More flooding at Newman Lake is inevitable this spring, according to the Spokane County engineer.
“We’ve about run out of ways to deal with it (runoff), so my prediction is: There will be more flooding,” Bill Johns told county commissioners Tuesday.
County officials have called a meeting for 5:30 tonight at the Tri-Community Grange near Moab Junction to discuss Johns’ dire predictions with Newman Lake residents.
“We’ve got to make sure they know what’s coming,” said Commissioner Kate McCaslin.
Last month, water from the 1,200-acre lake overwhelmed its flood-control system, sending a torrent of water over roads and through a mobile home park about a mile from the lake.
Hard work by Newman Lake residents prevented serious damage. Many of the sandbags they filled are still in place.
The lake is contained behind permanent dikes and drains into a canal that leads to a pit, where the water is allowed to seep into the ground.
For nearly two weeks, the canal has carried more than twice the water it was intended to handle, Johns said.
The water is so silty that the pit is draining too slowly to keep up with the water coming into it. Attempts to dig out the silt have been unsuccessful.
Temporary ditches carry the excess water to a private pit. But even that desperate step wasn’t enough to prevent flooding.
Worse, there’s only a foot of freeboard left between the surface of the lake and the top of the dikes, Johns said. If the snow still left in the hills above Newman Lake all melted at once, it would overfill the 30-foot-deep lake by 10 feet, he said.
“This is our Mississippi River. You know it’s coming, but you can’t hold it back,” said Dennis Scott, public works director. “If we get a warm wind with rain, we’ve got a big, big problem.”
Historically, Newman Lake spread over fields to the south during spring runoff. Farmers diked the lake in the early 1900s and dug an irrigation canal so they could till the rich peat soil.
In the early 1970s, the U.S. Soil Conservation Service added floodgates, deepened the canal and dug the pit to contain the runoff.
This year’s floods have turned those fields into a haven for swans and other waterfowl.
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