This is a study of the feasibility of recharging, in the Waterman Canyon-East Twin Creek area, imported water from northern California by way of the State Water Project beginning in 1972.
The feasibility of recharging 30,000 acre-feet of water a year in the Waterman Canyon-East Twin Creek area will depend on the effectiveness of fault K as a barrier to ground-water movement near the land surface. The results of test drilling and an infiltration test indicate that the subsurface material at the spreading grounds is permeable enough to allow recharged water to percolate to the water table. The data indicate that fault K extends into the Waterman Canyon-East Twin Creek area and may impede the lateral movement of recharged water. Fault K has no known surface expression and therefore probably does not affect the highly permeable younger alluvium. If that is so, fault K will be less effective as a barrier to ground-water movement as the recharge mound rises. Monitoring of the observation wells near the spreading grounds as the planned recharge operation proceeds should provide data about the hydrologic effects of fault K near the land surface.