Editing Colorado River (section)

===Boulder Canyon Project===
[[Image:HooverDamConstruction.jpg|thumb|right|Hoover Dam under construction, 1934]]
[[Image:IMPERIAL_DAM_TAKES_LAST_OF_COLORADO_RIVER_WATER_FOR_THE_UNITED_STATES._IT_DIVERTS_WATER_INTO_ALL-AMERICAN_CANAL...._-_NARA_-_548847.jpg|thumb|right|The Imperial Dam (bottom right) diverts water into the All-American Canal (center) running towards Imperial Valley.]]
A large dam on the Colorado River had been envisioned since the 1920s. In 1928, Congress authorized the Reclamation Service (today's [[U.S. Bureau of Reclamation]], or USBR) to build the Boulder Canyon Project, whose key feature would be a dam on the Colorado in Black Canyon {{convert|30|mi|km}} southeast of [[Las Vegas, Nevada]]. On September 30, 1935, [[Hoover Dam]] was completed, forming [[Lake Mead]], capable of holding more than two years of the Colorado's flow. Lake Mead was, and still is, the largest artificial lake in the U.S. by storage capacity.<ref name="LakeMead"/><ref>{{cite web |url=http://www.usbr.gov/projects/Project.jsp?proj_Name=Boulder%20Canyon%20Project%20-%20Hoover%20Dam |title=Boulder Canyon Project – Hoover Dam |publisher=U.S. Bureau of Reclamation |date=February 1, 2012 |access-date=October 9, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121011123506/http://www.usbr.gov/projects/Project.jsp?proj_Name=Boulder%20Canyon%20Project%20-%20Hoover%20Dam |archive-date=October 11, 2012}}</ref> The construction of Hoover Dam stabilized the lower channel of the Colorado River, stored water for irrigation in times of drought, captured sediment and controlled floods. Hoover was the tallest dam in the world at the time of construction and also had the world's largest hydroelectric power plant.<ref>{{cite web |url=http://www.usbr.gov/lc/region/pao/brochures/faq.html |title=The Colorado River and Hoover Dam: Facts and Figures |publisher=U.S. Bureau of Reclamation |date=January 2012 |access-date=February 20, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120514124746/http://www.usbr.gov/lc/region/pao/brochures/faq.html |archive-date=May 14, 2012}}</ref>

The Boulder Canyon Project Act also authorized the [[All-American Canal]],<ref>{{cite web |url=https://www.archives.gov/milestone-documents/boulder-canyon-project-act |title=Boulder Canyon Project Act (1928) |publisher=National Archives |date=September 21, 2021 |access-date=May 18, 2022 |archive-date=May 18, 2022 |archive-url=https://web.archive.org/web/20220518173242/https://www.archives.gov/milestone-documents/boulder-canyon-project-act |url-status=live }}</ref> which was built as a permanent replacement for the Alamo Canal and follows a route entirely within the U.S. on its way to the Imperial Valley. The canal's intake is located at [[Imperial Dam]], {{convert|20|mi|km}} above [[Yuma, Arizona]], which diverts the majority of the Colorado's flow with only a small portion continuing to Mexico. With a capacity of over {{convert|26000|cuft/s|m3/s}}, the All-American Canal is the largest irrigation canal in the world.<ref>{{cite web |url=http://earthobservatory.nasa.gov/IOTD/view.php?id=37078 |title=All-American Canal, California–Mexico border |publisher=National Aeronautics and Space Administration |work=Earth Observatory |date=February 23, 2009 |access-date=February 20, 2012 |archive-date=August 19, 2021 |archive-url=https://web.archive.org/web/20210819071906/https://earthobservatory.nasa.gov/images/37078/all-american-canal |url-status=live }}</ref> Because the hot, sunny climate lends to a year-round growing season, the Imperial Valley has become one of the most productive farming regions in North America, providing much of the winter produce supply in the U.S.<ref name="ImperialEB">{{Cite encyclopedia |title=Imperial Valley |encyclopedia=Encyclopædia Britannica |year=1995}}</ref> The Imperial Irrigation District supplies water to {{convert|520000|acre|ha}} south of the Salton Sea.<ref>{{cite web |url=https://www.iid.com/water/about-iid-water |title=About IID Water |publisher=Imperial Irrigation District |date= |access-date=May 18, 2022 |archive-date=May 6, 2022 |archive-url=https://web.archive.org/web/20220506235625/https://www.iid.com/water/about-iid-water |url-status=live }}</ref> The [[Coachella Canal]], which branches northward from the All-American Canal, irrigates another {{convert|78000|acre|ha}} in the [[Coachella Valley]].<ref>{{cite web |url=https://www.usbr.gov/projects/index.php?id=492 |title=CRBSCP - Coachella Canal Unit - Title I |publisher=U.S. Bureau of Reclamation |date= |access-date=May 18, 2022 |archive-date=May 19, 2022 |archive-url=https://web.archive.org/web/20220519013457/https://www.usbr.gov/projects/index.php?id=492 |url-status=live }}</ref>

