Selenium toxicity in the western San Joaquin Valley, groundwater export from the Owens Valley coupled with vegetation survivability studies, and the pending water-quality standards/water-rights hearing for the San Francisco Bay/Delta are just a few of the controversial and important efforts with which we are involved. All these studies are providing valuable data and methods development that contribute significantly to the science of hydrology.

After almost a century of activity and publication of approximately 2,100 water-resources related reports for the State of California, one needs to ask: Have we as an agency improved the level of understanding of the hydrologic environment in the State? Have we provided sufficient data and interpretive products that are necessary for sound decisionmaking to the water-management community? A century of existence certainly demonstrates an historical role for the U.S. Geological Survey in the hydrologic community. The resulting 2,100 reports continue to serve as the foundation of hydrologic knowledge for the State of California. Additionally, hydrologic historians will note: (1) The evolution and sophistication of the investigative and interpretive tools used to collect and transfer hydrologic data and knowledge to the water user community, and (2) a strong and steadfast adherence to the essence of science and the maintenance of our unbiased and nonregulatory stance in the midst of highly controversial and political issues. The justification for this stance is simple the need has existed and will continue to exist for an unbiased entity such as the U.S. Geological Survey to produce scientific, credible information. The major national water issues for the Water Resources Division in 1988 correspond well to water issues in the State of California. These issues are (1) Water availability and competition for this water; (2) quality of water; and (3) management of water and land resources. Studies being conducted by the U.S. Geological Survey and described in this publication are, for the most part, in support of providing data and interpretation to address these issues. As an agency, we are aware of and dedicated to the premise that credible data are obtained only when subjected to consistent, discipline related, quality-assurance programs. Throughout the Water Resources Division, continuous quality-assurance programs are conducted of all the activities that influence and ensure the quality of our products and services. These documented and proven quality-assurance programs provide to the hydrologic community necessary confidence that our products and services will meet the most stringent criteria. Several of the most relevant and visible studies being conducted by the California District deal with selenium toxicity in the western San Joaquin Valley; groundwater export from the Owens Valley, coupled with vegetation survivability studies; hydrodynamics variability in San Francisco Bay; reclaimed water use; seawater intrusion in the Santa Barbara area; and involvement in the water-quality standard/water-rights hearing for the San Francisco Bay/Delta. These studies and the others described herein are providing valuable data and methods development that continue to contribute significantly to the science of hydrology and the water-management community within the State.