Lockheed Fire Post Fire Risk Assessment

Lockheed Fire Post Fire Risk Assessment San Mateo-Santa Cruz Unit California Department of Forestry and Fire Protection September 30, 2009 Aerial photo of Mill Creek drainage August 25, 2009 Table of Contents Page # Executive Summary 1 Introduction and Incident History 1 Watersheds 3 Field Observations 3 Burn Severity Characteristics 8 Fire Behavior 8 Historic Fire Return Intervals 9 Seasonal Context 10 Geology 12 General Observations 13 County Road 13 Downstream Impacts 13 Description of Geologic Units 16 Soils 17 Hydrophobic Soil Conditions 19 Soil Erosion Potential 20 Ecological Impacts 21 Redwood Forest 25 Mixed Conifer 25 Chaparral 26 Coastal Scrub 27 Grassland 27 Specific/Isolated Forest Stands 28 Invasive Species 29 General Recommendations 31 Recommendations to Mitigate Potential Soil Erosion and the Impacts 33 of Storm Water Runoff/Flooding Specific Observations 37 References 51 Post Fire Restoration Do’s and Don’ts 54 Firescaping and Erosion Control with Native Plants 59 Sample No Trespassing Sign 64 Maps Page # Watershed Map 6 Burn Severity Map 7 Fire History Map 11 Geology Map 15 Soil Map 18 Vegetation Type Map 24 Risk Maps Archibald Creek 40 Bettencourt Creek 41 Big Creek 42 Boyer Creek 43 Little Creek 44 Lower Scotts Creek 45 Mill Creek 46 Molino Creek 47 Queseria Creek 48 Upper Scotts Creek 49 Winter Creek 50 Tables and Charts Page # Table 1. Percent of Watersheds Burned 3 Table 2. Ranked Watersheds 5 Table 3. Fire Behavior 9 Table 4. Burn Severity by Vegetation Type 22 Chart 1. Lockheed Fire Severity by Vegetation Type 23 Chart 2. Vegetation Types by Burn Severity 23 Table 5. Generalized model of post-fire vegetation recovery for 27 chaparral Burn Site Evaluation Summary 61 Burn Site Evaluation Forms 66 Executive Summary The Lockheed Fire started on August 12, 2009. During the emergency incident CAL FIRE officials determined that very high burn impacts occurred that could potentially impact lives and property. CAL FIRE assembled a multi-disciplinary team to do a rapid assessment of the fire area and identify critical risk areas. CAL FIRE also determined that local experts have a lot of knowledge from past fires and resource assessments that have been done in Santa Cruz County. This report attempts to bring together information and knowledge related to the potential post fire risks. Based on the assessments made, eleven recommendations were formulated. The recommendations are listed in order of most immediately critical. The number one recommendation and highest priority is for the community accessed from Swanton Road to participate in Emergency Evacuation Planning. There is a significant increase in the potential for flooding, debris torrents, and debris flows in the watersheds affected by the fire. The number two recommendation is for the areas identified in this report as high risk areas to have site specific analysis conducted that prescribe practices to minimize risks. Introduction and Incident History The California Department of Forestry and Fire Protection (CAL FIRE) assembled a team to conduct a post burn assessment as part of its Emergency Watershed Protection (EWP) program authorized by Public Resources Code Section 4675 and 4676. The intent of activities conducted under this authority is to: 1) conserve water and soil, and 2) prevent destructive floods. This report is an assessment of the fire area that ranks high risk areas to life and property and recommends treatments to minimize risk. This report is also a practical guide for property owners regarding recommended actions after a fire. The report contains summary information on watershed data regarding vegetation types, geology, soils and burn severity by watershed. This information can be used as a basis to conduct more detailed investigations and research within the burn area. The data for the maps were a cooperative project between Cal Poly Swanton Pacific Ranch, Big Creek Lumber Company, CAL FIRE and the U.S. Forest Service Remote Sensing Applications Center. The Lockheed Incident (CA-CZU-007246) began on August 12, 2009. The incident was declared contained on August 23, 2009. The total acreage burned was 7,819 acres. The total suppression cost was over 30 million dollars. The fire burned across multiple private ownerships as well as a portion of California State Park property, all within State Responsibility Lands (SRA). The major landowners within the fire were Lockheed Martin Corporation, Big Creek Lumber, Cal Poly Swanton Pacific Ranch and CEMEX. The majority of the fire was located in the Scotts Creek Watershed, which supports anadromous fish bearing streams, with federally endangered coho salmon (Oncorhynchus kisutch) and federally threatened steelhead (Oncorhynchus mykiss). Vegetation types in the burned area include redwood forest, mixed conifer forest, chaparral, coastal scrub and grassland. The landscape is mountainous with slope Page 1 steepness commonly exceeding 50% (slopes range from nearly zero percent to over 90%). Crystalline igneous and sedimentary rocks that are moderately to pervasively fractured dominate the bedrock in the area. Burn severity across the entire burn area was estimated to be 14% very high, 37% high, 43% moderate, and 6% low. On August 31, 2009, a team was assembled to develop a rapid assessment of the burned area watersheds. The objectives of the team were as follows: 1. Estimate the acreage and percent of area burned within each watershed affected by the fire and fire suppression activities. 