07-724. Intent To Prepare a Draft Supplement No. 1 to the Final Environmental Impact Statement for the Upper Trinity River, Central City Project, Fort Worth, TX

AGENCY:

Department of the Army, U.S. Army Corps of Engineers, DoD.

ACTION:

Notice of intent.

SUMMARY:

Section 116 of Pub. L. 108-447, dated December 8, 2004, authorized the U.S. Army Corps of Engineers' (Corps) participation in construction of the Central City project. A Final Environmental Impact Statement (FEIS) was completed for the Central City Project in Janauary 2006. A Record of Decision (ROD) recommending the Community-Based Alternative and determining it was technically sound and environmentally acceptable was signed by the Assistant Secretary of the Army for Civil Works (ASA (CW)) on April 7, 2006. An Interim Feasibility Report with Integrated Environmental Assessment (with signed Finding of No Significant Impact) for the Riverside Oxbow Project was approved by the Chief of Engineers on May 29, 2003. An addendum, dated April 2005, was prepared to address comments from the ASA (CW); however, neither construction funding nor authority for implementation of this project has been provided by Congress to date.

By letter dated June 22, 2006, the City of Fort Worth requested the Corps to evaluate the potential benefits of merging the Central City Project with the Riverside Oxbow project. They identified potential benefits including greater opportunity for valley storage requirements, increased restoration opportunities, and cost savings. After an initial evaluation, the Corps determined that alternative areas along the West Fork of the Trinity River including areas within the Riverside Oxbow project had the potential to provide the required hydraulic mitigation, provide comparable ecosystem restoration outputs, reduce habitat mitigation requirements, and lower overall project costs.

These potential modifications to the projects may be substantial and a supplement to the Central City environmental impact statement should be prepared concurrently with a more detailed analysis. Therefore, this Notice of Intent to prepare Supplement No. 1 to the FEIS for the Central City project is being issued in accordance with the Council on Environmental Quality's NEPA implementing regulations at 40 CFR Parts 1500-1508.

FOR FURTHER INFORMATION CONTACT:

Questions and scoping comments pertaining to this analysis and Draft Supplement to the EIS should be directed to Mr. Saji Puthenpurayel, Project Manager, CESWF-EC-D, U.S. Army Corps of Engineers, Fort Worth District, P.O. Box 17300, Fort Worth, TX 76102-0300, [phone].

SUPPLEMENTARY INFORMATION:

The Central City project as authorized includes a flood bypass channel and flood gates to divert flood flows around a segment of the existing Trinity River channel adjacent to downtown Fort Worth, Samuels Avenue Dam to create an interior water feature, and hydraulic and ecological mitigation areas. The bypass channel is approximately 8,400 feet long, 300-400 feet wide, and would be approximately 30 feet below the existing grade. The bypass channel would begin at the Clear Fork downstream of West Seventh Street, interest the West Fork approximately 2,600 feet upstream of the existing confluence with the Clear Fork, and continue to the northeast terminating at the West Fork about 8,500 feet downstream of the existing confluence. The Corps component of the Central City Project was authorized for construction by Section 116 of Public Law 108-447, dated December 8, 2004. Under that authority, Corps participation is limited to $110 million with a total project cost $220 million for that portion of the infrastructure plan in which the Corps can participate.

Without hydraulic mitigation, the Central City project would result in a loss of valley storage due to the bypass channel being shorter and more efficient than the existing river channel. Valley storage sites are included in the existing authorized plan to compensate for this potential loss of storage. Four areas would provide the required valley storage; along the West Fork of the Trinity River upstream of the bypass channel (Riverbend/Rockwood), adjacent to University Drive, in the vicinity of the Samuels Avenue Dam, and slightly downstream of the proposed dam site in proximity to Riverside Park. Construction of the bypass channel and associated valley storage sites would not increase downstream water surface elevations or downstream flow.

Reestablishment of vegetation and habitat at the Riverbend/Rockwood site following construction activities were included in the authorized plan, partially for mitigation of project impacts to wetland, riparian, and terrestrial resources and partially for ecosystem restoration. Additional habitat mitigation measures were included along Ham Branch, a tributary of the West Fork of the Trinity River, which enters the system a short distance downstream of Highway 121. Approximately 305 feet of the existing channel would be relocated to provide adequate width for riparian forest development and existing riparian habitat would be improved along the remainder of the channel.

The Riverside Oxbow project area is adjacent to and immediately downstream of the Central City Project. The focus of the project is to restore the ecological integrity of aquatic and riparian systems along a portion of the natural Trinity River channel that was severed by construction of a realignment and enlargement of the West Fork of the Trinity River channel by non-Federal interests. The Interim Feasibility Report recommends implementation of the Locally Preferred Plan, which consists of the National Ecosystem Restoration (NER) Plan along with additional local features. The NER plan for the Riverside Oxbow will restore the biological integrity of the wetland and bottomland hardwood communities through a combination of measures directed at either specific habitat types or specific problems within the existing ecosystem.

The City's request to merge these projects recognized that each project is moving forward independently but they are located adjacent to one another. The City and the Tarrant Regional Water District expressed their opinion that based on their adjacency, there might be merit in combining the two projects. In their letter, the City of Forth Worth identified potential benefits of combining the two projects that would not be achieved if they proceed independently. These potential benefits included greater flexibility in selecting sites for the required valley storage mitigation, opportunity to increase restoration benefits, and cost savings.

In addition, during detailed design investigations it was determined that alternative locations of the proposed Samuel Avenue Dam should be evaluated due to geotechnical considerations. The amount of aquatic habitat impacted in marine and Lebow Creeks is affected by the location of Samuels Avenue Dam and will be considered during further site analysis.

In response to the City's letter request, the corps performed an initial evaluation and determined that alternative areas along the West Fork of the Trinity River including areas within the Riverside Oxbow project had the potential to provide the required hydraulic mitigation, provide comparable ecosystem restoration outputs, reduce habitat mitigation requirements, and lower project costs. Following review of this initial evaluation, Corps Headquarters directed that a detailed analysis be undertaken that evaluates the total hydraulic system including the Central City and Riveside Oxbow project areas. The Corps' approving offices acknowledged that to determine if and how either project should be modified, additional study, reporting, and environmental compliance would be required.

All affected Federal, State, and local agencies, affected Indian tribes, and other interested private local organizations and parties are hereby invited to participate in the development of the Draft SEIS. No Public Meetings have been scheduled at this time, however all agencies and other known interested entities will be informed by public notice to request their comments regarding the potential modifications. Coordination will continue with the U.S. Fish and Wildlife Service and Texas Parks and Wildlife Department in accordance with the Fish and Wildlife Coordination Act. The Texas State Historic Preservation Office will be consulted as required by Section 106 of the National Historic Preservation Act. Potential modifications to the project will also be coordinated with the Texas Council on Environmental Quality to ensure any changes are in compliance with Section 401 of the Clean Water Act.

Dated: February 7, 2007.

Christopher W. Martin,

Colonel, Corps of Engineers, District Engineer.