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Impact on the Colorado River Basin en c! Southwest Water Supply 8 JOHN A. DRACUP University of California, Los AngeZes INTRODUCTION When the Spaniard Francisco de Ulloa first discovered the mouth of the Colorado River in 1537, a fierce tidal bore and river flow made him fearful for his ship (see Watkins et al., 19691: We perceived the sea to run with so great a rage into the land that it was a thing much to be marvelled at; and with a fury it returned back again with the ebb . . . and some Fought . . . Hat some great river might be the cause thereof. De Ulloa sailed up the river delta as far as the conflu- ence with the Gila. Today, Colorado River diversions have caused the river to disappear before reaching the Sea of Cortez. Therefore, such a journey is no longer a possibility. Considered here are the current and projected scenarios of one of the major river basins in the United States the Colorado. Examined are the combined hydro- logic, legal, and demand constraints and how these con- straints are affected when accentuated by an additional adverse climatic future. 121 Thus, the problem to be considered in this paper is one of prediction, namely, the prediction of the effects of climatic variability and changes on future water supplies. The Colorado River Basin is presented as a case study. It is hoped that the estimates and predictions concluded here will strike the mark closer than those of I. C. Ives, an early explorer of the Southwest, who wrote: Ours has been the first, and will doubtless be Be last party of whites to visit this profitless locality. It seems intended by nature that the Colorado River, along the greater portion of its lonely and majestic way, shall be forever unvisited and undisturbed. The National Park Service reports that the forty- millionth visitor will enter Grand Canyon National Park sometime during the 1970's (Dolan et al., 1974~. Thus, we are confronted with an environmental impact of man on the river and an economic impact of the river on man. The water resources of the southwest United States are dominated by the Colorado River Basin. This 243,000- square-mile basin can be thought to be analogous to a cat who has given birth to too many kittens there just isn't enough "milk" to go around. With the exception of the

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Impact on the Colorado River Basin and Southwest Water Supply deserts of the Great Basin, the Colorado River Basin has the greatest water deficiency (average precipitation less potential evapotranspiration) of any basin in the coter- minous United States (Piper, 1965~. Yet, more water is exported from the Colorado River Basin than from any other river basin in the United States (Committee on Water, 1968~. Any consideration of a negative climatic environment on the southwestern United States and particularly on the Colorado River Basin would immediately appear even to the most casual observer as a stress on a system already under considerable stress. It brings to mind A. A. Milne's lines from Now We Are Six: At times like these the bravest knight May find his armour much too tight. Looking at the Colorado River system we find a highly variable and continuously modified hydrologic flow re- gime. The river is situated in a region whose need for water when projected 25 years into the future demon- strates that man's efforts of a half century ago to apportion the limited supply to the expected needs were in- adequate to compensate for the vast difference between potential need and potential available supply. GEOGRAPHIC DESCRIPTION The 243,000-square-mile basin drainage involves areas in seven states and was arbitrarily divided by the Colorado River Compact at Lee Ferry, Arizona, into the Upper Colorado Basin and the Lower Colorado Basin for pur- poses of interstate administration. The Upper Basin drainage includes those areas of Arizona, Colorado, New Mexico, Wyoming, and Utah that drain into the Colorado River above Lee Ferry, Arizona. It is bounded on the east and north by mountains forming the Continental Divide, and on the south it opens to the Lower Colorado region at Lee Ferry in northern Arizona. The Colorado River rises in north-central Colorado in mountains more than 14,000 feet high. Then it travels 640 river miles through the Upper Basin to Lee Ferry at an elevation of 3000 feet. The major tributary is the Green River, which begins in Wyoming and discharges into the Colorado River in southeastern Utah, 730 miles from its origin and 220 river miles upstream from Lee Ferry. The Lower Basin drainage includes most of Arizona, parts of southeastern Nevada, southeastern Utah, south- eastern California, and western New Mexico (Figure 8.1~. A wide range of climate occurs because of differences in altitude, latitude, and topographic features. In the north, summers are short and warm, winters are long and cold. In the southern part, the summers are longer and the winters are moderate at low altitudes, but colder tempera- tures occur in the mountains. From October to May, the precipitable moisture is transported by maritime air masses from the Pacific 123 Ocean. During the summer months, most of the precipita- tion is brought from the Gulf of Mexico. A winter snow- pack accumulates in the higher mountain regions and provides most of the surface runoff during the spring melting season. The evaporation rates vary from approximately 30 inches in the northern, higher areas to approximately 86 inches in the southern part of the basin. CURRENT LEGAL FRAMEWORK The laws governing the Colorado River have been pre- sented in detail by Meyers (1966) and Weatherford and .Jacoby (1975~. Only a brief summary of the major treaties, laws, and compacts will be presented here. The allocation of the Colorado River is based on the concept of beneficial consumptive use. The allocation system operates at four levels: international, interre- gional, interstate, and intrastate (Weatherford and Jacoby, 1975~. The international allocation was accomplished by the Mexican Water Treaty of 1944. Mexico was guaranteed an annual amount of 1.5 million acre-feet (maf) except in times of extreme shortage. However, this treaty contained no provision for water quality. Thus, joint agreements in 1965 and 1973 called for a temporary agricultural drain- age water bypass and eventually a desalting plant to improve the quality of water crossing the border. The interregional allocation was achieved when Con- gress approved the Colorado River Compact, which be- came effective in tune 1929. Sectional rivalry has caused the states included in the drainage basin to agree to an equal apportionment of the Colorado River waters be- tween the states of the Upper Basin (composed of the states of Colorado, New Mexico, Utah, and Wyoming and a portion of Arizona) and the states of the Lower Basin (composed of the states of Arizona, California, and Nevada) [Colorado River Compact, 1922, Article III(b) and Article III(d)~. Traditionally, the fertile lowland valleys, i.e., the states of the Lower Division (Arizona, California, and Nevada), develop more rapidly than the mountainous headwater regions called the "areas of origin," i.e., the states of the Upper Division (Colorado, New Mexico, Utah, and Wyoming). Thus the Upper Basin states insisted that an equitable apportionment of the river be made prior to the expenditure of large federal sums of money, which might result in a modification of equities adverse to the Upper Basin states. This is in essence what was achieved in the 1922 Colorado River Compact. The intent of this landmark document was to give each basin the perpetual right to the "exclusive beneficial use of 7,500,000 acre-feet of water per annum...." However, the Lower Basin was assured that depletion in the Upper Basin would allow at least a 75 mat flow to the Lower Basin at Lee Ferry in each successive ten-year period. Thus, the Lower Basin received a guaranteed ten-year,

