PROBLEMS FROM DEVELOPMENT 55 



order of 210,000 acre-feet a year, but there is no overdraft; 

 indeed, there is more than 100,000 acre-feet of water in stor- 

 age within 60 feet of the surface, on which draft has never 

 been made. This is the part of the ground-water reservoir 

 most readily recharged by the Salinas River and its tribu- 

 taries. On the other hand, along the lower east side of the 

 valley, the pumpage of 35,000 acre-feet is about 7,000 acre- 

 feet greater than replenishment, and the water table has 

 been receding at an average rate of % foot a year. Finally, 

 in the "pressure area" comprising the lowest part of the 

 valley, water is confined in aquifers under artesian pressure. 

 The pumping draft of 120,000 acre-feet in the pressure area 

 must be replenished by lateral movement from adjacent 

 areas, and in recent years it is estimated that during the 

 pumping season about 6,000 acre-feet of saline water has in- 

 truded into the "180-foot" aquifer from Monterey Bay. 



If 5 per cent of the present surface outflow to the ocean 

 could be salvaged and put to beneficial use, present over- 

 drafts in the east side and pressure areas could be elimi- 

 nated; and if 15 per cent of that outflow were salvaged, water 

 would be available for the 50,000 acres of irrigable land not 

 irrigated now. It has been proposed to pump water from the 

 river gravels above the pressure area, divert it through ca- 

 nals, and recharge the east-side area, where there are un- 

 saturated gravels capable of storing about 200,000 acre-feet 

 of water. The gravels above the pressure area would be re- 

 plenished from winter stream flow in normal years, and this 

 salvage would be of material advantage in providing ground- 

 water storage to tide over dry years. Salt-water encroach- 

 ment in the lower pressure area can also be reduced by in- 

 creasing the irrigation efficiency there, so as to eliminate all 

 pumping in excess of beneficial requirement. 



Several heavily developed ground-water reservoirs in 

 southern California are in valleys from which streams dis- 

 charge large quantities into the ocean during the winter. 

 The Santa Maria, Cuyama, and Santa Ynez Valleys and the 

 Oxnard Plain are like Salinas Valley in this respect. 



