Comments Period: July 24 – August 8, 2015
SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a permit application to construct the Ralston Afterbay Sediment Management project, which would result in impacts to approximately 27 acres of waters of the United States. This notice is to inform interested parties of the proposed activity and to solicit comments.
AUTHORITY: This application is being evaluated under Section 404 of the Clean Water Act for the discharge of dredged or fill material in waters of the United States.
APPLICANT: Placer County Water Agency, Attn: Mr. Ben Ransom, 144 Ferguson Road, Auburn, California 95603
LOCATION: The 37.47-acre site is located on Ralston Afterbay Reservoir, Middle Fork American River, in Tahoe and Eldorado National Forests, Sections 2, 3, and 4 of Township 13 North, Range 11 East, and Section 33 of Township 14 North, Range 11 East, Mount Diablo Baseline & Meridian, Latitude 39.00323°, Longitude -120.74648°, Placer and El Dorado Counties, California, and can be seen on the CA-MICHIGAN BLUFF USGS Topographic Quadrangle.
PROJECT DESCRIPTION: Placer County Water Agency (PCWA) operates the Middle Fork Project (MFP), a multi-purpose water supply and hydro-generation project. The MFP has been operated under an annual 50-year Federal Energy Regulatory Commission (FERC) license since the expiration of the original 50-year license in 2013. PCWA is currently awaiting renewal of the long term FERC license. During the annual FERC relicensing process, PCWA collaborated extensively with state and federal resource agencies, Native American tribes, non-governmental organizations, and members of the public to develop new license conditions. One of the new license conditions is the Sediment Management Plan (SMP), which describes sediment management activities necessary for continued operation of the MFP, including operations at Ralston Afterbay Reservoir (Afterbay). The currently proposed Ralston Afterbay Sediment Management project would be implemented consistent with the agency-approved SMP.
PCWA has proposed to excavate up to 100,000 cubic yards of fine and coarse sediments (about 23.7 acres) from the Afterbay. About 87,000 cubic yards of the excavated material would be sorted by size, and would be placed immediately downstream of the Ralston Dam, on Indian Bar and Junction Bar, filling an area of approximately 3.23 acres. Any excess excavated material would be transported to an alternative disposal site within the Eldorado National Forest, known as the Ralston Ridge Sediment Disposal Area. Additionally, the PCWA proposes to initiate sediment-pass-through (SPT) operations at Ralston Dam, allowing finer sediments to pass through the dam's low-level outlet gate during high flow events. SPT operations would be conducted whenever river flows exceed 3,500 cubic feet per second. PCWA has not indicated what volume of material might be released during SPT operations. PCWA has SPT monitoring protocols in place as part of their March 5, 2014 Streambed Alteration Agreement with the California Department of Fish and Wildlife.
A successful pilot project at the Afterbay was authorized by the Corps in 2002; the project as analyzed included sediment excavation, augmentation, disposal, and sediment-pass-through operations of a nature similar to the currently proposed project. Approximately 2 acres of excavated sediment was authorized to be placed within the Middle Fork American River channel at Indian Bar. Based on the results of the pilot project, PCWA has proposed that excavated material be additionally placed at Junction Bar, located approximately 500 feet downstream from Indian Bar. Based on the available information, the overall project purpose is to remove sediment and assorted debris from the Afterbay in order to increase water storage capacity, provide for more efficient operation of the power generating system, and to better regulate flows and natural migration of sediments in the Middle Fork American River downstream of Ralston Dam. The applicant has stated that there is a need for the project, because erosion and sedimentation exacerbated by the 2014 King Fire could threaten operations of the MFP at Ralston Afterbay Reservoir. The attached drawings provide additional project details.
Environmental Setting. There is approximately 27 acres of open water and perennial stream channel within the project area. The site is best characterized as a dam and reservoir on the Middle Fork American River, fed by multiple tributaries, situated in a relatively steep, canyon-bound mixed-conifer forest at an elevation of about 1150 feet above sea level.
