Riparian Habitat and Wetland Delineation Impact Assessment for the Proposed Turffontein Sewer Pipeline Replacement GAUTENG

Transcription

1 Riparian Habitat and Wetland Delineation Impact Assessment for the Proposed GAUTENG May 2017 REFERENCE CLIENT Prepared for: Nemai Consulting 147 Bram Fischer Drive, Ferndale, Randburg Tel: Fax: Prepared by: The Biodiversity Company 420 Vale Ave. Ferndale, 2194 Cell: Fax:

2 Report Name Riparian Habitat and Wetland Delineation Impact Assessment for the Proposed Turffontein Sewer Pipeline Replacement Reference Submitted to Nemai Consulting Report writer (Aquatics) Jaco du Plessis Report writer (Wetlands) Andrew Husted Report Reviewer Wayne Jackson 2

3 Executive Summary The Biodiversity Company was commissioned to conduct a water resource assessment, consisting of a baseline aquatic and a wetland assessment, as part of the Water Use Licence Application (WULA) for the proposed replacement of the sewer in Turffontein, City of Johannesburg Metropolitan Municipality in Gauteng Province. A single site visit was conducted from the 25 th of May Aquatic Assessment The focus for this component of the study was two aquatic sites crossed by the pipeline both are non-perennial tributaries of the Natalspruit catchment. Due to the development of the catchment area, the systems are regarded as seriously/ critically modified at a desktop level. According to the aquatic baseline survey, the Klip River and Natalspruit tributary reaches are in a seriously modified state. The aquatic macroinvertebrate communities were not assessed during the survey due to critical modification of the river characteristics. Based on visual inspection the two nonperennial tributaries have been modified to a point where the rivers have lost ecosystem function. If the systems had to be sampled for macroinvertebrates, only very tolerant taxa (not sensitive) would be expected. The biotic integrity in systems at sites Turf 3 and Turf 4 were categorised as seriously modified (PES Class E/F). No Fish are expected to occur within the aquatic areas directly associated with the proposed pipeline upgrades. However, fish are expected within the larger river systems downstream of the project area. Wetland Assessment Two (2) HGM types were identified within the 500m project assessment boundaries, namely a Channelled Valley Bottom and a Seep (Wemmerpan). A total of two (2) HGM units will be affected by the proposed route, both channelled valley bottom wetlands. The PES of the HGM units was determined to be critically and largely modified. The EIS for HGM 1 and HGM 2 was determined to be Low and Moderate respectively. The Hydrological Importance of HGM 1 and HGM 2 were determined to be Moderate. The Direct Human benefit for both HGM units were rated as Low. HGM 1 and HGM 2 had an overall moderately low and intermediate level of service respectively. Buffer zones were suggested for the HGM type to address the vulnerability of the systems to impacts. A 15m and 20m the buffer zone was determined for the HGM type for the construction and operational phases respectively. Risk Assessment The risk assessment has focussed on the pipeline segments that are either on the periphery, or within the delineated wetland areas. The replacement of the pipeline infrastructure does pose a risk to the identified water resources, with the majority of the risks determined to be low. Only the excavation (digging) 3

4 in the watercourse to remove and replace the pipeline poses a moderate risk, without mitigation. The moderate risk (without mitigation) identified for the operational phase of the project may be attributed to the risk associated with a leaking sewerage pipeline, and the operational lifespan associated with the risk. The operation of the pipeline is expected to have a low risk, owing to the fact that this project is for the replacement of a dilapidated sewer pipeline. Hence, the moderate risk rating was re-allocated a low status should the following recommendations and mitigation measures be implemented. The assessed water resources are in a modified state, offering a low level of ecological service and benefit. There is no reason for the project to not proceed, but all prescribed mitigation measures and recommendations must be implemented. Aspect Without Mitigation With Mitigation CONSTRUCTION PHASE Clearing of areas Low Low Stripping and stockpiling of soil Low Low Excavation in watercourse Moderate Low Removal of pipeline Low Low Storm water run-off Low Low Access routes and working areas Low Low Replacement of pipeline Low Low Backfill of trench Low Low Additional Associated Infrastructure Low Low Operation of equipment and machinery Low Low Vehicle activity Low Low Domestic and industrial waste Low Low Storage of chemicals, mixes and fuel Low Low Spills and leaks Low Low OPERATIONAL PHASE Transport of sewerage Moderate Low 4

5 Turffontein Sewer Replacement Table of Contents INTRODUCTION Background Objectives... 1 KEY LEGISLATIVE REQUIREMENTS National Water Act (NWA, 1998) National Environmental Management Act (NEMA, 1998)... 2 PROJECT AREA... 3 LIMITATIONS... 3 METHODOLOGY Aquatic Assessment Biotic Integrity Based on SASS5 Results Expected Fish Species Wetland Assessment Wetland Classification System Desktop assessment Wetland Delineation Wetland Present Ecological Status Wetland Ecosystem Services Ecological Importance and Sensitivity (EIS) Risk assessment Buffer Determination RESULTS & DISCUSSIONS Desktop Assessment Geology & Soils National Freshwater Ecosystem Priority Area (NFEPA) Status NFEPA s for sub-quaternary catchments Present Ecological Status (PES) Wetland NFEPAs City of Johannesburg wetlands i

6 6.2 Aquatic Assessment Habitat assessment Aquatic macroinvertebrates Biotic Integrity based on SASS5 Results Fish Wetland Assessment Wetland PES Ecosystem Services Assessment Ecological Importance & Sensitivity (EIS) Buffer Zones RISK ASSESSMENT Current impacts Recommendations Mitigation for altered surface and/or interflow, & hydrological regime Mitigation for impaired water quality Mitigation for erosion & sedimentation Mitigation for alien vegetation establishment Pipeline trench rehabilitation measures CONCLUSIONS REFERENCES ii

