Laramie-Poudre Tunnel

The Laramie-Poudre Tunnel is an early transmountain tunnel in the U.S. state of Colorado. The tunnel transfers water from the west side of the Laramie River basin, which drains to the North Platte River, to the east side Cache la Poudre River basin that drains to the South Platte River. The tunnel is about 11,500 feet (3, 500 m) long with variable diameters with a minimum diameter of about 5.3 feet (1.6 m). The diameter varied due to the different material mined through and the erosion of almost 90 years of water flow. It is located at about 8,400 feet (2, 600 m) elevation with about a 1.7 degree down slope. The Laramie River lies about 225 feet (69 m) higher than the Cache La Poudre River at this location separated only by a mountain ridge. The Laramie-Poudre Tunnel is located about 45 miles (72 km) west-northwest of Fort Collins, Colorado, about 20 miles (32 km) south of the Wyoming border and about 25 miles (40 km) north of Rocky Mountain National Park. It was built between 1909 and 1911 for the Laramie-Poudre Reservoirs & Irrigation Co. to convey water from the Laramie River to the Poudre River for Front Range irrigation. The tunnel was driven for the purpose of conveying through the divide 800 cu.ft of water per second. "Work on the power-plant for operating the tunnel was begun Dec 1st 1909. The Hydro-electric power-plant was erected on the west bank of the Cache-la-Poudr

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).