Environmental Assessment for the Kuiseb Delta New Scheme
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ENVIRONMENTAL ASSESSMENT FOR THE KUISEB DELTA NEW SCHEME BACKGROUND INFORMATION DOCUMENT 1 THE PURPOSE OF THIS DOCUMENT The purpose of this Background Information Document (BID) is to inform Interested and Affected Parties (I&APs) and authorities about an Environmental Scoping Assessment (ESA) (hereafter referred to as the Study) being undertaken for the Kuiseb Delta New Scheme (hereafter referred to as the Project) situated near Walvis Bay in the Erongo Region. Besides supplying information about the Project, this BID also provides an opportunity for I&APs and authorities to register their interest with the Environmental Assessment Practitioner (EAP) and to submit comments/questions/concerns they may have. Such comments/questions/concerns will ensure that all the issues of relevance to the Project are evaluated as part of the ESA. 2 BACKGROUND1 2.1 THE SCHEME The central portion of the Namib area, i.e. Namib Water Supply Area, is partially supplied by means of water from the Kuiseb Delta aquifer, in specific from the Dorob South and the Rooibank B aquifers (see Figure 1). Water is also supplied from the Dorop North aquifer, but does not form part of the Kuiseb Delta scheme, i.e. does not form part of this study. The Kuiseb Delta Scheme consists of various aquifers, boreholes, pump stations with pump lines, gravity pipelines and reservoirs supplying water to the town of Walvis Bay and surrounding customers, predominantly mines. 1 Information obtained from BID No. SC/RP/NW/011-2019. 1 BACKGROUND INFORMATION DOCUMENT - KUISEB DELTA NEW SCHEME – MAY 2019 ____________________________________________________________________________ Figure 1: Central Namib Area Regional Water Supply indicating the Study Area (i.e. Proposed Pipelines) 2 BACKGROUND INFORMATION DOCUMENT - KUISEB DELTA NEW SCHEME – MAY 2019 ____________________________________________________________________________ Water from Dorop South and Rooibank B aquifers, is pumped to the 2,000m3 concrete High Dune Reservoir, from where it flows under gravity via a 9,100m long, 350mm fibre cement (FC) pipeline to the Mile 7 Reservoir in order to supply Walvis Bay. The Rooibank B boreholes, pump directly into the gravity feed pipeline connecting High Dune and Mile 7 reservoirs (See Figure 1 for orientation). Electricity is supplied via an underground power cable. 2.2 CHALLENGES Parts of the Scheme’s infrastructure dates back to as early as 1962, which has resulted in various challenges to maintain. As a result, water supply to NAMWATER’s customers has been interrupted on several occasions, which has a variety of socio-economic implications. The demand for water has also increased to a level above the current infrastructure’s capacity. Maintenance of the old pipeline (fibre cement) and the power cable is complicated by moving sand dunes, which has resulted in delaying repairs and resulting interruption in supply of water to the town of Walvis Bay and surrounding customers. The power cable is often covered by sand dunes of such magnitude, which make access to the cable impossible. 2.3 NEED FOR THE PROJECT Upgrading and expansion of this Scheme has become necessary mainly due to (i) an increase in the demand for water from current customers and projected future demands, and (ii) redundant and outdated infrastructure, which results in an inability from the side of NAMWATER to ensure security of water. 2.4 NEED FOR THE STUDY The construction of water supply pipelines and electricity lines are listed activities (GN. No. 29 of 2012) requiring an Environmental Clearance Certificate (ECC) before being implemented (section 27(3) of the Environmental Management Act, No. 7 of 2007). Urban Green cc has accordingly been appointed by NAMWATER to apply for an ECC and undertake the environmental assessment, as specified by the Environmental Impact Assessment Regulations (GN. No. 30 of 2012). 3 BACKGROUND INFORMATION DOCUMENT - KUISEB DELTA NEW SCHEME – MAY 2019 ____________________________________________________________________________ 3 PROJECT DESCRIPTIONii 3.1 OVERVIEW NAMWATER proposes to (i) increase the amount of water abstracted from the Dorob South and the Rooibank B aquifers, and (ii) upgrade the associated water supply infrastructure, to ensure security of water supply to Walvis Bay town and the other customers. For this purpose - (i) Seven (7) of the eighteen (18) drilled boreholes will be commissioned, of which five (5) of the mentioned seven (7) will be production boreholes and two (2) of the mentioned seven (7) will be standby boreholes; (ii) A new route, overhead powerline and HDPE pump pipeline to the total length of 8.8 km will be constructed to connect the newly drilled seven (7) boreholes and the existing thirteen (13) boreholes to the existing scheme; (iii) The existing 9.1 km gravity pipeline (fibre cement) between the High Dune- and Mile 7 Reservoirs will be replaced with a below ground HDPE pipeline following the old pipeline route. Since the existing pipeline is too deep to access, the AC pipes will be left in-situ; and (iv) Re-grading and maintenance of the existing route between High Dune- and Mile 7 Reservoirs. 