2017-09146. Supplemental Final Environmental Impact Statement for the Dam Safety Modification Report, Bluestone Dam, Hinton, Summers County, WV

AGENCY:

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

ACTION:

Supplemental Final Environmental Impact Statement—Public and agency comment period.

SUMMARY:

Pursuant to the National Environmental Policy Act (NEPA), the U.S. Army Corps of Engineers (Corps), Huntington District has prepared a Supplemental Final Environmental Impact Statement (SFEIS) to disclose potential impacts to the natural, physical, and human environment resulting from modifications to Bluestone Dam. The original EIS was published in 1998 and a Record of Decision (ROD) was signed in 1999 concluding the NEPA process allowing the Corps to initiate implementation of the Bluestone Dam Safety Assurance (DSA) Project. When completed, the current modifications under construction will strengthen the dam's stability and allow for increased discharge capacity through the use of hydropower penstocks substantially reducing risk. However, physical modeling and expert analysis conducted during project construction indicated the downstream bedrock is vulnerable to an unacceptable degree of erosion during high flow events. The Corps has also recognized potential for unacceptable erosion associated with overtopping of areas of the dam not designed to be overtopped. After a full consideration of alternatives to achieve acceptable risk levels, this SFEIS recommends implementing modifications to the existing stilling basin to prevent scour that could result in spillway instability and thus dam failure. Proposed modifications include alteration to the existing stilling basin to include installation of a protective concrete apron and larger baffles among other features described in the SFEIS. This SFEIS also addresses the impacts associated with prolonged construction duration of modification features described in the original EIS and ROD.

DATES:

The review period will be open from May 1, 2017 to May 30, 2017.

ADDRESSES:

Send written comments concerning this proposed project to Rebecca Rutherford, Chief, Environmental Analysis Section, Planning Branch, U.S. Army Corps of Engineers, Huntington District, 502 Eighth Street, Huntington, WV 25701-2070. Telephone: [phone]. Electronic mail: [e-mail]. Requests to be placed on the mailing list should also be sent to this address.

SUPPLEMENTARY INFORMATION:

1. Authority: Bluestone Dam and Reservoir was authorized by Executive Order (EO) 7183 in 1935 and the Flood Control Acts of 1936 and 1938 for the purposes of flood control, low flow augmentation, and hydroelectric power development. The purposes were later expanded to include recreational activities under the Flood Control Act of 1944 and fish and wildlife enhancement under the Fish and Wildlife Coordination Act (FWCA) of 1958.

2. Background: a. Guidance for this study is provided in USACE Engineer Regulation (ER) 1110-2-1156 (October 2011). This guidance details agency policy and procedures for the study and implementation process addressing dam safety issues.

b. Bluestone Lake is a multipurpose component of the Kanawha River basin system which provides for flood control, recreation, hydropower development, low flow augmentation, and fish and wildlife enhancement. The project began operation in 1949 and helps control a 4,600 square mile drainage area.

c. The ROD, signed in 1999, completed the NEPA process for the DSA project permitting the Huntington District to begin detailed design and subsequent construction of the recommended alternative which included a 13 foot cantilever wall on top of the dam, an additional concrete monolith on the east abutment, a floodgate closure across WV Rt. 20, removable closures at each end of the spillway, high strength anchors placed into the dam itself, massive concrete blocks placed against the downstream face of the dam, and a pavement for scour protection downstream of the hydropower penstocks. The majority of the ongoing construction on these measures will continue through the year 2019. The ROD for this work anticipated construction would be completed 2005.

d. Physical modeling and expert analysis conducted during project construction has shown the downstream bedrock is vulnerable to erosion during high flow events as a result of deficiencies with the current stilling basin configuration. This potential erosion creates an unacceptable level of risk according to guidelines established in ER 1110-2-1156, under which this study is being conducted.

e. The SFEIS and Dam Safety Modification report (DSMR) have considered the structural integrity of the dam, its ability to accommodate flood waters as well as transportation, noise, terrestrial, aquatic, economic, environmental justice and cultural resource issues associated with the performance of the dam. The SFEIS and DSMR has recommended any modifications necessary to ensure the long-term safe performance of the structure as originally intended.

f. Modifications to meet current acceptable risk guidelines per ER 1110-2-1156 proposed include, alteration to the existing stilling basin to include installation of a protective concrete apron and larger baffles among other features described in the SFEIS. The No Action alternative will also be considered. As required by NEPA and Corps planning guidance, the No Action alternative will form a benchmark from which alternatives are evaluated and compared.

3. Public Participation: a. The SFEIS will be made available to the public for thirty (30) days for review and comment. A Notice of Availability will be advertised in affected area newspapers informing the general public about the SFEIS public review period. The SFEIS and draft final ROD can be viewed at: http://www.lrh.usace.army.mil/​Missions/​PublicReview.aspx. Copies of the SFEIS and draft final ROD may be obtained by contacting the Huntington District Office of the U.S. Army Corps of Engineers at [phone] (See ADDRESSES). All persons and organizations that have an interest in the Bluestone Dam Project are urged to participate in this SFEIS review and comment period. Upon the close of the comment period, USACE will consider all comments.

4. Schedule: The Supplemental Final Environmental Impact Statement is scheduled to be released for public review and comment on or about May 1, 2017.

Rebecca A. Rutherford,

Chief, Environmental Analysis Section, Planning Branch.