Abstract: Experiments using highly turbid water from playa lakes for injection into the Ogallala Formation have resulted in greatly decreased yield of the recharge wells. Recharge of ground or surface water of good quality has indicated, however, that injection through wells in an effective method of recharging the aquifer. Water that is slightly turbid can be successfully injected for a period of time, but generally results in constantly declining yields and capacity for recharge. Redevelopment through pumping and surging significantly prolongs the life of recharge wells under some conditions. Surface spreading is little practiced on the High Plains, but locally may be a feasible means of artificial recharge.

Abstract: Ground water continues to discharge into the Navidad and Lavaca Rivers by seepage out-flow even though large amounts of ground water are pumped for irrigation. Although a reduction in streamflow probably has occurred, a complete loss of the low flow of the streams by infiltration to a lowered water table seems remote. The large ground-water withdrawals will continue to cause land-surface subsidence, which will range from 0.012 foot to more than 0.026 foot per year. A minimum of about 0.013 to 0.015 foot of annual subsidence at the upper ends of the proposed reservoir and a maximum of about 0.019 foot near the dam site can be expected. Structural failures of manmade features have not occurred from the subsidence, but regional changes in the land slope have occurred and will continue . Numerous fault traces have been mapped in the area, but most of the faults are inactive. If movement along the fault planes should occur, the vertical displacement probably will not exceed the total subsidence.