WMS:GSSHA Overland Soil Erosion: Difference between revisions

From XMS Wiki
Jump to navigationJump to search
(rm related in template)
No edit summary
Line 1: Line 1:
Sediments in WMS are built around a similar concept as the [[WMS:GSSHA Contaminants|contaminants]]. Just like contaminants are individual processes to be modeled, so are sediments. Soil types are defined as having proportions of sediment types in them. To simulate sediments, the sediment option in the ''Job Control'' dialog must be turned on.
{{TOC right}}
The GSSHA ''Overland soil erosion'' dialog allows sediments to be defined. It is accessed by turning on ''Soil erosion'' in the other options section of the [[WMS:GSSHA Job Control|''GSSHA Job Control Parameters'' dialog]] and clicking the '''Edit parameter...'' button.  


Sediments are set up in three steps:
Sediments in WMS are built around a similar concept as the [[WMS:GSSHA Contaminants|contaminants]]. Just like contaminants are individual processes to be modeled, so are sediments. Soil types are defined as having proportions of sediment types in them.


# Create the sediment types,
The following buttons are at the bottom of the dialog:
# Create a soil type index map,
*'''Help''' – Opens this article in a web browser.
# Define sediment proportions and other relevant parameters for each soil type.
*'''OK''' – Saves all changes and closes the GSSHA ''Overland soil erosion'' dialog
*'''Cancel''' – Discards all changes and closes the GSSHA ''Overland soil erosion'' dialog


===Create the sediment types===
==Computation Methods==
[[File:Dialog GSSHA Overland Soil Erosion.png|thumb|right|500 px|GSSHA ''Overland soil erosion'' dialog.]]
The ''Computation methods'' section has the following options:
*''Transport capacity'' – A drop-down with the following options:
**"Engelund-Hansen" – This method calculates sediment transport for each sediment size class. The resulting total transport is calculated by multiplying the proportion of the size in the parent material by the calculated rate.
**"Kilinc-Richardson" – This method equation is used for estimating sheet and rill erosion from bare soils.
**"Unit Stream Power" &ndash; This method determines the product of the average flow velocity, ''U'', and the channel slope ''S<sub>o</sub>''.
**"Effective Stream Power" &ndash; This method measures the discharge that flows between lower and upper thresholds.
**"Slope and Unit Discharge" &ndash;
**"Shear Velocity" &ndash;
*''Adjust elevations'' &ndash; Turn on to tell WMS to write the ADJUST_ELEV card to the GSSHA project file. This tells GSSHA to change the elevation in the simulation based on erosion and deposition, and then export those elevations to a file.


First, a set of sediments must be created. The ''Sediments'' dialog is accessible from the ''GSSHA'' menu if sediments are turned on in the ''Job Control'' dialog, or it is accessible directly from the ''Job Control'' dialog. As the soil types will be defined in terms of portions of sediments, the set of sediments must contain all major sediment types in the simulation. For example, if the only soil type in the simulation is a silty clay, then two sediment types must be defined, namely silt and clay.  
==Sediments==
The ''Sediments section contains a spreadsheet where types of sediments can be defined. As the soil types will be defined in terms of portions of sediments, the set of sediments must contain all major sediment types in the simulation. For example, if the only soil type in the simulation is a silty clay, then two sediment types must be defined, namely silt and clay. Sediment types can be broken down into as fine or coarse of categories as desired.


Each sediment type has the physical properties of particle size and specific gravity, which are also specified in the ''Sediments'' dialog. Sediment types can be broken down into as fine or coarse of categories as desired. Selecting the '''Use Defaults''' button in the ''Sediments'' dialog will create four sediment types, a medium gravel, a medium sand, a medium silt, and a medium clay. The output filename parameter for each sediment type defines the name of the file that GSSHA will create showing the areas of deposition and scouring for each sediment type.
Creating sediment types offers a powerful means in GSSHA to simulate any sort of particulate transport, even solid contaminants such as lead or uranium. These are set up just as all other sediment types. Once they are set up, an overlay soil type coverage can be combined with the real soil type coverage to generate the contaminant distributions.


Creating the sediment types offers a powerful means in GSSHA to simulate any sort of particulate transport, even solid contaminants such as lead or uranium. These are as simply set up as all the other sediment types. Once they are set up, an overlay soil type coverage can be combined with the real soil type coverage to generate the contaminant distributions.
Below the spreadsheet are the following buttons:
*'''Add''' &ndash; Adds a new row to the sediments spreadsheet.
*'''Delete''' &ndash; Immediately deletes the selected row from the sediments spreadsheet.
*'''Use Defaults''' &ndash; Loads a set of four default sediment types into the sediments spreadsheet: medium gravel, medium sand, medium silt, and medium clay.


