United States Department Of Agriculture Evaluating the Effectiveness Forest Service Of Postfire Rehabilitation Rocky Mountain Research Station Treatments General Technical Report RMRS-GTR-63 Peter R. Robichaud Jan L. Beyers September 2000 Daniel G. Neary Abstract Robichaud, Peter R.; Beyers, Jan L.; Neary, Daniel G. 2000. Evaluating the effectiveness of postfire rehabilitation treatments. Gen. Tech. Rep. RMRS-GTR-63. Fort Collins: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 85 p. Spending on postfire emergency watershed rehabilitation has increased during the past decade. A west-wide evaluation of USDA Forest Service burned area emergency rehabilitation (BAER) treatment effectiveness was undertaken as a joint project by USDA Forest Service Research and National Forest System staffs. This evaluation covers 470 fires and 321 BAER projects, from 1973 through 1998 in USDA Forest Service Regions 1 through 6. A literature review, interviews with key Regional and Forest BAER specialists, analysis of burned area reports, and review of Forest and District monitoring reports were used in the evaluation. The study found that spending on rehabilitation has increased to over $48 million during the past decade because the perceived threat of debris flows and floods has increased where fires are closer to the wildland-urban interface. Existing literature on treatment effectiveness is limited, thus making treatment comparisons difficult. The amount of protection provided by any treatment is small. Of the available treatments, contour-felled logs show promise as an effective hillslope treatment because they provide some immediate watershed protection, especially during the first postfire year. Seeding has a low probability of reducing the first season erosion because most of the benefits of the seeded grass occurs after the initial damaging runoff events. To reduce road failures, treatments such as properly spaced rolling dips, water bars, and culvert reliefs can move water past the road prism. Channel treatments such as straw bale check dams should be used sparingly because onsite erosion control is more effective than offsite sediment storage in channels in reducing sedimentation from burned watersheds. From this review, we recommend increased treatment effectiveness monitoring at the hillslope and sub-catchment scale, streamlined postfire data collection needs, increased training on evaluation postfire watershed conditions, and development of an easily accessible knowledge base of BAER techniques. Keywords: burn severity, erosion control, BAER, burned area emergency rehabilitation, mitigation, seeding, monitoring. The Authors Peter R. Robichaud is a Research Engineer with the Station's Soil and Water Engineering Research Work Unit, and is stationed at the Forestry Sciences Laboratory, 1221 South Main St., Moscow, ID 83843. Jan L. Beyers is a Research Plant Ecologist with the Pacific Southwest Research Station's Prescribed Fire and Fire Effects Research Work Unit, and is stationed at the Riverside Fire Laboratory, 4955 Canyon Crest Dr., Riverside, CA 92507. Daniel G. Neary is a Research Soil Scientist and Project Leader with the Sustainability of Riparian Ecological Systems Research Work Unit and is stationed at the Southwest Forest Science Complex, 2500 S. Pine Knoll, Flagstaff, AZ 86001. The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. Acknowledgments Page Preparation of this report represents a true partnership No Action Review Interview Form ..................22 between Forest Service Research and National Forest Sys- Treatment Actions Interview Form ................ 22 tems staffs. Much of the work of collecting, collating, and Relative Benefits Interview Form ..................22 tabulating the information contained in this report was con- Monitoring Reports ...............................................22 ducted by research assistants J. Tenpas, K. Hubbert, and B. Analysis Methods ..................................................22 Nelson. We could not have completed it without them. The Burned Area Reports and Interview Forms .... 22 cooperation of the six regional Burn Area Emergency Rehabili- Monitoring Reports ........................................23 tation (BAER) coordinators and many Forest BAER team Results ...................................................................23 members was essential to the success of this project, and we Overview of Data Collected ...........................23 gratefully acknowledge their contributions. Funding for the Fire Severity ...................................................23 project was provided by the Forest Service, Watershed and Air Erosion Estimates ...........................................26 Staff, with additional contributions from the Rocky Mountain Hydrologic Estimates ..................................... 27 and Pacific Southwest Research Stations. Risk Analysis ..................................................27 Probability ofSuccess .....................................29 Contents Cost of No Action/Alternatives .......................29 BAER Team Members ....................................30 Page Monitoring Reports ......................................... 30 Introduction ............................................................................1 Treatment Effectiveness Ratings .....................36 USDA Forest Service Burn Area Emergency Hillslope Treatments ................................36 Rehabilitation (BAER) History ................................1 Channel Treatments .................................37 Problem Statement and Objectives ..................................2 Road and Trail Treatments .......................39 Definitions .......................................................................2 Treatment Rankings ........................................39 Literature Review ...................................................................5 Discussion ..............................................................44 Fire's Impact on Ecosystems ............................................5 BAER Assessments......................................... 44 Fire Effects on Watersheds .......................................5 BAER Project Monitoring ...............................46 Water Quality ...........................................................8 Treatment Effectiveness ..................................47 Surface Erosion ........................................................8 Hillslope Treatments ................................47 Sediment Yield and Channel Stability ......................9 Channel Treatments ................................. 52 Mass Wasting ...........................................................9 Road Treatments ......................................53 Dry Ravel ...............................................................11 Conclusions ............................................................53 Emergency Watershed Rehabilitation Recommendations ..................................................54 Treatment Effectiveness .........................................11 References ..............................................................54 Hillslope Treatments ......................................................11 Appendix A-Example Data and Channel Treatments .......................................................20 Interview Forms ................................60 Road Treatments ............................................................21 Appendix B-Treatment Effectiveness Methods ................................................................................21 Summaries .........................................74 Burned Area Report Data ..............................................21 Hillslope Treatments ....................................... 74 Interview Survey ............................................................22 Channel Treatments .........................................79 Project Review Interview Form ..............................22 Road Treatments .............................................83 You may order additional copies of this publication by sending your mailing information in label form through one of the following media. Please specify the publication title and number. Telephone (970) 498-1392 FAX (970) 498-1396 E-mail [email protected] Mailing Address Publications Distribution Rocky Mountain Research Station 240 West Prospect Road Fort Collins, CO 80526 Evaluating the Effectiveness of Postfire Rehabilitation Treatments Peter R. Robichaud Jan L. Beyers Daniel G. Neary Introduction BAER authority integrated the evaluation of fire severity, funding request procedures, and treatment options. Recent large, high severity fires coupled with The occurrence of many large fires in California and subsequent major hydrological events have generated southern Oregon in 1987 caused expenditures for BAER renewed interest in the linkage between fire and onsite and treatments to exceed the annual BAER authorization of $2 downstream effects. Fire is a natural and important million. On several occasions inappropriate requests were disturbance mechanism in many ecosystems. However, the made for nonemergency items, and clarifications were intentional human suppression of fires in the Western issued that defined real emergency situations warranting United States, beginning in the early 1900's, has altered rehabilitation treatments. Policies