A review of the health of two South Canterbury rivers – Opuha and Kakahu (Te Kākaho) – will be discussed at a community meeting in Pleasant Point next month (13 June), with scientists on hand to go through the key findings.

We commissioned the report, carried out by the Cawthron Institute, to provide an independent review of the ecological health of the Opuha and Kakahu Rivers.

The report provides information on the current state of the waterways, as well as identifying suggestions for further work to help inform how the health of these waterways could be improved.

Chief Scientist Dr Fiona Shanhun said the report will inform future actions to help us better understand the drivers of environmental health in the catchment.

”Along with the community, we’ve been concerned about the health of the waterways in this catchment. That’s why we commissioned an independent review of all the information available. The report identifies some recommendations for further work, and we look forward to talking to the local community and collectively considering next steps.”

Key findings

The report provides insights into drivers of river health as well as opportunities for further work that could help inform next steps.

The report’s key findings are:

• The ecological health of the Opuha River below the Opuha Dam has declined over time and is currently assessed as poor.
• The ecological health of the Kakahu River in the vicinity of the Kakahu Irrigation Scheme discharge is assessed as ‘moderate,’ but declines to ‘poor’ further downstream.
• Key drivers of the health of the Opuha River are the regulated flow regime and persistence of the invasive algae didymo.
• The key ecological driver of concern for the Kakahu River in the vicinity of the Kakahu Irrigation Scheme discharge is fine sediment arising from the discharge, with the increased variability and volume of flow also likely to play a major role.
• Knowledge gaps identified include the state of the Opuha trout fishery, drivers of turbidity in Lake Opuha, sources of fine sediment in the Kakahu River and the effects of changes in water flow.
• Claims of extreme DDT contamination have been extensively investigated and no work to date has substantiated these claims.

 Download the ‘Review of the ecological health of the Opuha and Kakahu Rivers (PDF file, 4.26MB)‘ report.

Community information session

Come to our information session and hear from both the scientists who undertook the review and our representatives on the ecological health of the Opuha and Kakahu Rivers. Bring along any questions you have for the team.

• Where: Pleasant Point Town Hall, Halstead Road
• When: Thursday 13 June, 4pm