Miami-Dade’s Root Cause Analysis Reduces SSOs

The Miami-Dade Water and Sewer Department (WASD) is the largest water and sewer utility in the southeastern United States and serves nearly 2.3 million residents and thousands of visitors on a daily basis. The collection system totals nearly 6,300 miles of pipelines, 1,038 pump stations and transports flow to three regional wastewater treatment plants.With a subtropical climate averaging 60 inches of rainfall a year, a relative flat service area with a maximum elevation of 23 feet above mean sea level (MSL), and seasonally high groundwater levels from 3 feet above MSL along the coast to 7 feet above MSL inland, WASD faces significant challenges in controlling infiltration and inflow (I/I) entering the system and in preventing sanitary sewer overflows (SSOs) exiting the system.WASD has been able to reduce SSOs successfully over the years to a historic low of approximately 2 per 100 miles between 2001 and 2004, before starting an upward trend in 2005 and 2006, and again trending down to the 2 per 100 mile average low. To break the 2 per 100 miles benchmark measure low and reduce SSOs even further, WASD has developed a formal Root Cause Analysis (RCA) program.WASD’s on-going RCA program features a monthly review of each SSO event during the previous month and a consensus decision-making activity to define additional corrective actions to prevent SSO recurrence. The purpose of this presentation is to:Detail the information technology (IT) tools developed by the Department to provide useful data on each SSO and all infrastructure assets associated with the each SSO occurrence (For the paper example screen shots of the ASP.NET Web application model that connects to the central Structured Query Language (SQL) Server Spill database to read spill data, to present spill data to users and to update spill data based on users input during the RCA reviews);Describe the monthly RCA meetings and decision-making processes, which involve multiple WASD sections as well as multiple County departments (specifically the Miami-Dade Department of Regulatory and Economic Resources – Division of Environmental Resources Management (RER-DERM)), to define additional corrective actions to prevent recurrence;Provide specific examples of the types of successful corrective actions and how those actions are tracked; andDocument the SSO reductions achieved.The RCA has benefited WASD, and is expected to benefit other utilities facing the need to prevent SSOs, by providing examples and lessons learned from WASD’s experience in reducing SSOs.In developing this formalized RCA process, WASD managers, supervisors and field crews have learned how important it is to review individual SSO occurrences in an environment where all previous SSO records in the area and for that asset type, all asset O&M and repair history is available for review, and where O&M managers and supervisors are openly communicating about problems and obstacles. The ability to quickly identify instances of repeat SSOs related to specific assets such as force mains, which may have quite different SSO addresses for individual SSO events, is crucial to recognizing common elements that contributed to individual SSO events so that the true cause of the SSO can be corrected and future similar SSOs prevented. WASD has been able to move from addressing symptoms to solving problems in a cooperative and effective manner.The IT tools used to facilitate these data intensive RCA meetings include ASP.NET Web application modules that connect to the central SQL Server Spill database to read SSO tracking records and acquire data from Enterprise Asset Management System (EAMS) work order management asset databases. We will show screen shots of how the data can be pulled in a live environment and allow real-time decision making.The audience will gain an appreciation for the need to investigate underlying causes of SSO events rather than continually responding to symptoms for true SSO prevention and reduction. The audience will further learn of specific examples of root cause solutions that have been successfully applied within WASD’s collection system.