOW sensitivity. Although very simple,



this method of analysis provides a good, yet conservative and precautionary assessment of the ecological sensitivity. Table 1.2: Criteria used for the analysis of the sensitivity of the area

CRITERIA LOW SENSITIVITY 1

MODERATE SENSITIVITY

5

HIGH SENSITIVITY 10

1 Topography Level, or even Undulating; fairly steep slopes

Complex and uneven with steep slopes

2 Vegetation - Extent or habitat type in the region

Extensive Restricted to a particular region/zone

Restricted to a specific locality / site

3 Conservation status of flora or habitats

Well conserved independent of conservation value

Not well conserved, moderate conservation value

Not conserved - has a high conservation value

4 Species of conservation concern - Presence and number

None, although occasional regional endemics

No endangered or vulnerable species, some indeterminate or rare endemics

One or more endangered and vulnerable species, or more than 2 endemics or rare species

5 Habitat fragmentation leading to loss of viable populations

Extensive areas of preferred habitat present elsewhere in region not susceptible to fragmentation

Reasonably extensive areas of preferred habitat elsewhere and habitat susceptible to fragmentation

Limited areas of this habitat, susceptible to fragmentation

6 Biodiversity contribution

Low diversity, or species richness

Moderate diversity, and moderately high species richness

High species diversity, complex plant and animal communities

7 Visibility of the site or landscape from other vantage points

Site is hidden or barely visible from any vantage points with the exception in some cases from the sea.

Site is visible from some or a few vantage points but is not obtrusive or very conspicuous.

Site is visible from many or all angles or vantage points.

8 Erosion potential or instability of the region

Very stable and an area not subjected to erosion.

Some possibility of erosion or change due to episodic events.

Large possibility of erosion, change to the site or destruction due to climatic or other factors.

9 Rehabilitation potential of the area or region

Site is easily rehabilitated.

There is some degree of difficulty in rehabilitation of the site.

Site is difficult to rehabilitate due to the terrain, type of habitat or species required to reintroduce.

10 Disturbance due to human habitation or other influences (Alien invasives)

Site is very disturbed or degraded.

There is some degree of disturbance of the site.

The site is hardly or very slightly impacted upon by human disturbance.

A Geographical Information System (GIS) map was then drawn up depicting the different zones of sensitivity using available aerial imagery and relating this to the information gathered from the field survey.



1.5 Limitations and assumptions This report is based on currently available information and, as a result, the following limitations and assumptions are implicit:–

1. The report is based on a project description taken from design specifications for the proposed low-level crossing provided to CES by the engineers, that has not yet been finalised, and which is likely to undergo a number of iterations and refinements before it can be regarded as definitive;

2. Faunal aspects has not been included in this report. 3. Species of conservation concern are difficult to find and difficult to identify, thus species

described in this report do not comprise an exhaustive list. It is almost certain that additional species of conservation concern will be found during construction and operation of the development.

4. For the sake of this study, one survey was deemed sufficient to determine the status of the study area.

5. Ecological descriptions of the natural environment are based on limited fieldwork and available literature.



2 RELEVANT LEGISLATION Environmental legislation relevant to the proposed Slang River low-level crossing is summarised below. Biodiversity Plans and Programmes are discussed in Chapter 4 where they are used to describe the desktop ecological conditions.

2.1 National Environmental Management Act (No. 107 of 1998) Relevant Sections of the Act: Section 2, 23, 24, 24-1, 28 -33 Applications for the Slang River low-level crossing:

Application of the NEMA principles (e.g. need to avoid or minimise impacts, use of the precautionary principle, polluter pays principle, etc.)

Application of fair decision-making and conflict management procedures are provided for in NEMA.

Application of the principles of Integrated Environmental Management and the consideration, investigation and assessment of the potential impact of existing and planned activities on the environment; socio-economic conditions; and the cultural heritage.

Implications for the proposed Slang River low-level crossing: o In terms of Section 28, every person who causes; has caused, or may cause significant

pollution or degradation of the environment must take reasonable measures to prevent pollution or rectify the damage caused.

2.2 National Environmental Management: Biodiversity Act (No. 10 of 2004) Relevant Sections of the Act: Section 50-62, 63-77, 75 Objectives of the Act The objectives of the Act include inter alia: To provide for:

The management and conservation of biological diversity within the Republic and of the components of such biological diversity;

o The use of indigenous biological resources in a suitable manner; o The fair and equitable sharing of benefits arising from bio-prospecting of genetic

material derived from indigenous biological resources; and o To give effect to ratified international agreements relating to biodiversity which are

binding on the Republic.

To provide for co-operative governance in biodiversity management and conservation; and

To provide for a South African National Biodiversity Institute to assist in achieving the objectives of the Act.

Threatened or protected ecosystems and species Sections 50-62 provide details relating to the protection of threatened or protected ecosystems and species. A person may not carry out a restricted activity involving a specimen of a listed threatened or protected species without a permit (Section 56-1). Alien and invasive species Sections 63-77 provide details relating to the alien and invasive species with the purpose of preventing the introduction and spread, managing and controlling, and eradicating alien and invasive species.



Implications for the Slang River low-level crossing: o An invasive species management, control and eradication plan for land/activities under their

control should be developed, as part of their environmental plans in accordance with section 11 of NEMA.

2.3 National Water Act (No.36 of 1998) Purpose of the Act (Section 2) The purpose of the Act is to ensure that the Nation‘s water resources are protected, used, developed, conserved and controlled in ways which take into account, including: d) Promoting sustainable use of water. g) Protect aquatic and associated ecosystems and their biological diversity. h) Reducing and preventing pollution and degradation of water resources. Protection of water resources (Section 12-20) Provides details of measures intended to ensure the comprehensive protection of all water resources, including the water reserve and water quality. With respect to the establishment of water quality objectives, objectives may relate to (Section 13):

the presence and concentration of particular substances in the water

the characteristics and quality of the water resource and the in-stream and riparian habitat

the characteristics and distribution of aquatic biota

the regulation and prohibition of in-stream and land-based activities which may affect the quantity and quality of the water resources

Section 19 deals with Pollution Prevention (Part 4) The person (including a municipality) who owns, controls occupies or uses the land in question, is responsible for taking reasonable measures to prevent pollution of water resources. If the measures are not taken, the catchment management agency concerned, may itself do whatever is necessary to prevent the pollution or remedy its effects and recover all reasonable costs from the persons responsible for the pollution. The ‗reasonable measures‘ which have to be taken may include measures to:

a) Cease, modify or control any act or process causing the pollution; b) Comply with any prescribed waste standard or management practice; c) Contain or prevent the movement of pollutants; d) Eliminate any source of the pollution; e) Remedy the effects of the pollution; and f) Remedy the effect of any disturbance to the bed and banks of a watercourse.

With respect to pollution of rivers, the following definition is relevant when considering the potential impacts of development on water resources. Pollution may be deemed to occur when the following are affected:

a) the quality, pattern, timing, water level and assurance of instream flow; b) the water quality, including the physical, chemical and biological characteristics of the

water; c) the character and condition of the in-stream and riparian habitat; d) the characteristics, condition and distribution of the aquatic biota.

The Act defines ‗instream habitat‘ as including the physical structure of a watercourse and the associated vegetation in relation to the bed of the watercourse. Riparian ecosystems ‗Riparian habitat‘ includes the physical structure and associated vegetation of the areas associated with a watercourse which are commonly characterised by alluvial soils, and which are inundated or flooded to an extent and with a frequency sufficient to support vegetation of species and physical structure distinct from those of adjacent land areas.



Section 21 deals with the Use of Water Section 21 (a-k) describes activities defined as a water use under the act. These activities may only be undertaken subject to the application for, and issue of, a water use licence.

Implications for the Slang River low-level crossing: o Appropriate measures must be taken to prevent the pollution of water courses. o Riparian zones must be protected. o Construction within a water course or within 500 metres of a wetland will require a Water

Use licence under section 21 (c) & (i) issued by the Department of Water and Sanitation.

2.4 National Forest Act (No.84 of 1998) Any area that has vegetation which is characterised by a closed and contiguous canopy and under storey plant establishment is defined as a ‗forest‘ and as a result falls under the authority of the Department of Agriculture, Forestry and Fisheries (DAFF): Forestry sector. A clause in Chapter 3, Part 1 covers: Prohibition on destruction of trees in natural forests. Section 7 (1) No person may cut, disturb, damage or destroy any indigenous living tree in, or remove or receive any such tree from, a natural forest except in terms of (a) A licence issued under subsection (4) or section 23. Effect of setting aside protected areas Section 10 (1) No person may cut, disturb, damage or destroy any forest produce in, or remove or receive any forest produce from, a protected area, except—

a) in terms of the rules made for the proper management of the area in terms of section 11(2)(b);

b) in the course of the management of the protected area by the responsible organ of State or person;

c) in terms of a right of servitude: d) in terms of the authority of a licence granted under section 7(4) or 23; e) in terms of an exemption under section 7(1)(b) or 24(6); or f) in the case of a protected area on land outside a State forest, with the consent of the

registered owner or by reason of another right which allows the person concerned to do so, subject to the prohibition in section 7(1).

Implications for the Slang River low-level crossing: o No forest or trees that form part of a forest or forest association may be damaged or

destroyed without a permit. o Development that comes within 50 metres of forest must be closely monitored during

the construction phase. o No forest species were identified in the immediate area.

2.5 Species of Conservation Concern (SCC)

National Environmental Management: Biodiversity Act (No. 10 of 2004) The National Environmental Management: Biodiversity Act (No. 10 of 2004), (NEMBA) aims to establish national norms and standards for the management of biodiversity across all sectors and by different management authorities. Chapter 4, Part 2 of the Biodiversity Act provides for listing of species as threatened or protected. If a species is listed as threatened, it must be further classified as critically endangered, endangered or vulnerable. The Act defines these classes as follows:



Table 2.1: NEMBA classes and explanations

Critically endangered species Any indigenous species facing an extremely high risk of extinction in the wild in the immediate future.

Endangered species Any indigenous species facing a high risk of extinction in the wild in the near future, although it is not a critically endangered species.

Vulnerable species Any indigenous species facing an extremely high risk of extinction in the wild in the medium-term future; although it is not a critically endangered species or an endangered species.

Protected species

Any species which is of such high conservation value or national importance that it requires national protection‖. Species listed in this category will include, among others, species listed in terms of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Implications for the Slang River low-level crossing:

Any species identified during this site survey that are listed by this act will require permits prior to removal and prior to commencement of construction.

Endangered and Protected Flora in the 1974 Provincial Nature Conservation Ordinance (PNCO):

The Provincial Nature Conservation Ordinance (PNCO) protects the endangered and protected flora outside of protected areas. Species classified as Schedule 3 are endangered species. Species classified as schedule 4 are protected species. A permit is required for the removal or destruction of species on the PNCO list.

1976 List of Protected Trees (Government Gazette No. 9542 Schedule A) in the 1998 National Forest Act (NFA):

No person may cut, disturb, damage or destroy any protected tree or possess, collect, remove, transport, export, purchase, sell, donate or in any other manner acquire or dispose of any protected tree or any forest product derived from a protected tree, unless a permit has been acquired.

