2016 Annual Report of Hydrogeologic Conditions, Water Requirements, Supplies and Disposition Santa Maria Valley Management Area

City of Santa Maria | April 13th, 2017

This annual report of conditions in the Santa Maria Valley Management Area, for calendar year 2016, has been prepared to meet the reporting conditions of the June 30, 20

This annual report of conditions in the Santa Maria Valley Management Area, for calendar year 2016, has been prepared to meet the reporting conditions of the June 30, 2005, Stipulation entered by the Superior Court of the State of California, County of Santa Clara, in the Santa Maria Valley Groundwater Basin litigation. The Stipulation divided the overall Santa Maria Valley Groundwater Basin into three management areas, the largest of which overlies the main Santa Maria Valley (the Santa Maria Valley Management Area, or SMVMA) and is the subject of this report. The other two management areas, the Nipomo Mesa Management Area (NMMA) and the Northern Cities Management Area, are addressed in separate annual reports prepared by others. The Stipulation, approved and implemented in 2008, specifies that monitoring shall be sufficient to determine groundwater conditions, land and water uses, sources of water supply, and the disposition of all water supplies in the Basin. Annual Reports for the SMVMA are to summarize the results of the monitoring and include an analysis of the relationship between projected water demand and supply. The Stipulation was preserved in the California Court of Appeal (Sixth Appellate District) Decision of November 21, 2012, and in the Superior Court of the State of California (County of Santa Clara) Final Judgment of April 23, 2014. Thus, the Physical Solution criteria for monitoring and managing groundwater in the basin remain. In accordance with the Stipulation, this report on the SMVMA provides a description of the physical setting and briefly describes previous studies conducted in the groundwater basin, including the long-term monitoring program developed for the SMVMA. As reported herein, the Twitchell Management Authority (TMA) commissioned the preparation of a monitoring program for the SMVMA in 2008, and its complete implementation is expected to provide the data with which to fully assess future conditions. This report describes hydrogeologic conditions in the management area historically and through 2016, including groundwater conditions, Twitchell Reservoir operations, and hydrologic and climatic conditions. As with all previous annual reports (commencing in 2008), the water requirements and supplies for agricultural and municipal uses are accounted, as are the components of water disposition in the SMVMA. Conclusions drawn regarding water resource conditions are discussed, including any finding of severe water shortage, which is concluded to not be the case through 2016. Finally, recommendations are provided with regard to the intra-basin transfer of water from the SMVMA to the NMMA, possible enhancement of groundwater recharge, expanded assessment of water resource conditions, and continued implementation of the monitoring program for the SMVMA. Janny Choi from Stanford University's Water in the West discusses the Santa Maria stipulation in the 2014 paper Before the Well Runs Dry: Improving the Linkage Between Groundwater and Land Use Planning.

A Basin-Scale Approach to Estimating Recharge in the Desert: Anza-Cahuilla Groundwater Basin, CA

American Water Resources Association (AWRA) | November 2nd, 2021

The Anza-Cahuilla groundwater basin located mainly in the semi-arid headwaters of the Santa Margarita River watershed in southern California is the principle source of g

The Anza-Cahuilla groundwater basin located mainly in the semi-arid headwaters of the Santa Margarita River watershed in southern California is the principle source of groundwater for a rural disadvantaged community and two Native American Tribes, the Ramona Band of Cahuilla and the Cahuilla. Groundwater in the study area is derived entirely from precipitation and managing groundwater sustainably requires an accurate assessment of the water balance components, yet long-term estimates do not exist. Demand for groundwater in the region has increased and groundwater quality has decreased due to population growth and increased irrigated cropland. To characterize monthly long-term natural recharge and runoff estimates, a physically-based water balance model (Basin Characterization Model) was locally calibrated and validated using nearby streamgages and published estimates of climatic and hydrologic variables. The average modeled annual recharge and runoff from 1981 to 2010 was 5.4 × 106 and 1.2 × 107 m3, respectively, for the study area. Recharge and runoff do not reliably occur in large amounts every year and recharge rarely occurs in the groundwater basin footprint. These long-term estimates can be used by water managers, stakeholders, and Native American Tribes to develop plans for sustainable management of future water resources, and as inputs to a three-dimensional groundwater model.

A geohydrologic reconnaissance of the Saratoga Spring area, Death Valley National Monument, California

U.S. Geological Survey (USGS) | March 1st, 1966

A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California

U.S. Geological Survey (USGS) | July 1st, 2002

Ambient noise differential adjoint tomography reveals fluid-bearing rocks near active faults in Los Angeles

Nature Portfolio (Springer Nature) | October 28th, 2023

An Estimated Potentiometric Surface of the Death Valley Region, Nevada and California, Developed Using Geographic Information System and Automated Interpolation Techniques

U.S. Geological Survey (USGS) | July 1st, 1998

Appraisal of the water resources of Death Valley, California–Nevada

U.S. Geological Survey (USGS) | December 1st, 1977

Bulletin 118: California's Groundwater Update 2020 (draft)

California Department of Water Resources (DWR) | March 1st, 2021

Groundwater is a precious and limited resource that is used in meeting the needs of California’s large and small urban areas, rural groundwater users, irrigated agricul

Groundwater is a precious and limited resource that is used in meeting the needs of California’s large and small urban areas, rural groundwater users, irrigated agriculture, and the environment. Since the last California’s Groundwater (CalGW) Update in 2003, there has been significant changes to land use, water use, water application practices, and water allocations. In addition, the effects of climate change have affected California’s reliance on groundwater. It is expected that there will be additional changes in land use, water use, adjustments in water allocations, and that climate change will continue to affect the environment, thus elevating the importance of the reporting in CalGW Updates.  According to the last comprehensive report, California’s Groundwater Update 2003 (CalGW Update 2003), California’s reliance on groundwater was approximately 30 percent during a wet-to-average precipitation water year and approximately 40 percent during dry periods. Since then, the percentage of groundwater reliance has increased to between 30 and 40 percent during above normal to-wet years and to as much as 58 percent during dry periods (California Department of Water Resources 2018).

Bulletin No. 3 Water Resources of Tulare County and Their Utilization

State of California | August 29th, 1922

Bulletin No. 84 Mojave River Ground Water Basins Investigation

California Department of Water Resources (DWR) | August 15th, 1967

Click here for Bulletin No. 84 maps and plates.

Click here for Bulletin No. 84 maps and plates.