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124 not annual, minimum flow, and the Upper Basin assumed the burden of any deficiency caused by a hydrologic dry cycle. However, there are differing viewpoints concern- ing this allocation. For example, Saunders (1976) states: The intent of the Colorado River Compact is clearly expressed in Article III(a) to make an equal division of water between the Upper and Lower Basins. Substantial analysis of the remainder of the Compact indicates this clear intent. Paragraph III(d) is not an apportionment at all, but an attempt to implement paragraph III(a) on the basis of a mutual mistake of facts as to how much water was available for apportionment. This being the case, the actual shortage of the water which has been discovered since Me making of the Colorado River Compact must fall equally on the Upper and Lower Basins. The allocation of the 1.5 mat to Mexico is also in disagreement. Holburt (1976) states that There is no agreement among the basin states of the interpreta- tion of Me Colorado River Compact with respect to the Mexican Water Treaty obligation of the Upper Basin states. The apparent position of representatives from the four Upper Basin states is Mat Weir obligation is zero. Representatives from the three Lower Basin states take the position diet the obligation is 75O,OOO acre-feet a year plus losses, which could be as much as 150,000 af/yr, giving a total obligation of 900,000 acre-feet a year. These differences have not yet been adjudicated be- cause the development of water uses in the river has not yet brought the matter into sufficient focus to bring about a legal determination. The interstate apportionment for the Lower Basin states was accomplished through the Boulder Canyon Project Act of 1928. Congress decided that a fair division of the first 7,500,000 acre-feet of the mainstream water would give 4,400,000 to California, 2,800,000 to Arizona, and 300,000 to Nevada; Arizona and California would each divide any surplus. The decree in Arizona v. California (1963) divides the surplus as Nevada, 4 per- cent; Arizona, 46 percent; and California, 50 percent. The Upper Basin states reached agreement on a for- mula for further dividing their apportionment under the Colorado River Compact when they executed the Upper Colorado River Basin Compact. The Upper Colorado River Basin Compact of 1948 (1949) allots to Arizona 50,000 acre-feet per annum. The balance is apportioned to Colorado, 51.75 percent; New Mexico, 11.25 percent; Utah, 23.00 percent; and Wyoming, 14.00 percent. Indian tribes were not parties to either the interre- gional allocation of the 1922 Compact or the interstate allocation of the 1948 Compact. Tribal water claims are based on the Winters Doctrine (Winters v. United States, 1908), which holds that the rights are not lost by nonuse but can persist indefinitely in an unquantified state. The reserved rights of five tribes in the Lower Basin have been adjudicated and quantified. The current maximum diversion quantity is 1 maf per annum. The consumptive use, which is a measure of the river depletion, is esti- mated to be approximately 615,000 acre-feet per year (Holburt, 1976~. JOHN A. DRACUP It is anticipated that any further allocations to the In- dian reservations will come out of the allocation of the state that contains the reservation. The intrastate allocation is based on the doctrine of property ownership in water. This doctrine was de- veloped to meet the needs of the area on a basis entirely foreign to the riparian doctrine of the English common law from which the United States derives its general system of law. The appropriation doctrine of the West is based on the proposition that whoever will invest the energy necessary to apply water of natural streams to beneficial use shall be protected in his right to use as against any later water developers. This right is limited to divert only what is needed for beneficial use. The title to the water is perpetually reserved in the people of the various states. This is subject to the right of the individual appropriator to take what he needs for beneficial use on the basis of "prior in time is prior in right." SURFACE-WATER RUNOFF About 83 percent of the water that flows in the Colorado River Basin comes from the Upper Basin. The average annual precipitation throughout the entire Upper Basin is about 16 inches, which amounts to 93,440,000 acre-feet per year. Thus, approximately 15 percent runs off as most of the precipitation is lost to evapotranspiration in the Upper Basin. One of Me most famous and controversial hydrologic records in the United States is that of the virgin flow of We Colorado River at Lee Ferry, Colorado. Lee Ferry is defined as a point on the Colorado River, one mile below the mouth of the Paria River. Estimates of the virgin flow have been made for the Upper Basin since 1896; how- ever, the runoff has actually been recorded since the first gauging station was established at Lee Ferry during Me summer of 1921. The importance of this flow is accen- tuated by the Colorado River Compact, which anticipates that the Upper Basin can deliver 75 maf at Lee Ferry each 10 years. Estimates of the long-term annual average flow vary from 11.8 to 16.8 maf depending on the time period selected (see Table 8.1~. Others estimate the long-term average to vary from 13.09 to 15.09 mar, again depending on Me time period selected (see Table 8.21. Recent tree- ring analysis dating back to 1512 has indicated the long- term mean to be approximately 13.5 maf (Stockton, 1976~. Using his tree-ring indicator study of the Upper Col- orado River Basin, Stockton (1976) states Mat The early part of the 20th Century was characterized by a period of anomalously high sustained flow, the longest in the entire 450 year reconstruction. He goes on to say: Based on the foregoing evidence, it is apparent that within Southwestern United States, climatic change has occurred over a fairly short time span and it appears to have been reflected in the annual runoff, at least for the Upper Colorado River Basin.

