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1907
MAY 13, 1907
Colorado River History
Doctrine of Equitable Apportionment Adopted

U.S. Supreme Court adopts the Doctrine of Equitable Apportionment of benefits for rivers flowing between states.  Kansas v. Colorado, 206 U.S. 46.  The equitable apportionment doctrine is based on the “cardinal rule” of “equality of right” among states.  “Each state stands on the same level with all the rest.”  The Court later explains that “equality of right” refers “not to an equal division of the water, but to the equal level or plane on which all the states stand, in point or power and right, under our constitutional system.”  Wyoming v. Colorado, 259 U.S. 419, 465 (1922).

1919
1919
Colorado River History
League of the Southwest Organized

Seven basin states organize League of the Southwest in Salt Lake City, Utah, to promote Colorado River development.

1921
1921
Colorado River History
Equitable Division and Apportionment Authorized

Congress authorizes the seven basin states to negotiate and enter into an interstate compact providing for the equitable division and apportionment of the Colorado River.

1922
January 26, 1922
Colorado River History
Colorado River Commission Organized

The Colorado River Commission is organized in Washington, D.C.

1922
Colorado River History
Fall-Davis Report Submitted

The Fall-Davis Report submitted to Congress recommends construction of the All-American Canal in California and a dam at Boulder Canyon in Nevada.

June 5, 1922
Colorado River History
Wyoming V. Colorado

U.S. Supreme Court rules that the doctrine of prior appropriation can be applied between states where each of the states adheres to that doctrine.  Wyoming v. Colorado, 259 U.S. 419.

November 24, 1922
Colorado River History
Colorado River Compact Signed

• First agreement to legally connect the states that share the Colorado River water supply

• Designated the Upper and Lower Colorado River Basins, allocating 7.5 MAF/year to each

• Arizona refused to ratify the Compact until 1944

1923
January 26, 1922
Colorado River History
Colorado River Compact Ratified

All states, except Arizona, ratify the Colorado River Compact.

1928
December 21, 1928
Colorado River History
Boulder Canyon Project Act of 1928

• Authorized construction of Hoover Dam

• Apportioned Colorado River water among the Lower Basin states: 2.8 MAF/year to Arizona; 4.4 MAF to California; 300,000 acre-feet to Nevada

1929
1929
Colorado River History
California Limitation Act Enacted

California enacts the California Limitation Act, agreeing to limit its use of Colorado River water to 4.4 million acre feet (MAF) per year.

June 25, 1929
Colorado River History
Boulder Canyon Project Act in Effect

President Hoover declares the Boulder Canyon Project Act to be in effect.

1930
October 13, 1930
Colorado River History
Suit filed by Arizona

Arizona files suit in the Supreme Court against the Secretary of the Interior and the other six basin states seeking to block implementation of the Boulder Canyon Project Act.

November 5, 1930
Colorado River History
California asked to recommend apportionment for California users

Secretary of the Interior asks California to recommend an apportionment of its share of the Colorado River among water users in that state.

1931
May 18, 1931
Colorado River History
Arizona’s action dismissed without prejudice

U.S. Supreme Court dismisses Arizona’s action without prejudice, holding that the Boulder Canyon Project Act is a valid exercise of congressional authority and does not purport to abridge any of Arizona’s rights. Arizona v. California (I), 283 U.S. 423.

August 18, 1931
Colorado River History
Relative priorities established by California Seven Party Agreement

California Seven Party Agreement among Palo Verde Irrigation District, Imperial Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, City of San Diego and County of San Diego establishes their relative priorities to Colorado River water.

September 28, 1931
Colorado River History
Amended contract entered into by MWD

Metropolitan Water District of Southern California enters into an amended contract with the Secretary of the Interior for delivery of Colorado River water in accordance with the California Seven Party Agreement.

1932
December 1, 1932
Colorado River History
Contract entered into by Imperial Irrigation District

Imperial Irrigation District enters into a contract with the Secretary of the Interior for delivery of Colorado River water in accordance with the California Seven Party Agreement. Contract also provides that the United States will construct Imperial Dam and the All-American Canal.

