Flow Science performed a hydraulic and transient analysis of the City of Irving’s Lake Chapman Water Supply Project. The 84 mile long system will ultimately consist of five pump stations delivering up to 225 mgd along pipelines ranging in diameter from 84 inches to 48-inches.Due to site constraints and existing vacuum valves on the pipelines, additional vacuum valves were placed along the pipelines and some were retrofitted for slow closing to prevent line-fill slam.