Mr. Jim Frisinger
U.S. Army Corps of Engineers
Fort Worth District
P.O. Box 17300
819 Taylor Street
Fort Worth, Texas 76102-300
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The Dallas Floodway Extension (DFE) Project is located in Dallas, Texas, along the Trinity River beginning where the Dallas Floodway ends (at the abandoned Atchison, Topeka and Santa Fe trestle) and extending downstream to the area where IH-20 and Dowdy Ferry Road intersect. It is a complex project in cooperation and partnership with multiple units of local, state and federal government. It addresses a number of regional concerns, although reducing flood risk for the citizens of Dallas remains the cornerstone of this multi-faceted effort.
The U.S. Army Corps of Engineers has oversight responsibility for all activities within the federally authorized Dallas Floodway System. The Corps' Fort Worth District is a lead actor in some of the projects, such as the Dallas Floodway Extension Project here. In other projects within the confines of the Dallas Floodway Extension Project listed below, the Corps plays a smaller supporting role.
This Corps project is focused on three of five inter-related components: flood protection, ecosystem restoration and recreation in partnership with the City of Dallas, which is the Dallas Floodway Extension's local sponsor.
The Corps also has some role, but not a lead role, in two other major components: transportation and community/economic development.
Public safety is the No. 1 priority in the Corps' Levee Safety Program. The DFE Project, now in the construction phase, is one of two adjacent Fort Worth District projects on the Trinity River designed to reduce flood risk for the citizens of Dallas. The other project, the Dallas Floodway Project, is in a Feasibility Study/Draft Environmental Impact Statement phase and is also in partnership with the City of Dallas, the non-federal sponsor. The Corps and the City of Dallas share the responsibility of public safety and both are committed to flood risk management. Each project has its own web section accessed from the Fort Worth District home page. The Corps also provides public access to a National Levee Database providing more information on Dallas levees.
The DFE Project area experienced property damages during May 1989 and May 1990 floods. A re-evaluation of a previously authorized project was conducted and a project was identified to provide reduce risk to the Standard Project Flood standard for about 2,550 structures within the project area. The project will also increase the level of protection to the existing Dallas Floodway, just upstream, providing an additional $6.7 million in average annual benefits to about 10,000 structures. Completion of the DFE will reduce water surface elevations within the existing Dallas Floodway, thereby reducing the risk to life and safety for those protected by the existing levees.
This is being accomplished by replacement of more than 200 acres of bottomland forest with new wetland and grassland habitat. This bottomland forest loss will in turn be mitigated elsewhere in the Great Trinity Forest by acquisition of large tracts totaling more than a thousand acres – some of it abandoned farmland – that will be returned to or managed as bottomland hardwood forest.
The DFE, authorized by the Flood Control Act of 1965, was initiated in December 2001 to construct the Chain of Wetlands, the Cadillac Heights and Lamar Levees, and recreation features immediately downstream of the existing Dallas Floodway.
Key Dallas Floodway Expansion Project Details
- A Chain of Wetlands is being built that will be 3.7 miles long and have an average width of 600 feet. It will add overbank flowage capacity for flood waters along the west side of the Trinity River from the north end of Cadillac Heights to Loop 12 just north of Lemmon Lake. The Chain of Wetlands is designed to help speed the flow of floodwaters away from the Dallas Floodway down and through the upper reaches of the Great Trinity Forest. This lowers the flood risk for the city.
- The ecosystem restoration component follows an adaptive management approach led by the Corps' Engineer Research Development Center's Lewisville Aquatic Ecosystem Research Facility. It is building 271 acres of improved habitat as follows: 123 acres of emergent wetlands, 45 acres of open water and 102 acres of grasslands. Plants to populate the wetlands are cultured at the Lewisville facility. Cell D was constructed in 2004 and plantings and ecosystem management began in 2005. Among the Lower Chain of Wetlands (cells labeled D through G), the last was excavated in 2008. Design efforts for an Upper Chain of Wetlands (cells A through C) continues.
- About 1,179 acres of environmental mitigation land is being acquired within the floodplain's Great Trinity Forest. The mitigation plan includes acquisition, improvement and management of 926 acres of bottomland hardwood. It also includes acquisition of 253 acres of mixed grassland/forbland, of which 223 acres would be converted (planted and managed) to bottomland hardwood forest; the remaining 30 acres would be managed as grassland.
- To protect the integrity of the IH-45 overpass, the Trinity River channel was moved laterally about 350 feet and centered between a 320-foot span.
- A new Cadillac Heights Levee is planned to protect this neighborhood (west side of river) for a distance of 2.3 miles and provide Standard Project Flood risk management at the 800-year level. It will connect with the Central Waste Water Treatment Plant Levee.
- Levee improvements at the Central Waste Water Treatment Plant will manage risk to the 500-year-flood level to the Dallas facility.
- Planned levee improvements will provide an 800-year level of protection for the Rochester Park Levee.
- A new Lamar Levee will be constructed along Lamar Street (east side of river) for a distance of 2.9 miles. It is to reduce risk down to the 800-year standard and will connect to the existing Rochester Park Levee.
- Thirty-one miles of recreational trails will be built. The recreation plan will create linkages between existing recreational areas and public open space areas and will include 18 miles of concrete trail, 8.5 miles of natural surface equestrian trails and 5 miles of natural surface nature trails. Seven access areas are planned. Some of this multi-stage program is in the construction phase.