WALLA WALLA, Wash. – U.S. Army Corps of Engineers operations staff began diverting water from Mill Creek to Bennington Lake today, April 19, 2018, in preparation for the upcoming summer recreation season.
The lake, which was drained in the fall for maintenance and seasonal flood-risk-management operations, is currently at about 1,188 feet above sea level. The Corps determines when to fill the lake based on snowpack and the likelihood of needing capacity in the lake to store flood water to reduce the risk of flooding for the City of Walla Walla. Refilling the lake has typically occurred in early March, but this year, snowpack and rainfall did not meet refill conditions until April. Flows in Mill Creek also influence refill operations, because water level in the creek needs to be low enough for Corps staff to install fish screens which help prevent ESA-listed steelhead and bull trout from being diverted to and becoming trapped in the lake.
“When the lake is filled to recreation level, it will be at 1,205 feet above sea level, 17 feet higher than where it is now,” said Mill Creek Dam and Bennington Lake Park Ranger Jeremy Nguyen.
While the lake is being filled the intake canal will have up to 3 inches of water in it. Visitors are allowed to cross the canal during this time, but they can avoid getting their feet wet if they cross at the diversion dam. It could take about 10 days to fill the lake to its target level, depending upon springtime flow conditions in Mill Creek, he added.
Once the lake reaches the boat ramp, Washington State Department of Fish and Wildlife staff and program partners from the Tri-State Steelheaders will be able to stock the lake with rainbow trout from the Lyons Ferry Fish Hatchery, Nguyen noted.
Recreation areas associated with Walla Walla District’s Mill Creek Dam and Bennington Lake, located just east of Walla Walla, Wash., include Bennington Lake, the Mill Creek Recreation Trail and Rooks Park. The lake and trail are open year-round. Rooks Park is seasonally open to vehicle traffic April 1 through mid-Oct., but accessible year-round to pedestrians.
Corps recreation planners invite the public to "play it safe" while having some warm-weather fun. Although above-water temperatures are becoming warmer, springtime water temperatures can be cold enough to cause swimmers to develop hypothermia – a severe lowering of core body temperature. State boating, hunting and fishing regulations apply to visitors at Corps sites. Hunting on Corps property is allowed in designated areas and seasons only. Boaters should ensure personal floatation devices are on board for each person – children 12 and younger are required to wear personal floatation devices when in a boat. Only paddle-powered or non-combustible-engine-powered boats are allowed on the lake.
For more information on Corps parks, visit www.nww.usace.army.mil/corpsoutdoors
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