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1.22 Wildfire Mitigation Report
WILDFIRE MITIGATION REPORT Spring Valley Ranch LLC Glenwood Springs, Colorado 2022 Update February 2022 Prepared By: ANCHOR POINT GROUP 2131 Upland Ave. Boulder, CO 80304 © Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Contents INDEX OF TABLES .......................................................................................................................................................... 3 EXECUTIVE SUMMARY ................................................................................................................................................ 1 INTRODUCTION .............................................................................................................................................................. 2 Project Objectives.......................................................................................................................................... 2 Location ......................................................................................................................................................... 2 Climate .......................................................................................................................................................... 4 WILDFIRE MITIGATION ................................................................................................................................................ 5 Wildfire Mitigation Objectives....................................................................................................................... 5 Current Risk Situation ................................................................................................................................... 5 Fire Regime and Condition Class ................................................................................................................. 7 Fire Behavior Modeling ................................................................................................................................ 9 Fire Behavior Inputs .................................................................................................................................... 10 Fuel Models and Fire Behavior ................................................................................................................... 13 Fire Behavior Outputs ................................................................................................................................. 21 Fire Behavior Interpretation and Limitations ............................................................................................. 27 WILDFIRE MITIGATION RECOMMENDATIONS ..................................................................................................... 29 Section 504 Class 1 Ignition Resistant Construction .................................................................................. 37 Justification ................................................................................................................................................. 38 APPENDIX A .................................................................................................................................................................. 39 FIRE BEHAVIOR POTENTIAL ANALYSIS METHODOLOGY ......................................................................................................................... 39 Purpose ........................................................................................................................................................ 39 Model Description ....................................................................................................................................... 39 BEHAVE ...................................................................................................................................................... 40 FlamMap ..................................................................................................................................................... 40 Reference Guide ............................................................................................................................................................... 41 TABLE OF FIGURES FIGURE 1. SPRING VALLEY RANCH NEAR GLENWOOD SPRINGS, COLORADO .................................................................................3 FIGURE 2. RECENT LARGE FIRE PERIMETERS MAP .................................................................................................................................6 FIGURE 3. CONDITION CLASSES MAP ..........................................................................................................................................................7 FIGURE 4. FIRE BEHAVIOR MODELING ........................................................................................................................................................9 FIGURE 5. PERCENT SLOPE ........................................................................................................................................................................... 10 FIGURE 6. ASPECT ........................................................................................................................................................................................... 11 FIGURE 7. ELEVATION ................................................................................................................................................................................... 12 FIGURE 8. SPRING VALLEY RANCH FUEL MODELS .............................................................................................................................. 14 FIGURE 9. ANNUAL GRASSES/FORBS......................................................................................................................................................... 15 FIGURE 10. SAGE AND GRASS MIX ............................................................................................................................................................ 16 FIGURE 11. GAMBLE OAK OVER SIX FEET TALL .................................................................................................................................. 17 FIGURE 12. ASPEN .......................................................................................................................................................................................... 