Above average releases at Boysen and Anchor

Releases from Boysen Dam to the Wind River are currently at 5,500 cubic feet per second (cfs). Based on current operating projections and the expectation of near record runoff, Boysen Reservoir will be lowered approximately another ten feet to near elevation 4,700 feet in May. Once the snowmelt runoff begins, Boysen Reservoir will be managed to fill the reservoir to an elevation of 4724.5 feet in July. As the reservoir experiences peak run-off, releases from Boysen Dam to the Wind River are expected to reach flows up to 6,500 cfs.

Bureau of Reclamation (BOR) Wyoming Area Manager Carla Ronca said, “Steps are being taken to make room for the snowmelt runoff that is expected to come into the Bureau of Reclamation’s Boysen Reservoir over the next few months. Moving water downstream below Boysen Reservoir now will reduce the peak of downstream flows that would be experienced otherwise.”

Recreationists are encouraged to use caution regarding changing reservoir levels and high river flows. Conditions can change rapidly during runoff and the Bureau of Reclamation is coordinating with other federal, state, and local officials regarding reservoir levels and river flows.

According to a report on the dam, presented by Hot Springs County Emergency Management Coordinator Bill Gordon during the May 2 meeting of the Hot Springs County Commissioners, releases continue at 5,500 cfs and there is a plan to maintain that. The reservoir itself is down to 62 percent capacity, with the “full capacity” elevation being 4,725 feet. At a height of 4,707 feet, there is 18 feet of storage available in the lake.

The spillway elevation is 4,700 feet, and once the lake drops to that elevation the BOR is unable to release any more water. The April 1 prediction of snowmelt runoff into Boysen was 1.1 million acre feet, over 200 percent of normal, which could be record-breaking this year. The May prediction is currently being calculated, but is expected to be higher.

With increased inflows there will be higher releases, which could potentially cause significant flooding which would require evacuations. Timing isn’t known, as runoff from the Wind Rivers hasn’t begun and Boysen continues to lower. If problems occur in the county regarding the Big Horn River flows they could start around June 1-15.

Also being looked at is Anchor Reservoir. According to a report, as of May 1 the snow/water equivalent at the Owl Creek Snotel is at nine inches. It’s important to note the snotel is often finished melting before the high country west of it even begins runoff.

Gordon has expressed concern about the Anchor Dam area, as the dyke is about 25 feet high and they will not let water go over it, so water could be released at higher rates to protect it.

The Washakie Needles are 12,523 feet. How much snow is in the high country is currently not known, but there’s no reason to think it’s above normal.

The BOR is currently in discussions with the State Engineer’s Office to determine what changes might be necessary to normal operating procedures for 2017 spring runoff.

It is anticipated releases from Anchor Dam might be higher and earlier than normal, to try to avoid high Anchor releases coinciding with uncontrolled runoff expected from the North Fork of Owl Creek.

Emergency Management will provide additional information in the future, from the BOR, as to Anchor strategy, and get that information to the public, especially those living along Owl Creek.

Gordon further shared an action plan in regarding the runoff and increased flows. According to it, information about the latest data and runoff predictions will be shared with county jurisdictions and agencies.

Emergency Management has solid communication with several agencies in the county, as well as BOR, State Engineer’s Office, National Weather Service, Wyoming Highway Patrol, Wyoming Department of Transportation, Wyoming National Guard, Wyoming Red Cross. Should the need arise, conference calls will be facilitated by Emergency Management with some or all of these agencies in order to focus specifically on Hot Springs County and function with current and confirmed information. There is also access to a sandbag machine, if needed.

Using data and predications from federal and state sources, contingency plans will be developed as soon as possible to maximize preparedness and response in event of an emergency.

Gordon has said the Wind River and Bighorn River might be able to handle flows of up to 10,000, even 12,000, cubic feet per second, but at that point there would definitely be some water running onto properties and into streets.