East Fork Raw Water Supply Project, North Texas Municipal Water District

Plummer provided design and environmental services, which consisted of diverting an average of 91 mgd from the East Fork of the Trinity River and polishing the water in one of the largest constructed wetlands in the country (2,000 acres). After passage through the wetland, the water is pumped through an 84-inch pipeline 43.5 miles north of the project site to Lavon Lake for storage, blending, and water supply use. A multi-year project, work first began on the constructed wetland in 2004 with the design and construction of the first of two nursery wetlands. The initial nursery, 20 acres in size, was used to provide plant stock of selected emergent wetland species for a 200-acre second-phase nursery. The 200-acre nursery, completed in early 2006, was used to provide over 1.6 million plants for the field-scale wetland that was completed in 2009.

The pipeline route runs through Kaufman, Rockwall, and Collin Counties. A significant challenge was to determine a route that minimized pipe length and static head for the conveyance pump station. Several routes were studied with the use of aerial photography, parcel maps, and digital elevation model (DEM) topographic information to select the preferred pipeline alignment. The pipeline was divided into three pipeline segments—Northern, Central, and Southern—to facilitate a fast-track design and construction schedule. Associated with the northern pipeline segment is the design of the Lavon Lake outfall structure, located on USACE property, which included the challenge of meeting budget and maintenance requirements of the NTMWD and requirements of the USACE.