Corps stepping up water releasesPlans for initiating releases out of Jamestown and Pipestem reservoirs in North Dakota were announced Saturday in a news release by the Army Corps of Engineers. Due to abnormally high snow pack conditions in the basins upstream of the reservoirs, the corps expects high inflows into the two reservoirs this spring. Current snow pack conditions are similar to the record runoff year in 2009, the corps said. Releases from the reservoirs have been held at low levels in order to minimize downstream damages during the recent spring runoff.
Plans for initiating releases out of Jamestown and Pipestem reservoirs in North Dakota were announced Saturday in a news release by the Army Corps of Engineers.
Due to abnormally high snow pack conditions in the basins upstream of the reservoirs, the corps expects high inflows into the two reservoirs this spring. Current snow pack conditions are similar to the record runoff year in 2009, the corps said. Releases from the reservoirs have been held at low levels in order to minimize downstream damages during the recent spring runoff.
Releases from Jamestown Dam were increased from 13 cubic feet per second to 100 cfs Saturday. Releases from Pipestem Dam are at 90 cfs and were held at that level. Including runoff within the city of Jamestown, this resulted in a combined flow of approximately 200 cfs at the Jamestown stream gauge.
Reservoir releases will be gradually stepped up this week to a level of 750 cfs at the Jamestown stream gauge. The current forecasts by the National Weather Service and corps indicate that reservoir levels could be similar to 2009, when the spillway flows occurred at Jamestown Dam.
As long as levels are well below the crest of the emergency spillway at each project, the releases will be made through the outlet works with the maximum combined release of approximately 1,800 cfs. If forecasts indicate that pool levels may be near or exceed the spillway crests, the combined release may be increased to 3,200 cfs to decrease the probability of spillway flows, the corps said.
This is similar to operations last year, when combined releases of 3,200 cfs were initiated. During that event, Jamestown reservoir peaked 0.1 feet above spillway crest and Pipestem peaked 4.1 feet below spillway crest. Increasing the releases from 1,800 cfs to 3,200 cfs reduced peak pools at Pipestem by 3 feet and at Jamestown by 1.5 feet.
Contracts to build temporary emergency levees in Jamestown were awarded March 18-19. The work is expected to be completed within one week. The emergency levees are designed for a maximum combined release of 3,200 cfs.
Jamestown Reservoir was at 1,432.2 feet msl Saturday and Pipestem Reservoir was at 1,452.6 feet msl. Both have risen several feet over the last few days due to runoff from precipitation and snowmelt runoff, the corps said. In 2009, Pipestem peaked on April 23 at a record level of 1,492.3 feet msl, 5.3 feet higher than the previous record level of 1,487.0 feet msl in May, 1997. Jamestown peaked on April 26 at a record level of 1,454.1 feet msl, 8.2 feet higher than the previous record of 1,445.9 feet msl, also set in May 1997.
The crest elevation of the emergency spillway at Pipestem is 1,496.3 feet msl and 1,454.0 feet msl at Jamestown Dam.
Stages on the James River at Jamestown, Ypsilanti and Adrian are falling. Stages in LaMoure are expected to crest within the next few days, the corp said. The increase in releases has been delayed to avoid contributing to downstream flood crests.
Runoff in these areas has been slowed due to cold temperatures, and a second runoff event is expected when warmer temperatures return. Releases may be reduced if river stages begin to increase.
Temporary stream gauges have been installed at Ypsilanti, Adrian and Grand Rapids to monitor river levels. The travel time for the releases from the dams to reach to LaMoure, N.D., is one week, a week and half to Oakes, N.D., and two to three weeks to Columbia, S.D.
The corps, Bureau of Reclamation and National Weather Service will continue to monitor snow pack conditions and will provide updated forecasts and release plans as conditions change
Residents along the James River downstream from Jamestown should continue to monitor flood forecasts by the National Weather Service and make preparations as necessary to minimize damages from high river levels.
A James River bulletin is available on the Omaha District website at https://www.nwo.usace.army mil/html/op-e/index.html. It will be updated daily with current releases, river level conditions for the entire James River, and any planned changes in releases.