San Antonio Water System Inflow Reduction Manhole Assessment Program – Scouting the Seepage

The San Antonio Water System (SAWS) entered in to a Consent Decree (CD) with the U.S. Environmental Protection Agency (EPA) in June 2013. The CD outlines a program that SAWS would complete to reduce Sanitary Sewer Overflows (SSO) within the SAWS wastewater collection system. In 2014 San Antonio experienced significantly above average rainfall and flooding, which resulted in identified capacity constraints. In efforts to reduce system wide inflow into the wastewater collection system SAWS recommended to implement an Inflow Reduction program. This paper will cover a pilot study of different manufacturer types of manhole lids tested for leakage to identify which performed the best that allowed minimal inflow as well as the logistics of inspecting manholes in SAWS’ creek beds, flood plains and areas in the city prone to flooding. This paper will discuss the design of various inspection forms, databases and development of guidelines for field inspection as well as for assessment and repair recommendations of the field inspection data. The paper will also discuss the goals of each of the inspection programs and how SAWS is inspecting for and reducing inflow in their collection system.