Skyline Ditch

The Skyline Ditch, one of the first successful transbasin diversions in the Cache la Poudre River Basin, distributes water from the Laramie River and its tributaries to the north end of Chambers Lake. 1 In July 1891, Larimer County Ditch Company (later Water Supply and Storage Company) began building the ditch, the brainchild of Franklin C. Avery, to supplement Cache la Poudre River flows. During the first year of work, William Rist served as project engineer and John McNabb as foreman, and the first diversion of Laramie River water arrived in 1894. Water Supply and Storage Company completed the project in 1895 with a final length of five miles. The project cost approximately $90,000. Laborers performed the ditch digging work by hand. Work was hard, as crews constructed the ditch along a steep, 45-degree angle on mountain slopes. Rist originally made the grade of the ditch relatively steep in order to make it self-cleaning, but this proved problematic. Water flowed to swiftly, which cut out banks along curves. When in 1892 Water Supply and Storage Company put Engineer Nelson in charge of the project, he reduced the ditch’s grade, added a 100-foot long tunnel, and placed several thousand feet of flume pipe. The result was a serviceable ditch that required only occasional repairs and maintenance. Water Supply and Storage Company enlarged the ditch in 1927 to a width of eight feet at the bottom, twelve feet at the top, and a depth of four feet. 2

In 1911, the Skyline Ditch’s status as a transbasin diversion brought it into the middle of a larger interstate disagreement between Wyoming and Colorado over who could claim Laramie River water, which began in Colorado before flowing into Wyoming. In Wyoming v. Colorado (1922), the U.S. Supreme Court based its ruling on both state’s prior appropriation laws. Colorado could not divert the volume of water it desired from the Laramie River in 1911, but certain early Colorado transbasin diversions, like that of the Skyline Ditch, were allowed and left untouched. Wyoming v. Colorado and similar cases prompted leaders in Colorado and surrounding states to begin talks for cooperative interstate use agreements (compacts) for rivers that flowed out of Colorado and into other states in the 1920s. 3

  1. The Cameron Pass Ditch, built in 1882, was the first.
  2. Stanley R. Case, The Poudre: A Photo History (Bellvue, CO: Stanley R. Case, 1995), 221-222; E. S. Nettleton, The Reservoir System of the Cache La Poudre Valley (Washington: Government Printing Office, 1901), 25; Ansel Watrous, History of Larimer County Colorado (The Old Army Press, 1911), 158; Norman Walter Fry, Cache La Poudre: “The River” As Seen from 1889 to 1954 (Colorado: s.n.; reprint, 1954(?)), 23.
  3. Wyoming v. Colorado, 259 U.S. 419 (1922).

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