AWWA RSP64399

A key component for developing a pipeline assessment program using Geographic Information System (GIS) tools is the use of accurate and complete data. However, for a variety of reasons, these data may be missing or incomplete. Having a large percentage of missing data can significantly hamper (or pose a significant challenge to) the condition assessment process. Among all pipeline characteristics included in a pipeline GIS database (geodatabase), age, diameter, and material are the most important. This paper discusses the approach and assumptions used to account for these missing data for a large metropolitan water distribution system in order to conduct a pipeline condition assessment, predict trends, estimate economic lives, develop a reinvestment budget and prioritize pipeline replacement or rehabilitation projects. A primary component of pipeline condition assessments is the evaluation of historical main break records. These records are often maintained separately from the GIS pipeline data and correlation of the break data to pipeline data presents another challenge. Spatially locating main break repairs to a pipeline inventory has limitations due to possible errors in the main break repair address or other unforeseen circumstances. This paper also presents GIS techniques and quality control checks that were used to develop a database of high confidence main breaks and provide an accurate characterization of the condition of the existing system. Includes table, figures.