Monitoring Treatments
In the mid 1990’s, as rehabilitation expenditures continued to escalate, a revision of the federal funding process was implemented that now requires verification that treatments being implemented are minimal, necessary, reasonable, practicable, cost-effective, and will provide significant improvement over natural recovery. However, there were few data that could be used to verify that treatments were worth the cost and would, indeed, provide significant improvement over natural recovery. In the late 1990’s the postfire rehabilitation policies were integrated across several different federal land management agencies and, at the same time, the scope and application of postfire analysis and treatment was broadened to include monitoring to determine if additional treatment is needed and evaluating to improve treatment effectiveness.
Despite expanded land management agency responsibility to verify treatment necessity and monitor treatment effectiveness, the U.S. General Accounting Office (2003) recently reported that postfire mitigation treatments used to reduce runoff and erosion have not been rigorously evaluated to determine if they are meeting treatment objectives. Direct measurement of erosion and/or runoff is expensive, complex, and labor-intensive, and few researchers have done it. Most emergency postfire rehabilitation efforts have been evaluated qualitatively in written reports with some photographic support, but few quantitative data have been collected (Robichaud and others 2000). However, recent scientific efforts have focused on developing and implementing methods that assess the effectiveness and the limitations of specific postfire rehabilitation treatments through direct measurement of watershed processes, such as erosion, runoff, peakflows, sedimentation, etc. In addition, smaller scale, less expensive methods for monitoring treatment effectiveness, such as sediment fence installations (Robichaud and Brown 2002), have been developed for use by both researchers and land managers.
Recent findings show that postfire rehabilitation treatments are not as effective as many land managers believed. Robichaud and others (2000) surveyed 98 postfire rehabilitation specialists from the western U.S. and found that their perceptions of treatment effectiveness were quite varied (Table:Postfire Treatment Effectiveness Ratings). Because of the lack of quantitative data, postfire rehabilitation decisions have been, by necessity, largely based on experience, perceptions, and past practice.
Preliminary analysis of monitoring results suggests that treatment performance may be closely related to storm type and time since the fire. The greatest erosion is generally measured during the first postfire year, which often is an order of magnitude greater than the second postfire year. Recent studies suggest that several factors, some of which have not always been considered, will influence the expected reduction in erosion risk from any given treatment. These include 1) where treatments are applied within a burned area (burn severity), 2) expected rainfall events (intensity, durations, and amounts), 3) topography, 4) soils, and 5) expected natural recovery rate.
Encyclopedia ID: p288
