Basin for irrigation in adjoining basins. The Strawberry Valley project was diverting water from Strawberry River, a tributary of Duchesne River, to Spanish Fork in the Bonneville Basin in Utah. Several other small diversions were being made into the South Platte and Arkansas watersheds in Colorado. Additional large diversions, amounting to over 400,000 acre-feet, were being considered for development in these States, including transmountain diversions for the municipal water supply of Denver.

Topography and the high cost of projects, as well as climate and lower crop values, were limiting the rate of irrigation expansion in the upper basin.

Development in the lower basin, with its climatic conditions favorable to intensive cultivation of semitropical fruits, cotton, lettuce, and melons, was being hampered by limited low-season stream flows. Irrigation on the Gila was well advanced by 1922. The Imperial Valley, which then had over 400,000 acres under irrigation by direct diversion from the Colorado River without storage regulation, suffered a water shortage in each low-water

year. The canal serving Imperial Valley lands also supplied water for the irrigation of 200,000 acres or more in Mexico, thus exporting some 3,000,000 acre-feet annually out of the basin for use in both countries.

FLOOD CONTROL

Uncontrolled the Colorado River was a natural menace. Before the construction of Boulder Dam, the lower stretches of the river were annually subject to long sustained floods from the melting snows of the high mountains in Colorado, Wyoming, and Utah. Floods originating in the lower tributaries were of shorter duration but extremely erratic and perhaps not less damaging. The tragic menace from floods, however, was not fully realized until 1905. Then the Colorado, swollen by flood waters from the Gila, broke through a cut which was made 4 miles below the international boundary by the California Development Co., operators of the Alamo Canal. For 16 months the Colorado poured its entire flow into Imperial Valley's sunny fields and flourishing communities. It enlarged the Salton Sea to a lake 76 feet deep and 488 square miles in area, and threatened permanently to engulf the entire valley. The break was finally closed with great difficulty and expense, but about 30,000 acres of arable land had been inundated, farms ruined, homes destroyed, highways washed away, and railroad tracks wrecked. Miles of mainline track of the Southern Pacific Railroad had to be moved to higher ground, and tangible damage into the millions of dollars was sustained. Here, in the need for flood control, was the prime motivating reason for the construction of Boulder Dam.

Protection of the delta lands lying principally below the level of the Colorado had required the building of levees in both United States and Mexico. Each these were year lashed by silt-laden floods. The levees were built higher and stronger. Maintenance of the levees was an expensive burden and was complicated by international problems.

Levees constructed to protect the Yuma project on the Colorado just north of the international boundary line had broken several times with disastrous local results. Another similar flood occurred in 1922 when the levees along the Palo Verde Valley in California were broken. To protect the lands on the lower river, 150 miles of levees were maintained. Although many additional breaks occurred, the major levees were intact in the early 1920's. Defensive measures, however, became more and more burdensome. From 1906 to 1924, 104 million dollars were spent by various agencies on levee construction and maintenance on the lower Colorado River, including protection for Imperial Valley. Even this large expenditure did not eliminate the menace. The continued threat of a major break from some unexpected river change still remained and 100,000 people lived in fear that the river might overwhelm them.

SILT PROBLEMS

The difficulty of maintaining an adequate levee system was aggravated by siltation. Each year the Colorado River was depositing over 100,000 acre-feet of silt in the delta region, lifting itself higher and higher and making a larger and continuous expenditure necessary to maintain levees protecting the Imperial Valley. In 1923 and 1924 the Imperian irrigation district was spending over $500,000 annually to remove silt from its canal systems. In addition, it was estimated that Imperial Valley farmers expended about $1,000,000 to repair damages from silt deposits on their farms.

HYDROELECTRIC POWER

In the early 1920's the existing hydroelectric power developments in the Colorado River Basin were largely confined to the tributaries of the Colorado River. Thirty-six plants with a combined capacity of about 37,000 kilowatts were in operation, the largest being the Shoshone plant of the Colorado Power Co. on the main stream above Glenwood Springs, Colo., and the plant built by the Bureau of Reclamation at Roosevelt Dam on the Salt River in Arizona. Each of these plants had an installed capacity of approximately 10,000 kilowatts.

In 1922 the Salt River Valley Water Users' Association started the construction of a series of three dams below Roosevelt Dam on the Salt River for irrigation storage and power production to help supply the needs of the Phoenix

area.

In the early 1920's the southern California coastal plains centering around the Los Angeles metropolitan area were experiencing a phenomenal growth, the population more than doubling from 1920 to 1930. A great potential power market thus was being created. Serious consideration was also being given to the electrification of railroads in the Colorado River Basin. Although the power uses within the basin at that time were small in the aggregate and the sparse population needed little power development for ordinary local uses, the rapidly growing market in the southern California area combined with advancement in electric power transmission had created a demand for a large amount of additional power. The growth of the power load was rapidly exhausting the available hydroelectric resources of southern California and an additional source of power was much needed for its growing industrial development.

