Quarterly Water Quality Report – November 2025
Opuha Water Ltd publishes its quarterly water quality reports for Lake Opuha and the wider scheme catchment to share with the community the results of our extensive water quality monitoring program.
The November water quality report summarises the key results and conclusions of Opuha Water: Kakahu River biomonitoring July 2025, an ecological survey of the Kakahu River in July 2025 carried out by Water Ways Consulting. The survey included macroinvertebrate, fish, periphyton and fine sediment monitoring.
Key points:
- Water Ways Consulting undertook a biomonitoring survey in the Kakahu River in July 2025.
- Streambed embeddedness was low. All sites achieved CLWRP outcomes and NPS-FM A band.
- Periphyton ranged from 45% to 76%, and all sites achieved the CLWRP outcome for filamentous algae.
- The macroinvertebrate community index (MCI) waterway ratings in the Kakahu River were GOOD (Mulvihill Bridge and Downstream of Discharge) to FAIR (all other sites).
- The quantitative macroinvertebrate community index (QMCI) waterway ratings in the Kakahu River were GOOD (Mulvihill Bridge, Upstream of Discharge and Downstream of Discharge), FAIR (Hanging Rock Rd Bridge) and POOR (Morrison’s Bridge).
- Longfin eel, upland bully, common bully and brown trout were caught in the Kakahu River.
- Results from this survey and previous surveys undertaken by Water Ways Consulting (August 2024 and December 2024) indicate that the macroinvertebrate community, and, in general, the health of the Kakahu River, is affected by catchment-scale processes occurring upstream and downstream of the discharge.
Download the full report here: Water Quality Report – Kakahu Biomonitoring Nov 2025