Prioritizing Water Main Renewals: Case Study of the Denver Water System

Abstract

The condition of a water distribution system has strong correlations with community health and economic development. However, studies indicate an urgent need to upgrade the nation’s aging and deteriorating distribution systems if they are to continue to provide customers with reliable, high-quality, and affordable water supplies. In response, utility providers are developing a variety of scientific approaches to identify failure-prone pipes and prioritize their renewal. This paper presents a tool used to assist Denver Water with its pipe renewal decisions. Rather than attempting to measure structural deterioration of each pipe within the system, the model uses a performance-based approach to estimate the present and future condition of each pipe from routine pipe inventory and break record data. Aside from using readily available data, the performance-based approach incorporates site-specific parameters and avoids the need for high levels of technical expertise required to calibrate and verify below-ground parameters common to physical-based models. Building on the Pipe Failure Assessment Model (PFAM) originally developed at Colorado State University, the updated tool has several features that better address the industry’s data limitations and complement Denver Water’s existing planning tools. Whereas this paper addresses model development and testing using data provided by Denver Water, a follow-up paper will report on the model’s overall performance after one year of use and any recommendations proposed by the utility to enhance its usefulness.