7 Tables Table 1: Biological Bands / Ecological categories for interpreting SASS data (adapted from Dallas, 2007)... 6 Table 2: Expected species list for the two sub-quaternary catchments... 7 Table 3: The magnitude of impacts on wetland functionality (Macfarlane, et al., 2009) Table 4: The PES categories (Macfarlane, et al., 2009) Table 5: Classes for determining the likely extent to which a benefit is being supplied (Kotze, Marneweck, Batchelor, Lindley, & Collins, 2009) Table 6: Description of EIS categories Table 7: Significance ratings matrix Table 8: FEPA s registered for the SQR s Table 9: PES of the Klip Sub-quaternary reach C22A Table 10: PES of the Natalspruit SQR C22B Table 11: The NFEPA wetland classification Table 12: Photos, co-ordinates and descriptions for the sites visited Table 13: Wetland classification as per SANBI guideline (Ollis, Snaddon, Job, & Mbona, 2013) Table 14: The PES results for the wetlands Table 15: The Eco-Services being provided by the wetland HGM units Table 16: The EIS results for the road route Table 17: The risk results from the buffer model for the proposed pipeline Table 18: The buffer zones determined for the HGM type, for the respective phases Table 19: Impacts assessed for the proposed project Table 20: DWS Risk Impact Matrix for the proposed project Table 21: DWS Risk Impact Matrix for the proposed project continued iii

8 Figures Figure 1: General locality map of the proposed sewer pipeline replacements... 3 Figure 2: Methodologies applied during the aquatic survey... 5 Figure 3: Biological Bands for the Highveld - Upper Ecoregion, calculated using percentiles 6 Figure 4: Cross section through a wetland, indicating how the soil wetness and vegetation indicators change (Ollis, Snaddon, Job, & Mbona, 2013)... 9 Figure 5: The NFEPA wetlands within 500m of the pipeline route Figure 6: The CoJ wetlands associated with the project Figure 7: Map showing location of the aquatic sampling points and project structures Figure 8: The project area wetland delineation Figure 9: Photographs of the wetland areas assessed for the study Figure 10: The project area HGM units Figure 11: The spider diagram for Eco-Services rendered by HGM units Figure 12: Photographic evidence of current impacts associated with the sewer replacement project area iv

9 DECLARATION I, Jaco du Plessis declare that: I act as the independent specialist in this application; I will perform the work relating to the application in an objective manner, even if this results in views and findings that are not favourable to the applicant; I declare that there are no circumstances that may compromise my objectivity in performing such work; I have expertise in conducting the specialist report relevant to this application, including knowledge of the Act, regulations and any guidelines that have relevance to the proposed activity; I will comply with the Act, regulations and all other applicable legislation; I have no, and will not engage in, conflicting interests in the undertaking of the activity; I undertake to disclose to the applicant and the competent authority all material information in my possession that reasonably has or may have the potential of influencing any decision to be taken with respect to the application by the competent authority; and the objectivity of any report, plan or document to be prepared by myself for submission to the competent authority; all the particulars furnished by me in this form are true and correct; and I realise that a false declaration is an offence in terms of Regulation 71 and is punishable in terms of Section 24F of the Act. Jaco du Plessis Aquatic Ecologist The Biodiversity Company 26 th May 2017 v

10 I, Andrew Husted declare that: I act as the independent specialist in this application; I will perform the work relating to the application in an objective manner, even if this results in views and findings that are not favourable to the applicant; I declare that there are no circumstances that may compromise my objectivity in performing such work; I have expertise in conducting the specialist report relevant to this application, including knowledge of the Act, regulations and any guidelines that have relevance to the proposed activity; I will comply with the Act, regulations and all other applicable legislation; I have no, and will not engage in, conflicting interests in the undertaking of the activity; I undertake to disclose to the applicant and the competent authority all material information in my possession that reasonably has or may have the potential of influencing any decision to be taken with respect to the application by the competent authority; and the objectivity of any report, plan or document to be prepared by myself for submission to the competent authority; all the particulars furnished by me in this form are true and correct; and I realise that a false declaration is an offence in terms of Regulation 71 and is punishable in terms of Section 24F of the Act. Andrew Husted Wetland Specialist The Biodiversity Company 26 th May 2017 vi

11 Turffontein Sewer Replacement INTRODUCTION The Biodiversity Company was commissioned to conduct a water resource assessment, consisting of a baseline aquatic and a wetland assessment, as part of the Water Use Licence Application (WULA) for the proposed replacement of the sewer in Turffontein, City of Johannesburg Metropolitan Municipality in Gauteng Province. A single site visit was conducted from the 25 th of May Background Johannesburg Water (JW) propose to replace an existing 3km clay sewer pipeline of 160mm diameter with a 200mm diameter HDPE pipe in Turffontein. Sections of the pipeline crosses a river and falls within 500m of a wetland and may fall within the 1:100 year floodlines thus triggering a Water Use Licence Application (WULA). 1.2 Objectives The aim of the assessment is to provide information to guide the construction and operation of the proposed sewer replacements with respect to the current state of the aquatic and wetland systems in the area of study. As part of the water resource assessment, the following objective specifics were considered: The characterisation of the current state of the local river systems; The delineation and assessment of wetlands within 500m of the project area; Evaluate the extent of site-related effects in terms of selected ecological indicators; A risk assessment for the proposed development; and The prescription of mitigation measures and recommendations for identified risks. KEY LEGISLATIVE REQUIREMENTS 2.1 National Water Act (NWA, 1998) The Department of Water & Sanitation (DWS) is the custodian of South Africa s water resources and therefore assumes public trusteeship of water resources, which includes watercourses, surface water, estuaries, or aquifers. The National Water Act (NWA) (Act No. 36 of 1998) allows for the protection of water resources, which includes: The maintenance of the quality of the water resource to the extent that the water resources may be used in an ecologically sustainable way; The prevention of the degradation of the water resource; and The rehabilitation of the water resource. A watercourse means: A river or spring; A natural channel in which water flows regularly or intermittently; A wetland, lake or dam into which, or from which, water flows; and 1