MUNICIPAL WATER SUPPLY

With no large cities in the basin, the needs and developments for municipal water supply within the area had been small, but in the early 1920's it was becoming increasingly evident that the rapidly growing southern California metropolitan area would soon demand a new source of

water.

Los Angeles was utilizing fully its Owens Valley water and had studied other sources from which water could be obtained. The only adequate practical source appeared to be the Colorado River, whose floodwaters, if properly conserved, could be made available for such use.

The need for a source of domestic water supply became an additional and potent reason for urging the development of the Colorado River. In 1923 the first reconnaissance for an adequate route from the Colorado River to the southern California area was undertaken by the city of Los Angeles. The general feasibility of such an aqueduct was soon established, and on June 28, 1924, the city of Los Angeles made a filing with California State authorities on a flow of 1,500 second-feet of water from the Colorado River, or 675,000 gallons per minute.

Summary of Conditions in the Early 1920's

By 1920 the population of the Colorado River Basin was 634,334 persons, with the lower basin growing more rapidly than the upper basin. In the early 1920's mining was being replaced by irrigated agriculture as the leading industry in the basin. Livestock grazing was important, lumbering was a lesser industry, and the tourist trade was just starting to develop.

Several important national parks had been found in the basin, the most important being the Rocky Mountain National Park, established in 1914, and the Grand Canyon National Park established in 1919. The Fall River Road over the Continental Divide in Rocky Mountain National Park was completed in 1920. By that time health resorts and scenic attractions in the basin along the transcontinental railroads long had been enjoyed by the traveling public, but automobiles and the rapid development of a network of good highways were just beginning to make accessible generally the basin's more remote areas. Large sections of land in the basin had been set aside as Indian reservations. Over 17,000,000 acres in Arizona alone were under the jurisdiction of the Office of Indian Affairs. The Indian population, which was about 80,000 in 1920, had remained practically constant for years, but began to increase materially during the 1920's.

Livestock grazing continued to be an important industry in the basin. By 1920 control of large grazing areas by the Forest Service was stabilizing and making more profitable the livestock industry.

Irrigation development in the upper basin was considered to be lagging behind that in the lower basin, where rapid progress was being made in the Gila River Basin. Main stream developments on the lower river, however, were being impeded by lack of storage facilities; existing developments were suffering frequent shortages and, moreover, were being threatened by continued flood hazards aggravated by silt problems.

Thus by 1920 the situation with respect to the Colorado River had become very tense. Increasing upstream depletions were accompanied by increased requirements for irrigation development in California and Mexico. The constant threat of an unmanageable break of the river into Imperial Valley during flood stages was also becoming more serious with the rising level of the river and its flood plains within the levees protecting the Imperial Valley. Meanwhile the rapid growth of the metropolitan district of the southern California coastal region was creating a great demand for a large block of power and for additional municipal water supplies. Similar demands for municipal water for the growing city of Denver in the adjacent Platte River Basin were anticipated.

About the same time a keen interest in the Colorado River was displayed by various public and private agencies, seeking the right to develop hydroelectric power but proposing to provide storage and flood control incidentally.

An extensive investigation by the Bureau of Reclamation to develop ways and means of meeting all of the various needs resulted in the recommendation for the construction of a dam either in Boulder Canyon or Black Canyon for flood control, navigation improvement, irrigation storage, silt control, and power development. The long standing need for a canal wholly within the United States also was recognized and it was recommended that such a canal connecting the river at Laguna Dam with the Imperial Valley be constructed and thus eliminate all international complications.

Between the Upper and Lower Basins

FORCES ACTIVATING INTERSTATE AGREEMENT

For a number of years prior to 1922 the lower basin area, growing more rapidly in population than the upper basin, had pressed for development of the lower river and the upper basin and objected. In 1919 and again in 1920 bills were introduced in Congress for Federal assistance in building an all-American canal. In April 1922 a third bill had proposed not only the building of an all-American canal, but also the building of a storage dam on the main river below the mouth of the Green River.

It was rapidly becoming apparent that the normal flow of the Colorado River would not be adequate to supply all of the uses envisioned by the Colorado River Basin States. The proposals for storage in the lower basin without guaranties to the upper basin States were regarded by the latter as threatening to establish priorities which would preclude later use of the water in the upper basin.

The law respecting rights to the use of waters of interstate streams was not well settled. Each of the various

States claimed exclusively the right to regulate the appropriation of water within its boundaries. At the same time claims were made that the Federal Government had jurisdiction over the waters of interstate streams. It was argued that no reasonable regulation of the flow of the Colorado River by storage appeared to be feasible except with the approval and the control of some authority higher than the States and that the Federal Government logically should effect the regulation of Colorado River development. The lower part of the stream was or had been navigable and, therefore, was subject to jurisdiction by the United States. At the same time the desire prevailed to obtain Federal aid in the financing of the huge multiplepurpose development considered necessary for the utilization of the stream flow of the lower Colorado River.

