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Background The Colorado River begins in the upper elevations of Wyoming, Colorado and New Mexico and flows southwest through the high deserts of the Colorado Plateau and the low deserts of the Sonoran and Mojave. At its terminus is a great delta formed by eons of sediment deposition transported from the mighty upstream canyons. The river naturally terminates in the Sea of Cortez near Puerto Penasco, Mexico. "Natural" hardly describes the river system anymore. With reservoir storage capacity nearly five times its annual flow rate and demands that exceed its annual flow rate, the highly regulated river rarely reaches the Sea of Cortez. The river basin was divided into Upper and Lower Basins in 1922 with the dividing line situated at Lee Ferry, a point on the Colorado one mile below the mouth of the Paria River (a). The Upper Basin includes all of the Utah, Colorado, Wyoming and New Mexico portions of the basin and the portions of Arizona that drain to the river above Lee Ferry. The Lower Basin includes the remainder of Arizona, Nevada, and California. Early studies by the U.S. Geological Survey estimated annual flows at Lees Ferry to be 16.8 million acre-feet/year (maf/yr). These studies were based on three years of gauging at Lees Ferry and reconstituted flows at gages up and downstream. The negotiators of the Colorado River compact assumed an average annual flow at Lee Ferry of 16 maf/yr. They divided the river into equal apportionments of 7.5 maf/yr for both the Upper and Lower Basin, allowing a 1.0 maf/yr surplus that would be available to the Lower Basin. The Bureau of Reclamation estimated in 1988 that the average inflow to Lake Powell was 11.55 maf/yr from 1963 to 1986 and that the average from 1914 to 1957 was 12.71 maf/yr. Dale Pontius, in his Colorado River Basin Study for the Western Water Policy Review Advisory Commission (1), catalogs flow volumes and notes their extensive variability in various time periods. As he notes, "the wettest 10-year period on record (1914 to 1923) saw an average annual flow of 18.8 maf" and also indicates that "tree-ring studies covering hundreds of years suggest a long-term average annual flow of about 13.5 maf/yr." Unfortunately, the river's waters were apportioned during the wettest period in the last 100 years. Three major tributaries, the Green, the Colorado, and the San Juan rivers, join to form the Colorado River above Lee Ferry. The Green River headwaters are in the Wind River and Wyoming Range mountains of western Wyoming. The largest reservoir on a Colorado River tributary is behind the Bureau of Reclamation's Flaming Gorge Dam on the Green River. The average annual flow of the Green at Flaming Gorge is about 1.5 million acre-feet. Downstream of Flaming Gorge, at Echo Park in Dinosaur National Monument, another major tributary, the Yampa River, joins the Green. The Yampa remains free-flowing with no storage facilities and would be a refuge for native fish, were it not for the presence of predatory non-native northern pike and channel catfish. The Colorado River, originally called the Grand River, begins in the Rocky Mountains of Colorado. The mainstem heads in the Gore Range, Never Summer Range, and Grand Lake in Rocky Mountain National Park. There are 17 transmountain diversions taking water from the mainstem tributaries to the Front Range metropolitan area of Denver. The biggest of these is the Colorado/Big Thompson, which supplements irrigation and municipal water for northern Colorado. The Blue River, a major tributary to the mainstem has both the Green Mountain Reservoir and Dillion Reservoir, which is relied on by the Denver Water Department, the largest water utility on the Front Range. The largest tributary to the Colorado River mainstem in Colorado is the Gunnison River originating in the Elk, Collegiate, Sauguche, and the north side of the San Juan Ranges with the Aspinall Unit (Blue Mesa, Morrow Point and Crystal Reservoirs) located half-way down the river basin. The Aspinall Unit is just above the Black Canyon of the Gunnison, a 2000-foot deep gorge that provides the river an entrance to the Colorado Plateau. There are many smaller reservoirs in the various tributaries throughout Colorado. The Colorado and the Green River join downstream of Moab, UT in Canyonlands National Park at the upstream end of Cataract Canyon. Forty miles downstream from the confluence, after dropping through several hundred feet of rapids, begins the famous and now inundated Glen Canyon. Glen Canyon was a little known but spectacular array of fanciful and beautiful rock formations with narrow slots, arches, and giant spires, only the topmost parts of which are visible above the waters of Lake Powell. Now, when the reservoir behind Glen Canyon Dam is full, half of Cataract Canyon is also inundated. Joining the Colorado midway through Glen Canyon is the San Juan River. This much smaller tributary drains the mountains of northern New Mexico and southwestern Colorado before flowing through southern Utah, past the towns of Bluff and Mexican Hat, and entering Lake Powell. Navajo Reservoir on the San Juan is the third largest reservoir in the Upper Basin behind Lake Powell and Flaming Gorge. Of the total flow at Lees Ferry discussed above, about 45% comes from the Colorado, 40% from the Green and 10% from the San Juan. The remaining 5% is from tributaries to Glen Canyon. The two largest of these are the Escalante and Dirty Devil, which drain the high plateaus of southern Utah. The hundreds of slot canyons contribute small flows on an annual basis, but on any given day can add large amounts, sometimes causing shock waves on the reservoir. Below Lee Ferry, the Colorado enters the 5000-foot deep Grand Canyon. It also enters a much drier watershed. While some of the tributaries seem mighty to local residents, the annual flow of all Lower Basin tributaries is less than 15 % of the total flow at Lees Ferry. Most of the water used along the Colorado River originates in the Upper Basin. It is worth noting that the percentages just presented