100 CONSERVATION OF GROUND WATER 



tain seasons, it has been possible to develop other ground-water 

 or surface-water supplies and thus reduce the draft in the af- 

 fected area. Other corrective measures that are effective in 

 many areas are the development of wells in untapped portions 

 of the aquifer or redistribution of wells to draw from a more 

 extensive part of the aquifer. All these measures tend to 

 reduce the concentrated draft upon a small portion of the 

 aquifer. 



Some ground-water shortages due to concentrated pumping 

 have been overcome by artificial recharge, supplementing the 

 natural recharge by spreading grounds, canals, or ponds. When 

 the wells are remote from the recharge area, however, the 

 limiting factor is commonly the transmissivity of the aquifer 

 rather than the quantity of water available for replenishment 

 of that aquifer. Helping nature then is no satisfactory solu- 

 tion. It is necessary instead to by-pass the natural circulation 

 system and get the water into the aquifer in the area of use, 

 where the shortage of water occurs. Recharge wells have been 

 successful in such replenishment in some areas but sad failures 

 in others, and it is evident that considerable development in 

 the techniques of artificial recharge is needed. 



Pumping itself increases the rate of movement from the re- 

 charge area to the wells, by increasing the hydraulic gradient. 

 In several areas the water levels in wells have reached approxi- 

 mate equilibrium after years of pumping, indicating that the 

 pumped water is now replaced by inflow of water through the 

 aquifer. This solution is not satisfactory, however, where it 

 requires pumping lifts so great as to make the cost of water 

 prohibitive, or where the aquifer would be un watered in the 

 process of establishing a favorable hydraulic gradient. Obvi- 

 ously where pumping has created conditions favorable for in- 

 flow to the aquifer of unusable water, the situation will not 

 correct itself by further pumping. The remedial measures for 

 salt-water encroachment require either a reduction of pump- 

 ing draft or the artificial replenishment of the aquifer where 

 the storage is being depleted. 



