[ Hanke Pit Dam ]

Project :

  
Slope Stability of the Hanke Pit #13 Dam
Location :  
Warrenton, Missouri
Date :  
 
   
 

Harbison-Walker Refractories Company mines clay from several sites in east central Missouri for use in the manufacture of bricks. The Hanke Pit #13 dam was constructed to impound water in an old clay pit that was excavated by Harbison-Walker. The earth dam encircles the clay pit and is located on top of a ridge. The only runoff into the reservoir is the rain that falls within the dam. Harbison-Walker did not obtain a construction permit from the Department of Natural Resources (DNR) to build the dam. It was their understanding that the dam was too small to be regulated by the state. Staff from DNR's Dam and Reservoir Safety Program made a site visit in 1997 and determined the height of the dam to be 42 feet. Harbison-Walker was subsequently notified that they would have to obtain a safety permit and show that the dam has adequate spillway capacity and meets the slope stability criteria in the regulations.

WILSON HYDRO was retained to prepare a safety permit application which consists of performing an engineering survey of the dam, analyzing the stability of the embankment, evaluating the adequacy of the spillway and preparing a maintenance and operation plan for use by the owner.
WILSON HYDRO teamed with J. Larry Hubbard, consulting engineer, to complete this project for Harbison-Walker Refractories Company. The Hanke Pit #13 Dam was inspected and an engineering survey of the embankment and open channel spillway was performed. Soil samples of the embankment and foundation were obtained and submitted to a geotechnical testing laboratory for analysis. Both an overtopping analysis and a slope stability analysis of the dam were performed. The results indicated that the spillway capacity was adequate and the dam met the minimum factors of safety for slope stability. An engineering report and safety permit application were prepared and submitted to the state for approval.

By working closely with Dam and Reservoir Safety Program engineers and completing the work in a timely manner, WILSON HYDRO was able to successfully obtain a safety permit for Harbison-Walker Refractories Company.