are based on variable periods of record. The Lower Basin tributaries, by definition, enter the Colorado River below Lee Ferry. The Little Colorado River, draining the high Mogollon Rim, Chugach Mountains and White Mountains of eastern Arizona, enters through deep canyons at the upstream end of the Grand Canyon. While the Little Colorado occasionally contributes huge flood flows, during dry periods, the river is intermittent and the only flows reaching the mainstem surface in Blue Springs five miles upstream of the confluence. Blue Springs get their name from the bluish tint imparted by a combination of calcium carbonate, brought to the surface by the springs, and the fine silt. The Little Colorado River provides necessary refuge for the humpback chub, one of the remaining endangered fishes in the basin. The tributaries in the Grand Canyon are very small with a few perennial tributaries and several ephemeral ones. The contribution to annual flow of the river is negligible when compared to their beauty and ecological importance. For example, the Kanab ambersnail exists only in spring-fed, remarkable falls known as Vasey's Paradise. Below the Grand Canyon, there are essentially no small stream tributaries but there are three relatively large rivers, the Virgin, the Gila, and the Bill Williams Rivers. The Virgin River, which drains southwest Utah and southeast Nevada, enters a major arm of Lake Mead northwest of Las Vegas. The Virgin River drainage has several small reservoirs and is currently being considered for additional water supply reservoirs by Washington County in southwest Utah. Washington County is one of the fastest growing areas of Utah, and a proposal to develop a new town of 35,000 on school trust lands in the county has been advanced. Utah has concluded that the Virgin River and Kanab Creek are subject to the exclusive use of the State, based on the Supreme Court Decree in Arizona v. California. Current projections from the Utah Division of Water Resources are that depletions from these waterways will increase from 81,000 af in 1990 to 145,000 af in 2040. These depletions will decrease the flow in the lower Colorado River resulting in less water available on an annual basis to the Lower Basin. Below Lake Mead, the Bill Williams River enters the Colorado in Lake Havasu. A combination of the Santa Maria River, the Big Sandy, and Burro Creek, the Bill Williams River drains the Sonoran Desert mountains of northwest Arizona. The reservoir at the confluence of the Santa Maria and Big Sandy, the Alamo Reservoir, may be one of the largest but least known Federal water boondoggles. Built for flood control by the Corps of Engineers, there is no development along the mainstem below the dam. Although the Corps has attempted to find users, there is no contract for water delivery from the reservoir to any water user. In other words, this may be the most useless (unless we consider warm water fisheries) reservoir in a region of many reservoirs. Just above Yuma, AZ, the Gila River was, historically, a major tributary. It drains most of southern Arizona, southwestern New Mexico, and some of northern Mexico. Its tributaries include the Santa Cruz, Salt, San Pedro, and Blue Rivers, which drain the highlands of southwest New Mexico and eastern Arizona. In its currently developed condition, the Gila River rarely flows into the Colorado River. This fact is striking when compared to the average annual flows prior to major development; the average annual flow of the Gila from 1904 through 1920 was slightly in excess of 1.1 maf. Flows over that period also demonstrate the episodic character of desert flows with the greatest one-year flow totaling 4.67 maf and the smallest less than 74,000 af. Similarly, five-year averages in that timespan ranged from 271,000 af to 1.73 maf. Two mainstem reservoirs, the San Carlos upstream and Painted Rock downstream, control the mainstem flows. The Santa Cruz River is drained by groundwater usage in Tucson. The Salt River has five major reservoirs and provides the bulk of water for urban and irrigated areas near Phoenix. The only flow in most years passing Phoenix is wastewater return flow; it is subsequently used for cooling water at the Palo Verde nuclear power plant. Average annual flows do not begin to explain the hydrology of the Colorado River basin. Under natural conditions, the river almost never flows at its average annual flow rate. Seasonality controls the annual high and low stages and sediment transport on the river. Seasonal cycles are controlled by snowmelt in the headwaters and winter rains on the lower tributaries. Peak river flows occur from May through July as the Rocky Mountain snows melt. The lowest annual mainstem flows occur in the late summer. High flows in the winter and early spring result from heavy rains and rain on snow events in the mountains of the Lower Basin flooding the Bill Williams, Gila, or Virgin Rivers. High, short duration peaks in the Glen and Grand Canyon regions occur in the late summer due to heavy monsoon-driven thunderstorms. The source and timing of flooding also controls sediment movement throughout the basin. With development of at least 22 reservoirs on the mainstem and major tributaries (not including the Lower Basin tributaries), the mainstem flows have begun to resemble a plumbing system. Annual peak flows have been decreased by up to tenfold; annual low flows at Yuma are at least five times higher than predam conditions. The reason for this is that irrigation demands in California and Arizona peak in late summer. Municipal demands in Las Vegas also peak in the summer. Thus, the reservoirs, when managed as designed, take the top off the peak flows in late spring and early summer and distribute them far more evenly throughout the year. Evaporation and bank storage losses in all of the main reservoirs claim as much as 15% of the annual flow in the river system. The far downstream end of the river below Morelos Dam, the Delta in Mexico and Sea of Cortez, receives water only in rare years, when there is a sufficient surplus in the system that