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Great Plains Region
Billings, Mont.
Media Contact:
Jeff Nettleton
(605) 394-9757
Arden Freitag
(701) 221-1250

Released On: October 15, 2009

Reclamation Releases Fall and Winter Operation Information for Western South Dakota Dams
The Bureau of Reclamation will be making adjustments to releases at various reservoirs in western South Dakota to position the reservoirs in anticipation of late winter and early spring inflows. Shadehill Reservoir near Lemmon, South Dakota, and Pactola, Deerfield, and Belle Fourche Reservoirs in the vicinity of and in the Black Hills are all near full. Jeff Nettleton, Chief of Facility O&M and Engineering Services for Reclamation's Dakotas Area Office in Rapid City, states that all four of these reservoirs will have reservoir release adjustments made to position them for inflows next spring.

"The adjustment of releases to position reservoirs occurs more often in wet years," said Nettleton. "Water year 2009 (October 1, 2008 to September 30, 2009) produced inflows to the six dams (operated by Reclamation's Rapid City Field Office) ranging from 54 percent of average at Angostura to 631 percent of average at Shadehill."

The following is the status of Reclamation's South Dakota Reservoirs and Keyhole Reservoir in northeastern Wyoming.

Shadehill

Shadehill Reservoir is at elevation 2268.3 which is 3.7 feet from full. The reservoir peaked in the flood pool last spring at elevation 2290.83 (second highest of record) nearly 19 feet above the full elevation of 2272.0 (when the reservoir starts to flow into the spillway). The inflows into Shadehill Reservoir were the highest since the dam was constructed in 1952. The inflows totaled 414,000 acre-feet with the previous high occurring in 1952 at 362,000 acre-feet. Discharge from the reservoir in water year 2009 was also the highest of record and totaled 389,000 acre-feet.

The present release from Shadehill is 70 cubic feet per second (cfs) and will be maintained into late fall with plans to decrease the release for the winter. This will allow the reservoir to fill next spring with average inflows.

Belle Fourche

Belle Fourche Reservoir is at elevation 2967.9 with a full elevation at 2975.0. Inflows into the reservoir were 125 percent of average for the water year. Belle Fourche ended the water year (September 30, 2009) at elevation 2967.51 which was the second highest of record (period of record is Reclamation's computer data base from 1952 to present). The highest end of September elevation since 1952 occurred in 1999 at 2969.44. Present inflows into Belle Fourche Reservoir are around 200 cfs.

Belle Fourche Dam is an off-stream storage reservoir located on Owl Creek. The reservoir is filled by diverting water from the Belle Fourche River at the Diversion Dam near Belle Fourche, through the Inlet Canal to the reservoir. The operational plan for the fall will be to fill the reservoir to elevation 2970.0. The Belle Fourche Irrigation District will then shut the Inlet Canal off, and as a result, the river flows will now be in the Belle Fourche River channel downstream of the Diversion Dam. Landowners along the river below the Diversion Dam will have flows in the river through the winter until the Inlet Canal is turned back on to fill the reservoir in the late winter or early spring. The turn on date is not expected until around early March depending on projected inflows.

Pactola

Pactola Reservoir at this time last year was at elevation 4573.5. The reservoir elevation is presently at 4578.7, with full elevation at 4580.2. The release is at 32 cfs and will probably stay at this release all winter. Last years winter release was around 16 cfs. Pactola inflows for water year 2009 were 114 percent of average. Inflows totaled about 40,000 acre-feet for water year 2009, with the average being approximately 35,000 acre-feet.

Deerfield Reservoir

Inflows to Deerfield for water year 2009 were 100 percent of average. The current release is at 11 cfs and the reservoir elevation is 5905.9. Deerfield is full at elevation 5908.0. The plan is to release around 11 cfs all winter. Last year the winter release was 8 cfs.

Keyhole Reservoir

Keyhole Reservoir is at elevation 4087.5. This elevation is 2.5 feet higher than last year at this time.Inflows to Keyhole for the water year were 79 percent of average and totaled 13,000 acre-feet. No releases from Keyhole were made during water year 2009.

Angostura Reservoir

The current elevation at Angostura is 3174.9 and the reservoir is 61 percent full. Last year at this time the elevation was 3173.2. Inflows into the reservoir for the water year were 54 percent of average. Angostura is a little over 12 feet from full and slowly rising in elevation.

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