234 CONSERVATION OF GROUND WATER 



water in a ground-water reservoir requires much more than 

 the water-level fluctuations in selected wells, although those 

 records are basic in the inventory. The fundamental data 

 needed before these water-level records can serve their full 

 purpose are outlined in a subsequent section. 



If the utilization of ground-water resources is to be an in- 

 tegral part of the effective development of all water resources, 

 and more broadly of all natural resources, more must be 

 achieved than the collection, interpretation, and analysis of 

 basic data concerning the separate phases of the hydrologic 

 cycle. The results of that work must be integrated to furnish 

 a quantitative inventory of the water passing through all 

 phases of the cycle. Here is a field still practically untouched. 

 A major difficulty has been the limited scope of the agricul- 

 turists, agronomists, biolosrists, chemists, engineers, foresters, 

 geologists, meteorologists, physicists, and others who are hy- 

 drologists at times and in varying degrees; in large part the 

 scope of activity of governmental agencies has been restricted 

 also by legislative authorizations or appropriations. An in- 

 creasing number of scientists have realized the need for 

 delineating the operations of the entire hydrologic cycle in a 

 drainage basin or other area of study, as a preliminary to com- 

 prehensive development, but they have been handicapped by 

 the lack of essential data, especially as to the movement and 

 storage of water beneath the land surface. As a result there has 

 been a common tendency to ignore those lesser known phases 

 of the hydrologic cycle or to guess at their meaning on the 

 basis of studies of precipitation and infiltration and stream 

 flow. 



The inadequacy of comprehensive hydrologic research has 

 long- been recognized. The National Resources Committee in 

 submitting a report on "Deficiencies in Hydrologic Research" 

 in 1939, 4 stated: 



Present information on the significance and interrelation of dif- 

 ferent phases of the hydrologic cycle contains much that is in need 



* "Deficiencies in Hydrologic Research," National Resources Planning Board, 

 Natural Resources Committee, p. v, 1940. 



