High Quality Content by WIKIPEDIA articles! Lake Rotorua is the second largest lake in the North Island of New Zealand by surface area, and covers 79.8km2. With a mean depth of only 10 metres it is considerably smaller than nearby Lake Tarawera in terms of volume of water. It is located in the Bay of Plenty region. The city of Rotorua is sited on its southern shore, and the town of Ngongotaha is at the western edge of the lake.