ENVIROSERV CHLOORKOP LANDFILL SITE EXPANSION PROJECT WETLAND, SOIL AND LAND CAPABILITY SPECIALIST STUDY REPORT Report No.: JW100/19/6007-25 May 2019 Internet presence: www.jaws.co.za Synopsis EnviroServ Waste Management (Pty) Ltd own the existing Chloorkop Landfill Site (CLS) and operate it in terms of a waste management licence (Ref: 16/2/7/A230/D17/Z1). Municipal solid waste is received from the Midrand area, including the City of Johannesburg and the Ekurhuleni Metropolitan Municipality. The CLS is located in the Chloorkop Industrial area on Portion 63 of Klipfontein 12-IR and is accessed from Marsala Road. The waste body at the CLS has finite airspace, defined by the permitted footprint, height and design parameters and will not be able to receive waste once it reaches airspace capacity. EnviroServ is proposing to expand the CLS in order to provide additional airspace for ongoing disposal of municipal solid waste. The proposal is to expand the Chloorkop Landfill Site onto adjacent properties (Erf 334 and 335 of Chloorkop Extension 6), CLS Expansion Project. The concept is to establish engineered, Class B waste disposal cells on the target properties for ongoing disposal of municipal solid waste. The additional waste disposal cells would join with the current CLS waste body. The facility will include a small Material Recovery Facility for the separation of clean recyclables from the waste. Supporting infrastructure would be integrated with the CLS and/or redeveloped as appropriate. A municipal road, Anker Street, separates part of the expansion area from the CLS and thus a phased approach is likely. Phase 1A would entail the development and use of waste disposal cells between the current CLS and Anker Street. Phase 1B would involve the development and use of waste disposal cells on the portion of the site north of Anker street, connecting with the CLS and the Phase 1A. Phase 1B would only proceed if Anker Street had been relocated or closed (subject to municipal engagement and approvals). SLR Consulting (South Africa) (Pty) Ltd was appointed by EnviroServ to prepare the relevant applications for environmental authorisation and licensing for the proposed CLS Expansion Project. As part of the environmental authorisation process, a number of specialist investigations are required. EnviroServ have appointed Jones & Wagener (Pty) Ltd (J&W) to undertake a wetland, soils and land capability assessment for the site. The CLS Expansion project area is located within an urban area (i.e. light industries, existing CLS landfill, quarry) that is highly altered. The phase 1A footprint is currently occupied by light industrial development with the topography altered and the soils compacted. The Phase 1B footprint is occupied on the west by a large area of illegal dumping of waste material, mainly building rubble, that is over 8 m deep in places. The eastern portion of the Phase1B footprint is wetland habitat. The findings of the assessment are summarised below. Soils and land capability The soils on site were mapped using transect field samples by hand augering to refusal or 1,2m depth. No natural soils remained in the phase 1A footprint as the entire footprint has been transformed by urban activities. The Phase 1B footprint has been extensively impacted by waste dumping over the bulk of the site, with some natural soils remaining in the northern and eastern sections of the site. The Phase 1B footprint included wetland soils with signs of wetness within the top 50cm of the soil, as well as waterlogged areas on the eastern perimeter. These soils are responsive in terms of the local hydropedological system, as they are in the low point in the landscape with water accumulating along several flow paths. The limited natural soils remaining upstream indicated a shallow rock layer in the profile, allowing water to move sideways in the profile, before daylighting in the lower sections of the slope. The wetland and waterlogged soils identified should be regarded as sensitive and avoided if possible. ii Wetlands The presence of wetlands on site was determined using both desktop and in-field methodologies. No wetlands were identified within the phase 1A footprint. Three wetland HGM units were identified within the Phase 1B footprint. There is no natural watercourse upstream of the proposed Phase 1B site. All water from the upstream catchment enters the site as either stormwater or as seep from the adjacent quarry. The wetland HGM units identified on site include: • Un-channelled valley bottom Un-channelled valley bottom systems can sometimes have short sections of natural channels within them. The presence or absence of channels could not be confirmed in the field as the wetland is dominated by extensive stands of Typha capensis and Phragmites australis. The un-channelled valley bottom system has been artificially enhanced due to the discharge of stormwater, from the upstream catchment, at point locations into the system. The discharge of stormwater has resulted in a system that is seasonal to permanent in nature and would have likely been a more temporary seep associated with