WMS:GSSHA Channel Routing: Difference between revisions
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GSSHA is a two-dimensional finite difference rainfall/runoff model. A finite difference grid is used to establish the computational domain and parameters for surface runoff. The GSSHA model is fully coupled with hydraulic stream flow/routing models | Parameters for stream channels in [[WMS:GSSHA|GSSHA]] are defined using arcs and then mapped to the appropriate underlying grid cells. In order to define GSSHA channel parameters using arcs, the current coverage type must be set to "GSSHA". GSSHA is a two-dimensional finite difference rainfall/runoff model. A finite difference grid is used to establish the computational domain and parameters for surface runoff. The GSSHA model is fully coupled with hydraulic stream flow/routing models. | ||
==Smoothing Stream Cells== | ==Smoothing Stream Cells== | ||
Because elevation data used to define the surface runoff component of GSSHA does not contain the detailed resolution required to capture the actual stream bed elevation of the channels, the bed elevation profile can be highly irregular. These | Because elevation data used to define the surface runoff component of GSSHA does not contain the detailed resolution required to capture the actual stream bed elevation of the channels, the bed elevation profile can be highly irregular. These abrupt changes in elevation can cause instabilities in the channel routing computations, and therefore must be smoothed out. | ||
The '''Smooth Stream Arcs''' command is used to adjust the elevation of the stream bed for GSSHA | The '''Smooth Stream Arcs''' command is used to adjust the elevation of the stream bed for GSSHA: | ||
#Select a continuous set of arcs which represent the stream | |||
#Select ''GSSHA'' | '''Smooth Stream Arcs''' | |||
Initially the bed elevation is assigned the same value as the grid. Whenever a profile is shown, the bed elevation profile is displayed in blue while the grid elevation of the cell is shown in red. | Initially, the bed elevation is assigned the same value as the grid. Whenever a profile is shown, the bed elevation profile is displayed in blue while the grid elevation of the cell is shown in red. Make sure that no bed elevation is higher than the grid cell elevation. | ||
== Renumber Links | == Renumber Links and Nodes == | ||
In order to properly execute the channel routing routines of GSSHA, the stream channel must have the proper order and connectivity. This ordering or numbering can be done automatically | In order to properly execute the channel routing routines of GSSHA, the stream channel must have the proper order and connectivity. This ordering or numbering can be done automatically by selecting ''GSSHA'' | '''Renumber Links and Nodes'''. | ||
Links define whole channel segments and must be numbered | Links define whole channel segments and must therefore be numbered in ascending order from upstream to downstream. In other words, all channel segments must flow into downstream segments with a higher link number. | ||
== Related Topics == | == Related Topics == | ||
Revision as of 15:40, 15 April 2019
Parameters for stream channels in GSSHA are defined using arcs and then mapped to the appropriate underlying grid cells. In order to define GSSHA channel parameters using arcs, the current coverage type must be set to "GSSHA". GSSHA is a two-dimensional finite difference rainfall/runoff model. A finite difference grid is used to establish the computational domain and parameters for surface runoff. The GSSHA model is fully coupled with hydraulic stream flow/routing models.
Smoothing Stream Cells
Because elevation data used to define the surface runoff component of GSSHA does not contain the detailed resolution required to capture the actual stream bed elevation of the channels, the bed elevation profile can be highly irregular. These abrupt changes in elevation can cause instabilities in the channel routing computations, and therefore must be smoothed out.
The Smooth Stream Arcs command is used to adjust the elevation of the stream bed for GSSHA:
- Select a continuous set of arcs which represent the stream
- Select GSSHA | Smooth Stream Arcs
Initially, the bed elevation is assigned the same value as the grid. Whenever a profile is shown, the bed elevation profile is displayed in blue while the grid elevation of the cell is shown in red. Make sure that no bed elevation is higher than the grid cell elevation.
Renumber Links and Nodes
In order to properly execute the channel routing routines of GSSHA, the stream channel must have the proper order and connectivity. This ordering or numbering can be done automatically by selecting GSSHA | Renumber Links and Nodes.
Links define whole channel segments and must therefore be numbered in ascending order from upstream to downstream. In other words, all channel segments must flow into downstream segments with a higher link number.
Related Topics
GSSHA | |
|---|---|
| XMS Wiki Links | Calibration (Automated • Manual • Output) • Channel Routing • Contaminants • Digital Dams • Embankment Arcs • Feature Objects (Arcs • Nodes • Polygons) • File Types • Groundwater • Groups • Hydraulic Structures • Job Control • Join SSURGO Data • Mapping Tables • Maps • Menu • Model Linkage • Multiple Simulations • Nutrients • Observations • Output Control • Overland Soil Erosion • Pipe and Node Parameters • Precipitation • Radar Rainfall • Save GSSHA Project File • Smooth GSSHA Streams • Snowmelt • Solution (Analysis • Data) |
| Related Tools | MWBM Wizard • Using Soil Type Data with GSSHA |
| GSSHA Wiki External Links | GSSHA Wiki: Overview • Primer • User's Manual • Tutorials |
WMS – Watershed Modeling System | ||
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