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Topic: hydrology

Tool Description
r.basins.fill Generates watershed subbasins raster map.
r.carve Generates stream channels. Takes vector stream data, transforms it to raster and subtracts depth from the output DEM.
r.drain Traces a flow through an elevation model or cost surface on a raster map.
r.fill.dir Filters and generates a depressionless elevation map and a flow direction map from a given elevation raster map.
r.flow Constructs flowlines. Computes flowlines, flowpath lengths, and flowaccumulation (contributing areas) from a elevation raster map.
r.lake Fills lake at given point to given level.
r.path Traces paths from starting points following input directions.
r.sim.sediment Sediment transport and erosion/deposition simulation using path sampling method (SIMWE).
r.sim.water Overland flow hydrologic simulation using path sampling method (SIMWE).
r.solute.transport Numerical calculation program for transient, confined and unconfined solute transport in two dimensions
r.stream.extract Performs stream network extraction.
r.terraflow Performs flow computation for massive grids.
r.topidx Creates a topographic index (wetness index) raster map from an elevation raster map.
r.topmodel Simulates TOPMODEL which is a physically based hydrologic model.
r.uslek Computes USLE Soil Erodibility Factor (K).
r.usler Computes USLE R factor, Rainfall erosivity index.
r.water.outlet Creates watershed basins from a drainage direction map.
r.watershed Calculates hydrological parameters and RUSLE factors.
r3.flow Computes 3D flow lines and 3D flow accumulation.

See also the corresponding keyword for additional references:

hydrology

  • r.accumulate - Calculates weighted flow accumulation, subwatersheds, stream networks, and longest flow paths using a flow direction map.
  • r.basin - Morphometric characterization of river basins
  • r.basins.fill - Generates watershed subbasins raster map.
  • r.carve - Generates stream channels. Takes vector stream data, transforms it to raster and subtracts depth from the output DEM.
  • r.curvenumber - Generates the Curve Number raster from the landcover and hydrologic soil group rasters
  • r.drain - Traces a flow through an elevation model or cost surface on a raster map.
  • r.fill.dir - Filters and generates a depressionless elevation map and a flow direction map from a given elevation raster map.
  • r.findtheriver - Find the stream pixel nearest the input coordinate
  • r.flow - Constructs flowlines. Computes flowlines, flowpath lengths, and flowaccumulation (contributing areas) from a elevation raster map.
  • r.flowaccumulation - Calculates flow accumulation from a flow direction raster map using the Memory-Efficient Flow Accumulation (MEFA) parallel algorithm by Cho (2023).
  • r.flowfill - Moves water downhill into pools or the ocean/map edge
  • r.gsflow.hydrodem - Creates hydrologically correct MODFLOW DEM from higher-res DEM
  • r.gwflow - Numerical calculation program for transient, confined and unconfined groundwater flow in two dimensions.
  • r.hand - Performs Height Above Nearest Drainage (HAND) analysis and flood inundation mapping with HAND method.
  • r.hazard.flood - Fast procedure to detect flood prone areas.
  • r.hydro.flatten - Derive elevation of water bodies for hydro-flattening
  • r.hydrobasin - Delineates a large number of watersheds using the Memory-Efficient Watershed Delineation (MESHED) OpenMP parallel algorithm by Cho (2025).
  • r.hydrodem - Hydrological conditioning, sink removal
  • r.lake - Fills lake at given point to given level.
  • r.lake.series - Fills lake at given point(s) to given levels.
  • r.landscape.evol - Simulates the cumulative effect of erosion and deposition on a landscape over time.
  • r.lfp - Calculates the longest flow paths from a flow direction raster map and a outlets vector map using the Memory-Efficient Longest Flow Path (MELFP) OpenMP parallel algorithm by Cho (2025).
  • r.path - Traces paths from starting points following input directions.
  • r.richdem.breachdepressions - Breaches depressions using RichDEM
  • r.richdem.filldepressions - Floods depressions using RichDEM
  • r.richdem.flowaccumulation - Calculates flow accumulation via one of a variety of methods.
  • r.richdem.resolveflats - Directs flow from flat areas on depression-filled DEMs
  • r.sim.sediment - Sediment transport and erosion/deposition simulation using path sampling method (SIMWE).
  • r.sim.water - Overland flow hydrologic simulation using path sampling method (SIMWE).
  • r.sim.water.mp - Overland flow hydrologic simulation using path sampling method (SIMWE).
  • r.solute.transport - Numerical calculation program for transient, confined and unconfined solute transport in two dimensions
  • r.stream.basins - Delineates basins according stream network. Input can be stream network, vector point map with outlets or outlet coordinates.
  • r.stream.channel - Calculates local parameters for individual streams.
  • r.stream.distance - Calculates distance to and elevation above streams and outlet. The module can work in stream mode where target are streams and outlets mode where targets are outlets.
  • r.stream.extract - Performs stream network extraction.
  • r.stream.order - Calculates Strahler's and more streams hierarchy. Basic module for topological analysis of drainage network.
  • r.stream.segment - Divides network into near straight-line segments and calculate its order.
  • r.stream.slope - Calculates local parameters for slope subsystem.
  • r.stream.snap - Snap point to modelled stream network. Input can be stream network, point vector map with outlets or outlet coordinates.
  • r.stream.stats - Calculates Horton's statistics for Strahler and Horton ordered networks created with r.stream.order.
  • r.stream.variables - Calculation of contiguous stream-specific variables that account for the upstream environment (based on r.stream.watersheds).
  • r.stream.watersheds - Sub-watershed and sub-stream delineation based on the drainage direction and a gridded stream network.
  • r.subdayprecip.design - Computes subday design precipitation totals.
  • r.terraflow - Performs flow computation for massive grids.
  • r.threshold - Find optimal threshold for stream extraction
  • r.topidx - Creates a topographic index (wetness index) raster map from an elevation raster map.
  • r.topmodel - Simulates TOPMODEL which is a physically based hydrologic model.
  • r.traveltime - Estimation of travel times/isochrones. Computes the travel time of surface runoff to an outlet
  • r.uslek - Computes USLE Soil Erodibility Factor (K).
  • r.usler - Computes USLE R factor, Rainfall erosivity index.
  • r.water.outlet - Creates watershed basins from a drainage direction map.
  • r.wateroutlet.lessmem - Creates watershed basins from a drainage direction map.
  • r.watershed - Calculates hydrological parameters and RUSLE factors.
  • r.width.funct - Calculates the Width Function of a watershed basin.
  • r3.flow - Computes 3D flow lines and 3D flow accumulation.
  • r3.gwflow - Numerical calculation program for transient, confined groundwater flow in three dimensions.
  • v.gsflow.export - Export databse tables and pour point for GSFLOW input and control files
  • v.gsflow.gravres - Set parameters for GSFLOW Hydrologic Response Units (HRUs)
  • v.gsflow.grid - Builds grid for the MODFLOW component of GSFLOW
  • v.gsflow.hruparams - Set parameters for GSFLOW Hydrologic Response Units (HRUs)
  • v.gsflow.mapdata - Upload data to PRMS data
  • v.gsflow.reaches - Build stream "reaches" that link PRMS segments to MODFLOW cells
  • v.gsflow.segments - Prepares stream segments for PRMS and GSFLOW
  • v.stream.inbasin - Subset a stream network into just one of its basins
  • v.stream.order - Compute the stream order of stream networks stored in a vector map at specific outlet vector points