12 Any collection of water which the Minister may, by notice in the Gazette, declare to be a watercourse, and a reference to a watercourse includes, where relevant, its bed and banks. The NWA recognises that the entire ecosystem, and not just the water itself, and any given water resource constitutes the resource and as such needs to be conserved. No activity may therefore take place within a watercourse unless it is authorised by the DWS. For the purposes of this project, a wetland area is defined according to the NWA (Act No. 36 of 1998): 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. Wetlands have one or more of the following attributes to meet the NWA wetland definition (DWAF, 2005): A high water table that results in the saturation at or near the surface, leading to anaerobic conditions developing in the top 50 cm of the soil; Wetland or hydromorphic soils that display characteristics resulting from prolonged saturation, i.e. mottling or grey soils; and The presence of, at least occasionally, hydrophilic plants, i.e. hydrophytes (water loving plants). 2.2 National Environmental Management Act (NEMA, 1998) The National Environmental Management Act (NEMA) (Act 107 of 1998) and the associated Regulations as amended in April 2017, states that prior to any development taking place within a wetland or riparian area, an environmental authorisation process needs to be followed. This could follow either the Basic Assessment Report (BAR) process or the Environmental Impact Assessment (EIA) process depending on the scale of the impact. 2

13 Turffontein Sewer Replacement PROJECT AREA The proposed project is situated in the quaternary catchments C22A and C22B, within the Vaal Water Management Area (WMA 5) and Highveld Ecoregion (Figure 1). The route does traverse the upper reaches of tributaries associated with the Natalspruit system. Figure 1: General locality map of the proposed sewer pipeline replacements LIMITATIONS The following aspects were considered as limitations for the water resource assessment; Not all areas aligned with the road route could be comprehensively assessed, this is due largely to private land ownership. A desktop study was conducted in order to supplement this limitation. The study area is well developed, with developed areas encroaching into the wetlands. Due to this, and also taking into account the study was conducted in an early dry season period, wetland indicators were not readily available to assist with the delineation of areas. The aquatic baseline assessment was based on the results of a single low flow survey only, and information provided should be interpreted accordingly. The wetland baseline assessment was based on the results of a single dry season survey only, and information provided should be interpreted accordingly. 3

14 The GPS used for wetland delineations is accurate to within five meters. Therefore, the wetland delineation plotted digitally may be offset by at least five meters to either side. Wetland systems identified at desktop level within 500 m of the project area were considered for the identification and desktop delineation, with wetland areas within the project area being the focus for ground truthing. 4

15 METHODOLOGY 5.1 Aquatic Assessment Various assessments conducted during the survey are illustrated in Figure 2. In situ water quality analysis Habitat Assessments (IHAS) Kick and sweep sampling method, SASS5 (South African Scoring System Version 5) Figure 2: Methodologies applied during the aquatic survey Biotic Integrity Based on SASS5 Results Reference conditions reflect the best conditions that can be expected in rivers and streams within a specific area and also reflect natural variation over time. These reference conditions are used as a benchmark against which field data can be compared. Modelled reference conditions for the Highveld Ecoregion were obtained from Dallas (2007) (Table 1). The biological bands for the Highveld Ecoregions are presented in Figure 3. 5

16 Table 1: Biological Bands / Ecological categories for interpreting SASS data (adapted from Dallas, 2007) Class Ecological Category Description A B C D E/F Natural Largely natural Moderately modified Largely modified Seriously Modified Unimpaired. High diversity of taxa with numerous sensitive taxa. Slightly impaired. High diversity of taxa, but with fewer sensitive taxa. Moderately impaired. Moderate diversity of taxa. Considerably impaired. Mostly tolerant taxa present. Severely impaired. Only tolerant taxa present. Figure 3: Biological Bands for the Highveld - Upper Ecoregion, calculated using percentiles 6

17 5.1.2 Expected Fish Species The list of expected fish species is presented in Table 2 (Skelton, 2001; DWS, 2013). Based on this, a total of 9 fish species are expected to occur in the project area. It should be noted that these expected species lists are compiled on a catchment area or Sub- Quaternary Reach (SQR) basis and not on a site-specific basis. It is therefore unlikely that all of the expected species will be present at every site in the SQR with habitat type and availability being the main driver of species present. Therefore, Table 2 should be viewed as a list of potential species rather than an expected species list. Table 2: Expected species list for the two sub-quaternary catchments Scientific name Common name IUCN Status Klip Natalspruit Clarias gariepinus Sharptooth Catfish LC X Enteromius anoplus Chubbyhead Barb LC X Enteromius pallidus Goldie Barb LC X Enteromius paludinosus Straightfin Barb LC X Labeo capensis Orange River Labeo LC X Labeobarbus aeneus Smallmouth Yellowfish LC X Labeo umbratus Moggel LC X Pseudocrenilabrus philander Southern Mouthbrooder DD X X Tilapia sparrmanii Banded Tilapia LC X X Total number of expected species 9 2 LC - Least Concern; DD Data Deficient 5.2 Wetland Assessment The National Wetland Classification Systems (NWCS) developed by the South African National Biodiversity Institute (SANBI) will be considered for this study. This system comprises a hierarchical classification process of defining a wetland based on the principles of the hydrogeomorphic (HGM) approach at higher levels, and also then includes structural features at the lower levels of classification (Ollis, Snaddon, Job, & Mbona, 2013) Wetland Classification System A distinction is made between four Landscape Units for Inland Systems on the basis of the landscape setting in which a HGM is situated, which broadly considers (Ollis, Snaddon, Job, & Mbona, 2013): Slope; Valley floor; Plain; and Bench. 7