a seasonal channelled valley bottom system. • Channelled valley bottom. A channelled valley bottom system was identified on the northern boundary of the Phase 1B CLS Expansion site. • Seep. The seep identified on site feeds into the channelled valley bottom wetland via diffuse sub-surface flow. The current fill on the Phase 1B site is impacting the downstream seep wetland, resulting in a more seasonal to permanent system. The wetland on site were Moderately to Seriously modified, with the main impacts including: • Highly altered upstream catchment consisting isolated dirty water catchment areas, for example the existing CLS facility and of hardened surfaces, with the resultant impact on the Mean Annual Runoff entering the wetlands on site and the floodpeaks. • Gullies and drainage channels: The stormwater entering the Phase 1B site has resulted in the development of erosion channels, specifically on the eastern and western boundary of the site. • Modifications to existing channel. The discharge of stormwater at point locations, the deposition of fill within the wetland and the seepage of water from the adjacent quarry has modified the wetland system and likely increased the cross-sectional area of the unchannelled valley bottom system. Prior to the development of the catchment it is uncertain what HGM unit/s would have been present on the site, it is possible that the wetland (immediately downstream of Anker Street) would have been a more confined channelled valley bottom system flanked by a seep (as further downstream). • Surface roughness. There has likely been an increase in surface roughness due to a change in the seasonality of the wetland and the nutrient load entering the wetland, which has resulted in a dominance of species such as Phragmites australis. • Impeding features, for example the wall on the eastern boundary, between the quarry and the CLS Expansion site, and the downstream culvert entering the underground stormwater pipes. Immediately downstream of the site, the water enters a culvert and an underground stormwater pipe. • Increased on-site water use due to the alien invasive bushclumps consisting of Eucalyptus camaldulensis and Acacia mearnsii which constitute 10% of the iii wetland area. These tree species are alien invasive species and are higher water users than natural vegetation. • Deposition/infilling or excavation. Sixty eight percent of the Phase 1B CLS Expansion site has been impacted on by illegal dumping and the deposition of fill material. The extent of wetland that occurs beneath these areas is unknown. • Water quality. The impacts on surface water quality re discussed in detail in the J&W surface water specialist study (JW090/19/6007-24). In summary the following constituents were raised as elements of concern in relation to the SANS 241:2015 Drinking Water Standards and/or the 2017 RWQO for IUA 1, Resource Unit 1_7 as determined by DWS: Electrical conductivity (EC), Manganese (Mn), Chloride (Cl), Sulfate (SO4), Boron (B), Fluoride (F), Sodium (Na), Ammonia (N) and Ortho- Phosphate (P), E. coli and Total Coliforms. The main services supplied by the wetland HGM Units are the indirect benefits related to water quality enhancement and flood attenuation. This is largely due to the extent of vegetation cover present, specifically in the Unchannelled valley bottom system. As mentioned previously, the type of vegetation cover present in this HGM Unit and in Seep 2 has been altered due to the change in hydrological regime (more seasonal to permanent wetland system) and extent in the HGM Unit which has been increased in size due to the point source discharge of stormwater into the system. Opportunity to provide the service is also in many cases high due to the upstream catchment and the quality of stormwater entering the site. The maintenance of biodiversity is supplied at an Intermediate level mainly due to the rare wetland type and level of protection of the wetland HGM Units. At a quaternary catchment scale, the A21C catchment has a Moderate Ecological Importance and Sensitivity (EIS). At a local scale, the EIS was assessed for the three HGM units (Seep, Un-channelled Valley Bottom and Channelled Valley Bottom). The Seep 1 - Moderate overall EIS and Seep 2, Unchannelled valley bottom and the channelled valley bottom – High overall EIS. Way Forward Taking into consideration the current impacts present on site and the mitigation measures proposed, the soils and wetland specialists are of the opinion that if the proposed mitigation measures for the Phase 1A expansion are successfully implemented including the mitigation measures proposed in the surface water, groundwater, aquatic and biodiversity assessments, the project will have an Insignificant and Very Low impact on the soils and the downstream wetlands respectively. In line with the mitigation hierarchy and the initial project discussions held between GDARD and the EAP, the main mitigation measure for Phase 1B is to have no net loss in wetland functionality and therefore to ensure that the footprint for Phase 1B is reduced in size to not be located within the wetland area.