The U.S. Army Corps of Engineers will begin work Saturday to build a 4,300-foot temporary levee between the Boise River and a gravel pit to form a key flood barrier in Ada County.
The privately owned gravel pit is near the east end of Eagle Island, not far from the Island Woods and Two Rivers neighborhoods.
Crews will be constructing the levee with HESCO bastions that are 4 feet tall, made of heavy-duty wire caging and filled with sand. Engineers say the levee is meant to keep high water out of the gravel pit, but they are anticipating the ground around the pit will fail, according to Ada County officials.
That means the residents who live west of the area might need to evacuate.
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Some residential roads and portions of Eagle Road, over the north and south channels of the Boise River, could be covered with water and impassable.
If this situation does occur, the Ada County Sheriff’s Office will use the CodeRed warning system to let residents know what’s happening and direct them to which routes will get them out safely.
Ada County on Friday encouraged residents in the area to create a plan for evacuation for their families, the elderly in the area, and pets and livestock.
Boise River flows remain high. On Friday evening the river’s flow at Glenwood Bridge was 8,260 cubic feet per second, which is above flood stage. The river is expected to reach 8,500 cfs by next week at that bridge.
Greenbelt closures and detours will remain in place during this time.
Updates can be found on the county’s flood website as well as the CodeRed alert link. The National Weather Service continues to have a flood warning in place for Ada and Canyon counties, and some rain is in the forecast through Tuesday.