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Corps surveys the Keystone Dam

Published March 4, 2020
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IN THE PHOTO, a scanning total station (Tremble SX10) collecting data at the Keystone Dam.

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IN THIS PHOTO, Survey Technician Phil Pettit collects survey data needed for the Keystone Dam Safety Modification Study.

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IN THIS PHOTO, a Google Earth image of a Keystone Dam right abutment.

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IN THE PHOTO, a Google Earth image of the Keystone Dam survey areas.

The Memphis District U.S. Army Corps of Engineers continues to perform survey support for districts outside of the Mississippi Valley Division.

Recently, Surveyors Josh Beam and Phil Pettit from the Memphis Survey Section completed a survey of the Keystone Dam, which is located west of Tulsa, Oklahoma on Keystone Lake near the community of Sand Springs.

“The surveys were collected to support the ongoing Keystone Dam Safety Modification study, which is being conducted in order to identify risks to the dam and to the public” Geospatial Section Chief Bill Snapp said.

Keystone Lake reached a record pool elevation during a spring flood event over a three month timeframe in 2019. Inspectors reported several damages were reported on the downstream side of the dam including at both abutments (the survey areas).

“Each abutment displayed areas of light to heavy seepage, and a longitudinal tension crack in embankment soils running parallel to a rock outcropping was observed along the right abutment indicating potential movement in the embankment,” Snapp explained. “Heavy surface runoff over and through the rock outcropping were also observed over the flood timeframe. This in combination with a faulty French drain were thought to contribute to the distress in the abutment.”

The Tulsa District received supplemental flood funds to repair several items including the slide area along the right abutment. They will also install a new seepage collector and measurement systems along both abutments.

“An additional dam modification study is being performed to further drive down the incremental risk due to seepage and piping along both abutments,” Snapp added. “The purpose of the project was to set survey monuments that will aide in establishing proper surveying control and to collect topographic data including cross sections, drains, utilities and other physical features. This information will assist engineers in performing remediation designs for the Dam Modification study.”

The Tulsa District needed a completed survey within 30 days of the request in order to support the project schedule.

“The Memphis Survey Section completed the survey and submitted the results within 14 days of the request,” Snapp said. “The work was completed on time and thousands of dollars under budget.” 

This recent survey is just another great example of the exceptional work our Survey Team continues to do day in and day out.