Comments Period: April 9, 2021 – May 9, 2021
SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a proposal to establish Walker River Mitigation Bank, which would result in the establishment, enhancement, and preservation of approximately 65.4 acres of waters of the United States, including wetlands, in or adjacent to the West Walker River watershed (Hydrologic Unit Code: 16050302). This notice is to inform interested parties of the proposed activity and to solicit comments. A copy of the Walker River Mitigation Bank, Mitigation Bank Prospectus and supporting documents is available online at the following location: https://ribits.ops.usace.army.mil/ords/f?p=107:278:11514014155665::NO::P278_BANK_ID:5564.
AUTHORITY: This prospectus is being evaluated under 33 Code of Federal Regulations (CFR) Part 332.8.
SPONSOR: Natural Resources Group, Inc. (Attention: Skip Moss)
LOCATION: The approximately 89.6-acre site is located on the West Walker River, approximately 3.2 miles north of Coleville and east of State Route 395, Latitude 38.604272°, Longitude -119.517347°, in Mono County, California, and can be seen on the Coleville 24K USGS Topographic Quadrangle.
PROJECT DESCRIPTION: The prospective sponsor proposes to establish an approximately 89.6-acre mitigation bank. As proposed, the bank would provide riparian wetland and wet meadow establishment credits; wet meadow, OHWM floodplain, and upland watershed enhancement credits; and West Walker River preservation credits. The proposed service area is shown on figure 7 of the attached drawings and on figure 15 of the prospectus. Development of the proposed bank would be accomplished by removing the current grazing pressure, planting native and naturalized vegetation, and allowing for the natural recovery and recruitment of riparian and wetland species. Onsite cuttings would be used to accelerate riparian vegetation colonization in certain areas, but natural recruitment from the existing seed bank and seed inputs from upstream sources are expected to facilitate the rapid establishment of a diverse riparian corridor. Establishment of wetlands would be accomplished by reducing the elevation of upland areas until they are at an elevation where wetland hydrology will naturally occur. The construction would be cut-and fill neutral, in that no material would be imported to or removed from the site. Riparian areas would be planted with desirable tree species post construction, and wet meadow areas would be allowed to vegetate naturally, unless suitable plantings are sourced for revegetation. Post establishment, an ecologically-minded grazing management program (likely including short, concentrated periods of grazing, called “flash grazing”) would be implemented to provide thatch control and improve species composition. The proponent anticipates that these restoration activities would rapidly improve water quality (dissolved oxygen, nitrogen load, temperature, turbidity, etc.) and riparian habitat quality, and would allow the bank site to recover the ecological functions and values of this stretch of the West Walker River. Restoration is also expected to provide floodplain connectivity, improve ecological health through floodplain and in channel habitat recovery, and improve nutrient attenuation capacity of the river/riparian system. The attached drawings provide additional details.
Environmental Setting. There are approximately 44.06 acres of aquatic resources within the proposed bank site, including 10.96 acres of wetlands and 33.1 acres of perennial and intermittent streams. The site is in the west central area of Antelope Valley just north of Coleville and south of Topaz Lake. Antelope Valley is bordered on the west by the eastern Sierra foothills and on the east by the Sweetwater mountain range. Antelope Valley has historically been a mixture of grassland, sagebrush, and bitterbrush scrub and wetlands, but has undergone extensive agricultural development. Much of Antelope Valley is now dedicated to row crops, hay and grain production, and livestock grazing. Many properties in the region, including the proposed bank site are severely degraded from intensive, persistent, and detrimental grazing practices. Riparian vegetation along the West Walker River within the project site is nearly non-existent. The channel is over-wide and shallow because there is no vegetation left to hold the banks together. Annual recruitment of new plants is near zero due to the ongoing grazing practices. The project site is relatively flat with a gentle slope from south to north, generally towards the West Walker River, and following the flow of the West Walker River. Elevations onsite range from approximately 5,047 feet above mean sea level in the south to 5,030 feet above mean sea level near the north, where the West Walker River flows offsite. The site contains six soil types: Brockliss gravelly loamy coarse sand, Gurdugee clay loam, Gurdugee loamy coarse sand, Jubilee peat, Mottsville loamy coarse sand, and Riverwash-Water complex .
A Department of the Army permit may be required for restoration activities.
OTHER GOVERNMENTAL AUTHORIZATIONS: The Interagency Review Team responsible for the review and approval of the proposed mitigation bank include representatives from the Corps, United States Environmental Protection Agency, California Regional Water Quality Control Board, and the California Department of Fish and Wildlife.
HISTORIC PROPERTIES: Potentially eligible cultural resources may be affected by the proposed mitigation bank. The Corps will initiate consultation with the State Historic Preservation Officer under Section 106 of the National Historic Preservation Act, as appropriate.
ENDANGERED SPECIES: The proposed mitigation bank 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 and/or the National Marine Fisheries Service, pursuant to Section 7 of the Endangered Species Act, as appropriate.
ESSENTIAL FISH HABITAT: The proposed mitigation bank will 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 prospective Sponsor and our preliminary review.
EVALUATION FACTORS: The Corps is soliciting comments from the public, Federal, State, and local agencies and officials, Indian tribes, and other interested parties to consider and evaluate the impacts of this proposed bank. Any comments received will be considered by the Corps to assess impacts on endangered species, historic properties, water quality, general environmental effects, and other public interest factors. Comments are used in the evaluation of the proposed bank per 33 CFR Part 332.8 and in the preparation of an Environmental Assessment pursuant to the National Environmental Policy Act.
SUBMITTING COMMENTS: Written comments, referencing Public Notice SPK-2019-00112 must be submitted to the office listed below on or before May 9, 2021.
William Ness, William Ness
Senior Project Manager
California South Section
US Army Corps of Engineers, Sacramento District
1325 J Street, Room 1350
Sacramento, California 95814-2922
Telephone: (916) 557-5268
Attachments: 7 drawings