Theewaterskloof dam spillway with water cascading over, flooding control

theewaterskloof dam spillway western cape floods flooding flooding control water level cascading overflow channel capacity water scarcity dam wall level controlled release villiersdorp reservoir western cape earth fill dam earthfill infrastructure sonderend river manmade dam water supply waterbody static no people cape town water supply south africa drought resistance weather rainfall concrete fresh overflow energy engineering flow architecture construction hydro outdoor barrier resource drain sluice rushing consumption structure downstream