18 FIGURE 13. MIXED CONIFER AND DOUGLAS-FIR STANDS ................................................................................................................. 19 FIGURE 14. RATE OF SPREAD PREDICTIONS (MODERATE WEATHER CONDITIONS) ...................................................... 21 FIGURE 15. RATE OF SPREAD PREDICTIONS (EXTREME WEATHER CONDITIONS) ......................................................... 22 FIGURE 16. FLAME LENGTH PREDICTIONS (MODERATE WEATHER CONDITIONS) ........................................................ 23 FIGURE 17. FLAME LENGTH PREDICTIONS (EXTREME WEATHER CONDITIONS) .......................................................... 24 FIGURE 18. CROWN FIRE (MODERATE WEATHER CONDITIONS) .................................................................................. 25 FIGURE 19. CROWN FIRE (EXTREME WEATHER CONDITIONS) ..................................................................................... 26 FIGURE 20. Defensible Space and Easements ........................................................................................................................................ 30 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 FIGURE 21. Fuels Treatments…..…………………………………………………………………………………......31 FIGURE 22. AND 23. ANNUAL MOWING FUELS REDUCTION AREAS ................................................................................................ 32 FIGURE 24. FUEL MODEL GS1 / GS2............................................................................................................................ 32 FIGURE 25. PROPERTY EDGE FUEL BREAK .............................................................................................................................................. 33 FIGURE 26. FUEL TREATMENTS ................................................................................................................................................................... 34 FIGURE 27. SPECIAL BUILDING CONSTRUCTION PROPERTIES ........................................................................................................... 36 INDEX OF TABLES TABLE 1. MONTHLY CLIMATE SUMMARY FOR GLENWOOD SPRINGS ...................................................... 4 TABLE 2. CONDITION CLASS DESCRIPTIONS ..................................................................................................... 8 TABLE 3. REFERENCE WEATHER USED IN THE FIRE BEHAVIOR POTENTIAL EVALUATION ............. 20 iii 1 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 EXECUTIVE SUMMARY The Spring Valley Ranch Wildfire Mitigation Report Update, February 2022, has been created to meet initial and long-range development planning goals for the built environment and open space, to ensure ecosystem and community sustainability and to integrate directives with social goals. Specific project goals are to: • Reduce the risk of catastrophic wildfire • Provide development options for the mitigation of wildfire • Develop an integrated management approach that encompasses all natural communities represented at Spring Valley Ranch • Provide a tool to help residents of Spring Valley Ranch understand the complexity of the ecosystem and more effectively protect their property from potential wildfires Vegetation management is needed throughout the upper montane zone of the western slope of the Colorado Rocky Mountains to return forests and rangelands to an ecologically sustainable condition and to reduce the potential for catastrophic wildfire and insect epidemics. Vegetative conditions at the Spring Valley Ranch property are significantly divergent from their historic norm. A comprehensive evaluation of wildfire hazard within Spring Valley Ranch was conducted; findings should be integrated into the overall restoration prescriptions being developed for the property. Project-wide vegetation restoration treatments include the maintenance of meadows, strategic fuel breaks to reduce vegetation density primarily through selective cutting to remove undesirable species and retention of mature healthy plants, and implementation of prescribed burning where feasible. Other recommended actions include the utilization of ignition resistant construction for all homes built in the development, in combination with individual defensible space. Glenwood Springs Rural Fire Protection District is the authority having jurisdiction and dictates water supply requirements. Other infrastructure recommendations are proposed to meet adopted code compliance. The overall intent of this plan is to look, holistically, at the built and natural environments to create a sustainable development that is in concert with sound ecological principles while remaining fire resistant. 2 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 INTRODUCTION Statement of Needs The Spring Valley Ranch Wildfire Mitigation Report was created to meet medium and long- range development planning goals, to mitigate the risk of wildfire, ensure that management activities are ecologically sustainable, and to integrate these directives with social and development preferences. This plan provides specific management direction to ensure the sustainability of the development and serve as a management guide for open space. Project Objectives The three main objectives of the Spring Valley Ranch Wildfire Mitigation Report are to: 1) Provide a Wildfire Mitigation Report for development review and approval. 2) Help ensure the support of the Glenwood Springs Rural Fire Protection District. 3) Provide a tool for current and future residents of Spring Valley Ranch to understand the complexity of the Spring Valley Ranch wildfire issue so that they can more effectively manage their property in relation to this ecosystem. Location The proposed Spring Valley Ranch development is located approximately 20 miles southeast of Glenwood Springs, Colorado and covers 5,237 acres (Figure 1). Spring Valley Ranch is accessed by County Road 114 (Spring Valley Road). 3 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 1. Spring Valley Ranch near Glenwood Springs, Colorado 4 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Climate Garfield County has mountain climate, temperature, and precipitation, which vary with altitude and aspect. Higher elevations are typically cooler and receive more moisture; northern aspects are cooler than southern aspects. Climatic data for the area are presented below. Table 1. Monthly Climate Summary for Glenwood Springs (053359) NCDC 1971 - 2000 Monthly Normals The percent of possible observations for period of record: Max. Temp.: 90.5% Min. Temp.: 90.3% Precipitation: 91.7% Snowfall: 87.7% Snow Depth: 41.6% Retrieved Feb 2022 from GLENWOOD SPGS #2, COLORADO - Climate Summary (dri.edu) 5 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 WILDFIRE MITIGATION Wildfire Mitigation Objectives 1) Mitigate the risk of severe, uncontrollable wildfires by managing surface fuels and enhancing open meadow areas. 