was built in 1901. In Hells Canyon, a cascade of dams produce hydroelectricity from the river's steep fall over a comparatively short distance. Finally, a third cascade of dams, from Hells Canyon to the mouth, facilitates navigation. Many different government and private agencies have worked to build dams on the Snake River, which now serve an important purpose for people living in the drainage basin and trade of agricultural products to Pacific seaports. The Minidoka Irrigation Project of the U.S. Bureau of Reclamation, created with the passage of the Reclamation Act of 1902, involved the diversion of Snake River water into the Snake River Plain upstream of Shoshone Falls in order to irrigate approximately in the Snake River Plain and store of water in Snake River reservoirs. The first studies for irrigation in the Snake River Plain were conducted by the United States Geological Survey in the late 19th century, and the project was authorized on April 23, 1904. The first dam constructed for the project was Minidoka Dam in 1904; its power plant began operating in 1909, producing 7 MW of electricity. This capacity was revised to 20 MW in 1993. Jackson Lake Dam, far upstream in Wyoming's Grand Teton National Park, was built in 1907 to raise Jackson Lake for providing additional water storage in dry years. American Falls Dam, upstream of Minidoka, was completed in 1927 and replaced in 1978. As the dams were constructed above Shoshone Falls, the historical upriver limit of salmon and also a total barrier to boats and ships, no provisions were made for fish passage or navigation. Several other irrigation dams were also built - including Twin Falls Dam and Palisades Dam. The Hells Canyon Project was built and maintained by Idaho Power starting in the 1940s and was the second of the three major water projects on the river. The three dams of the project, Brownlee Dam, Oxbow Dam and Hells Canyon Dam, are located in upper Hells Canyon. All three dams are primarily for power generation and flood control and do not have fish passage or navigation locks. Brownlee Dam, the most upriver dam, was constructed in 1959 and generates 728 megawatts (MW). Oxbow Dam, the second dam in the project, was built in 1961 and generates 220 MW. The dam was named for a bend in the Snake River, shaped like an oxbow. Hells Canyon Dam was the last