Also known as Landlab OverlandFlow component
Model type Single
Model part of larger framework LandLab
Note on status model
Date note status model
Incorporated models or components:
Spatial dimensions 2D
Spatial extent Landscape-Scale, Reach-Scale, Watershed-Scale
Model domain Terrestrial, Hydrology
One-line model description Component simulating overland flow using a 2-D numerical approximation of the shallow-water equations following the de Almeida et al., 2012 algorithm for storage-cell inundation modeling.
Extended model description The Landlab OverlandFlow component is based on a simplified inertial approximation of the shallow water equations, following the solution of de Almeida et al. (2012). This explicit two-dimensional hydrodynamic algorithm simulates a flood wave across a model domain, where water discharge and flow depth are calculated at all locations within a structured (raster) grid. This component generates a hydrograph at all grid locations, and allows for flow to move in one of the four cardinal directions (D4) into/out of a given model node.
Name Jordan Adams
Type of contact Model developer
Institute / Organization University of Colorado
Postal address 1
Postal address 2
Town / City Boulder
Postal code 80301
State Colorado
Country United States
Email address

Supported platforms
Unix, Linux, Mac OS, Windows
Other platform
Programming language


Other program language
Code optimized Single Processor
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development 2012
Does model development still take place? No
If above answer is no, provide end year model development
Code development status Only maintenance
When did you indicate the 'code development status'? 2020
Model availability As code, As teaching tool
Source code availability
(Or provide future intension)
Through web repository
Source web address
Source csdms web address
Program license type BSD or MIT X11
Program license type other
Memory requirements variable
Typical run time variable

Describe input parameters This component operates on a Landlab RasterModelGrid instance, and requires that the user has downloaded and installed Landlab. Parameters listed below are required. Ones noted as (optional) will revert to the prescribed default values as described in the documentation.

Input parameters include:

grid : A Landlab RasterModelGrid, representing the topography h_init : (optional) Thickness of initial thin layer of water on the surface alpha : (optional) Time step coeffcient, described in Bates et al., 2010 and de Almeida et al., 2012. mannings_n : (optional) Manning's roughness coefficient. g : (optional) Acceleration due to gravity (m/s^2). theta : (optional) Weighting factor from de Almeida et al., 2012. rainfall_intensity : (optional) Rainfall intensity.

Input format ASCII
Other input format
Describe output parameters The Landlab OverlandFlow component outputs data as Landlab fields - numpy arrays containing data with the associated CSDMS standard name, listed below:

'surface_water__depth' : NumPy array of length nnodes. Water depths at a given time step. 'surface_water__discharge' : NumPy array of length nlinks. Water discharge values at a given time step. 'water_surface__gradient' : NumPy array of length nlinks. Water surface gradient at a given time step.

Output format
Other output format
Pre-processing software needed? No
Describe pre-processing software
Post-processing software needed? No
Describe post-processing software
Visualization software needed? No
If above answer is yes
Other visualization software

Describe processes represented by the model Routes a hydrograph (changing water discharges through time) across a gridded model terrain. At each location, water discharge is calculated at each time step as a function of surface roughness, local water depths and water surface slopes.
Describe key physical parameters and equations The key algorithms and parameters are described in length the Geoscientific Model Development paper by Adams et al., (2017).
Describe length scale and resolution constraints The model works best at watershed-scale domains, 100 km^2 and less have been tested. Of course, this is highly dependent on the grid resolution.
Describe time scale and resolution constraints The model works best for event to decadal time scales on a personal machine.
Describe any numerical limitations and issues

Describe available calibration data sets The model is tested against the known analytical solution (see Adams et al., 2017 for more details). It is unit-tested against this analytical solution every time Landlab is updated.
Upload calibration data sets if available:
Describe available test data sets
Upload test data sets if available:
Describe ideal data for testing

Do you have current or future plans for collaborating with other researchers?
Is there a manual available? Yes
Upload manual if available: Media:OverlandFlow Users Manual.pdf
Model website if any
Model forum / discussion board

This part will be filled out by CSDMS staff

OpenMI compliant Yes
BMI compliant Yes
WMT component Yes
PyMT component Yes
Is this a data component
Can be coupled with:
Model info
Nr. of publications: 1
Total citations: 32
h-index: 1
m-quotient: 0.14
Qrcode OverlandFlow.png
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Nr. of publications: 1
Total citations: 32
h-index: 1
m-quotient: 0.14

Featured publication(s)YearModel describedType of ReferenceCitations
Adams, Jordan M.; Gasparini, Nicole M.; Hobley, Daniel E. J.; Tucker, Gregory E.; Hutton, Eric W. H.; Nudurupati, Sai S.; Istanbulluoglu, Erkan; 2017. The Landlab v1.0 OverlandFlow component: a Python tool for computing shallow-water flow across watersheds. Geoscientific Model Development, 10, 1645–1663. 10.5194/gmd-10-1645-2017
(View/edit entry)
2017 Landlab

Model overview

See more publications of OverlandFlow



Input Files

Output Files