3.2 LOCALITY The Kuiseb Delta, comprising of the Dorob South and the Rooibank B aquifers, lies to the south- east of Walvis Bay and forms part of the Kuiseb River (see Figure 1 above). 3.3 INFRASTRUCTURE DESIGN AND SPECIFICATIONS All the infrastructure to be provided, i.e. pipeline, powerlines and route will follow the same alignment. Underground Pipelines All new pipelines will be HDPE (high-density polyethylene) pipes of different diameters, i.e. 125mm (1,7km), 200mm (2,5km), 315mm (8.6km), 400mm (1,7km) and 500mm (1.9km). ii Information obtained from BID No. SC/RP/NW/011-2019. 4 BACKGROUND INFORMATION DOCUMENT - KUISEB DELTA NEW SCHEME – MAY 2019 ____________________________________________________________________________ The trench within which the pipelines will be placed will be 1.3m in depth and 1.15m in width. Overhead Powerlines: For purpose of supplying electricity to the various boreholes and pump station, a 66kV-400V overhead power lines are intended. The powerline will consists of freestanding tar pole structures at a height of 14m, which might be increased to a height of 20m at certain sections to ensure a safe height above the migrating sand dunes. The span with between the pole structures is expected to be 80 to 100m, but is expected to differ at bends. A three-phase electrical system will most likely be installed – i.e. 3 conductors. The required servitude for the proposed power lines will be 22m – i.e. 11m either side of the power line centreline. Routes: Access routes will be ‘constructed’ for exclusive use by NAMWATER. These ‘roads’ will be 5m in width and will NOT be for public use. 4 THE RECEIVING ENVIRONMENT The Project area, as reflected by Figure 1 above, is characterised by relatively flat topography with sand dunes of different heights and extend. Some parts of these sand dunes are known to migrate and does not stay constant. The Kuiseb Delta New Scheme pipeline is situated within an area which generally descends from east to west towards the coastline. The Project area is situated within the Namib Desert, an environment that can be classified as arid. This environment receives less than 50 mm of rainfall annually, but receives additional precipitation in the form of fog, which is a common feature of this environment. The physical geography of receiving environment can generally be divided into two components, namely, the inland dune fields to the west and north-west, and the gravel plains east wards further inland. The gravel plains have a unique biologically sensitive soil crust that supports several endemic plant species, most notably lichens. These plains because of their proximity to Walvis Bay’s existing built-up area have been subjected, to varying degrees of severity, to habitat disturbance and degradation. The ecologically sensitive Namib Desert supports high levels of biodiversity relative to most arid environments in terms flora and fauna, with significantly high levels of species endemism. Among the faunal species, reptiles, birds and a few invertebrate species are among the most 5 BACKGROUND INFORMATION DOCUMENT - KUISEB DELTA NEW SCHEME – MAY 2019 ____________________________________________________________________________ abundant in terms of diversity and endemism. Overall endemism, abundance of large mammals is regarded as low. The Project falls within both the Walvis Bay Urban- and Walvis Bay Rural Constituencies. The Urban Constituency includes the town of Walvis Bay and surrounding Townlands, which has a relatively high population density – i.e. 1896 people per km² relative to regional density of 2.4 people per km². In 2011, the total population for the Erongo Region was 150,809. The Rural Constituency, which is located within the Dorop National Park, is very sparsely populated. The Project area includes the Southern Topnaar Community or ǂAonin community, having Utuseb as their centre where about 700 people resides. 5 POTENTIAL ENVIRONMENTAL CONCERNS There are several potential environmental impacts (i.e. both biophysical and social in nature) that have already been identified to date. As the EA process progresses the identification of additional impacts can be expected. These impacts relate to the planning, construction, operational and decommissioning phases of the Project, which are applicable to both the immediate and larger receiving environment. 5.1 SOCIAL IMPACTS The following potential social impacts (negative and positive) can be expected as part of the Project. Negative: Temporary interruption to the supply of water during the construction phase – i.e. when current pipeline is disconnected and the proposed pipeline is connected. Influx of construction workers. Nuisance impacts (dust and noise). Temporary restriction of movement (e.g. road access). Temporary risk of animals and people falling into open trenches. Temporary waste accumulation. This may include unexpected materials, such as excavated soil that cannot be re-used. Electrocutions by overhead powerlines within areas where migrating sand dunes increase access to electrical overhead cables.