Clanwilliam Dam is a concrete gravity dam on the Olifants River, near Clanwilliam, Western Cape, South Africa. It was established in 1935, and the wall was raised to its current height of 43 metres (141 ft) in 1964. The main purpose of the dam is to provide irrigation water to the agricultural region downstream. It has a capacity of 121,800,000 cubic metres (4.30×109 cu ft). The feasibility of raising the dam wall by another 15 metres has been investigated.