2) Promote responsible development through FireWise Concepts. 3) Develop a holistic fire management package which includes: a. Fuels Reduction b. Construction Materials c. Defensible Space 4) Minimize impacts to soils and the environment throughout the mitigation process. Current Risk Situation For the purposes of this report, the following definitions apply: Risk is considered to be the likelihood of an ignition occurrence. This is primarily determined by the fire history of the area. Hazard is the combination of the wildfire hazard ratings of the WUI communities and fire behavior potential, as modeled from the fuels, weather and topography of the study area. The majority of the study area is at high risk for wildland fires. This assessment is based on an analysis of the following factors: • The Spring Valley Ranch area is defined by mostly moderate and high wildfire risk by the Colorado State Forest Atlas: Wildfire Risk Assessment Public Viewer (coloradoforestatlas.org) • The Glenwood Springs area has a significant fire history. Major fires in the area since 1994 include the South Canyon (Storm King Mountain), Coal Seam, Spring Creek, South Grizzly, Thompson Creek, Dotsero, Panorama, Coffee Pot, Black Mountain (West on I- 70),Center Mountain fires and more recently the Lake Christine (2018) and Grizzly Creek (2020) (see Figure 2). The South Canyon Fire (1994) resulted in the largest loss of life to wildland firefighters of any fire in the western United States in the last century. The Grizzley Creek Fire burned approximately 32,000 acres and impacted the northeast corner of the development. The influence of this fire on the development will be fully assessed during the summer 2022 update. While some of this data cannot be directly extrapolated to the Spring Valley Ranch development, enough of the same conditions exist to make a reasonable assumption of significant risk. 6 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 2. Recent Large Fire Perimeters Map 7 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Fire Regime and Condition Class A system's historical range of variability provides a window for understanding the conditions and processes that sustained ecosystems prior to significant human alteration.1 These reference conditions serve as a guide for establishing future goals that will protect ecological systems and meet societal objectives.2 Reference conditions serve as a guide for restoration of current landscape conditions to improve ecological sustainability and mitigate wildfire and post fire erosion hazards.3 The fire-regime condition class (FRCC) is an expression of the departure of the current condition from the historical fire regime. It is used as a proxy for the probability of severe fire effects (e.g., the loss of key ecosystem components - soil, vegetation structure, species; or alteration of key ecosystem processes - nutrient cycles, hydrologic regimes). Consequently, FRCC is an index of risk to the status of many components (e.g., water quality, fish status, wildlife habitats, etc.). Figure 3 graphically displays the return interval and condition class of the study area. Figure 3. Condition Classes Map Deriving fire-regime condition class entails comparing current conditions to some estimate of the historical range that existed prior to substantial settlement by Euro Americans. The departure of the current condition from the historical base line serves as a proxy to likely ecosystem effects. 1 Swanson et al. 1994. 2 Kaufmann et al. 1994, Kaufmann et al. 1998, Landres et al. 1999, Moore et al. 1999, Morgan et al. 1994. 3 Kaufmann et al. 2000a. 8 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 When applying the condition class concept, we assume that historical fire regimes represent the conditions under which the ecosystem components within fire-adapted ecosystems evolved and have been maintained over time. Thus, if we project that fire intervals and/or fire severity has changed from the historical conditions, we expect that fire size, intensity, and burn patterns would also be subsequently altered if a fire occurs. Furthermore, we assume that if these basic fire characteristics have changed, then it is likely that there would be subsequent effects to those ecosystem components that had adapted to the historical fire regimes. As used here, the potential of ecosystem effects reflects the probability that key ecosystem components may be lost should a fire occur. A key ecosystem component can represent virtually any attribute of an ecosystem (for example, soil productivity, water quality, floral and faunal species, large-diameter trees, snags, etc.). The following classes of condition are used to qualitatively rank the potential of effects to key ecosystem components: Table 2. Condition Class Descriptions Condition Class Condition Class Description 1 Fire regimes are within their historical range and the risk of losing key ecosystem components as a result of wildfire is low. Vegetation attributes (species composition and structure) are intact and functioning within an historical range. Fire effects would be similar to those expected during historical times. 2 Fire regimes have been moderately altered from their historical range. The risk of losing key ecosystem components as a result of wildfire is moderate. Fire frequencies have changed by one or more fire-return intervals (either increased or decreased). Vegetation attributes have been moderately altered from their historical range. Consequently, wildfires would likely be larger, more intense, more severe, and have altered burn patterns than that expected during historical times. 