The TRWD 108 in. Line J: Lessons Learned from the IPL Prototype Project

Tarrant Regional Water District (TRWD) and Dallas Water Utilities (DWU) have been in the preliminary and final design stages for the Integrated Pipeline Project (IPL) since 2008. The $2.3 billion IPL is a joint project between Dallas and TRWD and will include 150 miles of pipeline from Lake Palestine to Lake Benbrook. The Line J, Section 1 (LJS1) project is being built for TRWD to supply water to a new hydroelectric generation facility and to meet demands at the Lake Arlington delivery point. An opportunity presented itself to use the LJS1 project as a prototype for the IPL project because the project elements are similar. LJS1 utilizes the same design standards and construction methods that are proposed for the IPL project, so that the lessons learned could be applied to the IPL. The objectives of the LJS1 project included the following: to test the use of on-site mixed controlled low strength materials (CLSM) for the IPL; to test the quality of factory-spun cement mortar lining for 108-in. steel pipeline by multiple pipe manufacturers; to test the design standards (design criteria, specifications, and details) for the IPL program; to evaluate the sustainability of alternate construction methods and materials and apply for an Envision rating; to test the use of real-time GIS as-built systems; to evaluate and recommend improvements for constructability, risk allocation, and contract documents; and to provide a dedicated pipeline for the proposed hydroelectric generation facility and alleviate a bottleneck in capacity of the existing system to meet one of its demands. The LJS1 project includes 12,000 ft of 108-in. diameter steel pipeline, with a construction cost of $19 million. Project completion is scheduled for early 2014. The construction manager at risk (CMAR) delivery method is being used with several bid packages for pipe, valves, tunnels, pipe installation, and tie-in sections. This paper describes the lessons learned for the design and construction phases, with an emphasis on CLSM performance and constructability. Additional topics include pipe manufacturing from four suppliers, the CMAR delivery method, GIS as-builds, and sustainability.