The Laramie-Poudre Tunnel is an early transmountain

tunnel A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube cons ...

in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

. The tunnel transfers water from the west side of the

Laramie River The Laramie River is a tributary of the North Platte River, approximately long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed March 21, 2011 in the U.S. states of Colorado and Wyoming. ...

basin, which drains to the

North Platte River The North Platte River is a major tributary of the Platte River and is approximately long, counting its many curves.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed March 21, 2011 In a ...

, to the east side

Cache la Poudre River The Cache la Poudre River ( ), also known as the Poudre River, is a river in the state of Colorado in the United States. Name The name of the river () is a corruption of the original Cache à la Poudre, or "cache of powder". It refers to an ...

basin that drains to the

South Platte River The South Platte River is one of the two principal tributaries of the Platte River. Flowing through the U.S. states of Colorado and Nebraska, it is itself a major river of the American Midwestern United States, Midwest and the American Sout ...

. The tunnel is about long with variable diameters with a minimum diameter of about . 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 elevation with about a 1.7 degree down slope.Brunton, D. Transactions of the Institute of Mining Engineers Vol XLIII 1913 p.100 The Laramie River lies about higher than the Cache La Poudre River at this location separated only by a mountain ridge. The Laramie-Poudre Tunnel is located about west-northwest of

Fort Collins, Colorado Fort Collins is a home rule municipality that is the county seat and the most populous municipality of Larimer County, Colorado Larimer County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 359 ...

, about south of the

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

border and about north of

Rocky Mountain National Park Rocky Mountain National Park is an American national park located approximately northwest of Denver in north-central Colorado, within the Front Range of the Rocky Mountains. The park is situated between the towns of Estes Park to the east and ...

. It was built between 1909 and 1911 for the Laramie-Poudre Reservoirs & Irrigation Co. to convey water from the

to the

Poudre River The Cache la Poudre River ( ), also known as the Poudre River, is a river in the state of Colorado in the United States. Name The name of the river () is a corruption of the original Cache à la Poudre, or "cache of powder". It refers to an ...

for

Front Range The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the central portion of the U.S. State of Colorado, and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountere ...

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-Poudre, nearly opposite the eastern portal. "Repauno 60-per cent. gelatine" was used along with German Insolid and Z.L. fuse were used for blasting, with exception where the granite was really hard and tough. There were about 60 people employed with skills ranging from helpers, muckers, mechanics, stable-helpers, blacksmiths, book keeper and foremen. These were arranged in an 8-hr shift. Court battles between

and

over water rights prevented operation until 1914 (Case 1995). As a result of the court battles the tunnel is restricted to a maximum of of water from the Laramie river instead of its designed . Most of the flow occurs during the peak snow melt season of mid May to mid July. The Laramie-Poudre Tunnel typically transfers about 14,000 acre ft (17,300,000 cubic meters) from the Laramie River basin to the Cache La Poudre Basin. Agriculture users typically use about 450,000 acre ft and municipal users use a further 75,000 acre ft in the Cache La Poudre drainage basin. In the spring of 2000 after almost 90 years of use, part of the tunnel collapsed, requiring extensive rebuilding of part of the tunnel. This rebuild cost $4,500,000 and took from November 2000 to May 16, 2001.

Greeley, Colorado Greeley is the home rule municipality city that is the county seat and the most populous municipality of Weld County, Colorado, United States. The city population was 108,795 at the 2020 United States Census, an increase of 17.12% since the 2010 ...

partnered with North Weld County Water and the Fort Collins-Loveland Water District to purchase the Laramie Poudre Tunnel in 2006.Laramie Poudre Tunnel Purchas

Accessed 7 Sep 2011

References

{{reflist, 30em Tunnels in Colorado Water tunnels in the United States Irrigation projects Irrigation in the United States Tunnels completed in 1911 Transportation buildings and structures in Larimer County, Colorado 1911 establishments in Colorado