North Texas Municipal Water District
East Fork Wetland Project
The North Texas Municipal Water District (NTMWD) is meeting a pressing need for water with a unique and natural solution. In Kaufman County, plants, not machinery cleanse river water as it flows through lush man-made wetlands. Using this organic process, the wetlands help quench a thirst for water that is growing on a massive scale.
The NTMWD area population is projected to increase from 1.5 million people to 3.5 million people by 2050. The demand for water will be like adding the equivalent of one Lake Lavon every decade for 50 years. Traditional conservation methods alone will not meet future needs, especially with the population projections for the region. Most other options are complicated and costly. The East Fork Wetland Project is the exception and increases the district's water supply by 40%, plus it keeps water bills lower than other options with the benefit of enhancing the environment. The East Fork of the Trinity River plays a key role in boosting the region's water supply by billions of gallons.
Representing the largest project in Texas using reclaimed water to augment a surface water supply source, The East Fork Wetland Project provides the North Texas Municipal Water District (NTMWD) with over 102,000 acre-feet of water per year – this is the same capacity of water supplied by Lake Lavon. Completed in 2009, this project consists of diverting water from the East Fork of the Trinity River and polishing the water in one of the largest constructed wetlands in the country (1,840 acres). After passage through the wetland, the water is pumped through an 84” pipeline, 43 miles north of the wetland site to Lake Lavon for storage, blending and water supply use.
The East Fork Wetland Project includes six major components:
Diversion Pump Station to take water from the East Fork of the Trinity River
1,840 acre constructed wetland provides polishing treatment of the diverted East Fork water
Conveyance Pump Station pumps the polished water to Lake Lavon
Electrical substation provides power for the conveyance pump station
43 miles of 84-inch diameter conveyance pipeline starting near Crandall, Texas and extending through Kaufman, Rockwall, and Collin counties transfers water from the wetland to Lake Lavon
The John Bunker Sands Wetland Center provides educational opportunities
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 full scale wetland, completed in 2009.
The construction cost of the The East Fork Wetland Project was $280 million.
NTMWD East Fork Project.pdf
The East Fork Wetland Project operation involves diverting water from the East Fork of the Trinity River into the constructed wetland via the Diversion Pump Station. The amount of water that may be diverted can be up to the amount of return flows that are actually discharged into the East Fork. A determination is made each day by the NTMWD whether or not all or a portion of the return flows can be diverted to the wetland and still maintain the minimum flow of 26 cubic foot per second (cfs) in the East Fork. NTMWD is required to leave the greater of 26 cfs or 30% of the local basin return flows in the river, and the diversions have to be adjusted to allow the greater condition to be bypassed downstream. Two other conditions exist when diversions from the East Fork will not be supplied to Lake Lavon. If Lake Lavon is full and imported water equals NTMWD's diversion from Lake Lavon for the month, the East Fork Wetland Project water will cease to be imported. Also, during the days when Lake Ray Hubbard is full and spilling, the East Fork Wetland Project water will not be imported to Lake Lavon on the day or days that spilling is taking place.
The constructed wetland selected by North Texas Municipal Water District (NTMWD) for polishing treatment of the East Fork water provides multiple benefits:
Removes numerous constituents from the water, resulting in an improved water quality
Provides wildlife habitat that is a major environmental benefit
Provides educational benefits
Provides recreational benefits.
Improving water quality is the major purpose for the East Fork Wetland Project, however, providing the other benefits gains support of the public, environmental groups, and regulatory entities. Gaining this support has been important in obtaining the various permits required for the project.
Treatment Process Description
The constructed wetland treatment process includes sedimentation basins and the wetland cells
Sedimentation basins serve to remove the suspended solids that are in the water diverted from the East Fork of the Trinity River
Constructed wetland cells serve to remove numerous constituents for the water that is achieved by the aquatic plants, bacteria, and physical removal processes.
Wetland Construction Approach
In order to expedite the ability of the wetland to provide treatment as soon as possible, the NTMWD adopted an approach to construct a nursery to grow and propagate aquatic plants starting in 2004. The first nursery, 20 acres in size, was used to provide plant stock of selected emergent wetland species. These plants were then transplanted into a 200-acre second-phase nursery, completed in 2006. The plants from this second-phase nursery were used to provide over 1.6 million plants for the full-scale wetland, completed in 2009. The wetland was planted with more than 20 species of plants. It is important to provide a diversity of plants to achieve the treatment required. Providing a diversity of plants is also beneficial to the wildlife.