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Impact on the Colorado River Basin and Southwest Water Supply TABLE 8.1 Colorado River at Lee Ferry, Arizona, Estimated Average Annual Virgin Flowa Period Average Annual Virgin Flow (million acre-feet) Remarks 1896-1968 1896-1929 1930-1968 192~1966 191~1923 1931-1940 Total Flow 1917 1934 14.8 16.8 13.0 13.8 18.8 11.8 24.0 5.6 73-year period of measured flow and estimates by fed- eral agencies 34-year "wet period" 38-year "dry period" 45-year period of measured flow 10-year wettest period 10-year driest period Maximum single year Minimum single year Quantities are for water years October 1-September 30, inclusive. Gauging station established in 1921. Prior to 1922 estimates are based on measurements at upstream stations. (Colorado River Board of California, 1969.) TABLE 8.2 Estimates of Average Virgin Flow for the Upper Colorado River Basina Period Million Acre-Feet per Year 1896-1968 1906-1965 1914-1965 1922-1965 1931-1965 14.82 15.09 14.64 13.87 13.09 aWater Resources Council (1970), p. v-12. TABLE 8.3 Colorado River at Lee Ferry, Arizona, Average Five-Year Reconstructed Flow, 151~1961a 125 The resulting reconstructed flow from tree-ring anal- ysis indicates that the lowest five-year flow at Lee Ferry was 8.8 maf per year, which occurred during 159~ 1594 (see Table 8.3~. The lowest ten-year reconstructed flow was 9.7 maf per year, which occurred during 158~ 1593 (see Table 8.4~. This 9.7 maf per year flow is not appreciably lower than the 11.8 maf per year 10-year flow that was recorded during 1931-1940 (see Table 8.1~. The current estimates of available surface-water supply within the Upper Basin are less than those at the time the Colorado River Compact was negotiated. This is because of the abnormally wet period that occurred during the early part of this century. The range of annual flow at Lee Ferry has varied from a low of 5.6 maf in 1934 to a high of 24.0 maf in 1917. Some argue that the average flow of 13.1 maf per year that has occurred since 1931 is closer to the long-term mean ~ Jacoby, 1975a, 1975b). A Bureau of Reclamation hypothesis indicates that 5.8 maf per year should be used as a conservative amount of water available for consumptive use in the Upper Basin (U.S. Depa~l~ent of the Interior, 1974~. Other studies have used different basic assumptions and have applied other factors that have resulted in both higher and lower annual estimates. However, there are undoubtedly those who make different assumptions on the basis of differing interpretations of the impact of the Colorado River Com- pact. The amount of water currently being consumptively used in the Upper Basin is approximately 3.7 maf per year. Therefore, 2.1 mat of Me conservative 5.8 maf is presently not being utilized (U.S. Department of the Interior, 1974~. The groundwater utilization in the Lower Basin is currently greater Man its annual safe yield (Water Re- sources Council, 19701. Over 60 percent of all withdraw- als in the Lower Basin come from groundwater. Annual groundwater pumpage has increased from less than 1 million acre-feet in the early 1930's to currently over 5 million acre-feet. The present annual overdraft is about TABLE 8.4 Colorado River at Lee Ferry, Arizona, Average Ten-Year Reconstructed Flow, 151~1961a Years Meansb Years Meansb 1531-1535 9.6 154~1557 17.5 1553-1557 17.9 1583-1592 9.9 1552-1556 17.9 158~1593 9.7 1583-1587 9.0 1585-1594 10.3 1589-1593 9.9 166~1672 10.5 159~1594 8.8 1773-1782 10.5 1667-1671 9.2 1908-1917 17.6 1912-1916 18.0 1912-1921 17.8 1913-1917 19.0 1913-1922 17.8 1914-1918 18.4 191~1923 17.9 am W. Stockton, personal communication (1976). All mean flows are given in million acr~feet per year. ac. W. Stockton, personal communication (1976). All mean flows are given in million acre-feet per year.