South African Red Data List The South African Red List of South African plants use the internationally recognised IUCN Red List Categories and Criteria to measure a species risk of extinction (Table 2.2). Since the Red List of South African plants are used widely for conservation practices throughout South Africa, this list has been modified to identify species that are at low risk of extinction but of high conservation importance. Table 2.2: South African Red Data List Categories (SANBI, 2013)

EXTINCT (EX)

A species is Extinct when there is no reasonable doubt that the last individual has died. Species should be classified as Extinct only once exhaustive surveys throughout the species' known range have failed to record an individual.

EXTINCT IN THE WILD (EW) A species is Extinct in the Wild when it is known to survive only in cultivation or as a naturalized population (or populations) well outside the past range.

REGIONALLY EXTINCT (RE) A species is Regionally Extinct when it is extinct within the region assessed (in this case South Africa), but wild populations can still be found in areas outside the region.

CRITICALLY ENDANGERED, POSSIBLY EXTINCT (CR PE)

Possibly Extinct is a special tag associated with the category Critically Endangered, indicating species that are highly likely to be extinct, but the exhaustive surveys required for classifying the species as Extinct



has not yet been completed. A small chance remains that such species may still be rediscovered.

CRITICALLY ENDANGERED (CR)

A species is Critically Endangered when the best available evidence indicates that it meets at least one of the five IUCN criteria for Critically Endangered, indicating that the species is facing an extremely high risk of extinction.

ENDANGERED (EN) A species is Endangered when the best available evidence indicates that it meets at least one of the five IUCN criteria for Endangered, indicating that the species is facing a very high risk of extinction.

VULNERABLE (VU) A species is Vulnerable when the best available evidence indicates that it meets at least one of the five IUCN criteria for Vulnerable, indicating that the species is facing a high risk of extinction.

NEAR THREATENED (NT) A species is Near Threatened when available evidence indicates that it nearly meets any of the IUCN criteria for Vulnerable, and is therefore likely to become at risk of extinction in the near future.

CRITICALLY RARE

A species is Critically Rare when it is known to occur at a single site, but is not exposed to any direct or plausible potential threat and does not otherwise qualify for a category of threat according to one of the five IUCN criteria.

RARE

A species is Rare when it meets at least one of four South African criteria for rarity, but is not exposed to any direct or plausible potential threat and does not qualify for a category of threat according to one of the five IUCN criteria.

RARE DECLINING

A species is Declining when it does not meet or nearly meet any of the five IUCN criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened, but there are threatening processes causing a continuing decline of the species.

LEAST CONCERN

A species is Least Concern when it has been evaluated against the IUCN criteria and does not qualify for any of the above categories. Species classified as Least Concern are considered at low risk of extinction. Widespread and abundant species are typically classified in this category.

DATA DEFICIENT – INSUFFICIENT INFORMATION (DDD)

A species is DDD when there is inadequate information to make an assessment of its risk of extinction, but the species is well defined. Listing of species in this category indicates that more information is required and that future research could show that a threatened classification is appropriate.

DATA DEFICIENT – TAXONOMICALLY PROBLEMATIC (DDT)

A species is DDT when taxonomic problems hinder the distribution range and habitat from being well defined, so that an assessment of risk of extinction is not possible.

NOT EVALUATED (NE)

A species is Not Evaluated when it has not been evaluated against the criteria. The national Red List of South African plants is a comprehensive assessment of all South African indigenous plants, and therefore all species are assessed and given a national Red List status. However, some species included in Plants of southern Africa: an online checklist, are species that do not qualify for national listing because they are naturalized exotics, hybrids (natural or cultivated), or synonyms. These species are given the status Not Evaluated and the reasons why they have not been assessed are included in the assessment justification.



3 DESCRIPTION OF THE PHYSICAL ENVIRONMENT

3.1 Climate The Eastern Cape has a complex climate. There are wide variations in temperature, rainfall and wind patterns, mainly as a result of movements of air masses, altitude, mountain orientation and the proximity of the Indian Ocean. The area is subject to strong winds from the west and west-south-west (41% combined frequency) all year round, and east (15%) from October through to March. These winds occur mainly throughout the day and may generate a significant amount of fugitive dust. Diurnal variations in the wind regime occur which are due to the influence of land-sea breeze circulation on the airflow of the region. The closest town to the proposed crossing, with weather data is Oyster Bay. The climate in Oyster Bay is mild, and generally warm and temperate. Rainfall is abundant throughout the year (approximately 760 mm annually). Summers are warm (highest maximum temperature of 27°C) and winters cool (lowest minimum temperature of 8°C) with a relatively narrow annual temperature range. The average annual temperature in Oyster Bay is 16.7 °C. The variation in temperatures throughout the year is approximately 5.8 °C (http://en.climate-data.org/location/189667/).

3.2 Geology and Soils (Source: www.geoscience.org.za, AGIS 2015) The geology of the proposed project falls within the Cape Supergroup and is comprised of the Bokkelveld and Table Mountain groups and in the Ceres and Nardouw Subgroups respectively (Figure 3.1.). The Cape Supergroup constitutes the major part of the Cape Fold Belt. This is a belt of deformed rocks that runs approximately west-east across the southern most parts South Africa, from the Western Cape, through Grahamstown, entering the sea to the east, near the mouth of the Fish River (east of Kleinmond) (Buttner et al, 2015). The Bokkelveld Group consists of dark-grey shales with intervening sandstone units. This group contains a large variety of invertebrate fossils and is subdivided into a lower Ceres Subgroup, characterised by marine invertebrate fossils and lateral continuity of its six formations, and an upper Traka Subgroup consisting of three formations in the Eastern Cape. The project area falls within the Ceres Subgroup. This subgroup consists of alternating dark grey mudrock, lithozones and dark, very fine grained muddy sandstone. The Table Mountain Group is carved out of rocks of the Cape Supergroup. This Group mainly comprises of six formations and is predominantly a medium-grained arenaceous succession. The uppermost three formations together constitute the Nardouw Subgroup. Soils of the project area are classified as wetland soils, greyish and sandy in texture with poor drainage (AGIS, 2015).

https://en.wikipedia.org/wiki/Temperature

http://en.climate-data.org/location/189667/

http://en.climate-data.org/location/189667/

http://www.geoscience.org.za/



Figure 3.1: Map indicating the geology of the proposed

3.3 Topography The Eastern Cape Province contains a wide variety of landscapes, from the stark Karoo (the semi-desert region of the central interior) to mountain ranges and gentle hills rolling down to the sea. The mountainous area on the northern border forms part of the Great Escarpment. Another part of the escarpment lies just north of Bhisho, Somerset East and Graaff-Reinet. In the south of the province the Cape Folded Mountains start between East London and Port Elizabeth and continue westward into the Western Cape. Like KwaZulu-Natal, the Eastern Cape is characterised by a large number of short, deeply incised rivers flowing parallel to each other. The topography of the NMBM area can be described as a combination of flat, seaward sloping coastal plains averaging 75 m above mean sea level to high, mountain terrains in the north-western parts (Arcus GIBB, 2011). The topography of the project area is dominated by plains with open low hills and ridges. The Slang River crosses the project area in a north to south direction where it flows towards the ocean.

3.4 Socio-economic aspects and Current land use The major economic drivers in the region include agriculture, hunting, forestry and fishing, accounting for 12.3% of employment within the Kouga Local Municipality (WSDP, 2007; National Water Resource Strategy, 2004). Tourism and agricultural are the main primary sectors, with tourism accounting for 35.76% of the overall economy. Water resource requirements are significant in both the tourism and agricultural sectors. According to the National Water Resource Strategy (2004), the Tsitsikamma sub-area water requirements include approximately 11million m3/a for irrigation usage, 5million m3/a for urban usage, 5million m3/a for afforestation and 1million m3/a for rural usage. Water bodies are furthermore of importance in the tourism sector with regard to aesthetics as water bodies, such as rivers, lagoons, wetlands and the ocean, are main tourist



attractions in the area. These water systems additionally support recreational, subsistence and commercial fishing activities. The project area is currently zoned as Agricultural land and is not irrigated (AGIS, 2015). Dominant agricultural activities include small scale farming (Dairy farms) and medium cultivation. The agricultural practices predominantly undertaken in the area include irrigation of arable crops, dairy farming, sheep or mohair farming and cattle grazing. National Landover spatial tools also indicate that the surrounding area is classified as Thicket and Bushland (Figure 3.2) which was not confirmed during the site visit as the entire area has been transformed by Agriculture and very limited if any indigenous or intact vegetation exist (Plate 3.1). The irrigated cropland and the grazing pastures contribute significantly to the demand for water and thus to ground and surface water abstractions.

Figure 3.2: Landcover classification of the proposed project area in relation to the surrounding area.



Plate 3.1: Current land use of the proposed project area dominated by Dairy Farming.



4 DESCRIPTION OF THE ECOLOGICAL ENVIRONMENT The study site and surrounding areas were described using a two-phased approach. A desktop study of the site was undertaken, with reference to the current biodiversity and spatial plans and programmes, followed by a site visit which was conducted in order to further determine the present ecological state (PES) of the aquatic environment and to obtain photographic evidence. The desktop assessment made reference to published literature on the ecology of the area and various relevant programmes and plans, including:

The Eastern Cape Biodiversity Conservation Plan (ECBCP) (2007).

The National Freshwater Ecosystem Priority Areas Programme (2011).

South African National Biodiversity Institute, vegetation classification (Mucina and Rutherford, 2006)

Subtropical Thicket Ecosystem Protection (STEP) Programme (2006)

4.1 Aquatic Environment 4.1.1 Water Management Area (WMA) There are nine (9) water management areas (WMAs) established and defined within the Government Notice No. 35517 of 27 July 2012, according to the National Water Act (NWA), 1998 (Act No. 36 of 1998) and supported by the National Environmental Management Act (NEMA), 1998 (No. 107 of 1998). The National Water Resource Strategy (NWRS) is the implementation strategy for the National Water Act and further provides the framework, policies, objectives, guidelines, procedures and institutional arrangements for water resource management in South Africa. The NWRS emphases the need to protect, conserve, efficiently manage and control these water resources to ensure appropriate usage and development. Following the reduction of WMAs from nineteen (19) to (9) in July 2012, the NWRS have begun the process to establish catchment management agencies for these nine (9) WMAs, each responsible for developing and implementing a catchment management strategy for their jurisdiction. The study area falls within the Mzimvubu to Tsitsikamma WMA, which incorporates two former Water Management Areas, namely WMA 12 - Mzimvubu to Kei (referred to as the eastern half of the new WMA) and WMA 15 – Fish to Tsitsikamma (referred to as the western half of the new WMA). The Slang River falls within the Tsitsikamma sub-area of the former Fish to Tsitsikamma (WMA). There are three conservation areas of importance within the WMA, namely the Addo Elephant National Park, the Mountain Zebra National Park and the Alexandria Dune Field. The open Great Fish River estuary is additionally of ecological importance. The western half of the Mzimvubu to Tsitsikamma WMA is supported by the large transfer of water from the Upper Orange WMS into the catchments of the Fish and Sundays Rivers due to the natural high salinity of these water areas. This transfer equates to almost ten times the local surface water yield within these sub-areas and thus requires the implementation of efficient water resource management. Approximately 96% of the water usage within these sub-areas is as a result of irrigation, which is thus essentially sourced from the Orange River. These sub-areas experience large distribution losses due to the unlined irrigation canals that contribute to large volumes of irrigation return flow reaching the main streams and further deteriorating water quality in these water systems. Additionally, there is evidence of localised over-exploitation of groundwater water resources in the area due to extensive utilisation in supply towns and rural areas. The natural mean annual runoff (MAR) of the sub-area (former WMA-15) is 544mm while the ecological Reserve is 107million m3/a. The available yields in the Tsitsikamma sub-area, based on the yields of 2000, comprises of 41million m3/a of surface water and 6million m3/a of ground water. These measurements allow for impacts on yield of the Reserve, river losses, alien vegetation, rain-fed sugar cane and urban runoff. The usable return flow of the area is 1 million m3/a on irrigation and 1 million m3/a for urban uses. The total local yield is 49 million m3/a, which is relatively low in comparison to the Sundays and Gamtoos sub-areas.