more flow than Mexico's entitlement is delivered, and Mexico is unable to use the surplus. The old adage, "too thick to drink, too thin to plow," indicates that it is not only variation in flow rate but also variation in sediment transport that are central to the basin ecosystem. Sediment transport varies much more than the flow rate from year-to-year. Early in the 1900's, high flows following a drought caused four times the annual sediment flow (up to 150,000 af/yr at Lees Ferry) as occurred after 1941. Since, 1963, sediment has accumulated in the reservoir behind Glen Canyon Dam, largely in the upstream delta, at the rate of 37,000 af/yr. (2) In the early part of the century, basinwide range conditions were at a minimum due to extended drought and increased livestock grazing. Subsequent high-flow years initiated a cycle of erosion that caused both many deep gullies in the Southwest and also high sediment loads on the Colorado River, most of which were deposited below Topock Gorge, just above Lake Havasu. There are various reasons for the drop in sediment after 1941, but the primary one is that a geomorphic threshold was exceeded during the just mentioned high-flow years. Sediments are of great importance to the ecosystem as they are the primary source of nutrients and of the seedbeds necessary for riparian and wetland vegetation. The episodic nature of sediment flow throughout the basin has been well documented. According to Andrews (3), "the decrease in mean annual sediment loads in the Colorado River near Grand Canyon after 1941 is quite large, nearly 100 million tons/year..." (90,718,000 English tons/year). This period also is the period with the best sediment gauging. The average flow at Lees Ferry drops to less than 60,000,000 tons/year from a five-year average of 186,000,000 tons/year. In Utah for example, the average load at Cisco is 8,000,000 tons/year, a drop of 10,000,000 tons/year from the 1930 to 41 average; the average load at Bluff became 18,000,000 tons/year, where the previous average had been 44,000,000 tons/year; and the average load at Green River became 15,000,000 tons/year, where the average from 1930 to 1941 had been 24,000,000 tons/year. By far, the San Juan River at Bluff had the largest decrease. Tributaries within Glen Canyon add almost 20% of the sediment inflow in less than 5% of the water inflow. Although the difference in pre-1941 and post-1941 sediment loads may seem to be largely due to climate changes, the many reservoirs built along the river actually have had much greater effect. Most of the runoff in the San Juan River is in the higher elevation headwaters while most sediment results from the lower reaches. Almost 80% additional sediment results from 10% additional flow. Similar results are seen on the Colorado River. For their flow, the Little Colorado and Paria River contribute much more sediment than any other portion of the watershed. This is clear evidence that upper watersheds contribute most of the water flow while watersheds on the Colorado Plateau contribute most of the sediment. Flaming Gorge Reservoir Dam operations have caused major aggradation (alteration of streambed morphology by sediment deposition) on the Green River. Midchannel bars below the Yampa River indicate that the available load on the Green exceeds the river's transport capacity. Transport capacity decreases as the annual peaks decrease. As much as 500,000 af of sediment is bound within the Green River between the Yampa River and Cataract Canyon. Reoperation of the Flaming Gorge Dam to more closely mimic the natural hydrograph should help move some of this stored sediment further downstream and into Lake Powell. The Lower Colorado Basin, including the Delta, is currently sediment starved. Lake Powell effectively traps all incoming sediment. The Paria and Little Colorado contribute about 15% of the predam load to the Grand Canyon. While the river often cannot transport this load, it is deposited at depth so that it is not useful to riparian communities. Any sediment escaping the Grand Canyon, as well as the Virgin River load, is deposited in Lake Mead. The Bill Williams River load is deposited in Alamo Reservoir. Only the Gila River and bank sloughing, which is largely constrained by riprap programs, contribute significant sediment to the lower river. There is substantial sediment at high channel levels, some of which was deposited in the early 1900's, but the plumbing system does not allow river flows to reach these levels anymore. The Law of the River is an accumulation of numerous compacts (interstate agreements ratified by Congress), legislation, treaties (international agreements), intrastate agreements, and court decisions (disagreements between states are heard and decided by the U.S. Supreme Court). The foundation of the Law of the River is the Colorado River Compact of 1922, signed in 1923 by six of the seven basin states (Arizona did not sign the Compact until 1944). Based on the high estimate of annual flow in the Colorado River system, the 1922 Colorado River Compact split the flows of the Colorado River into 7.5 maf/yr for the Upper and Lower Basin. The compact requires the Upper Basin to deliver an average 7.5 maf/yr, over every ten-year period, to the Lower Basin at Lee Ferry. After that, the Upper Basin may develop up to 7.5 maf/yr in consumptive uses. With the lower, observed flows, the Upper Basin may develop the difference between the annual flow at Lee Ferry and 7.5 maf/yr. Any annual surpluses go to Lower Basin states. The Upper Basin currently absorbs the entire effect of the overestimate of flow. The issue of how the waters in the tributaries in the Lower Basin are allocated has not yet been fully adjudicated. The 1928 Boulder Canyon Project Act, which authorized the construction of Hoover Dam (originally Boulder Dam) creating Lake Mead, also divided the Lower Basin's share among California, 4.4 maf; Arizona, 2.8 maf; and Nevada, 300,000 af. While California and Arizona have allocated the majority of their apportionment to agricultural use, Nevada uses most of its allocation for