1. General Model Information

Name: catchment water discharge and soil water


Main medium: terrestrial
Main subject: hydrology
Organization level: Ecosystem
Type of model: not specified
Main application: research
Keywords: basin hydrologic model, infiltration, ET, subsurface flow,overland flow, basin scale, spatially distributed, soil moisture, evapotranspiration, catchment water discharge,


Prof. Keith Beven
Hydrology and Fluid Dynamics Research Group
Environmental Science Division,
Institute of Environmental and Natural Sciences,
Lancaster University,
Lancaster, LA1 4YQ,

Phone: +44 (0)1524 593892
Fax: +44 (0)1524 593985
email: k.beven@lancaster.ac.uk
Homepage: Hydrology and Fluid Dynamics Research Group: http://www.es.lancs.ac.uk/hfdg/hfdg.html


Keith Beven


contents of the model
TOPMODEL predicts catchment water discharge and spatial soil water saturation pattern based on precipitation and evapotranspiration time series and topographic information. A minimum of four effective catchment parameters need to be estimated to characterize the discharge dynamics of the catchment. The parameters are fitted from the discharge predictions. Neither horizontal or vertical soil parameters need to be supplied. However, to estimate water table or soil moisture content from the saturation deficit requires soil information. A correct estimation of evaporation is critical for model performance. Evaporation is most frequently estimated by using the Penman-Monteith methods. For spruce ecosystems, Haude transpiration was successfully applie
principles of the model
Surface runoff is computed based on variable saturated areas, subsurface flow using a simple exponential function of water content in the saturated zone. Channel routing and infiltration excess overland flow are considered in the model. The structure of the model with regard to interception and root zone storage compartments is variable, allowing much flexibility to simulated different systems. Time steps should be in the range of an hour to represent surface runoff peaks. The length of the simulation period depends on the availability of precipitation and evapotranspiration input data. The spatial component requires a high quality DEM (digital elevation model) without sinks.

TOPMODEL is also integrated in GRASS GIS version 5
(see GRASS GIS Simulation Models: http://www.geog.uni-hannover.de/grass/modelintegration.html)

II. Technical Information

II.1 Executables:

Operating System(s): Lancaster University Freeware Topmodel Codes

TOPMODEL for Windows(includes help file, required Windows\System files and manual - put the grid.vbx, threed.vbx and vbrun300.dll files in your windows system directory)

Note: To load an initial example project file for the Slapton Woods Catchment then also download the following file: Slapton Calibration Example (please edit the calib.prj file once unzipped to reflect the local dir structure you are using)

TOPMODEL for Dos (includes manual and an initial set of input files)

II.2 Source-code:

Programming Language(s): FORTRAN :
TOPMODEL Fortran Source Codes

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

This is a list of model quantities sorted by their characteristics with hypertext links for more details.

III.2.2 Output

IV. References

Extensive bibliography of TOPMODEL

V. Further information in the World-Wide-Web

VI. Additional remarks

The empirical 'Haude factors' incorporate the phenology of the vegetation. ForAlaskan Tundra, a GASFLUX version was used. In Mediterranean oak systems, a linkage with GASFLUX is currently attempted. The output variable 'soil moisture' of the model is used in an other model as input variable. The model performance is independent of the spatial extend and resolution since only the distribution function of the topographic index is used internally allowing for a very computationally efficient simulation and extensive Monte-Carlo analysis of parameter combinations.

Additional information
Last review of this document by: J. Bierwirth Thu Sep 21 19:24:18 CEST 2000
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:51 CEST 2002

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