I P E L I N E : M I D M A R I D M A R D A M T O M I D M A R

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1 7. 4 M G E N I G E N I S Y S T E M R A W A W W A T E R P I P E L I N E Planning No Project No. Project Status Design (as at January 2011) I P E L I N E : M I D M A R I D M A R W T P I D M A R D A M T O M I D M A R Project Description The Midmar Water Treatment Plant (WTP) draws raw water from Midmar Dam. Water from the dam is supplied under pumping via the 251 Pipeline. The 251 Raw Water Pipeline is a single, mm OD (1 544 mm ID), cement-lined, steel pipe consisting of two sections. The first section, from the dam outlet works to the raw water pump station is approximately 550 m long. The second section, from the raw water pump station to the water works is approximately 2 450m long. The Midmar WTP currently has a design capacity of 250 Ml/day and is scheduled to be upgraded to 375 Ml/day in the near future (Section 7.4.2). Three pump sets are currently installed in the raw water pump station (2 duty + 1 standby). A fourth pump set is to be installed along with the Midmar WTP upgrade. With the WTP upgrade to 375 Ml/day, flow velocity in the single raw water pipeline will increase to 2.3 m/s. Being the only raw water supply into Midmar WTP, this pipeline is a strategic asset and its overall risk rating is thus high. DWA has modified the Midmar Dam outlet works and pipework to provide a second outlet pipeline and cross-connections at the dam wall. This intervention has minimised the risk of failure of the dam outlet works. Umgeni Water must now ensure that the overall risk of the raw water transfer between the dam and the Midmar WTP is mitigated by providing a second raw water transfer pipeline between the outlet and the WTP (Figure 7.6). 345

2 Figure 7.6 General layout of the 251 Raw Water Pipeline: Midmar Dam Outlet to Midmar WTP. 346

3 Key information on this project is summarised in Table 7.6. Table 7.6 Project information: 251 Raw Water Pipeline from Midmar Dam to Midmar WTP. Project Components: Capacity: Raw water pipeline from dam outlet to Midmar WTP and fourth raw water pump. 375 Ml/day Institutional Arrangements The new infrastructure will be owned, operated and maintained by Umgeni Water. Beneficiaries The scheme will serve the 61 System which supplies potable water to umngeni, The Msunduzi, Umgungundlovu and ethekwini Municipalities. Implementation The project will be constructed over two years and is estimated to cost R 110 million at 2010 prices. 347

4 M I D M A R I D M A R W A T E R T R E A T M E N T P L A N T Planning No Project No. Project Status Design (as at January 2011) Project Description The Midmar Water Treatment Plant (WTP), which was commissioned in 1996, draws raw water from Midmar Dam. Water from the dam is supplied under pumping via the 251 Pipeline. The Midmar WTP has a design capacity of 250 Ml/day and is currently operating at an AADD of around 177 Ml/day, with daily peaks of up to 300 Ml/day. With the imminent implementation of the load transfer of the Western Aqueduct demand onto the Upper Mgeni System, it is necessary to upgrade the capacity of Midmar WTP. The WTP should be upgraded to 375 Ml/day so that the combined capacity of the Midmar WTP and D.V. Harris WTP will utilise the maximum yield (at a 99% assurance level) available from Midmar Dam once the MMTS-2 has been commissioned. The design of Midmar WTP fortunately lends itself to an upgrade to 375 Ml/day without major civil construction, as the clarifiers were already upgraded to this capacity during Such an upgrade is expected to include the design, installation and commissioning of a new filter plant, sludge plant centrifuge and outlet works (Figure 7.7). Key information on this project is summarised in Table 7.7. Table 7.7 Project information: Midmar WTP Upgrade. Project Components: Capacity: WTP capacity upgrade from 250Ml/day to 375Ml/day (design, installation and commissioning of a new filter plant, sludge plant centrifuge and outlet works). 375Ml/day. 348

5 Figure 7.7 General layout of the Midmar WTP Upgrade project. 349

6 Institutional Arrangements The Midmar WTP is situated in umngeni Municipality. Umgeni Water will own, operate and maintain the upgraded Midmar WTP and will sell potable water from this system to the Msunduzi Local Municipality, ethekwini Municipality and Umgungundlovu District Municipality as per existing bulk water supply agreements. Beneficiaries The scheme will serve the 61 System which supplies potable water to umngeni, Msunduzi, Umgungundlovu and ethekwini Municipalities. Implementation The project will be constructed over four years and is estimated to cost R 230 million at 2010 prices. 350

