Blue Lake, Oregon

Blue Lake is a small lake located on the Columbia River floodplain, east of Portland. Blue Lake has experienced water quality problems for decades and efforts to control the water quality and plant-related problems
have included large, repeated doses of copper sulfate and lake level manipulations.

In 2003, the lake experienced a significant bloom of Anabaena flos-aquae and DEQ is in the process of preparing a TMDL for Blue Lake. To assist in this effort, MaxDepth Aquatics collected sediment cores from Blue Lake and analyzed the sediments for indications of changes in water quality. The results showed an increase in sediment accumulation rates, a change in diatom community composition and an increase in the composition of cyanobacterial akinetes.

Copper sulfate historically was used to treat the algae blooms, and the concentrations of copper in the sediment are gradually declining. DEQ is expected to use this information in setting target goals for lake restoration.