The Ōhikanui River is a tributary of the Buller River in New Zealand's South Island. It flows north for 30 km (19 mi), joining the Buller 20 km (12 mi) from its outflow into the Tasman Sea.[1] It and its smaller neighbour the Ōhikaiti River are often called the Big Ohika River and Little Ohika River respectively. Another variation is Ohika-nui.[2] Ōhikanui River has been the official name since 21 June 2019.[3]
A surveyor named the tributaries to the west of the Ōhikanui River using Greek letters, as Alpha, Beta, Gamma, Delta and Eta Creeks. He also named Dumpling Creek after he returned to camp on a cold wet day and was given a dumpling stew.[5]
The Ōhikanui River is a tributary consisting of a bouldery river bed and clear swift water.[6] It flows through the paparoa wilderness area which is unaltered (with no tracks or huts), though Buckland Peak Hut is just outside the catchment.[7] The area is popular with trampers because of its natural environment,[8] with Brown trout[9] fishers,[6] who use the river about 140 times a year,[10] and with deer stalkers.[citation needed]
There were never any sawmills in the valley.[13] Forest covers the whole valley, with no grassy flats. Tall forest is replaced by stunted forest, merging to alpine scrub, at 800 m (2,600 ft) to 1,200 m (3,900 ft), depending on aspect, landform and cold air drainage. The valley has an average of over 2,540 mm (100 in) of rain, more than 200 wet days a year[12] and rainfall has been measured at over 5 cm (2.0 in) per hour.[14] In the 1970s red deer, goats and rats were scarce, possums in moderate numbers and stoats everywhere. The valley now has pest control as part of the Paparoa Range TB Management Area.[15]
A truss bridge over the Ōhikanui was finished in September 1879, though the approaches, which required rock-cutting, took until March 1880.[16] Its spans were 3 x 60 ft (18 m) and 1 x 18 ft (5.5 m). It was built to cope with floods rising to 39 ft (12 m),[17] but floods in 1925, 1967, 1970 and 1971 covered the bridge.[18][19] The bridge was raised[20] and rebuilt as a 272 ft (83 m) timber truss on concrete piers in 1927,[21][22] though in later years it could only take light traffic and had to be supplemented by a bailey bridge.[23]SH6 now crosses the river near its mouth[24] on a concrete bridge built in 1992.[25]