New proposal to tackle Western Cape, Southern Africa’s water woes

13th December 2019 By: Schalk Burger - Creamer Media Senior Deputy Editor

New proposal to tackle Western Cape, Southern Africa’s  water woes

KONSTANT BRUINETTE Gravity-flow water delivery systems are reliable, cost-effective and can deliver large quantities of water to areas a long way from the source

A large-scale water infrastructure development plan has been proposed by engineering consortium Trans Africa Water Alliance (TAWA) to meet the water needs of the Western Cape over five years, as well as Southern Africa up to 2100.

The plan was developed over the past three years by Dr Konstant Bruinette, who was chairperson of the BKS Acres consulting team of the Lesotho Highlands Water Project (LHWP). The LHWP uses gravity to transfer water from Lesotho to Gauteng and supplies more than 60% of the province’s water.

“The TAWA plan is similar to the LHWP and is an economically sound and practical solution to the problem of water supply to Cape Town and other areas in Southern Africa,” says Bruinette.

The first and most urgent phase of the plan will involve building a gravity-driven water-delivery pipeline from a new dam at Vioolsdrif, on the Orange river, to the existing Voëlvlei dam of the Cape Town metro water system so that the Western Cape no longer has to rely only on rainfall and be at the mercy of intermittent, catastrophic droughts.

The cost of the Cape Town metro pipeline would vary from $2.5-billion to $4.5-billion, depending on whether the Cape Town water supply increases by 15% or up to 50%. This equates to a cost below $1/m3 of raw water, and has been estimated to be between 10% and 25% of the cost of seawater desalination.

TAWA used the Development Bank of Southern Africa’s funding model, which has a repayment period of 14 years, as the formula to determine the costs, including the end-consumer costs, says Bruinette.

The Cape Town phase of the project can be delivered over four years, from start to completion, with an estimated additional year to secure funding and approvals, and will provide a secure supply.

Six-billion cubic metres of water a year is available from the Orange river. Large dams on the Orange river to impound major floods, which occur on average at 11-year intervals, can reliably meet the water needs of the Cape and Namibia.

“The Orange river has one of the largest catchment areas of any river in the world, at about one-million square kilometres. “The proposal is to build three dams on the lower Orange river. The first will be the Vioolsdrif dam, which will be built in phases to 9.6-billion cubic metres. The second, which will impound 46-billion cubic metres, will be built at Onseepkans, while the third, 1.6-billion-cubic-metre dam will be built at Boegoeberg.”

Plans and cost estimates for four other smaller lines have been prepared and proposed to the various water authorities.

These lines will run from the Van Der Kloof dam, delivering water to Port Elizabeth and then to Cape Town; from Boegoeberg to Cape Town; from Colenso to Albert Falls and then to Durban, in KwaZulu-Natal; and from western Lesotho to the Modder river supplying Bloemfontein.

Southern African Water

Other major pipeline projects have also been proposed that would integrate with various existing water infrastructure.

The second proposed line would be from the new Vioolsdrif dam to Swakopmund, in Namibia, supplying all the coastal towns in Namibia and pumping water from this line to the inland Namibian towns, including Windhoek. The third gravity line is from the Kunene river down to the Swakop river to supply Windhoek.

The fourth proposed pipeline would be from the Zambezi river to supply the 500-million cubic metres allocated by the Zambezi River Authority to the Dikgatlhong dam, in eastern Botswana, and extend this pipeline to the Mokolo dam, in South Africa. New lines from the Zambezi river would carry the water to dams in Botswana and South Africa from where Gauteng can be supplied.

“This would require a new water sale agreement from Zambia to South Africa, and up to six-billion cubic metres can be supplied to Gauteng, which should be a permanent solution to Gauteng water demand.

“The LHWP has for more than 30 years shown that gravity-driven water supply is a practical and economic solution to the problem. These gravity lines will solve the bulk of the water problems in Southern Africa,” he explains.

“Water authorities’ main constraining factor is the funding required for these projects. We are actively engaging with potential funders in South Africa, Europe, the US and the United Arab Emirates. However, we need government, local authorities and the general public to support this project,” he concludes.