Ancestor Creek Habitat Improvement Project EA # DOI-BLM-CA-N030-2021-0008 U.S. Department of the Interior Bureau of Land Management (BLM) Arcata Field Office Arcata, CA Prepared By: _____________________________________ ___/___/___ Zane Ruddy, Fish Biologist Reviewed By: ______________________________________ ___/___/___ Dan Wooden, Assistant Field Manager 1. Introduction Background and Setting Ancestor Creek is a one square mile tributary to the upper Mattole River in northern Mendocino County (Figure 1). The BLM manages one 40-acre parcel in the watershed, and the remainder of the watershed is managed by the California State Parks and private landowners. The watershed is primarily second growth conifer and hardwood-dominated forest. Ancestor Creek has been identified as a priority tributary for habitat restoration for Endangered Species Act threatened coho salmon (Oncorhyncus kisutch), Chinook salmon (O. tshawytscha), and steelhead (O. mykiss) in the Mattole River (MRRP 2011, NMFS 2014, NMFS 2016) and recent spawner and juvenile surveys have identified it as one of the only streams where coho salmon persist in the watershed (MRRP 2011). Landscape disturbance in the Mattole River watershed, primarily logging and road building during the 1950s – 1980s, and wood removal during the early-mid 1980s, vastly decreased salmonid rearing habitat by disconnecting floodplains from the main channel and increasing channel incision. Juveniles rely on slower velocity habitats for shelter during the winter months, deep pools for protection from predators and increasing temperatures during the summer, and off-channel habitats that support macroinvertebrates. The lack of channel complexity in Ancestor Creek has created a “bowling alley” effect (Figure 2) in which water travels through the channel at high velocity causing incision and bank undercuts therefore reducing habitat and depositing fine sediment into the system. The addition of instream wood would change the release and residence time of water in the system, consequently increasing off-channel rearing and summer refugia habitat for salmonids, slowing channel incision and providing an overall resiliency to disturbance, specifically high flow events (Beaver Restoration Guidebook Pollock et al. 2017). The reach of Ancestor Creek within the BLM-managed parcel provides an ideal setting for addressing several of these limiting factors in one of the few remaining areas utilized by coho salmon in the Mattole River watershed. Purpose and Need for Action and Decision to be Made As part of a comprehensive effort to recover threatened salmonids in the Mattole River, a need exists to improve and increase juvenile rearing habitat for these fish in the watershed. The purpose of this project is to improve aquatic habitat conditions by installing small wood structures in strategic locations to influence physical processes in ways that improve fish habitat. The decision to be made is whether or not to restore habitat in Ancestor Creek to benefit native fish populations in the Mattole River. Conformance with Land Use Plan This proposed action is subject to conformance with the Arcata Planning Area Resource Management Plan Amendment and Environmental Assessment Decision Record (1996), and the Northwest Forest Plan (USDA and USDI 1994), as amended. These plans have been reviewed to determine if the proposed action conforms with applicable land use plan terms and conditions as required by 43 CFR 1610.5 Management actions would comply with the Northwest Forest Plan Aquatic Conservation Strategy. The Mattole River watershed is designated as a Tier 1 Key Watershed. Since most of the project area lies within Riparian Reserves, standards and guidelines for Riparian Reserves prohibit or regulate activities that retard or prevent attainment of the Aquatic Conservation Strategy objectives (USDA and USDI 1994). 1 Figure 1. Map of the project area. All activities would occur in Ancestor Creek (dashed blue line) on the 40-acre BLM parcel (shaded yellow). 2 Figure 2. Reach of Ancestor Creek exhibiting the low habitat value “bowling alley” channel form typical throughout the proposed project area. Discharge represented is winter baseflow. Relationship to Statutes, Regulations or Other Plans The proposed action requires consultation under the federal Endangered Species Act because three listed fish species are present in the vicinity of the project area. The proposed action would require permitting under Sections 401 and 404 of the Clean Water Act. The proposed action is consistent with the 2001 Record of Decision and Standards and Guidelines for Amendments to the Survey and Manage, Protection Buffer, and other Mitigation Measures Standards and Guidelines (USDA and USDI 2001), as modified by the 2011 