Wildfire effect on forest rainfall infiltration and runoff: a cellular automata-based simulation

Abstract

A storm event-based simulation system is developed to reproduce the effects of wildfire on a predefined forest area's rainfall infiltration and runoff. The simulation system reproduces individual surface cell slope, infiltration capacity, and hydrophobicity. A cellular automaton represents space and time. The Horton equation reproduces infiltration capacity evolution. Different equation parameters account for precipitation intensity variations. Infiltration volume and runoff velocity are computed at the cell level. A Digital Elevation Model reproduces the topography. A real rainfall event is reproduced for a section of La Primavera Forest in Jalisco, Mexico. For a subwatershed within the area of interest, wildfire effects are shown on infiltration, overland flow and outlet discharge throughout the rainfall event. It is shown that rainfall infiltration for wildfire affected terrain is lower and that overland flow and outlet discharge is higher. Infiltration and runoff dynamics at a surface cell depend on storm profile, cell slope, cell soil texture, and overall topography. Water dynamics on the area of interest are shown with a movie effect. It is concluded that a cellular automaton-based model can reproduce infiltration and runoff for different soil texture, topographic and rain conditions. This simulation system is geared for an optimisation system to pinpoint the locations of a series of forest land remediation controls that or maximise infiltration or minimise runoff.