contributing_area: Contributing area for a storm of fixed duration
In tabrasel/WetlandTools: General utility functions for TerrainWorks

contributing_area

R Documentation

Contributing area for a storm of fixed duration

Description

Provide a SpatRaster giving the upslope contributing area to each cell of a DEM for shallow subsurface groundwater flow to the cell. D-infinity flow paths are traced upslope from each cell using a spatially variable Darcy velocity (v = k*sin(gradient)) dependent on the specified (spatially uniform) saturated hydraulic conductivity and the gradient of each DEM cell.

Usage

contributing_area(
  input_file = "nofile",
  raster = "nofile",
  dem = "none",
  length_scale = 0,
  k = 0,
  d = 0,
  scratch_dir = "none"
)

Arguments

`input_file`	Character string: a "partial" input file (optional). If no input file is specified and no other arguments are present, a Windows Explorer window opens for file selection.
`raster`	Character string: file name (full path) for an existing contributing-area raster to read from disk (optional).
`dem`	Character string: The file name (full path) of the dem (elevation raster) for construction of an input file.
`length_scale`	Numeric (dbl): Length scale in meters over which to smooth the DEM. This is the length used to measure gradient, curvature, and guide flow directions.
`k`	Numeric (dbl): Uniform saturated hydraulic conductivity for construction of an input file.
`d`	Numeric (dbl): Storm duration (dbl) in hours. Used for construction of an input file for program partial.
`scratch_dir`	Character string: A scratch directory where temporary files are written. If an input file for program partial is created, it is written here.

Details

Contributing_area operates in one of three modes, depending on the input arguments:

As a wrapper for the Fortran "partial" executable, with an existing "partial" input_file.
As a wrapper for program partial, but with the input file constructed by contributing_area.
To read existing raster files from disk.

In modes 1 and 2, contributing_area calls program partial, which creates the requested rasters and writes them to disk as floating point binary files. These are then read and returned by contributing_area as a SpatRaster object. In mode 3, existing raster files are read directly from disk and returned as a SpatRaster object.