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126 2.5 mat, most of which occurs in central Arizona. Whether or not groundwater withdrawal and recharge affect Col- orado River Compact commitments is yet to be resolved; however, it does bear on the demand for Colorado River water. The total water uses that can be derived from these flow estimates vary widely. The Committee on Water (1968) states: . . . use of the 13.8 maf estimate . . . would introduce serious doubts of the feasibility of the Central Arizona Project or of an expansion of Upper Basin uses beyond those existing or au- ~orized, or both. Steiner (1975) claims that if the Upper Basin dedicates this surplus . . . to high economic return uses of municipal, industrial and energy development rather than to low economic return agricul- ture, the remaining entitlement is more than sufficient to meet the needs for energy development in the Upper Basin. Furthermore, Steiner (1975) argues that the minimum annual release to the Lower Basin at Lee Ferry should be 8.4 maf constituted as follows: 7.5 maf under the Compact agreement, plus 750,000 af as one half of the Mexican Treaty requirements plus 150,000 af as one half of the losses associated with delivery of the Mexican agreement. He contends the latter amount of 150,000 af is arguable, but the remaining 8.25 maf is "crystal clear and inescapa- ble." This position is supported by California, Nevada, and Arizona (Holburt, 1976~. Since the Upper Basin has a low consumptive use and inability to store water (see Table 8.5), more water has been historically available to the Lower Basin than the law requires. Nevada has a relatively small demand on TABLE 8.5 Major Reservoirs in Colorado River Basin JOHN A. DRACUP the water, and Arizona is not using as much of the Col- orado River as is its legal allocation. This is because of delays in the construction of the Central Arizona Project. California has facilities to divert more than its legal appor- tionment and has been doing so (State of California, 1972~. However, these diversions are allowed by the documents that make up the "Law of the River." WATER AND ENERGY IN THE COLORADO RIVER BASIN The future key factor in the consumption of water in the Colorado River Basin is the planned and projected energy development, particularly in the Upper Basin. This proposed energy development in the Basin in- cludes steam-electric nuclear, steam-electric coal, geo- thermal, natural gas, crude oil, refineries, oil shale, coal mining, coal gasification, coal liquifaction, and coal slurry pipelines. Each of these energy forms requires a con- sumptive use of water,~as indicated in Table 8.6. This new energy resource development will seek to purchase and convert existing water rights that long have been appropriated for other beneficial purposes. The availability of such rights and the costs of acquisition, development, or both, and the legal constraints will have a major effect on the actual process that will be used in the energy development (Western States Water Council, 1974~. An important aspect of this problem is the eco- nomic multiplier effects that will be lost to a region if water that is currently being utilized for agricultural de- velopment is converted to energy production usage. A summary of pending energy developments in the Upper Basin is shown in Table 8.7. Based on these data, it is Capacity (million-acre-feet) Reservoir Dam Stream Gross Usablea Upstream of Lee Ferry, Arizona (Upper Basin) Fontenelle Fontenelle Blue Mesa Blue Mesa Morrow Point Morrow Point Flaming Gorge Flaming Gorge Navajo Lake Powell Total in Upper Basin Navajo Glen Canyon Downstream of Lee Ferry, Arizona (Lower Basin) Green River Gunnison River Gunnison River Green River San Juan River Colorado River 0.35 0.94 0.12 3.79 1.71 27.00b 33.91 0.34 0.83 0.12 3.75 1.70 25.00 31.74 Lake Mead Hoover Colorado River 28.54 26.16 Lake Mohave Davis Colorado River 1.82 1.81 Lake Havasu Parker Colorado River 0.65 0.62 Total in Lower Basin 31.01 28.59 TOTAL IN UPPER AND LOWER BASINS 64.92 60.33 Capacity above dead storage. Although the capacity of Lake Powell is 27 mar, this quantity has not as yet been realized since filling of the reservoir was initiated in 1963 (Lord, 1976).

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Impact on the Colorado River Basin and Southwest Water Supply TABLE 8.6 Unit Water Consumption Rates for Energy Resourcesa Energy System Steam-electric nuclear Evaporative cooling Pond River Wet-dry radiator Steam-electric coal Evaporative cooling Pond River Dry radiator Geothermal Natural gas Crude oil Refineries Oil shale Coal gasification Coal liquif~cation Coal slurry pipeline Coal mining Vegetation re-establishment aWestern States Water Council (1974). Water Needs 17,000 acre-ft/yr/1000 mW unit 12,000 acre-ftlyr/1000 mW unit 4,000 acre-ft/yr/1000 mW unit 2,000 acre-ft/yr/1000 mW unit 15,000 acre-ft/yr/1000 mW unit 10,000 acre-fVyr/1000 mW unit 3,600 acre-ft/yr/1000 mW unit 2,000 acre-ft/yr/1000 mW unit 48,000 acre-ft/yr/1000 mW unit 50,000 acre-fVyr throughout the West 50,000 acre-Pc/yr throughout the West 39 gal/bbl/crude 7,600 to 18,900 acre-ft/yr/100,00 bar- rels per day plant 10,000 to 45,000 acre-ft/yr/250 million scf per day plant 20,000 to 130,000 acre-ft/yr/100,000 barrels per day plant 20,000 acre-ft/25 million tons coal (1 cfs will transport about 1,000,000 tons per year) 0.5 to 4 acre-ft/acre/yr (some areas may require two years) TABLE 8.7 Summary of Pending Energy Develop- ment, Upper Colorado Basina Coal-Fired Electric Oil Coal ~ 4 Generation