324 



CONSERVATION OF GROUND WATER 



D 



Declining water levels, significance of, 



271-272 

 Deficiencies, in hydrologic knowledge, 

 228, 281 

 in legal concepts, 243 

 Definite underground streams, 248 

 Detention storage, 179 

 Deterioration in quality (see Contam- 

 ination) 

 Diffused surface waters, 248 

 Disposal of water, inventory of, 239 



methods of, 217 

 Drainage, by ditches, 194, 197 

 by pumping, 196, 197 

 of mines, 82, 196 

 Drainage wells, 202 

 Dug wells in poorly permeable mate- 

 rials, 32 



Erosion, climatic factors in, 183 

 geologic factors in, 183 

 related to vegetal cover, 180 



Evaporation, from reservoirs, 76, 241 

 from soil, 199 



Evapotranspiration, definition of, 15 

 potential, 21 



proportion of precipitation, 216 

 relation to temperature, 172, 186 

 rights to water salvaged, 252 



Facilities for water storage, 26-27 



Fallow land, 163 



Fault barriers, 52, 56, 114 



Flood control, coordinated with arti- 

 ficial recharge, 60, 77, 274 



Flood-detention reservoirs, 226 



Floods, increased by drainage, 194 

 reduced, by forest cover, 179 



by ground-water recharge, 157, 

 226 



Fluctuations of water levels in wells, 

 index of stream flow, 237 



Fluctuations of water levels in wells, 



significance of, 271-272 



(See also Artesian pressure; Water 

 table) 

 Forest cover, 177-181 



Glacial drift aquifers, 48 

 Glacial recession, 173 

 Grass cover, 167, 184 

 Gravity, 15 



Ground water, inventory of, 235-237 

 Ground-water reservoirs, changes of 

 storage in, 32 



definition of, 28 



delineation of, 29 



fully developed, 92 



overdeveloped, 37-51 



partly developed, 77-91 



volume in storage, 28, 236 

 maintenance of constant, 273 

 Ground-water supplies, advantages 

 of, 223, 225 



disadvantages of, 224 



H 



Heat-exchange systems, 222 

 Holdover storage, 96, 274 

 Humid regions, 25, 91, 99 

 Hydroelectric power, use of water in, 



214 

 Hydrologic cycle, definition of, 15 



legal priorities of, 249 



natural priorities of, 17 



phases of, 19, 234 



unity of, 231 

 Hydrologic data, analysis of, 233 



collection of, 232, 233 



coordination of, 234-236 



national policy for, 235 



Importation of water, 68 

 Industrial use of water, 213 



