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Water quality of lakes and rivers of Upper Waitaki highlighted

An overview of the water quality of the lakes and rivers in the Upper Waitaki catchment has been presented to the Upper Waitaki Water Zone Committee.

The past year’s annual water quality monitoring results show that five lakes in the zone have not met the Trophic Level Index (TLI) set in the Canterbury Land and Water Regional Plan, although results in several lakes are likely to be impacted by heavy rainfall last summer.

In addition, a number of the rivers in the Upper Waitaki are showing signs of degrading in terms of aquatic life and water quality.

The results were presented by Principal Science Advisor Graeme Clarke, who says while the larger lakes are still in very good health, there have been water quality decreases in a number of rivers throughout the zone.

“In general, the large lakes in the Upper Waitaki such as Ōhau, Pūkaki and Tekapo/Takapō are still in very good health with low nutrient levels, but the results from the past year’s monitoring have shown a decrease in water quality compared to last year.”

“The change could be linked to heavy rainfall experienced in December 2019, which can wash nutrients and sediment from land into the waterways. It’s important to note that this monitoring is different to swimming and contact recreational water quality – which shows that all sites in the zone are suitable for swimming,” Clarke said.