Shale Gasification State (MOO) (KBCD) (MCFD) O Wyoming 5,360 125 250 ~ 3 Colorado 8,970 1,090 Utah 10,630 300 864 New Mexico 6,850 - 1,788 Arizona 2,310 2 34,120 1,515 2,902 acre-ft/yr acre-fI/yr Wyoming 79,500 Colorado 134,600 Utah 144,950 New Mexico 82,000 Arizona 34,100 22,000 191,000 46,000 52,500 72,000 475,150 259,000 139,500 aU.S. Department of the Interior (1974). acre-ft/yr Total 15,000 116,500 325,600 243,450 154,000 34,100 - 873,650 127 estimated that approximately 870,000 acre-feet of water will be needed annually for energy development in the Upper Basin by the year 2000. Subsequent events, however, reveal that ~ese projections for water may be overly optimistic. For example, the Kaiparowits Project in Utah, which was assigned 102,000 af, has been canceled by the Sou~em Califomia Edison Company. Further- more, all major oil-shale developments currently have been stopped by private companies pending the resolu- tion of federal loan guarantees and significant environ- mental problems. All of these rapidly changing factors make any projections of water requirements in the Upper Basin difficult at best. Also, in addition to energy uses, ~ere are o~er water needs that must be considered. These include municipal, industrial, agricultural, and en- vironmental water needs. Given that projected water requirements in the Upper Basin will occur, the total depletions in relation to water supply in ~e year 2000 could be essentially as indicated in Figure 8.2. The individual Upper Basin state deple- tions and supplies as of 2000 are shown in Figures 8.~ 8.6. Using these projections, there could be significant shortages occurring in all ~e Upper Basin states except Wyoming by the year 2000. The Colorado River Basin Salinity Control Forum 7 6 1 ASSUMED AVAI LARLF 6 5 MAF CONSFRVATIVE HYPOTHESIS 5.8 MAF ~D FOOD & F I BE R - ~/G=C=~= - ~ ~ EXPORTS ENERGY STORAGE PROJECT RESERVOIR EVAPORATION M & 1, MINERALS, FISH-WILDLIFE, RECREATION, PUBLIC LANDS EXPORTS 1 980 YEAR 1qqn 2000 FIGURE 8.2 Upper Colorado River Basin water for energy 1974 to 2000. (After U.S. Department of the Interior, 1974.) , u~ z 0 _ 2 Z Ul CO LU

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128 (1975) has made projections on the basis of low, medium. and high rates of water use. These are summarized in Table 8.8. A comparison of these values with Figure 8.2 indicates only a difference of 3 percent between the two projections at the high rates in Me year 1990. Major energy facilities also are being planned for con- struction in the Lower Basin. It has been estimated that 141,050 acre-feet/year of Lower Basin water will be re- quired for new electrical power generation facilities by 1984 (.Tacoby, 1975a, 1975b). However, the fossil-fi~el re- sources of the Lower Basin are nowhere near as great as they are in the Upper Basin; therefore, the stress for in situ power production is greater in the Upper Basin. Dreyfus and Cooper (1974) in their study of "Water and Energy Self-Sufficiency" state that Upon closer inspection, however, regional water shortage, even in the Colorado Basin, is more prospective than real. The Col- 1.5 ~ .0 0.5 o UTAH'S SHARE OF 7.5 MAF COMPACT = 1.714 MAF WATER FOR ENERGY FUTURE USEUTAH 1974 TO 2000 UTAH'S SHARE OF _ 6.5 MAF ASSUMED AVAILABLE = 1.483 MAF UTAH'S SHAR E O F 5.8 MAF = 1.322 MAF ~ PROJECTED ENERGY DEV. / ~ BLOOD & FIBER ENERGY DEV. ~ ~ IN PROGRESS, it_ ~ '~ ~ M& I, MINERALS, F,W& Get REC, LVSK, PUBLIC LANDS EXPORTS RESERVOI R EVAPORATI ON PRESENT DEPLETIONS 1 1 1974 1980 YEAR 1990 2000 FIGURE 8.3 Water for energy future use. Utah, 1974 to 2000. (After U.S. Department of the Interior, 1974.) JOHN A. DRACUP WATER FOR ENERGY FUTURE USENEW MEXICO 1974 TO 20 1.0 NEW MEXICO'S SHARE OF 7.5 MAF COMPACT = 0.838 MAF NEW MEXICO'S SHARE OF / 6.5 MAF ASSUMED AVAI LADLE z 0.726 MAF / 5.8 MAF + 0.100 (S.J. RES 123) / NEW MEXICO'S SHARE OF 5.8 MAF = 0.647 MAF PROJECTED ENERGY DEV. _ ...... - a FOOD & FIBER M & I, MINERALS, F. W & REC, LVSK, & PUBLIC LANDS = ~ _ 974 1980 o 1! RESERVOIR EVAPC)RATION PRESENT DEPLETIONS 1 990 YEAR 2000 FIGURE 8.4 Water for energy future use. New Mexico, 1974 to 2000. (After U.S. Department of the Interior, 1974.) orado River system, through a complexity of compacts and water rights, is indeed over-committed in a legal sense. Furthermore, each new consumptive use or degraded return flow adds to the spectre of an ultimate moratorium on any new uses in order to preserve a usable quality for furthest downstream existing rights. The severity of the water resource planning and management problems of the region are undeniable, but the problem is not yet one of physical limitation. . . . In the Colorado Basin, about 90 percent of all existing water uses are for agriculture, much of it inefficiently applied and producing low value crops. Water for new energy uses quite probably will come, in part, from purchases by energy industries of existing agricultural water rights rather than the development of new supplies. There also exist in the Basin aquifers of con- siderable size, particularly saline aquifers with little current utility. In some energy applications, such as materials handling, saline groundwater could be used if runoff to surface streams can be prevented. In their conclusions Hey go on to say There should be a strengthening of Federal activities in river basin planning with a new emphasis on the emerging energy outlook. A national assessment of water for energy, such as has been described, should be initiated immediately and given adequate funding and the highest priority.