1933
February 7, 1933
Colorado River History
Contract entered into by Palo Verde Irrigation District

Palo Verde Irrigation District enters into a contract with the Secretary of the Interior for delivery of Colorado River water in accordance with the California Seven Party Agreement.

February 15, 1933
Colorado River History
Contract entered into by City of San Diego

City of San Diego enters into a contract with the Secretary of the Interior for delivery of Colorado River water in accordance with the California Seven Party Agreement.

1934
February 14, 1934
Colorado River History
Arizona seeks to file a complaint in U.S. Supreme Court

Arizona seeks to file a complaint in the U.S. Supreme Court to perpetuate testimony for a future action arising out of the Boulder Canyon Project Act to be brought against California and others.

May 21, 1934
Colorado River History
Arizona’s motion denied by Supreme Court

The U.S. Supreme Court denies Arizona’s motion.  Arizona v. California (II), 292 U.S. 341.

October 15, 1934
Colorado River History
Contract entered into by Coachella Valley County Water District

Coachella Valley County Water District enters into a contract with the Secretary of the Interior for delivery of Colorado River water in accordance with the California Seven Party Agreement.

1935
October 1935
Colorado River History
Arizona petitioned to file suit against California

Arizona petitions to file suit against California in the U.S. Supreme Court, seeking to quiet title to Arizona’s equitable share of the Colorado River and to limit California’s equitable share to no more than 4.4 MAF. Arizona also asks for a decree that any other state’s use of Arizona’s equitable share of the Colorado River shall not constitute a prior appropriation or create any right superior to Arizona’s.

1936
May 25, 1936
Colorado River History
Supreme Court again denies Arizona’s motion

The U.S. Supreme Court again denies Arizona’s motion.

1938
July 1, 1938
Colorado River History
Parker Dam completed

Parker Dam is completed.

1938
Colorado River History
Committee of Fourteen organized

The seven basin states organize the Committee of Fourteen, comprised of two representatives from each state, to address Colorado River issues.

1939
January 7, 1939
Colorado River History
MWD diversions begin

Metropolitan Water District of Southern California begins diverting water through the Colorado River Aqueduct.

1944
January 3, 1944
Colorado River History
Nevada enters into a contract

Nevada enters into a contract with the Secretary of the Interior for delivery of 300,000 acre-feet of Colorado River water.

February 3, 1944
Colorado River History
1944 U.S.-Mexico Water Treaty

• Apportioned 1.5 MAF/year of Colorado River to Mexico during normal years and specified that Mexico would share proportionately in times of surplus and in reductions due to “extraordinary drought”

• Established the binational International Boundary and Water Commission to implement the Treaty

1944
Colorado River History
Arizona ratifies the Colorado River Compact

Arizona ratifies the Colorado River Compact.

1945
June 11, 1945
Colorado River History
Supreme Court retreats from Wyoming v. Colorado ruling

The U.S. Supreme Court retreats somewhat from its ruling in Wyoming v. Colorado, holding that “strict adherence to the priority rule” when equitably apportioning the flow of a river among prior appropriation states “may not be possible.” While priority remains the “guiding principle,” the Court identifies a number of additional factors that may be taken into account. “For example, the economy of a region may have been established on the basis of junior appropriations. So far as possible those established uses should be protected though strict application of the priority rule might jeopardize them.”  Nebraska v. Wyoming, 325 U.S. 589, 618.

1947
1947
Colorado River History
Arizona seeks legislation to authorize the Central Arizona Project

Arizona seeks legislation authorizing Central Arizona Project (CAP). California opposes.

1948
1948
Colorado River History
Upper Colorado River Basin Compact signed

The Upper Colorado River Basin Compact is signed by Arizona, Colorado, New Mexico, Utah and Wyoming.

1950
February 21, 1950
Colorado River History
U.S. Senate passes CAP legislation

U.S. Senate passes CAP legislation.

December 15, 1950
Colorado River History
CAP legislation dies in U.S. House committee

CAP legislation dies in U.S. House committee.