7 H O W I C K - N O R T H O R T H R E S E R V O I R U P G R A D E Planning No Project No. Project Status Design (as at January 2011) Project Description Howick s northern suburbs are currently served by three storage reservoirs situated at the old Howick WTP Complex (Eridene Road). Water treated at Midmar WTP is pumped from Mill Falls Pump Station and is discharged into Howick-North Reservoir 3. Water then runs under gravity to the remaining two reservoirs, namely Reservoir 1 and Reservoir 2 (Table 5.7). Howick is currently undergoing a sustained period of housing development growth (Section 2.5), which has led to an increased demand for water (Section 3.3.3). Furthermore, new developments are currently being implemented, or are planned, for sites located above the command elevation of Howick North s reservoirs. Interim measures are currently being put in place by developers to boost pressure to supply such developments. However, Umgungundlovu District Municipality will need to construct a new reservoir at a higher level to serve these new developments in the long-term. With the required high level reservoir, the Howick-North Reservoir Complex will serve as a distribution reservoir that should have 36 hours for reticulation demand and 15 hours balancing storage. The determination of the storage requirement at Howick Reservoir is indicated in Table 7.8. Table 7.8 Storage Requirement at Howick-North Reservoir Complex. Reservoir Function Demand (Ml/day) Time (hours) Required Storage (Ml) Reticulation Distribution TOTAL STORAGE REQUIREMENT 13.0 The current storage of 6.6Ml needs to be increased with a new 6.5 Ml reservoir. Key information on this project is summarised in Table 7.9. Table 7.9 Project information: Howick-North Reservoir Upgrade. Project Components: Capacity: New Reservoir 6.5 Ml 351

8 Figure 7.8 General layout of the Howick Reservoir Upgrade. 352

9 Institutional Arrangements The new Howick-North Reservoir will be owned, operated and maintained by Umgeni Water. Beneficiaries The upgrade to Howick-North Reservoir will benefit consumers in the Howick North area of umngeni Municipality. Implementation The construction duration of this project is anticipated to be one year. The total cost of this project is estimated to be R 12 million at 2010 prices. 353

10 H O W I C K - W E S T E S T R E S E R V O I R U P G R A D E Planning No Project No. Project Status Detailed Feasibility (as at January 2011) Project Description Potable water is supplied to the Howick-West Reservoir Complex from Midmar WTP via the Mills Falls Pump Station along a 700 mm NB diameter steel pipeline. The current total storage capacity at the Howick-West Reservoir Complex is 16.5 Ml and serves as the distribution node for the supply area as shown in Figure 7.9. Water is then pumped from the Howick-West Reservoir Complex to Mpophomeni and Groenekloof Reservoirs via the Howick-West Pump Station along 250 mm NB and 600 mm NB diameter steel pipelines respectively. The Groenekloof Reservoir Complex, with a current total storage capacity of Ml, serves as a further distribution node from where the water is pumped to the Greater Vulindlela area and gravity-fed to the Sweetwaters and Blackridge terminal reservoirs. The progressive Annual Average Daily Demand (AADD) off the Howick West Reservoir Complex was 34 Ml/day as at October This, in relation to the current storage capacity of 16.5 Ml at the Howick West Reservoir Complex, amounts to a total storage capacity of 6 hours. The umngeni Local Municipality is in the process of implementing a low-cost housing development in the Mpophomeni supply area and middle to high-income residential development in the Garlington area. These proposed developments, combined with the natural growth of the Howick-West Supply System, will place undue stress on the Howick- West Reservoir Complex to sustain the projected demand. To sustain the current and future demand off the Howick-West Reservoir Complex, it is necessary to augment the existing storage capacity at the Howick West Reservoir Complex with an 8.5 Ml reservoir. 354

11 Figure 7.9 General layout of the Howick-West Reservoir Upgrade. 355

12 Key information on this project is summarised in Table Table 7.10 Project information: Howick West Reservoir Upgrade. Project Components: Capacity: New reservoir 8.5 Ml Institutional Arrangements The new Howick-West Reservoir will be owned, operated and maintained by Umgeni Water. Beneficiaries The upgrade to Howick-West Reservoir serves as a balancing reservoir that will indirectly serve Vulindlela, Blackridge and Sweetwaters in The Msunduzi Municipality and Mpopomeni and Hilton in the umngeni Municipality. Implementation The construction duration of this project is anticipated to be one year. The total cost is estimated to be R 22 million at 2010 prices. 356

13 G R O E N E K L O O F R O E N E K L O O F R E S E R V O I R U P G R A D E Planning No Project No. Project Status Planning (as at January 2011) Project Description The Groenekloof Reservoir serves as a balancing reservoir for Vulindlela, Sweetwaters and Blackridge (Figure 7.10). The current demand out of Groenekloof Reservoir is 21 Ml/day. This demand is expected to increase to 34 Ml/day by 2030 when 24 Ml of storage will be required. The current capacity of the reservoir is 17 Ml. The reservoir capacity will be over allocated by An additional 6 Ml storage will then be required. Key information on this project is summarised in Table Table 7.11 Project information: Groenekloof Reservoir Upgrade. Project Components: Capacity: New 6 Ml reservoir. 6 Ml. Institutional Arrangements The new reservoir will be owned, operated and maintained by Umgeni Water. Beneficiaries The upgrade to Groenekloof Reservoir will benefit consumers in the umngeni and the Msunduzi municipalities. Implementation The construction duration of this project is anticipated to be one year. The total cost is estimated to be R12 million (2010 costs). 357

14 Figure 7.10 General layout of the Groenekloof Reservoir Upgrade. 358