Waipaoa River

Key subcatchments of the Waipaoa include the Waikohu, Mangatu, Waingaromia, Wharekopae, and Te Arai.

Some of the subcatchments are particularly susceptible to soil erosion, notably in the Waingaromia and Mangatu areas. As a result, the bed in the lower reaches of the catchment is building up due to sediment and gravel deposition. The Poverty Bay flats and the city are protected by the stopbanks of the Waipaoa River Flood Control Scheme but since their construction 60 years ago, flood capacity has been lost and the scheme is about to be upgraded again at substantial cost. Annual suspended sediment load for the Waipaoa catchment is 15 million tonnes or 33.54 cubic metres per second. This amount of sediment enters Poverty Bay.

Despite the high sediment loads of the lower reaches of the Waipaoa catchment many of the tributaries in the headwaters provide habitat for a range of indigenous fish species. These species rely on migration up the river system as juveniles and return to the sea as adults. Eels are one example in the fishery that requires this ability to migrate.

Trout are present in the Wharekopae tributary. They have been introduced and are not known to migrate.