Rapid Creek water flow levels back to normal after repairs at Pactola Reservoir

RAPID CITY, S.D. —Water flow out of Pactola Reservoir is back up to a more-normal 30 cubic feet per minute (cfm) after repairs to a water regulation gate were completed Dec. 8.

Last week, the Bureau of Reclamation began lowering the water levels into Rapid Creek to conduct repairs to the Pactola Reservoir left regulating gate. In coordination with Rapid City, the Bureau of Reclamation temporarily lowered levels to 11 cubic feet per second to facilitate required repairs to the dam.

Gate number 4 at Pactola Reservoir.

Concrete cavitation was identified during an inspection in November near the left gate. On Monday, Dec. 5, planned repair work began, and the bypass was opened to allow continued flows while repairs were being made.

“After investigation of the cracking, special bonding was ordered to repair these damages. It is important to note that flows are being maintained through the bypass channel to continue to serve the greater Rapid City community,” said Dakotas Area Manager Joe Hall.

The repairs are necessary due to the location of cavitation and cracking. Further cavitation could lead to larger repairs on the gate itself.

The Bureau of Reclamation maintains and controls releases in conjunction with Rapid City. In addition, an abnormally dry season has contributed to lower flows in Rapid Creek.

“We expect the materials and repairs to be completed by the end of the week,” said Hall. “At that time, we expect flows to increase to 30 cubic feet per second.”

Pactola Dam and Reservoir are part of the Rapid Valley Unit which provide irrigation water for about 8,900 acres of farmland, municipal and industrial water supplies for Rapid City and Ellsworth Air Force Base, flood control benefits for the local area, and wildlife benefits are provided through cooperative efforts between the Bureau of Reclamation and other federal and state agencies.

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