30 October 2025

Several controlled areas will be created at Lake Hood for trials of treatment options for the mitigation of cyanobacteria blooms in the future.

Council is planning to create a controlled area in part of a canal along Huntingdon Avenue, to test five different applications, and other areas of the lake will be used to monitor three different types of sonic equipment. The data collection and monitoring will be led by a team from Lincoln University.

Group Manager of Infrastructure Neil McCann said a pre-test in November will provide good information and assist the more scientific trial in February or March, when cyanobacteria levels typically rise.

“We’ll be restricting access to the pre-test zone once it is established so people won’t be able to boat down that canal for about four weeks.”

He said residents and visitors to the lake will also see information signs going up near the lake as the weather warms up.

“These are designed to educate lake users about cyanobacteria, because we know water quality conditions in the lake change quickly in the warmer months.”

Environment Canterbury will begin its annual monitoring of swimming and water recreation sites on 17 November and will be taking weekly samples from Lake Hood – the results will be posted on the LAWA website.

Mr McCann said Council would also keep residents and the community informed via a dedicated Lake Hood page on its website, ashburtondc.govt.nz

“We’ll be continuing our regular water quality updates and sharing information about any other work through the summer.

“We’re also continuing to work with some volunteers from the lake community, who will help download data from the monitoring buoy and clean it, and also assist with using our hand-held cyanofluor device, which will give an indication of cyanobacteria volumes.”

Scientists will be back at the lake soon to finish a survey of the lake bed and canals, and this information will help create a 3D model of the lake, and model how water flows.

Mr McCann said gathering information and helping the scientists was part of the longer term water quality work.

“From an operational perspective in the shorter term, we are channelling water to improve circulation in the canals and we’ll have the weed harvester operating. We’ll also be keeping a close eye on cyanobacteria levels throughout the summer.

“Our aim is to mitigate those levels rising to the point where a health warning is issued.”

Council is now handling bookings and general inquiries for the lake, and these can be sent to lakehood@adc.govt.nz