Heritage Cases

Proposed Vutshini - Nkandla water scheme (North) Phase 1: Pipeline P1-1, Nkandla Local Municipality, KwaZulu-Natal

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The King Cetshwayo District Municipality (KCDM) is planning to construct the proposed Vutshini-Nkandla Water Scheme (North) located north of the settlement of Qudeni, within Wards 3, 4, and 10 of the Nkandla Local Municipality.The proposed water scheme is aimed at providing potable water to rural communities within this region and will require the construction of a water abstraction works, on the Nsuze River, and a water treatment works. From the water treatment works, water will be pumped through rising mains (internal diameter not exceeding 300 mm) to reservoirs (not exceeding 3 Ml) before being distributed through gravity mains (internal diameter not exceeding 200 mm) to smaller reservoirs close to the targeted communities. From these reservoirs, water will be supplied to the communities through a reticulation network with pipes not exceeding 100 mm in size. Due to the overall size of the proposed water scheme, construction has been divided into a number of phases, with Phase 1 being the most urgent to be implemented, followed by Phases 2, 3 and 4.

Expanded_Motivation: 

The proposed Vutshini-Nkandla Water Scheme (North) project will include the following project components:  Water abstraction from the Nsuze River and the construction of a water treatment works. (This component of the water scheme will be dealt with in a separate Environmental Impact Assessment which is scheduled to commence as soon as the necessary funding is available and makes up Phase 4 of the Water Scheme (North)).  Rising Mains. Water will be pumped from the water treatment works through rising mains (internal diameter not exceeding 300 mm).  Storage Reservoirs and Pump Stations. Five storage reservoirs (not exceeding 3 Ml) will be constructed during Phases 1 and 2 of the water scheme.  Gravity Mains. Water will be distributed from the reservoirs through gravity mains (internal diameter not exceeding 200 mm) to smaller reservoirs close to the targeted communities.  Reticulation Network. Water will be supplied from these reservoirs to the communities through a reticulation network with pipes not exceeding 100 mm in size.  The provision of electricity to the three pumps stations (22 kV) and some of the reservoirs. VUTSHINI - NKANDLA WATER SCHEME (NORTH) PHASE 1: PIPELINE P1-1 Phase 1 of the proposed Nkandla-Vuthini Water Scheme (North) consists of two individual pipelines connecting the storage reservoirs and pump stations. Each pipeline, together with its associated infrastructure (reservoirs, pump stations) will require a separate environmental authorisation via a Basic Assessment. This Basic Assessment Report deals solely with the Vutshini-Nkandla Water Scheme (North) Phase 1: Pipeline P1-1. Pipeline P1-1 of the Vutshini-Nkandla Water Scheme (North) comprises the following components:  Pump station PS1-1 with a footprint of 45 m2.  Reservoir 1-1 near pump station PS1-1 with a capacity of 1 ML.  A 250 mm rising main from pump station PS1-1 to reservoir R1-2.  Reservoir 1-2 with a capacity of 500 kl. The development of the proposed Vutshini-Nkandla Water Scheme (North): Phase 1, Pipeline P1-1 is subject to the provisions of the National Environmental Management Act, 1998 (NEMA) (Act No. 108 of 1998) and the current Environmental Impact Assessment (EIA) Regulations (effective 08 December 2014 as amended in April 2017). The competent authority for this project is the KZN Department of Economic Development, Tourism and Environmental Affairs (DEDTEA). Design alternatives Alternative water sources The proposed bulk water scheme will be supplied via a water abstraction works on the Nsuze River. (The development and construction of the proposed water abstraction works and its associated infrastructure will form part of Phase 4 of the Vutshini-Nkandla Water Scheme (North) and will be dealt with in a separate Environmental Impact Assessment). Alternative water sources that were investigated for supplying this phase of the project included the Mathole, Mkulu and Ndikwe streams; however, as these water sources are tributaries of the much larger Nsuze River, they do not have sufficient water to supply the targeted areas. Additional larger rivers, such as the uMhlathuze River to the south-east and the Buffalo Rivier in the north-west were also explored; however, their geographic location and distance to the targeted communities would make the development financially unviable. Therefore, the proposed project area does not have a reliable alternative to a water abstraction works on the Nsuze River, making it the only viable long-term water source for this scheme. Route alignments When selecting the route alignments for the proposed water scheme, the following criteria were taken into account by the engineering team to find the most practical and cost effective alignments:  The placing of the pipelines close to and along existing roads and tracks.  Following contours.  Following of ridge lines, aimed at limiting impacts on wetlands and sensitive environments. The Vutshini-Nkandla Water Scheme (North): Phase 1, Pipeline P1-1 will include the construction of a bulk rising main pipeline that will connect the two reservoirs, viz. R1-1 and R1-2 and the pump station near the proposed site of the water treatment works. The topography of the supply area varies from flat and undulating grassy hills to steeper rockier surfaces. The irregular surface of the supply area will generate very high pressure heads in the transfer of water to each supply reservoir, therefore, the pipelines will as far as possible follow existing roadways and tracks (which are mostly along contours avoiding steep slopes). Where this is not possible, the pipelines are to follow ridge lines and contours to reduce the steep drops which cause high pressure heads within the pipes. Engineering considerations Alternative materials are limited given that the pipelines have to conform to set design parameters. As such, the following materials will be used for the project:  Bulk Mains. The KCDM has stipulated that ductile iron pipes be used for all bulk mains.  