Lake Onslow

Lake Onslow is a man-made lake east of Roxburgh and south of Alexandra in the Otago region of New Zealand. It lies 700 m (2,300 ft) above sea level. It was formed in 1890 by the damming of the Teviot River and Dismal Swamp.

Lake Onslow
Lake Onslow In May 2014
Lake Onslow
Location	Otago, South Island
Coordinates	45°33′S 169°37′E
Type	reservoir
Primary inflows	Teviot River
Primary outflows	Teviot River
Basin countries	New Zealand
Surface elevation	700 m (2,300 ft)

The lake is the subject of several paintings by the late Edward Mullor.

In 2019, the Climate Change Commission proposed that the lake be used for a pumped hydro-storage system to provide backup electricity generation in dry years. The project had first been proposed in 2005 by hydrologist Earl Bardsley of the University of Waikato.[1][2] In July 2020, Minister of Energy Megan Woods announced that the New Zealand government would fund a detailed feasibility study of the plan.[3] If progressed, the scheme would be the biggest infrastructure project in New Zealand since the 1980s, employ an estimated 3500 to 4500 people, and take four to five years to build and a further two years to fill.[4] One option could be 5 TWh of storage and a 1.2 GW power station, equivalent to half a year of full production.[5]