San Juan National Forest
U.S. Forest Service
15 Burnett Court
Durango, CO 81301
September 4, 2018
SPRING CREEK POST-FIRE BAER ASSESSMENT REPORT SUMMARY
The Spring Creek Fire started on June 27, 2018, and is located approximately 5 miles northeast of Ft. Garland, Colorado. As of July 16, the fire burned 108,046 acres with 9,837 acres of Forest Service System (NFS) land, 12,266 acres of Bureau of Land Management (BLM) land, 3,867 acres of state land, and 82,076 acres on private land. Dominant vegetation types within the NFS burned area include mixed-conifer, lodgepole pine, aspen, bristlecone or limber pine, and Gambel oak. These types extend onto BLM and private lands on the east slope of the burn area. On the western slope are large areas of grasslands, big sagebrush, and pinyon-juniper stands.
The Spring Creek Fire burned area was surveyed and assessed by a Forest Service Burned Area Emergency Response (BAER) team comprised of scientists and specialists. The Forest Service is responsible for addressing risks on NFS land. The BAER team evaluated the burned watersheds to determine post-fire conditions, and identify values-at-risk such as threats to human life and safety, property, and critical natural and cultural resources. In addition to these critical values, other threats were also assessed, such as the risk for increased post-fire flooding, sediment flows, rock slides, hazard trees and noxious weed spread. Proposed emergency stabilization treatments are recommended by the BAER team which reduce these potential threats. The BAER team worked with BLM and Natural Resource Conservation Service (NRCS) watershed emergency response teams and other agencies to facilitate and participate in an assessment of all potential values-at-risk.
The BAER assessment team’s analysis of the burn area and recommended emergency treatments are documented in a Forest Service (FS) Burned-Area 2500-8 Report. This report was submitted to the Regional Forester for the Rocky Mountain Region (Region 2) by the Pike and San Isabel Forest Supervisor for review and funding. The BAER report also provides relevant information that is shared with its inter-agency cooperators to help identify potential threats to lands downstream of the fire.
The following is a summary of the BAER team’s burned area assessment for the Spring Creek Fire:
16 sub-watersheds were analyzed and modeled to compare pre-fire conditions to post-fire predicted response: Badito Cone-Huerfano River, Chavez Arroyo, Dog Springs Arroyo, Headwaters Sangre de Cristo Creek, Headwaters Cucharas River, Headwaters Middle Creek, Indian Creek, Manzanares Creek-Huerfano River, Middle Cree-Cucharas River, North Abeyta Creek, Oak Creek-Huerfano River, Pass Creek, South Abeyta Creek, South Oak Creek, Wagon Creek, and West Indian Creek..
There are approximately 60 miles of perennial streams, 336 miles of intermittent streams, and 153 miles of ephemeral streams.
There are approximately 8 miles of NF system roads, and 5 miles of trails.
The headwaters of Indian Creek and Middle Creek have the highest erosion rates, exceeding 6 tons/acre for a 10-year event. These watersheds have a large portion of the area having burned as high soil burn severity. Most watersheds have erosion rates less than 1 ton/acre for a 2-year runoff event. Elevated soil erosion hazard is only applicable for the first few years following the Spring Creek Fire - until revegetation occurs to stabilize the slopes.
There are about 57,683 (54%) acres of unburned/low soil burn severity, 24,529 (23%) acres of moderate soil burn severity and 25,632 (23%) acres of high soil burn severity.
Soil burn severity is the fundamental indicator used to evaluate post-fire conditions. The soil burn severity categories reflect changes in soil properties from pre- to post-fire and are a key element used to identify post-fire threats. The distribution of unburned, low, moderate, and high soil burn severity levels become a baseline for resource specialists to monitor changes in soil-hydrologic function and vegetative response as the burned watersheds recover. Hydrophobic soil conditions are common within moderate and high burn severity areas and rare in the low burn severity areas.
High and moderate soil burn severity categories have evidence of severe soil heating and the consumption of organic material; the soil seedbank and water infiltration characteristics are reduced. Natural recovery is slower where little or no vegetative ground cover remains, with increased surface water runoff resulting in increased soil erosion. Areas of moderate soil burn severity have viable roots and some soil cover, but may still be vulnerable to erosion on steep slopes. The low to very low soil burn severity areas still have good surface soil structure, intact fine roots and organic matter, and should recover more quickly once revegetation begins and soil cover is re-established.
