Predicting the Location and Duration of Transient Induced Low or Negative Pressures within a Large Water Distribution System

Surge modeling is a tool used by engineers and utility owners in determining the surge pressures or transients that may result from routine pump and valve operations. Recent surge modeling work has focused on low and/or negative pressures within water distribution systems and how those occurrences could lead to intrusions. Effective surge modeling is needed in order to determine if the intrusion potential exists and what mitigation is needed to prevent intrusions. This work focuses on the generally unexplored area of using surge models to predict the location and duration of transient induced low and/or negative pressures within complex water distribution systems. The studied system serves 350,000 people in the southeast United States, has 65 MGD of pumping capacity at two treatment plants, over 1500 miles of main and 12 storage tanks. This work focuses on the correlation between field data and the surge model using the author's operational knowledge of the system, access to realtime SCADA data, and different celerity (or `wave speed') values. This work traces the steps taken by the author to locate areas within the system that experienced transient induced low and/or negative pressure. Additional work was done to estimate the experimental error in field measurements of celerity using commercially available equipment, and to examine methods for reducing this error.