3 Fire regimes have changed substantially from their historical range. The risk of losing key ecosystem components is high. Fire frequencies have changed by two or more fire-return intervals. Vegetation attributes have been significantly altered from their historical range. Consequently, wildfires would likely be larger, more intense, more severe, and have altered burn patterns than that expected during historical times. Together, reference conditions and current conditions are used to identify desired future conditions, which are ecologically sustainable and congruent with desired land uses. Parameters that require evaluation include vegetation density, fuel load, fire return interval, species composition, landscape distribution, age distribution and habitat value. Monitoring and adaptive 9 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 management are necessary to ensure that goals are met. Adaptive management is a critical component of ecological restoration because ecosystems are constantly changing in both time and space. Fire Behavior Modeling Fire behavior modeling provides a landscape level assessment of wildland fire hazards within the project area. Potential fire behavior was analyzed in order to determine which areas are most likely to burn and with what intensity. A BehavePlus simulation was run to compute potential fire behavior characteristics over the entire landscape for constant weather and moisture conditions. BehavePlus is a nationally recognized methodology for estimating a fire’s intensity and rate of spread given topography, fuels, and weather conditions. In order to model potential fire behavior across the project area, GIS data layers including elevation, slope, aspect, fuel models and canopy closure were utilized in FlamMap (see Figure 4). This modeling procedure yields three maps: 1) rate of spread, 2) flame length and 3) crown fire activity. These output maps illustrate the potential for fire behavior for the entire project area; they are used to prioritize treatment areas and guide fuel treatments, which in turn reduce fire intensity. Two fire scenarios were modeled for the property, one under moderate conditions and one under extreme conditions. Figure 4. Fire Behavior Modeling 10 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Fire Behavior Inputs Fire behavior is dependent upon aspect, slope, elevation, canopy cover and fuel type. Figure 5. Percent Slope Slopes are shown here as percent (rise/run x100). Steeper slopes intensify fire behavior and thus will contribute to a high wildfire hazard rating. Spread rate of a fire for a slope of 30% are typically double those of flat terrain when all other influences are equal. For these and other fire behavior rationales, many of the fuels reduction projects targeted these steeper slopes. 11 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 6. Aspect Aspects are shown as degrees from North ranging from 0 to 360 according to their orientation. Aspects are influential in the type and quantity of vegetative fuels. Fuels on south facing slopes tend to be drier and more lightly loaded than fuels on north facing slopes when all other influences are equal. Aspect also has an influence on species dominance. 12 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 7. Elevation Elevations within the study area vary from approximately 6,900 feet to over 9,300 feet. As elevation increases, fuel loading and species change. Above tree line, fuels become sparse, and the natural burn interval is measured in centuries. 13 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Fuel Models and Fire Behavior Fuel models are a set of numbers that describe fuels in terms that a fire behavior model can use. There are seven characteristics that are used to categorize fuel models. • Fuel Loading • Size and Shape • Compactness • Horizontal Continuity • Vertical Arrangement • Moisture Content • Chemical Content The study area is represented primarily by 6 fuel models GR2 (grass) GS1,GS2, (Grass Shrub) SH7 (shrub) TU1 and TU5 (timber-understory). Each of the major fuel types present in the study area are described below in terms of the characteristics that coincide with that fuel model. Fuel model descriptions are taken from Scott and Burgan’s Standard Fire Behavior Fuel Models (FBFM40): A Comprehensive Set for Use with Rothermel’s Surface Fire Spread Model4, a national standard guide to fuel modeling. Vegetation for the project area may or may not be specifically listed in the description. Plant species are only an aid to help visualize the characteristics of the model. The photos are taken from the project area and show where the local vegetation fits in. 4 Scott, Joe H.; Burgan, Robert E. 2005. Standard fire behavior fuel models: a comprehensive set for use with Rothermel’s surface fire spread model. Gen. Tech. Rep. RMRS-GTR-153. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station 14 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 8. Spring Valley Ranch Fuel Models 15 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 FUEL MODEL GR2 Figure 9. Annual Grasses/Forbs Characteristics Grasslands and savanna are represented along with stubble, grass-tundra, and grass-shrub combinations. Common Types/Species Annual and perennial grasses are included in this fuel model. Fire Behavior Fire spread is governed by the fine, very porous, and continuous herbaceous fuels that have cured or are nearly cured. Fires in this fuel model are surface fires that move rapidly through the cured grass and associated material. Very little shrub or timber is present, generally less than one-third of the area. 16 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 FUEL MODEL GS1 / GS2 Figure 10. Sage and Grass Mix Characteristics Open shrub lands and pine stands or scrub oak stands that cover one-third to two-thirds of the area may generally fit this model; such stands may include clumps of fuels that generate higher intensities and that may produce firebrands. Scattered sage within grasslands and some pinyon- juniper may be in this model. Common Types/Species Other tree and shrub species include common and Rocky Mountain juniper, buckbrush, sage, bitter brush, and mountain mahogany. Mountain grasses are included in this model. Fire Behavior Fire spread is primarily through the fine herbaceous fuels, either curing or dead. These are surface fires where the herbaceous material, in addition to litter and dead-down stem wood from the open shrub or timber overstory, contribute to the fire intensity. 17 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 FUEL MODEL SH7 (Extreme Condition) Figure 11. Gamble Oak Over Six Feet Tall Characteristics This model consists of stands of small diameter trees or large shrubs with continuous closed crowns. There may be high amounts of small dead limbs retained on the lower portion of trees. There may also be high amounts of woody and needle litter associated with the stand. Common Types/Species Stands of mature shrubs, six or more feet tall, such as California mixed chaparral, and Scrub Oak stands. Fire Behavior High rates of spread can be experienced in this model. Fire is carried through the foliage as well as the fine live and dead woody material of tree crowns. Fire spread is also enhanced by the amount of dead woody material on the ground. 