Design, Pipe Material Selection, and Manufacture for the Lake Texoma Outfall Raw Water Pipeline: Genesis of a Fast-Paced Large-Diameter Project

Abstract

The North Texas Municipal Water District (NTMWD) is responsible for supplying raw water to its thirteen member cities that ultimately benefits nearly 2 million people. Water from Lake Texoma, located on the Texas-Oklahoma border, accounts for approximately one quarter of NTMWD’s supply. Restrictions were placed on pumping water out of the Lake due to an infestation of Zebra Mussles in 2009, and a major state-wide drought in 2010 and 2011 resulted in NTMWD facing severe shortages to it water supply. In 2011, an initiative was undertaken to have a new large diameter transmission pipeline built that would bring the Zebra Mussel infested water directly from Lake Texoma into a treatment facility in Wylie, Texas. The resulting design was that of a 50-mile transmission pipeline ranging in diameter from 84-inch through 96-inch which needed to meet demands in Summer 2014. This line had to be built in just over two years, with an aggressive fast-paced design and construction schedule. Failure to successfully meet this schedule-driven project would result in severe impacts to over a million people. The Construction Manager at Risk (CMAR) delivery method for materials and construction procurement was used, along with other non-conventional methods such as direct communication with multiple pipe procurement during design, and releasing pipe manufacturer bid packages with only thirty percent design plans. This paper discusses in detail the means and methods utilized in delivering this large-scale project in the fastest and most efficient manner, design and specification of the pipeline, and pipe material selection from the CMAR Engineer’s perspective. This is followed by details of the submittal and pipe-making processes from a Manufacturer’s perspective on three of the five sections of the pipeline.