Settlement Agreement. The Project meets Northwest Ecosystem Alliance v. Rey, Case No.04-844 (W.D. Wash. Oct.10, 2006) Pechman Exemption c: “Riparian and stream improvement projects where the riparian work is riparian planting, obtaining material for placing in-stream, and road or trail decommissioning; and where the stream improvement work is the placement large wood, channel and floodplain reconstruction, or removal of channel diversions” as well as the 2011 Settlement Agreement Conservation Northwest v. Sherman Case No. 08-CV-1067-JCC (W.D. Wash.) fish and wildlife project exemption, Section IV.A.2.c. “Snag and down log creation when treatments retain 60% canopy cover. On any given acre, not more than 20% of any stand dominant or co-dominant cohort may be used to create snags and down wood”. The BLM is required to evaluate wilderness character of all areas subject to project- related activities. The project is in a non-contiguous 40-acre tract of public land. Due to its small size, the area does not contain wilderness characteristics. It has not been 3 demonstrated that this area is of sufficient size as to make practicable its preservation and use in an unimpaired condition. Scoping and Issues The project was scoped with BLM specialists on March 16, 2021. Aquatic species and essential fish habitat, riparian, water quality, floodplains, and wildlife were identified as resources that would need to be included in the environmental assessment. 2. Proposed Action and Alternatives Proposed Action The proposed project would place up to 20 small instream wood structures and up to 20 trees (up to 20 inches diameter at breast height (DBH)) over a 2,000-foot section of Ancestor Creek (Figure 3) over a five-year period (2021-2025). Project implementation would occur between June 15th and November 1st of each year. Structure maintenance (e.g., adding weaving material) would occur as needed throughout the year and would be limited to handwork. Design of the structures is informed by the Beaver Restoration Guidebook (Pollock et al. 2017) and restoration projects on Baker Creek and Lost River in the Mattole River headwaters. The project would follow measures outlined in the NOAA Restoration Center/Army Corps’ programmatic Biological Opinion (NFMS 2012) to minimize potential effects to listed fish species. The 20 proposed wood structures would consist of a series of small-diameter (<6-inches DBH) untreated conifer posts sourced from a nearby forest fuels reduction project or lumber supplier, and weaving material (e.g., redwood and huckleberry branches) sourced near the project area. Posts would either be driven into the channel using a gas-powered pounder or manually with a post pounder or sledge hammer. Each structure would be approximately one to two feet deep. Once installed, channel-spanning structures would not exceed one foot above the existing streambed, and all other structures would be partial-spanning and would not exceed two feet in height. The maximum width of structures would be 15 feet. The structures would be semi-permeable, allowing for fish passage, and are designed to direct water to a naturally occurring side channels during high flow events. Example illustrations of the proposed structures can be seen in Appendix A. Up to 20 understory trees would be felled into the channel to increase habitat complexity and disperse stream energy. Trees would have a maximum DBH of 20 inches and would be selected to maintain instream shade and ensure streambank integrity. Trees would be dropped using a gas-powered chainsaw or a hand saw. After being felled, trees may be shifted into more suitable locations within the channel using a winch or grip hoist. Trees that exhibit high vigor, a good crown ratio and dominance in the stand would not be removed. Trees that may be of high wildlife value would also be retained. Wildlife trees include trees with broken or damaged tops, cavities, or other unusual growth that may be used by northern spotted owls, marbled murrelets, or other cavity utilizing animals. Tree stumps would be cut or re-cut as low to the ground as possible. 4 Figure 3. Example locations of wood structures (red lines) and trees felled into channel (tree icon). Actual locations will be dictated by on-the-ground conditions each year. Fish are not anticipated in the proposed work areas due to the shallow (or completely dry) and exposed nature of the existing habitat during the low flow work season. As an added protective measure, all proposed work areas would be surveyed by a biologist prior to project implementation and any areas with fish present would be avoided. Therefore, fish would not need to be relocated or excluded from work areas. Sediment fencing would be placed immediately downstream of work areas to prevent