The total local water requirements for the year 2000 were 22 million m3/a, with a transfer balance of 0 meaning the transfers in and out of the sub-area were balanced with the water requirements. It is estimated that there will be no potential for development of water resources for the Tsitsikamma sub-area in the year 2025. The base scenario reconciliation of water requirements and water availability indicate that the local yield is estimated at 52 million m3/a, while the local requirements and the outward transfers are predicted to be 24 million m3/a and 22 million m3/a, respectively, leaving a balance of 6 million m3/a. The high scenario indicated a local yield of 52 million m3/a, local requirements of 27 million m3/a and outward transfers of 22 million m3/a, leaving a balance of 3 million m3/a (National Water Resource Strategy, 2004). The fundamental water resources management strategies for the Fish to Tsitsikamma WMA are therefore to:

Efficiently use transferred water and proper management of water quality;

Achieve improved irrigation efficiencies and maximise the benefits; and

Ensure sufficient future water supplies to the Port Elizabeth area. It is essential to implement water resource management strategies, promote conservation and ensure restoration relating to any water body, including the Slang River and Estuary regardless of the size of these systems. 4.1.2 Background to the Slang River within the project area There are four main rivers in the Kouga Local Municipality, namely the Kromme, Seekoei, Kabeljouws and Gamtoos. The Kromme River, the Gamtoos River and ground water aquifers are the main sources of water supply in the area. There are various wetland areas that are of extreme sensitivity to disturbances such as agricultural or development activities. These wetlands characterise high species diversity and support natural water purification and flood retention. The Slang River is approximately 4km long flowing from Humandorp to Slangbaai, where the river mouth meets the Indian Ocean (Figure 4.1). The Slang River falls within the Fish to Tsitsikamma Water Management Area, which is then divided into six sub-areas. The Slang River is located in the Tsitsikamma sub-area and, more specifically, within the K80F quaternary catchment (Figure 4.2). The K80F catchment receives approximately 769 mm of rainfall per annum, with higher rainfall in the spring and autumn months. The mean annual runoff (MAR) of the catchment area is approximately 62mm (WSDP, 2007). The catchment area comprises of an inter-granular aquifer with medium yields and a relatively high recharge rate. According to the Reconciliation Strategy for Oyster Bay (2007) the groundwater availability of the quaternary catchment is 2.756million m3/a, although much of this groundwater is abstracted for uses by agricultural or urban activities. The catchment is characterised by underlying Table Mountain Group outcrops lying parallel to the coast, encompassing layers of quartzitic sandstone and shale of Skurweberg, Goudini, Cedarberg and Penisula formations. The undulating terrain comprises quaternary deposits and Nanaga aeolianite, a solid rock formed by marine deposits (National Water Resource Strategy, 2004; Umvoto Africa, 2011; WSDP, 2007).



4.1.3 The Slang Estuary The Slang Estuary, one of approximately 256 functioning estuaries in South Africa, is classified by Bornman (2013) and Cooper et al. (2000) as a small, temporarily open/closed system (TOCE), or otherwise an intermittently open estuary (IOE), with a warm to temperate biogeography. Cooper et al. (2000) describes the Slang Estuary to have poor species richness, limited ichthyofauna diversity, relatively low accounts of species assemblages and low abundance of species relative to other estuaries in South Africa. Bornman (2013), on the contrary, refers to the high diversity and biomass of estuarine specific fauna and flora of the Slang Estuary, relative to its size. The Slang Estuary is mostly perched and only becomes tidal after a relatively significant flood, after which the sand builds up at the river mouth over the course of a few days and the estuary is once again perched. The dynamics of the mouth are vital in controlling the ecological dynamics of estuaries. The mouth status (open or closed) is reliant on the water balance and the river inflow. During dry conditions, the estuary is unlikely to reach the sea, however during high levels of rainfall and freshwater runoff, the water levels rise. The estuary may be dominated by river conditions during breaching when flow rates exceed mean annual runoff (MAR). Conversely, once freshwater inflows decline below that of MAR, the estuarine open phase can occur with tidal exchanges and seawater inflows. Bornman (2013) highlights the significant reduction of the freshwater flow to the Slang Estuary due to illegal impoundments and abstractions from the estuary catchment. It was noted that the estuary did not reach the sea for more than two years during a dry climatic cycle, having substantial impacts on its ecosystem functioning. A reduction in the base flow and the river inflow that is required to continuously erode the encroaching dunes and wash the sand into the sea may result in the dunes advancing towards recreational areas. In the event of flooding, this poses major risks to safety and potentially causes damage to infrastructure. Further concerns for the estuary include the degradation caused by large-scale infestation of alien vegetation and the low water quality evident. The poor water quality may be due to a number of reasons, including untreated wastewater from agricultural activities causing eutrophication of the river and estuary, over-abstraction of water from the system and the lack of freshwater flowing into the estuary. The Slang Estuary is described to have poor ecological status and is barely functional. Despite this the estuary still has a high diversity and biomass of estuarine specific fauna and flora relative to its size and thus remains an important system. Based on this Bornman (2013) thus indicated that it is of importance to conserve and restore the estuary to rehabilitate the ecosystem.



Figure 4.1: Map indicating the location of the project area including the identification of sensitive environments (Source: Africoast Engineers)



Figure 4.2: Map indicating the location of the project area in the relevant Water Management Area (Source: Africoast Engineers)



4.2 Terrestrial and Riparian environment The project area falls within the Fynbos Biome. The Fynbos Biome takes its name from the dominant vegetation in the region – fynbos (Mucina and Rutherford, 2006). This biome consists of three quite different, naturally fragmented vegetation types (fynbos, renosterveld and strandveld) that occur in the summer and winter rainfall areas. Fynbos comprises of species that are typically small-leaved, evergreen shrubs and that rely on fire for regeneration. This Biome is endemic to South Africa and occupies most of the Cape Fold Belt, the adjacent lowlands between mountains and the Atlantic Ocean in the west and south as well as between the mountains and the Indian Ocean in the south. 4.2.1 SANBI Vegetation Map Mucina and Rutherford (2006) developed the National Vegetation map as part of a South African National Biodiversity Institute (SANBI) funded project: ―It was compiled to provide floristically based vegetation units of South Africa, Lesotho and Swaziland at a greater level of detail than had been available before.‖ The map was developed using a wealth of data from several contributors and has allowed for the best national vegetation map to date, the last being that of Acocks developed over 50 years ago. The National Vegetation map informs finer scale bioregional plans such as STEP. This Vegmap project had two main aims:

―to determine the variation in and units of southern African vegetation based on the analysis and synthesis of data from vegetation studies throughout the region, and

to compile a vegetation map. The aim of the map was to accurately reflect the distribution and variation on the vegetation and indicate the relationship of the vegetation with the environment. For this reason the collective expertise of vegetation scientists from universities and state departments were harnessed to make this project as comprehensive as possible.‖

The map and accompanying book describes each vegetation type in detail, along with the most important species including endemic species and those that are biogeographically important. This is the most comprehensive data for vegetation types in South Africa. The Slang River Crossing is located within the Tsitsikamma Sandstone Fynbos (Figure 4.3) which is a medium dense, tall proteoid shrubland over a dense moderately tall, ericoid-leaved shrubland – mainly proteoid, restoid and ericoid fynbos, with fynbos thicket in wetter areas. Characteristic vegetation include endemic taxa such as Aspalathus teres subsp. thodei, Erica trachysantha, Erica zitzikammensis, Felicia tsitsikamae and Helichrysum outeniquense. Distribution of Tsitsikamma Sandstone Fynbos within the Eastern and Western Cape Provinces are limited to the Tsitsikamma Mountains from Uniondale to Cape St Francis, north of the Keurbooms River and south of Langkloof. The conservation status of this vegetation type is classified as ‗Vulnerable‘ and is listed as ‗poorly protected‘. The conservation target (percent of area) as set by the NSBA is 22%. At present about 40% has been statutorily conserved in the proposed Garden Route National Park (including Tsitsikamma and Soetkraal). Approximately 33% of Tsitsikamma Sandstone Fynbos has been transformed by cultivation and pine plantations.



Figure 4.3: National Vegetation Map illustrating the vegetation type found within the project area. 4.2.2 Subtropical Thicket Ecosystem Programme (STEP) The Subtropical Thicket Ecosystem Planning (STEP) Project aims to identify priority areas that would ensure the long-term conservation of the subtropical thicket biome and to ensure that the conservation of this biome is considered in the policies and practices of the private and public sector that are responsible for land-use planning and the management of natural resources in the region (Pierce et al. 2005). STEP looked specifically at the thicket biome and has provided a finer scale map of the project area than the Mucina and Rutherford map explaining why the two vegetation maps look slightly different. According to STEP, only Humansdorp Grassy Fynbos (classified as Least Threatened) occurs in the project area (Figure 4.5). This vegetation type is grassy throughout and grows mainly on stony soils. Proteas (Protea neriifolia) are rare but conebushes (Leucadendron salignum) and ericas (Erica glandulosa) are common. According to STEP, Least Threatened ecosystems (previously called ―Currently Not Vulnerable‖) are ecosystems which cover most of their original extent and which are mostly intact, healthy and functioning. Depending on other factors such as connectivity with surrounding vegetation, Least Threatened land can withstand some loss of natural area through disturbance or development. From a Spatial planning (forward planning – Spatial Development Frameworks (SDF)) point of view, for Least Threatened vegetation, STEP presents two restrictions and gives examples of opportunities. These spatial planning restrictions are as follows: 1) Proposed disturbance or developments should preferably take place on portions which have already undergone disturbance or impacts rather than on portions that are undisturbed. 2) In general, Least Threatened land can withstand some loss of/disturbance to natural areas through human activities and developments.



Depending on constraints (such as avoidance of spoiling scenery or wilderness, or infra-structure limitations), Least Threatened land can withstand some loss of, or disturbance to, natural areas. Within the constraints, this class may be suitable for a wide range of activities (e.g. extensive urban development, cultivation, tourist accommodation, ecotourism, game faming). Proposed disturbance or developments should preferably take place on portions which have already undergone disturbance or impacts rather than on portions that are undisturbed or unspoilt by impacts. It should be noted that even though the area is considered to be Least Threatened in its entirety by STEP, the site has been isolated by various forms of development and agricultural practices. Thus the area is isolated due to fragmentation and limited opportunities for connectivity exist. In addition to this, the area has been heavily impacted on by anthopogenic activities, such as the building of dams, clearing and agricultural activities which has resulted in an increase in alien invasive species to the extent virtually the entire project area and immediate surrounding area is transformed and dominated by alien species such as Acacia saligna. The riparian area is dominated by Phragmites australis (Common reed) and Prionium serratum (Palmiet).

