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Chapter 7: Groundwater Resources and Groundwater Quality Chapter 7 1 Groundwater Resources and 2 Groundwater Quality 3 7.1 Introduction 4 This chapter describes groundwater resources and groundwater quality in the 5 Study Area, and potential changes that could occur as a result of implementing the 6 alternatives evaluated in this Environmental Impact Statement (EIS). 7 Implementation of the alternatives could affect groundwater resources through 8 potential changes in operation of the Central Valley Project (CVP) and State 9 Water Project (SWP) and ecosystem restoration. 10 7.2 Regulatory Environment and Compliance 11 Requirements 12 Potential actions that could be implemented under the alternatives evaluated in 13 this EIS could affect groundwater resources in the areas along the rivers impacted 14 by changes in the operations of CVP or SWP reservoirs and in the vicinity of and 15 lands served by CVP and SWP water supplies. Groundwater basins that may be 16 affected by implementation of the alternatives are in the Trinity River Region, 17 Central Valley Region, San Francisco Bay Area Region, Central Coast Region, 18 and Southern California Region. 19 Actions located on public agency lands or implemented, funded, or approved by 20 Federal and state agencies would need to be compliant with appropriate Federal 21 and state agency policies and regulations, as summarized in Chapter 4, Approach 22 to Environmental Analyses. 23 Several of the state policies and regulations described in Chapter 4 have resulted 24 in specific institutional and operational conditions in California groundwater 25 basins, including the basin adjudication process, California Statewide 26 Groundwater Elevation Monitoring Program (CASGEM), California Sustainable 27 Groundwater Management Act (SGMA), and local groundwater management 28 ordinances, as summarized below. 29 7.2.1 Groundwater Basin Adjudication 30 Basin adjudications are determined through court decisions or pre-court mediation 31 on litigation that determine the groundwater rights of all the groundwater users 32 overlying the basins. The court identifies the extractors or well owners and the 33 amount of groundwater those well owners are allowed to extract, and appoints a 34 Watermaster whose role is to ensure that the basin is managed in accordance with 35 the court's decree. The Watermaster must report periodically to the court. There 36 are currently 23 adjudicated groundwater basins in California, most of which are Draft LTO EIS 7-1 Chapter 7: Groundwater Resources and Groundwater Quality 1 located in Southern California. Table 7.1 lists the adjudicated groundwater basins 2 located in the Study Area. 3 Table 7.1 Adjudicated Groundwater Basins in the Study Area Date of Final Court Basin Name Decision County Antelope Valley Groundwater Basin Under way Kern and Los Angeles Beaumont – Upper Santa Ana Groundwater 2004 Riverside Basin Brite Groundwater Basin 1970 Kern Central Subbasin of the Coastal Plain of 1965 Los Angeles Los Angeles Basin Chino Subbasin of the Upper Santa Ana Valley 1978 Riverside and San Basin Bernardino Cucamonga Subbasin of the Upper Santa Ana 1978 San Bernardino Valley Basin Cummings Valley Groundwater Basin 1972 Kern Goleta Groundwater Basin 1989 Santa Barbara San Jacinto Groundwater Basin 2013 Riverside Los Osos Valley Groundwater Basin Under way San Luis Obispo Mojave Basin Area (Lower Mojave River Valley, 1996 San Bernardino Middle Mojave River Valley, Upper Mojave River Valley, El Mirage Valley, and Lucerne Valley groundwater basins) San Gabriel Valley Groundwater Basin – 1973 Los Angeles excluding Raymond Groundwater Basin San Gabriel Valley Groundwater Basin – Puente 1985 Los Angeles Narrows Raymond Groundwater Basin 1944 Los Angeles Rialto-Colton Subbasin of the Upper Santa Ana 1961 San Bernardino Valley Basin Santa Margarita River Watershed – Santa 1966* Riverside and San Margarita Valley, Temecula Valley, and Cahuilla Diego Valley groundwater basins Santa Maria Valley Groundwater Basin 2008 San Luis Obispo and Santa Barbara Santa Paula Subbasin of the Santa Clara River 1996 Ventura Valley Groundwater Basin Six Basins Area in upper Santa Ana Valley 1998 Los Angeles and San Bernardino Tehachapi Valley West Basin and Tehachapi 1973 Kern Valley East Basin 7-2 Draft LTO EIS Chapter 7: Groundwater Resources and Groundwater Quality Date of Final Court Basin Name Decision County Upper Los Angeles River Area– 1979 Los Angeles San Fernando Valley Groundwater Basin Warren Valley Groundwater Basin 1977 San Bernardino West Coast Subbasin of the Coastal Plain of Los 1961 Los Angeles Angeles Basin Western San Bernardino – Upper Santa Ana 1969 San Bernardino Groundwater Basin 1 Sources: DWR 2003a, 2014a; LOCSD 2013 2 Note: 3 * Santa Margarita Watershed Adjudication addresses both groundwater and surface 4 water if water contributes to Santa Margarita River and its tributaries flows (SMRW 2014). 