Port Elizabeth's earliest water supply came from the Shark River at Happy Valley and the Donkin Stream next to the Donkin Reserve. As the city started to grow in its early days of development the demand for water far exceeded this meager supply. After a competition held by the Port Elizabeth city council in 1862 to find proposals to supply the city with water, a weir and small dam was built in the Van Stadens River. This was later followed by the Bulk River (1903) and the Sand River (1907) dams in the Elands River Valley, both which can be seen driving along the Elands River Road. Of cause these dams have since been replaced as the main supply dams by the Kouga, Churchill and Mpofu dams. Both the Sand River and Bulk River are tributaries of the Elands River which in turn at its concourse with the Kwazunga River forms the Swartkops River.
When we visited the dam wall of the sand river was overflowing. 
Information supplied courtesy of the Port Elizabeth Daily Photo blog