DAMS IN SOUTH AFRICA: Western Cape
W Cape E Cape N Cape Gauteng KZN Mpumalanga Free State Northwest Limpopo
Alexandra Dam Max. capacity 0,13 mil.cub.m. Disa River
Applethwaite Dam Max. capacity 3.3 mil.cub.m. Palmiet River
Arieskraal Dam Max. capacity 5.9 mil.cub.m. Palmiet River
Berg River Dam Max. capacity 126.4 mil.cub.m. Groot Berg River

Bellair Brakrivier tributary of the Gouritz.
Buffelsjag Dam
Bulshoek Dam  Olifants River
Clanwilliam Dam  Max. capacity 121.8 mil.cub.m. Olifants River
Draaivlei
Duiwenshok Dam Duiwenshok River
Floriskraal Dam Max. capacity 50.3 mil.cub.m. Buffelsrivier tributary of the Gouritz.
Gamkapoort Max. capacity 37.3 mil.cub.m. Gamka River tributary of the Gouritz.
Greater Brandvlei  Off-channel storage dam, filled by a canal from diversions out of the Smalblaar and Holsloot Rivers (tributaries of the Breede River). Ref 1.
Hartebeeskuil Dam
Hely-Hutchinson Dam Max. capacity 0.95 mil.cub.m. Disa River
Kammanassie Dam Max. capacity 34.8 mil.cub.m.
Keerom (Nuy) Max. capacity 10.4 mil.cub.m Nuy River/Breede River
Kirstenbosch Dam Liesbeeck River
Kogelberg Dam Max. capacity 19 mil.cub.m. Palmiet River
Koos Raubenheimer Grobbelaarsrivier tributary of the Gouritz.
Korinte-Vet Dam Max. capacity 8.1 mil.cub.m.. Korinte River
Kwaggaskloof Dam Breede River
Lakenvallei Dam Max. capacity 10.3 mil.cub.m. Sanddrifskloof River
Miertjieskloof Dam
Misverstand Dam  Max. capacity 6.4  mil.cub.m. Groot Berg River
Osplaas Dam Tributary of the Hex River/Breede River
Oukloof Sand River tributary of the Gouritz.
Pietersfontein
Poortjieskloof Dam
Prinsrivier Dam Prinsrivier tributary of the Gouritz.
Rockview Dam
Roode Elsberg Dam
Steenbras (Upper and lower) Max. capacity 31.0 and 33.9 mil.cub.m. Steenbras River
Stettynskloof Holsloot River/Breeder River
Stompdrift Max. capacity 49.6 mil.cub.m. Olifants River tributary of the Gouritz.
Theewaterskloof Max. capacity 434 million m3 Riviersonderend tributary of the Breede.
Victoria  Dam Max. capacity 0.13 million m3 Disa River
Voëlvlei Dam Max. capacity  158.6  mil.cub.m. The dam is supplied by diversion works from the Klein Berg, Vier-en-twintig and Leeu Rivers.
Wemmershoek Dam

Max. capacity 58.7  mil.cub.m.

Wemmershoek River tributary of the Groot Berg
Wolwedans Dam

Great Brak River
Woodhead Dam

Max. capacity 0.93  mil.cub.m.

Disa River

GoogleEarth view of dams in the Western Cape

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References: 
Ref 1:  Department of Water Affairs and Forestry, South Africa. 2004. Breede Water Management Area: Internal Strategic Perspective. Prepared by Ninham Shand (Pty) Ltd in association with Jakoet & Associates, Umvoto Africa and Tlou and Matji, on behalf of the Directorate: National Water Resource Planning. DWAF Report No P WMA18/000/00/0304.