The Riviersonderend is a stream system flowing through the Western Cape province of South Africa. The river and its associated catchment area, known as the Riviersonderend Complex, cover a significant expanse of approximately 28,580 hectares. The system includes a major impoundment, Theewaterskloof Dam, which is part of a large-scale inter-basin water transfer scheme, moving water from the Riviersonderend catchment to the Berg River system. The upper catchment areas, such as the Amandel and Du Toit rivers, are ecologically significant, hosting unique and endemic freshwater species. The river's course winds through varied landscapes, from mountainous headwaters to more open valleys, creating diverse aquatic habitats.