Figure 4.4: Regional Vegetation Map illustrating the vegetation type found within the project area as classified by STEP (2006).



Figure 4.5: Transformed areas as classified by STEP (2006). 4.2.3 Eastern Cape Biodiversity Conservation Plan (ECBCP) The ECBCP is a first attempt at detailed, low-level conservation mapping for land-use planning purposes. Specifically, the aims of the Plan were to map critical biodiversity areas through a systematic conservation planning process. The current biodiversity plan includes the mapping of priority aquatic features, land-use pressures, and critical biodiversity areas and develops guidelines for land and resource-use planning and decision-making. The main outputs of the ECBCP are ―critical biodiversity areas‖ or CBAs, which are allocated the following management categories:

1. CBA 1 = Maintain in a natural state 2. CBA 2 = Maintain in a near-natural state

The ECBCP maps CBAs based on extensive biological data and input from key stakeholders. The ECBCP, although mapped at a finer scale than the National Spatial Biodiversity Assessment (Driver et al., 2005) is still, for the large part, inaccurate and ―coarse‖. Therefore it is imperative that the status of the environment, for any proposed development MUST first be verified before the management recommendations associated with the ECBCP are considered (Berliner and Desmet, 2007). It is also important to note that in absence of any other biodiversity plan, ECBCP has not yet been adopted by the Provincial Department of Economic Development and Environmental Affairs (DEDEAT) as a strategic biodiversity plan for the Eastern Cape. In terms of aquatic CBAs, the K80F catchment is not categorised as a CBA 1 or CBA 2 area. The ECBCP map (Figure 4.6 and Figure 4.7) for the project area shows that the project area is categorised as a Functional Landscape and BLMC 4. The site is in an area that is classified into a BLMC 4 category (Transformed landscape – Cultivated Land). This implies that the site should be managed for sustainable development. The recommended land uses as outlined by the ECBCP (2007) include game farming, communal livestock, dry land cropping, irrigated cropping, dairy



farming, timber, settlements and conservation. The landuse of the project area will not change and will remain rural. The ECBCP (2007) also recommends that any proposed development near wetlands (rivers, marshes and vleis) should be carefully assessed to prevent further damage to them. Open space areas need to be created where SCC, that have little chance of recovery, occurs. Rehabilitation should occur in such a manner that connectivity between open space areas are improved.

Figure 4.6: Critical Biodiversity Areas (CBA) as classified by ECBCP (2007).



KLIPDRIFRIVIER

SLANGRIVIER

Klipdrifrivier

Sla

ng

rivie

r

OesterbaaiOesterbaaiOesterbaaiOesterbaaiOesterbaaiOesterbaaiOesterbaaiOesterbaaiOesterbaai

THYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITETHYSPUNT NATURAL HERITAGE SITE

STATE LANDSTATE LANDSTATE LANDSTATE LANDSTATE LANDSTATE LANDSTATE LANDSTATE LANDSTATE LAND

F732/17F732/5

F737/0

F732/11 F740/0

F735/5F732/25 F732/14

F732/21

F732/13F732/12

F733/4

F738/3

F732/23

F733/10

F735/12

F733/5

F735/10

F732/15

F732/3

F735/11

F735/9

F733/6

F734/1

F732/16

F732/7

F734/0 F735/17

F1111111/0

F727/5

F736/9

F736/8

Terrestrial Biodiversity

Land Management Classes

BLMC1: maintain natural state

BLMC2: maintain near natural state

BLMC3: functional landscapes

BLMC4: towns & settlements

BLMC4: cultivated land

BLMC4: plantation/woodlots

Inland water

Degraded

Figure 4.7: BLMC Land management classes as classified by ECBCP (2007).

Proposed low-level crossing



4.2.4 Present Ecological State (PES) of the Slang River and associated wetlands

Introduction The NFEPA programme provides strategic spatial priorities for conserving South Africa‘s freshwater ecosystems and supports sustainable use of water resources. These priority areas are called Freshwater Ecosystem Priority Areas, or FEPAs. Wetland ecosystem types were used by NFEPA for representing natural examples of the diversity of wetland ecosystem types across South Africa. Wetlands of the same ecosystem type are expected to share similar functionality and ecological characteristics. The biodiversity target for freshwater ecosystems in South Africa is 20%, which means that we should keep at least 20% of each wetland ecosystem type in a natural or near-natural condition. This serves to conserve many common species and communities, and the habitats in which they evolve. Information used to classify wetlands as FEPAs included:

Ramsar status;

Known threatened frog and waterbird occurrences; and

Expert knowledge on biodiversity importance. There is a natural channelled valley-bottom wetland which extends on both the north and south sides of the proposed crossing upgrade. According to NFEPA a moderately modified ‗natural‘ wetland is located north of the crossing. This wetland stems from hillslope seepage linked to a stream which originates at two dams upstream (NFEPA classified this as artificial and heavily modified). It was confirmed during the site visit that the wetlands in close proximity to the site as discussed are substantially transformed. The Slang River was not included in the NSBA or the NFEPA programmes. However, the Department of Water and Sanitation included the Slang River sub-quaternary in their PESEIS Desktop Assessment (2014). The Present Ecological State (PES) is classified as category D, an ecosystem that has experienced large changes in ecosystem processes and relatively significant loss of natural habitat and biota. The Slang River is therefore largely modified. The level of disturbance is relatively high with multiple disturbances associated with socio-economic development. The Slang River (as an ecological process area) is of moderate ecological importance and has high ecological sensitivity. However, the river shows signs of considerable reduction in flow due to impoundments for irrigation created upstream and downstream of the project area. Algal growth in the river is evident mainly due to increased nutrients as a result from runoff from the surrounding agricultural areas. Erosion along the river bank is also evident which has resulted in an increase in sediment deposition and subsequently a reduction in the flow of the river. With this in mind, the impacts associated with the development of the collapsed causeway could be considered of low significance, provided mitigation measures are implemented and the construction is restricted to the project area and does not impede into adjacent aquatic or riverine systems. Table 4.1 summarises the status of the Slang River and the surrounding quaternary catchment area.



Table 4.1: Present Ecological State (PES) of the Slang River ASPECT STATUS SOURCE

Present Ecological State Category D DWS, 2014

Ecological Importance Moderate DWS, 2014

Ecological Sensitivity High DWS, 2014

Aquatic CBA No ECBCP, 2007

Terrestrial CBA No ECBCP, 2007

River status NOT FEPA NFEPA, 2011/2014

Wetland status NOT FEPA NFEPA, 2011/2014

Vegetation type Tsitsikamma Sandstone Fynbos Mucina and Rutherford, 2006/2012

STEP Classification Humansdorp grassy fynbos STEP, 2006

4.3 Site survey: description of vegetation/land cover 4.3.1 Riparian Vegetation The entire Riparian area within the project area shows evidence of disturbance and transformation. Impoundments for irrigation created upstream and downstream of the project area have resulted in the reduction in flow of the river and erosion along the river bank has resulted in an increase in sediment deposition, further adding to the reduction in the flow of the river. The Riparian vegetation is dominated by alien vegetation and weeds to the south of the road (Plate 4.1 – Plate 4.3). Dominant species include Acacia saligna, Cestrum laevigatum, Pennisetum clandestinum and Chenopodium album (See table 4.3 and 4.4 below). The section of river to the north of the road (Plate 4.4 – Plate 4.6) is dominated by algal growth as a result of increased nutrients from the runoff from the surrounding agricultural areas. The river as it runs underneath the low-level crossing is currently not flowing but rather trickling. This could either be as a result of debris from the collapsed bridge that obstructing the flow of the river or due to the time of the site survey which was conducted in the dry season. Species to the north of the site include Centella asiatica, Phragmites australis and Prionium serratum.



Plate 4.1: Image illustrating sedimentation and alien vegetation to the south of the road.



Plate 4.2: Image illustrating debris from collapsed river crossing and alien vegetation to the south of the road.

Plate 4.3: Image illustrating reduction in flow to the south of the road.



Plate 4.4: Image illustrating vegetation to the north of the road.



Plate 4.5: Image illustrating algal growth in the section of river to the north of the road.

Plate 4.6: Image illustrating algal growth and reduction of flow to the north of the road.



4.4 Floristics 4.4.1 Species of Conservation Concern Confirmed Species of Conservation Concern have been identified from the site visit and are listed below. These species have been identified as occurring on site and thus are given confirmed status. It is likely that more SCC will be found on site during the construction phase of the development, should it go ahead. The species list from the site survey was assessed against the South African Red Data List, the National Environmental Management Biodiversity Act (NEM:BA) list of protected species, DAFF‘s list of protected tree species and the Eastern Cape PNCO. A total of twenty four (24) species were identified within the project area. Twelve (12) of these species were identified as species of conservation concern listed on the South African Red Data and is classified as species of ―Least Concern‖ and one (1) species as declining. None of the identified species are protected in the Eastern Cape PNCO list or on the NEM:BA list. No protected tree species were recorded to occur within the project area. Table 4.2: Species recorded on site. Those recorded in the Red data list, PNCO, CITES, NEMBA and CARA has been classified according to each list and discussed below the table.

Red Data List (Critically Endangered)

Red Data List (Endangered)

Red Data List (Vulnerable)

Red Data List (Least Concern)

Red Data List (Near-threatened)

Red Data List (Declining)

Protected and Endangered Plants in terms of the Provincial Nature and Environmental Conservation Ordinance (No 19 of 1974).

Protected Trees in terms of the Forest Act (Act No. 84 of 1998).



SCIENTIFIC SPECIE NAME

REDLIST

Acacia saligna (Port Jackson willow)

Alien Species

Amaranthus thunbergii (Thunberg's amaranth)

LC

Arctotheca calendula (Cape dandelion)

LC

Centella asiatica (Centella / Gotu kola)

LC

Cestrum laevigatum (Inkberry)

Alien Species

Chenopodium album (Lamb's quarters / goosefoot)

Not Evaluated

Conyza (Erigeron) bonariensis (Hairy Fleabane)

Not Evaluated

Cyperus textilis (Basket grass)

LC

Hydrocotyle americana (Water pennywort)

LC

Lemna gibba (Duckweed)

LC

Melilotus alba (Honey clover)

Not Evaluated

Pennisetum clandestinum (Kikuyu grass)

Alien Species

Persicaria attenuata (Smart weed)

LC

Phragmites australis (Common reed)

LC

Polygonum aviculare (Common knotgrass)

Not Evaluated

Prionium serratum (Palmiet)

Declining

Rumex crispus (Curly dock)

Not Evaluated

Senecio inaequidens (Narrow-leaved ragwort)

LC

Sonchus oleraceus (Sowthistle)

Not Evaluated

Sporobolus africanus (Parramatta grass)

LC

Stellaria media (Chickweed)

Alien Species

Stenotaphrum secundatum (Buffalo grass)

LC

Trifolium repens (White clover)

Not Evaluated

Typha capensis (Cape Bulrush)

LC



4.4.2 Alien Species The project area is dominated by alien species and weeds. Alien species present on site and their category according to the NEM:BA Alien and Invasive Species Regulations (published 1 August 2014) are presented below (Table 4.4). Table 4.3: Alien invasive species present on site

Species Category Comment

Acacia saligna 1b According to the National Environmental Management: Biodiversity Act, 2004 control and eradication of a listed invasive species must be carried out by means and methods appropriate for the species concerned and the environment in which it occurs. This must be done in a way that causes the least possible harm to the environment and surrounding biodiversity. The methods used to eradicate these species must also be directed at the offspring, propagating material and re-growth of invasive species in order to prevent such species from regenerating and re-establishing themselves.

