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Eastern San Joaquin Groundwater Basin Groundwater Management Plan Northeastern San Joaquin County Section 4 Groundwater Banking Authority 82 Groundwater Management Options and priority. However, protected areas or Areas of Origin within the Sacramento/San Joaquin Delta watershed receive priority when considering water right appropriations. Water code §1216 states that, “A protected area shall not be deprived directly or indirectly of the prior right to all the water reasonably required to adequately supply the beneficial needs of the protected area… by a water supplier exporting or intending to export water for use outside a protected area…” Historically, the interpretation of the statute has favored those who export water from the Delta, nevertheless pending legal action and political pressure could increase water allocations to Eastern San Joaquin County and give priority to future water right applications. 4.1.1.2 Maximizing Existing Surface Water Supplies Agencies within Eastern San Joaquin County have existing water rights and contracts that cannot be fully utilized for a variety of factors including supply reliability and infrastructure limitations. The following section describes methods to maximize the use of existing supplies. Re-operation of Existing Facilities The re-operation of existing reservoirs is the intentional drawdown of stored water below the minimum capacity required for flood control purposes. In the context of a conjunctive use program, reservoir re-operation potentially utilizes a reservoir’s carryover storage for groundwater recharge allowing for greater flood control capacity and a reduction in the foreseeable frequency of reservoir spills. Changes in the mode of operation could detrimentally affect other reservoir benefits such as hydropower, water supply, temperature control, and recreation. These impacts can vary the reservoirs ability to be re-operated for increased water supply benefits. In-Basin Water Transfers and Purchases Similar to water transfers from out-of-basin entities, agencies with extensive surface water rights could make water available to other agencies with limited water rights overlying more depressed groundwater levels within Eastern San Joaquin County. Additional investments in infrastructure resulting in increased efficiency could facilitate the transfer or sale of water. In order to avoid the loss of water rights through non-use, water districts and agencies could transfer their rights to other in-basin users. Examples of in-basin water transfer include purchases by the City of Tracy from the West Side and Banta-Carbona Irrigation Districts and by the City of Stockton from SSJID/OID. 4.1.2 Groundwater Recharge Options In 2001 SEWD, in conjunction with the USACE and other local sponsors, completed the Farmington Groundwater Recharge/Seasonal Habitat Study. This Study explored the feasibility of groundwater recharge methods in the context of San Joaquin County’s available surface water supplies and availabilities. The Study explores the benefits and drawbacks of the various methods used to recharge groundwater including detailed cost comparisons. The groundwater recharge methods are discussed below and summarized in Table 4-1. 4.1.2.1 Direct Recharge to Groundwater Field Flooding Field flooding consists of ponding surface water on seasonally fallowed agricultural areas in the late fall, winter, and early spring months for the purpose of recharging the groundwater Basin. In general this option could be used in fields with permeable soils and with little or no vertical impediments. Very few minor site preparations are necessary to percolate substantial amounts of water, making this method economical. Recharge efficiencies can also be increased with the addition of internal berms and check structures creating recharge cells for the purpose of