18 The HGM Units, which are defined primarily according to: Landform, which defines the shape and localised setting of a wetland; Hydrological characteristics, which describe the nature of water movement into, through and out of the wetland; and Hydrodynamics, which describe the direction and strength of flow through the wetland. Seven primary HGM units are recognised for Inland Systems on the basis of hydrology and geomorphology (Ollis, Snaddon, Job, & Mbona, 2013), namely: River: a linear landform with clearly discernible bed and banks, which permanently or periodically carries a concentrated flow of water; Channelled valley-bottom wetland: a valley-bottom wetland with a river channel running through it; Unchannelled valley-bottom wetland: a valley-bottom wetland without a river channel running through it; Floodplain wetland: the mostly flat or gently sloping land adjacent to and formed by an alluvial river channel, under its present climate and sediment load, which is subject to periodic inundation by over-topping of the channel bank; Depression: a landform with closed elevation contours that increases in depth from the perimeter to a central area of greatest depth, and within which water typically accumulates; Wetland Flat: a level or near-level wetland area that is not fed by water from a river channel, and which is typically situated on a plain or a bench. Closed elevation contours are not evident around the edge of a wetland flat; and Seep: a wetland area located on (gently to steeply) sloping land, which is dominated by the colluvium (i.e. gravity-driven), unidirectional movement of material down-slope. Seeps are often located on the side-slopes of a valley but they do not, typically, extend into a valley floor. The above terms have been used in order to ensure consistency with the wetland classification terms in South Africa Desktop assessment The following information sources were considered for the desktop assessment; Information as presented by the South African National Biodiversity Institutes (SANBI s) Biodiversity Geographic Information Systems (BGIS) website ( City of Johannesburg wetland audit (2009). Aerial imagery (Google Earth Pro); Land Type Data (Land Type Survey Staff, ); The National Freshwater Ecosystem Priority Areas (Nel, et al., 2011); Contour data (5m). 8

19 5.2.3 Wetland Delineation The wetland areas are delineated in accordance with the DWAF (2005) guidelines, a cross section is presented in Figure 4. The outer edges of the wetland areas were identified by considering the following four specific indicators: The Terrain Unit Indicator helps to identify those parts of the landscape where wetlands are more likely to occur; The Soil Form Indicator identifies the soil forms, as defined by the Soil Classification Working Group (1991), which are associated with prolonged and frequent saturation. The soil forms (types of soil) found in the landscape were identified using the South African soil classification system namely; Soil Classification: A Taxonomic System for South Africa (Soil Classification Working Group, 1991); The Soil Wetness Indicator identifies the morphological "signatures" developed in the soil profile as a result of prolonged and frequent saturation; and The Vegetation Indicator identifies hydrophilic vegetation associated with frequently saturated soils. Vegetation is used as the primary wetland indicator. However, in practise the soil wetness indicator tends to be the most important, and the other three indicators are used in a confirmatory role. Figure 4: Cross section through a wetland, indicating how the soil wetness and vegetation indicators change (Ollis, Snaddon, Job, & Mbona, 2013) Wetland Present Ecological Status Healthy wetlands are known to provide important habitats for wildlife and to deliver a range of important goods and services to society (ecosystem services). Management of these systems is therefore essential if these attributes are to be retained within an ever-changing landscape. The primary purpose of this assessment is to evaluate the eco-physical health of wetlands, and in so doing promote their conservation and wise management. 9

20 Level of Evaluation WET-Health provides two levels of assessment: Level 1: Desktop evaluation, with limited field verification. This is generally applicable to situations where many wetlands need to be assessed at a very low resolution; or Level 2: On-site evaluation. This involves structured sampling and data collection in a single wetland and its surrounding catchment. Units of Assessment Central to WET-Health is the characterisation of HGM Units, which have been defined based on geomorphic setting (e.g. hillslope or valley-bottom and whether drainage is open or closed), water source (surface water dominated or sub-surface water dominated) and pattern of water flow through the wetland unit (diffusely or channelled). Quantification of Present Ecological State (PES) of a Wetland The overall approach is to quantify the impacts of human activity or clearly visible impacts on wetland health, and then to convert the impact scores to a PES score. This takes the form of assessing the spatial extent of impact of individual activities/occurrences and then separately assessing the intensity of impact of each activity in the affected area. The extent and intensity are then combined to determine an overall magnitude of impact. The impact scores and Present State categories are provided in Table 3 and Table 4. Table 3: The magnitude of impacts on wetland functionality (Macfarlane, et al., 2009) Impact Category None Description No Discernible modification or the modification is such that it has no impacts on the wetland integrity Score 0 to 0.9 Small Although identifiable, the impact of this modification on the wetland integrity is small. 1.0 to 1.9 Moderate Large Serious Critical The impact of this modification on the wetland integrity is clearly identifiable, but limited. The modification has a clearly detrimental impact on the wetland integrity. Approximately 50% of wetland integrity has been lost. The modification has a highly detrimental effect on the wetland integrity. More than 50% of the wetland integrity has been lost. The modification is so great that the ecosystem process of the wetland integrity is almost totally destroyed, and 80% or more of the integrity has been lost. 2.0 to to to to 10 10

