ECan under pressure to address Kaiapoi River issues

Waimakariri’s deputy mayor has called on Environment Canterbury to stop "side-stepping" issues with the Kaiapoi River.

Waimakariri district councillor Neville Atkinson says ECan needs to step up and investigate the causes of pollution levels in the Kaiapoi and Ruataniwha Cam rivers.

Atkinson was addressing community concerns at a Kaiapoi-Tuahiwi Community Board meeting on Monday night.

Local residents formed a new catchment group last month, following concerns about the degradation on their local rivers which they blamed on the use of herbicides.

ECan has acknowledged issues with macrophyte (weed bed) dieback and freshwater mussel (kākāhi) deaths, but said it was primarily due to saltwater incursions and also heavy frosts.

But Cr Atkinson rejected ECan’s explanation.

"As is evident, this has been going on for years. It is very evident there is a problem and whether it is a natural problem or a man-made problem, I don’t know.

"But I want to know what it is.

"We owe it to our community to help ECan to come up with some answers, but ECan needs to stop side-stepping."

Cr Atkinson said residents may not like the outcome, but it was important to get some answers.

Councillor Philip Redmond said the issue was complex.

"If there was a simple fix, it would have been fixed a long time ago. It is going to be a long process."

Waimakariri District Council water environment advisor Sophie Allen said saltwater could come from other sources, but it was most likely from the sea.

Community members raised similar concerns following the 2010 and 2011 earthquakes.

A 2018 report by ECan principal scientist Adrian Meredith concluded there were multiple causes, but found ‘‘increasing episodes of saline water intrusion flowing into the lower Kaiapoi River’’.

The river was historically the north branch of the Waimakariri River and environmental changes following the earthquakes both contributed to the high levels of saltwater intrusion.

Drought conditions and changing farming practices were also factors, the 2018 report found.

The community board asked council staff to assist ECan to investigate the causes of saltwater incursions, including tides, river flows and salinity data and to monitor water quality and aquatic ecology trends.

Kaiapoi is known as the river town, with the river being a popular spot for boaties and whitebaiters.

By David Hill, Local Democracy Reporter

■ LDR is local body journalism co-funded by RNZ and NZ On Air.