Cestrum laevigatum 1b

Pennisetum clandestinum

a. 1b in Protected Areas and wetlands in which it does not already occur. b. Not listed elsewhere.

Stellaria media

a. 1 a Prince Edward Island. b. 1 b Marion Island. c. Not listed on mainland or other off-shore islands.

Acacia saligna is also classified as a Category 2 invader in the CARA list and Cestrum laevigatum as a Category 1 weed.



Plate 4.7: Acacia saligna visible in the riparian area to the south of the project area.



5 WETLAND DELINEATION AND ASSESSMENT

5.1 Approach The study site and surrounding areas were described using a two-phased approach. Firstly, a desktop assessment of the project area was conducted in terms of GIS data available. This included the consideration of:

» 1:50 000 vector maps of wetlands

» The National Wetland Classification System (NWCS)

» NFEPA database (2011/2014) Further to the above, a site visit was conducted on the 14th December 2015 in order to:

» Delineate any wetlands found onsite;

» Assess the wetland health; and

» Assess the current land-use. The findings of the site visit served to inform the impact identification process of the proposed development on the wetland habitats and to assist in determining how significant these impacts would be.

5.2 Wetland definition ―Wetland‖ is a name given to a variety of ecosystems ranging from rivers, springs, seeps and mires in upper catchments, to midland marshes, pans and floodplains, coastal lakes, mangrove swamps and estuaries at the bottom of a catchment. These ecosystems all share the common primary driver of water and its prolonged presence is a fundamental determinant of soil characteristics, vegetation and animal life (DWAF, 2005). The National Water Act (Act No. 36, 1998) defines wetlands 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.” Thus wetlands must have one or more of the following characteristics:

» Hydromorphic soils: characteristic soils of prolonged saturation;

» Hydrophytes, at least occasionally: highly saturated plants; and

» High water table: A high water table that results in saturation at or near the surface, leading to anaerobic conditions developing in the top 50cm of the soil.

Wetlands are formed from a combination of geology, hydrology and topography features. These landforms form in parts of a catchment where the movement of water is slowed down or obstructed, causing soil to become temporarily, seasonally or permanently waterlogged.

5.3 Wetland Importance South Africa is a Contracting Party to the Ramsar Convention on Wetlands and has thus committed itself to the intergovernmental treaty, which provides the framework for the national protection of wetlands and the resources they could provide. The Ramsar Convention is the only global environmental treaty that deals with a particular ecosystem. The treaty was adopted in the Iranian city of Ramsar in 1971 and the Convention's member countries cover all geographic regions of the planet. Wetland conservation in South Africa is now driven by SANBI under the requirements of the National Environmental Management Biodiversity Act (NEMBA, 10, 2004).



In natural capital terms, wetlands may be seen as a significant economic investment. This monetary value is rooted to the fact that the primary tasks of a wetland are to process water and regulate runoff. This is important as the South African economy is heavily dependent on water and yet the climatic variability of the country has meant that for the most part rainfall occurs as intermittent, high intensity storms. The inherent value of wetlands is that they protect and regulate this water source by acting like sponges, soaking up water during flood events and releasing it during dry periods (DWAF, 2005). By regulating water flows during floods, wetlands may reduce flood damage and help prevent soil erosion. As natural filters wetlands help to purify water by trapping pollutants, heavy metals and disease causing organisms. The most common ecosystem services provided by wetlands are:

» Improved water quality

» Flood attenuation

» Sediment trapping

» Reduce number of water borne diseases

» Herbal medicine

» Water storage These ecosystem services are provided at very little cost but with significant payback for the South African economy. Despite being classified as the third most significant life support system on earth (IUCN, 1980), wetlands are some of the most threatened habitats in the world today. Breen & Begg (1989) reported that more than 50% of the wetland inventory in South Africa had disappeared. The main issues have been draining wetlands for crops and pastures, poorly managed burning and grazing resulting in headcut and donga erosion, planting alien invasive vegetation, mining, pollution and urban development. These have been significant as they alter the natural flow of water within wetlands and as water is the driver of wetland formation, any such changes will subsequently be damaging. A buffer around a wetland is usually recommended in order to protect the wetland from development in the vicinity. Aside from the negative impacts of construction in the vicinity of a watercourse or wetland, a major impact that needs to be considered should be the geotechnical competence of soil which is often waterlogged and prone to flooding. Wetland soils are usually high in clay and prone to wet and dry periods, allowing for expansion and contraction of soils. The wetland and watercourse buffers are therefore also important with regards to the demarcation of areas that are not good to build on/in due to the high soil moisture content and unstable soils. Developing solutions to these problems would be expensive and may not be sustainable in the long term.

5.4 Tools available to define wetlands and watercourses 5.4.1 National Freshwater Ecosystem Priority Areas After several years of development and testing, a National Wetland Classification System (NWCS) was completed in 2013. The South African National Biodiversity Institute (SANBI), through its National Wetland Inventory project, initiated a collaborative process to develop a classification by which wetland habitat types with shared natural attributes can be grouped together. The classification system is intended to be used throughout the country for a number of different applications, with a view to provide wetland specialists, academics, government and other role players with a common language when distinguishing different types of wetlands for management and conservation purposes.



The National Wetland Inventory maps are provided by SANBI through National Freshwater Ecosystem Priority Area (NFEPA) wetland maps, which classify the major wetlands and waterbodies in the country at a coarse spatial scale. The classification was applied to the wetlands included in the inventory‘s National Wetland Map after extensive field testing throughout the country and through the National Freshwater Ecosystem Priority Areas (NFEPA) project. The system comprises a hierarchical classification process of defining a wetland based on the principles of the hydro-geomorphic (HGM) approach at higher levels, with structural features being included at the finer levels (SANBI, 2009). For the purposes of this study Version 4 of the NWCS was used as baseline information, as per SANBI‘s BGIS interactive tool. The NWCS uses hydrological and geomorphological traits to distinguish the direct factors that influence wetland function. This is presented as a 6 tiered structure with four spatially nested primary levels that are applied in a hierarchical manner between different wetland types on the basis of these direct factors (SANBI, 2009).

» Level 1: distinguishes between marine, estuarine and inland ecosystems based on the degree of connectivity the systems have with the ocean.

» Level 2: categorises the regional wetland setting using a combination of biophysical attributes at the landscape level.

» Level 3: assesses the topographical position of inland wetlands. Level 4 concerns the hydrogeomorphic (HGM) units as defined as follows:

Landform- considering the shape and localised setting of the wetland;

Hydrological characteristics- nature of water movement into, through and out of the wetland; and

Hydrodynamics- the direction and strength of flow through the wetland.

The HGM unit is considered the focal point for NWCS as the upper levels mean to classify the broad bio-geographical context for grouping functional wetland units at the HGM level, whilst the lower levels provide more descriptive detail. Important rivers are also classified according to the NFEPA rivers maps. These rivers are considered Freshwater Ecosystem Priority Areas (FEPAs). FEPAs are strategic spatial priorities for conserving freshwater ecosystems and supporting sustainable use of water resources. FEPAs are an essential part of an equitable and sustainable water resource strategy meaning that they need to stay in a good condition to manage and conserve freshwater ecosystems, and to protect water resources for human use. This means that the areas should be supported by good planning, decision-making and management to ensure that human use does not impact on the aquatic ecosystem. 5.4.2 WET-Health and Present Ecological State Incorporation of the HGM approach in this system is significant as it has been adopted throughout aquatic assessment with regard to Present Ecological State and WET-Health assessments. These systems can then be easily integrated using the HGM approach in-line with Eco-classification process of river and wetland reserve determinations used by the Department of Water and Sanitation (DWS). The Ecological Reserve of a river or wetland is used by DWS to assess the water resource allocations when assessing water use licence applications (WULAs).



The WET- ranges of tools were developed to assist those wishing to undertake wetland rehabilitation, in terms of current and future human activities in Environmental Impact Assessments (EIA) or the Present Ecological State (PES) of a wetland in an Ecological Reserve Determination (ERD). These tools were developed as part of a nine-year research programme on wetland management which was initiated in 2003 by the Water Research Commission (WRC) and a range of partners that examines wetland rehabilitation, wetland health and integrity and the sustainable use of wetlands (WRC Project No. K5/1408). As wetlands are formed under the influence of geology, hydrology and topography it is necessary to note these features when delineating a wetland.

» Geology: geology influences the formation of a wetland by geological obstructions such as erosion resistant rock or impervious material close to the surface forcing groundwater to move close to or onto the soil surface.

» Hydrology: the water transfer mechanisms such as source, movement and exit are important features of a wetland.

» Topography: the topography of the landscape influences the likelihood of whether a wetland will form. For instance, under the right conditions wetlands may form in floodplains, valley bottoms, hillslopes, depressions and coastal flats.

A range of ‗hydro-geomorphic‘ types can be defined by considering the above features. Six HGM units are defined for South African inland wetlands (SANBI, 2009):

Figure 5.1: The HGM types for South African Inland wetlands (SANBI, 2009). The materials and methods of WET-Health Wetland Management Series (Macfarlane et al., 2007) establish the current ecological health of a wetland. This assessment defines wetland health ―as a measure of the deviation of wetlands structure and function from the wetland‘s natural reference condition‖ (Macfarlane et al., 2007).



A Level 1 Rapid Assessment would involve evaluating specific indicators pertaining to three categories of hydrological, geomorphological and vegetation health (Figure 5.2). The purposes of WET-Health are to aid users to understand the ecological condition of the wetland and identify the causes of degradation. The assessment criteria and information are specific to South Africa. The three categories (hydrological, geomorphological and vegetation) are assessed by taking into account the extent, intensity and magnitude of an impact which then produces a health score. Evaluation scores within each category are then combined to produce an overall impact of activities on the wetland system which corresponds to a Present State health category that provides an impact score scale of 1-6 and associated health category (ecological state) from A-F (Table 5.1), based on Kleynhans (1996, 1999). Such categories represent natural, largely natural, moderately modified, largely modified, extensively modified, and critically modified. The WET-Health Assessment also considers the likely trajectory of change based on the threats to or vulnerability of a wetland. Five categories of the Trajectory of Change include: large improvement, slight improvement, remains the same, slight decline and rapid decline. Overall health of the wetland is then presented by the calculated Present Ecological State scores and the most likely Trajectory of Change.



Figure 5.2: The steps involved in the WET-Health Level 1 rapid assessment (MacFarlane et al. 2007).

