Addressing Nitrate in California’s Drinking Water Technical Report 7: Alternative Water Supply Options for Nitrate Contamination

University of California, Davis (UC Davis) | July 2nd, 2012

The Tulare Lake Basin and Salinas Valley were chosen as pilot study areas because communities in these regions are faced with the need to manage high nitrate loads from

The Tulare Lake Basin and Salinas Valley were chosen as pilot study areas because communities in these regions are faced with the need to manage high nitrate loads from agricultural lands and dairies, have a high risk of exposure to nitrate contamination in groundwater, and often cannot afford treatment or alternative water supply options. These factors combine to make the Tulare Lake Basin and Salinas Valley highly susceptible to health effects from nitrate in drinking water. There are 371 active community public water systems (CPWS) and 30 state small water systems (SSWS) in the study area (281 and 120 in the Tulare Lake Basin and Salinas Valley, respectively). These systems supply water to about 2.4 million people. An estimated additional 245,490 people in these regions get their drinking water from an estimated 74,400 private domestic wells (self-supplied households or local small water systems with fewer than five connections) that are unregulated and largely unmonitored.

Addressing Nitrate in California’s Drinking Water Technical Report 8: Regulatory and Funding Options for Nitrate Groundwater Contamination

University of California, Davis (UC Davis) | July 2nd, 2012

In the long-term, many regulatory options could reduce nitrate contamination from nonpoint sources, but some are preferable to others in terms of abatement costs; monito

In the long-term, many regulatory options could reduce nitrate contamination from nonpoint sources, but some are preferable to others in terms of abatement costs; monitoring and enforcement costs; information requirements; and the ability to raise revenue. Overall, regulation of fertilizer is easier to design, administer, and enforce than regulation of diffuse nitrate leachate discharges to groundwater. Market-based regulatory approaches (of fertilizer application or of nitrate leachate) often can achieve a water quality target at a lower cost than prescriptive standards. However, no regulatory option is without its drawbacks: e.g., regulation of fertilizer may not achieve the drinking water quality objective at all drinking water systems. Despite the existence of funding programs for safe drinking water, additional funding sources are needed. A fertilizer fee is a promising funding source that also creates incentives for dischargers to use fertilizer and water more efficiently. Farmers are currently exempt from a sales tax on fertilizer (if applied to land used for food or for feed for food animals) (CA State Board of Equalization 2004), so if this fee were set at a sales tax rate of 7.5% on the cost of nitrogen, it has the potential to raise an estimated $28 million annually, 12 nearly enough to provide alternative water supplies to the highly susceptible populations in the study area.

Addressing Nitrate in California’s Drinking Water with a Focus on Tulare Lake Basin and Salinas Valley Groundwater

University of California, Davis (UC Davis) | March 1st, 2012

In 2008, Senate Bill SBX2 1 (Perata) was signed into law (Water Code Section 83002.5), requiring the State Water Resources Control Board (State Water Board), in consultat

In 2008, Senate Bill SBX2 1 (Perata) was signed into law (Water Code Section 83002.5), requiring the State Water Resources Control Board (State Water Board), in consultation with other agencies, to prepare a Report to the Legislature to “improve understanding of the causes of [nitrate] groundwater contamination, identify potential remediation solutions and funding sources to recover costs expended by the State to clean up or treat groundwater, and ensure the provision of safe drinking water to all communities.” The University of California prepared this Report under contract with the State Water Board as it prepares its Report to the Legislature.  This executive summary focuses on major findings and promising actions. Details can be found in the Main Report and eight accompanying Technical Reports. Technical Report 1: Project and Technical Report Outline (Version July 2012) Technical Report 2: Nitrogen Sources and Loading to Groundwater (Version July 2012) Appendix, Technical Report 2: Appendix Figures to Technical Report 2 (Version July 2012) - 84 MB (large file) Technical Report 3: Nitrogen Source Reduction to Protect Groundwater Quality (Version July 2012) Technical Report 4: Groundwater Nitrate Occurrence (Version July 2012) Technical Report 5: Groundwater Remediation and Management for Nitrate (Version July 2012) Technical Report 6: Drinking Water Treatment for Nitrate (Version July 2012) Technical Report 7: Alternative Water Supply Options for Nitrate Contamination (Version July 2012) Technical Report 8: Regulatory and Funding Options for Nitrate Groundwater Contamination U.C. Davis Groundwater Nitrate Project links and updates

Alamitos Barrier Project: Annual Report on the Control of Seawater Intrusion 2016-2017

Los Angeles County Department of Public Works (LACDPW) | June 30th, 2017

The Alamitos Barrier Project (ABP) was designed and constructed to protect the groundwater supplies of the Central/Orange County Basin of the Coastal Plain

