Lake turns corner on toxic slime

Devils Lake water quality managers say they’re turning back the tide of blue-green algae, a toxic slime that has periodically closed the 685-acre lake to public use. Examining a batch of the cynotoxin bacteria was marine contractor and DLWID board member Bill Sexton. (Photos by Rick Beasley) A buildup of silt at the outlet of the D River has helped raise lake levels to alarming highs, causing private docks to float away and creating lakeside erosion.

LINCOLN CITY — Devils Lake water quality managers say they’ve turned the corner on toxic slime but are wrestling with unusual flooding and the effects of a fish-killing sea lion that unleashed an infestation of unwanted sea grasses

At stake in the battle against potentially deadly blue-green algae and invasive water weeds is a multi-million-dollar economy that rings the 685-acre lake, which serves as a magnet to anglers, boaters, campers and homeowners.

“Before the creation of the Devils Lake Water Improvement District (DLWID), the lake was over 80 percent vegetation and had lost almost all economic value at that point,” recalled Josh Brainerd, manager of the the agency since 2016.

While a 20-year effort to clean up the lake with grass-eating carp and cutting-edge aeration technology has turned back the tide of weeds that once choked the state-owned lake, Brainerd said unexpected problems continue to challenge the tiny, $1 million agency.

For example, a federally protected sea lion that made its way up the 120-foot-long D River last year wiped out the lake’s remaining grass carp, allowing the invasive weed “Parrot Feather” to gain a foothold. Brainerd reported to the DLWID Board of Directors last week that both chemical and mechanical methods will be used next spring to combat weeds threatening boat ramps.

“It’s like a set of dominos,” asserted Brainerd of the issues facing the 14,000-year-old lake. “One problem goes down, and another crops up. We’re just beginning to understand lakes and basins, as the science is just beginning to expand.”

He described the carp program as “overly successful,” saying they ate so much vegetation, the balance was tipped in favor of dangerous cynotoxins.

Aerators were installed with notable success in November, 2018, however, to deal with harmful algal blooms that periodically closed the lake to the public. Known as blue-green algae, the slimy substance develops from a combination of nutrients, sunlight and warm water temperatures.

“It’s doing an excellent job,” said Brainerd of the aeration equipment, some of it portable for placement in coves and along shorelines at the request of lakeside homeowners. “We’ve had great luck in targeted areas.”

Aeration of the lake bottom has resulted in widespread oxygenation of the lake, which averages 9 feet but is 21 feet at its lowest depth. The infusion of dissolved oxygen has created new fish habitat and beneficial plant growth while improving water quality, claimed Brainerd.

“We also witnessed a major decrease in blue-green algae concentrations,” he added.

An issue that has sparked widespread concern is the unusually high lake level, pushed to more than 11 feet by silt build-up at the D River outlet. Some canals have spilled over, and board chairman Tina French said her lakefront home gathered several floating docks in recent days.

“I have two more ‘floaters’ on my property,” remarked French at the Feb. 13 directors’ meeting. “For the record, I want the public to know we did not dam the lake. People are concerned their docks are under water or floating away, but it’s no doing of ours.”

Brainerd hopes to tackle flooding issues with a $12,000 dredging job, but that is awaiting a signature of approval from the Oregon Department of State Lands.

Another advanced technology to help the district may soon take off with the licensing of DLWID volunteer Weston Fritz to pilot a $6,000 drone the agency plans to buy. Fritz attended a free drone-pilot school in McMinnville and has passed a licensing test with the Federal Aviation Administration to fly the drone, which will be used to look for problem areas on the lake.

At their meeting, directors filled a vacancy on the five-member board. Mitchell Moore, the only applicant, replaced Kent Norris and will serve the remaining three years of the term. Other directors attending the Feb. 13 meeting included French, Steve Brown, Kathy Kreme and Bill Sexton.


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