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Geophysical Feasibility Study to Identify Signs of Chimney Drain/Drainage Blanket Clogging in Canyon Dam Canyon Lake, Comal County, Texas

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Technical Report

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Engineer Research and Development Center Vicksburg United States

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To determine the feasibility of using geophysical methods for detectingidentifying areas that may be clogged within the chimney drain andor drainage blanket. A geophysical feasibility study was conducted 18-22 AUG 2015 at Canyon Dam, located in Canyon Lake, Comal County, Texas, by Dr. Janet Simms and Ms. Katie Martin of the Geotechnical Engineering and Geosciences Branch GEGB, Geotechnical and Structures Laboratory GSL, U.S. Army Engineer Research and Development Center ERDC, Vicksburg, Mississippi. The survey was conducted at the request of the Geotechnical Branch, U.S. Army Corps of Engineers USACE, Fort Worth District SWF. The Fort Worth District point of contact was Ms. Sarwenaj Ashraf. The investigators were assisted by Canyon Lake office personnel Mr. Marcus Schimank, Canyon Lake Manager, and Mr. John Jacobs, CE Technician. Mr. Lucas Walshire, ERDC, provided the modeling results discussed below. Canyon Dam is located at river mile 303.0 on the Guadalupe River about 12 miles 19 km northwest of New Braunfels, Texas. It is a rolled earth-fill embankment with a core comprised of a well-compacted, high-plasticity material CH and an embankment shell constructed of well-compacted CL material. The crest length measures 4,410 ft 1,344 m and has a height of 224 ft 68 m at elevation 972.87 ft 296.5 m. Construction of the dam was completed in 1964. The chimney drain extends vertically from the drainage blanket to approximately 31 ft 9.5 m below the crest to elevation 943.3 ft287.5 m along the length of the dam. The chimney drain is 10 ft 3 m wide, and its center is located 25 ft 7.6 m east of the crest centerline. The drainage blanket is 5 ft 1.5 m thick with its bottom located at elevation 780.3 ft 237.8 m. The filter material consists of processed stone obtained from nearby limestone quarries.

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  • Civil Engineering

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