Canyon Lake, formerly known as Canyon Reservoir, is on the Guadalupe River twelve miles northwest of New Braunfels in northern Comal County (at 29°52' N, 98°12' W). The project is owned by the United States government and operated by the United States Army Corps of Engineers, Fort Worth District. The local cooperative agency is the Guadalupe-Blanco River Authority, which, for paying part of the cost, has rights to the conservation storage space and control over the use and release of conservation water. The lake, formed by a rolled earthfill dam 6,830 feet long, is used for flood control, water conservation, and recreation. Construction of the dam was started on June 27, 1958, and impoundment of water began on June 16, 1964. The general contractor was Tecon Corporation of Dallas. The crest of the spillway is 943 feet above mean sea level, and the conservation storage capacity is 382,000 acre-feet with a surface area of 8,240 acres and a sixty-mile shoreline at 909 feet above mean sea level. Stored water is used for municipal, industrial, and irrigation purposes and for the development of hydroelectric power downstream. The drainage area above the dam is 1,432 square miles.
The construction of the dam and subsequent growth of the area surrounding the lake are among the most significant developments in twentieth-century Comal County history. Inundating a portion of the Guadalupe River valley cost the area productive farm and ranch land as well as two rural communities-Cranes Mill and Hancock-but it also stimulated development that transformed the economy and demography of the county. After the lake was filled north central Comal County became one of the largest population centers in Central Texas and the focus of a resort and tourist industry that rivaled manufacturing and agriculture in importance to the county economy. The dam made possible land development along the lake shore and in the area downstream, which for the first time was protected from periodic flooding. Even as the lake was filling, the first residential subdivisions-including Canyon Lake Hills and Canyon Lake Village-began attracting permanent and temporary residents. By 1967 there were forty-six subdivisions on the shores of Canyon Lake and fourteen more in the hills surrounding it. By the mid-1980s more than eighty neighborhoods had been built, and estimates of the permanent population of the lake area ranged from 12,000 to 15,000. Seven lakeside public parks and two public marinas served thousands of weekend visitors. Residents and tourists supported a variety of new businesses and service industries that transformed the former farm and ranch communities of Sattler and Startzville into thriving commercial centers and occasioned the new town of Canyon City. In the late 1980s two schools and thirteen churches served the permanent residents of the lake area. The Canyon Lake community, forty-eight miles from San Antonio and fifty-six from Austin, continued to attract new commuter, retired, and weekend residents.