MEMORANDUM Managing Water for Life Date: 15 September 2016

Transcription

1 MEMORANDUM Managing Water for Life Date: 15 September 2016 Subject: WARTBURG TO BRUYNSHILL PIPELINE INFORMATION 1. BACKGROUND Umgeni Water is a Bulk Water Provider to Umgungundlovu District Municipality (DM). As part of a strategy to provide a reliable bulk potable water supply to the municipalities within the KwaZulu-Natal Inland Region, Umgeni Water is investigating the implementation of a pipeline from Wartburg reservoir to Bruynshill reservoir in the area shown in Figure 1. This pipeline would replace existing infrastructure that currently supplies water to the Swayimana area and will ultimately supply the Msilili and Tafamasi areas in the Ilembe District Municipality as well. The current infrastructure supplying water to the Swayimana area is under immense pressure due to the demand exceeding the supply. The Bruynshill reservoirs are drained regularly and this does not allow for the adequate storage for peak times. The Bruynshill pump station supplies 3.3Ml/day to Bruynshill reservoirs, and the outlet meter varies between 3.3 Ml and 3.7Ml/day. The limited supply to the Wartburg reservoirs and the lack of storage capacity also dictates the volume of water available to supply the Swayimana area. The pump station therefore operates only when there is sufficient supply at the Wartburg reservoirs. This results in non-supply to the Swayimana area during certain periods. With the implementation of the umshwathi Bulk Water Supply Project, which recently commenced, the supply to and storage at the Wartburg reservoirs will be increased. This will provide adequate supply to the Swayimana area and the ILembe areas of Msilili and Tafamasi, provided the infrastructure supplying Bruynshill is upgraded.

2 Figure 1: Locality Bruynshill Pipeline

3 Existing Infrastructure The Bruynshill Reservoir is currently supplied by the Bruynshill pump station, which draws its supply from the Wartburg reservoir. The Wartburg reservoir forms part of the DV Harris system and is in turn fed from the Claridge reservoir (Figure 2). The Bruynshill pump station s suction line is a 250mm diameter upvc pipeline approximately 5.8km long. The floor level at the Wartburg reservoir is m and the pump station is approximately 919m AMSL. The delivery line of the pump station is 250mm diameter steel, approximately 3.6km long, and delivers water to Bruynshill reservoir, which has a top water level of m. The delivery pipeline was commissioned in June 2012 and replaced the existing 250mm diameter mpvc pipeline, which could not withstand surge pressures. The existing suction line is gravity fed and routed through two high spots. Under high flows and low reservoir levels, these areas cause negative pressure within the pipeline. This is detrimental to the operation of this infrastructure and restricts capacity. Figure 2: Existing Bruynshill Pipelines and Pump Station

4 2. DEMAND The future demands listed in Table 1 are from report titled Report on Water demand Investigation for Umshwathi Bulk Water Supply area by Royal HaskoningDHV dated 10 February This report is available on request. Population projections over a 30-year period from 2015 using the Census 2011 household counts with an assumed household average size of eight members had been utilised. Population growth rates have been postulated based on observation of present and historical demographic dynamics in the areas. The water projections made below are based on the population using the agreed Water Service Level norms, namely 60l/day average daily consumption per person, plus 30% water loss allowance, a seasonal peak demand factor of 1,25 and a contingency factor of 1,20 to yield 78l/p/d GAADD and 117l/p/d GPDD. Table 1 Water demands rolled up to supply nodes level Medium Growth 2045 Supply Area 2045 GAADD in Ml/day 2045 GPDD in Ml/day MEDIUM Growth Scenario MEDIUM Growth Scenario Swayimana Msilili and Tafamasi Total The Wartburg to Bruynshill pipeline should be designed to the 2045 Gross Peak Daily Demands (GPDD) and the pump station designed to Gross Annual Average Daily Demands (GAADD). 3. PROPOSED INFRASTRUCTURE The existing pipeline system can only supply, under ideal conditions, a maximum of 6.4Ml/day at a velocity of 1.5m/s. This will not meet the ultimate demand of the area of supply. The Wartburg to Bruynshill Pipeline project will provide adequate supply to current and future supply areas and will eliminate non-supply issues at Swayimana. The project will consist of three components:- - Design and construction of a pipeline from Wartburg reservoir to Bruynshill pump station - Design and construction of a pipeline from Bruynshill pump station to Bryunshill reservoir - Design and construction of a pump station near the Wartburg reservoir site 4. DESIGN PARAMETERS Proposed Pipeline from Wartburg reservoir to existing Bruynshill pump station A proposed preliminary pipeline route from the Wartburg reservoir to Bruynshill pump station has been selected (Figure 4). The gravity line begins at the Wartburg reservoir and deviates from the existing route around the town to avoid disruption of the existing services within the town. The new 400mm diameter steel pipeline will connect to the