18 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 FUEL – TU1 Figure 12. Aspen Characteristics Hardwoods that have leafed out support fire in the compact litter layer. This layer is mainly needles, leaves, and occasionally twigs because little undergrowth is present in the stand. Amounts of needle and woody litter are also low. Common Types/Species Plains Cottonwood and several species of willows along riparian areas are represented here. There are mostly streamside understory plants that do not contribute to the fire intensity. Fire Behavior Fires in this fuel model are slow burning, low intensity fires burning in surface fuels. Fuels are mainly needles and woody litter. Heavier fuel loadings from old dead and down trees or branches can cause flare-ups. Heavier fuel loads have the potential to develop crown fires in extreme burning conditions. 19 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 FUEL MODEL TU 5 Figure 13. Mixed Conifer and Douglas-fir Stands Characteristics This model is represented by dense stands of over-mature Ponderosa pine, Lodgepole pine, mixed conifer, and continuous stands of Douglas-fir. In all stand types, heavy down material is present. There is also a large amount of dead, down woody fuels. Reproduction may be present, acting as ladder fuels. This model includes stands of budworm killed Douglas-fir, closed stands of Ponderosa pine with large amounts of ladder and surface fuels and stands of Lodgepole pine with heavy loadings of downed trees. This model can occur from the foothills through the sub- alpine zone. Common Types/Species All types of vegetation can occur in this model, but primary species are, Douglas-fir, Ponderosa pine, and Lodgepole pine. Fire Behavior Fire intensities can be moderate to extreme. Fire moves through dead, down woody material. Torching and spotting are more frequent. Crown fires are quite possible. 20 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 The weather inputs for FlamMap were created by using weather data collected at Rifle Remote Automated Weather Station (RAWS). It was determined that this RAWS site provided the best option for weather data for the project area. Table 3. Reference Weather Used in the Fire Behavior Potential Evaluation Rifle Information Weather observations from the Rifle (RAWS) were sorted by spread component for a ten-year period (May to October 2000-2021) to calculate these conditions. The moderate conditions class (16th to 89th percentile) was calculated for each variable (1 hour, 10 hour, and 100 hour fuel moisture, woody fuel moisture, herbaceous fuel moisture, and wind speed) using Fire Family Plus. This weather condition class most closely represents an average fire season day. The extreme conditions class was calculated in Fire Family Plus using 97th percentile weather data. That is to say, the weather conditions existing on the two to three most severe fire weather days were sorted by spread component for each season for the ten-year period. It is reasonable to assume that similar conditions may exist for at least three days of the fire season during an average year. In fact, during extreme years, such conditions may exist for significantly longer periods. Even these calculations may be conservative compared to observed fire behavior. The following values were used in FlamMap: Average Weather Conditions Variable Value 20ft wind speed (upslope) 17 Herbaceous fuel moisture (%) 4 (30) Woody fuel moisture (%) 70 1hr Fuel moisture 3 10hr Fuel moisture 4 100hr Fuel moisture 7 Latitude (dd mm ss) 39 ° 30' 51 " N Longitude (dd mm ss) 107 °45 ' 26 " W Elevation (ft.) 6,120 21 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Fire Behavior Outputs From the fire behavior analysis predictions of rate of spread and flame length are derived. The maps graphically display the outputs of FlamMap for both moderate and extreme weather conditions. Figure 14. Rate of Spread Predictions (Moderate Weather Conditions) 22 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 15. Rate of Spread Predictions (Extreme Weather Conditions) Spread rate values are generated by the FlamMap model and classified into four categories based on standard ranges: 0-20 CPH (chains/hour), 20.1-40 CPH, 40.1-60 CPH, and greater than 60 CPH. A chain is a logging measurement that is equal to 66 feet. One mile equals 80 chains. 1 CPH equals approximately 1 foot/minute. 23 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 16. Flame Length Predictions (Moderate Weather Conditions) 24 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 17. Flame Length Predictions (Extreme Weather Conditions) Flame length values are generated by the FlamMap model and classified in the four categories based on standard ranges: 0-4 feet, 4.1-8 feet, 8.1-12 feet and 12.1-60 feet. Flame lengths of 4 feet and less are acceptable for direct attack by hand crews. Flame lengths of 8 feet and less are suitable for direct attack by machinery. With flame lengths of greater than 8 feet, indirect and aerial attacks are the preferred methods. 25 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 18. Crown Fire (Moderate Weather Conditions) 26 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 19. Crown Fire (Extreme Weather Conditions) Crown fire activity values are generated by the FlamMap model and classified into four categories based on standard ranges: active, passive, surface and not applicable. In the surface fire category, little or no tree torching will be expected. During passive crown fire activity, isolated torching of trees or groups of trees will be observed, and canopy runs will be limited to short distances. During active crown fire activity, sustained runs through the canopy will be observed that may be independent of surface fire activity. 