Release no. 17-025
Omaha Public Affairs Office
Omaha, NE—Pipestem Reservoir is currently at pool elevation 1443.5 feet, which is 1.0 feet above the base of the flood pool. Inflows are currently near 120 cubic feet per second (cfs) with a reservoir release near 100 cfs. Jamestown Reservoir is currently at pool elevation 1430.7 feet, which is 0.3 feet below the base of the flood pool. Inflows are near 50 cfs with a small reservoir release of 13 cfs. The maximum combined release from the reservoirs is not expected to exceed 450 cfs this summer; however, additional snow accumulation in the next month or significant spring or summer rainfall could necessitate release levels of 750 cfs or higher.
The National Operational Hydrologic Remote Sensing Center’s (NOHRSC) model for the upper James River and Pipestem Creek basins currently show an average of 0.5 – 1.5 inches of snow water equivalent (SWE), down from the peak modeled SWE values averaging between 4.5 – 5.5 inches. Thawed soils have allowed for infiltration of some of the snowmelt runoff, but saturated soil conditions could lead to increased baseflow into next year.
Pipestem Dam initiated a winter release of 5 cfs to benefit water quality in early January this year. Inflows into the reservoir kept the pool elevation above the uncontrolled weirs and slightly in the flood pool over the winter. In mid-February the reservoir began to rise from early snowmelt. The pool peaked at an elevation of 1444.9 ft, almost 2.5 ft into the flood pool. Inflows peaked from the early snowmelt at over 500 cfs on February 21 before beginning to decline.
Releases from Pipestem during the early event increased as the pool rose, reaching just over 200 cfs on February 22. Releases were held near 200 cfs until March 6, when the gates were adjusted to allow for a maximum release near 100 cfs as inflows keep the reservoir in its flood pool. Jamestown Dam has been on a rising trend since the mild temperatures began in mid-February. A release from Jamestown Dam will be initiated when necessary this spring in order to evacuate any accumulated Jamestown Reservoir flood storage. Pipestem Reservoir flood storage will be primarily evacuated in June, July, and August to allow for evacuation from Jamestown reservoir by June 1.