As winter settles on the hills around Lake Clearwater, Environment Canterbury’s (ECan) team has been installing new water monitoring equipment on the lake.
Over the past few months, its scientists have been collecting essential data sets from beneath the surface of Lake Clearwater. Four monitoring stations are providing detailed information that support work to improve the lake water quality.
ECan director of science Tim Davie said the four monitoring stations (mid-lake at Lakes Clearwater and Heron, and near the shore at Lakes Camp and Emma) were providing detailed information for a programme to improve lake health at Ashburton Lakes.
At Clearwater, a new central logger records data from the various sensors to capture the same information, including algal biomass (amounts of algae) and turbidity (water clarity) – but the visual appearance and the proficiency of the station would change.
It would consist of one central station which holds the monitoring equipment with a solar panel, several marker buoys, and four smaller buoys to mark the position of the anchor ropes.
Additional work was under way to investigate the lake’s nutrient sources, including using piezometers to examine groundwater. Staff would also work with local farmers on immediate voluntary actions they can take to reduce the risk of nutrient loss to waterways.
Alongside that, ECan was developing a lake-by-lake land use risk analysis, which would include the required nutrient reductions to improve lake water quality – while its partners were leading work to understand the changing environment through a matauranga lens.
Davie said, “We already have clear evidence that the water quality of these lakes is concerning, with high nutrient levels and algal growth.
“The focus of everything we are doing now, including this monitoring and on-the-ground work with landowners, is to improve water quality.”
The information is being collated and analysed by the science team to give a better understanding of each lake’s unique ecology and how nutrients, algae, and oxygen are interacting with each other.
Davie said the water monitoring was just a small part of a wider programme to directly address the health of the Ashburton Lakes.
“ECan, working with DOC and the Cawthron Institute, has conducted detailed work across the whole catchment to assess the changes needed to reduce nutrients to a healthy level,” he said.
“In addition, our land management advisory team has been working directly with farmers in the area on immediate voluntary actions they can take this summer to further reduce the risk of nutrient loss to waterways.”

• By Pat Deavoll