27 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Fire Behavior Interpretation and Limitations The lower elevations of the study area are dominated by shrubs and grass. The most significant factor in fire behavior for this type of fuel is wind. Under extreme conditions, all the fuel models burn with high intensity and great speed. In order for fire to move through the area, it needs continuous fuels. In years with good moisture a higher fuel load of grass can be expected and as grasses cure, they can become a problem later in the season. In dry years, or during drought conditions, the grass will be very sparse and there will be mostly bare ground between the shrubs. Shrubs can appear green and still burn well due to volatile oils in the leaves and bark. Shrubs will also have dead wood that may not be seen due to the leaf canopy. Because most of the shrubs lose their leaves in the fall, the threat for late fall and winter fires is very low. If there is good moisture in the spring, the shrubs will not burn until much later in the summer. Gamble oak is especially dangerous as it has a waxy coating on the leaves that promotes intense burning under the proper conditions. Dense stands scattered throughout the central and southern portions of the development pose the greatest threat from wildfire. Many of these stands are located below planned home sites, making proper defensible space and ignition resistant home construction of critical importance. The rate of spread under moderate conditions is quite fast, reaching two MPH in some areas. Under extreme conditions speeds of one MPH or greater would be common with speeds of up to 10 MPH possible without taking into account fire spread due to spotting. Flame lengths in the oak will generally be too intense for direct attack by hand crews. Steep slopes will also contribute to intensity. Sage varies in its burning intensity by the age and structure of the plants. Areas that are actively browsed will typically be very low growing, have new growth and burn less intensely. As the plant gets older and/or not browsed, it will become decadent with much of the plant dying off and contributing to more intense burning. Under moderate conditions, the fire could be fought by direct attack methods safely. Under extreme conditions, fire will move rapidly through the crowns of the plants, creating spotting problems. Stands of mixed conifers occur in stringers and patches primarily on southwest facing slopes in the eastern portion of the study area. Under extreme conditions this fuel model is capable of producing large flame lengths and dangerously rapid fire spread through spotting. Torching and crown fire runs are possible. Direct attack in this fuel model may not be possible even in moderate burning conditions and will certainly not be possible in extreme conditions. Although this fuel model does not exist as a continuous fuel bed in the study area, conforming defensible space and ignition resistant construction is highly recommended for all homes located in or near these fuels. 28 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Aspen stands do not pose much threat from wildfire. They would most likely be a barrier to fire due to the typically wet conditions existing where dominant and the generally high live fuel moistures in the plants. Even in dry years, aspen will probably not contain enough fuel to carry the fire. Aspen also tends to occur at the higher elevations of the study area where cooler conditions exist. It would be a good idea to clean up diseased and fallen trees in the aspen stands which if left undisturbed could create heavy fuel loads of dead and down material. This evaluation is a prediction of likely fire behavior given a standardized set of conditions and a single point source ignition at every point. It does not consider cumulative impacts of increased fire intensity over time and space. The model does not calculate the probability that a wildfire will occur. It assumes an ignition occurrence for every cell (each 30 x 30 meter area). Weather conditions are extremely variable and not all combinations are accounted for. These outputs are best used for pre-planning and not as a stand-alone product for tactical planning. It is recommended that whenever possible, fire behavior calculations be done with actual weather observations during the fire. It is also recommended that the most current ERC values be calculated and distributed during the fire season to be used as a guideline for fire behavior potential. 29 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 WILDFIRE MITIGATION RECOMMENDATIONS In response to the comprehensive analysis described above, the following elements for creating a FireWise development are suggested. Defensible Space • All homes and common buildings will be required to develop and maintain defensible space. Defensible space includes the use of FireWise vegetative management that removes flammable fuels from around a structure to reduce exposure to radiant heat. The flammable fuels may be replaced with green lawn, gardens, certain individually spaced green, ornamental shrubs, individually spaced and pruned trees, decorative stone or other non-flammable or flame-resistant materials. Although this diagram depicts defensible space in relation to trees, the same zonal approach and general thinning standards still apply. Defensible space should be created in concert with the homeowner and builder’s design aesthetic to create both a pleasing look and fire resistant landscape. An aggressive program of evaluating and implementing defensible space for homes in the highest hazard neighborhoods will do more to limit fire related property damage than any other single recommendation in this report. For this reason, the creation and maintenance of defensible space should be covenant controlled. Defensible Space Easements • All lots with a downhill • exposure (Figure 20) and adjacent to common open space will have a Defensible Space Easement, platted, and accepted in covenants. This area will allow homeowners to extend and maintain their defensible space beyond their property line if an extended distance is required. This area will be covenant restricted to any dumping or disposal of combustible materials or yard waste. 30 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Figure 20. Defensible Space and Defensible Space Easements Fuel Treatments • Fuel Breaks Seven types of fuels reduction treatments (fuel breaks) will be provided for the development (see Figure 21). The intent is to reduce the intensity and rate-of-spread of the fire. The fuel breaks are located in areas where the fire behavior is most affected by topography, prevailing and or continuous fuels. These areas should be delineated as Fuels Reduction Easements on the final plat map and in the development’s covenants. The Golf Course can be excluded from this easement. On-site evaluation will determine what form of treatment is necessary. These fuel break areas would be maintained in addition to each individual defensible space around homes. The fuel breaks leverage off the golf course, roads and or riparian enhancement areas to create a landscape mosaic 31 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 of fuels reduction. The layout and orientation of the fuel breaks considered