LETTER OF TRANSMITTAL TECHNICAL ADVISORY COMMITTEE FOR THE COMMITTEE ON WATER FLOW, Subject: Report on the Pacific region. To: The President's Committee on Water Flow. 1. The technical advisory committee for the Pacific region submits the attached report covering comprehensive plans for 10 projects in the Pacific region. THE PACIFIC REGION REPORT OF THE REGIONAL TECHNICAL ADVISORY SUB-COMMITTEE The technical advisory subcommittee for the Pacific region submits the following draft of a comprehensive plan for the most effective improvement and coordinated development of the water resources in the Pacific region in the interest of domestic water supply, irrigation, flood control, navigation, and development of hydroelectric energy. Other related matters such as watershed management, soil erosion, reforestation, and research also are discussed. The report is in 11 sections. The introduction is a general discussion of the region as a whole and the following sections cover the 10 areas selected as the most important in the order of priority as listed below: 1. Sacramento and San Joaquin 6. Snake 2. Colorado 3. Puget Sound 4. Columbia 5. Utah Lake 7. Los Angeles and San Gabriel 8. Willamette 9. Gila 10. Santa Ana The subcommittee recommends that upon the selection of one or more watersheds of the Pacific region a planning board be set up from the Departments of War, Interior, and Agriculture to prepare a detailed working plan for the comprehensive development of that stream or streams. This will afford opportunity for all departments to assemble and present in detail existing data and call attention to those data that are incomplete or entirely lacking. The subcommittee further recommends that such board be authorized to collect data and prepare plans for the development of all the a eas considered in this report. INTRODUCTION 1. General description. The Pacific region or zone, as used in this report, comprises that portion of the United States, lying west of the Continental Divide. It includes all portions of Washington, Oregon, California, Nevada, Arizona, Idaho, Utah, and portions of Wyoming, Montana, New Mexico, and Colorado. (See accompanying map.) It has an area of 846,000 square miles, or 28 percent of the entire country. 2. The population of the 7 States wholly within the region, according to the 1930 census, is approximately 9,674,000, of which 3,559,000 are rural. The largest cities-Los Angeles, San Francisco, Portland, and Seattle are on the Pacific coast. Important centers of population located in the interior are Butte, Spokane, Boise, Salt Lake, and Phoenix. 3. The agricultural products from irrigated lands of the Pacific region in 1929 were valued at about $750,000,000, while all minerals including petroleum were about $825,000,000. Range livestock use the greater part of the area and production of beef, lamb, and wool support many communities. Manufacturing is by far the largest industry, having contributed for 1929 in excess of 2 billion dollars. 4. Lumbering is an important industry of California, Oregon, Washington, northern Idaho, and locally in other parts. Redwood predominates on the California coast, with fir, pine, and cedar in other localities. 5. In general hydroelectric development in the Pacific region seems ample for present and immediately prospective requirements when the Federal developments at Boulder Canyon on the Colorado, and Bonneville and Grand Coulee on the Columbia are included. The per capita consumption of electricity is rapidly increasing in this area. 6. The Pacific has some of the best harbors in the world. The Pacific region has a large and growing foreign trade, especially with the Orient and South America. Large quantities of agricultural products are disposed of in this way while considerable quantities of fruits have been shipped to Europe. 7. The principal streams are the Columbia, Sacramento, San Joaquin, and the Colorado. These and other rivers have their sources in the thousands of miles of mountain ranges which roughly run parallel to the Pacific coast. Storms usually running southeastward over these ranges leave less water for each succeeding valley. The rainfall, which totals 100 inches annually along the northwest coast in Washington, declines rapidly to the southeast until in very large areas of the interior the average is less than 10 inches per year, and in the hottest and driest parts little or no rain falls in many years. Around Puget Sound and along the ocean shore south to San Francisco, summer rainfall is usually adequate for agriculture. In the valley of the Willamette and Columbia Rivers from Puget Sound southward lying between the Coast and Cascade Ranges, summer rains are not always adequate and agitation for irrigation recurs with every subnormal year, but insufficient progress has been made in providing water. 8. Importance of water.-To the east of the Cascade Mountains in Washington and Oregon and to the east of the Coast Range in California our study of the water resources of the Pacific region shows that its dominant feature is aridity. Over the greater part of this area a scanty and uncertain rainfall makes irrigation necessary to the successful production of crops. This involves at present and in the future the consumptive use of rivers. Here, as in all arid lands, civilization follows the banks of streams. The present interior centers of population are dependent for their continued prosperity on the ability to use water in irrigation, and the manner in which the floods of streams are stored and water diverted and used will largely control the location of future centers of population and industry. 9. Another important fact which had to be recognized in making these plans is that the changes in the character of these rivers as a result of increased consumptive use will be far-reaching. It creates problems of a different character to those involved in the improvement of streams of humid sections. In the humid sections there is a surplus of water. Rivers are valuable because they provide for its |