A survey of chemical and bacteriological water quality in the Grand Canyon was undertaken to assess possible health hazards to river travelers. The water quality of the main Colorado River channel is relatively stable with only slight increases in ionic concentration and bacteriological load with respect to distance from Lee Ferry and time over the summer season. The tributary streams show extreme temporal variability in chemical water quality and bacteriological contamination as a result of the summer rain and flood patterns in the tributary canyons. These side streams pose a definite health hazard to unwary river travelers. More extensive sampling is called for to determine the sources of this contamination and to protect the quality of the Grand Canyon experience.

From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / The Lake Powell Research Project is investigating the effects of man's activities on the Southeastern Utah-Northeastern Arizona region. A major portion of this project is devoted to the hydrology of Lake Powell, the largest recent modification in the region. This hydrologic research is separated into the following subprojects and administrative institutions: Subprojects: Streamflow Trends, Evaporation, Bank Storage / Institution: University of California at Los Angeles. Subprojects: Sedimentation, Physical Limnology, Lake Geochemistry / Institution: Dartmouth College. The project is now concluding its first year of full-scale research effort. The UCLA subprojects are aimed at developing an overall water budget for the lake, both on an annual and long -term basis. The Streamflow_trends study indicates that the Upper Colorado River Basin (UCRB) has shifted from a few extraordinarily wet decades in the early 1900's to several relatively dry decades up to the present. Evaporation efforts so far are toward installing a data collection system capable of furnishing data for mass-transfer and energy-budget calculations. The bank-storage study indicates that bank storage constitutes a large fraction of the impounded waters. Secondary as well as primary permeability may be of major importance in bank storage. The Evaporation and Bank Storage subprojects are working in close coordination with the Bureau of Reclamation. The Sedimentation subproject has shown that the rate may be in general agreement with earlier estimates from river flow and suspended sediment data. However, the distribution is affected by sediment dams formed by slumping of canyon wall material. Physical limnology studies indicate the presence of stratifications resulting from thermal and turbidity layers causing complex movements within the lake waters. Field and laboratory efforts in lake geochemical analyses indicate that the precipitation of calcium carbonate may be the most important chemical process in changing the water quality of the lake.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / From the establishment of the Arizona resources board in 1928 until the Arizona Water Commission was formed in 1971, no state water plan was developed. Since 1971, the longest and most intensive planning studies have been concerned with allocation of Colorado River water through the central Arizona project. Future plans involve desalting sea water, weather modification, importation of water, etc. The Arizona state water plan ultimately will be a plan of management of Arizona's limited water resources. Water plans and economic and environmental impact evaluations are scheduled for completion by july, 1977.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The 2 major environmental problems of Arizona and the southwest are the alkalinization of soil and water by irrigation and air pollution from copper smelting. It is proposed that the amelioration of both problems may be solved through a common process. This is the production of sulfuric acid from sulfur dioxide, which is the main pollutant of smelter effluent gases. The conversion process is cheap and easy, and the sulfuric acid could then be added to irrigation waters to increase the solubility of CA carbonate in the soil, thereby decreasing alkalinity. Lower alkalinity results in increased soil permeability and increased water use efficiency by plants. The potential market for sulfuric acid in irrigation was calculated, on the basis of neutralizing 90% of the bicarbonate ion concentration in Colorado River water and Arizona well water, to be about 1.6 million tons annually, representing about 1/3 of the sulfur now dissipated by smelters as air pollution. This market includes both the Imperial Valley of California and the Mexicali Valley of Mexico, both of which are currently experiencing mounting salinity problems. Salinity itself is not amenable to this treatment, but the cumulative increase in NA and bicarbonate may be slowed and reversed, leading to gradual soil stabilization.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / A proposed desalting plant is an engineering solution to the effects of a problem which could have been avoided and even now could be reduced on the farm. Water costing $125 per acre-foot will be delivered to Mexico to grow wheat, cotton, garden crops, alfalfa and safflower, of which the average value added per acre-foot was estimated at $80 for cotton and garden crops and $14 for wheat, alfalfa and safflower. The U.S. government, instead of building the desalting complex, could accomplish its purpose just as well by paying each farmer in the Yuma area, in return for the farmers reducing their drainage flow by whatever method they see fit, $114 per acre per year for the next 50 years. With proper management on the farm, the costs of managing salinity need not be high.