Template:Watershed from Raster

Watershed from Raster

The Watershed from Raster tool derives a watershed and its streams locations from an elevation raster and one or more outlet locations. This is actually a workflow that invokes several tools sequentially. The tools that are invoked include:

• Breach Depressions Least Cost
• Rho8 Flow Directions or D8 Flow Directions (Depending on the selected pre-processing engine)
• D8 Flow Accumulation
• Extract Streams
• Streams from Raster
• Snap Outlet Points to Streams
• Watershed Delineation
• Polygons from Index Raster

After these tools the following operations are performed:

• The basin boundary is smoothed
• The streams are cleaned and trimmed to the basin

Input Parameters

• Input raster – Select the input elevation raster.
• Outlet coverage – Select a coverage containing one or more outlet points close to the watershed and/or sub-basin outlet(s). These points do not need to be directly on a flow accumulation cell since the algorithm searches for the closest stream to the defined outlet locations.
• Threshold area – The threshold area to use for stream or ridge generation.
• Pre-processing engine – Select which pre-processing engine to use.
  • "rho8" – Computes flow directions and accumulations using the Rho8 algorithm.
  • "Whitebox full workflow" – Computes flow directions and accumulations using the Whitebox tool full workflow algorithm that uses a standard D8 method for computing flow directions.

Output Parameters

• Output coverage – Defines the name of the tool-generated output coverage containing the watershed boundary.
• Coverages containing the modified outlet location(s) and the stream locations are also created with this tool. The name of these coverages are currently hardwired to the original raster names with an extension at the end based on the options selected in the tool.
• Breached, Flow direction, and Flow accumulation rasters are also generated from this tool. The names of these are currently hardwired to the original raster names ending in _breached, _flowdir, and _flowaccum respectively. An additional extension is added to the end of the raster name based on the pre-processing engine used.

Current Location in toolbox

Coverages/Watershed from Raster