Wainui River (Bay of Plenty) Wainui River (Bay of Plenty) The Wainui River is a river of the Bay of Plenty Region of New Zealand's North Island. It flows north from the Kaimai Range to reach Tauranga Harbour south of Katikati. The catchment has of stream margins. 41% of the catchment remains covered in native bush, but 48% is under pasture and suffers soil erosion. The river includes 3 waterfalls of up to , which have been kayaked. The long former East Coast Main Trunk railway bridge is designated as the limit of the Coastal Marine Area. Downstream, a 3-span bridge takes SH2 over the
Bay of Plenty Public Health. The Bay of Plenty region covers 12,200 km² of land and 9,500 km² of coastal marine area. It extends along the eastern coast of the North Island, from the base of the Coromandel Peninsula in the west to Cape Runaway in the east. The region extends 12 nautical miles from the mainland coastline, and also extends from the coastlines of several islands in the bay, notably Mayor Island/Tuhua, Motiti Island, Whale Island and the active volcano of Whakaari/White Island. It extends inland to the sparsely populated forest lands around Rotorua and Murupara. The geographical bay is defined by