O'Shannassy Reservoir
| O'Shannassy Dam | |
|---|---|
Location of the O'Shannassy Reservoir in Victoria | |
| Country | Australia |
| Location | McMahons Creek, Victoria |
| Coordinates | 37°40′30″S 145°48′20″E / 37.67500°S 145.80556°E |
| Purpose | Water supply |
| Status | Operational |
| Construction began | 1922 |
| Opening date | 1928 |
| Operator(s) | Melbourne Water |
| Dam and spillways | |
| Type of dam | Embankment with an internal reinforced concrete wall |
| Impounds | O'Shannassy River |
| Height | 34 m (112 ft) |
| Length | 226 m (741 ft) |
| Dam volume | 245,000 m3 (8.7 million cu ft) |
| Spillways | 1 |
| Spillway type | Uncontrolled |
| Spillway capacity | 500 cubic metres per second (18,000 cu ft/s) |
| Reservoir | |
| Creates | O'Shannassy Reservoir |
| Total capacity | 3.123 GL (687 million imp gal; 825 million US gal) |
| Catchment area | 11.9 ha (29 acres) |
| Surface area | 27 ha (67 acres) |
The O'Shannassy Reservoir is an Australian man-made water supply dammed reservoir. The 3.123 GL (687 million imp gal; 825 million US gal) water store across the O'Shannassy River is located near the locality of McMahons Creek, approximately 80 kilometres (50 mi) east of Melbourne, Victoria. The dam that creates the impoundment is called the O'Shannassy Dam.