ALLOCATING RESOURCES TO LARGE WILDLAND FIRES - A MODEL WITH STOCHASTIC PRODUCTION-RATES

Wildland fires that grow out of the initial attack phase are responsible for most of the damage and burned area. We model the allocation of fire suppression resources (ground crews, engines, bulldozers, and airdrops) to these large fires. The fireline at a given future time is partitioned into homogeneous segments on the basis of fuel type, available resources, risk, and other factors. Each is assigned a utility value corresponding to the importance of holding the segment. For a given resource allocation, the probability of holding the segment is modeled in terms of the (random) width of fireline built. The task is then to find the allocation that maximizes the expected total utility. With certain restrictions, it proves possible to formulate the optimization as a linear programming problem. Use of the model is demonstrated with a case study of a large fire representative of conditions on the Los Padres National Forest in southern California. One feature is that different assumptions about the uncertainty in the predictions of constructed fireline widths can lead to differences in the optimal resource allocations. Thus, if one inappropriately took the uncertainty to be zero (the deterministic case), the resulting allocation may well not be the optimal one. This illustrates the potential advantage of probabilistic modeling over the previous deterministic approach.