Colorado River Basin Water Management Evaluating and Adjusting to Hydroclimatic Variability (2007) / Chapter Skim
Currently Skimming:
2 Historical and Contemporary Aspects of Colorado River Development
2 Historical and Contemporary Aspects of Colorado River Development
Pages 26-72
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From page 26... ...
After crossing the Utah-Arizona border and passing Lees Ferry, the river flows westward through Grand Canyon National Park. A further 160 miles downstream -- after receiving flows from the Virgin River that drains southwestern Utah and parts of southern Nevada -- the Colorado reaches Boulder and Black canyons (which rim much of Lake Mead)
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From page 27... ...
The 1922 Colorado River Compact divided the river between the upper and lower basins and reserved unused water for future development in the four upper basin states. Beginning in 1922, California led the fight for the construction of a multipurpose dam on the lower Colorado (decades later they found that the price for having Hoover Dam constructed was a federal apportionment of the river among the three lower basin states)
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From page 28... ...
These include the accommodation of Indian claims, rapid population growth (especially in Arizona and in southern Nevada) , the need to control downstream salinity caused by irrigation runoff, disturbances to the Grand Canyon ecosystem caused by the operation of Glen Canyon Dam, and interests in restoring a remnant of the Colorado River Delta in Mexico.
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From page 29... ...
For purposes of this report, discussions of contemporary water management and scientific issues related to the Colorado River basin date back to the 19th-century origins of Anglo-American irrigated agriculture, and to the growth of urban water demand initiated by Los Angeles in the early 20th century. Well before this period, there was an extensive prehistory of water use in the basin, which is chronicled in a substantial body of archaeological and ethnohistorical research (see Brooks, 1974; Dart, 1989; Fish and Fish, 1994; Meyer, 1984)
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From page 30... ...
. The period from the mid-1860s to 1920 witnessed the diffusion of many new irrigation systems throughout the Colorado River basin.
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From page 31... ...
history. Glen Canyon Dam represents one of the last large western water storage projects, and no comparable water project has been built since in the Colorado River basin.
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From page 32... ...
are the 1922 Colorado River Compact, the 1928 Boulder Canyon Project Act, 1944 and 1973 international agreements with Mexico, the 1948 Upper Colorado River Basin Compact, the 1956 Colorado River Storage Project (CRSP) Act, the landmark Supreme Court decision (1963)
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From page 33... ...
were actively pro moting federal construction of Boulder Dam. This, in turn, raised concerns among other Colorado basin states that feared completion of the dam would allow California to divert a large portion, perhaps most, of the river's flow.
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From page 34... ...
, a politically driven agreement between the upper basin and lower basin states di viding rights to Colorado River flows (Billington and Jackson, 2006; Brigham, 1998; Hundley, 1975, 1992; Kleinsorge, 1941; Moeller, 1971)
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From page 35... ...
. By 1937 hydroelectric power from the dam was being transmitted to Southern California, and by 1940 power was used to pump water through the Metropolitan Water District of Southern California's Colorado River Aqueduct, a major water conduit serving domestic and industrial water supply needs in Los Angeles and surrounding cities (Bissell, 1939; Kleinsorge, 1941; Stevens, 1988)
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From page 36... ...
The dam is located 15 miles downstream from the Arizona-Utah border and 11 miles upstream from Lees Ferry. With a reservoir comparable in size to Lake Mead, storage provided by Lake Powell helps ensure that the upper basin states meet their water delivery obligations to the lower basin.
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From page 37... ...
The Colorado River Compact (1922) Signed in 1922 at Bishop's Lodge near Santa Fe, the Colorado River Compact is a cornerstone of the Law of the River.
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From page 38... ...
. As negotiated in 1922, the Compact apportions to both the upper basin and lower basin states the "exclusive beneficial consumptive use" of 7.5 million acre-feet annually.3 To accommodate year-to-year variations in river flow, the Compact provides that the upper basin states will not deplete the flow at Lees Ferry by more than 75 million acre-feet for any consecutive 10-year period (Ingram et al., 1991)
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From page 39... ...
and with California water agencies for that state's shares, plus additional available unused water. The upper basin states did not conclude any agreement among themselves affirming the allocations stipulated in the Boulder Canyon Project Act.
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From page 40... ...
Despite the language of guaranteed deliveries, the treaty contains provisions for relief in extreme circumstances, with guaranteed delivery of 1.5 million acre-feet per year subject to reduction in the event of shortages or drought upstream in the U.S. portion of the basin.4 It does not provide specifically for water of a given quality, but this did not constitute a significant issue on the Colorado River until many years later (see the discussion later in this section on a 1973 Minute between Mexico and the United States that addresses the quality of water delivered at the Mexico-U.S.
