The Māori name for Virginia Lake is Rotokawau, after the black shag birds that inhabit the lake area. Pākehā noted that the lake was similar to Virginia Water Lake in England, hence they named it Virginia Lake. Since March 2016 it has been officially known in the Whanganui district as Rotokawau / Virginia Lake.
Another less than peaceful story we heard from kōrero tuko iho about the lake's origins was that the lake came into being when local people asked of a tohunga how to rid themselves of a dangerous but well connected individual. Uppermost in people's minds was the need to avoid shedding blood on the land and creating a tapu, so a lake was created and death by drowning was the result for this unfortunate individual.
Geographically speaking, the lake is an example of a dune lake. These lakes are found along the west coast of the North Island and are formed when a stream is dammed by wind blown sand or when an existing dune depression is filled with clay and silt or sits on hard pan, which then reduces sub-surface water drainage forming a lake. The lack of a direct inflow of water into the lake makes the latter the more likely origin for Rotokawau / Virginia Lake. Rotomokoia/ Westmere Lake is another nearby example of a dune lake and both lakes have been important features of the city's water supply, past and present.
After Virginia Lake was purchased for the town in 1884, plans were put in place to make the lake look more attractive. Scrub and ferns were removed and the area extensively replanted. The reserve opened to the public in 1914.
Land was not developed for housing on the eastern section of the lake until the 1950's and the Otamatea sub-division to the north west was not developed until 2000-10. The area surrounding the lake therefore, would most probably have been linked to the agricultural land to the north of the city up until most recent times.
Rotokawau/ Virginia Lake is an iconic visitor attraction to Whanganui but it has been plagued by toxic and non-toxic algal blooms during summer for the last two decades.
Our interest in the lake grew out of Year 10 studies into the environmental impact of farming. We were interested in what happens when nutrients from fertilisers and manure end up in our rivers and lakes. The task now for the 10STEM students is to understand how Rotokawau/ Virginia Lake is impacted in a similar way and to investigate the processes that lead to algal blooms.