Intent to Prepare a Draft Environmental Impact Statement for the Success Dam Seismic Remediation Project, CA

AGENCY:

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

ACTION:

Notice of intent.

SUMMARY:

Pursuant to the National Environmental Policy Act of 1969, as amended, the U.S. Army Corps of Engineers, Sacramento District (Corps), intends to prepare a Draft Environmental Impact Statement (EIS) for the Federal action to remediate seismic dam safety concerns at the Lake Success Project located on the Tule River, near Porterville, CA. The proposed action is being conducted through the Corps' Dam Safety Assurance Program for the evaluation of existing dams.

ADDRESSES:

Submit questions or comments regarding the subject dam safety project to Mr. Matt Davis, U.S. Army Corps of Engineers, 1325 J. Street, Sacramento, CA 95814-2922, fax (916) 557-7856, or e-mail: Matthew.G.Davis@usace.army.mil. Requests to be placed on a mailing list for this project should also be sent to this address.

FOR FURTHER INFORMATION CONTACT:

Mr. Matt Davis, (916) 557-6708.

SUPPLEMENTARY INFORMATION:

1. Background Information. Based on current engineering knowledge, the Corps has determined that Success Dam near Porterville, CA, in Tulare County, has a fairly high likelihood of failure in the event of an earthquake. All studies that have been conducted show that the dam is likely to fail under relatively low levels of earthquake shaking. The estimated probability of a damaging earthquake that would breach or overtop the dam in its current condition is 1 in 285. Historical records indicate that at least three times between 1857 and 1952, earthquakes shook the future Success Dam site sufficiently that the current dam would have been seriously damaged with a likely release of the reservoir had the dam been present. However, no such earthquakes have occurred in the 44 years since the dam was built. Given the potential for seismicity at and near the Success Dam, along with the characteristics of the materials comprising the dam and its foundation, remediation work is required to prevent loss of life, extensive downstream damage, functional loss of the project, and loss of all project benefits. The project is currently being operated at a reduced capacity to deal with the risk until a permanent solution is implemented to address the dam safety concern.

2. Proposed Action and Alternatives. The Corps' tentatively preferred alternative is to construct a new roller compacted concrete (RCC) dam immediately downstream of the existing earthen dam. In addition to the no-action alternative, other alternatives to be evaluated include a new earthen embarkment dam immediately downstream of the existing dam, and modifications to the existing dam consisting of upstream jet grout with removal and replacement of the downstream foundation. The proposed RCC dam alternative would not provide any additional storage capacity beyond the existing dam. However, additional storage for flood protection and irrigation water would be provided under the separately authorized dam spillway raise project. Construction of the spillway raise project may be integrated into the construction of the dam safety project. The exact nature and extent of alternatives will be determined based on public and agency input during the scoping period and preparation of the Draft EIS.

3. Issues to be Addressed. The Draft EIS will address environmental issues concerning the proposed action. Issues will be identified based on public input during the scoping period and during preparation of the Draft EIS. Issues identified initially as potentially significant include: hydrology, biological resources, recreation, land use, visual quality, traffic safety, cultural resources, noise, and air quality.

4. Public Involvement. The Corps will hold a public scoping meeting to receive public comments and to solicit input regarding environmental issues of concern to the public and the alternatives that should be addressed in the Draft EIS. The public scoping meeting place, data and time will be advertised in the Draft EIS. The public scoping meeting place, date and time will be advertised in advance in local newspapers, and meeting announcement letters will be sent to interested parties. Written comments may also be submitted via mail and should be directed to Mr. Matt Davis (see ADDRESSES).

5. Cooperating Agencies. Federal agencies interested in participating as a Cooperating Agency are requested to submit a letter of intent to Colonel Ronald N. Light, District Engineer (see ADDRESSES).

6. Availability of Draft EIS. The Corps intends to issue the Draft EIS in the spring of 2006. The Corps will announce availability of the draft in the Federal Register and other media, and will provide the public, organizations, and agencies with an opportunity to submit comments, which will be addressed in the Final EIS.