Ground-water storage in the Johnson Valley area, San Bernardino County, California

The Mojave Water Agency includes several desert basins where ground water in storage is many times as great as the average annual recharge. The Johnson Valley area in San Bernardino County, Calif., was evaluated for (1) the quantity of ground water in storage, (2) the chemical quality of the ground water, and (3) the potential for storage of recharge water in the unsaturated zone. Johnson Valley contains about 250,000 acre-feet of water in storage, of which about half can be considered recoverable. About 250,000 acre-feet of void space in the unsaturated alluvium is available for storage of imported water, but not all of the recharged water could be recovered. The quality of the water in storage is satisfactory for public consumption, although water from some areas has high floride concentrations and should be mixed with water of low fluoride concentration.