The Alamitos Barrier Project (ABP) was designed and constructed to protect the groundwater supplies of the Central/Orange County Basin of the Coastal Plain from the intrusion of seawater through the Alamitos Gap area. The project facilities are located near the Los Angeles-Orange County border about two miles inland from the terminus of the San Gabriel River. The original facilities included injection wells to form a freshwater pressure ridge and extraction wells to form a saltwater trough. The freshwater pressure ridge has proven to be historically effective, whereas the saltwater trough has not. As a result, the extraction wells are currently not in operation. A map showing the supply pipeline, injection wells, extraction wells, and observation wells is shown on page A-12.1. The County of Los Angeles Department of Public Works (Public Works) operates and maintains the ABP and its associated facilities under the direction and approval of the Joint Management Committee (JMC), acting on behalf of the Los Angeles County Flood Control District (LACFCD) and the Orange County Water District (OCWD). This report summarizes design and construction issues, operation and maintenance activities, hydrogeologic effects, chloride concentrations, and project costs for Fiscal Year (FY) 2016-17 (i.e., July 1, 2016 through June 30, 2017).

Analysis of the Carmel Valley Alluvial Ground-Water Basin, Monterey County, California

U.S. Geological Survey (USGS) | June 14th, 1984

A two-dimensional, finite-element, digital model was developed for the Carmel Valley alluvial ground-water basin using measured, computed, and estimated discharge

A two-dimensional, finite-element, digital model was developed for the Carmel Valley alluvial ground-water basin using measured, computed, and estimated discharge and recharge data for the basin. Discharge data included evapotranspiration by phreatophytes and agricultural, municipal, and domestic pumpage. Recharge data included river leakage, tributary runoff, and pumping return flow. Recharge from subsurface boundary flow and rainfall infiltration was assumed to be insignificant. From 1974 through 1978, the annual pumping rate ranged from 5,900 to 9,100 acre-feet per year with 55 percent allotted to municipal use principally exported out of the valley, 44 percent to agricultural use, and 1 percent to domestic use. The pumpage return flow within the valley ranged from 900 to 1,500 acre-feet per year. The aquifer properties of transmissivity (about 5,900 feet squared per day) and of the storage coefficient (0.19) were estimated from an average alluvial thickness of 75 feet and from less well-defined data on specific capacity and grain-size distribution. During calibration the values estimated for hydraulic conductivity and storage coefficient for the lower valley were reduced because of the smaller grain size there. The river characteristics were based on field and laboratory analyses of hydraulic conductivity and on altitude survey data. The model is intended principally for simulation of flow conditions using monthly time steps. Time variations in transmissivity and short-term, high- recharge potential are included in the model. The years 1974 through 1978 (including "pre-" and "post-" drought) were selected because of the extreme fluctuation in water levels between the low levels measured during dry years and the above-normal water levels measured during the preceding and following wet years. Also, during this time more hydrologic information was available. Significantly, computed water levels were generally within a few feet of the measured levels, and computed flows were close to gaged river flows for this simulation. However, the nonuniqueness of solutions with respect to different sets of data indicates the model does not necessarily validate the correctness of the individual variables. The model might be improved with additional knowledge of the distribution of confining sediments in the lower end of the valley and the aquifer properties above and below them. The solution algorithm could account for confinement or partial confinement in the lower end of the valley plus contributions from the Tularcitos aquifer.

Annual Investigation and Report of Groundwater Conditions within United Water Conservation District

United Water Conservation District (UWCD) | March 8th, 2016

Bulletin 39-I, South Coastal Basin Investigation, Records of Ground Water Levels at Wells for the Year 1940, Precipitation Records for the Season 1939-40

California Department of Water Resources (DWR) | July 1st, 1941

Bulletin No. 13, South Coastal Basin Investigation, Value and Cost of Water for Irrigation in Coastal Plain of Southern California

California Department of Water Resources (DWR) | June 1st, 1933

Bulletin No. 39-57, Water Supply Conditions in Southern California during 1956-1957, Volume II, Precipitation and Water Level Data Central Coastal and Los Angeles Regions

California Department of Water Resources (DWR) | June 16th, 1958

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume III Bulletin No. 39-57 Volume IV

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume III Bulletin No. 39-57 Volume IV

Bulletin No. 39-57, Water Supply Conditions in Southern California during 1956-1957, Volume III, Precipitation and Water Level Data Lahontan, Colorado River Basin, Santa Ana, and San Diego Regions

California Department of Water Resources (DWR) | June 16th, 1958

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume II Bulletin No. 39-57 Volume IV

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume II Bulletin No. 39-57 Volume IV