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Impact on the Colorado River Basin and Southwest Water Supply FLOW AUGMENTATION Flow augmentation to the Colorado River Basin is a distinctive technical and perhaps an economic possibil- ity. However, it is fraught with legal, political, social, institutional, financial, and environmental problems and thus may never occur. Nevertheless, some individuals and institutions in the Colorado River Basin support the concept that someday there will be flow augmentation and more water will be economically available to the Colorado River Basin. Four such concepts will be briefly discussed here: (1) water importation, (2) cloud seeding, (3) vegetation management, and (4) sea and brackish water desalination. Several schemes have been proposed for interbasin diversions to the Colorado River Basin. Diversions from the Snake River Basin are proposed by some individuals and agencies as being a plausible alternative (Dunn, 1964; Nelson, 1964; Bureau of Reclamation and U.S. Corps of Engineers, 1961~. However, the Colorado River 4.0 3.0 1.0 _ o COLORADO'S SHARE OF 7.5 MAF COMPACT = 3.855 MAF WATER FOR ENERGY FUTURE USECOLORADO 1974 TO 2000 COLORADO'S SHAR E OF 6.5 MAF ASSUMED AVAI LABLE = 3.338 MAF PROJECTED ENERGY DEV. PLANNED ENERGY DEV. ,_~ \ COLORADO'S SHARE OF 5.8 MAF = 2.976 MAF ENERGY DEV. IN PROGRESS ~ ~ ~ FOOD & FIBER EXPORTS \ RESERVOIR EVAPORATION \% \ M & I, LVSK, MINERALS, F & W & REC, & PUBLIC LANDS PRESENT HOPI FTION~ 1 ,. ... _ . .. _. 1974 1 980 YEAR 1 990 2000 FIGURE 8.5 Water for energy future use. Colorado, 1974 to 2000. (After U.S. Department of the Interior, 1974.) 129 WATER FOR ENERGY FUTURE USEWYOMING 1974 TO 2000 WYOMING'S SHARE OF 7.5 MAF COMPACT = 1.043 MAF 1.0 UJ US C' ~ 0.5 o 1 - o WYOMING'S SHARE OF 6.5 MAF ASSUMED AVAI LABLE = 0.903 MAF WYOMING'S SHARE OF 5.8 MAF'0.805 MAF PROJECTED ENERGY DEV. PLANNED FNFR~Y nF\J _ ENERGY DEV. IN PROGRESS ~ ~ ~ FOOD& FIBER & I, DIN it RESERVOIR EVAPORATION ~ EXPORT PRESENT DEPLETIONS 1 974 1 980 YEAR 1 990 2000 FIGURE 8.6 Water for energy future use. Wyoming, 1974 to 2000. (After U.S. Department of the Interior, 1974.) Basin Project Act of 1968, which authorized the Central Arizona Project, included a 10-year moratorium on ''. . . reconnaissance studies of any plan for the importa- tion of water into the Colorado River Basin . . ." (Colorado River Basin Project Act, 1968~. The purpose of this moratorium was that the represen- tatives from the Pacific Northwest wished to protect their water resources for local use and to provide a period during which the extent of local requirements could be accurately determined. Therefore, it is yet to be deter- mined whether the importation of water from the Colum- bia River Basin is a viable alternative for the management of the Colorado River Basin. Cloud seeding has the distinct advantages of low capi- tal investment, a short response time, and a brief required time for implementation (Redul et al., 1973~. Weisbecker (1974a, 1974b) and Hurley (1967) propose that cloud seeding is a viable method to increase signifi- cantly snow storage and the resulting snowmelt runoff in the Colorado River Basin. However, problems concerning the resulting down- wind effects, the increased probabilities of avalanches, and the increased probabilities of flooding are all im- portant disadvantages. Meteorologists are still uncertain concerning the total effectiveness of cloud seeding (Committee on Atmospheric Sciences, 19661. The Bureau of Reclamation's July 1974 Project Skywa-

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130 TABLE 8.8 Summary of Estimated Water Use in Colorado River Basina b (1000 acre-feet) JOHN A. DRACUP 1973 Assumption Base as to Rate Condition of Use 1980 1985 1990 Upper BasinC 2976 Low 3,426 3,686 4,111 Moderate 3,576 4,176 4,594 High 4,021 4,589 5,464 Lower Basins 6143 Low 5,813 6,238 7,461 Moderate 5,953 6,838 7,476 High 6,203 8,168 7,500 TOTAL 9119 Low 9,239 9,9~ 11,572 Moderate 9,529 11,014 12,070 High 10,224 12,757 12,964 aColorado River Basin Salinity Control Forum (1975). Does not include deliveries to Mexico. CDoes not include CRSP reservoir evaporation estimated by the USER to average 520,000 acre-feet per year. Diversions from the main stem less returns. Does not include main stem reservoir evaporation and steam losses estimated by the Forum to average 1,400,000 acre-feet per year. ter Newsletter reported on the Colorado River Basin Pilot Project. The results indicated the doubtful reliability of weather modification to increase runoff. Furthermore, Weisbecker (1976) reported that the five-year San loan cloud-seeding program by the Bureau of Reclamation in the Upper Colorado River Basin provided "no signif~- cant added precipitation." In spite of these results, many people strongly believe that weather modification is the panacea for solving the water-supply problems in the Upper Basin. However, certainly in the short run, cloud seeding does not appear to be a viable alternative for significantly increasing the runoff in the Colorado River Basin. The removal of phreatophytes and the management of vegetation in the southwestern United States can result in substantial increases in streamflow (Ffolliott and Thorud, 1974~. However, this methodology also can cause in- creases in salinity, sedimentation, and associated ecologi- cal disturbance (Hibbert et al., 1974; Brown et al., 1974~. This entire approach can only be implemented when all the land and