Model:GSSHA

GSSHA

GSSHA Questionnaire

Contact Information

Model:	Gridded Surface/Subsurface Hydrologic Analyis (GSSHA)
Contact person:	Fred Ogden (Model developer)
Institute:	University of Wyoming
City:	Laramie, WY
Country:	USA
Email:	fogden@uwyo.edu
2nd person involved:	Charles Downer (Model developer)
3rd person involved:	Aaron Byrd (Technical contact)

Model description

Model type:

Modular model for the terrestrial domain.

Description:

Gridded Surface Subsurface Hydrologic Analysis (GSSHA) is a grid-based two-dimensional hydrologic model. Features include 2D overland flow, 1D stream flow, 1D infiltration, 2D groundwater, and full coupling between the groundwater, vadoze zone, streams, and overland flow. GSSHA can run in both single event and long-term modes. The fully coupled groundwater to surfacewater interaction allows GSSHA to model both Hortonian and Non-Hortonian basins. New features of version 2.0 include support for small lakes and detention basins, wetlands, improved sediment transport, and an improved stream flow model. GSSHA has been successfully used to predict soil moistures as well as runoff and flooding.

Technical information

Supported platforms:	Unix, Linux, Mac OS X, Windows
Programming language:	C++
Model development started at:	1988 and development still takes place
To what degree will the model become available:	Executable freely available. As teaching tool or for research/studies. Code access on a limited collaborative basis. Contact developers.
Current license type:	--
Memory requirements:	Depends on catchment
Typical run time:	depends on catchment size and process algorithms selected

Input / Output description

Input parameters:	DEM, land-use/land-cover, stream channels, precipitation, soils, aquifer maps. These index maps are used to classify catchment parameters related to overland/channel flow, soil/aquifer hydraulic properties, soil erodibility, contaminant loadings, etc. Model setup is greatly enhanced by the use of the US Dept. of Defense Watershed Modeling System (WMS), which serves as an interface between GSSHA and Arc/Info
Input format:	ASCII, Binary & US Dept. of Defense Watershed Modeling System (WMS)
Output parameters:	Flow rates, depths, soil moisture, sediment fluxes, erosion/deposition, contaminant/nutrient fluxes and concentrations, groundwater levels, reservoir storages.
Output format:	ASCII, Binary & US Dept. of Defense Watershed Modeling System (WMS)
Post-processing software (if needed):	yes, The US Dept. of Defense Watershed Modeling system can produce animations of model outputs. Run summary file includes detailed mass balance information. Output time series can be analyzed using spreadsheet or other software.
Visualization software (if needed):	Dept. of Defense, Watershed Modeling System (WMS)

Process description

Processes represented by model:	Rainfall: gage with nearest neighbor or inverse distance-squared weighting, radar. Interception: empirical model. Infiltration: Green & Ampt, Green & Ampt with redistribution, three-layer Green & Ampt, or Richard's equation. Overland runoff: 2-D finite volume diffusive wave with overland flow dykes and pothole lakes. Channel routing: 1-D dendritic finite-volume diffusive wave with culverts, on-channel lakes, rule curves, rating curves, scheduled releases. Groundwater: 2-D finite-difference with wells and various boundary conditions. Overland erosion: three alternative source equations, raindrop impact, erosion limits, deposition, arbitrary size classes. Channel sediment transport: advection-diffusion for fines, stream power for sands. Fate and transport of conservative and non-conservative constituents in soil, overland, and channels
Key physical parameters & equations:	Too much to describe in only 500 characters! See: http://www.gsshawiki.com/wiki/index.php5?title=Main_Page
Length scale & resolution constraints:	Dependent upon computational power and memory.
Time scale & resolution constraints:	Dependent upon computational power and memory.
Numerical limitations and issues :	Explicit finite volume routing formulations are time-step limited.

Testing

Available calibration data sets:	http://www.gsshawiki.com/wiki/index.php5?title=Main_Page
Available test data sets:	http://www.gsshawiki.com/wiki/index.php5?title=Main_Page
Ideal data for testing:	--

User groups

Currently or plans for collaborating with:

The development of GSSHA has been funded by the US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi. GSSHA is being actively used by a number of US Army Corps of Engineers districts.

Documentation

Key papers of the model:	Downer, C.W., and F.L. Ogden, 2006, Gridded Surface Subsurface Hydrologic Analysis (GSSHA) User's Manual, Version 1.43 for Watershed Modeling System 6.1, System Wide Water Resources Program, Coastal and Hydraulics Laboratory, U.S. Army Corps of Engineers, Engineer Research and Development Center, ERDC/CHL SR-06-1, 207 pp. Downer, C.W., and F.L. Ogden, 2004, Appropriate Vertical Discretization of Richard's Equation for Two-Dimensional Watershed-Scale Modelling, Hydrological Processes, 18:1-22. Downer, C.W., and F.L. Ogden, 2004, GSSHA: A model for simulating diverse streamflow generating processes, J. Hydrol. Engrg., 9(3):161-174. Downer, C.W., and F.L. Ogden, 2004, Prediction of runoff and soil moistures at the watershed scale: Effects of model complexity and parameter assignment, Water Resour. Res., 39(3), 10.1029/2002WR001439. Johnson, B.E., and T.K. Gerald, 2006, Development of nutrient submodules for use in the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) Distributed Watershed Model., J. Am. Water Resour. Assn., 42(6):1502-1525. Kalin, L. and M.H. Hantush, 2006, Comparative assessment of two distributed watershed models with application to a small watershed, Hydrol. Processes, 20(11):2285-2307. Levy, J.K., J.E.T. Moncur, and K. Takara, 2006, Introduction: Enhancing the capacity for sustainable watershed management, J. Am. Water Resour. Assn., pp. 1437-1439.
Is there a manual available:	yes
Model website if any:	http://chl.erdc.usace.army.mil/gssha

Additional comments

Comments:

Current version is 4.0