Step 1: Divide the Wetland into HGM units

Step 2: Assess Hydrological Health of the Wetland

» Step 2A: Evaluate changes to water input characteristics from the

catchment

» Step 2B: Evaluate changes to water distribution & retention within

wetland

» Step 2C: Determine the hydrological impact score of the HGM unit based

on integrating the assessments from Steps 2A & 2B

» Step 2D: Determine the overall Present Hydrological State of the

wetland based on integrating scores from individual HGM units

» Step 2E: Assess the anticipated Trajectory Of Change of the Wetland

Hydrology

Step 3: Assess Geomorphological Health

» Step 3A: Determine the Present Geomorphic State of the individual HGM

units

» Step 3B: Determine the overall Present Geomorphic State of the

wetland based on integrating scores from individual HGM units

» Step 3C: Assess the anticipated Trajectory Of Change of the geomorphology of the wetland

Step 4: Assess Vegetation Health of the wetland

» Step 4A: Familiarisation with the general structure and composition of

wetland vegetation in the area

» Step 4B: Identify and estimate the extent of disturbance classes

» Step 4C: Assess the changes to vegetation composition in each class

and integrate these for the overall HGM unit

» Step 4D: Determine the Present Vegetation State based on integrating

scores from individual HGM units

» Step 4E: Assess the anticipated Trajectory of Change of wetland

vegetation

Step 5: Represent the health scores for the overall wetland



Table 5.1: Description of A – F ecological categories based on Kleynhans (1996, 1999).

PES Description Combined impact score

PES Category Level of disturbance

Unmodified, natural. 0-0.9 A

Protected systems; relatively untouched by human hands; no discharges or impoundments allowed

Largely natural with few modifications. A slight change in ecosystem processes is discernable and a small loss of natural habitats and biota may have taken place.

1-1.9 B

Some human-related disturbance, but mostly of low impact potential

Moderately modified. A moderate change in ecosystem processes and loss of natural habitats has taken place but the natural habitat remains predominantly intact

2-3.9 C

Multiple disturbances associated with need for socio-economic development, e.g. impoundment, habitat modification and water quality degradation

Largely modified. A large change in ecosystem processes and loss of natural habitat and biota and has occurred.

4-5.9 D

The change in ecosystem processes and loss of natural habitat and biota is great but some remaining natural habitat features are still recognizable.

6-7.9 E

Often characterized by high human densities or extensive resource exploitation. Management intervention is needed to improve health, e.g. to restore flow patterns, river habitats or water quality

Modifications have reached a critical level and the ecosystem processes have been modified completely with an almost complete loss of natural habitat and biota.

8 - 10 F



6 PHYSICAL DESCRIPTION OF WETLAND AND AQUATIC ENVIRONMENT

6.1 Introduction Wetlands in the region were identified using:

» Satellite imagery (Google Earth); and

» NFEPA wetland shapefiles (Figure 6.1). The NFEPA classification combines the majority wetland vegetation group and level 4 of the NWCS, which describes the wetland landform, to produce a wetland type. These wetlands are also defined by the National Freshwater Ecosystem Priority Area (NFEPA). According to the National Vegetation Map Tsitsikamma Sandstone Fynbos is the only vegetation type said to occur in the Slang River Crossing project area (Mucina and Rutherford, 2006). According to STEP, which maps vegetation types at a finer scale, only Humansdorp Grassy Fynbos occurs in the project area. Both these vegetation types have been described in Chapter 4 of this report. As discussed in the previous chapters, neither of these wetlands are classified as FEPA wetlands.



Figure 6.1: National Freshwater Ecosystem Priority Areas (NFEPA) wetlands and wetland conditions (WETCON).

Description of NFEPA wetland conditions categories. C = Moderately modified-(Percentage natural land cover 25-75%) Z1 = Heavily to critically modified (wetland overlaps with a 1:50 000 ―artificial‖ inland water body) Z2 = Heavily to critically modified (Majority of wetland unit is classified as ―artificial‖ in the wetland delineation) Z3 = Heavily to critically modified (percentage natural land cover <25%)



6.2 Collection of site data Information on the project area and surrounding environments was gathered in a single site visit in December 2015. The data gathering process involved groundtruthing the area, delineating wetlands (Figure 6.2) and assessing the state of the environment. This included describing the following features:

» Possible impacts on the aquatic environment (Section 6); and

» Present Ecological State of the wetlands (using WET-Health) and watercourses.

6.3 Present Ecological State (PES) 6.3.1 Hydrology The mean annual precipitation of the area is 769 mm per annum, with a peak rainfall in the spring and autumn months (WSDP, 2007). These wetlands have been formed due to a change in the water table and surface water availability caused by damming at various locations along the Slang River, substantial agricultural development and land transformation. The alterations to the flow of the wetlands have had a large impact on the overall wetland health and regular water supply to the wetland for the past decade. These wetlands have naturalised over time and have developed a plant profile which indicate the development of wetlands. The hydrological integrity of the wetlands is largely driven by the artificial change in water availability. The hydrological health score was assessed as 4.5 with a PES category of D for the wetlands north of the crossing and 5.9 with a PES category D for the wetland south of the crossing. Both assessments indicate a largely altered hydrological regime.

DESCRIPTION IMPACT SCORE RANGE

HEALTH CATEGORY

No discernible modifications, or the modifications are of such a nature that they have no impact on the hydrological integrity.

0-0.9 A

Although identifiable, the impact of the modifications on the hydrological integrity is small.

1-1.9 B

The impact of the modifications on the hydrological integrity is clearly identifiable, but limited.

2-3.9 C

The impact of the modifications is clearly detrimental to the hydrological integrity. Approximately 50% of the hydrological integrity has been lost.

4-5.9 D

Modifications clearly have an adverse effect on the hydrological integrity. 51% to 79% of the hydrological integrity has been lost.

6-7.9 E

Modifications are so great that the hydrological functioning has been drastically altered. 80% or more of the hydrological integrity has been lost.

8 - 10 F

6.3.2 Geomorphology Increased run off from various roads, furrows and especially dams north of the crossing may result in greater sediment transport and deposition within the wetlands. Loss of vegetation cover due to grazing and burning may also have adverse impacts on the sedimentation within the wetlands on both sides of the low level crossing. The infilling for the Slang River crossing, along with the manipulation of the wetland channel has degraded the geomorphological health of the wetlands both North and South of the Slang River crossing.



The overall geomorphological health was assessed as 6 or a PES category of E for the wetlands north of the crossing and 4.5 or a PES category D for the wetland south of the crossing. Overall, the geomorphological health of the wetland was considered to be greatly modified.

DESCRIPTION IMPACT SCORE

PRESENT GEOMORPHIC

STATE CATEGORY

Unmodified, natural. 0-0.9 A

Largely natural with few modifications. A slight change in geomorphic processes is discernible but the system remains largely intact

1-1.9 B

Moderately modified. A moderate change in geomorphic processes has taken place but the system remains predominantly intact

2-3.9 C

Largely modified. A large change in geomorphic processes has occurred and the system is appreciably altered.

4-5.9 D

Greatly modified. The change in geomorphic processes is great but some features are still recognisable

6-7.9 E

Modifications have reached a critical level as geomorphic processes have been modified completely

8-10 F

6.3.3 Vegetation The area has been heavily impacted on by anthopogenic activities, such as the building of dams, clearing and agricultural activities which has resulted in an increase in alien invasive species to the extent that virtually the entire project area and immediate surrounding area has been transformed and dominated by alien species such as Port Jackson (Acacia saligna), Inkberry (Cestrum laevigatum), Kikuyu Grass (Pennisetum clandestinum), and Chickweed (Stellaria media). The riparian and wetland areas are dominated by the Common reed (Phragmites australis) and Palmiet (Prionium serratum) which is listed as ‗Declining‘ on the SA Red Data List. Other species identified within the wetland habitats include: Cape Bulrush (Typha capensis), Smart weed (Persicaria attenuata), Water pennywort (Hydrocotyle Americana), and the alien Chickweed (Stellaria media). Although there is considerable alien encroachment into both of the wetlands, the vegetation in the wetland north of the crossing is composed of more indigenous species and less aliens than the wetland south of the crossing. The vegetation composition south of the crossing has been largely altered. The impact score has been assessed as 3.5 or PES category C for the wetlands north of the crossing and 5.9 or PES category D for the wetland south of the low-level crossing.



DESCRIPTION IMPACT SCORE

PRESENT VEGETATION

STATE CATEGORY

Vegetation composition appears natural. 0-0.9 A

A very minor change to vegetation composition is evident at the site.

1 - 1.9 B

Vegetation composition has been moderately altered but introduced alien and/or ruderal species are still clearly less abundant than characteristic indigenous wetland species.

1 - 3.9 C

Vegetation composition has been largely altered and introduced alien and/or ruderal species occur in approximately equal abundance to the characteristic indigenous wetland species.

4 - 5.9 D

Vegetation composition has been substantially altered but some characteristic species remain, although the vegetation consists mainly of introduced, alien and/or ruderal species.

6 - 7.9 E

Vegetation composition has been totally or almost totally altered, and if any characteristic species still remain, their extent is very low.

8 - 10 F

6.3.4 Overall PES of Identified Wetlands According to the Department of Water and Sanitation (2014) the wetlands within the sub-quaternary catchment have been assigned a PES score of D, an EI score of ―moderate‖ and an ES score of ―moderate‖. The DWS reference for this catchment is 9127. The assessment and delineation identified extensive modification of the wetland system, especially the geomorphology north of the crossing. Major contributing factors include land transformation, grazing pressures, alien invasive vegetation, and the damming of the system at various locations along the Slang River. The wetlands north of the crossing (Hillslope seepage linked to a stream) had an overall score of:

PES score of D;

EI score of ―moderate‖; and

ES score of ―moderate‖. The wetland south of the crossing (Valley bottom with channel) has an overall score of:

PES score of D;

EI score of ―high‖; and

ES score of ―moderate‖. The EI score is rated as high due to the presence of Palmiet (Prionium serratum) which is listed as ‗Declining‘ on the SA Red List. Table 6.1 below illustrates the breakdown of the overall PES category ratings for both types of identified wetlands in proximity of the proposed low level bridge crossing. Figure 6.2 illustrates the groundtruthed and delineated boundaries of these wetland systems.



Table 6.1: Overall PES scores and ratings for the assessed wetlands.

HYDROLOGY GEOMORPHOLOGY VEGETATION

WETLAND (S) north of the crossing- Hillslope seepage linked to a stream

4.5 D 6 E 3.5 C

WETLAND (S) south of the crossing- Valley bottom with channel

5.9 D 4.5 D 5.9 D



Figure 6.2: Delineated wetlands and sensitive areas



6.3.5 Photographs of Wetlands Wetland (s) north of the crossing

Plate 6.1: Wetland features to the north of the project area.



Wetland (s) south of the crossing

Plate 6.2: Wetland features to the south of the project area.