Las Vegas with a small proportion going to two Indian reservations. Irrigation with that water is almost nonexistent. The California Seven-Party Agreement was signed in 1931 by Imperial Valley Irrigation District (IID), Coachella Valley Water District (CVWD), Palo Verde Irrigation District (PVID), Metropolitan Water District of Southern California (MWD), Los Angeles Department of Water and Power, the City of San Diego, and San Diego County. The latter three water agencies conveyed their water rights to MWD. MWD takes its water from Lake Havasu above Parker Dam through the Colorado River Aqueduct. Further downstream, IID and CVWD get their water from a diversion at Imperial Dam through the All American Canal. The extent of these diversions in the Lower Colorado Basin is difficult to comprehend. Above Parker Dam, the Colorado River Aqueduct diverts 1.2 maf/yr, and across the reservoir, the Central Arizona Project is pumping 1.6 maf/yr to Phoenix and Tucson. The last U.S. diversion, Imperial Dam and Canal is taking 3.1 maf/yr into the Imperial and Coachella Valleys' agricultural lands. The 1963 Arizona v. California Supreme Court decision upheld the 1928 Act. The court's 1964 decree also provided for California to receive 50% of any surplus water, Arizona 46%, and Nevada 4%. The Boulder Canyon Project Act in conjunction with the Arizona v. California decree established the Secretary of Interior as the watermaster of the lower Colorado River. One of the unique authorities of the watermaster is to determine if and when surplus, average, or shortage conditions exist on the lower Colorado River. In 1944, the United States entered into a treaty with Mexico, which requires the U.S. to deliver 1.5 maf of Colorado River water to Mexico annually. Each basin is required to supply half of that water to Mexico from its apportionment. The treaty was amended, in 1973, to include a water quality component. That "minute order" restricts the salinity of Colorado River water when it crosses the border. In 1948, the Upper Colorado River Compact was signed by the four Upper Basin states. Annual flows in the Upper Basin are apportioned as percentages of the remaining flows after the Upper Basin portion of Arizona receives 50,000 af/yr. The apportionment for Colorado, New Mexico, Utah, and Wyoming, respectively, is 51.75, 11.25, 23, and 14% of the Upper Basin use. These allocations were based on the amount of Colorado River watershed providing water in each state. The Compact led to the establishment of the Upper Colorado River Commission, which is responsible for coordinating water management in the Upper Basin. In the Lower Basin, the Secretary of the Interior controls the federal facilities, their operation, and issues contracts on use. Although the Secretary remains responsible for the operation of all facilities in the Upper Basin, the Upper Colorado River Compact retained each upper basin state's power to allocate water under state law, rather than through the Secretary. The 1956 Colorado River Storage Project Act (CRSP) provided funding for the construction of four major dam projects in the Upper Basin and authorized study of numerous other projects that would be funded by the hydropower revenues produced by these four dams. The projects authorized by CRSP are: Glen Canyon Dam on the mainstem of the Colorado River just upstream of the Grand Canyon; Flaming Gorge Dam on the Green River at the Wyoming-Utah border; Navajo Dam on the San Juan River at the Colorado-New Mexico border; and the Aspinall Unit, consisting of three dams, Blue Mesa, Morrow Point, and Crystal, east of Montrose, CO, on the Gunnison River. These four complexes produce significant revenue that is intended to pay for the cost of building these dams as well as to provide funds to build other projects that don't have economic justification as stand-alone projects. The most economically questionable of these other projects is the Animas-La Plata Project (ALP). Glen Canyon Dam was authorized for construction by Congress in April 1956, and the dam was essentially completed in 1963, followed by completion of the power plant in 1964. The purpose was to create another storage reservoir along the Colorado River for maintaining allocated water supplies and for hydroelectric generation. Because CRSP and the construction of Glen Canyon Dam occurred before the passage of both the National Environmental Policy Act and the Endangered Species Act, no environmental studies on the impact of Glen Canyon Dam on the Colorado River ecosystem were done until the 1980s. Archeological and biological investigations consisting of surveys and salvage were conducted by the Museum of Northern Arizona and the University of Utah in the late 1950's. The majestic gorge of the Grand Canyon, carved by the annual torrents of the Colorado River over millennia, stands in stark contrast to the flat water of Lake Powell, the reservoir that buries the magnificent multi-lobed canyon behind Glen Canyon Dam. Glen Canyon Dam now controls the river both upstream and downstream. The impounded waters have drowned over a hundred miles of ecologically valuable riparian habitat, and although there are no dams in the Grand Canyon, the ecology of the Canyon has also been severely altered. Its riverine and riparian ecosystems have been decimated; native fish are all but obliterated both above the dam, where the deep-water lake is unsuitable, and in the Grand Canyon, where historically silt-laden warm water has been replaced by cold clear water. The dam stops natural sediment causing the loss both of canyon beaches and of backwaters critical to native fish. Even the physical geology is affected. The river has become a stream that can barely continue carving the Grand Canyon. The once powerful springtime flows are no longer large enough to clear out boulders washed into the riverbed, and the beaches are choked with exotic plants that withstand the now tepid flows. The Grand Canyon Protection Act (GCPA) was passed by Congress in 1992. That act required Reclamation to complete an Environmental Impact Statement (EIS) on