21 Table 4: The PES categories (Macfarlane, et al., 2009) Impact Category Description Impact Score Range Present State Category None Unmodified, natural 0 to 0.9 A Small Moderate Large Serious Critical Largely Natural with few modifications. A slight change in ecosystem processes is discernible and a small loss of natural habitats and biota may have taken place. Moderately Modified. A moderate change in ecosystem processes and loss of natural habitats has taken place, but the natural habitat remains predominantly intact. Largely Modified. A large change in ecosystem processes and loss of natural habitat and biota has occurred. Seriously Modified. The change in ecosystem processes and loss of natural habitat and biota is great, but some remaining natural habitat features are still recognizable. Critical Modification. The modifications have reached a critical level and the ecosystem processes have been modified completely with an almost complete loss of natural habitat and biota. 1.0 to 1.9 B 2.0 to 3.9 C 4.0 to 5.9 D 6.0 to 7.9 E 8.0 to 10 F Overall Health of the Wetland Once all HGM Units have been assessed, a summary of health for the wetland as a whole is calculated. Since hydrology, geomorphology and vegetation are interlinked their scores are aggregated to obtain an overall PES health score using the following formula (Macfarlane, et al., 2009): Health = ((Hydrology score) x3 + (Geomorphology score) x2 + (Vegetation score) x2)) Wetland Ecosystem Services The assessment of the ecosystem services supplied by the identified wetlands was conducted per the guidelines as described in WET-EcoServices (Kotze, Marneweck, Batchelor, Lindley, & Collins, 2009). An assessment was undertaken that examines and rates the following services according to their degree of importance and the degree to which the services are provided ( Table 5): Flood attenuation Stream flow regulation Sediment trapping Phosphate trapping Nitrate removal Toxicant removal Erosion control Carbon storage Maintenance of biodiversity Water supply for human use Natural resources Cultivated foods Cultural significance Tourism and recreation Education and research 11

22 Table 5: Classes for determining the likely extent to which a benefit is being supplied (Kotze, Marneweck, Batchelor, Lindley, & Collins, 2009) Score Rating of likely extent to which a benefit is being supplied < 0.5 Low Moderately Low Intermediate Moderately High > 3.0 High Ecological Importance and Sensitivity (EIS) The method used for the EIS determination was adapted from the method as provided by DWS (1999) for floodplains. The method takes into consideration PES scores obtained for WET-Health as well as function and service provision to enable the assessor to determine the most representative EIS category for the wetland feature or group being assessed. A series of determinants for EIS are assessed on a scale of 0 to 4, where 0 indicates no importance and 4 indicates very high importance. The mean of the determinants is used to assign the EIS category as listed in Table 6. Table 6: Description of EIS categories EIS Category Range of Mean Recommended Ecological Management Class Very High 3.1 to 4.0 A High 2.1 to 3.0 B Moderate 1.1 to 2.0 C Low Marginal < 1.0 D 5.3 Risk assessment The matrix assesses impacts in terms of consequence and likelihood. Consequence is calculated based on the following formula: Whereas likelihood is calculated as: Consequence = Severity + Spatial Scale + Duration Likelihood=Frequency of Activity + Frequency of Incident +Legal Issues + Detection. Significance is calculated as: Significance \Risk= Consequence X Likelihood. The significance of the impact is calculated according to Table

23 Table 7: Significance ratings matrix Rating Class Management Description 1 55 (L) Low Risk M) Moderate Risk (H) High Risk Acceptable as is or consider requirement for mitigation. Impact to watercourses and resource quality small and easily mitigated. Wetlands may be excluded. Risk and impact on watercourses are notably and require mitigation measures on a higher level, which costs more and require specialist input. Wetlands are excluded. Always involves wetlands. Watercourse(s)impacts by the activity are such that they impose a long-term threat on a large scale and lowering of the Reserve. 5.4 Buffer Determination A buffer zone is defined as A strip of land with a use, function or zoning specifically designed to protect one area of land against impacts from another. (Macfarlane, et al., 2014). Buffer zones protect water resources in a variety of ways, such as; Maintenance of basic aquatic processes; The reduction of impacts on water resources from activities and adjoining land uses; The provision of habitat for aquatic and semi-aquatic species; The provision of habitat for terrestrial species; and The provision of societal benefits. The Preliminary Guideline for the Determination of Buffer Zones for Rivers, Wetlands and Estuaries (Macfarlane et al. 2014) was used to determine the appropriate buffer zone for the proposed activity. 13

