e r 2 - Umgeni Water

8.4.2 Bulk Water Supply Infrastructure Constraints and Requirements| Bulk Potable Water Supply Plan ChapterThis section describes the more significant constraints within Umgeni Water’s existing bulk supply infrastructureand the proposed infrastructure development plans to overcome these constraints and provide the additionalcapacity required for further expansion of the existing supply ‘footprint’ area. The proposed water supplyinfrastructure links directly to the proposed water resource infrastructure discussed in Chapter 7.Inland RegionOver recent years the eThekwini Metropolitan Municipality has put considerable effort into optimising theoperation of its distribution systems that are served by the Lower Mgeni System. Amongst other things, this hasled to the municipality implementing new infrastructure in order to undertake a significant load shifting exercise.The municipality’s western aqueduct development, which is expected to be fully commissioned in mid-2013, willrepresent the most significant of these load-shifting operations. The intention is for those areas currently beingserved under pumping from the Lower Mgeni System (namely, from Durban Heights Water Treatment Works) tobe transferred onto the Upper Mgeni System, to be served under gravity from Midmar Water Treatment Works viathe western aqueduct. Further to this, eThekwini Metropolitan Municipality plans to link the western aqueduct toits northern aqueduct thereby extending this supply to the municipality’s northern areas as far as the Dube TradePort development zone. Whilst this measure will free up additional capacity within the Lower Mgeni System thatcan be redirected elsewhere within the Municipality, it places considerable additional load on much of UmgeniWater’s infrastructure in the Upper Mgeni System, including the ’57, ’61 and ‘251 Pipeline systems, Midmar WaterTreatment Works, and ultimately on the water resources available from Midmar Dam. The recent augmentation ofthe ’57 Pipeline by Umgeni Water was undertaken in order to provide sufficient capacity in this portion of thesupply network to meet the required demands of the western aqueduct.Once Phase 2 of the Mooi-Mgeni Transfer Scheme (MMTS-2) has been commissioned in 2013, the 99% assuredyield of the Mgeni System at Midmar Dam will increase from 322 500 cubic metres per day to 476 200 cubic metresper day. However, even an increased yield at Midmar Dam will be insufficient to support the imposition of theproposed full Western Aqueduct load shift for any significant period of time, and further water resourcedevelopments will be required. One water resource option that is to be investigated by DWA is the MkomaziWater Project which would transfer raw water from the Mkomazi River to a Water Treatment Works in theadjacent catchment, with potable water then being supplied to the Umlaas Road area to feed into the ’57 Pipelineand subsequently into the western aqueduct. The Mkomazi Water Project is currently only entering the detailedfeasibility investigation stage and therefore the very earliest that it is envisaged that the scheme could becompleted and operational is 2024. Refer to discussion in Chapter 7 of this Business Plan.With Midmar Dam’s yield then being fixed after MMTS-2, it is deemed prudent that all future bulk distributioninfrastructure upgrades within the Upper Mgeni System (Midmar Water Treatment Works - Umlaas Road) belimited to the water resources capacity that Midmar Dam can support (bearing in mind that Midmar Dam mustalso contribute to the water resource requirements downstream of it). Hence, the water available to meetdemands downstream of Umlaas Road Reservoir is limited until such time as the Mkomazi Water Project iscommissioned. Further to this, the available water will decrease over time as the demands upstream of the UmlaasRoad Reservoir increase.In order to meet the anticipated load shift in demand by eThekwini Metropolitan Municipality from the LowerMgeni System to the Upper Mgeni System, the following Umgeni Water infrastructure projects will be required:• Upgrade of Midmar Water Treatment Works;• Augmentation of the ’61 Pipeline from ED2 to Umlaas Road together with an upgrade of the Umlaas RoadReservoir.Umgeni Water Five-Year Business Plan | 2011/2012 to 2015/2016 Page 49