Reticulation Mains. Pipe materials selected for these pipelines have taken into account water pressures, ground conditions and topography. The in situ and operational requirements will guide the selection of materials for these pipelines. Pipelines Based on the preliminary design, it was established that the cost saving on an above ground pipeline is very minor and, therefore, the pipeline has been designed as an underground service. Where possible, trench excavation, pipe bedding and trench backfilling will be undertaken by hand in order to maximize employment opportunities, with labour recruited from local communities within the Nkandla Local Municipality. The buried sections of the pipeline will be approximately 1 - 2 m below the restored ground level. Only air valve chambers (at each high point), scour valve chambers (at each low point) and pipeline marker posts (at bends) will be visible. The concrete chambers will be approximately 2 x 2 m square and will protrude about 500 mm above ground. Construction servitude The construction servitude will be up to 10 m wide in unrestricted areas and down to 5 m in restricted/sensitive areas. An operational servitude of 5 m will be maintained with a servitude agreement that prohibits the construction of permanent structures within the servitude. Also, the servitude must be kept free of trees and woody vegetation. Subsistence agriculture, grazing and grasslands will be permitted over the pipeline servitude. Construction camp A construction camp (approximately 0.5 ha in size) will be required for the duration of the construction period to house administrative offices, construction plant and material stockpiles, fuels, storage facilities and security. Construction workers will not be accommodated at the construction camp. The contractor will identify the exact location of the construction camp prior to construction. The site for the proposed construction camps must be approved by both the Project Engineer and the Environmental Control Officer (ECO). During construction, potable water will be trucked in from the Nkandla Local Municipality and electricity will be supplied by Eskom. A suitable number of chemical toilets will be provided on site for construction staff. Solid waste will be collected onsite and regularly transported to the nearest municipal waste transfer station. Pipe storage yards Pipe storage yards (0.25 ha) will need to be established at regular intervals (1 or 2 km apart) along the pipeline servitude following approval from the Project Engineer and ECO. No pipe storage yards will be permitted within sensitive areas along the pipeline servitude. The location of pipe storage yards along the pipeline route will be negotiated by the contractor with the affected land users. The pipe storage yards will need to be cleared of woody vegetation and there will be, at the most, three tiers of pipes per stack in the yards. Pipe storage yards serve as a convenient place for trucks to load and offload materials; in addition, the yard must provide sufficient space for trucks to turn around. From within the pipe storage yards, the contractor will move the pipes to the side of the trench as required. Each pipe storage yard will be used only until that particular section of pipeline is completed. Pipe storage yards no longer required will be rehabilitated on a progressive basis during construction. Access Most of the alignment is accessible via existing roads and tracks and maximum use will be made of existing access roads. However, during construction, it may be necessary to construct temporary access roads, the majority of which will fall within the construction servitude. The roads will comprise a simple, single lane track immediately alongside the trench and will be cleared and roughly leveled for vehicular access. Temporary access roads will have to be identified with the assistance and approval of the ECO to avoid infringing on sensitive areas. The temporary access tracks will be rehabilitated on a progressive basis during construction. Earthworks and pipe laying Construction activities will require earthworks involving the use of light to intermediate earthmoving machinery and manual labour. The buried sections of the pipeline will be approximately 1 - 2 m below the restored ground level. Therefore, it is anticipated that the excavated trench will be between 1.5 and 2 m deep. The pipeline will be constructed with the ‘dig and lay’ method where pipes are progressively laid and backfilled. This method ensures that the excavated trench is not left uncovered for extended periods of time, thereby avoiding soil erosion. Heavy machinery and earthmoving equipment, such as cranes and back actors, will also be used during construction. However, in sensitive areas pipes will be laid using primarily manual labour. The pipes will be bedded on imported river sand sourced from licensed sand mining operations and backfilled with excavated material. The excavated soil will be stockpiled within the construction servitude during the construction period. The construction method to be utilized will aim to minimize the time that trenches are left open and as sections of the pipe are laid, the trench will be backfilled. Ideally, trenches will remain open for a maximum of four days before being backfilled. Open trenches will be suitably demarcated and signage will be erected to warn local residents of potential dangers. Watercourse crossings Watercourses will be crossed with an open cut trench through the stream, with the pipes buried sufficiently deep not to interfere with the backfilled stream bed. The pipes will be laid with a low point (and scour valve) immediately to one side of the watercourse/drainage line so that the pipe crown is approximately 500 mm below the natural invert of the watercourse. If this pushes the pipes too deep (> 2 m), the pipes will be concrete encased so that the top of the encasement is at the natural watercourse invert. If necessary, gabions will be used to stabilize each side of the watercourse. During construction, it is likely that the contractor will fill in the watercourse to be crossed (using soil from trench excavations), and then a trench will be dug. Excavation will be selective to ensure that the topsoil is placed back on top. Once the pipes have been laid, the watercourse will be returned to its original profile. It should be noted that the construction of the pipeline through the watercourses will not permanently alter the bed, banks, course or characteristics of watercourses/wetlands as the pipeline will be installed below the watercourse invert and the general profile of the affected section of watercourse will be restored to its preconstruction state. Once construction is complete, the land will be rehabilitated according to the specifications of the EMPr. Operation The final operational servitude will be 5 m wide, with a service agreement prohibiting the construction of permanent structures, and the planting of trees or woody vegetation. Subsistence agriculture, grazing and grasslands will be permitted over the pipeline servitude. The pipeline may at times require scouring, meaning that the pipeline will be emptied to allow repairs on the pipeline to be done and to remove any sediment which accumulates in the pipes. A portion of the pipeline will be emptied into a low-lying area or stream. The water being released during scouring will have been treated and, therefore, is not considered effluent. However, erosion protective measures will be installed where required.

ApplicationDate: 

Monday, April 15, 2019 - 15:59

CaseID: 

13727

OtherReferences: 

Dept CaseReference DueDate FinalDecision
AMAFA n/a 08/05/2019

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