1G – Groundwater Protection

Management Measure

To manage groundwater quality:

1. Reduce or eliminate the leaching of irrigation water into or around drinking water wells.
2. If your field is located within a groundwater protection area, make sure to avoid the use of contaminant pesticides.

To manage groundwater quantity:

1. Use fallow agricultural fields to artificially recharge groundwater in areas where the groundwater basin is depleting.

Management Practices

• Manage irrigation water volume and timing to reduce or eliminate runoff and/or leaching to ground water. Use crop and region specific evapotranspiration rates and/or soil moisture probes to determine when the best time and for how long to irrigate.
• Eliminate the use of 6800a list, contaminant pesticides in identified ground water protection areas (GWPA). If the use of any of the contaminant pesticides is necessary, obtain a permit from your counties Agriculture Commissioner.
• Use fallow agricultural fields to artificially recharge ground water in areas where the ground water basin is depleting. Shallow surface water that is allowed to infiltrate through the soil matrix, over a period of several months per year, increases the bioattenuation rates of pollutants. Unless agricultural irrigation return flows are of good quality, artificially recharging ground water by direct injection into groundwater wells is not recommended due to the lack of soil-microbial interactions (bioattenuation) and the high probability of groundwater well contamination.

Programs

• Farmington Groundwater Recharge Program goal is to recharge an average of 35,000 acre-feet of water annually into the Eastern San Joaquin Basin, a groundwater basin generally bound by Highway 99, Jake Tone Road, Mokelumne River and Temple Creek. It is a region that for a half-century has seen groundwater levels decline an average of 1.7 feet per year, with some areas dropping to 100 feet below historic levels. Coupled with this overdraft, it is estimated that the basin has lost up to 2 million acre feet of storage capacity*. As a result, water quality has declined as saline tainted water from the west has been moving eastward into the basin at a rate of up to 150 feet per year.
• Department of Water Resources (DWR) manages groundwater resources by mapping the state’s groundwater basins, keeping well reports (drillers well logs), assigning well numbers, and conducting focused investigations to capture relevant data.
• Department of Pesticide Regulations (DPR) Ground Water Protection Program determines where and how pesticides are contaminating ground water, identifies areas sensitive to pesticide contamination and develops mitigation measures to prevent that movement. We also adopt regulations and do outreach to carry out those mitigation measures. The measures are designed to prevent continued movement to ground water in contaminated areas and to prevent problems before they occur in other areas. Some of the 6800[a] list of ground water contaminant pesticides, include the following (common brand names in parenthesis): Atrazine (Aatrex), Simazine (Princep), Bromacil ( Hyvar, Krovar), Diuron (Karmex, Krovar), Prometon (Pramitol), Bentazon (Basagran), and Norflurazon (Solicam, Predict, Zorial).
• Department of Public Health, Drinking Water Program (DWP) regulates public water systems; oversees water recycling projects; permits water treatment devices; certifies drinking water treatment and distribution operators; supports and promotes water system security; provides support for small water systems and for improving technical, managerial, and financial (TMF) capacity; provides funding opportunities for water system improvements. DWP is within the Division of Drinking Water and Environmental Management.
• SWRCB, Groundwater Ambient Monitoring Assessment (GAMA) Program goal is to improve statewide ambient groundwater quality monitoring and assessment and to increase the availability of information about groundwater quality to the public. Stewardship of the state's groundwater resources is the shared responsibility of all levels of the government and community. Participation in the GAMA Program is voluntary.
• USEPA, Office of Ground Water & Drinking Water together with states, tribes, and its many partners, protects public health by ensuring safe drinking water and protecting ground water. OGWDW, along with EPA's ten regional drinking water programs, oversees implementation of the Safe Drinking Water Act, which is the national law safeguarding tap water in America.

Information Resources

• Department of Water Resources (DWR) Groundwater Information Center contains information and links for teachers and non-technical audiences, provides technical and financial assistance programs for groundwater managers, contains information and links to relevant laws and legislation, DWR publications, other references, FAQ sheets, and DWR contacts.
• DWRs California Irrigation Management Information System (CIMIS) provides crop coefficients (Kc) along with ETo to estimate specific crop evapotranspiration rates. A basic irrigation scheduling application is available as a Microsoft excel spreadsheet.
• UC Davis, Land and Water Resources (LAWR) has a program dedicated to the study of irrigation problems and techniques. We develop and extend research based information that promotes environmentally sound agricultural practices and that improve the efficient utilization of California's valuable water resource.
• UC Davis LAWR, drought trip 92-52, Irrigating Up Crops Efficiently with Sprinklers provides guidance to help determine how long sprinklers should run can be easily if the crop evapotranspiration rate and reference evapotranspiration rates are known.
• US Geologic Survey, Artificial recharge is the practice of increasing by artificial means the amount of water that enters a ground-water reservoir (Todd, 1959). This includes, for example, direction of water to the land surface through canals, irrigation furrows or sprinkler systems, and injection of water into the subsurface through wells.

(Updated 1/23/09)