Challenges in Completing a Large Diameter Water Transmission Pipeline

In 2002, the North Texas Municipal Water District (NTMWD) began installing a large-diameter pipeline in the northern end of their service area to meet the growing demands of the North Texas area. The project name was the Allen/Plano/Frisco/McKinney Pipeline (APFM). To meet the population growth and projected demands of NTMWD's customers, the entire pipeline would need to be in service in 2010. This pipeline was planned as a 20-mile pipeline consisting of 72- to 84-inch diameter piping. The pipeline was also planned to run through some of the most congested and active construction areas in the North Texas area. For design and construction reasons, the project was broken into four separate pipeline segments to be done in succession. As of 2007, three of the four segments were completed and in service supplying needed capacity to many of NTMWD's growing customers. In 2008, the planning and design began for the fourth and final phase of the pipeline. This was the southernmost section that would tie to the NTMWD treatment plant and high-service pump station. This last segment was approximately five to six miles and was planned as an 84-inch diameter pipeline. The pipeline route would start at an existing connection to the third segment of the APFM Pipeline in the Town of Lucas, and continue south and east to the NTMWD treatment facility where it would tie into an existing high-service pump station discharge header. Along this projected route were multiple types of land usage areas, including large sections of U.S. Army Corp of Engineers (USACE) property. NTMWD's facilities border the southern side of Lavon Lake in Wylie, Texas. The lake is a USACE lake and, to bring the pipeline into the NTMWD facilities, the pipeline would almost certainly have to cross USACE property. This, along with some of the active construction and the various congested areas that the pipeline would need to cross, posed many different planning and design difficulties when developing the preliminary and final design of the final section of the APFM Pipeline. The proposed paper will detail the preliminary and final design problems encountered by routing a minimum 84-inch diameter pipeline through rural, urban, and USACE property, along with the additional effort that was needed to acquire the necessary land to construct the large-diameter pipeline. The planning and execution of the design and construction of the pipeline had many different aspects and parameters that had to be addressed throughout the process that will also be discussed throughout the paper.