the operations of the Glen Canyon Dam. Environmental studies were already in progress when the GCPA was passed. As a result of the assessment, the Record of Decision (October, 1996) required the dam to be reoperated to reduce the impact of utilizing the dam to produce "peaking" power. Management of Glen Canyon Dam to meet environmental objectives is now one of the stated goals of the Annual Operating Plan (AOP). Another result of the EIS was the formation of an Adaptive Management Working Group (AMWG) which is in charge of ongoing experiments and modifying the reoperations. The AMWG's mission is to advise on "how best to protect, mitigate adverse impacts to, and improve the integrity of the Colorado River ecosystem affected by Glen Canyon Dam." Still at issue is whether monitoring and experiments in the reservoir itself are included in the scope of the AMWG. Reoperation of the dam is now considered a part of the "law of the river." The Central Utah Project, authorized in 1956 as part of the Colorado River Storage Project Act, is the major vehicle for Utah's use of its Colorado River allotment. Final authorization did not come until 1992 with the passage of the Central Utah Project completion Act (CUPCA). Most of the CUP's subunits capture Colorado River water from the Duchesne River and tributaries in the Uintah Basin. The largest of these subunits - the unfinished Bonneville Unit - is a transbasin diversion that is designed to develop 101,900 af of water from ten Uintah Basin streams and transport the water out of the basin to the Wasatch Front through Strawberry Reservoir. With the CUP and other diversions on the Price, San Rafael, Dirty Devil, Escalante, and San Juan rivers, Utah is now using more than 60% of its Colorado River allotment. The Utah Division of Water Resources projects that this will increase to 80% by 2020 and to 93% by 2050. These optimistic projections, from the state's point of view, are not universally accepted, even among Utah officials. The CUP, which is nearing completion, continues to face logistic, administrative, and, possibly, funding problems that may not lead to as much water development as originally planned. The Uintah and Upalco units, which were intended to meet obligations to the Ute tribe and to provide irrigation water to secondary irrigators, are now dead, barring further Congressional action. The major irrigation component of the Bonneville Unit is facing increased skepticism; this water will most probably be developed for either irrigation or for municipal and industrial usage. Public officials in the Uinta Basin have recently been arguing that some of this water should remain in the Basin. Although not a part of the CUP, an emerging issue of concern is the plan to pump water from Lake Powell for municipal use in the rapidly growing area around St. George, Utah. The proposed pipeline would, as planned, provide 70,000 af/yr to the St. George area. It is extremely unlikely that the Washington County Conservancy District, which serves the St. George area, will ever receive additional water rights in the Virgin River, but the District is to begin construction of a new 50,000 af off-stream reservoir, Sand Hollow, in summer, 2001. This reservoir will supplement the existing 40,000 af Quail Creek Reservoir and ensure that the District will be able to use its full current authorization. The CAP was completed 5 years ago. The Project includes an aqueduct to transport 1.6 maf/yr of Arizona's Compact allocation to Phoenix and Tucson. Since groundwater withdrawals have drawn down the aquifer under the Sonoran Desert by over 100 feet and are unsustainable, it is hoped that the use of CAP water can replace groundwater use. The CAP went so far over-budget that the water is too expensive for agricultural use. Many of the irrigation districts, which committed to contract CAP water, have had to declare bankruptcy to renege on those contracts. The citizens of Tucson have voted to reject the use of CAP water for direct municipal use because of the high salt content of the Colorado River water. Tucson is now using CAP water in an attempt to recharge depleted groundwater. The Bureau of Reclamation has prepared a rule to help the Lower Basin states facilitate water banking and marketing. Although water marketing between the Upper and Lower Basins is prohibited by the Compact, the Secretary of Interior, as watermaster for the Lower Basin, has approved water marketing among the Lower Basin states. This rule permits the conjunctive use of surface water and groundwater. The idea behind conjunctive use is to store unused surface water underground and then pump it when needed. Plans are to allow this pumped groundwater to be used intra or interstate. The history of extended variations in the hydrologic cycle casts considerable doubt on the long-term sustainability of water banking as a solution for periods of limited surface water supply. Another use of CAP water is to settle Indian water rights claims. Under the Winters Doctrine, established in 1908 in Winters v. United States, Native Americans have water rights based on designation of their lands as reservations. The essence of the doctrine is that when the Federal government reserves land, water rights to effect the intent of the reservation are implicit. At the time its reservation is created, a tribe is entitled to water rights for "practicable irrigable acres." The administration of these federal reserved water rights through state water law has led to additional litigation in the West. Many of these claims have yet to be settled and have a priority date senior to those of most other water rights. Since much of the CAP water is still uncontracted, the Department of Interior hopes to use this water to settle tribal claims without interrupting current water use. It is likely that the tribes will lease much of their water back to historic or future non-Indian users for municipal and agricultural purposes. Ten Native American Indian Tribes have reservations in the Colorado River Basin. Tribal Rights are generally senior rights. How tribal rights