Lake Water Suspected of Sullying Tualatin River
By Yuxing Zheng, The Oregonian, Portland, Ore.
Aug. 2–Water from Wapato Lake near Gaston has led to a fish kill and suspicions that it caused last month’s toxic blue-green algae bloom in the Tualatin River, and a musty odor and taste in some of Washington County’s drinking water.
Initial samples collected by the state Department of Environmental Quality on Friday near Wapato Lake indicated “pretty good water quality,” but results next week will determine whether action will be taken, said Avis Newell, the Tualatin basin coordinator for the department.
“There are times the oxygen in the water is very low, so they’re adding water of poor quality into the river,” Newell said.
The safety and quality of drinking water from the Tualatin River are not threatened, said Kevin Hanway, general manager of the Joint Water Commission, which provides water to 350,000 customers in Forest Grove, Hillsboro, Beaverton, Tigard and the Tualatin Valley Water District.
Low levels of dissolved oxygen in the lake water have contributed to the deaths of about 300 to 400 non-native carp, bluegill and catfish, said Todd Alsbury, a fish biologist with the state Department of Fish and Wildlife who visited the lake Thursday. Fish kills naturally occur, he said, and the Wapato Lake incident is not of tremendous concern in part because no threatened salmon, steelhead or trout were among the dead fish.
Meanwhile, Tualatin Riverkeepers blame the lake water for carrying nutrient-rich fertilizer runoff, spurring the toxic bloom that laced the river with aqua-colored mats of algae from Oregon 99W to West Linn.
The Joint Water Commission, the largest water supplier in Washington County, suspects the lake is the source of an earthy-tasting compound that costs an extra $6,000 a day to filter.
The Wapato Lake Improvement District manages the lake and is composed of the dozen or so landowners and farmers within the district.
Richard Adamson, a member of the district’s board, said the district would shut the water off “if they can absolutely prove this water is causing” the algae bloom.
Adamson also said he was not aware of any fish kill and that he has not seen any dead fish.
The 750-acre Wapato Lake is normally filled only during the winter, then pumped into the Tualatin River starting in February so that farming can begin on the lakebed in April.
The trouble began when last December’s fierce storm waters breached a dike and deluged the area. That delayed this year’s pumping of the water until about a month ago, and farming began on portions of the lakebed in late July. Most of the lake has since been drained.
Others contend that this year’s delayed pumping has already caused unintended consequences.
“The discharge is obviously causing serious problems for people downstream,” said Brian Wegener, the watershed watch coordinator for Tualatin Riverkeepers. “Oregon’s two enforcement agencies, Oregon Department of Agriculture and the Department of Environmental Quality, have been sitting on their hands while this discharge feeds toxic algae blooms, kills fish and makes thousands of people drink foul-smelling, nasty-tasting water.”
The Joint Water Commission noticed a musty scent and taste to its water starting in June and most pronounced in early July.
Workers from the commission took samples of the water at several points in the river and found higher levels of the compound geosmin, which causes the earthy taste and odor, downstream from the Wapato Lake discharge, said Hanway, of the commission.
The commission’s intake facility is about six miles downstream from the Wapato discharge.
The plant has filtered the compound since mid-June and water quality levels have returned to nearly normal levels, Hanway said.
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