Disturbed WEPP is a web application which allows users easily to describe numerous disturbed forest and rangeland erosion conditions. The interface presents the probability of a given level of erosion occurring the year following a disturbance. Version 2.0 needs no vegetation calibration.
In the past decade, management of western forests has focused on reduction of fuel loads to reduce wildfire severity, and in most cases this involves forest thinning. Erosion from thinning is likely to come from disturbances to the forest floor, such as compaction (increasing runoff) and creation of roads and skid trails. Forest management is also likely to change the fire return interval and subsequently the erosion patterns.
The Disturbed WEPP interface can be used by a manager who wants to evaluate the impacts of forest management on erosion and sediment delivery. Disturbed WEPP allows users to describe numerous disturbed forest and rangeland erosion conditions, including low and high severity burns.
The general approach is to estimate the level of erosion from an undisturbed forest, and then the erosion from a wildfire using Disturbed WEPP. The post-wildlfire erosion rate is then divided by the frequency of wildfire to get an “average” erosion rate that is added to the undisturbed forest to estimate the background level.
Erosion rates associated with thinning, harvesting, and prescribed fire are also estimated, averaged, and added in, with the wildfire erosion rate possibly being modified assuming it will be less frequent or severe after thinning.
Output provides mean annual runoff depth, erosion rates, sediment yields, and the probability of a given amount of erosion occurring during the year following a disturbance.
Annual sediment delivery with several different return periods.
Disturbed WEPP Model 2.0