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From page 41... ...
. The Upper Colorado River Commission, established by the Upper Colorado River Basin Compact, determines the sufficiency of supply within the upper basin to meet the delivery obligation at Lees Ferry and then determines the amount of any curtailment in the upper basin that is required to meet this obligation.
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From page 42... ...
) and, largely for that reason, was the only state that refused to ratify the Compact in the 1920s.6 The Court further concluded that the Boulder Canyon Project Act reflected a decision by Congress that a "fair division" of the first 7.5 million acre-feet of the Colorado's mainstream waters "would give 4,400,000 acre-feet to California, 2,800,000 to Arizona, and 300,000 to Nevada," and that "Arizona and California would each get one-half of any surplus." Moreover, the Court went on to hold that allocation of the water in these shares did not depend on the lower basin states agreeing to them in a compact because "Congress gave the Secretary of the Interior adequate authority to accomplish the division." It did so "by giving the Secretary power to make contracts for the delivery of water and by providing that no person could have water without a contract." Through these contracts the Secretary could not only implement allocations among the lower basin states, but could also decide which users within each state would get water.
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From page 43... ...
. All this vast, interlocking ma chinery -- a dozen major works delivering water according to con gressionally fixed priorities for home, agricultural and industrial uses to people spread over thousands of square miles -- could func tion efficiently only under unitary management, able to formulate and supervise a coordinated plan that could take account of the di verse, often conflicting interests of the people and communities of the Lower basin States.
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From page 44... ...
Supreme Court found that in the Boulder Canyon Project Act Congress had given Arizona the right to withdraw 2.8 million acre-feet of flow annually from the mainstem of the Colorado River as part of a comprehensive scheme to apportion
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From page 45... ...
Signed into law by President Johnson in 1968 as part of the Colorado River Basin Project Act, the CAP and its Granite Reef Aqueduct took decades to construct. When completed in 1992, the CAP was capable of delivering 1.5 million acre-feet of water per year -- over half of Arizona's allocation as stipulated by the Boulder Canyon Project Act and affirmed by the U.S.
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From page 46... ...
Because many soils in the Colorado River basin have large amounts of naturally occurring salts, return flows from irrigated agri culture have also contributed to increased salinity levels. For exam ple, in the 1980s return flows from Colorado's Grand Valley added an estimated 580,000 tons of salt each year to the Colorado River (Mar ston, 1987)
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From page 47... ...
. In 1974 Congress passed the Colorado River Basin Salinity Control Act, which authorized construction, operation, and maintenance of works in the Colorado River basin to control the salinity of water delivered to users in the United States and Mexico.
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From page 48... ...
In the early 1980s the Bureau of Reclamation sought to upgrade the hydroelectric power generators at Glen Canyon Dam and adjust operations to increase the dam's peak generating capacity. These changes could have had significant impacts on river flows, but it was not entirely clear from a legal perspective that an EIS would be necessary.
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From page 49... ...
Two good examples of efforts in the Colorado River basin to balance shifting interests among a broad group of stakeholders are reflected in the Grand Can
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From page 50... ...
102-575) calls for the Secretary of the Interior to operate Glen Canyon Dam in accordance with the Law of the River and "in such a manner as to protect, mitigate adverse impact to, and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established, including, but not limited to natural and cultural resources and visitor use." The act calls for the Secretary of the Interior to define operating criteria for Glen Canyon Dam in consultation with the Bureau of Reclamation, the Fish and Wildlife Service, the National Park Service, the Department of Energy, basin states, Indian tribes, and members of "the general public" that include environmental and recreational interests.
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From page 51... ...
From 1995 to 2005, population of the seven Colorado River basin states grew by nearly 11 million, an increase of roughly 25 percent (Griles, 2004) .9 These high percentage rates of population growth certainly stand out, but they should be considered along with absolute numbers of population growth.
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From page 52... ...
. Today's population levels and growth rates, intensifying competition for limited water supplies, and nontraditional water uses such as recreation and instream flows suggest that the relationships between population and urban water supplies soon will have to be confronted more seriously than in the past.
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From page 53... ...
FIGURE 2-6 Percent change in U.S. population, 1990-2000.
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From page 54... ...
. Population growth in the West is contributing to increasing water demands.
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From page 55... ...
As a scientific field, however, regional water demand forecasting lags behind much research on hydroclimatic and other water resources issues. Increasing population growth rates and water demands in the 1990s and early 2000s have prompted many water users and managers to consider nontraditional means to extend water supplies.
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From page 56... ...
. As in many regions of the United States, Colorado River basin groundwater resources have been heavily utilized to satisfy agricultural, municipal, and industrial water demands.