24 RESULTS & DISCUSSIONS 6.1 Desktop Assessment Geology & Soils The geology of the area is mainly Witwatersrand quartzite, slate, grit and conglomerate predominantly. Black Reef quartzite, shale, grit and conglomerate in western part. Ecca shale and sandstone with occasional dolerite sills in east. Sporadic occurrence of Basement Complex granite, dolomite and Ventersdorp lava mainly to the west. According to the land type database (Land Type Survey Staff, ) the development falls within the Ba35 and Ba36 land types. It is expected that, the dominant soils in the crest and midslope positions will be soils of the Glenrosa, Glencoe and Mispah soil forms. The soils that dominated the footslopes and the valley bottoms are Rensburg and Dundee soil forms National Freshwater Ecosystem Priority Area (NFEPA) Status The National Freshwater Ecosystem Priority Areas (NFEPA) database forms part of a comprehensive approach to the sustainable and equitable development of South Africa s scarce water resources. This database provides guidance on how many rivers, wetlands and estuaries, and which ones, should remain in a natural or near-natural condition to support the water resource protection goals of the National Water Act (Act 36 of 1998). This directly applies to the National Water Act, which feeds into Catchment Management Strategies, water resource classification, reserve determination, and the setting and monitoring of resource quality objectives (Nel et al. 2011). The NFEPAs are intended to be conservation support tools and envisioned to guide the effective implementation of measures to achieve the National Environment Management Biodiversity Act s biodiversity goals (NEM:BA) (Act 10 of 2004), informing both the listing of threatened freshwater ecosystems and the process of bioregional planning provided for by this Act (Nel et al. 2011) NFEPA s for sub-quaternary catchments The project area has designated freshwater priority areas for the Klip SQR only, these are presented in Table 8. Table 8: FEPA s registered for the SQR s Type of FEPA map category Biodiversity features Klip SQR C22A-1315 Number of wetland clusters Wetland ecosystem type Wetland ecosystem type Wetland ecosystem type 3 WetCluster FEPAs Central Bushveld Group 1_Channelled valley-bottom wetland Mesic Highveld Grassland Group 3_Depression Mesic Highveld Grassland Group 3_Seep NatalspruitSQR C22B-1360 None 14

25 6.1.4 Present Ecological Status (PES) This section provides further desktop information regarding the Klip SQR C22A-1315 and the Natalspruit SQR C22B-1360 with regards to the PES including the Ecological Importance, Ecological Sensitivity and anthropogenic impacts within each SQR. Desktop information was obtained from DWS (2013). The study area falls under two SQRs comprising both the Klip River and Natalspruit Catchment. The PES category of each reach is classed as Seriously Modified (Class E) and Critically Modified (Class F) (Table 9 to Table 10). The seriously modified state of the reach is attributed to large to serious impacts to instream habitat, wetland and riparian zone continuity, flow modifications and potential impacts on physico-chemical conditions (water quality). 15

26 Turffontein Sewer Replacement Table 9: PES of the Klip Sub-quaternary reach C22A-1315 Present Ecological State Ecological Importance Ecological Sensitivity E (Seriously Modified) Moderate Moderate Variable Status Variable Status Variable Status Modifications to Instream Habitat Continuity Large Fish species per sub quaternary catchment 9 Fish Physico-Chemical sensitivity description High Modifications to Riparian/ Wetland Zone Continuity Large Invertebrate taxa per sub quaternary catchment 27 Fish No-flow sensitivity description High Potential Instream Habitat Modifications Serious Habitat Diversity Class Moderate Invertebrate Physico- Chemical sensitivity Moderate Modifications to Riparian/ Wetland Zones Potential Flow Modifications Potential Physico-Chemical Modifications Serious Instream Migration Link Class Moderate Serious Serious Riparian-Wetland Zone Migration Link Instream Habitat Integrity Class Moderate Low Invertebrate velocity sensitivity Stream size sensitivity to modified flow/water level changes description Riparian-Wetland Vegetation intolerance to water level changes description Very High Low Low Anthropogenic Impacts The following impacts/activities were identified: Urban (Roodepoort) at source, mining areas, urban (Soweto), Olifantsfontein & other WWTWs, siltation, road crossings, increased flows 16

27 Table 10: PES of the Natalspruit SQR C22B-1360 Present Ecological State Ecological Importance Ecological Sensitivity F (Critically Modified) Low Low Variable Status Variable Status Variable Status Modifications to Instream Habitat Continuity Critical Fish species per sub quaternary catchment 2 Fish Physico-Chemical sensitivity description Low Modifications to Riparian/ Wetland Zone Continuity Critical Invertebrate taxa per sub quaternary catchment 15 Fish No-flow sensitivity description Low Potential Instream Habitat Modifications Critical Habitat Diversity Class Moderate Invertebrate Physico- Chemical sensitivity Moderate Modifications to Riparian/ Wetland Zones Potential Flow Modifications Potential Physico-Chemical Modifications Critical Instream Migration Link Class Very Low Moderate Serious Riparian-Wetland Zone Migration Link Instream Habitat Integrity Class Very Low Very Low Invertebrate velocity sensitivity Stream size sensitivity to modified flow/water level changes description Riparian-Wetland Vegetation intolerance to water level changes description High Low High Anthropogenic Impacts The following impacts/activities were identified: Old gold mines, industrial, water quality 17

28 Turffontein Sewer Replacement Wetland NFEPAs Wemmerpan and an isolated seepage area are the only NFEPA wetland systems that were identified within the 500m assessment buffer of the project. Wemmerpan is approximately 300m north of the pipeline route. The systems are considered to be in a seriously to largely modified state, with some systems classified as artificial. The systems within 500m of the pipeline are a Rank 6, the lowest ranking afforded to wetlands, suggesting a very low level of ecological significance. A summary of the NFEPA characteristics is presented in Table 11 and Figure 5. Table 11: The NFEPA wetland classification Level 1 Level 2 Level 4 System DWS NFEPA Wet Veg Ecoregion/s Group/s 4A (HGM) Inland Highveld Mesic Highveld Grassland Group 3 Seep Status Largely to seriously modified Rank Natural / Artificial 6 Nat & Art Figure 5: The NFEPA wetlands within 500m of the pipeline route City of Johannesburg wetlands A wetland audit was completed for the City of Johannesburg (2009) with the intention of locating wetland areas that may then be considered for spatial planning. The available dataset was considered in order to identify any possible wetland areas in close proximity to the project area. The dataset does indicate the presence of channelled valley bottom wetlands within the 500m buffer area (Figure 6). 18