1951
April 18, 1951
Colorado River History
CAP legislation indefinitely postponed

U.S. House Committee on Interior and Insular Affairs indefinitely postpones action on CAP legislation “until such time as the use of the water in the Lower Colorado River Basin is either adjudicated, or a binding, mutual agreement as to the use of the water is reached by the states of the Lower Colorado River Basin.” (The Colorado River Board of California later boasted that it had been “instrumental” in achieving this result.)

June 5, 1951
Colorado River History
U.S. Senate passes CAP legislation for the second time

U.S. Senate passes CAP legislation for the second time.

1952
August 13, 1952
Colorado River History
Arizona files suit against California

Arizona files suit against California in the U.S. Supreme Court to establish its right to Colorado River water.

1954
June 1, 1954
Colorado River History
U.S. Supreme Court grants Nevada’s motion to intervene

U.S. Supreme Court grants Nevada’s motion to intervene in Arizona v. California (IV).

1955
December 12, 1955
Colorado River History
U.S. Supreme Court denies California’s motion

U.S. Supreme Court denies California’s motion to join the four Upper Colorado River Basin states in Arizona v. California (IV), but joins New Mexico and Utah as Lower Colorado River Basin states.

1963
1963
Colorado River History
Arizona v. California decision

U.S. Supreme Court decision in Arizona v. California.

1963
Colorado River History
Glen Canyon Dam completed

Reclamation completes Glen Canyon Dam (Lake Powell).

June 1963
Colorado River History
California opposes authorization of Central Arizona Project

In reaction to the U.S. Supreme Court’s opinion, California immediately announces that it will oppose authorization of CAP.

1964
March 9, 1964
Colorado River History
U.S. Supreme Court Decree: Arizona v. California

• After a decade of deliberation, the U.S. Supreme Court delivered its opinion in favor of Arizona, upholding its designated 2.8 MAF/year share of mainstream Colorado River water

• Effectively established the U.S. Secretary of the Interior as the Lower Basin “water master”

1965
1965
Colorado River History
Western States Water Council established

Western governors establish the Western States Water Council to avoid interstate conflict by developing regional solutions to water problems.

August 20, 1965
Colorado River History
Basin states agree on four principles

Meeting in Washington, D.C., representatives of the seven basin states reach agreement on four general principles:

•The Lower Basin’s temporary use of unused Upper Basin water will not jeopardize Upper Basin rights.

•Importation of water from outside the Colorado River Basin is essential and pending legislation should authorize construction of works to import at least 2.5 MAF.

•Imported water should be available no later than 1980, although there appears to be sufficient water to meet all needs, including CAP, until the 1990s.

•Satisfaction of the Mexican treaty obligation should be a national obligation and the first priority for imported water.

1968
September 30, 1968
Colorado River History
Colorado River Basin Project Act
Colorado River Basin Project Act

• Authorized the Bureau of Reclamation to fund and construct the Central Arizona Project – learn more here

• Created a junior priority in the Lower Basin for CAP water and for any new Arizona contracts entered after 1968 in times when insufficient mainstem Colorado River water is available to deliver a total of 7.5 million acre-feet to Arizona, California and Nevada

• Directed the U.S. Secretary of the Interior to develop a plan for augmenting the Colorado River supply

• Declared the Mexican Treaty delivery obligation a “national obligation”

1970
1970
Colorado River History
Criteria for Coordinated Long-Range Operation of Colorado River Reservoirs adopted
1973
1973
Colorado River History
Minute 242 entered

U.S. and Mexico enter Minute 242 to the 1944 Treaty addressing salinity of water delivered to Mexico at Morelos Dam.

1974
1974
Colorado River History
Colorado River Basin Salinity Control Act passes

The Colorado River Basin Salinity Control Act authorizes salinity control projects above and below Imperial Dam, including the Yuma Desalination Plant.

1999
1999
Colorado River History
Secretary of the Interior adopts regulations

U.S. Secretary of the Interior adopts regulations for off-stream storage and release of unused apportionment enabling interstate water banking in the Lower Basin.

2001
2001
Colorado River History
Interim Surplus Guidelines adopted

U.S. Secretary of the Interior adopts Interim Surplus Guidelines establishing criteria for declaring surpluses in the Lower Basin states.