prevailing winds, likely ignition sources and the fire behavior output maps described above and in Appendix A. Figure 21. Fuels Treatments 32 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Annual Mowing - Mitigation in fuel model GS1 (Figure 22), mixed sage and grass, can often be accomplished by a Hydro-Axe or industrial mower. Annual maintenance of the Sage may only be needed for the first few years. After the Sage has been successfully retarded, the grass can be mowed by more conventional means. This fuels reduction project (Figure 23) creates a “line of defense” to help prevent a grass fire from moving into a more hazardous fuel profile, north of the fuel break line. The project shown in Figure 23 connects the riparian treatment to the golf course. The overall intent of this area is to maintain the grasses to a height of <3” or maintain greenness. Figure 22 and 23. Annual Mowing Fuels Reduction Areas Figure 24. Fuel GS1 / GS2 33 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Fuelbreaks Fuelbreaks shown in dark blue on the main map are prescribed in areas of high to extreme fire behavior in proximity to buildable lots. Their intent is to reduce the intensity and rate- of-spread of fire through these areas. The dark blue treatment shown below is specifically placed on the property line in an effort to mitigate the large fuel bed which extends from the main road, through private property and through the Ranch. There are more efficient and effective areas to treat this fuel bed, outside the property lines, however an area within the property was selected to help ensure control over the fuels reduction project. Figure 25. Property Edge Fuel Break 34 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Linked Defensible Space and Over-Lot Thinning. Over-lot thinning: • For the six lots described in the master fuels reduction map ( light blue), prior to home construction, fuels treatment consistent with Zone 2 as described in the CSFS fact sheet no.6.302 “Creating Wildfire Defensible Zones” summarized below, shall be implemented. Flammable vegetation and materials located wholly or partially within the treatment area shall be treated as follows: o At ground level- remove flammable materials, including but not limited to, ground litter, duff and dead or desiccated vegetation that will propagate fire. o Thin trees and large shrubs so there are at least 10 feet between crowns. Crown separation is to be measured from the furthest branch of one tree to the nearest branch on the next tree. o From 0-10 feet above ground level remove flammable trash, debris or other materials, grass, herbaceous and brush vegetation. All limbs and foliage of living trees shall be removed up to a height of 10 feet or 1/3 the height of the tree or shrub whichever is less. Remove all ladder fuels from under the remaining trees. Linked Defensible Space: • The eight lots that are prescribed for linked defensible space (orange) will create a functional fuel break by linking the eight defensible spaces. This is a critical element as it closes the gap between two major fuels reduction project to the South/West and North/East. An option for these lots would be to conduct over-lot thinning as described above prior to construction. Figure 26. Fuel Treatments 35 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Ignition Resistant Building Requirements Universal Construction Standards All construction within the development will be required to utilize a Class “A” roof covering. Class “A” roof assemblies will not be permitted. Cedar siding and other use for cedar materials on the exterior of the structure will not be permitted. Special Building Construction Properties Lots identified in figure 27 represent those lots which due to their increased fire hazard require additional wildfire mitigation in the form of ignition resistant building construction. Typical Hazardous Fuel Lots were assigned to the Special Building Construction Properties category based on the significant presence of hazardous fuel. This fuel model was determined to be the common denominator in the more hazardous fire behavior outputs of flame length, rate of spread and crown fire potential. Over-lot thinning on these lots to convert the fuel model from one with significant woody components to a grass/shrub fuel would reduce the overall hazard of the property and require the construction to adhere only to the universal construction standards. 36 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Structures built on lots with significant presence of hazardous fuel will be required to comply with Section 504 Class 1 ignition resistant construction as described in the 2018 International Wildland Urban Interface Code. Figure 27 Special Building Construction Properties 37 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Section 504 Class 1 Ignition Resistant Construction as described in the 2018 International Wildland Urban Interface Code. 38 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb. 2022 Justification It is the recommendation of this report that the Wildfire Mitigation Recommendation elements described above be selected by the authority having jurisdiction as the best approach for new development in this area. These recommendations provide the best balance between the critical elements of water, access, fuels reduction and ignition resistant construction. To mitigate the potential for a structure fire extending beyond the building into the wildland and creating a significant event, residential 13D sprinkler systems with the appropriate volume and fire flow for each specific structure are required. If a 13-D system should be disabled or fail and a breach of the structure should occur, defensible space as a fuels reduction technique, to limit fire spread from the structure to the surrounding vegetation, will be installed. A Defensible Space Easement will be established to ensure that the proper defensible space distances are met even beyond individual properly lines on the most critical lots. Class “A” roof coverings will be required. This provides protection, for the most critical area of the house, from ember generation in the event of a wildland fire. The restrictions on the use of Cedar siding and other exterior Cedar projects will help protect all structures from surface fire ignition. From a wildfire perspective, spectrums of solutions for the development are offered. Including geographic fuel breaks adjacent to neighborhoods and structures to reduce the rate of spread and intensity of an encroaching wildfire. Fuel breaks in combination with