Overcoming the Challenges of Large Diameter Water Project in North Texas via CMAR Delivery Method

The Bois d’Arc Lake Project is an estimated $1.6 billion water delivery program to expand North Texas Municipal Water District’s (NTMWD) regional water system. This program consists of numerous individual components that must be orchestrated concurrently to collect, treat, and transport water from the first major reservoir to be built in Texas in nearly 30 years to 80 different North Texas communities. The major components consist of a reservoir dam and raw water intake, raw water pump station, raw water conveyance pipeline, various roadway, and bridge improvements, environmental mitigation, terminal storage reservoir, high service pump station, water treatment plant, and treated water pipeline. Garney Construction was awarded Construction Manager at Risk (CMAR) services for two critical components of this project—the water treatment plant as well as the raw and treated water pipelines. Garney is responsible for the entirety of the raw and treated water pipelines, including preconstruction design services, coordination, scheduling, estimating, management, oversight, portions of construction, and cost management. The pipelines portion of this project will be constructed in two phases. The first phase of work consists of approximately 35 mi of 90-in. transmission main to transfer water from the newly constructed reservoir to a terminal storage reservoir in Leonard, Texas. This portion of the alignment is contained within Fannin County. The second phase of work consists of approximately 25 mi of 84-in. pipeline to convey potable water from the newly constructed Leonard Water Treatment Plant to a terminal connection near McKinney, TX, within NTMWD’s existing regional water system. This portion of the alignment extends across Fannin and Collin County as well as a small section of Hunt County. The CMAR delivery method is an ideal selection for a project of this magnitude. By virtue of the shear distance (approximately 60 mi), there are a multitude of challenges that vary along the course of the pipeline alignment. The northern portion of the raw water alignment is predominantly rural in nature, while the southern portion of the treated water alignment is more populated. Consequently, the diversity from one end of the project to the other poses many different and unique types of challenges. Having a competent and qualified CMAR contractor engaged early in the design aids not only to mitigate those challenges, but also to facilitate advancement of design without sacrificing completion milestones. Unlike the traditional design-bid-build delivery method, the CMAR delivery method allows for participation during the design phase. Being a participant in the design phase empowers the CMAR to offer construability suggestions, review public relations concerns, and develop initial construction sequencing of work. Furthermore, the CMAR is afforded the opportunity to procure long lead materials as well as execute construction contracts prior to final design. Ultimately, this delivery method allows the CMAR to overcome many of the schedule and design constraints that are typical of a traditional delivery method.