are integrated into Colorado River water management and the current allocation scheme is of great importance with uncertain consequences. At this time, it appears most likely that many tribes will mesh their rights into the current allocation scheme in return for payment, either in cash or in kind. The various tribal water rights are briefly summarized below. Northern Ute Tribe - Congress has yet to take action on the Ute Indian Water Rights Settlement, which contains a quantification of the Tribe's water rights. Approximately 480,000 acre-feet of water are held in trust by the United States for the benefit of the Tribe and others within the Reservation. Depletions are limited to a total of 248,943 acre-feet per annum. The primary priority date for the Tribe's water rights is October 3, 1861, and a limited number of tribal rights have a priority of January 5, 1882. Marketing of the Northern Ute Tribes' reserved water rights outside the State of Utah must comply with the rules applicable to non-Indians who sell their water out-of-state. Southern Ute Indian Tribe - Effective December 19, 1991, the Southern Ute Indian Tribe has settled its water rights pursuant to agreement with the State of Colorado and pursuant to 1988 federal legislation. That agreement provides the Tribe with a variety of direct flow rights with priorities ranging from 1868 to 1976 in streams and rivers passing through the Reservation, and 29,900 acre feet of storage in the Animas-La Plata Project, with a project priority of not later than 1966. Ute Mountain Ute Indian Tribe - This Tribe, like the Southern Ute Tribe, has, as of December 19, 1991, a vested water right pursuant to agreement and federal legislation. The Tribe has direct flow rights in three streams on the Reservation, with priorities ranging from 1868 to 1985, and 25,180 acre feet of storage in the Dolores Project, with a project priority of not later than 1963, as well as 29,900 acre feet of storage in the Animas-La Plata Project, with a project priority of not later than 1966. Marketing both Colorado Ute Tribes' reserved water rights outside the State of Colorado requires compliance with other laws applicable to non-Indians who sell water out-of-state. Jicarilla Apache Tribe - This Tribe completed a water rights settlement, ratified in 1999, which will provide it with 40,000 acre-feet, mostly from Navajo Reservoir, with a project priority of 1957. Navajo Nation - This Tribe is in the process of quantifying portions of its water rights within the Colorado River System. The Navajo Nation already possesses a statutory right to 508,000 acre-feet for the Navajo Indian Irrigation Project from Navajo Reservoir with a project priority not later than October 16, 1957. Colorado River Indian Tribes - The Tribes have decreed water rights as a result of Arizona v. California. Those rights total 717,148 acre feet, as follows: 358,400 acre feet in Arizona with a priority of March 3, 1865; 252,016 acre feet in Arizona, and 10,745 acre feet in California, both with a priority of November 22, 1873; 51,986 acre feet in Arizona, and 40,241 acre feet in California, both with a priority of November 16, 1874; and 3,760 acre feet of water in California, with a priority of May 15, 1876. Moreover, the Tribes are currently litigating in Arizona v. California additional water rights in California, with priorities of November 16, 1874 and May 15, 1876. Chemehuevi Indian Tribe - This Tribe was awarded 11,340 acre-feet in California, with a priority of February 2, 1907, in Arizona v. California. Ft. Mojave Indian Tribe - This Tribe was awarded rights in Arizona v. California as follows: 27,969 acre feet in Arizona, with a priority of September 18, 1890; and 75,566 acre feet in Arizona, with a priority of February 2, 1911. In addition, the Tribe has 13,698 acre-feet in California, with an 1890 priority, and 12,534 acre-feet in Nevada, with an 1890 priority. Quechan Indian Tribe - This Tribe received, in Arizona v. California, 51,616 acre feet in California, with a priority of January 9, 1884. This Tribe is currently engaged in litigation in Arizona v. California to acquire additional water rights in California. Cocopah Indian Tribe - This Tribe was decreed 2,744 acre feet in California, with a priority of September 27, 1917, in Arizona v. California. The Colorado River Delta historically covered 2.5 million hectares (9,650 square miles or slightly more than the combined area of Massachusetts and Rhode Island) in the United States and Mexico. The Delta contained vast areas of woodland, wetlands, and desert habitat, each of which fluctuated in response to the annual flows in the river and provided extraordinarily rich and varied ecological habitats in the midst of desert. In the United States, the Delta included the Imperial Valley, Yuma Valley, and the Salton Sink (now the Salton Sea). Both the Imperial Valley and the Yuma Valley have become major agricultural areas as diversion and damming of the Colorado have made the desert bloom while depleting the river so that it rarely flows all the way through the Delta to the Sea of Cortez. Below Morelos Dam at the U.S.-Mexican border, the United States must provide by treaty 1.5 maf/yr to Mexico. Mexican urban and agricultural areas use the entire allotment, which, in conjunction with U.S. depletions, removes all the water from the river before it reaches the sea. Several small but valuable wetlands including La Cienega de Santa Clara (12,000 acres), Rio Hardy, and the newly-formed El Indio dot the Delta in Mexico (4,5). The portion of the Delta in Mexico has shown itself to be highly resilient and to have significant capacity to return to a far more natural state if water is available. In the early 1980's, following the completion of the Glen Canyon Dam, the Colorado River flows in Mexico increased to a level that was a significant percentage of historical annual flows and resulted in the establishment of 150,000 acres of vegetation along the river. Since that time, flows along the river have generally been negligible until 2 maf coursed through the channel during 1997 