Summary of water resources for the Campo, Cuyapaipe, La Posta, and Manzanita Indian Reservations and vicinity, San Diego County, California

Since 1945, precipitation and runoff in California on the Campo, Cuyapaipe, La Posta, and Manzanita Indian Reservations and surrounding areas generally have been below normal, and ground-water levels are declining. Most of the water is of excellent quality. The analysis of water from one well on the Campo Reservation indicates a concentration of nitrate that exceeds the recommended limit established in 1972 by the U.S. Environmental Protection Agency. Most wells and springs in the study area yield water for domestic purposes. The yields range from less than 1 gallon per minute to 210 gallons per minute. Most of the water is produced from shallow aluvial-filled channels or from consolidated rocks that are deeply weathered locally or highly fractured. The well data show that insufficient water is available on the four reservations for large-scale irrigation. (Woodard-USGS)