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Show EXPLORATION FOR HIDDEN GROUNDWATER RESOURCES WILL BE UNDERTAKEN THE PROGRAM MAKES FULL PROVISION FOR THE DEVELOPMENT OF THIS NEGLECTED FEATURE OF THE HYDROLOGIC CYCLE extent and conditions of developing ground- water resources for each area, independently or in connection with surface- water resources. Basic to this program is the development of the general principles and technology of ground- water hydrology, especially of the hydrologic and geologic foundation for the active management of ground- water resources. The necessary maps and research to determine the methods and possibilities of recharge of subsurface reservoirs is an important part of the program. Exploration for hidden, and at present unutilized, ground- water resources will be undertaken. This part of the program can confidently be relied on to reveal extensive resources not now utilized. IV. EVAPOTRANSPIRATION Present program.- Rates of evaporation are now determined at a small percentage of the Weather Bureau stations but only for a restricted set of conditions. Specialized studies of the consumption of water by plants under various sets of circumstances are carried on by various Federal agencies, primarily for the purpose of special programs mainly in the fields of forestry and agriculture. The determination of rates of evapotranspiration and of the amounts of water involved in the various processes of returning water to the atmosphere has not been made for any drainage basin. No basis has been established for a comparison of the rates and amounts involved in evaporation and transpiration, with the amounts involved in other phases of the hydrologic cycle. National water resources basic- data program.- The program makes full provision for the development of this neglected feature of the hydrologic cycle. The Weather Bureau, Geological Survey, and other agencies, especially the Department of Agriculture, are made responsible under the program to determine the rates and calculate the amounts of water returned to the atmosphere through evaporation from open- water surfaces, swamps, and wet ground, and the rates and amounts involved in transpiration by various types of plants, both useful and nonuseful. Of special significance will be the determination of the amounts wastefully used in superevapotranspiration mechanisms which now waste large quantities into the atmosphere. In some basins far more is dissipated uselessly than is involved in surface stream runoff or that used beneficially. Present fragmentary data will be replaced by adequate and complete data of the total quantities of water involved in these phases of the hydrologic cycle. V. INTERRELATION OF THE VARIOUS FEATURES OF THE HYDROLOGIC CYCLE Present program.- No Federal agency is made responsible for developing and interpreting the interrelation of the various phases of the hydrologic cycle. Some phases of the cycle are neglected and interrelated phases are not given adequate interpretation. Even the relationships between surface stream flow and ground- water movements are not established except in a limited number of areas. At present there is no Federal basic- data program in water resources; instead, there are fragments of a program with incomplete coverage in some phases of the hydrologic cycle and virtually complete neglect in other phases. Water, the resource on which we are now expending more funds than on all other natural resources combined, is still without adequate provisions for the determination of its amounts and the necessary conditions for its most effective utilization. 29 |