7 BIODIVERSITY AND SENSITIVITY ASSESSMENT

7.1 Sensitivity analysis and site sensitivity Although all rivers and wetland areas and adjacent riverine/wetland vegetation are usually rated as areas of high sensitivity due to their present ecological state and their importance as an ecological process area (EPA), this rating cannot be assigned to this site. The area is highly degraded as a result of direct and indirect anthropogenic activities and has consequently been assigned a moderate to low sensitivity for the following reasons:

The River shows a reduction in flow due to impoundments upstream and downstream of the project area, mainly due to irrigation

There is a considerable amount of algal growth within the river (Plate 4.6 above) indicative of increased nutrients mainly from runoff from the surrounding agricultural areas.

A large amount of erosion is visible along the river banks which have resulted in an increase in sediment deposition during high rainfall and thus reduction in flow of the river.

The immediate area is dominated by alien vegetation (95%). The adjacent road and agricultural land has been classified as having a low sensitivity due to their degraded and transformed nature.



8 IMPACT IDENTIFICATION AND ASSESSMENT The study that has been undertaken provides the necessary information to assess the impacts of the project on the vegetation and the flora at various spatial and temporal scales. The individual impacts have been grouped together as a series of key environmental issues. All of the issues relate to the loss of the existing vegetation cover as a result of the activities and the redirection of the river which ultimately alters the flow, related to the project. At the spatial scale of the project area the impacts described below will not be considerable, but these need to be seen in the context of the project area as a whole or at a still larger spatial scale. The main issues identified with the existing impacts are discussed below for each phase of the project.

8.1 Planning and Design Phase Activities associated with the design and pre construction phase pertains mostly to a feasibility assessment which is done mostly at a desktop level. In some cases site visits need to take place but the impact of these visits are negligible, if any, e.g. photographs and field surveys, etc.

8.2 Construction phase This phase assesses the impacts associated with the construction of the low-level crossing. 8.2.1 Issue 1: Loss of Vegetation communities Natural plant communities are dynamic ecosystems that provide habitats that support all forms of life. Different types of plant communities (and habitats) exist in the project area, and these occur within and around the project area. The current condition of the vegetation communities in the project area can be described as mostly degraded and is surrounded by transformed agricultural land and dams created for irrigation. The current impacts on each plant community are assessed below. Impact 1a: Loss of Riparian vegetation Cause and Comment: The reconstruction of the low-level crossing will not result in the clearance or loss of indigenous riparian vegetation within the project area. It is anticipated that the removal of vegetation within the riparian area will be limited to alien vegetation occurring in the riparian zone and will be directly adjacent to the crossing that is to be reconstructed. A the reconstruction of the low-level crossing, the diversion of river flow as well construction occurring within 500 m of a wetland will require a Water Use Licence in terms of Section 21 (c) and (i) of the National Water Act, which has been applied for from the Department of Water and Sanitation (DWS). Under the no-go option the Riparian vegetation will be impacted on further by the current land use and due to the obstruction caused by the collapsed bridge and will eventually be lost. Significance Statement:

Effect Risk or

Likelihood

Overall

Significance Temporal Scale Spatial Scale Severity of Impact

Without Mitigation Short term Study Area Low Definite Low

With Mitigation Short term Localised Slight Definite Low

No-Go Option Long term Study Area Moderate Definite Moderate



Mitigation Measures:

The clearance of riparian vegetation should be kept to a minimum in order to reduce the possibility of soil erosion and consequent sedimentation of the Slang River.

Vegetation clearing and trampling should be avoided in areas demarcated as no-go areas.

Temporary infrastructure such as the site camp, laydown areas and storage areas must be placed outside the 32m buffer from the river.

Employees must be prohibited from making fires.

All alien vegetation within the development footprint should be removed from site and disposed of at a registered waste disposal site.

Only indigenous species should be used for rehabilitation purposes.

Impact 1b: Loss of Alien vegetation Cause and Comment: The reconstruction of the low-level crossing will result in the clearance of alien vegetation within the project area. This will be a positive impact as alien invasive species will be removed and subsequently this will also improve the flow of the river. Under the no-go option the existing alien vegetation will continue to encroach and eventually the banks of the river will be fully overgrown with alien species. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Short term Study Area Slight beneficial Definite Low +

With Mitigation Long term Study Area Moderate

beneficial Definite Moderate +

No-Go Option Long term Study Area Moderate Definite High


Alien species found in this area should be removed as part of the Alien management plan. 8.2.2 Issue 2: Loss of Biodiversity The reconstruction of the low-level crossing will not result in significant loss of biodiversity. Given that the footprint of the entire activity is relatively small and restricted to the road reserve and the area is infested with alien species, it is anticipated that the loss of biodiversity will be minimal and will not have a severe impact on the existing vegetation within the project area. The removal of the alien vegetation during clearing will have a positive impact on the remaining indigenous vegetation. Impact 2a: Loss of Floral Biodiversity (in general)

Cause and comment: As mentioned above, construction activities will result in some loss of biodiversity however, the removal of vegetation associated with the project (which has a small footprint) will be localised and confined to the project footprint. It is likely that the seedbank will be dominated by alien species based on the existing presence of alien vegetation on the river banks and thus rehabilitation may pose some challenges. Under the no-go option the loss of biodiversity will continue as agricultural activities and current encroachment of alien species will continuously impact on the indigenous vegetation and the River.



Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Short term Study Area Moderate Definite Moderate

With Mitigation Short term Localised Slight Definite Low

No-Go Option Long term Study Area Slight Probable Low


Refer to mitigation measures under Impact 1 above,

Prohibit all employees from harvesting plants;

Prohibit open fires;

An ECO must be employed to demarcate areas for use during construction, and to ensure that the construction activities remain within the designated area and that no unauthorised activities occur.

The disturbed area must be rehabilitated with indigenous plant species and seedlings of alien vegetation must be removed on a continuous basis.

Search and rescue must occur before construction starts. Species of conservation concern must be identified, rescued and stored for rehabilitation and applicable permits must be obtained prior to removal of such. The top layers of soil must be collected and stored for use in the rehabilitation plan. An area of the wetland which has been impacted by local land uses must be selected as a site for the rehabilitation of species of special concern collected during the search and rescue.

Impact 2b: Loss of Plant Species of Conservation Concern Cause and Comment: A total of twenty four (24) species were identified within the project area. Twelve (12) of these species were listed as least concern on the South African Red Data and one (1) species as declining. None of the identified species are listed on the Eastern Cape PNCO list or on the NEM:BA list. No protected tree species were recorded within the project area. There may be a number of additional species of conservation concern that will be found on site during construction that were not observed during this study. Under the no-go option this area may lose the few species of conservation concern that are presently found on the area. Alien invasive species compete with the indigenous plant species and grazing can also negatively affect the species present in the area. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Permanent Study Area Moderate Probable Moderate

With Mitigation Permanent Localised Slight Probable Low

No-Go Option Long term Study Area Slight Unlikely Low


Refer to mitigation measures under impact 2a above.



8.2.3 Issue 3: Disruption of Ecosystem Function and Process The habitats that exist in the project area, together with those of the surrounding area that are linked, form part of a functional ecosystem. An ecosystem provides more than simply a ‗home‘ for a set of organisms, and is a functional system where biological and biophysical processes such as nutrient cycling, soil formation, reproduction, migration, competition, predation, succession, evolution and migration take place. Destruction or modification of habitats causes disruption of ecosystem function, and threatens the interplay of processes that ensure environmental health and the survival of individual species. This issue deals with a collection of complex ecological impacts that are almost impossible to predict with certainty, but which are nonetheless important. Impact 3a: Impacts on sensitive ecosystems in terms of erosion and sedimentation Cause and Comment: Erosion and sedimentation of the Slang River and associated habitats due to poor layout design of the low-level crossing or the mismanagement of the construction area may result in the indirect loss of vegetation as well as sedimentation and erosion. Under the no-go option, sedimentation and erosion of the river bank is already evident. In addition, debris and alien species are obstructing flow of the river. This will continue to get worse under the no-go scenario. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Short term Study Area Moderate Likely Moderate

With Mitigation Short term Localised Low Probable Low



Refer to mitigation measures outlined under impact 2;

Newly cleared and exposed areas must be promptly rehabilitated with indigenous vegetation to avoid soil erosion. Where necessary, temporary stabilization measures must be used until vegetation establishes;

Plan for the worst case, that is, for heavy rainfall and runoff events, or high winds.

Appropriate erosion control measures must be implemented and a monitoring programme established to ensure that no erosion is taking place. At the first sign of erosion the necessary remedial action must be taken.

Reasonable measures to limit erosion and sedimentation due to construction activities must be implemented and must comply with the measures outlined in the EMP as and when required.

Implement a storm water management plan.



Impact 3b: Impacts on sensitive ecosystems in terms of pollution Cause and Comment: Spills and leaks from vehicles and machinery during construction and during placement of fill material into the watercourse may further pollute the aquatic environment and will exacerbate the algal growth already present and the overall condition of the river. Under the no-go option pollution such as litter, debris from the collapsed bridge is already evident and will continue. In addition, the algal growth already present will continue to dominate the river north of the road due to agricultural runoff and lack of movement of the water. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Short term Study Area Slight Likely Moderate

With Mitigation Short term Localised Slight Probable Low



Establish a dedicated area for construction vehicles to refuel and where cement can be mixed. Vehicle re-fuelling, generators and cement mixing must only take place on impervious surfaces and/or on drip trays;

Spill kits must be available on site to clean up after accidental spills;

Ensure all construction machinery is in sound working order to prevent oil leaks.

Temporary chemical toilets should not be located within 32m from the Slang River.

All hazardous materials or materials that pose a risk of leading to contamination should be kept in locked containers and not within 32m of the river.

Impact 3c: Temporary diversion of river flow Cause and Comment: The reconstruction of the low-level causeway over the Slang River will require that stream flow be temporarily diverted. This could impact on aquatic invertebrates and herps (reptiles and amphibians) as well as result in the loss of vegetation in areas that become dry as a result of the river diversion. Under the no-go option the river is currently not flowing adequately due to debris blocking flow, alien vegetation that has overgrown the area and as a result of impoundments created upstream and downstream of the project area. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Short term Study Area Low Definite Moderate

With Mitigation Short term Study area Low Definite Moderate

No-Go Option Long term Study Area Low Definite Moderate




The diversion should be for the shortest time practically possible and should be reverted back to the pre-construction flow pattern as soon as construction in this area is complete.

8.2.4 Issue 4: Impacts on wetlands and wetland function Impact 4a: Physical destruction of wetland habitat Cause and Comment: The construction of the low level bridge within the immediate vicinity of the wetlands may result in the loss of wetland vegetation. The removal of vegetation from this particular area is of relatively low significance due to the poor PES rating of the wetlands. The ecological integrity of the wetlands is poor due to land use practices (stock grazing) and the upstream damming of the Slang River. Under the no-go option, agricultural practices and the anthropogenic manipulation of the river and wetlands will further restrict the natural functioning of the wetland system. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Long term Study area Moderate May occur Moderate

With Mitigation Permanent Localised Low May occur Low



Ensure that the construction footprint is limited to what is needed in order to reduce the amount of vegetation which would need to be cleared.

The indigenous wetland vegetation which is removed to make way for the crossing upgrade which requires construction should be moved to the seasonal / permanent zone of the nearby wetland area where noticeable damage has occurred in order to contribute towards the ecological state of the wetland system.