2. Estimate the burn severity and create a burn severity map using the Burned Area Reflectance Classification (BARC) Map provided by the USDA Forest Service, post burn air photos and ground truthing. 3. Field check areas for hydrophobic soil conditions. 4. Estimate percent of area burned and severity by vegetation type. 5. Evaluate soil erosion potential. 6. Evaluate condition of roads, dams, bridges and culverts that may contribute to flood events (including Swanton Road). 7. Identify problem/risk areas. 8. Develop recommendations to mitigate potential high priority hazards. 9. Develop recommendations to assist restoration efforts. The following technical specialists comprised the assessment team: Angela Bernheisel, CAL FIRE, Forester Richard Casale, NRCS1, Erosion and Sediment Control Specialist Nadia Hamey, Big Creek Lumber, Forester Grey Hayes, PhD, Ecological Consultant Michael Huyette, CGS2, Engineering Geologist Rich Sampson, CAL FIRE, Division Chief Additional experts who worked with the team to produce GIS maps were: John Martinez, CAL FIRE, Pre-Fire Planner Drew Perkins, Cal Poly Swanton Pacific Ranch, GIS Specialist Russ White, Cal Poly Swanton Pacific Ranch, GIS Specialist 1 U.S. Department of Agriculture, Natural Resources Conservation Service 2 California Department of Conservation, California Geological Survey Page 2 Watersheds The main drainages impacted by the fire are listed below (Table 1). All are tributaries to Scott Creek except Davenport Landing, Molino Creek, Picnic Creek and San Vicente Creek. Table 1. Percent of Watersheds Burned Watershed Total Area Area Burned Area Burned (ac) (ac) (%) Archibald Creek 421 369 87.7 Bettencourt Subwatershed 3 495 494 99.8 Big Creek 5856 1447 24.7 Boyer Subwatershed 4 1354 432 31.9 Davenport Landing 2009 7 0.4 Little Creek 1306 1200 91.9 Lower Scotts Creek 1503 150 10.0 Mill Creek 2404 1626 67.6 Molino Creek 1025 797 77.8 Picnic Subwatershed 5 177 142 80.2 Queseria Creek 399 360 90.3 San Vicente Creek 6961 121 1.7 Upper Scotts Creek 5207 583 11.2 Winter Creek 116 94 81.0 Entire Scott Creek Watershed 19,001 6755 36% Field Observations The assessment team made field observations within and immediately adjacent to the Lockheed Fire. Field observations were completed from August 31st to September 2nd. Active suppression operations were still in progress. The team’s focus was to assess high risk areas for flooding and land sliding and to identify potential Emergency Watershed Protection Program projects. Tests for water repellency and hydrophobic 6 soil conditions were conducted at the field sites using a procedure suggested by the NRCS. Where homes or property were found to be at risk, a detailed form developed by the CGS was completed, including a detailed site description and/or photographs of the area. The team utilized incident maps and other maps developed for the assessment. Lidar imagery of the Scotts Creek Watershed was provided by Cal Poly and Big Creek Lumber which was extremely valuable for the geological and hydrological assessments. The team 3 Bettenccourt Creek is separated from the Upper Scott Creek Watershed 4 Boyer Creek is separated from the Big Creek Watershed 5 Picnic Creek is separated from the San Vicente Watershed 6 Hydrophobic conditions result from a waxy substance that is released by plant material during a hot fire. This material penetrates into the soil as a gas and cools, forming a waxy coating around the soil particles (DeBano et al. 1998). Water repellency was evaluated by measuring the time it takes for water droplets to penetrate the soil both on and below the soil surface. Page 3 also conducted informal interviews with residents of the fire area who provided information about past flood events and watershed conditions. The Lockheed Fire Damage Assessment Report (2009) documented all structures observed within the burn and surrounding area where structures were defended. Road and foot inspections were conducted in the areas with high value from August 31 to September 2, 2009. Houses, in-stream structures such as dams, and road-related features, such as culverts and bridges, were surveyed at major drainage crossings. The portions of the burn area that drain into the San Vicente Creek and Davenport Landing watersheds were not evaluated due to their small relative percentage of burn area (1.8% and 0.4%, respectively) and the lack of known nearby values at risk. There is a major water intake for the town of Davenport above the confluence of Picnic Creek and San Vicente Creek.

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