We can not believe that some one has not posted a cache to this historic location previously! There is an Earthcache at the East (Entry) portal inside of the Black Canyon of the Gunnison National Park which provides a lot of the history of the Tunnel, but not here. No longer is that the case!
The actual tunnel head wall is located .4 mi East (marked as a point of interest) and may not be accessible at all times. It is difficult to see as it opens into the canal well below ground level and is surrounded by dense brush on extremely steep sides. Best seen if you go east past the headwall and around to south side of canal and back west several hundred feet to a bend in the canal such that you can look straight in to the tunnel outlet - see photos along sides. During summer months when the water is flowing, the head wall is mostly submerged.
At one time there was an entire town located in this area, complete with hospital, school, Post Office, Administration Complex, stores, salons, workers homes, and all the other accoutrements of a small town. The building of the Gunnison Tunnel was coordinated from here as well as the digging from this end of the 5.8 mile long tunnel which was 8'w x 10'h, large enough to drive a vehicle through. Digging was also done from the East end and in both directions from a shaft sunk in the center of the tunnel - done to speed construction time of 2+ ys. At the time of it’s construction, it was the longest irrigation tunnel in the world and is a National Historic Civil Engineering Landmark.
YEARS and multiple survey attempts were made in the Gunnison Gorge before the 1st successful survey of the Black Canyon was completed just to determine the best starting point of the tunnel. More time yet to survey the tunnel itself from portal to portal, up and over the shear cliffs of the gorge. Everything had to be precise to "make ends meet!" It was 20yrs after the completion of the tunnel before the first motorized vehicle made it down into the east portal site over a road with 30% grades, horses were used to pull it back out!
Prior to the Gunnison Tunnel, there was not sufficient water to irrigate the whole of the Uncompahgre Valley and much of it was barren. This project provided enough water for the entire valley making it one of the most productive farmlands in the entire US. For years, local produce regularly took the Blue Ribbon at World Fairs, as well as national, regional and state. For more information on the construction of the tunnel and the impact on the valley below, see these links;
http://www.nps.gov/cure/learn/historyculture/eastportal.htm
http://www.nps.gov/nr/travel/ReclamationDamsIrrigationProjectsAndPowerplants/Gunnison_Tunnel.html
The tunnel building project was one of the first five projects undertaken by the newly created "Bureau of Reclamation". The government put up the bulk of the money (interest free) and area water users the rest. Through sale of the water the government was repaid at which time the management reverted to the local water users association, although with some residual government oversight.
The location of the cache is at a newly constructed "pond" that diverts the water from the original ditch (immediately beside the cache) into an underground pipe that runs near dead level and then drops approximately 100' into a low head hydro electric plant that is approximately 1/2 mile west of the cache and hidden by the berm over the pipe on which you will be standing. A second similar plant is planned and in the permit process further down stream, a three-fer! Two hydro generating plants and still 100% of the water to the farmers that they had before!