[[Parker Dam]] was initially built as the diversion point for the [[Colorado River Aqueduct]], planned by the [[Metropolitan Water District of Southern California]] to supply water to [[Los Angeles, California|Los Angeles]].<ref>{{cite web |url=http://www.usbr.gov/projects/Facility.jsp?fac_Name=Parker+Dam&groupName=General |title=Parker Dam |publisher=U.S. Bureau of Reclamation |work=Parker-Davis Project |date=June 29, 2009 |access-date=February 20, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120927195113/http://www.usbr.gov/projects/Facility.jsp?fac_Name=Parker+Dam&groupName=General |archive-date=September 27, 2012}}</ref> The construction of the dam was opposed by Arizona, which feared that California would take too much water from the Colorado; at one point, Arizona sent members of its National Guard to stop work on the dam. Ultimately, a compromise was reached, with Arizona dropping its objections in exchange for the USBR constructing the Gila Project, which irrigates {{convert|110000|acre|km2}} on the Arizona side of the river.<ref>{{cite web |url=http://www.usbr.gov/projects//ImageServer?imgName=Doc_1305042259136.pdf |title=Gila Project |author=Marie Bell, Tina |publisher=U.S. Bureau of Reclamation |year=1997 |access-date=February 28, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120224024443/http://www.usbr.gov/projects//ImageServer?imgName=Doc_1305042259136.pdf |archive-date=February 24, 2012}}</ref> By 1941, the {{convert|241|mi|km|adj=on}} long Colorado River Aqueduct was completed, delivering {{convert|1.2|e6acre.ft|km3}} of water west to Southern California. The aqueduct enabled the continued growth of Los Angeles and its suburbs, and provides water to about 10&nbsp;million people today.<ref>{{cite web |url=http://wsoweb.ladwp.com/Aqueduct/historyoflaa/coloradoriver.htm |title=The Colorado River: A Regional Solution |publisher=Los Angeles Department of Water and Power |access-date=February 28, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120304000641/http://wsoweb.ladwp.com/Aqueduct/historyoflaa/coloradoriver.htm |archive-date=March 4, 2012}}</ref> The [[San Diego Aqueduct]], which branches off from the Colorado River Aqueduct in [[Riverside County, California]], opened in stages between 1954 and 1971 and provides water to another 3&nbsp;million people in the [[San Diego]] metro area.<ref>{{cite web |url=http://www.usbr.gov/projects/Project.jsp?proj_Name=San+Diego+Project |title=San Diego Project |publisher=U.S. Bureau of Reclamation |date=January 11, 2012 |access-date=March 16, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120316220454/http://www.usbr.gov/projects/Project.jsp?proj_Name=San+Diego+Project |archive-date=March 16, 2012}}</ref>

The Las Vegas Valley of Nevada experienced rapid growth after Hoover Dam, and by 1937 Las Vegas had tapped a pipeline into Lake Mead. Nevada officials, believing that groundwater resources in the southern part of the state were sufficient for future growth, were more concerned with securing a large amount of the dam's power supply than water from the Colorado; thus they settled for the smallest water allocation of all the states in the Colorado River Compact.<ref>{{cite web |url=http://www.crwua.org/colorado-river/member-states/nevada |title=Nevada |publisher=Colorado River Water Users Association |access-date=November 2, 2013 |archive-url=https://web.archive.org/web/20131104165703/http://www.crwua.org/colorado-river/member-states/nevada |archive-date=November 4, 2013 |url-status=dead}}</ref> In 2018, due to declining water levels in Lake Mead, a second pipeline was completed with a lower intake elevation.