The Boise River – already past flood stage in heavily populated southwest Idaho – will be raised again, federal officials said Thursday.
The U.S. Bureau of Reclamation and U.S. Army Corps of Engineers announced the river will go up to 8,500 cubic feet per second by Wednesday.
Flood stage is 7,000 cubic feet per second at the spot where the river exits Boise. It’s been flowing at about 8,000 cubic feet per second for several weeks.
“If we have an unanticipated warm-weather system come through that melts everything really fast, we have to make room to catch that,” said Army Corps of Engineers spokeswoman Gina Baltrusch.
Officials say the three dams above the state’s capital city have about 33 percent of storage space remaining, or about 315,000 acre feet. An acre foot is the amount of water it takes to cover an acre with a foot of water.
The snowpack in the 2,680-square-mile watershed is currently estimated at 2 million acre feet of water, meaning there’s about six times more water in the mountains than space available in the reservoirs to hold it.
The two upper reservoirs managed by the Bureau of Reclamation are used primarily for irrigation. The lowest reservoir is managed by the Army Corps of Engineers.
Managers operate them as a system, trying to make sure farmers have water for crops through the growing season while trying to avoid flooding cities downstream.
“This is a very delicately balanced system,” Baltrusch said.
Meanwhile, residents along the river have been buying flood insurance.
“From January through now I’ve written more new flood insurance policies than I have in my 30-year career,” said Becky Carlson, an agent with Associated Insurance Services who has been in Boise since 2008.
She said a flood insurance policy for a $250,000 home in a high-risk flood zone to cover the building and its contents is about $2,400 a year.
She said some homeowners might have delayed buying the insurance policies that come with a 30-day waiting period before they go into effect. But she said it’s not too late, as federal officials expect the Boise River to run high into June. It’s unclear if the river will be raised again.
“We don’t know at this time,” Baltrusch said. “There’s always that possibility.”
The Green Belt, a path that runs along the river in Boise and downstream cities, is typically filled with walkers, runners and bikers. But now it’s inundated and closed in multiple areas, with some areas partially washed away or in danger from falling trees that have root systems underwater.
A four-member emergency management flood-fight team from the U.S. Army Corps of Engineers found river water seeping last week through the shoreline into gravel mining pits.
The agency said that if the river breaks through, it could reroute the current and put lives and property at risk, including the Boise wastewater treatment plant. As a result, workers are building a temporary levee in the area.
Was this article valuable?
Here are more articles you may enjoy.