Managing Your Infrastructure’s Mid-Life Crisis: Strategic Pipeline Renewal for Distribution Mains

The challenges of managing buried water infrastructure has been well documented via numerous outlets, including AWWA, ASCE and the EPA. As infrastructure continues to age, with pipelines reaching and exceeding their design life, utility owners face significant challenges in providing reliable service to their customers. Despite the operational and financial challenges facing utilities today in managing their buried infrastructure, Howard County, MD, has successfully stayed at the forefront of the industry for innovative and responsible approaches to pipeline management. This proactive philosophy led them to initiate a multi-phase study to determine the condition of water mains within one of their oldest residential areas, the Village of Wilde Lake, where the pipelines date back to 1967. The County was seeking to maximize the life of the water mains, while also minimizing the financial and logistical impacts to the community while continuing to maintain a high level of service. During Phase I of the study, a countywide risk assessment strategy was established to prioritize and plan subsequent condition assessment and renewal activities for 88,000 feet of cast iron and ductile iron pipe ranging in size from 6 to 12-inches in diameter. The data collected during these assessments was used to establish a renewal and management strategy for the area. Trenchless renewal for large diameter water mains has been used for decades; however, there are several emerging technologies for renewal of distribution mains that have proven to be an effective alternative to full replacement. Given that more than 90% of their 1,000 miles of buried water pipes are distribution mains, the County was eager to pilot some of these techniques, as full replacement of their aging distribution mains would come at a significant cost and disruption to the community. As part of Phase 2, several rehabilitation technologies were evaluated, including CIPP, pipe bursting, sliplining, spray-on lining, CFRP repairs, and internal repair sleeves. Ultimately, two technologies were selected for piloting (CIPP and pipe bursting) on the distribution mains and successfully implemented as part of Phase 3. This paper will cover the County’s emerging holistic 3-phase approach to managing their distribution mains, including the prioritization and condition assessment phase, renewal evaluation phase and rehabilitation implementation for an area representative of their full distribution system, with a focus on the emerging renewal technology selection.