Most improved river

Ōtukaikino River in Canterbury took out the supreme award for most improved river at the New Zealand River Awards 2018 late last year.

The river originates as a spring-fed stream on the Isaac Conservation and Wildlife Trust property, west of Christchurch. The stream supplies commercial salmon farming water races, flows through the Isaac Quarry and the trust’s captive bird breeding aviaries, and across the Isaac sheep farm before continuing downstream into neighbouring properties.

The river is part of a greater restoration programme being undertaken by Christchurch City Council which involves the staged removal of willows and scrubby weeds, followed by more than 195,000 eco-sourced native plantings.

The Isaac section of the Ōtukaikino is fenced off from prohibited stock, with a generous corridor of land provided to maximise the riparian planting zone along the waterways edge. Walkways have been formed along a significant stretch of river, extending between the 
Isaac Loop Track, Lake Roto Kohatu, Clearwater Golf Resort and the Waimakariri Recreational Reserve via the Isaac Farm Track.

The riparian plantings are all endemic to Canterbury. The land has been cleared manually, using brush cutters, machetes and axes with the slash left in piles as shelter from the Canterbury winds. This also provides a habitat for wildlife including invertebrates, increasing the biodiversity of the site.

Combi guards are used to mitigate against hares. Mulch is used when available, with some irrigation during summer. Initially maintenance spraying continues until a native canopy is formed. Ground preparation is minimal, with no fertiliser applied, so the natives must sustain themselves in the toughest environment from the outset.

The Ōtukaikino waterway demonstrates that a collaborative effort (from multiple landowners and organisations) can achieve significant ecosystem restoration, for the benefit of all.