Floodplain/wetland assessment of the effects of construction and operation ofa depleted uranium hexafluoride conversion facility at the Paducah, Kentucky,site.

The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF{sub 6} inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This floodplain/wetland assessment has been prepared by DOE, pursuant to Executive Order 11988 (''Floodplain Management''), Executive Order 11990 (Protection of Wetlands), and DOE regulations for implementing these Executive Orders as set forth in Title 10, Part 1022, of the ''Code of Federal Regulations'' (10 CFR Part 1022 [''Compliance with Floodplain and Wetland Environmental Review Requirements'']), to evaluate potential impacts to floodplains and wetlands from the construction and operation of a conversion facility at the DOE Paducah site. Reconstruction of the bridge crossing Bayou Creek would occur within the Bayou Creek 100-year floodplain. Replacement of bridge components, including the bridge supports, however, would not be expected to result in measurable long-term changes to the floodplain. Approximately 0.16 acre (0.064 ha) of palustrine emergent wetlands would likely be eliminated by direct placement of fill material within Location A. Some wetlands that are not filled may be indirectly affected by an altered hydrologic regime, due to the proximity of construction, possibly resulting in a decreased frequency or duration of inundation or soil saturation and potential loss of hydrology necessary to sustain wetland conditions. Indirect impacts could be minimized by maintaining a buffer near adjacent wetlands. Wetlands would likely be impacted by construction at Location B; however, placement of a facility in the northern portion of this location would minimize wetland impacts. Construction at Location C could potentially result in impacts to wetlands, however placement of a facility in the southeastern portion of this location may best avoid direct impacts to wetlands. The hydrologic characteristics of nearby wetlands could be indirectly affected by adjacent construction. Executive Order 11990, ''Protection of Wetlands'', requires federal agencies to minimize the destruction, loss, or degradation of wetlands, and to preserve and enhance the natural and beneficial uses of wetlands. DOE regulations for implementing Executive Order 11990 as well as Executive Order 11988, ''Floodplain Management'', are set forth in 10 CFR Part 1022. Mitigation for unavoidable impacts may be developed in coordination with the appropriate regulatory agencies. Unavoidable impacts to wetlands that are within the jurisdiction of the USACE may require a CWA Section 404 Permit, which would trigger the requirement for a CWA Section 401 Water Quality Certification from the Commonwealth of Kentucky. A mitigation plan may be required prior to the initiation of construction. Cumulative impacts to floodplains and wetlands are anticipated to be negligible to minor under the proposed action, in conjunction with the effects of existing conditions and other activities. Habitat disturbance would involve settings commonly found in this part of Kentucky, which in many cases involve previously disturbed habitats