Peregrine Slides Repair Project (EA 01-0B500/EFIS 0112000133) Revegetation Plan, September 2015 Applicant and Contacts This revegetation plan has been prepared to satisfy requirements of the California Department of Fish and Wildlife (CDFW) 1602 Streambed Alteration Agreement for impacts to riparian vegetation along ephemeral drainages, U.S. Army Corp of Engineers (USACE) Nationwide Permit conditions, and North Coast Regional Water Quality Control Board (NCRWQCB) Section 401 Certification conditions. The California Department of Transportation (Caltrans) is the applicant, as the party having financial responsibility for the attainment of success criteria of the proposed revegetation plan; the current and long-term owner of the proposed revegetation site; and is the party responsible for long-term maintenance of the project and revegetation site. The Caltrans Project Manager for the proposed project is Steven Blair, 1656 Union Street, Eureka CA 95501, (707) 441-5733. The designated contact persons for this revegetation plan is Caltrans Biologist Allison Kunz, 703 B Street, Marysville CA 95901, (530) 741-4103 and Caltrans Revegetation Specialist Christina Wagner, 1656 Union Street, Eureka CA 95501, (707) 441-5898. This revegetation plan was prepared by Biologist Allison Kunz, (530) 741-4103, and Revegetation Specialist, Christina Wagner, (707) 441-5898. The goal of this revegetation effort is to restore and revegetate jurisdictional areas affected by construction activities and to replace a 1,000-square foot area of riparian habitat (currently a mixed willow thicket) that will be removed due to construction at a 3:1 ratio. The plan outlines strategies for revegetation, including commitments for success criteria, monitoring, remedial measures and reporting. Location and Description of Proposed Activity The project is located on State Route (SR) 101, approximately 5 miles south of Hopland in Mendocino County, California, at post mile (PM) 3.75 – 5.3. Caltrans proposes to slow down or stop the slope movement of two (2) slide locations in Mendocino County near Hopland from 0.6 miles north of Commisky Station Road to 0.6 miles south of Pieta Creek Bridge (#10-083). Both slides are on the east side of SR 101. Formoli Slide is at PM 3.75 and Peregrine Slide is at PM 5.3. The project can be found on the Hopland U.S.G.S. 7.5-minute quadrangle, Township 12N, Range 11W, and Sections 2, 11, 14, and 23. The project is located along SR 101, adjacent to the Russian River. A gently undulating topography characterizes this stretch of SR 101. Elevation ranges from approximately 470 to 430 feet between PM 3.7 and PM 5.3 with a maximum drop in elevation of roughly 86 feet at PM 5.3 within the project environmental study limits (ESL). The natural community types, hereafter referred to as vegetation communities, reflect the dominant species within the project ESL and are classified based on plant community names (i.e., alliances and associations) provided in A Manual of California Vegetation, 2nd edition (“MCV,” Sawyer, Keeler-Wolf, and Evens 2009; the California expression of the National Vegetation Classification 1998). Alliance names were created, based on dominant species, for communities that are currently not recognized in published literature. The vegetation communities present at the project locations are comprised of Quercus lobata-Salix laevigata/Salix exigua woodland association, Avena barbata-Avena fatua grassland, and 2 Peregrine Slides Repair Project (EA 01-0B500/EFIS 0112000133) Revegetation Plan, September 2015 Nassella pulchra herbaceous alliance. No sensitive plant species nor special status plant species were observed within the ESL (see Appendix 1). Project Impacts A total of ten (10) trees will be removed for the construction of this project. From the Peregrine Slide location, 1 Quercus lobata (valley oak), 5 Salix laevigata (red willow), and 3 Salix exigua (narrowleaf willow) will be removed. One Quercus agrifolia (coast live oak) will be removed from the Formoli Slide location. The total area lost by the removal of these 10 trees is 1,000 sq. ft. Table 1: Other Waters of the U.S. Impacts Identified Impact Type Resource ID Acreage Permanent Other Waters- Ephemeral 0.036 acres Temporary Other Waters- Ephemeral 0.010 acres REVEGETATION MEASURES Revegetation Goal The purpose of the proposed mitigation is to compensate for permanent and temporary effects to other waters of the United States pursuant to the required permits and agreements for the project. Construction implementation will result in removing approximately 1,000 square feet of willow thicket along the ephemeral drainage at PM 5.22 and de-watering and grading the slope to discourage accumulation of water behind the wall, to slow anticipated slope failure. To