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Chronology

1540
Alarcon discovers the Colorado River and explores its lower reaches. Cardenas discovers the Grand Canyon.

1776
Father Escalante explores the upper Colorado and its tributaries.

1857
Lt. J. C. Ives navigates the Colorado River and, with his steamboat The Explorer, reaches the end of Black Canyon.

1869
Major John Wesley Powell makes the first recorded trip through the Grand Canyon.

1902
President Theodore Roosevelt signs the Reclamation Act. Reclamation engineers begin their long series of investigations and reports on control and use of the Colorado

1905-1907
The Colorado River breaks into the Imperial Valley, causing extensive damage and creating the Salton Sea.

1916
Unprecedented flood pours down the Gila River into the Colorado, and flood waters sweep into Yuma Valley.

1918
Arthur P. Davis, Reclamation Director and Chief Engineer, proposes control of the Colorado by a Dam of unprecedented height in Boulder Canyon on the Arizona-Nevada border.

1919
All-American Canal Board recommends construction of the All-American Canal, and a bill is introduced to authorize its construction.

1920
Congress passes Kinkaid Act authorizing Secretary of the Interior to investigate problems of the Imperial Valley.

1922
Fall-Davis report entitled "Problems of Imperial Valley and Vicinity", prepared under the Kinkaid Act and submitted to Congress February 28th, recommends construction of the All-American Canal and a high dam on the Colorado River at or near Boulder Canyon. Representatives of the seven Colorado River Basin States sign the Colorado River Compact in Santa Fe, New Mexico, November 24th. First of the Swing-Johnson bills to authorize a high dam and canal is introduced in Congress.

1924
Weymouth report expands Fall-Davis report and further recommends Boulder Canyon project construction

1928
Colorado River Board of California reports favorably on feasibility of project. Boulder Canyon Project Act, introduced by Senator Johnson and Representative Swing, passes the Senate December 14th, the House December 18th, and is signed by President Calvin Coolidge, December 21st.

1929
Six of the seven Basin States approve Colorado River Compact. Boulder Canyon Project Act declared effective June 25th.

1930
Contracts for the sale of electrical energy to cover dam and power plant financing are completed.

1931
Bureau of Reclamation opens bids for the construction of Hoover Dam and Power Plant March 4, awards contract to Six Companies, March 11th, and gives contractor notice to proceed April 20th.

1932
River is diverted around the dam site, November 14th. Repayment contract for the construction of the All-American Canal is completed with Imperial Irrigation District.

1933
First concrete is placed June 6th.

1934
All-American Canal construction begins in August. Repayment contract between the United States and the Coachella Valley Water District covering cost of Coachella Main Canal executed October 15th.

1935
Dam starts impounding water in Lake Mead February 1st. Last concrete is placed in dam May 29th. President Franklin D. Roosevelt dedicates dam September 30th.

1936
First generator, N-2, goes into full operation October 26th. Second generator, N-4, goes into operations November 14th. Third generator, N-1, starts production December 28th.

1937
Generators N-3 and A-8 begin operation March 22 and August 16.

1938
Lake Mead storage reaches 24 million acre-feet, and lake extends 110 miles upstream. Generators N-5 and N-6 begin operation June 26 and August 31.

1939
Storage in Lake Mead reaches 25 million acre-feet, more than 8 trillion gallons. Generators A-7 and A-6 begin operations June 19 and September 12th, respectively. With an installed capacity of 704,800 kilowatts, Hoover Powerplant is the largest hydroelectric facility in the world- a distinction held until surpassed by Grand Coulee Dam in 1949.

1940
Power generation for the year totals 3 billion kilowatt-hours. All-American Canal placed in operation. Metropolitan Water District of Southern California successfully tests its Colorado River Aqueduct.

1941
Lake Mead elevation reaches 1220.45 feet above sea level July 30; lake is 580 feet deep, 120 miles long. Spillways are tested August 6th, the first time they have ever been used. Generator A-1 placed in service October 9th. Dam closes to Public at 5:30 p.m. December 7th, and traffic moves over the dam under convoy for duration of World War II.

1947
80th Congress passes legislation officially designating the Boulder Canyon Project's key structure "Hoover Dam" in honor of President Herbert Hoover.

1961
The power installation at Hoover Dam is complete when the final generating unit, N-8, goes on line December 1st. The installed generating capacity of Hoover Powerplant, including station service units, reaches 1,334,800 kilowatts.

1985
Hoover Dam celebrates 50th anniversary. Majority of the cost of the Boulder Canyon project has now been repaid to the Federal Treasury.

Last Reviewed: 9/10/2004