Zone 7 Water Agency faces compounding challenges in providing reliable water to more than a quarter million people in the San Francisco Bay Area. While demands in the Tri-Valley region are expected to grow 30% over the next 25 years, Zone 7's supplies, like many California water suppliers, are challenged by long-term declines in State Water Project reliability, evolving regulatory constraints affecting Sacramento-San Joaquin River Delta exports and local groundwater operations, and increasing hydrologic variability driven by climate change. In response, the Agency is proactively evaluating investments in new supply sources, conveyance, and storage infrastructure to meet its long-term reliability goals.

To support this effort, Zone 7 has developed a comprehensive Water Supply Portfolio Model in RiverWare, which represents their integrated system of imported and local supplies, storage facilities, and demands. The Model builds on RiverWare's rule-based simulation framework and incorporates a flexible prioritization framework that allows Zone 7 to rapidly test new water supply portfolios and system operations strategies with minimal revisions to the RPL ruleset.

The Model also incorporates hydrologic uncertainty via an index sequential approach allowing for preservation of hydrologic persistence and representation of multi-year drought dynamics that drive system risk. The model is further integrated into a PowerBI-based, user-friendly visualization platform that enables decision-makers to interactively explore performance metrics, compare portfolios, and communicate results.

This presentation highlights how Zone 7 is leveraging RiverWare within a larger decision-support framework to evaluate supply diversification strategies, optimize system operations, guide capital investment planning, and ultimately support actionable insights for water management in an uncertain future.