No. FIGURES 1. The amount of water consumed is one of the most important problems of water use. Water that is evaporated or is incorporated in a prod- uct is consumed. Irrigation accounts for 80 to 90 percent of all water consumed. (Courtesy of U.S. Geological Survey) - 2. Total demand for water and proportion required for agricultural use Butyl-covered nylon bag assembly, with ground cover in background. Bag has a capacity of 1,600 gallons, which can be filled with approxi- mately 1 inch of rain on the ground cover__. 4. Layout for collection of water from a ground cover installation. The 8. Laying out 15-gage butyl lining during construction. The lining will be buried and covered with earth material for protection.... 9. Asphalt-coated jute liner on a farm irrigation canal 10. Thirty-six-inch diameter lay-flat tubing used to convey water over perforated semirigid vinyl plastic sheeting-is on flat spool shown on top of plow. The edges are die-cut so they can be "zipped up" as sheet is formed into liner... 13. Jute netting on steep road bank to assist in establishing vegetative mulch is held in place with paper netting, which is never removed. 15. Fine mesh jute thatching in experimental waterway after a test flow. The jute strands are approximately one-fourth inch in diameter... 1. Total irrigation water requirements for Eastern and for Western United States for 1954, and that estimated for 1980 and 2000 2. Growth of saltcedar infestation in New Mexico__ 3. Losses from weeds in western irrigation systems, 1957- 4. Cost of developing water by means of ground covers. 5. Yields of wheat on benches with various contributing areas, 1959–61. 6. Effect of plastic sheet cover on evaporation losses, total water use, crop yield, and water use efficiency, North Platte, Nebr., 1958-59. 7. Surface films to stabilize silty clay soil on 3:1 slope against erosion by water. Treated March 27 to April 7, 1961. Treatments are listed 56 NEW MATERIALS AND METHODS FOR WATER RESOURCE MANAGEMENT A Report to the Committee on Public Works, U.S. Senate, May 1962 INTRODUCTION This report was prepared as a result of committee resolution of the Committee on Public Works, U.S. Senate. By unanimous vote, it was resolved that the committee shall institute a study and investigation of new materials, use of new materials and new designs, and methods that may be adapted in flood control and rivers and harbors, roads and highways, public buildings, water pollution control, waterpower and other development, utilization, preservation and protection projects, and that a committee report shall be prepared thereon and submitted to the Senate. The report herein describes the research being carried on throughout the United States by the Soil and Water Conservation Research Division, Agricultural Research Service, on new materials, equipment, and methods for soil and water conservation. Those parts of the report dealing with the use of chemicals in the control and management of aquatic weeds, brush, and phreatophytes were prepared by the Crops Protection Branch of the Crops Research Division. Throughout the report it will be noted the terms "uneconomical," "unsatisfactory," "needs further study," etc., are used. These are not to be construed as being final or that the materials discussed are to be no longer considered in water conservation. Sufficient results have been developed through research to show that the potential of these materials is enormous and that in many cases only slight improvements or alterations of the materials stand in the way of widespread use. Procedures and methods of using new materials in the field also will require further study to assure that their widespread use will be economical. After careful analyses of present evidence it must be concluded that we are on the threshold of a widespread use of new materials in water conservation and that many practices long considered standard will be altered substantially. A very large part of the research on use of new materials in water conservation has been made possible by the cooperation of numerous industrial and commercial enterprises. Many new materials and equipment tested have been donated to various research locations. Without this cooperation the advancement now existent could not have been attained. 1 THE NATION'S WATER PROBLEM At the National Water Research Symposium held March 28-30, 1961, Washington, D.C., Hon. Orville L. Freeman, Secretary of Agriculture, stated in specific terms the overall water problem of the Nation, when he said: We are a fast-growing nation. Our national population is rising at the rate of 340 persons per hour, 8,000 per day, 3 million per year. This is a faster rate than that of any major industrial nation and faster than many underdeveloped countries. *** If the present trends continue, just 39 years from now we will have to provide for twice as many people as we now do. But the demand for water is growing even faster than population. Now in 1961 we use about 300 billion gallons of water per day. In 1980-only 19 years hencewe well require 600 billion gallons of usable water per day. That's the size of the problem. AGRICULTURAL USE Agriculture, being the greatest user of water, is directly concerned with the increasing demand for water. Irrigation now uses about 46 percent of all the water used in the United States (fig. 1).' FIGURE 1.—The amount of water consumed is one of the most important problems Water that is evaporated or is incorporated in a product is consumed. Irrigation accounts for 80 to 90 percent of all water consumed of water use. (courtesy of U.S. Geological Survey). Geological Survey, for the Select Committee on National Water Resources pursuant to S. Res. 48, 86th 1 Committee Print No. 1, "Water Resources Activities in the United States," prepared by the U.S. Further references to materials issued by the select committee will be identified simply as Cong., 1st sess. "committee print" followed by the appropriate number. U.S. GEOLOGICAL SURVEY ESTIMATES OF WATER USE Estimates by the U.S. Geological Survey 2 indicate a total withawal of water in the United States of about 1,740,000 million gallons er day during 1955. Of this amount about 1,500,000 million gallons as withdrawn for production of water power. The 240,000 million allons remaining was withdrawn for public supplies, rural use, selfupported industrial use, and irrigation. Only about a fourth of all ater withdrawn is consumed. Most of the water consumed is used or irrigation; a fact of added importance when it is considered that rigation is practiced at times and places where the water supply is kely to be inadequate. This report deals with use of water for gricultural purposes and the potential conservation practices that ill lead to a more efficient use and reduction of water loss. About 123 million acre-feet of water was used in 1955 to irrigate 34 illion acres (1,000 acre-feet per year equals 0.89 million gallons er day). Of this amount 91 million acre-feet was delivered to farms nd 32 million acre-feet was lost in conveyance. Generally, not more han 60 percent of the water delivered at the farm headgate is conumed by crops.3 Therefore, of the total amount of water use charged o irrigation only about 45 percent goes into crop production. Almost 0 percent of the water withdrawn for irrigation in the United States used for irrigation in the 17 Western States where rainfall is inadeuate for profitable crop production and evaporation losses, evaporanspiration rates of nonbeneficial plants, and seepage losses are high. However, irrigation is increasing in the Eastern States (table 1). TABLE 1.-Total irrigation water requirements for Eastern and for Western United States for 1954, and that estimated for 1980 and 2000 1 From Committee Print No. 12 (p. 19). Based on medium population level projections. Nathaniel Wollman reported agriculture will require an average daily withdrawal of 184,000 million gallons of water per day in the year 2000 (fig. 2). WATER LOSSES The opportunities to improve and conserve irrigation water supplies These can best be evaluated by consideration of the various losses now occurring. are many. MacKichan, K. A. "Estimated Use of Water in the United States, 1955." U.S. Geological Survey Circular 398. Blaney, H. F. "Climate as an Index of Irrigation Needs." In Water, U.S. Department of Agriculture Yearbook 1955, pp. 341-355. |