29 Figure 6: The CoJ wetlands associated with the project 19

30 6.2 Aquatic Assessment The focus for the study was two aquatic sites of the Natalspruit catchment, Turf 3 is situated upstream of Wemmerpan and Turf 4 situated closer to the N17 Highway (Figure 7). A site description, photographs and GPS coordinates for the sampled river reach are presented in Table 12. The area surrounding the project servitudes consists of high-density residential developments. The activities in the area and local land uses have had impacts to the resources and visible disturbances were excessive. Due to these activities, the system is regarded as seriously modified at a desktop level. Figure 7: Map showing location of the aquatic sampling points and project structures 20

31 Table 12: Photos, co-ordinates and descriptions for the sites visited Upstream Downstream Turf 4 GPS 26 14'13.09"S 28 5'10.34"E Site Turf 4 is a non-perennial tributary of the Natalspruit catchment. The site is characterized by slow polluted flowing waters over gravel, sand and mud. Onsite impacts Impacts from extremely large amounts of solid waste and grey water were noted. Upstream Downstream Turf 3 GPS Site Onsite impacts 26 14'11.93"S 28 3'45.80"E Turf 3 is a non-perennial tributary of the Natalspruit catchment, upstream of the Wemmerpan. The site is characterized by slow flowing waters over sandy substrate. The site could not be accessed. Impacts from small amounts of solid waste and grey water were noted 21

32 6.2.1 Habitat assessment The Invertebrate Habitat Assessment System (IHAS) index was developed by McMillan (1998) for use in conjunction with the SASS5 protocol. IHAS could not be applied at site as the SASS5 protocol was not conducted Aquatic macroinvertebrates The aquatic macroinvertebrate communities were not assessed during the survey due to critical modification of both the river characteristics and water quality Biotic Integrity based on SASS5 Results Biotic integrity in the tributaries of the Natalspruit (Turf 3 & Turf 4) were categorised as seriously modified (PES Class E/F). Based on visual inspection the two river crossings have been modified to a point where the rivers have lost ecosystem function. If the systems had to be sampled for macroinvertebrates, only very few tolerant taxa (not sensitive) would be expected Fish No fish are expected to occur within the aquatic areas directly associated with the proposed Sewer pipeline replacement. However, fish are expected within the larger river systems downstream of the project area. 22

33 6.3 Wetland Assessment The wetland survey included assessing all the wetland indicators as well as assessing the Present Ecological Score (PES) or health of the wetland, the wetland s ability to provide goods and services (Eco-Services) and the Ecological Importance and Sensitivity (EIS) of the wetlands. The wetland delineation is shown in Figure 8 with the wetland classification as per SANBI guidelines (Ollis, Snaddon, Job, & Mbona, 2013) in Table 13. Photographs of the HGM types identified for the study are presented in Figure 9. Two (2) HGM types were identified within the 500m project assessment boundaries, namely: Channelled Valley Bottom; Seep (Wemmerpan). A total of two (2) HGM units will be affected by the proposed route, both channelled valley bottom wetlands. Figure 10 presents the two HGM units that will be closely considered for the study. Figure 8: The project area wetland delineation 23

34 Figure 9: Photographs of the wetland areas assessed for the study Table 13: Wetland classification as per SANBI guideline (Ollis, Snaddon, Job, & Mbona, 2013) Level 1 Level 2 Level 3 Level 4 Name DWS NFEPA Wet Veg Landscape System 4A (HGM) 4B 4C Ecoregion/s Group/s Unit Mesic Highveld Channelled HGM 1 & 2 Inland Highveld Valley Floor N/A N/A Grassland Group 3 Valley Bottom Figure 10: The project area HGM units Wetland PES The PES results are described in the sections below with Table 14 showing the combined results. A summary of aspects that have impacted on the wetland systems is discussed below. 24

35 Hydrology: The hydrology of the general area has been altered significantly. A considerable extent of HGM 1 has been developed to accommodate storm water, which has resulted in the system being contained within culverts and covered. The development of the area has resulted in storm water being diverted to the system from adjacent areas. Water release from Wemmerpan into the downstream systems has also altered the hydrological regime of the system. Geomorphology: A considerable extent of HGM 1 has been developed into an underground storm water system, which has resulted in these wetland areas being seriously modified. In addition to this, the development of the catchment has encroached into the wetland areas, resulting in the narrowing of these systems. The extent of developed areas, and the local access routes have also resulted in flow paths being altered which has also caused changes to the structure of the systems Vegetation: Due to the development of the area, wetland vegetation has largely been lost for a considerable extent of HGM 1. The encroachment of developments into these areas, and the associated disturbances have resulted in the establishment of alien vegetation in the systems. Table 14: The PES results for the wetlands Wetland Hydrology Geomorphology Vegetation Rating Score Rating Score Rating Score HGM 1 E: Seriously Modified 7.8 F: Critically Modified 9.2 F: Critically Modified 8.0 Overall PES Score 8.3 Overall PES Class F: Critically Modified Wetland Hydrology Geomorphology Vegetation Rating Score Rating Score Rating Score HGM 2 E: Seriously Modified 7.2 D: Largely Modified 4.6 C: Moderately Modified 3.2 Overall PES Score 5.3 Overall PES Class D: Largely Modified Ecosystem Services Assessment The Ecosystem services provided by the HGM unit present at the site were assessed sing the WET-EcoServices method (Kotze, Marneweck, Batchelor, Lindley, & Collins, 2009). The summarised results for the HGM units are shown in Table 15. HGM 1 and HGM 2 had an overall moderately low and intermediate level of service respectively. Only two services providing moderately high benefits were identified for the study, both services are associated with HGM 2, and these include sediment trapping and toxicant assimilation. The remaining services for the HGM units were scored as intermediate or lower. 25