Some form of an agreement between the various factions was essential before comprehensive development of the Colorado River could proceed. Each State approached the problem individually. The conception of a division of water as between the upper and lower basins, which was finally adopted, instead of an apportionment among the individual States, crystallized slowly. The common desire for a solution gained momentum and finally resulted in an interstate compact.

The lower basin States favored a compact because they wished to enlist the support of the upper basin States in securing legislation by the Congress for main stream developments which were urgently needed for further expansion in the lower basin. States in the upper basin favored a compact because they desired to feel secure in their rights to further development of water uses, believing that they would be deprived of such rights by prior appropriations and uses downstream if they did not enter into a special agreement.

The States of both areas desired to retain control of water rights within their respective boundaries and thus were willing to enter into an interstate agreement to avoid the complete Federal control of the Colorado River that otherwise possibly would result.

Another significant motivating factor leading up to the Colorado River Compact was the desire of the people in the Colorado River Basin to give agriculture priority over power in the use of water.

NEGOTIATIONS LEADING TO THE COMPACT

In 1920 at a meeting of representatives of governors of Western States, a novel proposal by Delph E. Carpenter of Colorado that the States exercise their treaty-making powers was endorsed as a means of extricating the Colorado River Basin States from their perplexing predicament. After this proposal was approved by the governors, the respective legislatures of the seven Colorado River Basin States adopted appropriate legislation authorizing the ap

Following its organization meeting and numerous executive sessions held in Washington, the Commission met for public hearings in Phoenix, Los Angeles, Salt Lake City, Grand Junction, Denver, and Cheyenne in 1922. Final sessions, held at Santa Fe during November of the same year, culminated on November 24 in the signing of the Colorado River Compact by the commissioners of each of the seven basin States and the representative of the United States. The compact, however, was subject to ratification by the legislative bodies of the States involved and by the United States.

The compact was approved during the following year (1923) by six of the seven basin States, Arizona declining. As the compact provided that it would become binding only upon approval by the legislatures of each of the signatory States and by the Congress of the United States, it became necessary for the six approving States and the United States to enact laws waiving the provision of the compact requiring approval by all seven States and providing that the compact would become effective as to approving States if six States, including California, concurred. Such legislation was enacted and in 1929 the compact became binding upon all of the basin States except Arizona by a provision of the Boulder Canyon Project Act. Arizona did not ratify the compact until February 24, 1944.

THE COLORADO RIVER COMPACT

The Colorado River Compact provides principally for a division of the available water of the Colorado River system between the "Upper Basin" and the "Lower Basin" at Lee Ferry, which is defined as a point on the Colorado River 1 mile below the mouth of Paria River. The nearest stream gage to this point on the Colorado River is at Lees Ferry, which is above the mouth of the Paria River. Lee Ferry, a few miles below the ArizonaUtah boundary, is a natural point of demarcation. Here all the waters of the entire upper system, including the Paria River and return flow from irrigation diversions, converge to form a single stream. The total stream flow

at Lee Ferry is computed by adding the flow of the Paria River to the flow of the Colorado at Lees Ferry.

The compact (art. IIIa) apportions to each of the upper and lower basins in perpetuity a total of 7,500,000 acre-feet for beneficial consumptive use annually and (art. IIIb) grants the further right to the lower basin to increase its beneficial consumptive use by 1,000,000 acrefeet annually. This division does not apportion the total annual water yield of the system, but (art. IIIc) establishes the basis for supplying any right later recognized in Mexico and (art. IIIf) leaves the apportionment of any excess among the States after October 1, 1963.

The compact also divides the basin States into two divisions: the "States of the Upper Division," including Colorado, New Mexico, Utah, and Wyoming; and the "States of the Lower Division," including Arizona, California, and Nevada. By the terms of the compact (art. IIId), the States of the Upper Division cannot cause the

flow of the Colorado River at Lee Ferry to be depleted below an aggregate of 75,000,000 acre-feet for any period of ten consecutive years. Since the State boundaries do not conform to the actual drainage basin boundaries of the upper and lower basins, two of the States of the Upper Division, New Mexico and Utah, have a part of their territory in the lower basin. Arizona, one of the States of the Lower Division, also had a part of its territory in the upper basin.

By a provision in the compact, the Colorado River Basin includes "All the drainage area of the Colorado River system and all other territory within the United States of America to which the waters of the Colorado River system shall be benficially applied." Other provisions limit the use of Colorado River water to the seven basin States. Thus the exportation of waters from the actual drainage basin to adjoining areas is authorized "if such diverted water is to be used within the boundaries of the States