mitigate for permanent and temporary impacts, the NCRWQCB requested replacement of the willow thicket at a 3:1 ratio. The goal of the revegetation project is to re-establish lost riparian habitat by planting 3,000 sq. ft. of willow species and valley oaks at various sites within the area disturbed by construction. Riparian habitat is often composed of willows, but it can also be composed of other genera, as long as it is within the vicinity of a riparian corridor, on the banks of a creek or river. Non- willow riparian areas are common in inland habitats, as with the Peregrine Slides project. There are valley oaks as well as willows in the riparian corridor in the vicinity of the proposed project. According to A Manual of California Vegetation (2nd Edition), valley oak is endemic to California (Sawyer, Keeler-Wolf, and Evens 2009). Riparian and upland forests of valley oak occur in the deep, rich soil typical of flood plains and valley floors. Riparian stands of valley oak typically exist on higher portions of the floodplain than do stands of Fremont cottonwood (Populus fremontii) and willows. What remains of these forests are only remnants of what once existed in the Central Valley, other valleys, and foothill locations in California. 3 Peregrine Slides Repair Project (EA 01-0B500/EFIS 0112000133) Revegetation Plan, September 2015 Revegetation Methods All disturbed areas will receive permanent erosion control composed of locally appropriate California native grasses and forbs and a non-persistent annual grass. The erosion control seed mix will be specified by Caltrans Landscape Architect in conjunction with the Revegetation Specialist. Typically revegetation plantings are installed approximately one year after construction to allow the soil to settle and establishment of micro-site conditions. Visibility of micro-site conditions allows for more appropriate selection and placement of species during planting. For this project, early revegetation with willow sprigging will occur at the end of construction to have the contractor install willows behind the Peregrine Slide Wall within the contour of the regraded channel, to aid in stabilizing the slope and erosion control. The contractor will collect willow material from the surrounding area within the Caltrans right of way and install willow cuttings on 3 to 5 foot centers at the end of project construction under the direction of the District Biologist and/or Revegetation Specialist (Figure 1). Caltrans understands the likelihood that the slope above the Peregrine Slide Wall may fail and accepts that credit will likely not be applied toward this planting. In addition to having the Contractor install willows in the regraded channel above the Peregrine Slide Wall, the Contractor will also install willows while RSP is being placed at the outlet of Drainage System 4 (Figure 1). One ton rock is being specified for this outlet. In order for the willows to avoid being damaged by the RSP, the willow cuttings may need to be placed along the edges of the RSP only. This willow installation is considered experimental by Caltrans Revegetation Specialists since hydrology will be drained due to project design, and newly rooting willows will struggle in the typically hot, dry summer months, even with supplemental water. Locally, willows only occur where there are pockets of moisture retained in the soil during summer months. Because the willow planting at Drainage System 4 is considered experimental, Caltrans would like to consider this planting as supplementary. Failure for this planting to survive should not be considered a mitigation failure since it is supplementary; however, if the planting survives, Caltrans would like credit for successful establishment of the planting at Drainage System 4 as riparian mitigation. In addition to the willow planting installed by the contractor, 3,000 sq. ft. of willow cuttings and valley oak trees will be planted along the ephemeral drainages behind the Formoli Wall as riparian mitigation to achieve the 3:1 replacement requirement of riparian habitat removed for construction (Figure 2). Willow cuttings will be installed in patches on 3 to 5 foot centers and intermingled with oaks. Fifty valley oak trees will be planted on at least 20 foot centers with willows in between. An additional option for oak planting includes downslope of post mile 5.11 within the riparian zone relating to the Russian River (Figure 3). The Revegetation Specialist will make the final determination for oak planting locations based on best available habitat and safety for planting and maintenance. Implementation Schedule Willow installation at the culvert outlet of drainage system 4 will take place during construction when RSP is being placed. Permanent erosion control