Comment Period: November 23 – December 23, 2022
SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a proposal to establish the Cache Slough Mitigation Bank. This notice is to inform interested parties of the proposed activity and to solicit comments. A copy of the Cache Slough Mitigation Bank prospectus is available online at the following location: https://ribits.ops.usace.army.mil/ords/f?p=107:278::::rp,278:p278_bank_id:6367
AUTHORITY: This prospectus is being evaluated under 33 Code of Federal Regulations (CFR) Part 332.8.
SPONSOR: Westervelt Ecological Services, LLC
LOCATION: The approximately 350-acre property site is located immediately northeast of the City of Rio Vista (Figures 1 and 2), bounded on the north and northeast by Watson Hollow Slough, on the west by the Mellin Levee Extension, on the southwest by the Mellin Levee, and on the southeast by Solano County Levee 28; a restricted-height levee along Cache Slough, and the Sacramento River (Figure 3). State Route (SR) 84 is situated on the top of the restricted-height levee and connects the City of Rio Vista to the Ryer Island Ferry. The approximate center of the site is located at latitude 38.18194°, longitude -121.67468°, Solano County, California.
PROJECT DESCRIPTION: The prospective Sponsor proposes to establish an approximately 350-acre mitigation bank. The project would result in the re-establishment of approximately 34 acres of upland habitat and re-establishment of 316 acres of waters of the United States, including wetlands, in or adjacent to the Sherman Lake-Sacramento River 10-digit watershed. The mitigation bank proposes to offer 212 tidal, freshwater wetland credits which would include dual species credits for Delta smelt, North American green sturgeon, California Central Valley steelhead, Chinook salmon (Central Valley spring-run and Sacramento River winter-run) and giant garter snake; and 104 credits of floodplain, riparian credits which include dual species credits for California Central Valley steelhead, Chinook salmon (Central Valley spring-run and Sacramento River winter-run) and giant garter snake. The attached restoration concept (Figure 33) provides additional details.
The proposed Service Area for the Bank includes the extent of the Lower Sacramento 8-digit hydrologic unit code (HUC) sub-basin containing the Bank and the adjoining 8-digit HUC sub-basins limited to the Central Valley EPA Level III Ecoregion, with the exception of the Suisun Bay watershed. The service area maps are shown on the attached Figures 28-32.
Environmental Setting. The existing jurisdictional aquatic resources on the Bank property include the following seven aquatic habitat types: approximately 10 acres of open water, 2 acres of emergent marsh, 4 acres of seasonal wetland, 18 acres of clay flat, and 16 acres of riparian. There are approximately 60 acres of wetlands within the project area. Current habitats on the Bank property include areas of former farm fields, irrigated pasture, and managed waterfowl habitat delineated as uplands and managed marsh.
The site is currently used primarily for cattle grazing and for waterfowl habitat and hunting. It is divided into four former agricultural fields. These fields form somewhat hydrologically isolated areas, at least from shallow surface water. The fields are divided by three elevated agricultural ditches (“highline ditches”) that parallel each other and are oriented in a northeast/southwest direction. These ditches are composed of mounded dirt (displaced soil) that rise roughly 2 to 2.5 feet above existing grade and function as berms to connect the south berm of Watson Hollow Slough to the Mellin Levee and Mellin Levee Extension (Figure 3). These elevated ditches once may have supported irrigation pipe but now are earthen lined.
The Bank property does not contain any buildings. An abandoned natural gas well and associated infrastructure (i.e., gravel pad and access pad, shed, and fencing) are present in the northwest corner of the Bank property.
Culverts and associated screw/slide gates are present on Watson Hollow Slough along the northern boundary of the Bank property to allow for water management to support irrigated pasture and waterfowl habitat (Figure 3).
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 includes representatives from the Corps, US Environmental Protection Agency (USEPA), US Fish and Wildlife Service (USFWS) and National Oceanic and Atmospheric Administration (NOAA).
HISTORIC PROPERTIES: A cultural resource inventory and report is being prepared and will be available when the draft Bank Enabling Instrument (BEI) is submitted.
ENDANGERED SPECIES: The proposed 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 Bank would not adversely affect Essential Fish Habitat (EFH) as defined in the Magnuson-Stevens Fishery Conservation and Management Act. The Corps will initiate consultation with the National Marine Fisheries Service, pursuant to Magnuson-Stevens Fishery Conservation and Management Act, as appropriate.
The above determinations are based on information provided by the 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 in order to consider and evaluate the impacts of this 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-2022-00357 must be submitted via email to the office listed below on or before December 23, 2022.
Cynthia D. Ovdenk
Senior Project Manager
CA Delta Section
US Army Corps of Engineers, Sacramento District
Attachments: 8 Figures