A storm water management plan must be implemented to ensure that the section of impacted wetland is not completely cut off from the rest of the wetland system.

Ensure that flow of water from the north of the construction area to the south is not impeded. Temporary diversion measures should be implemented.

Impact 4b: Sedimentation and erosion within the wetland system Cause and Comment: The construction of the low level crossing within the immediate vicinity of the wetland may lead to sedimentation and erosion. The removal of vegetation and top soil layers to prepare for the new crossing, as well as the new exposed surface area will leave large areas exposed to the elements (wind and rain), causing runoff of sediments (and associated erosion) into the wetland system. Sediments may smother benthic habitats within the wetland system and lead to changes in flow patterns, vegetation distribution and overall wetland functionality. Under the no-go option, agricultural practices and the anthropogenic manipulation of the river and wetlands will further restrict the natural functioning of the wetland system. Significance Statement:

Effect Risk or Overall



Temporal Scale Spatial Scale Severity of Impact Likelihood Significance

Without Mitigation Medium term Study area Moderate Likely Moderate

With Mitigation Short term Study area Low Likely Low



Ensure that the construction footprint is limited to what is needed in order to reduce the amount of vegetation which would need to be cleared.

The wetland vegetation which is removed to make way for the crossing upgrade which requires construction should be moved to the seasonal / permanent zone of the nearby wetland area where noticeable damage has occurred in order to contribute towards the ecological state of the wetland system.

A storm water management plan must be implemented to ensure that the section of impacted wetland is not completely cut off from the rest of the wetland system.

Silt fences must be erected immediately downstream of the construction area to limit the movement of silt and soil mobilized during construction.

The design of the bridge structure must take into account the direction and strength of the flow of the river, and ensure that measures to reduce scouring of the river bed and erosion of the banks in the vicinity of the bridge are incorporated.

8.3 Operational Phase This phase assesses the impacts associated with the operational phase of the facility.

8.3.1 Issue 4: Disruption of Ecosystem Function and Process Impact 4a: Invasion of alien plant species Cause and Comment: The removal of existing vegetation creates ‗open‘ habitats that will inevitably be colonised by pioneer plant species. While this is part of a natural process of regeneration, which would ultimately lead to the re-establishment of a secondary vegetation cover, it also favours the establishment of undesirable species in the area, such as Acacia saligna. These species colonise areas of disturbance and once established, they are typically very difficult to eradicate and can pose a threat to the neighbouring ecosystem. The project area has a number of alien species present and the seedbank is therefore likely to be full of seeds from these undesirable species. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Permanent Study Area Severe Definite Moderate

With Mitigation Long term Study Area Moderate

beneficial Probable Low +



Implement an Alien Management Plan.

Eradicate alien plants from the impacted area as they appear; and

Monitor the project area for any new growth of invasive plants.



Impact 4b: Reduction of erosion and sedimentation Cause and Comment: Currently vehicles are driving across a deteriorated and collapsed river crossing which is resulting in an increase in erosion on the river banks as well as sedimentation into the river and wetland system. When construction of the new low level crossing is complete these banks will need to be rehabilitated and stabilised. This will result in a reduction in sediment input to the river and wetlands which will improve the flow of the river and improve the ecological integrity of the river and wetland systems. Significance Statement:

Effect Risk or

Likelihood

Overall


Without Mitigation Long term Study Area Slight Probable Low +

With Mitigation Long term Study Area Moderate Definite Moderate +



Banks must be rehabilitated, including re-establishment of vegetation cover.

Continued maintenance of low-level bridge, i.e. removing debris from the culverts and repair of the approach embankments after period of heavy rainfall.

Existing tracks through the river must be cordoned off with a barrier once the bridge is complete to prevent the continued use of this area.

The wetland vegetation removed during construction must be replanted to contribute towards the ecological state of the wetland system.

8.4 Decommissioning Phase It is highly unlikely that the bridge would be decommissioned as it serves as a connecting route from Humansdorp and Oyster Bay. Potential impacts were therefore not assessed for the decommissioning or closure of the facility.

8.5 Cumulative Impacts No cumulative impacts were identified.



9 IMPACT STATEMENT, CONCLUSION & RECOMMENDATIONS

9.1 Conclusions The Department of Roads and Public Works intends to reconstruct the low-level crossing over the Slang River which was damaged and collapsed during a flood event in 2011. The surrounding land is farmland and is currently used for agricultural purposes. Associated impacts identified with the proposed low-level crossing were not deemed insurmountable. No high rated impacts were identified and all other impacts (pre-mitigation) are easily mitigated. Recommendations in chapter 6 in this report provide mitigation measures to reduce the severity of the impacts. Overall, it was determined that the identified ecological impacts associated with the facility can be affectively mitigated.

9.2 Current status The vegetation on the study site is mostly transformed and degraded. No pristine vegetation exists as a direct result of the current land use (e.g. agricultural practices) and the infestation of alien plant species. The most important and long term impact is likely to be the continued infestation of alien plant species. The flow in the Slang River has been reduced as a result of:

Over abstraction of water for irrigation;

The creation of dams upstream and downstream of the project area;

Siltation of the river due to erosion and increased runoff from the surrounding agricultural fields;

The infestation of water hungry alien species along the banks of the river which have increased the abstraction of water and resulted in a decrease in flow rate and

Debris from the collapsed bridge is currently exacerbating the problem. Algal growth is dominating the river to the north of the road. This is mainly as a result of the reduced flow rate as well as the increased nutrients from runoff (containing nonpoint-source pollutants such as fertilizer and pesticides) from the surrounding agricultural land. A number of negative effects can result if this condition persists such as an increase in rate of sedimentation, the development of anoxic conditions (low oxygen levels), the decrease in species diversity and overstimulation of algal growth and subsequently block sunlight that may be essential for biota as well as aquatic vegetation (Water Encyclopaedia, 2015). Although the low-level crossing is located in the area that would under pristine circumstances be identified as high sensitivity (as discussed in Chapter 5) the footprint associated with this infrastructure is small and required to improve the flow of the river as well as the functioning of the system. With careful management during the construction phase, the impacts are likely to be of low significance.

9.3 Comparison of impacts The impacts associated with the reconstruction of the low level crossing with and without mitigation measures have been assessed (Table 7.1). Due to the very nature of a footprint, many of the impacts can be reduced with effective management of the site as well as rehabilitation after construction. It is essential that areas of high sensitivity are avoided where feasible. Alien invasive species should be managed effectively to prevent further impacts on the project area. Impacts associated with the Operational Phase are associated with impacts that cause erosion and sedimentation and increase the infestation of alien species.



Overall, the impacts of the development will be low negative after mitigation measures. Positive impacts include the active management of the alien vegetation on the site and the reduction in siltation in the river and controlling the erosion of the river banks. Table 9.1: Summary of impacts associated with the low level crossing pre and post mitigation. The no-go alternative has also been included for comparative purposes.

IMPACTS WITHOUT

MITIGATION WITH MITIGATION NO-GO

CONSTRUCTION PHASE

Loss of Riparian vegetation Low Low Moderate

Loss of Alien vegetation Low + Moderate + High

Loss of floral biodiversity (general)

Moderate Low Low

Loss of SCC Moderate Low Low

Impacts on sensitive ecosystems in terms of erosion and sedimentation

Moderate Low High

Impacts on sensitive ecosystems in terms of pollution


Temporary diversion of stream flow

Moderate Moderate Moderate

Physical destruction of wetland habitat

Moderate Low High

Sedimentation and erosion within the wetland system


OPERATIONAL PHASE

Invasion of alien plant species Moderate Low + High

Reduction of erosion and sedimentation

Low + Moderate + High

9.4 Invasion of alien species Any form of disturbance to the natural vegetation provides a gateway for alien species to invade the site of disturbance. In this regard, it is recommended that a strict Alien management plan be implemented to manage further encroachment and to ensure continued removal of alien species already present on site.



10 REFERENCES Bornman, T. (2013). The ecological importance of the Slang Estuary, Oyster Bay. Illenberger & Associates. Breen, C.M. and Begg, G.W., (1989). Conservation status of southern African Wetlands. In: Biotic diversity in Southern Africa; Concepts and conservation, ed BJ Huntley. Oxford University Press, Cape Town Cooper, J. Harrison, T., and Ramm, A. (2000). Geomorphology, Ichthyofauna, Water Quality and Aesthetics of South African Estuaries. Division of Water, Environment and Forestry Technology. Environmentek. CSIR. Department of Water Affairs and Forestry (2005). A practical field procedure for identification and delineation of wetland and riparian areas Edition 1. Department of Water Affairs and Forestry, Pretoria Department of Water Affairs and Forestry (DWAF), South Africa. (2005). Fish to Tsitsikamma Water Management Area: Fish to Sundays Internal Strategic Perspective. Prepared by Ninham Shand in association with Umvoto Africa, on behalf of the Directorate National Water Resource Planning. DWAF Report no. P WMA 15/000/00/0405. Department of Water and Sanitation. 2014. A Desktop Assessment of the Present Ecological State, Ecological Importance and Ecological Sensitivity per Sub Quaternary Reaches for Secondary Catchments in South Africa. Compiled by RQIS-RDM: https://www.dwa.gov.za/iwqs/rhp/eco/peseismodel.aspx accessed on 14/12/2015. Department of Water Affairs and Forestry (DWAF), South Africa. (2004). National Water Resource Strategy (NWRS). IUCN, (1980). World Conservation strategy: Living resource conservation for sustainable development. Kleynhans, C.J. (1996). A qualitative procedure for the assessment of the habitat integrity status of the Luvuvhu River. Journal of Aquatic Ecosystem Health 5: 41 - 54. Kleynhans, C.J. (1999). A procedure for the determination of the ecological reserve for the purposes of the national water balance model for South African Rivers. Institute for Water Quality Studies. Department of Water Affairs and Forestry, Pretoria. Macfarlane, D.M., Kotze D.C., Ellery, W.N., Walters, D., Koopman, V., Goodman, P., Goge, C., (2007).WET-Health: A technique for rapidly assessing wetland health. WRC Report TT 340/08, Water Research Commission, Pretoria Mucina, L. & Rutherford, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria. SANBI (2009). Further Development of a Proposed National Wetland Classification System for South Africa. Primary Project Report. Prepared by the Freshwater Consulting Group (FCG) for the South African National Biodiversity Institute (SANBI). SANBI. 2014. Statistics: Red List of South African Plants version 2014.1. Downloaded from Redlist.sanbi.org on 2014/10/15. Umvoto Africa. (2011). Reconciliation Strategy for Oyster Bay.

https://www.dwa.gov.za/iwqs/rhp/eco/peseismodel.aspx



Water Encyclopaedia (2015). Algal blooms in Freshwater. Accessed online in September 2015: http://www.waterencyclopedia.com/A-Bi/Algal-Blooms-in-Fresh-Water.html Water Services Development Plan (WSDP). (2007). Kouga Municipality.

http://www.waterencyclopedia.com/A-Bi/Algal-Blooms-in-Fresh-Water.html

Date post:	25-Jul-2020
Category:	Documents
Upload:	others
View:	2 times
Download:	0 times

SLANG RIVER LOW-LEVEL CROSSING ECOLOGICAL IMPACT … River 287_RA090216... · EOH Coastal &...

Documents