Identified Values-at-Risk, Threats, and Emergency Conditions
Colorado summer thunderstorms (monsoons) have the greatest likelihood of generating large runoff and soil erosion events. If large summer thunderstorms occur, the primary values-at-risk within the burned area are human life and safety, transportation infrastructure (roads and motorized trails), cultural resources, and native vegetation communities. The primary threats caused by the fire include 1) increased runoff, which is expected to intensify the first 2-3 years following the fire until the burned watersheds recover, and 2) accelerated hillslope erosion as a result of increased runoff and decreased infiltration rates. High intensity, short duration rainfall may result in downstream flooding and localized debris flows. Additional threats originating from the destabilized hillslopes throughout the burned area include falling trees and debris flows.
Emergency post-fire conditions for the Spring Creek Fire were identified by the BAER team for the following on-forest values-at-risk:
Human Life and Safety: There is increased risk for the general public to be impacted by rolling rocks, flooding, landslides, debris flows, and hazardous trees along roads and trails.
Property: There is increased risk to FS roads, stream crossings, FS trails, water diversion and conveyance infrastructure, and cadastral markers within the burned area from post-fire impacts of increased water, sediment, and/or debris flows. Impacts include damage to the road and trail surface and drainage features and/or loss of access due to severe erosion of the road and trail surface, or deposition of sediment or debris.
Natural Resources: An increased risk is anticipated to native or naturalized plant communities due to the threat from the spread of noxious weeds. The wildfire created conditions conducive to noxious weed spread and establishment by reducing competition, and exposing bare mineral soil.
There is increased risk to water quality for domestic and agricultural uses, soil productivity and hydrologic function, fisheries and aquatics, and Canada Lynx habitat due to flooding, sedimentation, erosion, and/or debris flows within and adjacent to the burned NFS lands.
Cultural/Heritage Resources: An increased risk is anticipated to prehistoric and historic cultural sites due to the threat of predicted increased flood flows, erosion and sediment, and potential debris flows.
Emergency Stabilization Treatments
The BAER assessment team’s emergency stabilization objectives for the burned areas are to protect, mitigate and reduce the potential for identified post-fire threats, including increased water run-off flows, soil erosion/sediment yield, loss of road access, introduction and expansion of invasive plant species, and falling burned trees, for:
Human life, safety, and property within and downstream of the burned area;
Forest Service infrastructure and investments such as roads and motorized trails;
Critical natural and cultural resources; and
Native and naturalized plant communities from new noxious weed infestations.
The following post-fire emergency stabilization measures and treatments have been approved:
Install burned area warning signs to caution forest visitors traveling and recreating within the burned area.
Implement temporary road and trail closures to prevent public access to at-risk areas within the burned area to protect human life and safety.
To minimize risk to human life and safety, temporarily close dispersed recreation sites in the Indian Creek Road and Tracy Canyon Road areas which are undeveloped campsites that usually are occupied for tent camping.
Storm-proof and stabilize NFS transportation roads and stream crossings with improved water drainage structures and features to prevent damage resulting from post-fire watershed conditions such as soil erosion, storm water run-off, and public safety hazards to improve the safety of forest visitors and employees. Conduct storm patrol monitoring to ensure stream crossings and road treatments are functioning as intended.
Storm-proof and stabilize NFS trails and trailheads with improved water drainage structures and features to prevent damage resulting from post-fire watershed conditions. Conduct storm patrol monitoring to ensure crossings and trail treatments are functioning as intended.
Assist cooperators, including local, county, state, and federal agencies with the interpretation of BAER assessment findings to identify potential post-fire impacts to communities and private land owners, domestic and agricultural water supplies, and public utilities (such as power lines, state roads, county roads, and other infrastructure).
Continue to work and coordinate with interagency cooperators, partners, and affected parties and stakeholders.
Continue to communicate risks to the public, community groups, and cooperating agencies.
Conduct early detection surveys and rapid response eradication with herbicide application on noxious weeds along areas disturbed by fire suppression activities, equipment concentration points, high and moderate soil burn severity areas near these fire suppression disturbed areas, and other high priority areas, to reduce the potential for impaired native vegetative recovery and the introduction and spread of invasive weeds.
Locate, identify and preserve the location of land survey monuments that are at risk from the effects of the fire.
SPECIAL NOTE: Everyone near and downstream from the burned areas should remain alert and stay updated on weather conditions that may result in heavy rains over the burn scars. Flash flooding may occur quickly during heavy rain events. Current weather and emergency notifications can be found at the National Weather Service website: www.weather.gov/pub/.