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Section 5 <br />As a part of the DMBI project and the Proposed Project, OCWD would continue <br />monitoring groundwater quality at wells SAR-10 and SAR-11 1 and the new <br />monitoring well to be constructed. The groundwater quality monitoring program <br />would include meta9s, major ions, nutrients, field parameters, and Title 22 <br />organics. The data from the groundwater quality monitoring program would be <br />reviewed by0CWD to ensure that operation of the injection wells does not <br />adversely impact groundwater quality. Additionally, data from the Proposed <br />Project would be reviewed annually with the Independent Advisory Panel <br />established by the National Water Research Institute for the Groundwater <br />Replenishment System, <br />Groundwater Quality-Buffer Area Analysis <br />Current State of California's regulations regarding Groundwater Replenishment <br />Reuse Projects (GRRPs), such as OCWD GWRS, were made final by the <br />California Department of Public Health and formally adopted in 2014. <br />Immediately thereafter, the Drinking Water Division (DDW) responsible for <br />developing the GRRP regulations was transferred from CDPH to the State Water <br />Resources Control Board (SWRCB). The GRRP regulations require a minimum <br />subsurface response retention time (RRT) of two months for Full Advanced <br />Treatment (FAT) projects, along with pathogen log-removal standards that Could <br />require additional subsurface residence time. These RRT requirements call for <br />establishing both primary and secondary boundaries (i.e,, buffer areas); the <br />primary boundary is the traditional area in which the construction of new drinking <br />water wells would be restricted, while the secondary boundary is a zone of <br />potential controlled potable well construction, within which the operation of future <br />new well could extend otherwise materially affect the primary boundary, thereby <br />requiring further study and potential mitigating activities prior to potable well <br />construction. <br />A three-month primary buffer area was derived using the Talbert Gap Barrier <br />Model. This is based on CDPH's prior approval of a three-month primary buffer <br />for the recharge of GWRS water in the OCWD Anaheim Forebay. In order to <br />estimate the shortest residence time to an active drinking water well and the <br />farthest estimated extent of the 3-month buffer area under potential future <br />injection conditions, a model simulation period was selected from November <br />2011 to June 2012, This period was selected based on an examination of <br />historical groundwater levels since 2008 that represented a period during which <br />the groundwater gradient was calculated to be steepest from the Mid Basin <br />injection project area toward the nearest drinking water production wells, thereby <br />causi:ng the most rapid groundwater flow velocities. <br />Mid Basin Centennial Park2j5-CrZOLSProject Final EIR 5-114 <br />