Mangapu River

Story

The Mangapu River is a river of the Waikato Region of New Zealand's North Island. It has its sources in numerous streams which flow generally northwards from the King Country south of Te Kuiti, the longest of which is the Mangaokewa Stream. These streams join to form the Mangapu close to Te Kuiti, and from here the river flows north, passing close to the east of Waitomo Caves, where the Mangapu caves have the largest entrance in the North Island (about 100m long and 90m deep), before flowing into the Waipa River at Otorohanga.SH3 crosses the river on a 111m bridge near Otorohanga built in 1966 and near Hangatiki on a 41m concrete bridge built in 1977. The railway follows the east bank for about 6km, crossing only small tributaries, though it did suffer from flooding, for example in 1905.The river at Otorohanga is classed as being in the worst 25% of similar sites as regards all measured pollutants, though some attempts are being made at restoration.Pehitawa Kahikatea Forest ReserveThe reserve 18.5ha of kahikatea forest on the east bank of the river, was purchased by the Native Forests Restoration Trust in 2001. Kahikatea forest once covered 41000ha in the Waipa Ecological District, now reduced to 158ha, of which 52ha are in the Mangapu valley, though over 70ha has been felled since 1975. A major drainage scheme was carried out just upstream from the reserve in the 1930s, including emptying of a lake. The forest floods in winter and flood protection would be uneconomic. Some kahikatea in the reserve are about 120 years old. The reserve also has swamp maire, matai, titoki and pukatea. Te Araroa long distance walkway passes through the reserve and crosses the river on a suspension bridge.