Three Years of Hillslope Sediment Yields Following the Valley Complex Fires, Western Montana.

摘要

The 2000 Bitterroot Valley wildfires provided an opportunity to measure post-fire effects and recovery rates. The authors established 24 small (0.01 ha (0.02 acre)) plots in four high-severity burn sites. The authors measured sediment yields at each site with silt fences. They also measured rainfall characteristics, soil water repellency, vegetative cover, and other site characteristics. The median sediment yield in post-fire year 1 was 8 Mg ha-1 yr -1 (3.6 ton acre-1 yr -1), and values ranged from 0.3 to 47 Mg ha-1 yr -1 (0.1 to 21 ton acre-1 yr -1). Sediment yields were lower in post-fire years 2 and 3, with medians of 2 and 0.3 Mg ha-1 yr -1 (0.9 and 0.1 ton acre-1 yr -1), respectively. The high variability in sediment yields was related to 10-minute maximum rainfall intensity (I10), but not to soil water repellency or vegetative cover. The results of this study may assist in decisions about post-wildfire land management.