Irrigation schemes that take water from the rivers are controversial for a many reasons.
But in a New Zealand first, the developer behind Canterbury's Rangitata water storage scheme has constructed a salmon-spawning race next to its ponds, to hopefully increase the number of fish in the river.
One by one the hatchery-raised salmon flop into the water. The race is to be their new home, but only for a few days. They'll spawn there straight away and then die.
The purpose-built, 500-metre-long spawning race is the first in the country.
The $1 million project was paid for and constructed by the developers of the Rangitata River irrigation scheme, and it sits right next to their storage ponds.
Steve Agnew, an engineer at Rooney Earthmoving, says the spawning race was helping to give back to the environment.
"We wanted to give back to the river and as part of the irrigation project we wanted to include a fish-spawning race in the project."
The gravels used in the race provide the perfect safe habitat for salmon to bury their eggs. When they hatch they'll return as adults to continue the breeding cycle.
Fish and Game officer Mark Webb is convinced the race will help see a rise in young salmon.
"We're looking at between 30 and 50 percent increase in the total number of juvenile salmon in the Rangitata River, because we will have lots of spawning here, which is additional to the wild spawning."
Keen angler Phil de Joux has set up a salmon hatchery to supply the egg-filled fish. They're juveniles now but as adults they'll spawn in the race.
"The salmon fishing on the Rangitata has been in decline over the past few years, and anything that can help and enhance the river is marvellous."
They only put 40 fish in the race this first season. But now they know it works, there'll soon be many more fish going in for salmon seasons to come.
source: newshub archive