Drought raises water temperatures to unhealthy levels

By: 
AP
Staff Writer

COEUR D'ALENE (AP) — The drought is bringing warmer temperatures to northern Idaho lakes, stressing fish and threatening oxygen levels.
Lake Coeur d'Alene and similar large lakes are seeing temperatures in the 70s while smaller bodies of water, like Lake Cocolalla, are in the 80s, the Spokesman-Review reported.
"We're seeing water temperatures that are more typical for August," said Meghan Lunney, an aquatic resource specialist for Avista Corp.
Hot water means more plant growth and less oxygen, with the level completely depleted along the floor of Lake Coeur d'Alene's south end.
The absence of oxygen, called anoxia, showed up earlier than ever this year and affects how sediment behaves in the lake, Coeur d'Alene Tribe lake management plan coordinator Laura Laumatia said. The conditions can cause lake sediments containing toxic mining waste from the last century to become re-suspended in the water, she said.
"We're looking at four straight months of anoxia," Laumatia said. "It will be an interesting year for lake science, for sure."
Another problem, she said, is that aquatic weeds are flourishing, including invasive milfoil that's several weeks ahead of schedule. "It's pretty nasty - it looks like a big, brown mat over the lake," Laumatia said.
Health advisories are in place for Fernan and Avondale lakes and part of Hayden Lake. People are urged to avoid areas with blue-green algae blooms. Breathing problems and liver damage can result if the toxins produced by the algae blooms are ingested.
Lake Coeur d'Alene and Long Lake have each had isolated fish kills of perch and bullheads this year.
"If you rapidly warm the water, that can create extra stress that can be fatal," said Thomas Herron, Idaho Department of Environmental Quality's regional water quality manager.

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