Evaluation of Groundwater Supply Alternatives Within Bernal Subbasin

REGIONAL GROUNDWATER FACILITIES PROJECT FEASIBILITY STUDY 23 Zone 7 Water Agency December, 2025 screened out and do not advance in the evaluation. Zone 7’s groundwater modeling indicates that all four project alternatives are consistent with the Alt GSP, remaining compliant with sustainability criteria for both groundwater levels and water quality. In addition, LSCE and Zone 7 staff reviewed modeling results conducted by EKI (Appendix G) for this Feasibility Study and concluded that the proposed well development aligns with Zone 7’s basin sustainability objectives. 3. Community & Environmental Impacts This criterion considers how new well facilities located within residential parks may affect nearby residents and the environment. Construction activities are expected to cause short-term impacts such as noise, dust, traffic, and temporary loss of recreational space, while long-term impacts may include visual changes, operational noise, and access restrictions to parks. Alternatives that minimize these impacts and reduce intrusion into community spaces are considered more favorable than those with greater visibility or community disruption. 4. Capital Cost Capital cost reflects the relative initial investment needed to bring each alternative online, including well construction, equipping, pipelines, electrical facilities, and site development. Costs have been estimated in Section 3, and this criterion scores alternatives qualitatively against one another rather than repeating detailed numbers. Lower-cost alternatives are generally more favorable, although higher-cost options may offer added benefits such as improved reliability or other benefits that balance their expense. 5. Water Quality/Treatment Impacts This criterion evaluates the potential for water quality concerns at proposed well sites that may require current or future treatment. Zone 7’s PFAS transport model, which accounted for long-term effects of the large PFAS footprint to the east, indicates that projected concentrations remain below detection limits over a 20-year period. While this modeling provides confidence that PFAS migration and concentrations at all project alternative well sites will not constrain the alternatives, wells located closer to the existing footprint carry greater long-term uncertainty and possible treatment requirements. Alternatives farther from the footprint are considered less vulnerable and therefore score higher. 6. Implementation Schedule The implementation schedule reflects the anticipated time from project approval to initial water production. For all alternatives, the principal driver is reaching an agreement between Zone 7 and the City on project scope and cost sharing. Once a decision is made, design and construction are expected to take 18 to 30 months, depending on the complexity of the alternative and whether contract structures allow multiple construction crews to work concurrently. Simpler, shorter-duration alternatives score higher, while those with longer or more complex delivery paths score lower. 7. Operational Flexibility & Resilience This criterion measures the ability of each project alternative to perform reliably under varying conditions such as drought, planned and unplanned equipment downtime, or future changes in groundwater quality. Alternatives with multiple wells allow for lead/lag operational flexibility, provide redundancy, and maintain production during maintenance or outages, resulting in higher scores. Single-well alternatives, while simpler, have limited redundancy and are more vulnerable to interruptions.