Relations between wildfire related debris-flow volumes and basin morphology, burn severity, material properties and triggering storm rainfall.

摘要

This study develops models to predict the potential volumes of wildfire-related debris flows as a function of basin morphology, burn severity, material properties and triggering storm rainfall characteristics.; For 56 basins in eight burned areas located in Colorado, Utah and California, debris-flow volumes were estimated by quantifying the amount of material eroded from the main channels in a basin.; These data were used to represent debris flows generated from burned basins in different regions and underlain by different rock types. A series of multiple regression analyses indicated that the variables that are most strongly related to debris-flow volume are storm rainfall total, basin area burned at moderate and high severity and basin area with slopes greater or equal than 30% gradient. An evaluation of the models created indicates that the best model to estimate potential wildfire-related debris-flow volumes can be expressed by the equation; ln debris flow volume (ln m 3) = 0.65(ln basin area with slopes greater than or equal to 30% (ln km2)) + 0.86(basin area burned at moderate and high severity (km2))1/2 + 0.22(total storm rainfall (mm)) 1/2 + 6.46, R2 = 0.83, residual standard error = 0.90 . (Abstract shortened by UMI.)