water resources in the region are considered as a complete ecological system. It would appear that vegetation management could only have limited effect on the Colorado River Basin at the present time. The desalination of sea and brackish waters also have been considered as a possibility for increased water sup- ply to the Colorado River Basin. However, recent in- creases in energy costs have resulted in substantial in- creases in the cost of desalinated water. Therefore, this alternative only is viable in a local context such as the Colorado River International Salinity Control Project (U.S. Department of the Interior, 1973~. It appears from, these alternatives that no significant flow augmentation is available in the immediate future. EFFECTS OF A DROUGHT ON THE COLORADO RIVER BASIN The picture here has been painted of a limited resource stressed by a myriad of demands and with limited if any sources for augmentation and relief. What happens then if the climatic stress of drought is further added? To answer this question one must include one more important con- sideration in the analysis. That is, the storage capacities in the entire Basin (see Table 8.5~.* Lake Mead behind Hoover Dam in the Lower Basin contains approximately 27 maf of storage capacity. Lake Powell behind Glen Canyon Dam is located just upstream of Lee Ferry. It contains about 80 percent of the total Upper Basin active storage capacity of 33.8 mat (Upper Colorado River Commission, 1970). These are He two main storage res- ervoirs in the Colorado River Basin, and Hey have stor- age capacity in excess of four tinges the annual flow of the river. Since there is limited storage capacity upstream in the Upper Basin, the current storage capacity configura- tion obviously favors the Lower Basin. With this background one can now summarize the fol- lowing situation in the Colorado River Basin: 1. A system with strong institutional division between the Upper and the Lower Basins. 2. Legal constraints that require certain releases from the Upper to the Lower Basin. 3. A storage configuration that favors the Lower Basin. 4. Extensive energy development projected for the Upper Basin. *It should be noted that there is a difference between the storage capacity available and the actual water in storage at any one time.

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Impact on the Colorado River Basin and Southwest Water Supply It would appear, therefore, that any major basinwide drought could have significant and damaging effects on the Upper Basin. To envisage Me extent of damage to Me Upper Basin that might occur from such a drought, one should study Figure 8.2. Suppose, for example, the 10-year 1584~1593 drought, which resulted in an average annual flow of 9.7 mat at Lee Ferry, occurred once again. Furthermore, suppose that the maximum available 31 maf of water was stored in the Upper Basin at Me onset of the drought. Potentially, a total of 82.5 maf may be legally required to be delivered to the Lower Basin during any 10-year period.* A 10-year drought flow of 97.0 maf would leave the Upper Basin with 14.5 maf plus a potential 31 maf in storage. Thus 45.5 maf would be available to the Upper Basin during this 10-year period, or an average annual amount of approximately 4.6 maf. From Figure 8.2 it is immediately obvious that such a drought would affect the projected water demands of the Upper Basin if it occurred after 1982. A myriad of similar scenarios could be considered. For example, during 1931-1940 the average annual flow was 11.8 maf (see Table 8.1~. The active storage in the Upper Basin available September 30, 1974, was 23.6 mat (Colorado River Board of California, 19741. Assuming this storage value at the beginning of a 11.8 maf total 10-year flow and an 82.5 maf 10-year delivery to the Lower Basin leaves the Upper Basin with 59.1 maf available during this 10-year period, or an average annual amount of approximately 5.9 maf. Again from Figure 8.2, it is obvious that such a drought would affect the projected water demands of the Upper Basin if it occurred after 1992. Much of this water is projected to meet the needs of expanding food, fiber, and energy development. The energy demand for water is not seasonal, as irrigation and municipal water supply demands, but requires a rela- tively constant year-round supply. Since those energy projects are such capital-intensive developments, it seems foolhardy to continue with these projects without a guaranteed annual water supply in the face of a severe drought. Mitigating circumstances are considerations of specific locations of each of the energy projects in the Upper Basin and Weir adjacent water supplies. That is, the macroview of the Upper Basin distinctively indicates significant future shortages under a drought condition. However, the microview of each project may be less severe in some cases. This analysis remains to be com- pleted elsewhere. Further work that needs to be accomplished includes *Ten-year totals of 75 maf under the compact agreement plus 7.5 maf as one half of the Mexican agreement. (Note: The Lower Basin states contend that 84 maf would be required during this period, and the Upper Basin states contend that 75 maf would be required.) 