History of Engineering Geology in the California Department of Water Resources

Abstract

Engineering geology has played an essential role in the projects of the California State Department of Water Resources (DWR). Numerous pioneering techniques by DWR geologists include a) the first active element analog/digital model of a groundwater basin, b) cost estimates for tunneling, c) test plots evaluating shallow land subsidence (hydro-compaction), d) a mobile rock mechanics laboratory, e) field and laboratory evaluations of specific yield, and f) determination of coastal aquifers subject to sea-water intrusion. Eventual results of these techniques include a) digital ground-water basin models with increasing complexity, b) and c) choice of the lowest cost route and geotechnical methods to bring water to southern California, d) rock properties available to engineers for preliminary design, e) values of storage capacity for 250 ground-water basins, and f) construction of fresh-water injection barriers to preserve ground-water basins. Geologists obtained and interpreted for their engineer colleagues the essential geologic information utilizing advanced geophysical and drilling techniques for both the California Water Plan and the State Water Project. The former is a master plan for utilization of all the water resources of the state. The latter, now essentially complete, included planning, design, and construction of 14 dams, 21 pumping plants, an underground power plant, 11 power recovery stations, 6 tunnels, and 561 mi of aqueduct, bringing water to the San Francisco Bay area and from the central and northern parts of the State to the heavily populated south. A geothermal test well completed by DWR in the Imperial Valley encountered fluid of insufficiently high temperature for economic development. DWR geologists have been active in the initial organization and the development of the Association of Engineering Geologists, and have also been active in the Geological Society of America, particularly in the Engineering Geology and Hydrogeology Divisions.