Onkaparinga River
| Onkaparinga River | |
|---|---|
 | |
| Physical characteristics | |
| Mouth | Port Noarlunga |
| Length | 95 km |
The Onkaparinga River runs from its source near Mount Torrens in the Mount Lofty Ranges, and flows south westerly to an estuary at Port Noarlunga. The catchment is over 500 km² in area, and is in part located in the Onkaparinga River National Park.
The Onkaparinga River is the second major river of the Adelaide region, after the River Torrens. The name derives from the indigenous Kaurna name Ngangiparri which translates as "The Women's River".
It is a source of fresh water for the city, Mount Bold Reservoir was constructed between 1932 and 1938 along a section of its path approximately 20km inland. Much of its flow diverted via a tunnel from the Clarendon Weir to the Happy Valley Reservoir, that in turn supplies some 40 per cent of Adelaide's water supply. Most years the flow to the reservoir is supplemented by water pumped from the River Murray via a pipeline from Mannum.
Downstream from Mount Bold Reservoir is the Clarendon Weir. To maintain levels at Clarendon Weir, water is released only as required. The Onkaparinga Gorge extends from Clarendon to Old Noarlunga. An estuary extends from Old Noarlunga to the river's mouth at Port Noarlunga. The estuary is a significant breeding area for local marine fish species.