131 the consideration of scenarios of 3-, 5-, 7-, and 10-year droughts in the Upper Basin and an evaluation of their macroeconomic and microeconomic effects on the region and the nation. RE FE BE N C E S Arizona v. California, 1963, 373, U.S. 546; Decree 376 U.S. 340 (1964~. Brown, H. E., et al. (1974). Opportunities for increasing water yields and other multiple use values on Ponderosa pine forest lands, USDA, Forest Service Research Paper RM-129, Ft. Collins, Colo. Bureau of Reclamation and U.S. Corps of Engineers (1961). Upper Snake River Basin, Vol. 1, Summary Report. Colorado River Basin Project Act (1968). Public Law 90-537, 82 Stat. 885. Colorado River Basin Salinity Control Forum (1975). Proposed Water Quality Standards for Salinity I ncluding Numeric Criteria and Plan of Implementation for Salinity Control, Colorado River System, Table 3, p. 27, June. Colorado River Board of California (1969). California's stake in the Colorado River, Los Angeles. Colorado River Board of California (1974). Annual Report. Colorado River Compact (1922). 70 Congressional Record 324, 325, 1928; Nov. 24. Committee on Atmospheric Sciences (1966). Panel on Weather and Climate Modification, Weather and Climate Modifica- tion: Problems and Prospects; Vol. 1, Summary and Recom- mendations; Vol. 11, Research and Development, National Academy of Sciences-National Research Council, Washing- ton, D.C. Committee on Water (1968). Water and Choice in the Colorado River Basin, National Academy of Sciences, Washington, D.C., p. 8. Dolan, R., A. Howard, and A. Gallenson (1974~. Man's impact on the Colorado River in the Grand Canyon, Am. Sci. 62, 392. Dreyfus, D. A., and B. S. Cooper (1974~. "Water and Energy Self-Suff~ciency," Committee on Interior and Insular Affairs, U.S. Senate, S. Res. 45, The National Fuels and Energy Policy Study, Washington, D.C. Dunn, W. G. (1964). Modified Snake-Colorado Project, presented before the California State Senate Fact Finding Committee on Water and Assembly Interim Committee on Water, Sacra- mento. Ffolliott, P. F., and D. B. Thorud (1974). Vegetation Manage- ment for Increased Water Yield in Arizona, U. of Arizona Tech. Bull. 215. Hibbert, A. R., E. A. Davis, and D. G. School (1974). Chaparral conversion potential in Arizona, Part I: Water yield response and effects on other resources, USDA Forest Service Research Paper RM-126, Ft. Collins, Colo. Holburt, M. B. (1976). Personal communication, Aug. Hurley, P. A. (1967~. Augmenting Upper Colorado River Basin water supply by weather modification, presented to ASCE, Na- tional Meeting on Water Resources Engineering, New York, Oct. Jacoby, G. C., Jr. (1975a). Lake Powell Effect on the Colorado River Basin Water Supply and Environment, Lake Powell

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32 Research Project Interim Rep., Institute of Geophysics and Planetary Physics, UCLA, May. Jacoby, G. C. (1975b). Overview of water requirements for electric power generation, Lake Powell Research Project Interim Report, presented at Symposium on Water Require- ments for Lower Colorado River Basin Energy Needs, Tucson, Ariz., May. Lord, C. R. (1976~. Personal communication, Aug. Meyers, C. J. (1966~. The Colorado River, Stanford Law Rev. 19, Jan. Nelson, S. B. (1964~. Snake-Colorado Project, Los Angeles De- par~nent of Water and Power. Piper, A. M. (1965~. Has the United States enough water? USGS Water-Supply Paper 1797, p. 11. Redul, R. K., H. J. Stockwell, and R. G. Walsh (1973~. Weather modification: An economic alternative for augmenting water supplies, Water Resources Bull., 9, 116. Saunders, G. G. (1976~. Personal communication, Aug. State of California (1972~. Hydrologic Data: 1970 Department of Water Resources Bull. 130-70 V, p. 60. Steiner, W. E. (1975~. Water for energy as related to water rights in the Colorado River Basin, in Proceedings of the Conference on Water Requirements for Lower Colorado River Basin Energy Needs, U. of Arizona, Tucson, p. 67. Stockton, C. W. (1976). Interpretation of past climatic variability from paleoenvironmental indicators, presented at AGU Con- ference, Washington, D.C. Upper Colorado River Commission ~ 1970~. Twenty-Second Annual Report. Upper Colorado River Basin Compact (1948~. October 11 (ap- proved by Congress April 6, 1949~. JOHN A. DRACUP U.S. Department of the Interior (1973~. Office of Saline Water, Colorado River Salinity Control Project Special Report, Executive Summary. U.S. Department of the Interior (1974~. Report on Water for Energy in the Upper Colorado River Basin, Water for Energy Management Team, July. Water Resources Council (1970~. Lower Colorado Region Comprehensive Framework Study, App. V, Water Resources. Watkins, T. H., et al. (1969~. The Grand Colorado, The Story of a River and Its Canyons, American West Publishing Co., Palo Alto, Calif. Weatherford, G. D., and G. C. Jacoby (19751. Impact of energy development on the law of the Colorado River, National Resources J. (the U. of New Mexico, School of Law), pp. 171-213. Weisbecker, L. W. (1974a). Snowpack Cloud-Seeding, and the Colorado River A Technology Assessment of Weather Mod- ification, U. of Oklahoma Press, Norman, Okla. Weisbecker, L. W. (1974b). The Impacts of Snow Enhance- ment Technology Assessment of Winter Orographic Snow- pack Augmentation in the Upper Colorado River Basin, U. of Oklahoma Press, Norman, Okla. Weisbecker, L. W. (1976~. Weather modification in the Upper Colorado River Basin as a source of water for energy develop- ment, presented at the Conference on Water for Energy Development, Pacific Grove, Calif., Dec. Western States Water Council (1974). Western states water requirements for energy development to 1990. Winters v. United States, 1908, 207 U.S. 564.