Waitangitaona River

The Waitangitaona River was the name of a single river of the West Coast Region of New Zealand's South Island.

Following a March 1967 avulsion, when it became two rivers, in 2018 they were renamed Waitangitāhuna River, for what had separated into the northern river, and Waitakitāhuna-ki-te-Toka, for the southern river.[1]

Te Rūnanga o Makaawhio asked the New Zealand Geographic Board (NZGB) to alter the names, after the 1967 flood diverted the river to a new course across an alluvial fan. Most of the southern flow runs into Lake Wahapo, but some was redirected (though the northern river is no longer fed by the southern river) into Graham Creek, which flows into the northern Waitangitaona River at its confluence with Matainui Creek, and then into Tasman Sea.[2]

NZGB accepted the change because major stopbanks erected in the mid-1980s have reduced the possibility of another avulsion of the river back to its former course, there is significant recreational use, so that emergency services sometimes need to identify the discrete rivers and the change recognises the historical significance of each name.[2]

Waitakitāhuna-ki-te-Toka, the southern river, flows for about 21 km (13 mi) to Lake Wahapo,[2] initially west, including a 57 m (187 ft) waterfall, from its origins in the snowfields of the Tatare Range,[3] south of Whataroa. From Lake Wahapo the water runs through Trustpower's 3.1MW Wahapo power station, built in 1960,[4] to the Ōkārito River. SH6 is the only bridge over the river.[5]

Waitangitāhuna River (translates to sounding, or weeping water), the northern river, flows generally north, then westwards for approximately 28 km (17 mi) from its source at the confluence of Graham Creek and Matainui Creek (which flows through Whataroa) to its mouth at the Tasman Sea,[2] just north of Okarito Lagoon. The shorter Waitangiroto River follows a roughly parallel course to the lower Waitangitaona one kilometre to the south. The Whataroa River reaches the Tasman 2 km (1.2 mi) to the north of the Waitangitaona's mouth.[6]