Draft Supplemental Environmental Assessment
DRAFT FINDING OF NO SIGNIFICANT IMPACT
SUPPLEMENTAL ENVIRONMENTAL ASSESSMENT
CIVIL WORKS, MINOR SECTION 408 NEPA COMPLIANCE
U.S. ARMY CORPS OF ENGINEERS FORT WORTH DISTRICT
FOR TWO STORM DRAINS (E4 AND W4)
Description of Action. The United States Army Corps of Engineers (USACE) evaluated a proposed 33 U.S.C. Section 408 request for the construction of two outfall structures located on the south bank of the Clear Fork Trinity River, just east of Bryant Irvin Road in Fort Worth,
Texas. These outfall structures are necessary to provide drainage for the NTTA Chisholm Trail Parkway project within the Edwards Ranch-Riverhills development. Currently drainage from the Chisholm Trail Parkway project is routed through a series of retention/detention ponds running south-to-north on either side of roadway, which is currently under construction. The retention/detention ponds were included in the Final Environmental Impact Statement FHWA-TX-EIS-90-05-F State Highway 121 from IH 30 to FM 1187 Tarrant County, Texas, dated October 2004. However, the two outfall structures were not included in this NEPA document. The two outfall structures are necessary to allow for the storm water drainage system of this section of the Chisholm Trail Parkway to drain as designed.
The piping connecting the outfall structures and the retention/detention ponds would cross the levee easement along the Clear Fork Trinity River and flow into the Fort Worth Floodway and channel, which is a federal project. At the time the Chisholm Trail project was first initiated (i.e., NEPA documentation completed), the Section 408 approval requirement did not exist. Therefore an SEA to address Section 408 is required.
Anticipated Environmental Effects. The Supplemental Environmental Assessment (SEA) considers two alternatives, including the no action. The proposed action includes the installation of two outfall structures into the Clear Fork Trinity River. These two outfalls will provide necessary drainage for the Chisholm Trail Parkway project within the Edwards Ranch/Riverhills development. The piping connecting the outfall structures and the retention/detention ponds would cross the levee easement along the Clear Fork Trinity River and flow into the Fort Worth Floodway and channel. The eastern outfall (Storm Drain E4) will consist of a 4-foot concrete apron connected to two 6-foot by 3-foot reinforced concrete boxes (RCB). The two RCB’s will connect to the eastern retention/detention pond that collects drainage from the east side of Chisholm Trail Parkway. The western outfall (Storm Drain W4) will also consist of a 4-foot concrete apron connected by two 4-foot by 4-foot RCB. The two RCB’s will connect to the western retention/detention pond that collects drainage from the west side of Chisholm Trail Parkway.
No significant adverse direct, indirect, or cumulative impacts to the human and natural environment associated with implementation of the proposed action are identified. No known cultural resources are extant within the area of potential effect. There are no anticipated impacts to habitat for threatened or endangered species, and all impacts to wetlands and waters of the U.S. would be minimal and fall within the limits of Nationwide Permit 12 – Utility Line Activities (Project No. SWF-2012-00324) in compliance with Section 404 of the Clean Water Act. The proposed action would result in impacts to both grassland and riparian woodland vegetation. The disturbance area at both outfalls is proposed to be sodded post-construction to restore the vegetation grassland community to pre-construction conditions. Approximately 25 trees would be removed to construct Storm Drain E4 and approximately 50 trees would be removed to construct Storm Drain W4. USACE does not require woodland mitigation for Section 408 actions, unless impacts occur with Section 404 jurisdictional areas. This action does not require a pre-construction notification or compensatory mitigation under Section 404.
Conclusions. Based on a review of the information contained in this SEA, it is determined that the implementation of the proposed action is not a major federal action, which would significantly affect the quality of the human environment within the meaning of Section 102(2)(c) of the National Environmental Policy Act of 1969, as amended. Therefore, the preparation of an Environmental Impact Statement is not required.
Charles H. Klinge
Colonel, US Army
Commanding
Draft Supplemental Environmental Assessment