36 Table 15: The Eco-Services being provided by the wetland HGM units Wetland Unit HGM 1 HGM 2 Flood attenuation Ecosystem Services Supplied by Wetlands Indirect Benefits Direct Benefits Regulating and supporting benefits Provisioning benefits Cultural benefits Streamflow regulation Water Quality enhancement benefits Sediment trapping Phosphate assimilation Nitrate assimilation Toxicant assimilation Erosion control Carbon storage Biodiversity maintenance Provisioning of water for human use Provisioning of harvestable resources Provisioning of cultivated foods Cultural heritage Tourism and recreation Education and research Overall Average Figure 11: The spider diagram for Eco-Services rendered by HGM units 26

37 6.3.3 Ecological Importance & Sensitivity (EIS) The EIS assessment was applied to the HGM units described in the previous section in order to assess the levels of sensitivity and ecological importance of the wetland. The results of the assessment are shown in Table 16. The EIS for HGM 1 and HGM 2 was determined to be Low and Moderate respectively. The Hydrological Importance of HGM 1 and HGM 2 were determined to be Moderate. The Direct Human benefit for both HGM units were rated as Low. Table 16: The EIS results for the road route WETLAND IMPORTANCE AND SENSITIVITY HGM 1 Importance ECOLOGICAL IMPORTANCE & SENSITIVITY 0.3 HYDROLOGICAL/FUNCTIONAL IMPORTANCE 1.2 DIRECT HUMAN BENEFITS 0.5 HGM 2 Importance ECOLOGICAL IMPORTANCE & SENSITIVITY 1.3 HYDROLOGICAL/FUNCTIONAL IMPORTANCE 1.8 DIRECT HUMAN BENEFITS Buffer Zones The wetland buffer zone tool was used to calculate the appropriate buffer required for the pipeline. The tool shows that the largest risk (Moderate) posed by the project during the construction phase is that of increased sediment inputs and turbidity and organic contaminant inputs. During the operational phase, the only High risk is posed by the possible inputs of additional nutrients (Table 17). Buffer zones were suggested for the HGM type to address the vulnerability of the systems to impacts. Table 18 presents the buffer zones determined for the HGM type for the construction and operational phases of the project. The buffer zone would not be applicable to the traversing of the wetland by the pipeline route. However, the buffer zone is applicable to the associated activities and laydown areas that are not required within the buffer area.. 27

38 Turffontein Sewer Replacement Table 17: The risk results from the buffer model for the proposed pipeline Threat Posed by the proposed land use / activity Specialist Threat Rating Refined Threat Class Specialist justification for refined threat ratings with clear reference to supporting documentation. Construction Phase Operational Phase 1. Alteration to flow volumes VL VL 2. Alteration of patterns of flows (increased flood peaks) VL L 3. Increase in sediment inputs & turbidity M VL 4. Increased nutrient inputs N/A N/A 5. Inputs of toxic organic contaminants M L 6. Inputs of toxic heavy metal contaminants L L 7. Alteration of acidity (ph) VL VL 8. Increased inputs of salts (salinization) N/A N/A 9. Change (elevation) of water temperature VL VL 10. Pathogen inputs (i.e. disease-causing organisms) VL VL The pipeline will be replaced in an already developed area with no (or very limited) bare / open area. The replacement will take place in a storm water (concrete) setting. Maintenance of machines, equipment & vehicles off-site. Use of prefabricated materials, avoid on-site fabrication. Storage of chemicals in designated area, away from wetlands. 1. Alteration to flow volumes L VL It is the replacement of a pipeline, with no discharges at the site 2. Alteration of patterns of flows (increased flood peaks) L L 3. Increase in sediment inputs & turbidity VL VL 4. Increased nutrient inputs H M The projects is for the replacement of a dilapidated pipeline which is leaking sewerage into the system. The replacement will be beneficial for the project. 5. Inputs of toxic organic contaminants L VL It is a water pipeline, so risk of nutrient inputs is negligible 6. Inputs of toxic heavy metal contaminants L VL It is a water pipeline, so risk of nutrient inputs is negligible 7. Alteration of acidity (ph) L L 8. Increased inputs of salts (salinization) VL VL 9. Change (elevation) of water temperature VL VL 10. Pathogen inputs (i.e. disease-causing organisms) VL VL 28

39 Turffontein Sewer Replacement Table 18: The buffer zones determined for the HGM type, for the respective phases Phase Construction Operational Channelled valley bottom 15 m 20 m RISK ASSESSMENT Direct impacts to any watercourses are a key consideration for the risk assessment, these are for the areas that will be encroached upon for the replaced pipelines. The risk assessment has focussed on the pipeline segments that are either on the periphery, or within the delineated wetland areas. The proposed project will only pose a risk to the channelled valley bottom wetlands. Findings from the DWS aspect and impact register / risk assessment are provided in Table 19, Table 20 and Table Current impacts The current impacts observed along the pipeline route during the survey are listed below. Photographic evidence of a selection of these impacts is shown in Figure 12. Mining, pollution control dams; Formal and informal roads; Crossings, including bridges and causeways; Residential development; Alien and/or Invasive Plants (AIP); Water contamination; Vegetation removal; Refuse dumping; Inadequate storm water management; and Erosion. 29

40 Turffontein Sewer Replacement Figure 12: Photographic evidence of current impacts associated with the sewer replacement project area 30