Record of Decision signing clears major milestone for Dallas Floodway Project
View 2015 Record of Decision, Modified Dallas Floodway Project
FORT WORTH, Texas – The Dallas Floodway Record of Decision has been signed, marking a major milestone in advancing the U.S. Army Corps of Engineers partnership with the city of Dallas in reducing flood risk and supporting the local sponsor’s Balanced Vision Plan.
The proposed $571.6 million project in the federal levee system cuts flood risk, restores river habitat destroyed when the Trinity was first moved and supports the city’s 2,300-acre recreation blueprint, the Balanced Vision Plan, for the floodway. With the approval, the Corps of Engineers is now authorized to participate in the congressional budgeting process to fund the first phase of construction.
Jo-Ellen Darcy, Assistant Secretary of the Army for Civil Works, signed the Record of Decision last week approving two Dallas Floodway documents: the Final Environmental Impact Statement and the Final Feasibility Report. Both are available online: http://www.swf.usace.army.mil/Missions/WaterSustainment/DallasFloodway.aspx
“Today’s approval could not have been achieved without many years of dedicated work by the city of Dallas and Corps staff,” said Lt. Col. W. Neil Craig, acting commander, Fort Worth District. “Life safety is the No. 1 goal of our team. Together we crafted a plan that reduces flood risk for more than the 200,000 Dallas citizens who live and work near the river, and backs the Balanced Vision Plan to create parkland in an urban setting with little open space.”
The two documents Darcy approved evaluated “technical soundness and environmental acceptability’ of the Modified Dallas Floodway Project. It also examined the impact of all projects currently anticipated in this 11-mile corridor, not all part of the MDFP. That includes flood-risk management elements, Interior Drainage Plan pump stations, ecosystem restoration, recreation enhancements and the Trinity Parkway. The documents concluded the end result would increase the acreage and functionality of wetlands and other waters of the U.S. within the Floodway, and that the design impacts on the hydrology and hydraulics of the Trinity River were less than significant. The FEIS was written to accommodate a design that includes both construction of the Parkway -- and another variation with no Parkway built.
The Final Feasibility Report evaluated whether the Recommended Plan of the Modified Dallas Floodway Project met criteria for an authorized Federal project. The report documents the study initiated in response to Section 5141 of the Water Resources Development Act (WRDA) of 2007 as amended by Section 4013, Water Resources Reform and Development Act of 2014. The report was initially approved March 17, 2015, by the Corps of Engineers Director of Civil Works, Steven L. Stockton.
Key elements of the Modified Dallas Floodway Project
- Cost-sharing. The $571.6 million project (FY2015 dollars) will be cost-shared with the city of Dallas as follows: 65 percent Federal, 35 percent city.
- Raising the low spots in the levees. Since Corps construction of the Federal levee system in the late 1950s, there has been some settling of the levee crests below design grade.
- Flattening the levees to 4-1 width-height ratio (a betterment funded 100 percent by the city).
- Modification of the abandoned AT&SF Bridge to remove embankments and piers that impede stormwater passage. This will allow greater flows through the system without overtopping the levees.
- Emergency Action Plan non-structural improvements (Flood Depth Inundation Maps).
- The Interior Drainage Plan implementation: Expansions of Hampton, Baker, Charlie and Delta Pump Stations, building the new Trinity Portland Pump Station, and improvements to the Nobles Branch sump. These improvements will reduce the risk of neighborhood flooding.
- Trinity River relocation (river meander) with ecosystem restoration. About 8 miles of the river would be restored with many new native Texas aquatic and upland plants established. This will increase habitat value that was degraded when the river was moved and channelized in the 1920s.
- Building the 80-acre Corinth Wetlands on the west side between the Corinth Bridge and the Santa Fe Trestle Trail.
Background on the Modified Dallas Floodway Project and other projects in the Trinity corridor
MDFP phasing: The Corps of Engineers will first seek congressional funding for life-safety elements: levee raises and the AT&SF bridge modification. Levee flattening would be accomplished at the same time.
Reducing flood risk: Levee improvements listed above would increase the flow capacity to 254,000 cubic feet per second without overtopping the levees (a risk/frequency of one in 1,500 chance of happening in any given year) to 277,000 cfs (a risk/frequency of one in 2,500 chance of happening in any given year). There is about $14 billion in property (structure and content value) behind the levees.
West Dallas Lake: Soil excavated for the levee raises and 4-1 side slope flattenings would form the initial excavation of the city’s planned lake.
Additional permits: As with most major projects in the Federal levee system, construction by the city will require Section 408 and Section 404 permits. Separate Section 408 (Rivers and Harbors Act) and Section 404 (Clean Water Act) permits will also be required for the Trinity Parkway. The Federal Highway Administration issued its own Final Environmental Impact Statement Record of Decision for the Trinity Parkway earlier this month.
Construction- level design documents: The Corps of Engineers’ has continuing oversight responsibility for all projects within the Dallas Floodway. The city and the Federal Highway Administration will each have to submit construction-level documents with more design details as their individual projects advance.
About the Fort Worth District:
The Fort Worth District, U.S. Army Corps of Engineers was established in 1950. The District is responsible for water resources development in two-thirds of Texas, and design and construction at military installations in Texas and parts of Louisiana and New Mexico. Visit the Fort Worth District Web site at: www.swf.usace.army.mil
and SWF Facebook at: http://www.facebook.com/pages/Fort-Worth-District-US-Army-Corps-of-Engineers/188083711219308