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / The 14.6 miles of the Colorado River bounded by Parker Dam and Headgate Rock Dam has been referred to as the Parker Strip. This river reach has become a high use recreation area during the past decade with 4,000 permanent residents and as many as 120,000 water enthusiasts on long weekends. The riparian area of the river is heavily clustered with mobile homes, marinas and public beaches. The means of sewage disposal is exclusively via septic tanks. Recent surveys by the Environmental Protection Agency, Arizona State Department of Public Health and the University of Arizona have localized surface water bacteria levels that may indicate a developing groundwater problem. The geohydrology of the area indicates that the septic tanks are located in Post -Pliocene Colorado River deposits. The deposits are quite thin and relatively narrow. Since the deposits are locally derived sands and gravels, the horizontal hydraulic conductivities are such that a relatively short flow time to the river may result. Intensive evaluation of the degradation of the water quality in these deposits is needed to determine if the ground water supply was jeopardized by septic tank systems.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / This paper describes a water supply data base being developed for the Colorado River Basin States by the University of Arizona under contract with the Electric Power Research Institute, Inc. This data base is a guide to existing natural, technical, economic, and legal water data and water data agencies in the states of Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Combined urban, agricultural, industrial and mining groundwater withdrawal from the Santa Cruz River Basin exceeds natural aquifer replenishment by 74,000 acre -feet annually. Four ameliorative water management alternatives are presented singly and in combination with one another. These alternatives are importing Colorado River water, exchanging treated effluent with mining and agricultural interests for groundwater, interbasin water transfer, and retiring farmlands for groundwater rights. These management philosophies are applicable to most economically emergent urban areas in arid and semiarid regions.

The recent passage of the Swing-Johnson bill by Congress and its approval by the President has been the signal for a general rejoicing throughout the West, and especially in Southern California, the section to be meet directly benefited by this legislation. There has been a widespread feeling that the long fight for Federal development of this great western river is over, and that we may begin shortly to realize some concrete returns upon our investment. Press reports indicate that many are already seeking work on the construction of the dam at Black Canyon, in anticipation of the immediate launching of the project. · "Wild cat" employment agencies have sprung up and are extorting fees from work-seekers by promises of good positions on the construction job. Real estate "sharks" are already active and have promoted the sale of much land which they represent as being situated in a favorable spot for irrigation from water to be impounded by the dam. Much of this land is said by the government to be situated several hundred feet above the level of the proposed dam to be unfit for use even if water were available. To forestall this exploitation of men and land the government has recently issued a timely warning to the effect that it will be at least eighteen months before work on the construction of the dam is actually begun and that no homesteading claims on land under the project will be allowed until its completion which will be about eight years. !his announcement may come as somewhat of a shock to many optimists unacquainted with the actual provisions of the bill, for them it may be said that much depends upon the possibility of reaching a satisfactory solution of the problem of water allocation between California and Arizona. To date such a solution has not been reached and unless Arizona is satisfied it is highly probable that the question will be carried to the courts and long months of litigation ensue. If a satisfactory compromise is reached, the launching of the work will not be· long delayed. Of the ultimate outcome there can be no doubt, and the future seems to hold a very rich promise for the great Southwest. As this subject is approached for study one is somewhat overwhelmed by its many ramifications. The engineering problems alone are of tremendous scope. The legal aspects of the question furnish material for exhaustive study. The political issues tend to claim a greater place than their real merit would seem to justify. While all the different phases of the question are somewhat closely bound together, it has been the purpose of the writer in this study to draw at least a faint line of demarcation and confine it as much as possible to the economic aspects. The Boulder Canyon Project Act proposes a four fold plan of economic development; namely, flood-control, irrigation, power development and domestic water-supply. It is to these features that most attention will be given, together with the historical background of the program. It would be only just at this point to acknowledge the very generous response to calls sent out by the writer for reference material. More than a score of individuals and organizations responded with most gratifying results. Included in these were the governors of the seven states in the Colorado River basin, Senator Hiram W. Johnson and Congressman Philip Swing of California, co-authors of the Swing-Johnson bill; the Chairmen of the Senate and House committees on Irrigation and Reclamation; the Pacific Gas and Electric Company; the Southern California Edison Company; the Boulder Dam Association, and many others.