Water boss happy with dam release

20:35, Mar 02 2014

Opuha Water's boss says he is happy with the results of the week's major flush flow from the Opuha Dam, but feels more could be done to clean up the Opihi lagoon.

Nearly 40 cubic metres a second were released from the dam on Thursday morning in an attempt to clean the Opuha and Opihi rivers of didymo and toxic algae.

Opuha Water chief executive Tony McCormick said compared with last year's major release, the results were a lot more satisfying.

"We were able to keep the water at a higher level for much longer. It stayed around 30 cumecs for several hours. When we attempted this last year, it died off pretty quickly," he said.

The flow remained as high as 14 cumecs until yesterday morning.

"We had a bit of luck with the tide too, in that it was low by the time the release reached the Opihi lagoon, so it had a more appreciable effect."


Some anglers expressed concern that the release would have no effect on the lagoon, and would in fact lead to further mess "being dumped at the bottom of the system".

Mr McCormick acknowledged those concerns, but said the early observations suggested it had been effective this time around.

"We rely on anglers to be our eyes and ears on the ground, so any feedback we get is appreciated," he said.

Central South Island Fish and Game chief executive Jay Graybill said the decision to open the river mouth helped with the release.

"Rather than the debris spreading out in the lagoon, it washed out to sea. It also provided sufficient flow to bring the salmon upstream. We're hopeful it had the desired effect of removing the toxic algae from the river," he said.

In the past few summers, there have been health warnings near parts of the Opihi and Opuha Rivers due to outbreaks of toxic algae. Currently, both are declared safe for swimming.

The Timaru Herald