r.topmodel(1grass)

📦
version 8.5.0 · 10 versions
, in alpine 3.24, ubuntu stonking

✨ NAME ✨

r.topmodel — okay bestie, this one simulates TOPMODEL, which is a physically based hydrologic model. That's the whole thing. That's the name. 💖

Oh also, hi, it's me, the r.topmodel(1grass) manual page — GRASS User's Manual energy, but make it cute. 🎀

🔑 KEYWORDS 🔑

raster, hydrology, model

🦋 SYNOPSIS 🦋

r.topmodel
r.topmodel --help
r.topmodel [-p] parameters=name topidxstats=name input=name output=name
[timestep=integer]   [topidxclass=integer]   [topidx=name]
[ntopidxclasses=integer]   [outtopidxstats=name]   [--overwrite]
[--help]  [--verbose]  [--quiet]  [--ui]

🌈 Flags

  • -p — Preprocess only, and then stop, right after generating outtopidxstats. She's done, she's leaving, don't text her. 💅
  • --overwrite — Allow output files to overwrite existing files. (Yes. She will bulldoze them. That's what you asked for.)
  • --help — Print usage summary. Self-care. 🫶
  • --verbose — Verbose module output. Give me everything, tell me your whole life story.
  • --quiet — Quiet module output. Shhh. 🤫
  • --ui — Force launching GUI dialog. Buttons. Clicks. Iconic.

🌸 Parameters

  • parameters=name [required] — Name of input TOPMODEL parameters file.
  • topidxstats=name [required] — Name of input topographic index statistics file.
  • input=name [required] — Name of input rainfall and potential evapotranspiration data file.
  • output=name [required] — Name for output file.
  • timestep=integer — Time step. Generate output for this time step.
  • topidxclass=integer — Topographic index class. Generate output for this topographic index class.
  • topidx=name — Name of input topographic index raster map. Must be clipped to the catchment boundary. Used for generating outtopidxstats.
  • ntopidxclasses=integer — Number of topographic index classes. Used for generating outtopidxstats. Default: 30.
  • outtopidxstats=name — Name for output topographic index statistics file. Requires topidx and ntopidxclasses.

💖 DESCRIPTION 💖

r.topmodel simulates TOPMODEL, which is a physically based hydrologic model. Periodt.

🧚 Parameters description

parameters

This file contains TOPMODEL parameters that describe the study area. Any lines starting with a # sign or empty lines are ignored. Slay, comments are valid.

# Subcatchment name
Subcatchment 1
################################################################################
# A [m^2]: Total subcatchment area
3.31697E+07
################################################################################
# qs0 [m/h]: Initial subsurface flow per unit area
#         "The first streamflow input is assumed to represent
#          only the subsurface flow contribution in the watershed."
#                                       - Liaw (1988)
0.000075
# lnTe [ln(m^2/h)]: Areal average of the soil surface transmissivity
4.
# m [m]: Parameter controlling the decline rate of transmissivity
# See Beven and Kirkby (1979)
0.0125
# Sr0 [m]: Initial root zone storage deficit
0.0025
# Srmax [m]: Maximum root zone storage deficit
0.041
# td [h]: Unsaturated zone time delay per unit storage deficit if greater than 0
#  OR
# -alpha: Effective vertical hydraulic gradient if not greater than 0.
#
# For example, -10 means alpha=10.
60.
# vch [m/h]: Main channel routing velocity
20000.
# vr [m/h]: Internal subcatchment routing velocity
10000.
################################################################################
# infex: Calculate infiltration excess if not zero (integer)
0
# K0 [m/h]: Surface hydraulic conductivity
2.
# psi [m]: Wetting front suction
0.1
# dtheta: Water content change across the wetting front
0.1
################################################################################
# d [m]: Distance from the catchment outlet
#         The first value should be the mainstream distance from
#         the subcatchment outlet to the catchment outlet.
# Ad_r:  Cumulative area ratio of subcatchment (0.0 to 1.0)
#         The first and last values should be 0 and 1, respectively.
#   d  Ad_r
    0   0.0
 1000   0.2
 2000   0.4
 3000   0.6
 4000   0.8
 5000   1.0

input

This file contains observed weather data. The receipts, literally.

# dt [h]: Time step
24
################################################################################
# R [m/dt]:  Rainfall
# Ep [m/dt]: Potential evapotranspiration
# R             Ep
0.000033        0.000000
0.000053        0.011938
0.004821        0.000000
.
.
.

timestep

If a timestep is specified, output will be generated for the specific time step in addition to the summary and total flows at the outlet. This parameter can be combined with topidxclass to specify a time step and topographic index class at the same time. If no topidxclass is given, output will be generated for all the topographic index classes. 🌈

toptoidxclass

If a topographic index class is specified, output will be generated for the given topographic index class. This parameter can be combined with timestep. If no timestep is given, output will be generated for all the time steps. 👑

topidx, ntoptopidxclasses, outtoptidxstats

The topidx map can optionally be used for creating a new topographic index statistics file. This map has to be already clipped to the catchment boundary. The entire range of topographic index values will be divided into ntoptopidxclasses and the area ratio of each class will be reported in the outtoptidxstats file. These three parameters can be omitted unless a new topidxstats file needs to be created. No cap. 🎀

⚠️ Bestie note: those three go together like a trio of besties at the mall — it's all-or-nothing vibe-wise, and they're optional unless you need a fresh topidxstats.

📚 REFERENCES 📚

  • Beven, K. J., 1984. Infiltration into a class of vertically non-uniform soils. Hydrological Sciences Journal 29 (4), 425-434.
  • Beven, K. J., Kirkby, M. J., 1979. A physically based, variable contributing area model of basin hydrology. Hydrological Sciences Bulletin 24 (1), 43-69.
  • Beven K. J., R. Lamb, P. Quinn, R. Romanowicz, and J. Freer, 1995. TOPMODEL, in V.P. Singh (Ed.). Computer Models of Watershed Hydrology. Water Resources Publications.
  • Cho, H., 2000. GIS Hydrological Modeling System by Using Programming Interface of GRASS. Master’s Thesis, Department of Civil Engineering, Kyungpook National University, South Korea.
  • Liaw, S. C., 1988. Streamflow Simulation Using a Physically Based Hydrologic Model in Humid Forested Watersheds. Dissertation, Colorado State University, CO. p163.
  • Morel-Seytoux, H. J., Khanji, J., 1974. Derivation of an equation of infiltration. Water Resources Research 10 (4), 795-800.

👀 SEE ALSO 👀

r.fill.dir, r.mapcalc, r.topidx

How to run r.topmodel

👑 AUTHORS 👑

Huidae Cho, Hydro Laboratory, Kyungpook National University, South Korea

Based on TMOD9502.FOR by Keith Beven.

🌟 SOURCE CODE 🌟

Available at: r.topmodel source code (history)

Latest change: Wednesday Oct 15 09:25:39 2025 in commit:

6dc7fccce023d644aa085662ac87fd341d31575f

Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

Okay that's the whole page, we ate and left no crumbs 💅✨ — this was r.topmodel(1grass) from the GRASS User's Manual, running GRASS 8.5.0, last touched in that commit on Wednesday Oct 15 09:25:39 2025. Go simulate a watershed, bestie, you got this 🦋🌸

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