Woahink Lake data show somewhat stable levels of phosphorus and algae-causing chlorophyll-a, and no health concerns.

Woahink and Siltcoos lakes are the primary drinking water sources for Dunes City, and for that reason, preserving the quality of the lakes remains a high priority for the city’s approximately 1,330 residents.

At the July 8 Dunes City Council meeting, Mark Chandler, volunteer project manager for the city’s water monitoring program, presented data examining three water quality parameters for the lakes: clarity, chlorophyll-a, and total phosphorus.

Volunteers trained by the Oregon Department of Environmental Quality collected the statistics, which were recorded over the last six years.

According to Chandler, the water clarity measurements were taken by lowering a standard disc into the lakes and recording the maximum visible depth.

At the Atlas site in Woahink Lake, the average depth currently is about 20 feet, greater than it was in 1990.

Data for Siltcoos Lake indicate less water clarity — five to six feet — in recent years, reflecting the 2007 and 2008 blue-green algal blooms.

Lower clarity readings correspond to either high rainfall and runoff or algal blooms, Chandler said.

Chlorophyll-a levels were tested in micrograms per liter at Woahink and Siltcoos lakes from 2004 to June 2010. During this time, water samples were sent frozen to the University of Washington to process.

For the complete article see the 07-28-2010 issue.

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