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Damn good idea. Being part Engineer and part Boy Scout, I just love Patty May, the program chairman. Our program for November was a trip to the massive structure (1,864,000 cubic yards) that holds back the running waters of the Colorado. About twenty-five of us met at the power generation building at the bottom. We toured the control center, went down below where the generators were turning, and then walked the tunnels inside the dam. One past president showed up in a flordora. When we were in the tunnels, I could just picture him being chased by a wall of rushing water and body surfing until he could catch the lower rung on a ladder. Lee Bowman led the tour of the facility. He had retired from active work at the dam several years ago, but would come back to lead public tours. While in the generator room, we were amazed at the slow speed of the water wheel. It turned at 144 rpm, which is a lot slower than a turbine. Of course while we were inside the dam, all the lights had to be turned out to be sure we could appreciate how dark it could be. There was one job that seemed hard to fill. Every quarter someone has to climb down a 90 foot latter to the base of the structure. There are about 20 points to check. ------------------------------------------------------------------------ Mansfield Dam which is owned by the LCRA and creates Lake Travis: Constructed from 1937-41 by the LCRA and the U.S. Bureau of Reclamation, Mansfield Dam serves as the only flood control structure for the lower river basin. Mansfield and Lake Travis also provide water storage and hydroelectricity for the LCRA. The dam was originally named after the nearby settlement of Marshall's Ford (and the U.S. Army Corps of Engineers still refers to the structure as Marshall Ford Dam). It was renamed in 1941 for U.S. Representative J.J. Mansfield, who assisted in development of the project. The dam contains 24 floodgates. The dam is 266.41 feet high. The length is 7,089.39 feet. At the base, it is 213 feet thick; at the top, it is 30 feet thick. The original Ranch Road 620 is built on top of the dam. The road and adjoining protective walls bring the actual height of the dam to 274 feet. The power plant's three units provide a generating capacity of 93,000 kilowatts. The reservoir is 63.75 miles long, and its maximum width is 4.5 miles. The lake covers 18,929 acres, and its capacity is 1,170,752 acre-feet. All figures are for the reservoir filled to the top of the conservation and power pool - elevation 681.1 feet msl. Flood control: Mansfield Dam is the only structure in the Highland Lakes chain specifically designed to contain floodwaters. When the elevation of the lake exceeds 681 feet msl, the LCRA begins floodgate releases under the direction of the U.S. Army Corps of Engineers; the amount and duration of the releases will vary, depending upon the weather and flood conditions above and below the dam. Lake elevation when full: 681.0 ft. msl Normal operating range: at or below 681.0 ft. msl Elevation of overflow spillway: 714.0 ft. msl 100 year flood level at dam: 716.0 ft. msl Top of dam: 750 ft. msl Lake volume: 1,170,752 acre-feet Total discharge capacity: 121,080 cfs 24 floodgates @ 4,770 cfs each 3 turbines @ 2,200 cfs each Historic high: 710.4 ft. msl on Dec. 25, 1991 Historic low: 614.2 ft. msl on Aug. 14, 1951 River miles from Gulf of Mexico: 318 miles |