and 1998 as a consequence of El Niņo precipitation. The flows in 1997 and 1998 were sufficient to wet the entire Delta and new vegetation, both salt cedar and native species, has appeared. The Mexican portion of the Delta includes a United Nations Biosphere Reserve in its southern portion, and although the vast area from the river to the Biosphere Reserve is not included, Mexican government agencies are currently attempting to have that region added to the Reserve. Informed estimates are that annual flows through the Colorado in Mexico to the Sea of Cortez of 32,000 af/yr with 260,000 af every fourth year plus the occasional El Niņo flows are the minimum amounts necessary to reclaim much of this ecologically important area. It is worth noting that the burst of flow as a consequence of the '97-'98 El Niņo was apparently sufficient to increase the shrimp harvest in the Sea of Cortez (6). The Salton Sea was created as a consequence of an engineering error that filled the Salton Sink, a salt-covered depression in the U. S. portion of the Delta, with water. The Salton Sea has since become, along with the remnant Delta wetlands in Mexico, an important stopover along the Pacific Flyway. Only six percent of the inflow to the Salton Sea is natural flow, the rest being agricultural and municipal wastewater. The wastewater inflow sources provide enormous amounts of nutrients, which has allowed the stocked marine fish populations to thrive while simultaneously causing eutrophication. There are periodic, massive fish die-offs, the most recent estimated at between 7,000,000 and 8,000,000 in 1999, and periodic outbreaks of disease among the waterfowl. The U.S. government is currently studying the feasibility of stabilizing the Salton Sea as an ecologically sound, if manmade, condition. A comprehensive study, entitled "Haven or Hazard: the Ecology and Future of the Salton Sea," (7) has recently been published by the Pacific Institute. One of the recommendations offered by this report is, "Any restoration plan for the Salton Sea must be compatible with protection and restoration of the Colorado River Delta, Upper Gulf of California, and other ecosystems in the region." Continuing Water Development Issues There are a number of proposals, both already authorized and new projects, to develop Colorado River water. These projects include both in-basin depletions and transbasin diversions. In-basin depletions subtract water from the watershed for consumptive use. When such depletions amount to a significant fraction of the available water, the environmental consequences are often severe. Transbasin diversions, which are common in the western United States, have a multiplier effect that typically leads to exacerbation of the initial environmental damage. Transbasin diversions not only grossly alter the environment of both the donor and recipient basins, but also become active agents of social engineering in that they force newcomers, particularly in water-limited areas such as the southwestern U.S., to concentrate where the water now is. Some of the consequences of these projects include: the disruption of the natural rhythms of seasonal flows that most fish species and other wildlife rely on for reproductive triggers; reduction of the flows needed to transport sediment, sometimes even drying up rivers; loss of dilution flows from snowmelt in the headwaters to counter-balance pollutants; irrigation of unsuitable soils which causes polluted runoff; severe decreases or total lack of riparian area flooding needed to maintain habitat and refugia; and obstacles to migration of aquatic species, which dramatically reduces their range and cuts them off from needed habitat. Listed and described below are some of the current proposals for further development of Colorado River water. With Utah still occupied with implementation of the Central Utah Project, Arizona still attempting to financially digest the Central Arizona Project, Nevada pleading to be allowed to take more Colorado River water, and California working to reduce its water consumption, most of these projects are, by default, in Colorado. There are 17 transmountain diversions on tributaries of the mainstem of the Colorado River within Colorado. The Front Range of Colorado, the major urban centers on the eastern slope of the Rockies, is hoping to develop what is left of its Colorado River Compact allocation by expanding the use of existing diversions. Precise data to determine how much Colorado River water is actually being depleted in Colorado is currently being gathered. Estimates of unused Compact water range from 250,000 af to 750,000 af. The biggest obstacle to developing more Compact water is the listing of endangered fish and their Recovery Program. Another obstacle is a state law that requires "compensatory" storage for the basin of origin for any transbasin diversions. This means that twice as much water would have to be developed as intended for a diversion to comply with the law. The best known of these proposed diversions, the Animas/La Plata Project, in its present incarnation, ALP Ultralight, is no longer a transbasin diversion. The Animas/ La Plata Project (ALP) has gone through many configurations over the past 40 years. The Sierra Club has actively opposed this project, with the help of Earth Justice Legal Defense Fund, for more than 10 years. The original proposal would have pumped water, in two stages, over 1000 feet uphill to supplement irrigation in the La Plata River Basin. Two-thirds of this water would have supplied anglo farmers and ranchers, who would have had to pay only as much as they could afford, without regard to cost. Settlement of water rights claims by the Southern Ute and Ute Mountain Ute Tribes would have accounted for the other one-third of this project but with no distribution system to get the water to the tribes' reservations. The most recent proposal, referred to as ALP Ultralight, would pump 57,100 af/yr of water 500 feet uphill and store it in a 120,000 af reservoir in Ridges Basin only to let it flow back down without any proposed beneficial