South Florida Aging Infrastructure: Force Main Condition Assessment

Over the years, many engineering, environmental, and related research organizations placed much study and analysis on drinking water pipelines, whereas metallic wastewater pressure pipelines such as force mains have received less attention yet are also subject to similar deterioration and unanticipated leaks. For many water utilities, the value of buried pipeline assets often exceeds the value of treatment facilities. As pressure pipelines continue to age and deteriorate, unanticipated breaks and resulting emergency repairs are creating an increasing percentage of utilities’ operating budgets. In addition, public inconvenience and repair costs, fines, or sanctions may be imposed for the release of untreated wastewater to the environment. To shift from a reactive to a proactive strategy, many utilities are embarking on programs to assess the condition of buried assets and implement rehabilitation projects to extend the life of the pressure pipelines. To address these challenges, a condition assessment strategy for pressure pipe should include: a progressive inspection process that utilizes broad diagnostic inspection tools among the inventory of pipelines; a risk assessment of each asset that incorporates the likelihood of failure and consequence of failure for each asset; and a qualitative, quantitative, and detailed description and assessment of the condition of each pipe. A tiered approach for deploying inspection equipment focuses on providing the most important data, in the most relevant locations. By focusing specific cost-effective technologies only on the assets where the data is most relevant, unnecessary inspection costs are avoided. This paper will focus on application of a tiered condition assessment approach in a South Florida, particularly in Fort Lauderdale, Florida. South Florida has unique challenges related to wastewater pressure pipe condition assessment, including: many miles of pressure pipe due to flat topography, resulting in higher costs for condition assessment; corrosion due to salt water intrusion; and wastewater pressures are lower than drinking water pressures, which result in fewer applicable condition assessment technologies.