Cape Municipalities act to save water
[Paarl Mountain dams]
Cape Town is not alone in its efforts to develop additional sources of water.
The smaller inland municipalities are also supplied by the same 6 main dams that supply Cape Town and (under normal circumstances) they have a combined allocation of some 70 M.cuM of water per annum compared to 400 M.cuM of water allocated to the City and 200 M.cuM for agriculture. Most are augmenting by renovating existing boreholes and drilling additional ones.
To the west, Porterville, Eendekuil, Redelinghuis and Aurora are largely independent through their boreholes and springs, while Picketberg and Veldrif depend upon the Misverstand dam which in turn is filled by the Berg River and therefore depends upon releases from the Berg River dam. Veldrif is planning an own local desalination facility, also covering the fish factory, while Picketberg is planning a local water reclamation facility. Saldanha is planning to drill boreholes into the Langebaan Aquifer in 2018 to reduce dependence upon the Misverstand Dam.
There is a difficulty for Swartland which depends upon the Voelvlei dam because the abstraction point serving them is above the water at anything under 12% of dam capacity. Accordingly, Cape Town is minimising its 10ML/d draw on Voelvlei Dam to just 3-4 days per week to leave as much water in the dam as possible for the western municipalities.
To the north, Drakenstein Municipality are newly promoting the use of reclaimed, so-called 2nd grade water that may be collected by tanker via a metered pump from the Paarl Waste Water Treatment Plant. 2-5 ML/day are available, well priced at R3.99 (excl) per kilolitre, ideal for irrigation and dust control purposes. Approximately 70% of the potable water distributed in the Paarl area returns as waste water. This 12-18 ML/day of effluent is recycled up to a high quality, certified standard before being released into the Berg River for users downstream, 10ML/day of which is used by agriculture, watering of sports fields and the like.
Another Drakenstein waste water treatment plant in Wellington produces about 6-8 ML/day of recycled water.
To the east, Stellenbosch started its initiatives earlier and is well progressed with providing water via boreholes. The intention is to get Klapmuts, Dwarsriver, Meerlust and Franschhoek off the grid and thereby to reduce their draw on the Wemmershoek Dam. Stellenbosch itself is served by several rivers and has 6 boreholes currently producing 50L/sec, is developing another two to produce an extra 30L/sec with potentially a further 3 boreholes that can be added later. Its local storage point is the Idas Valley Dam which holds some 2.2 M.cuM (around four months supply; it is 97% full).
Stellenbosch has new or recently renovated water treatment plants. 3-4 ML/d is recycled back into the Eerste Rivier for use by farmers lower in the system. Initiatives are under way to reclaim more of the available 10 ML/d of effluent and to swap this with agricultural users for their equivalent potable water allocation. Cost estimates for the capex spend needed for such reclamation is R4million to produce 1 ML/d via micro-filtration vs R15million capex to produce 1 ML/d via reverse osmosis.
From discussing activities with the various responsible officers it appears that the municipalities are all in close contact with each other and also DWS in planning and agreeing allocations and use of available water. Everyone is striving hard to optimise the situation and reduce dependence upon the dams. All appear to be operating on level-6 restrictions and claim to have achieved a 40%+ reduction in consumption.