A few weeks prior to the spill, the 24" force main and pump station were taken out of service to isolate a different section of force main pipe (located directly outside of pump station 1 to the West of the Goleta Slough), for repair and a bypass operation was used while repairs took place. This repair was a result of a leak causing exfiltration that GWSD voluntarily notified the Central Coast Regional Water Quality Control Board about. The bypass utilized the District’s back-up 18" force main. The 24" force main was left in ready and working state, but not pressurized, while the bypass was in place. Best practices were used to ensure the force main could safely be brought back into service. When repairs were completed on the evening of February 16th, the 24" force main and pump station were put back into service following GWSD's written procedures.
The District ascertained that the spill began around 8:00 p.m. on the night of February 16th. The spill was discovered at 8:24 a.m. on the morning of Saturday, February 17th when District personnel followed up to check on the pump station and force mains as is standard procedure whenever changes are made to force main operations.
Upon discovery of the spill, GWSD staff immediately took action to stop the flow to the 24" force main and worked urgently to contain the spill. Additionally, District staff activated mutual aid response with Goleta Sanitary District and the City of Santa Barbara to support the containment and clean-up effort. Response urgency was heightened by the forecasted atmospheric river that would bring 3 inches of rain in the coming days.
Post-spill investigation and analysis by both the District and 3rd party engineers revealed external damage to a 12 inch long area of the 24” force main. Because the pipe was well within its projected life span, it is theorized that the damage to the exterior coating was sustained during installation decades earlier, facilitating the external corrosion witnessed on the pipe. Internal and external pipe coating materials are intended to guard against normal corrosion, but the soil conditions near the Goleta Slough are highly corrosive and appear to have contributed to the failure in a way that could not have been anticipated without knowledge of the installation damage.
District staff created improvised containment to prevent the flow of wastewater into a tributary to the Goleta Slough in an effort to minimize impacts to the environment. A sewage vacuum truck collected and disposed of 12 loads of standing wastewater and a dump truck and tractor were deployed to carefully collect and remove solids.
Collaborative corrective actions
Local, county, and state agencies responsible for ensuring proper handling of wastewater have been closely involved in the spill response efforts. Additionally, since Goleta West Sanitary District conveys wastewater near to sensitive wetland areas, agencies with oversight responsibilities over these areas have been involved in evaluating how to prevent future occurrences. GWSD has dedicated itself to responding appropriately and vigorously to ensure incidents like these do not happen in the future.
The state Regional Water Quality Control Board (RWQCB) is the primary oversight agency for spill incidents. GWSD followed all protocols and continues to satisfy agency requirements. By March 1, 2024, the District submitted a certified spill report, and a month later, the District followed up with a technical report. These reports have been updated when warranted by further investigation.
The District arranged for stress testing by certified engineers to verify the integrity of the entire force main pipe repairs before the 24” force main was brought back online on May 1st.
Prior to the spill in February 2024, GWSD was in the process of assessing the condition of its pipes, including the force mains, as part of its Sewer System Management Plan (SSMP). GWSD engaged an engineering firm for this assessment in November 2022. The engineering firm was finalizing its condition assessment into a report at the time of the February 2024 spill. The District then asked the firm to consider the spill event findings and authorized a more extensive condition assessment utilizing Best Available Technology (BAT). The scope of the assessment utilizing BAT included additional field inspections and detailed data collection to provide comprehensive information that was not in the scope of the original assessment. The District expects to have a final condition assessment report in the Winter of 2025, and will use it to inform future rehabilitation and/or replacement efforts. The District anticipates presenting the final report to the District’s Board of Directors for consideration and approval in Winter 2025.