Lake Waipu

Lake Waipu, just south of Rātana Pā,[1] is a 7 ha (17 acres) shallow coastal aeolian, or dune-dammed, lake. Horizons Regional Council has monitored water quality in the lake since 2015. The lake's catchment is mainly pasture and Rātana's treated sewage runs into a tributary of the lake, accounting for the trophic level index being eutrophic at 6.9, though the submerged plant indicator of 34.3% is better and kākahi (native freshwater mussels) live in the lake.

Lake Waipu
Aerial view of Lakes Waipu and Oraekomiko 2021-22
Lake Waipu
Location	North Island
Coordinates	40.045°S 175.158°E / -40.045; 175.158
Type	dune lake
Catchment area	527 ha (1,300 acres)
Basin countries	New Zealand
Max. length	700 m (2,300 ft)
Surface area	7 hectares (17 acres) (open water)
Max. depth	4.7 metres (15 ft)
Settlements	Rātana Pā

A $1.75 million project with the Ministry for the Environment, Rangitīkei District Council, Ngā Wairiki Ngāti Apa, Rātana Community Board, and the Department of Conservation,[2] will pipe the wastewater to land near Whangaehu beach. With planting and other improvements it is planned to improve the lake's pollution.[3]

Lake Waipu usually drains through the sand, as does nearby Lake Oraekomiko, though in places, especially in wet weather, a stream runs 2.2 km (1.4 mi) to the Turakina River.[4]