2013-19813. Intent To Prepare a Draft Environmental Impact Statement for Dam Safety Study, Lake Lewisville Dam, Elm Fork Trinity River, Denton County, Texas

AGENCY:

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

ACTION:

Notice of intent.

SUMMARY:

Authorized by the River and Harbor Act of March 2, 1945, Lake Lewisville embankment construction began in December 1948 with completion in August 1955. The project includes an earthen embankment that is approximately 32,000 feet in length and has a maximum height of 125 feet at elevation 560 feet (all elevations are NGVD) with gated outlet works and an uncontrolled concrete ogee weir spillway. The primary purposes of the project are flood risk management, water supply, recreation and non-Federal hydropower. Top of conservation pool was originally set at elevation 515.

Following construction of Ray Roberts Dam upstream, the conservation pool of Lewisville was raised from elevation 515 to 522 on November 30, 1988. At elevation 522, the lake inundates approximately 29,600 surface acres. Top of flood pool is elevation 532 which inundates approximately 39,200 surface acres. Downstream of the dam, approximately 2,000 acres of Corps of Engineers (Corps) owned lands are currently leased by the Lewisville Lake Environmental Learning Area. A former fish hatchery is also operated by the government for national research on controlling nuisance aquatic plants.

The risk associated with the Lake Lewisville project was first evaluated in 2005 after the Corps instituted a Screening Portfolio Risk Assessment (SPRA) program to assess the risk of all 694 dams in the Corps' portfolio. The SPRA report completed in July 2005, was reviewed by Corps senior dam safety officials who concluded that the risks associated with the possible poor performance of the dam were above the Corps' tolerable risk guidelines. As a result, additional studies of the project were initiated. These studies are currently ongoing, and will evaluate appropriate ways to minimize risk associated with the project. While the Corps completes in-depth studies of the project to determine appropriate permanent methods for correcting potential problems, interim risk reduction measures have been implemented. In anticipation of possible permanent corrective actions at the project, and in order to fully comply with National Environmental Policy Act (NEPA) requirements, the Corps is preparing a project report and a Draft Environmental Impact Statement (DEIS) to identify the environmental impacts associated with any alternatives to repair and reduce risks at the Lake Lewisville Dam. The general study area will be the Lake Lewisville proper and floodplain from Ray Roberts Dam downstream to Interstate Highway 20 in Dallas County.

DATES:

A public scoping meeting will be held on August 20, 2013 beginning at 7:00 p.m.

ADDRESSES:

The meeting will be held at the Medical Center of Lewisville—Grand Theater Black Box Theater Room, 100 North Charles Street, Lewisville, TX 75057.

FOR FURTHER INFORMATION CONTACT:

Questions pertaining to the proposed action and DEIS can be addressed to: Ms. Hollie Hunter, Environmental Project Manager, CESWF-PER-EE, U.S. Army Corps of Engineers, Fort Worth District, P.O. Box 17300, Fort Worth, TX 76102-0300, [phone].

SUPPLEMENTARY INFORMATION:

The study area lies within an area of rapid growth in the Lewisville, Grapevine, Dallas, Texas corridor along the Elm Fork and Mainstem floodways of the Trinity River.

Alternatives will be developed and evaluated based on ongoing research and data collection and past studies conducted by the Corps. Preliminary alternatives considered will include dam modifications necessary to reduce risk to acceptable levels, and will include consideration of any required hydraulic, environmental or recreational mitigation.

The public will be invited to participate in the scoping process, invited to attend public meetings, and given the opportunity to review the DEIS. The first public scoping meeting will be on (see DATES and ADDRESSES). Subsequent public meetings, if deemed necessary, will be announced in the local news media. Release of the DEIS for public comment is scheduled for September 2014. The exact release date, once established, will be announced through mailings to known interested individuals, agencies and officials and in the local news media.

Future coordination with other agencies and public scoping will be conducted to ensure full and open participation and aid in the development of the DEIS. All affected Federal, state, and local agencies, affected Indian tribes, and other interested private organizations and parties are hereby invited to participate. Continued coordination will also be conducted with the U. S. Fish and Wildlife Service (USFWS). The USFWS will furnish information on threatened and endangered species in accordance with the Endangered Species Act. In addition, the USFWS will also be requested to provide support with planning aid and to provide a Fish and Wildlife Coordination Act Report. The State Historic Preservation Office will be consulted as required by Section 106 of the National Historic Preservation Act.

Dated: August 7, 2013.

Eric W. Verwers,

Chief, Planning, Environmental, and Regulatory Division.