282 CONSERVATION OF GROUND WATER 



Plains in Texas water is currently being withdrawn at more 

 than 20 times the estimated rate of replenishment. This can 

 be done temporarily only because the irrigated parts of that 

 region are actually drawing on stored water accumulated over 

 many years in the past. The day of reckoning, however, is 

 bound to arrive. The Central Valley Program in southern 

 California is another example of overdevelopment of ground 

 water accumulated over the century. The provision of sup- 

 plemental water from surface sources in this undertaking is 

 an excellent example of what can be done where the water of 

 a major drainage basin is regarded as a unit and an over-all 

 plan is devised for its effective management. 



Managing the surface and ground waters of a drainage basin 

 as a unit is one of three principal lines of action for better con- 

 servation of ground water which emerge from Dr. Thomas's 

 survey. What is required within each basin is the planned 

 management of all available water in order that a water 

 budget, balanced on the basis of long-term averages rather 

 than annual replenishment, may be maintained. The second is 

 artificial recharge of developed reservoirs to the extent local 

 conditions and the devices of man permit. The third is man- 

 agement of recharge areas of ground-water reservoirs to pro- 

 vide maximum infiltration of precipitation, or of stream water 

 where the reservoir is along a watercourse. 



Some Representative Ground-water Problems 



The analysis below of six ground-water problems should 

 make clear what is involved in selected areas of the country 

 in translating these lines of action in day-by-day execution, 

 and indicate the kind of integrated controlled management 

 which should produce the most fruitful results. These exam- 

 ples were chosen to typify the major kinds of ground-water 

 problems encountered as well as to give a reasonably wide 

 geographic spread. In general, these problems result from ig- 

 norance of geologic and hydrologic conditions, or from lack 

 of the physical means of securing effective coordination of 



