Supplemental Environmental Assessment to the Programmatic Environmental Assessment for Recurring Actions in Arizona, California, and Nevada Stabilization and Revegetation of Hood Mountain Sonoma County, California HMGP # 4344-0302-33 September 2020 U.S. Department of Homeland Security 1111 Broadway, Suite 1200 Oakland, California 94607 This document was prepared by CDM Smith 220 Montgomery Street, Suite 1418 San Francisco, CA 94104 Contract No. HSFE60‐15‐D‐0015 Task Order No. 70FA6018F00000056 Table of Contents 1 Introduction ............................................................................................................................. 1 1.1 Scope of Document .......................................................................................................... 1 1.2 Purpose and Need for the Action ..................................................................................... 1 2 Description of the Proposed Action and Alternatives ............................................................. 2 2.1 No Action Alternative ...................................................................................................... 2 2.2 Proposed Action ............................................................................................................... 2 3 Affected Environment and Environmental Consequences ...................................................... 8 3.1 Resources Not Present ...................................................................................................... 9 3.2 Geology, Soils, and Topography ...................................................................................... 9 3.3 Air Quality...................................................................................................................... 10 3.4 Water Resources ............................................................................................................. 11 3.4.1 Surface Water and Groundwater ............................................................................. 11 3.4.2 Wetlands ................................................................................................................. 11 3.4.3 Floodplains .............................................................................................................. 12 3.5 Biological Resources ...................................................................................................... 12 3.5.1 Terrestrial and Aquatic Habitat ............................................................................... 12 3.5.2 Threatened and Endangered Species ...................................................................... 13 3.5.3 Migratory Birds ....................................................................................................... 13 3.5.4 Invasive Species ...................................................................................................... 14 3.6 Historic Properties and Archaeological Resources ........................................................ 14 3.7 Socioeconomics .............................................................................................................. 15 3.8 Public Services and Recreation ...................................................................................... 15 3.9 Transportation ................................................................................................................ 16 3.10 Noise ........................................................................................................................... 17 3.11 Hazardous Materials and Wastes ................................................................................ 17 3.12 Visual Resources ........................................................................................................ 17 3.13 Cumulative Impacts .................................................................................................... 18 4 Best Management Practices, Minimization, and Mitigation Measures ................................. 18 4.1 Geology, Geohazards, and Soils .................................................................................... 18 4.2 Air Quality...................................................................................................................... 18 4.3 Biological Resources ...................................................................................................... 19 4.4 Cultural Resources ......................................................................................................... 19 4.5 Public Services and Recreation ...................................................................................... 20 Supplemental Environmental Assessment Federal Emergency Management Agency HMGP 4344-0302-33R Page i September 2020 4.6 Noise............................................................................................................................... 20 4.7 Hazardous Materials and Wastes ................................................................................... 20 5 Conclusion ............................................................................................................................. 20 6 References ............................................................................................................................. 21 List of Tables Table 1: Target Plant Species ......................................................................................................... 6 Table 2: Evaluation Criteria for Potential Impacts ......................................................................... 8 Table 3: Project Area Soils ............................................................................................................. 9 List of Figures Figure 1: Project Area ..................................................................................................................... 3 Figure 2: Treatment Areas .............................................................................................................. 4 Figure 3: Trail System .................................................................................................................... 5 List of Appendices Appendix A: ESA No Effect Determination Form Supplemental Environmental Assessment Federal Emergency Management Agency HMGP 4344-0302-33R Page ii September 2020 Acronyms APE Area of Potential Effect Cal OES California Governor’s Office of Emergency Services CFR Code of Federal Regulations CHRIS California Historical Resources Information System CNDDB California Natural Diversity Database CO carbon monoxide CRHR California Register of Historical Resources EFH Essential Fish Habitat EO Executive Order EPA U.S. Environmental Protection Agency FEMA Federal Emergency Management Agency FIGR THPO Federated Indians of Graton Rancheria Tribal Historic Preservation Office FIRM Flood Insurance Rate Map HMGP Hazard Mitigation Grant Program IPaC Information for Planning and Consultation NAHC California Native American Heritage Commission NAVD88 North American Vertical Datum of 1988 NHPA National Historic Preservation Act NRCS Natural Resources Conservation Service NMFS National Marine Fisheries Service NOX nitrogen oxide NRHP National Register of Historic Places NWI National Wetlands Inventory O3 ozone PM particulate matter PEA Final Programmatic Environmental Assessment for Recurring Actions in Arizona, California, and Nevada SEA Supplemental Environmental Assessment SHPO State Historic Preservation Office Supplemental Environmental Assessment Federal Emergency Management Agency HMGP 4344-0302-33R Page iii September 2020 U.S.C. United States Code USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey VOC volatile organic compound Supplemental Environmental Assessment Federal Emergency Management Agency HMGP 4344-0302-33R Page iv September 2020 1 Introduction The U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) proposes to provide federal financial assistance to the County of Sonoma Regional Parks Department (County or Subrecipient), through the California Governor’s Office of Emergency Services (Cal OES or Recipient), for a wildfire mitigation project. The project would be funded under FEMA’s Hazard Mitigation Grant Program (HMGP). The County is proposing to implement erosion and sediment control measures, along with revegetation, on land in Hood Mountain Regional Park, which was affected by the 2017 Nuns Fire in Sonoma County (Proposed Action). Hood Mountain Regional Park is a public park managed by Sonoma County. The project area includes 22.5 acres of the park that straddles the watershed divide between Santa Rosa Creek and Sonoma Creek. The project latitude and longitude are 38.463303, −122.566505. 1.1 Scope of Document This Supplemental Environmental Assessment (SEA) evaluates the range of potential environmental impacts if the Proposed Action is implemented and evaluates the applicability of the December 2014 Final Programmatic Environmental Assessment for Recurring Actions in Arizona, California, and Nevada (PEA) and the March 2019 Supplemental Environmental Assessment to the Final Programmatic Environmental Assessment for Recurring Activities in Arizona, California, and Nevada. FEMA prepared this SEA because the type of action proposed under the Proposed Action does not fall under the range of actions evaluated in the PEA. However, FEMA determined that the activities conducted under the Proposed Action are similar to the activities evaluated in the