defensible space are the best solution to keep direct radiant heat and flame contact from igniting structures. The water supply configuration is sufficient for structure protection and wildfire suppression. In most jurisdictions throughout the United States, it is taught and recommended that engines do not hook up to water sources other than to fill their tanks. Mobility is the key to fire suppression in the wildland urban interface. Ample fill sites (pressurized hydrants) will be available. Access standards will adhere to the 2018 UWIC. This code specifies reasonable and practical access standards for the UWI, not the overly restrictive requirements of the Uniform Fire Code (UFC) which were developed for an urban application. Often meeting UFC standards for access in rural areas creates unnecessary and undesirable resource damage. The UWIC access standards are sufficient for fire department access and egress while balancing the need for responsible land development. For these reasons, this report recommends the above stated elements be utilized to provide the most efficient and effective approach for responsible development for the Spring Valley Ranch Project. Environmental Management (Missoula, Montana). 39 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb 2022 APPENDIX A FIRE BEHAVIOR POTENTIAL ANALYSIS METHODOLOGY Purpose The purpose of this appendix is to describe the methodology used to evaluate the threat represented by physical hazards, such as fuels, weather, and topography, to values-at-risk in the study area by modeling their effects on fire behavior potential. Model Description Fire Behavior Flow chart The fire behavior potential analysis represents a relative ranking of locations based upon fire behavior predicted by the model. The model inputs include aspect, slope, elevation, canopy cover, fuel type, canopy bulk density, canopy base height and stand height. The model outputs are determined using FlamMap5 which combines surface fire predictions with the potential for 5 Mark Finney, Stuart Brittain and Rob Seli., The Joint Fire Sciences Program of the Rocky Mountain Research Station (USDA Forest Service, Missoula, Montana), the Bureau of Land Management and Systems for Environmental Management (Missoula, Montana). 40 Spring Valley Ranch Development Wildfire Mitigation Report Update Feb 2022 crown fire development. Calculations for surface fire predictions (rate of spread and flame length) are based on the USDA Forest Service's BEHAVE6 model. BEHAVE The BEHAVE fire behavior prediction and fuel modeling system was utilized to determine surface fire behavior estimates for this study. BEHAVE is a nationally recognized set of calculations used to estimate a surface fire’s intensity and rate of spread given certain conditions of topography, fuels and weather. The BEHAVE modeling system has been used for a variety of applications including prediction of an ongoing fire, prescribed fire planning, fuel hazard assessment, initial attack dispatch and fire prevention planning and training. Predictions of wildland fire behavior are made for a single point in time and space given simple user-defined fuels, weather and topography. Requested values depend on the modeling choices made by the user. Assumptions of BEHAVE: • Fire is predicted at the flaming front • Fire is free burning • Behavior is heavily weighted towards the fine fuels • Continuous and uniform fuels • Surface fires FlamMap Anchor Point uses FlamMap to evaluate the potential fire conditions in the study area. The Spring Valley Ranch development encompasses approximately 5,237 acres (8.2 square miles). The study area for the fire behavior analysis includes the development and a buffer of approximately 804.6 meters (1/2 mile) in all directions broken down into 30-meter (M) grids. Using existing vector and raster spatial data and field data, ArcGIS spatial analysis capabilities are utilized to calculate model inputs for each 30-meter square (MSq) grid. These values are input into FlamMap, along with reference weather and fuel moisture (long-term weather observations statistically calculated from the Rifle Remote Automated Weather Station information). The outputs of FlamMap include the estimated Rate of Spread (ROS) (from BEHAVE), Flame Length (FL) (from BEHAVE) and Crown Fire Activity. The model computes these values for each grid cell in the study area. This evaluation is a prediction of likely fire behavior given a standardized set of conditions and a single point source ignition at every point. It does not consider cumulative impacts of increased fire intensity over time and space. The model does not calculate the probability that a wildfire will occur. It assumes an ignition occurrence for every cell (a 30 x 30-meter area). Weather conditions are extremely variable and not all combinations are accounted for. These outputs are best used for pre-planning and not as a stand-alone product for tactical planning. It is 6 Patricia L. Andrews, producer and designer, Collin D. Bevins, programmer and designer., The Joint Fire Sciences Program of the Rocky Mountain Research Station (USDA Forest Service, Missoula, Montana) and Systems for 41 Spring Valley Ranch Development Wildfire Mitigation Report Update March 2022 recommended that whenever possible, fire behavior calculations be done with actual weather observations during the fire. It is also recommended that the most current ERC values be calculated and distributed during the fire season to be used as a guideline for fire behavior potential. APPENDIX B: Reference Guide Construction in Spring Valley Ranch should be required to follow Ignition Resistant Constructing Class I standards as defined in the 2018 ICC Wildland Urban Interface Code. These construction techniques, in combination with fuels reduction on both the landscape and home- site level, should create a condition where developed property would have a low-to- moderate impact from a moderate intensity wildfire. Additionally, other improvements could be made to further ensure protection from fire. Some of these elements are detailed in these publications from the Colorado State Forest Service: • Home Ignition Zone Guide - 2021_CSFS_HIZGuide_Web.pdf (colostate.edu) • 6.303, Fire-Resistant Landscaping - 06303.pdf (colostate.edu) • 6.305, FireWise Plant Materials - 06305.pdf (colostate.edu) • 6.306, Grass Seed Mixes to Reduce Wildfire Hazard - 06306.pdf (colostate.edu) • Wildfire and Insurance -2021-Wildfire-and-Insurance-Brochure-1.pdf (colostate.edu) • Protecting Your Home from Wildfire: Creating-Wildfire-Defensible-Zones.pdf (landcan.org)