Keywords:coastal aquifers, Colorado River, conjunctive use, drought, Groundwater Exchange, groundwater recharge, monitoring, water supply
AB 2222 (Caballero, Chapter 670, Statutes of 2008) requires the State Water Resources Control Board to submit a report to the Legislature that...
AB 2222 (Caballero, Chapter 670, Statutes of 2008) requires the State Water Resources Control Board to submit a report to the Legislature that identifies: 1) communities in California that rely on contaminated groundwater as a primary source of drinking water; 2) the principal contaminants and other constituents of concern; and 3) potential solutions and funding sources to clean up or treat groundwater or provide alternative water supplies.
A “community,” for the purposes of this report, is defined as a Community Public Water System (Health and Safety Code Section 116395). When this report refers to communities that rely on a contaminated groundwater source, it is referring to community public water systems that draw water from a contaminated groundwater source prior to any treatment. Over 95 percent of the 38 million Californians get their drinking water from a public water system. The findings in this report do not reflect private domestic wells or other unregulated water systems since the state does not require these groundwater users to sample their wells, and consequently a comprehensive database for these groundwater sources does not exist.
This report identifies 680 community water systems that, prior to any treatment, relied on a contaminated groundwater source during the most recent California Department of Public Health (CDPH) compliance cycle (2002-2010). It is important to note that, according to CDPH, over 98% of Californians on public water supply are served safe drinking water.
Although many water suppliers draw from contaminated groundwater sources, most suppliers are able to treat the water or blend it with cleaner supplies before serving it to the public. Consequently, when this report refers to communities that rely on contaminated groundwater, it is referring to community public water systems that draw water from one or more contaminated groundwater wells prior to any treatment or blending.
Some community water systems, however, cannot afford treatment or lack alternative water sources, and have served water that exceeds a public drinking water standard. Of the 680 community water systems that rely on a contaminated groundwater source, 265 have served water that exceeded a public drinking water standard during the most recent CDPH compliance cycle (2002-2010).
The primary goal of the Central Coast Hydrologic Region (Central Coast region) groundwater update is to expand information about region-specific groundwater conditions for...
The primary goal of the Central Coast Hydrologic Region (Central Coast region) groundwater update is to expand information about region-specific groundwater conditions for California Water Plan Update 2013, and to guide more informed groundwater management actions and policies.
A second goal is to steadily improve the quality of groundwater information in future California Water Plan (CWP) updates to a level that will enable regional water management groups (RWMGs) to accurately evaluate their groundwater resources and implement management strategies that can meet local and regional water resource objectives within the context of broader statewide objectives.
The final goal is to identify data gaps and groundwater management challenges meant to serve as a guidepost for prioritizing future data collection and funding opportunities relevant to the region.
This regional groundwater update is not intended to provide a comprehensive and detailed examination of local groundwater conditions, or be a substitute for local studies and analysis. Consequently, where information is readily available, the update does report some aspects of the regional groundwater conditions in greater detail.
Senate Bill X7 6 (SBX7 6) (Chapter 1, Statutes 2009) added provisions for Groundwater Monitoring to Division 6 of the Water Code (Water...
Senate Bill X7 6 (SBX7 6) (Chapter 1, Statutes 2009) added provisions for Groundwater Monitoring to Division 6 of the Water Code (Water Code § 10920 et seq.), and authorizes the Department of Water Resources (DWR) to establish permanent, locally managed, groundwater-elevation monitoring and reporting in all of California's 515 alluvial groundwater basins.
To implement SBX7 6, DWR developed the California Statewide Groundwater Elevation Monitoring (CASGEM) program. SBX7 6 requires DWR to report to the Governor and the Legislature by January 1, 2012, and thereafter in years ending in "5" or "0" regarding the findings of this program.
The purpose of CASGEM is to establish a program of regular and systematic monitoring of groundwater elevations and to track seasonal and long-term trends in groundwater elevations statewide. The law directs DWR to rely and build upon the many established, local, long-term groundwater monitoring and management programs conducted by local entities throughout the state. DWR's role is to coordinate the CASGEM program, to work cooperatively with local entities, and to maintain the submitted groundwater elevation data in a manner that is readily and widely available to the public. Collection and evaluation of groundwater elevation data throughout the state is an important fundamental step toward improving management of California's groundwater resources.
Within the first two years of program development, DWR has met the requirements specified in SBX7 6 to establish a statewide groundwater elevation monitoring and reporting program by January 1, 2012.
Portions of aquifers in many groundwater basins in California have degraded water quality that does not support beneficial use of groundwater. In some...
Portions of aquifers in many groundwater basins in California have degraded water quality that does not support beneficial use of groundwater. In some areas, groundwater quality is degraded by constituents that occur naturally (e.g., arsenic). In many urban and rural areas, groundwater quality degradation has resulted from a wide range of human (anthropogenic) activities.
Groundwater remediation is necessary to improve the quality of degraded groundwater for beneficial use. Drinking water supply is the beneficial use that typically requires remediation when groundwater quality is degraded.
Contaminants in groundwater can come from a many sources, naturally occurring and anthropogenic. Examples of naturally occurring contaminants include heavy metals and radioactive constituents, as well as high concentrations of various salts from specific geologic formations or conditions.
Climate change that results in altered precipitation, snowfall patterns, and rising sea levels may exacerbate salt water intrusion and flooding of low-lying infrastructure and urban facilities. These phenomena will add new challenges to protection of groundwater from contamination.
In addition, groundwater can be contaminated by anthropogenic sources with organic, inorganic, and radioactive constituents from point and non-point sources. These anthropogenic sources include industrial sites, mining operations, leaking fuel tanks and pipelines, manufactured gas plants, landfills, impoundments, dairies, septic systems, and urban and agricultural activities.
The contaminant having the most widespread and adverse impact on drinking water wells is arsenic, followed by nitrates, naturally occurring radioactivity, industrial/commercial solvents, and pesticides.
Groundwater remediation removes constituents, hereafter called contaminants, which affect beneficial use of groundwater. Groundwater remediation systems can employ passive or active methods to remove contaminants. Passive groundwater remediation allows contaminants to degrade biologically or chemically or disperse in situ over time. Active groundwater remediation involves either treating contaminated groundwater while it is still in the aquifer (in situ) or extracting contaminated groundwater from the aquifer and treating it outside of the aquifer (ex situ). Active in situ methods generally involve injecting chemicals into the contaminant plume to obtain a chemical or biological removal of the contaminant. Ex situ methods for treating contaminated groundwater can involve physical, chemical, and/or biological processes.