5 outlet pipework from the new reservoir to be constructed adjacent to the existing reservoir. Provision has been made for this connection in the design of the reservoir layout. Figure 3: Existing and proposed pipeline through Wartburg A proposed new route from the reservoir to the pump station is shown in Figure 3. This new route bypasses the town of Wartburg. Thereafter the new pipeline should be laid next to the existing 250mm upvc gravity main up to the existing pump station. At the pump station the new pipeline will bifurcate to a new 350mm steel pipeline and the existing 250mm steel pipeline (Figure 4). The new 350mm steel pipeline must join the existing 250mm pipeline before the Bruynshill reservoir. All efforts should be made to keep the original system operational throughout the construction process with minimal downtime for interconnection.

6 Figure 4: Proposed pipeline route Proposed New Bruynshill Pump Station The new Bruynshill pump station should be designed to deliver approximately 9.2Ml/day. The installation of the pumps should be done in stages as and when demand requires. Initially two pumps should be installed, one duty and one standby, to deliver approximately 4.6Ml/day each. When the demand exceeds 4.6Ml/day in the future, another pump will be installed to deliver an additional 4.6Ml/day, resulting in two duty and one standby pump. The layout of the pump station and the pipework must cater for the future pump. The pump station position is shown in Figure 3 but a detailed analysis should be carried out to determine the most suitable site and elevation. Pumps should be sized for a 10 year demand with the opportunity to add additional pumps to accommodate up to the 30 year demand. Pumps should be designed to supply the ultimate 30-year demand over 24 hours. 5. PROJECT COSTS The total capital cost for the Wartburg to Bruynshill pipeline and pump station, as estimated by the Project Office. 6. LAND AND GEOTECHNICAL SURVEY Land and Geotechnical surveys were conducted during this study.

7 7. ENVIRONMENTAL Under new regulations (GNR 385, 386, 387), published under the National Environmental Management Act (NEMA) now in effect, the proposed project is a scheduled activity, and Umgeni Water will be required to register this project with the Department of Agriculture and Environmental Affairs (DAEA), who will have to provide final authorization (Record of Decision or ROD) for the project to proceed. A Basic Assessment study will be required in terms NEMA (Act 107 of 1998) and Government Notice: GNR 385 and GNR 386 (1m, 1n and 4) An Environmental Management Plan (EMP) will be required for the construction and operational phases of the proposed pipeline. Public Participation Umgeni Water will be required to liaise with stakeholders (interested and affected parties). It is envisaged that an external public participation consultant will be required for the project and at least one Public Participation meeting will be held for this project. In addition, landowner consultation will have to be undertaken and landowner consent obtained. Based on the outcome of the initial environmental assessment, a terms of reference for both the heritage and other specialist studies will be compiled and tendered. The environmental studies must be completed and environmental authorisation obtained before construction commences. Landowner negotiations and consents should be obtained so that servitudes can be registered on completion of construction. 8. PROJECT PROGRAMME This project should be regarded as urgent and every effort to fast-track to commissioning should be made. Key project milestones Original approved baseline RoD obtained Release of Expenditure for Construction Appoint Environmental Consultants (EIA / ROD) Appoint Design Consultants (PSP) Complete Final Design & Tender Documentation Award of Contract - Pipe Supply Award of Contract - Pipeline & Pump Station Pipe Delivery on Site Construction Start Construction End Feb-15 May-14 Jun-14 Aug-14 Jan-15 Nov-14 Mar-15 Mar-15 Apr-15 Dec-15