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Bureau of Reclamation

Gunnison Tunnel
Society: ASCE Main Category: Civil Sub Category: Tunnels Era: 1900-1909 DateCreated: 1909 Montrose State: CO Zip: Country: USA Website: Creator: Bureau of Reclamation

At its completion, the 5.8-mile Gunnison Tunnel under western Colorado's Vernal Mesa was the longest irrigation tunnel in America. It carried water from the Gunnison River to the Uncompahgre Valley to irrigate 146,000 acres of cropland. 

Work on the 30,582-foot tunnel was first performed manually. Adverse geological conditions provided great challenge for this pioneering project. The drilling crews had to deal with clay, sand, shale, and a badly fractured fault zone. 

Image Credit: Public Domain; Produced prior to 1/1/1923 Image Caption: Gunnison Tunnel Era_date_from: 1909
Grand Coulee Dam
Society: ASCE Main Category: Civil Sub Category: Dams Era: 1940-1949 DateCreated: 1941 Columbia River Grand Coulee State: WA Zip: 99133 Country: USA Website: Creator: Bureau of Reclamation

The massive Grand Coulee Dam, on the Columbia River, is the largest concrete structure in the U.S., the largest hydroelectric facility in the U.S., and the sixth-largest hydroelectric facility in the world. It provides irrigation for up to 1.1 million acres of agricultural lands and the hydroelectric complex maintains a generating capacity of 6.8 million kilowatts. It also serves as the primary flood control for the Columbia River basin (with a capacity of 5.18 million acre-feet of water) and provides recreational opportunities on the 150-mile-long Franklin D. Roosevelt Lake.

Image Credit: Courtesy Flickr; //lucylu (CC BY-ND 2.0) Image Caption: Grand Coulee Dam Era_date_from: 1941
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