2003
January 1, 2003
Colorado River History
Interim surplus determinations suspended

Interim surplus determinations are suspended after California parties fail to complete a quantification settlement agreement by the December 31, 2002 deadline in the Interim Surplus Guidelines.

October 10, 2003
Colorado River History
Colorado River Water Delivery Agreement adopted

United States enters into Colorado River Water Delivery Agreement with Imperial Irrigation District, Coachella Valley Water District, Metropolitan Water District of Southern California and San Diego County Water Authority. The agreement memorialized the U.S. Secretary of the Interior’s commitment to deliver water to California contractors in accordance with the Quantification Settlement Agreement.

2003
Colorado River History
Quantification Settlement Agreement executed
The
Quantification Settlement Agreement executed memorializing U.S. commitment to deliver water to California.
2005
May 2, 2005
Colorado River History
Efforts to develop conjunctive management guidelines begin

The U.S. Secretary of the Interior announces her intent to develop guidelines for conjunctive management of Lakes Powell and Mead and shortage sharing in the Lower Basin by Dec. 31, 2007, and initiates a public process toward that end. The Basin States are encouraged to reach agreement.

2006
February 3, 2006
Colorado River History
Preliminary Proposal Regarding Colorado River Interim Operations submitted

Basin States submit a Preliminary Proposal Regarding Colorado River Interim Operations, including coordinated management of Lake Powell and Lake Mead and shortage guidelines for the lower basin.

2006
Colorado River History
U.S. Supreme Court enters Consolidated Decree

The U.S. Supreme Court enters its Consolidated Decree in Arizona v. California.

2007
February 28, 2007
Colorado River History
2007 Interim Guidelines

• Established a shortage framework for the Lower Basin

• Incentivized storage of water in Lake Mead through Intentionally Created Surplus (ICS)

Coordinated operations of Lake Powell and Lake Mead

• Expire in 2026

2012
2012
Colorado River History
Minute 319 entered

U.S. and Mexico enter Minute 319 to the 1944 Treaty establishing criteria to share in water surpluses and shortages.

2012
Colorado River History
Colorado River Basin Water Supply and Demand Study released
2014
2014
Colorado River History
Pulse flow released

Environmental pulse flow and base flow, allowed by Minute 319 to the 1944 Treaty, are released through the Colorado River channel in Mexico to start new vegetation for wildlife habitat.

2017
2017
Colorado River History
Minute 323

Minute 323 expanded collaboration and sharing of shortage risks and surplus opportunities between Mexico and the U.S. and provided for U.S. investment in water infrastructure and environmental projects in Mexico. It also established a work group to investigate binational desalination in the Sea of Cortez, as well as the binational water scarcity contingency plan.

2019
April 16, 2019
Colorado River History
Drought Continency Plan Authorization Act

Lower Basin highlights (learn more about Arizona’s implementation plan here):

   - Supplements the 2007 Interim Guidelines
   - Provides additional flexibility for the creation, storage and delivery of ICS
   - Created a “Tier Zero” at Lake Mead, requiring contributions to Lake Mead earlier, starting at elevation 1090’, and increased contributions at lower elevations
   - California agrees to make contributions to Lake Mead starting at elevation 1045’
   - Provided for the protection of Lake Mead elevation 1020’ – 500+ Plan

Upper Basin highlights:
   - Designed to minimize the risk of Lake Powell falling below elevation 3525’ and ensure compliance with the Colorado River Compact
   - Establish foundation for the storage of water in the Upper Basin as part of a demand management program that may be developed in the future

 

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This link is taking you away from the CAP website and provides information on an external site that is consistent with the intended purpose of the CAP website. CAP cannot attest to the accuracy of the information provided by this link or any other linked site. CAP is not responsible for the information or links provided by sponsors of the site or any products presented on the site. These links do not represent an endorsement by CAP or its directors or employees of site sponsors or products.

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This link is taking you away from the CAP website and provides information on an external site that is consistent with the intended purpose of the CAP website. CAP cannot attest to the accuracy of the information provided by this link or any other linked site. CAP is not responsible for the information or links provided by sponsors of the site or any products presented on the site. These links do not represent an endorsement by CAP or its directors or employees of site sponsors or products.