A lake in the South Island in New Zealand that's not far from Twizel?

There are numerous lakes in the Waikato region of New Zealand. The largest lake in the Waikato, as well as New Zealand, is Lake Taupo. Regions in New Zealand are based of river catchments, and as Lake Taupo is drained by the Waikato River, it is part of Waikato. Other lakes include Lake Rotoroa in central Hamilton and eight artificial lakes on the Waikato River, including Lake Karapiro, the host of the 2010 Rowing World Championships. These are just some of the lakes; there are plenty more around the region.