use other than to settle the Ute Indian water right claims. What was originally proposed as an irrigation project is now being proposed as a municipal and industrial water supply project with 3/4 of the water going to the Tribes and the rest allocated to municipalities in southwest Colorado and northwest New Mexico. The Tribes are claiming their percentage of the project should be non-reimbursable. Colorado will pay for a recreational component. The cities want to prepay for their share so they don't have to hold an election to ratify a new repayment contract. Reclamation has prepared a new Supplemental EIS, studying five structural and five non-structural alternatives, and there is Federal legislation to modify the 1988 authorization to conform to the scaled-down project. Homestake II is a new diversion proposed for the Holy Cross Wilderness Area that would take water from the Eagle River to the Arkansas River to supply Colorado Springs' future growth. This proposal has been obstructed by Eagle County's refusal to issue a land use permit. The argument was taken all the way to the U.S. Supreme Court with Eagle County prevailing. Since Colorado Springs has a vested water right, the parties are now negotiating for a smaller project that would not originate in the wilderness area. Although this project does not take water across the Continental Divide, the Uncompahgre Project is a transbasin diversion, taking water from the Gunnison River to supplement irrigation in the Uncompahgre River Valley before flowing back into the Gunnison River. This Bureau of Reclamation Project was expanded in the 1960's when project water was used to irrigate 12,000 new acres by reclassifying the soils from Class 6 to Class 3. (Class 6 soils are considered unsuitable for irrigation.) The mancos shale soils found in the Uncompahgre and Grand Valley around Grand Junction contain high levels of salt and selenium which leach into the rivers through return flows from flood irrigation. High levels of salt and selenium are a major water quality problem in the West. The Uncompahgre Valley Water Users want to expand the project by enlarging the AB Lateral to produce wintertime hydropower. Another transbasin project, the Union Park Project, has been proposed from the headwaters of the Gunnison River. This proposal includes a 900,000 af reservoir that would divert 100,000 af/yr to the suburbs of Denver in Arapahoe County. The water rights application, first filed in 1986, has been stymied by Arapahoe County's inability to show adequate water availability for this project. The results of the second water court trial are currently being appealed to the Colorado Supreme Court. The Arapahoe County Water Authority is likely to refocus its energies and concentrate on acquiring water from Blue Mesa Reservoir. Due to the tremendous cost of water court litigation, the Colorado legislature commissioned a Metropolitan Water Supply Investigation study to determine whether the Front Range could meet its future needs through a more creative use of existing supplies. This four-year study has recently been released and offers hope that future demand for water on the Front Range of Colorado can be met without the need to build more projects on the Western Slope of the continental divide. The Sierra Club should emphasize this study in its campaign to resist more water development. In Utah, the Gooseberry Narrows Project, which includes a dam, reservoir, and pipeline, in the Price River drainage, is a transbasin diversion that would aid farm irrigation in San Pete County but jeopardize municipal water supply and fisheries in Carbon County. The lower Price River, which would be degraded by this project, is considered potentially valuable habitat for several Colorado River endangered fish species. The Sierra Club, along with many other environmental and outdoor sports groups in Utah, as well as Carbon County, vehemently opposes the Gooseberry Narrows Project. In New Mexico, the San Juan-Chama project diverts approximately 110,000 af/yr from the San Juan basin into the Rio Grande basin, primarily to serve the city of Albuquerque. (a) Lee Ferry is defined in the Colorado River Compact as "a point in the main stream of the Colorado River one mile below the mouth of the Paria River." Lees Ferry (sometimes Lee’s Ferry) denotes the site of a USGS gage approximately one-quarter mile above the mouth of the Paria and, now, just downstream of Glen Canyon Dam. (1) Pontius, D. 1997. Report to the Western Water Policy Review Advisory Commission. National Technical Information Service, Springfield, VA. (2) Myers, T. 1998. Sediment Hydrology on the Colorado River, The Impacts of Draining Lake Powell. Prepared for the Glen Canyon Institute, Salt Lake City, UT. (3) Andrews, E.A. 1991. Sediment transport in the Colorado River basin. in Colorado River Ecology and Dam Management: Proceedings of a Symposium, May 24-25, Santa Fe, NM. pp. 54-75, National Academy Press, Washington, DC. (4) Zengel, S., Meretsky, V., Glenn, E., Felger, R., and D. Ortiz. 1995. Cienega de Santa Clara, a remnant wetland in the Rio Colorado delta (Mexico): vegetation distribution and the effects of water flow reduction. Ecological Engineering 4: 19-36. (5) Glenn, E., Garcia, J., Tanner, R., Congdon, C., and D. Luecke. 1999. Status of wetlands supported by agricultural drainage water in the Colorado River Delta, Mexico. Hortscience 34: 16-21. (6) Galindo-Bect, M., Glenn, E., Page, H., Fitzsimmons, K., Galindo-Bect, L., Hernandez-Ayon, J., Petty, R., Garcia-Hernandez, J., and D. Moore. 2000. Penaeid shrimp landings in the upper Gulf of California in relation to Colorado River freshwater discharge. Fisheries Bulletin 98: 222-225. (7) Cohen, M.J., Morrison, J.I., and E.P. Glenn. 1999. "Haven or Hazard: the Ecology and Future of the Salton Sea". Pacific Institute for Studies in Development, Environment, and Security. Oakland, CA. Photo: Confluence of Green River and Colorado River, Canyonlands National Park, UT. Copyright Stephen Trimble. Report Main | Background
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