Alternatives. The applicant has not provided information concerning project alternatives. Additional information concerning project alternatives may be available from the applicant or their agent. Other alternatives may develop during the review process for this permit application. All reasonable project alternatives, in particular those which may be less damaging to the aquatic environment, will be considered.
Mitigation. The Corps requires that applicants consider and use all reasonable and practical measures to avoid and minimize impacts to aquatic resources. If the applicant is unable to avoid or minimize all impacts, the Corps may require compensatory mitigation. The applicant has not proposed any compensatory mitigation for this project.
OTHER GOVERNMENTAL AUTHORIZATIONS: Water quality certification or a waiver from the California Regional Water Quality Control Board, as required under Section 401 of the Clean Water Act, is required for this project. The applicant has indicated they have applied for certification.
HISTORIC PROPERTIES: Based on the available information (including applicant's report titled Final National Register of Historic Places Eligibility Report for Site-05-03-53-372 and Site 05-17-54-478), one cultural resource has been identified within the area of potential effect that has the potential to be affected by the project, but this resource has been determined by the State Historic Preservation Office to be ineligible for listing in the National Register of Historic Places.
ENDANGERED SPECIES: The proposed activity may affect Federally-listed endangered or threatened species or their critical habitat. The Corps will initiate consultation with the U.S. Fish and Wildlife Service, pursuant to Section 7 of the Endangered Species Act, as appropriate.
ESSENTIAL FISH HABITAT: The proposed project would not adversely affect Essential Fish Habitat (EFH) as defined in the Magnuson-Stevens Fishery Conservation and Management Act.
The above determinations are based on information provided by the applicant and our preliminary review.
EVALUATION FACTORS: The decision whether to issue a permit will be based on an evaluation of the probable impacts, including cumulative impacts, of the described activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefit, which reasonably may be expected to accrue from the described activity, must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the described activity will be considered, including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood hazards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, consideration of property ownership and, in general, the needs and welfare of the people. The activity's impact on the public interest will include application of the Section 404(b)(1) guidelines promulgated by the Administrator, Environmental Protection Agency (40 CFR Part 230).
The Corps is soliciting comments from the public, Federal, State, and local agencies and officials, Indian tribes, and other interested parties in order to consider and evaluate the impacts of this proposed activity. Any comments received will be considered by the Corps to determine whether to issue, modify, condition, or deny a permit for this proposal. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects, and other public interest factors listed above. Comments are used in the preparation of an Environmental Assessment and/or an Environmental Impact Statement pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the proposed activity.
SUBMITTING COMMENTS: Written comments, referencing Public Notice SPK-2014-01167 must be submitted to the office listed below on or before August 8, 2015.
Zachary Fancher, Project Manager
US Army Corps of Engineers, Sacramento District
1325 J Street, Suite 1350
Sacramento, California 95814-2922
The Corps is particularly interested in receiving comments related to the proposal's probable impacts on the affected aquatic environment and the secondary and cumulative effects. Anyone may request, in writing, that a public hearing be held to consider this application. Requests shall specifically state, with particularity, the reason(s) for holding a public hearing. If the Corps determines that the information received in response to this notice is inadequate for thorough evaluation, a public hearing may be warranted. If a public hearing is warranted, interested parties will be notified of the time, date, and location. Please note that all comment letters received are subject to release to the public through the Freedom of Information Act. If you have questions or need additional information please contact the applicant or the Corps' project manager Zachary Fancher, 916-557-6643, Zachary.J.Fancher@usace.army.mil.
1) Figure 1 - Middle Fork American River Project and Vicinity
2) Figure 2 - Land Ownership in the Vicinity of Ralston Afterbay
3) Figure 3 - Ralston Afterbay Sediment Management Area Overview
4) Figure 4 - Ralston Afterbay Sediment Removal Project Proposed Work Area
5) Plan View – Impacts Within Waters of the U.S.
6) Cross Section View – Impacts Within Ralston Afterbay
7) Cross Section View – Impacts Within the Middle Fork American River Below Ralston Afterbay