This tool can be used to pre-process a digital elevation model (DEM) prior to being used for hydrological analysis. It will remove topographic depressions and apparent dams in the DEM in order to enforce continuous flow. This is achieved by breaching through topographic barriers. As such, depression breaching provides an alternative to depression filling. Unlike depression filling, which has one unique solution for each depression, there may be several competing solutions for depression breaching. This tool uses a cost-distance criteria for deciding upon the breach target, i.e. the cell to which the tool will trench a connecting path, and for determining the breach path itself. As such, the trenched path will not necessarily follow a straight line, but rather, will follow a path of lowest cost, where the cost is determined by the amount of change made to the original DEM.
The following is an example of a Python script that uses this tool:
wd = pluginHost.getWorkingDirectory()
inputFile = wd + "DEM.dep"
outputFile = wd + "output.dep"
maxBreachLength = "50.0"
maxElevationDecrement = "not specified"
minElevationDrop = "not specified"
args = [inputFile, outputFile, maxElevationDecrement, minElevationDrop]
pluginHost.runPlugin("BreachDepressions", args, False)
This is a Groovy script also using this tool:
def wd = pluginHost.getWorkingDirectory()
def inputFile = wd + "DEM.dep"
def outputFile = wd + "output.dep"
def maxBreachLength = "50.0"
def maxElevationDecrement = "10.0"
def minElevationDrop = "0.15"
String[] args = [inputFile, outputFile, maxElevationDecrement, minElevationDrop]
pluginHost.runPlugin("BreachDepressions", args, false)