Oceano CSD Water Supply Evaluation

The Oceano CSD (District) has a diverse water supply portfolio it uses to provide drinking water to its service area's residents. This portfolio consists of groundwater from the Santa Maria Valley Groundwater Basin, surface water from Lopez Reservoir and imported water from the State Water Project (SWP). The District has leveraged its water supplies to reliably provide water to its customers during extended droughts and other hydrologic conditions. 

Recent changes to the water supply contracts that the District has for its Lopez and SWP supplies (i.e. Zone 3 Contract Changes and Water Management Tools Amendment) with the San Luis Obispo County Flood Control and Water Conservation District (SLOCFCWCD) provide new opportunities for how the District can manage its water supplies to provide additional water reliability, resiliency against infrastructure failures and cost recovery opportunities. These opportunities, along with potential interest from SWP Subcontractors in purchasing additional “Drought Buffer” SWP water through SLOCFCWCD, and the potential for the District to lose the reliability of the SLOCFCWCD’s “Unsubscribed Allocation” warrant an updated evaluation of the District’s water supply portfolio. 

To assist the District in evaluating these new water supply opportunities, ConfluenceES developed a Water Supply Operations Model (Supply Model) that was utilized to evaluate the District’s water supplies under potential future hydrologic conditions. The findings from the future water supply scenario analysis, which include varying water supply portfolio and hydrology assumptions are intended to help inform the District on potential strategies to leverage its current and/or future water supply portfolio to maximize the benefit of these critical resources for the District. 

The Supply Model operates on an annual time-step and can illustrate how the District can utilize SWP water, Stored SWP water, Lopez Water, Stored Lopez Water and Basin groundwater over varying drought cycles to meet its customer’s water demands. The Supply Model also calculates the volume of water lost to spills at San Luis and Lopez Reservoirs and the potential value of the lost water to help the District identify strategies to maximize revenue recovery through entering into exchange or sales agreements for its water supplies.