Groundwater geochemistry in southeastern San Joaquin Valley, California

South of the Kern River and east of the line Bakersfield-San Emigdio Creek, ground-waters pumped for irrigation occur in several chemical and geographic types. These are: (1) Kern, (2) Caliente, (3) El Paso, (4) San Emigdian, (5) Grapevine Transition, (6) East Bakersfield, (7) Kern Mesa, (8) Saline. The first four comprise the main water-body and underlie most of the area; they are chemically related to the recharging streams. Type 5 may represent a wide interface between 3 and 4. The remaining types are not related to their local streams. Types 6 and 7 are complexes that can not yet be subdivided; structural controls are important to their occurrence. Type 8 represents natural contamination of the groundwater reservoir by petroleum brines. Abnormal quantities of boron northeast of Arvin are superimposed on the Caliente type by additions of juvenile waters. Pollution by the petroleum industry is not now significant. Generally, vertical zoning of the chemical types is not pronounced. Although most of the groundwaters are eminently suitable for irrigation, some are not of desirable quality for that purpose.