Project UR1335: Corridors of Freedom Sewer Upgrades: Turffontein

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1 Project UR1335: Corridors of Freedom Sewer Upgrades: Turffontein FEBRUARY 2018 Prepared by: Abaziyo Consulting Engineers cc P O. Box 5672 Halfway House 1685 Tel. (011) /1/2/3/4 Fax. (011) Prepared For: 2107 Johannesburg Water 17 Harrison Street Johannesburg P O Box Marshalltown

2 OVERVIEW The stormwater management plan is aimed at reducing flood damage, including damage to life and property; minimizing increase in stormwater runoff; reducing soil erosion; and other in-stream structures caused by the upgrade of the outfall sewer and enhancing the positive effects of the upgrade. The inception of the stormwater plan considers the aims of the following Legislative Framework: (i) National Water Act (Act 36 of 1998)- To provide for the fundamental reform of the law relating to water resources and to provide for matters connected therewith. (ii) Conservation of Agricultural Resources Act (Act 43 of 1983)- To provide for the control over the utilization of the natural agricultural resources in the Republic in order to promote the conservation of the soil, the water resources and the vegetation and the combating of weeds and invader plants. (iii) Environment Conservation Act (Act 73 of 1989) -To provide for effective protection and controlled utilization of the environment. (iv) Health Act (Act 63 of 1977)-To provide for measures for the promotion of health of the inhabitants of the Republic. (v) Atmospheric Pollution Prevention Act (Act 45 of 1965)-To provide for the prevention of pollution of the atmosphere. The primary objective of the stormwater management plan for this project is to ensure that natural features, such as trees, rivers and wetlands, etc. are preserved whenever possible, and that care is taken to preserve selected trees to enhance soil stability and landscaped treatment of the area. The identified possible negative effects are mitigated through the proposed mitigation strategies to ensure that the environment is protected and conserved. Below is the list of the possible actions from construction or operation that could have a negative impact on the environment. The degree of likelihood of the action is derived from the observations made from previous projects. The mitigation/management strategies will be implemented by the identified persons involved on the different phases of the project. 2

3 PROJECT LOCATION AND DESCRIPTION The proposed works are located in Turffontein, approximately 7 km south of Johannesburg CBD in Gauteng Province of South Africa. The area is bound by Riffle Range Road on the South and Kliprivier Road on the East. Turffontein suburb falls within the Klipspruit Sewer Basin. It drains in a south western direction towards the Olifantsvlei WWTW. The project entails the replacement of existing 150mm, 200mm and 250mm diameter clay sewer pipes, 150mm and 200mm diameter concrete pipes with HDPE pipes of diameters ranging from 160mm to 400mm diameters of class PE 80/PE100 and installation of new sections of 200mm diameter HDPE pipes. There are planned future Corridors of Freedom Developments. The scope and extent of these developments is not yet known. 3

4 CONSTRUCTION PHASE Action Impact/s Likelihood of occurrence Mitigation/Management Strategies Person/s responsible for implementing strategies Soil erosion Loss of backfill material if erosion happens prior to backfill (Runoff can wash away loose soil). Curly formation along pipeline route. Likely Execute the work within a short space of time. Compact adequately the backfill material. Backfill to the same level as the existing ground. Revegetate disturbed ground. Engineer and contractor Disturbance of Threatened Ecosystem Disturbance of the biodiversity in the project area. Removal of plants on the pipe route and edge of the stream embankment. Likely Reinstatement of original vegetation as much as possible. Ensure that there is little disturbance of the environment. Do not introduce any foreign species in the project area. Wherever possible, relocate any endangered species. Rehabilitation and or installation of new gabions. Contractor, Employer and Engineer

5 Action Impact/s Likelihood of occurrence Mitigation/Management Strategies Person/s responsible for implementing strategies Concentration of stormwater runoff at different locations along pipe route due to disturbance of the natural ground slopes. Ingress of soil in to stream due to the construction of gabions. Create pools which may be a hazard to the community/ residents. Unlikely Backfill to natural ground. Engineer and Contractor Silting Unlikely Contractor will be instructed to create a barrier using sand bags to block any possible movement of soil into the stream. Engineer and Contractor 5