The river flows generally eastwards for about 60 kilometres (37 mi) and passes through the steep Kawarau Gorge until it joins Lake Dunstan near Cromwell.

Before the construction of the Clyde High Dam, the Kawarau joined the Clutha River / Mata-Au in a spectacular confluence at Cromwell.

A natural bridge, Whatatorere, where the river narrows to 1.2 metres (3.9 ft), was important first to early Māori and then to goldminers as the only place the Mata-Au and the Kawarau could be crossed without boats.

[7] Fish and Game has sought an amendment to the Water Conservation Order to prevent any damming of the Nevis River and to seek conditions on changes to the minimum flows.

[1] In 1910, 57 years after the event, Nathanael Chalmers remembered his boat trip through the Cromwell Gorge: ‘I shall never forget the “race” through the gorge ... my heart was literally in my mouth, but those two old men seemed to care nothing for the current.’ [11] More recent tourist adventure activities on the river include riverboarding, jet boating, white water rafting, river surfing, and bungy jumping.

The Kawarau Gorge Suspension Bridge, 43 metres (141 ft) above the river, and a Category I historic place,[12] is the site of the world's first commercial bungy jumping operation.

The Kawarau is the largest volume river commercially rafted in New Zealand, with an average flow of 216 cubic metres per second (7,600 cu ft/s) at Chards Road measuring station.

[13] The four significant commercially used rapids on the river are Smiths Falls, Twin Bridges, Do Little Do Nothing and the 400-metre (1,300 ft) Chinese Dog Leg.