232 CONSERVATION OF GROUND WATER 



voirs goes far beyond their use in development of wells that 

 draw from those reservoirs. Because ground water constitutes 

 one phase of the hydrologic cycle, a knowledge of it is impor- 

 tant in the development of all water resources, as well as in the 

 effective use of the land to take maximum advantage of the 

 water that falls as precipitation. Conversely, an adequate 

 knowledge of the ground-water phase of the hydrologic cycle 

 requires much data concerning precipitation, infiltration, soil 

 moisture, evapotranspiration, and stream flow, as well as the 

 characteristics of aquifers. 



A task force of the Hoover Commission, 1 in reporting on 

 the weaknesses of the present system of water-resource devel- 

 opment, gave first place to the "Deficiencies in Hydrologic 

 Data" and remarked that "our greatest shortcoming has been 

 the failure to provide for the utilization of rain gages, snow 

 surveys, stream-flow measurements, evaporation stations, run- 

 off and erosion studies, oround-water observation wells, water- 

 quality analyses, and other established methods of obtaining 

 data essential to the planning and construction of river devel- 

 opment projects." As a first step in overcoming this deficiency, 

 the Hydrologic Subcommittee of the Federal Interagency 

 River Basin Committee called a series of regional conferences 

 in 1949 to ascertain from technical men in the field the places 

 where additional basic data were most urgently needed. The 

 recommendations from these conferences were predominantly 

 for additional stations to measure the two phases of the hydro- 

 logic cycle that we already know most about — precipitation 

 and stream flow — and it is quite evident that no phase of the 

 hydrologic cycle is yet considered to be inventoried adequately 

 on a national scale. 



Although basic data are the foundation upon which must 

 be based the design and operation of all structures for the 

 conservation and utilization of water resources, those data are 

 valueless without adequate techniques for interpreting and 



i "U.S. Commission on Organization of the Executive Branch of the Govern- 

 ment, Organization anci Policy in the Field of Natural Resources," Task Force 

 Rept., Appendix L, U.S. Government Printing Office, pp. 18-20, 1949. 



