Evaluating the effectiveness of postfire rehabilitation treatments

Robichaud, P.R.; Beyers, J.L.; Neary D.G. 2000. Evaluating the Effectiveness of Postfire Rehabilitation Treatments. Gen. Tech. Rep. RMRS-GTR-63. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 85 p.

Keywords: burn severity, erosion control, BAER, burned area emergency rehabilitation, mitigation, seeding, monitoring

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Abstract: 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.

Moscow FSL publication no. 2000n