Draft Slide Fire Burned Area Emergency Response Report Coconino National Forest, June 24, 2014
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Draft Slide Fire Burned Area Emergency Response Report Coconino National Forest, June 24, 2014 Page 1 of 213 Contents Introduction: .............................................................................................................................................................. 3 Executive Summary: .................................................................................................................................................. 3 Soil Burned Severity and Soil Burn Severity with Strong Hydrophobic Conditions Map: ........................................... 5 Values at Risk and Evaluation:................................................................................................................................... 8 Treatment Narrative and Treatment Objectives: .................................................................................................... 15 Treatment Maps: ..................................................................................................................................................... 22 Burned Area Report 2500-8: .................................................................................................................................... 24 Resource Area Executive Summaries: ...................................................................................................................... 37 Resource Area Complete Reports: ........................................................................................................................... 45 Water Resource Assessment ................................................................................................................................ 45 Geologic Hazard Assessment ............................................................................................................................... 63 Figure 4. Slide Fire BAER Debris Flow Probability Map ....................................................................................... 87 Soil Resource Assessment .................................................................................................................................... 98 Resource Specialty: ENGINEERING/RECREATION/TRANSPORTATION REPORT ................................................... 26 BAER Wildlife Report............................................................................................................................................ 34 Botany Report ...................................................................................................................................................... 58 NOXIOUS/INVASIVE SPECIES ASSESSMENT .......................................................................................................... 69 TECHNICAL SPECIALIST’S REPORT – HERITAGE RESOURCE .................................................................................. 73 MINIMUM REQUIREMENTS DECISION GUIDE WORKBOOK – WILDERNESS AREA .............................................. 84 Page 2 of 213 Introduction: This report details the Burned Area Emergency Response (BAER) teams assessment of the Slide Fire including the burned severity, identification of values at risk, and recommendations for emergency stabilization treatments designed to reduce the risk to life, property, natural and cultural resources associated from post fire storm events. It includes the 2500-8 report, executive summaries of resource specialist’s reports, complete specialists reports and associated maps. The table contents can be linked to the section of interest. Executive Summary: Summary of Analysis, Soil Burn Severity, and Values-at-Risk The Slide Fire burned approximately 22,000 acres on the Flagstaff and Red Rock Districts of the Coconino National Forest in north central Arizona roughly along and west of State Route 89a and Oak Creek Canyon from Sterling Springs hatchery to Slide Rock State Park .The Slide Fire was human caused and burned across moderate to very steep chaparral and ponderosa pine and mixed conifer covered slopes and slopes less than about 40 percent in ponderosa pine dominated vegetation types within the Oak Creek 5th HUC (Hydrologic Unit Code) watershed. The steeper slopes are especially subject to debris flows, rockslides, overland flow and accelerate erosion that could become concentrated flow and in defined drainages potentially producing large floods that could damage and pose risk to forest values (life, property, natural and cultural resources identifed below) and off-Forest private property and county infrastructure. Portions of the burn area are located in the Red Rock Secret Mountain Wilderness. Flatter slope positions at higher elevations in ponderosa pine vegetation types are suited timber base. The burn area adjacent to Oak Creek is heavily used by the recreating public. Approximately 3,115 acres (14 percent) burned at high soil burn severity, 7,067 acres (32 percent) burned at moderate severity, and 10,415 acres (46 percent) burned at low severity and 1,293 acres (6 percent) remain unburned or burned at very low severity. Collectively, about 46% of the fire burned in the moderate or high soil burn severity class. Repeated onsite tests indicate both moderate and high soil burn severity classes have strong hydrophobic soil tendencies that could have high hydrologic response. Average annual sheet and rill soil erosion averages about 30 tons/acre. The 6th HUC watersheds of concern are Upper Oak Creek and West Fork of Oak Creek that include Sterling Spring and the perennial streams West Fork of Oak Creek and Oak Creek. These watersheds and hillslopes drain directly toward forest campgrounds, day use areas, the Sterling Spring Fish Hatchery, cultural sites, an Outstanding Arizona Water (Oak Creek, West Fork of Oak Creek), Side Rock State Park, non-Forest lands including approximately 75 or more homes, public, private and forest roads. Post- fire floods from the 25-year,1 hour rainstorm could be 2 to 8 times pre-fire flows. The time to peak is approximately one half hour, allowing very minimal time to respond once a high precipitation event occurs. The watersheds of concern that rank the highest (50% or greater) in debris flow probability and sediment volume generated are within Upper Oak Creek, West Fork, Unamed Tributary, the lower subbasins of Sterling Canyon. These sub-watersheds have a high proportion of high and moderate burn severity along their channel lengths, have steep headwater basins that were burned at high or moderate severity and had riparian or confer-dominated vegetation in the channels that burned. Within these large watersheds the specific areas of concern are the face drainages of Oak Creek at Pine Flat and from Un named Tributary south to where the fire started. In West Fork, the face drainages from the confluence of Casner Cabin Page 3 of 213 Draw to the confluence of Oak Creek have a high probability of debris flows. Within the face drainages of Oak Creek about 28 stream channels were identified that have a possibility of debris flow occurrence. This would pose a hazard to the public and property along the creek. Post-fire emergency conditions and values at risk from debris flows, mud-ash flows, floods, and rock fall hazards include various Forest Service roads, campgrounds, day use areas and trails, water systems, toilets and recreational activities in West Fork and on Oak Creek within/adjacent to the burned area and downstream of the burned area. The Forest Service facilities could be damaged or covered by debris and mud. Various private property developments that have vented ford crossings over Oak Creek could be damaged by debris flows or flood deposits that would need to be removed. The Sterling Creek Fish hatchery and its water system and facilities is threatened by post-fire debris flows, and flooding. Buildings/homes on the west side of Oak Creek that are on the edge of the burned area could be damaged by rocks, mud, ash and water from rills and gullies developed on burned slopes above the property, debris floods in channels that lead into the property or by hyperconcentrated flood1 deposits from slopes or channels. People recreating along the creeks, trails, campgrounds, day use areas or living at residences or other properties in or adjacent to the Slide Fire area are also threatened by geologic hazards including debris flows, rock fall, mud-ash and flood flows. Soil and water quality is also a value that is threatened by geologic hazards as are various species of wildlife, fisheries and their habitats. A total of 19 eligible or unevaluated archaeological sites are within or immediately adjacent to the Slide Fire. Twelve sites were documented for their post-fire condition. All of the sites above the Mogollon Rim were determined to be at low risk of post-fire storm effects. Six sites within Oak Creek Canyon are being recommended for emergency treatments to mitigate potential adverse effects to significant cultural resources from post fire storm events. Oak Creek Canyon TCP (Traditional Cultural Properties) – The Hopi tribe, Yavapai-Apache Nation, and Yavapai Prescott Indian Tribe have all expressed that Oak Creek Canyon has traditional cultural significance to them. This property has not been formally evaluated, but it has been informally recognized as a TCP by the Forest for management purposes. Twelve wildlife species and their habitat (including 12 Protected Activity Centers) were evaluated for the Slide Fire BAER assessment. Mexican spotted owls are federally threatened and eleven are on the Region