Lake Rotongaro is located near Ohaki between the Waikato River and the larger Lake Whangape. It is a large shallow riverine lake, which links to the Waikato River.
The lake has a single outflow draining into Lake Rotongaroiti, which then flows through the Rotongaro canal, and on into the Lake Whangape outlet (via a floodgate structure) before it reaches the Waikato River.
The lake area is approximately 292 ha, with a max depth of 3.3 m. The catchment area is predominantly pastoral, with an estimated area of 1950 ha (www.en.wikipedia.org).
