Alarm at Ashburton Lakes water quality deterioration Increasing concentrations of nitrogen and other
Increasing concentrations of nitrogen and other contaminants in our lakes is causing concern for the Ashburton Water Zone Committee to the point where committee member Ben Curry warned that the reducing quality could “tip over to a point they are buggered”.
The results of a DOC restoration and conservation project in the Ashburton Lakes was presented to the Water Zone Committee in April.*
The summary of the results of water aquality monitoring data indicate trends, especially with
nitrogen increase, were a cause for concern at a number of sites, the Ashburton Courier reported on April 4 2019.
The report was presented by DOC principal freshwater scientist Hugh Robertson, of Nelson, and freshwater technical team member Tom Drinan, of Hamilton. It was an update on the state of the trend of water quality in the Ashburton Lakes district and the streams of the Maori Lakes catchment.
DOC sought action from the committee to help work with Environment Canterbury and landowners to reduce the loss of nitrogen and phosphorous sediment into streams in the outer vulnerable lakes, such as Maori, Heron, Camp and Clearwater.
Mr Robertson said there were studies that showed that water-bitd contaminant was limited and the majority was linked to landuse.
Risks to lake health included eutrofication (excessive richness in nutrients), water clarity,
hydrological change, less flow (to flush nutrients) and increased pest fish such as perch.
Mr Curry said: “There's a bit of an alarm bell ringing here.” The committee has sought information from Ecan on existing work being done with affected stakeholders.
A cloud of truck-spread superphosphate (top left) drifts over Lake Roundabout
on a southerly breeze from the turnip paddock (right) on July 23, 2019.
Fertiliser chips and dust rained onto the Lake Emma road
and across onto Lake Roundabout.
LCHHA Newsletter November 2019