Moses Lake as clean and clear as it’s been in 40 years, and that may be a reason for concern

MOSES LAKE – Ron Sawyer said the water in Moses Lake is as clear and clean as he’s seen it in the 40 years he’s owned and operated Cascade Marina.

“Until about two or three days ago, we could see the bottom,” the boating supply shop owner said of the clarity of the water in Moses Lake. “And we can look out and see the fish swimming around 18 feet off the dock.”

“We’ve never seen that since we’ve been here,” he added, of the Scott Road NE location.

The Bureau of Reclamation – which flows water through Moses Lake into Potholes Reservoir and then through canals to farmers and irrigators farther south – has sent 122,000 acre-feet of Columbia River water through Moses Lake since the irrigation season began in March, according to Chris Overland, executive director of the Moses Lake Irrigation and Rehabilitation District.

“That’s nearly the total volume of the lake put through it in the last two months,” said Bill Bailey, president of the MLIRD board of directors.

And it’s nearly 50,000 acre-feet more than the 77,000 the bureau sent through Moses Lake by this time in 2020, Overland told board members at a regular MLIRD meeting on Tuesday.

Overland told board members the MLIRD has received a number of positive comments about the quality of the lake water.

“People say they’ve never seen it so good,” he said.

However, Overland said he has no idea why the Bureau of Reclamation was flowing more water through Moses Lake.

The Bureau of Reclamation’s Ephrata office, which oversees the Columbia Basin Project, did not immediately respond to inquiries on the water flow through Moses Lake.

The Columbia Basin Project draws Columbia River water at Coulee Dam and delivers it through a series of canals, pipes and reservoirs to over 670,000 acres across the region and as far south as the Tri-Cities.

Sawyer said there was a lack of plant life and diversity of fish species in the lake right now, and wonders if the MLIRD in its previous aquatic weed treatments didn’t overdo it a bit.

“Normally, we’d have curly leaf pondweed growing like crazy out here. Even without spraying, there is zero,” he said. “And there are one or two smallmouth bass that spawned successfully, so we’ve got quite a few small fry swimming around, but I’ve not seen any other fish in here.”

Aside from some clumps of filamentous algae on the bottom of the lake, Sawyer said there’s nothing green in the lake right now. Despite the concern over blue-green algae, the lake needs a balance of plants and animals to thrive.

“You don’t have a healthy ecosystem without plants,” he said.

The MLIRD has received approval from the Washington Department of Fish and Wildlife and the Department of Ecology to begin aquatic weed treatments the first week of July. The treatments, which normally begin in June, were delayed this year after some confusion over state regulations on when the district could spray.

Sawyer, who ran for the MLIRD board in 2019 and is currently a member of the Moses Lake Watershed Council, which was established to address the lake’s late-summer blue-green algae blooms, said he hopes the MLIRD will rethink its weed treatment program because the lake needs more emergent vegetation.

“The MLIRD will have to back off on the spraying program and let that happen,” he said.