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From page 57... ...
. Passage of the Groundwater Management Act saw the Adequate Water Supply Program replaced by the Assured Water Sup ply Program (Davis, 2006)
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From page 58... ...
58 TABLE 2-2 Water Demands in Arizona A-F Change % Change Category Water Demand (acre-feet) 1990-2040 1990-2040 1990 2015 2040 1,332,000 1,922,000 2,605,000 1,273,000 96 Municipal and industrial 5,339,000 5,220,000 5,037,000 - 302,000 -6 Agriculture 6,671,000 7,142,000 7,642,000 971,000 15 STATE TOTAL SOURCE: http://geochange.er.usgs.gov/sw/impacts/society/water_demand/.
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From page 59... ...
Many creative water transfer programs, involving legally defined water banks and underground water storage programs, have been developed to help effect these transfers, but the amount of agricultural water is finite and such programs thus are necessarily limited in their ability to satisfy ever-increasing demands over the long term. Certain basin states also have consistently opposed leasing, trading, or selling of water beyond state boundaries, although many complex, recent agreements are designed to allow flexibility while protecting allocations.
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From page 60... ...
If California met this and other benchmarks, it would continue to have ac cess to more than its share of Colorado River water during a transition period, making possible a so-called "soft landing" as it gradually re duced its use to the allocation of 4.4 million acre-feet as specified in the 1928 Boulder Canyon Project Act. However, if it missed a benchmark it would immediately lose access to all water above that amount, resulting in a "hard landing." The latter outcome followed from the failure of the rural and urban agencies to adopt a QSA by the end of 2002.
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From page 61... ...
Early 21st Century Drought A severe, multiyear drought across much of the western and southwestern United States in the early 21st century had substantial impacts on Colorado River basin water supplies. Figure 2-7, for example, illustrates changing patterns of precipitation and the worsening drought across the region from 2000 to 2006.
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From page 62... ...
62 September 25, 2001 September 26, 2000 September 24, 2002 September 30, 2003 September 28, 2004 September 27, 2005 September 26, 2006 FIGURE 2-7 Western U.S. drought conditions, 2000-2006.
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From page 63... ...
The Colorado River basin drought of the early 21st century saw well below normal inflows into Lake Powell for the 5 year period 2000-2004. It should be noted, however, that 1999 and 2005 both had only slightly above-normal inflows, and one or two years of slightly above normal inflows do not end a drought of such magnitude.
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From page 64... ...
. Precipitation across the Colorado River basin was closer to average conditions in 2005, but in 2006 drier conditions returned and were exacerbated by above-normal temperatures; July 2006, for example, was the second-warmest-ever month of July in the continental United States (http://www.noaanews.noaa.gov/stories2006/s2677.
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From page 65... ...
FIGURE 2-9 Glen Canyon Dam and Lake Powell, August 2004. Note the residual ring around the top of the lake caused by declining water levels.
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From page 66... ...
Coping with Drought and Increasing Water Demands The early 21st century drought has been notable for its hydrologic and related impacts, such as forest fires in some areas of the Colorado River basin. The drought, along with increasing population growth and water demands, stimulated a variety of responses.
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From page 67... ...
FIGURE 2-10 Potential water supply crisis areas in the western United States. SOURCE: http://www.doi.gov/water2025/supply.html.
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From page 68... ...
. An important development that grew out of drought conditions in the early 2000s was a letter of agreement signed by representatives of all seven Colorado River basin states (see Appendix A)
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From page 69... ...
Dam and ended with the construction of Glen Canyon Dam. A third phase of Colorado River water development extended from 1965 until the mid-1980s.
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From page 70... ...
Even during the drought of the early 2000s and lowered water storage in Lake Powell, Glen Canyon Dam was delivering flows above the upper basin's Colorado River Compact commitment. There is no imminent prospect that this delivery obligation will not be met, and any change in the Colorado River Compact would require the resolution of numerous complex legal issues that could require many years or even decades to resolve.
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From page 71... ...
If changes in climate rendered the Law of the River inadequate to deal with resulting shortages, the Colorado River basin states could conceivably seek to amend the Compact and the United States and Mexico could conceivably seek an amendment of their 1944 treaty. Water releases from Glen Canyon Dam are a key issue at the hydrology-climatepopulation growth nexus in the Colorado River basin and bear close watching in the years ahead.
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From page 72... ...
Steadily rising population and urban water demands in the Colorado River region will inevitably result in increasingly costly, controversial, and unavoidable trade-off choices to be made by water managers, politicians, and their constituents. These increasing demands are also impeding the region's ability to cope with droughts and water shortages.
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