The Western Cape Province, which is in the South West corner of South Africa, falls predominantly within two water management areas (WMAs), the Breede-Gouritz and the Berg-Olifants.

By GreenCape

While South Africa is one of the most water stressed countries in the world with a medium to high baseline water stress (20% – 40% average annual withdrawal of available water supply), the majority of the Western Cape falls within the two highest water stress categories (40% – 80% and >80%).

Water supply system

The Western Cape Water Supply System (WCWSS) is a complex, interlinked system of dams, pipelines, and distribution networks that supplies water to the City of Cape Town (CCT), West Coast District Municipality (which supplies water to Swartland, Saldanha Bay, and Bergrivier local municipalities), Stellenbosch, Drakenstein, and Witzenberg local municipalities, and certain agricultural users.

Total water allocation for the system is 590 million m³ per year, which is allocated to various end users. Approximately two-thirds of the allocation is for urban use (including residential, commercial, and industrial use), and the remainder is allocated for agriculture, which is predominantly used in the summer months. Irrigation to support agriculture constitutes the main water use in these two WMAs, followed by urban water use.

<Insert Green Cape Figure 1 on page 31 of 104 of PDF> Overview of Western Cape Water Supply System allocations by type

Effective demand side management

By the end of the 2020 hydrological year (31October 2021), the WCWSS dam levels had recovered to approximately 101%. Water restrictions for the City of Cape Town (CCT) were lifted at the end of the 2020 hydrological year, and demand has remained well below 800 Mℓ/day since 2017.

The ongoing effective demand side management, and resultant lower water use, was a key enabler in the recovery of dam levels. At the end of October 2020, the CCT’s average water consumption was 30% less than its allocation of 358 million m³ per year (981 MℓD) from the WCWSS. This highlights the importance and effectiveness of water conservation and water demand management (WCWDM), and water efficiency interventions, and the key role it has in managing the use of water resources.

However, non-revenue water (NRW) for Nonrevenue for some municipalities in the WC remains high at above the global best practice level (15%).

<insert GreenCape Figure 2 on page 32 of 104 of PDF> Non-revenue water levels for Western Cape municipalities for 2020 (Source: DWS Dashboard, 2020)

Municipality	Non-Revenue %	Water Tariff (R/Kℓ)	Potential loss in revenue (R/kℓ)
Beaufort West	48	R19.89	R9.55
Bergriver	10	R8.78	R0.88
Bitou	25	R12.87	R3.22
Breede Valley	22	R12.80	R2.82
Cape Agulhas	18	R9.92	R1.79
Drakenstein	11	R7.11	R0.78
George	4	R17.67	R0.71
Knysna	43	R7.84	R3.37
Langeberg	14.5	R3.07	R0.45
Matzikama	23.4	R8.21	R1.92
Overstand	26	R7.00	R1.82
Saldanha Bay	3	R11.59	R0.35
Stellenbosch	21	R20.82	R4.37
Swartland	12	R24.84	R2.98
Swellendam	36	R11.35	R4.09
Theewaterskloof	16	R11.00	R1.76
Witzenberg	35	R17.91	R6.27

Lower than average rainfall necessitates ongoing demand-side reduction to avoid dam levels approaching the critical levels.

The climate projections for the Western Cape indicate a warming trend as well as drying in many areas, with longer periods between increasingly intense rainfall events. Additionally, population and economic growth is placing an additional burden on water supply and sanitation systems, which in turn will have a negative impact on the province and consequently the country’s economy.

Augmentation schemes

In order to address future water constraints, various augmentation schemes have been introduced or planned. Augmentation schemes include potable water reuse (from WWTWs), groundwater development (new resources and artificial recharge), and large-scale permanent seawater desalination.

To date, the CCT augments its surface water with  7 Mℓ per day from groundwater and springs. This is likely to rise by 40 Mℓ per day from the recently commissioned Table Mountain Group (TMG) aquifer when it is fully operational. Other phased augmentation schemes will contribute a total of 240 Mℓ per day by 2026.

Intervention	First Water	Capacity (MℓD)	Total CAPEX (R million)	Unit CAPEX (R million)	Operating Cost (R/kℓ)
Table Mountain Group Aquifer – Steenbras	July 2020	25	468	18.7	5.5
Table Mountain Group Aquifer – Nuweberg	July 2023	15	523	34.9	5.5
Table Mountain Group Aquifer – Groenlandberg	November 2023	12	376	31.3	2.2
Cape Flats Aquifer – Strandfontein	July 2021	5	378	75.6	6.5
Cape Flats Aquifer – Hannover Park	May 2022	4	158	39.4	8.5
Cape Flats Aquifer – Strandfontein North and East	December 2022	15	772	51.5	6.5
Cape Flats Aquifer- Phillippi	December 2024	6	434	72.3	8.5
Cape Flats Aquifer – Mitchells Plain	July 2025	20	673	33.7	8.5
Atlantis Aquifer Rehabilitation and Expansion	July 2022	16	314	19.6	8.5
Berg Voëlvlei River Augmentation Scheme	July 2023	40			4.62
Water Reuse – Faure New Water Scheme	July 2025	70	1882	26.9	5.7
Desalination	December 2026	50	1880	33 – 40	9.0
Alien Vegetation Clearance			372