5 The agreements include interlocutory judgements for Murrieta-Temecula Groundwater 6 Basin that describes non-Indian water rights subject to court jurisdiction, land and water 7 rights not subject to court jurisdiction, reserved water rights for the Pechanga 8 Reservation, appropriative storage and diversion rights in conjunction with use of 9 groundwater by the Vail Company. 10 7.2.2 California Statewide Groundwater Elevation 11 Monitoring Program 12 Senate Bill X7-6, enacted in November 2009, mandates a statewide groundwater 13 elevation monitoring program to track seasonal and long-term trends in 14 groundwater elevations in California’s groundwater basins defined in 15 Bulletin 118. This amendment to Division 6 of the Water Code, specifically 16 Part 2.11 Groundwater Monitoring, requires the collaboration between local 17 monitoring entities and California Department of Water Resources (DWR) to 18 collect groundwater elevation data. The law requires local agencies to monitor 19 and report the groundwater elevation in the basins. To achieve this goal, DWR 20 developed the CASGEM Program to establish a permanent, locally-managed 21 program of regular and systematic monitoring in all of the state’s alluvial 22 groundwater basins. 23 DWR is required to establish a priority schedule for monitoring groundwater 24 basins, and to report to the Legislature on the findings from these investigations 25 (Water Code section 10920 et. seq). The 2012 CASGEM Status Report to the 26 Legislature describes that more than 400 monitoring entities have been identified 27 and water level data are being submitted to DWR (DWR 2012). The 28 prioritization of basins is to identify, evaluate, and determine the need for 29 additional groundwater level monitoring. The prioritization approach includes the 30 following eight criteria. 31 • Overlying population in the groundwater basin 32 • Projected growth of the overlying population 33 • Number of public water supply wells Draft LTO EIS 7-3 Chapter 7: Groundwater Resources and Groundwater Quality 1 • Total number of water supply wells 2 • Irrigated acreage overlying the groundwater basin 3 • Reliance on groundwater as the primary source of water by the overlying 4 land uses 5 • Impacts on groundwater, including overdraft, subsidence, saline intrusion, and 6 other water quality degradation 7 • Any other information relevant to the groundwater conditions 8 Groundwater basins designations in the study area are described for each basin in 9 the following subsection of this chapter (DWR 2014e). 10 7.2.3 Sustainable Groundwater Management Act 11 In September 2014, the SGMA was enacted. The SGMA establishes a new 12 structure for locally managing California’s groundwater in addition to existing 13 groundwater management provisions established by Assembly Bill (AB) 14 3030 (1992), Senate Bill (SB) 1938 (2002), and AB 359 (2011), as well as 15 SBX7-6 (2009). 16 The SGMA includes the following key elements: 17 • Provides for the establishment of a Groundwater Sustainability Agency (GSA) 18 by one or more local agencies overlying a designated groundwater basin or 19 subbasin identified in DWR Bulletin 118-03 20 • Requires all DWR Bulletin 118 groundwater basins found to be of “high” or 21 “medium” priorities to prepare Groundwater Sustainability Plans (GSPs) 22 • Provides for the proposed revisions, by local agencies, to the boundaries of a 23 DWR Bulletin 118 basin, including the establishment of new subbasins 24 • Provides authority for DWR to adopt regulations to evaluate GSPs, and 25 review the GSPs for compliance every 5 years 26 • Requires DWR to establish best management practices and technical measures 27 for GSAs to develop and implement GSPs 28 • Provides regulatory authority to the State Water Resources Control Board 29 (SWRCB) for developing and implementing interim groundwater 30 management plans under certain circumstances (such as lack of compliance 31 with development of GSPs by GSAs) 32 The SGMA defines sustainable groundwater management as “the management 33 and use of groundwater in a manner that can be maintained during the planning 34 and implementation horizon without causing undesirable results.” Undesirable 35 results are defined as any of the following effects. 36 • Chronic lowering of groundwater levels (not including overdraft during a 37 drought if a basin is otherwise managed) 38 • Significant and unreasonable reduction of groundwater storage 7-4 Draft LTO EIS Chapter 7: Groundwater Resources and Groundwater Quality 1 • Significant and unreasonable seawater intrusion 2 • Significant and unreasonable degraded water quality, including the
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