[[Image:Dialog_GSSHA_Overland_Soil_Erosion.png|thumb|none|left|500 px|GSSHA ''Overland Soil Erosion'' dialog]]
The spreadsheet has the following columns for defining the physical properties of particle size and specific gravity:
*''Description'' &ndash; Alphanumeric field. A descriptive name for the
*''Sp. Grv.'' &ndash; The specific gravity of the particles for this type of sediment.
*''Pt. Diam.'' &ndash; The average particle diameter, in millimeters, for this type of sediment.
*''Sorb Affinity'' &ndash;
*''Base Output Filename'' &ndash; Alphanumeric field. Underscores should be used instead of spaces. No special characters. Defines the name of the file that GSSHA will create showing the areas of deposition and scouring for each sediment type.
 
<!--
===Create a soil type index map===


The set of all sediments making up all the soil types for the simulation are defined in the sediments dialog. The '''Use Defaults''' button replaces the sediments already listed with the four types of sediments. For each sediment type, the particle specific gravity and average diameter must be given. An output file name must also be specified where GSSHA will write the results of the solution for that sediment type.  The computation method should be specified in the ''Overland Soil Erosion'' dialog and the ADJUST_ELEV card will be written to the GSSHA project file if the ''Adjust elevations'' option is turned on.  The ADJUST_ELEV card allows GSSHA to change the elevation in the model based on erosion and deposition and writes the adjusted elevations to a file.


===Create a soil type index map===


As with the contaminants, the next step in the process is to create the soil type index map. Creating this map is a fairly straightforward process. If no special sediment types are to be simulated, a soil type coverage imported from readily available files, such as those available from the EPA or the NRCS in the statsgo or ssurgo formats, is sufficient. Simply generate the [[WMS:GSSHA Maps|index map]] from the coverage. Later, the proportions of sediments for each soil type will be set up.
As with the contaminants, the next step in the process is to create the soil type index map. Creating this map is a fairly straightforward process. If no special sediment types are to be simulated, a soil type coverage imported from readily available files, such as those available from the EPA or the NRCS in the statsgo or ssurgo formats, is sufficient. Simply generate the [[WMS:GSSHA Maps|index map]] from the coverage. Later, the proportions of sediments for each soil type will be set up.
Line 28: Line 50:


In the ''GSSHA Index Map Table Editor'', select the soil erosion properties table and assign the correct index map. After generating the IDs from the map, assign the parameter values for soil erodability and dispersivity. Below these two parameters is a list of all of the sediment types, which were created in the ''Sediments'' dialog. To each sediment type assign the proportion of that sediment that makes up the soil type. For example, if the soil type is a silty clay, with 20% silt and 80% clay, a 0.2 should be assigned to the silt and a 0.8 the clay, with 0.0 assigned to the rest of the sediment types (if any). If a sediment type has not been created that should have been, simply return to the Sediments dialog and add the sediment type. Note that the sum of the sediment type proportions for each soil type needs to add up to 1.0 before GSSHA is run. If sediment types are added or deleted after setting up the soil type parameters the percentages will need to be checked.
In the ''GSSHA Index Map Table Editor'', select the soil erosion properties table and assign the correct index map. After generating the IDs from the map, assign the parameter values for soil erodability and dispersivity. Below these two parameters is a list of all of the sediment types, which were created in the ''Sediments'' dialog. To each sediment type assign the proportion of that sediment that makes up the soil type. For example, if the soil type is a silty clay, with 20% silt and 80% clay, a 0.2 should be assigned to the silt and a 0.8 the clay, with 0.0 assigned to the rest of the sediment types (if any). If a sediment type has not been created that should have been, simply return to the Sediments dialog and add the sediment type. Note that the sum of the sediment type proportions for each soil type needs to add up to 1.0 before GSSHA is run. If sediment types are added or deleted after setting up the soil type parameters the percentages will need to be checked.
 
-->


{{GSSHA Wiki}}
{{GSSHA Wiki}}

Revision as of 19:05, 17 May 2019


The GSSHA Overland soil erosion dialog allows sediments to be defined. It is accessed by turning on Soil erosion in the other options section of the GSSHA Job Control Parameters dialog and clicking the 'Edit parameter... button.

Sediments in WMS are built around a similar concept as the contaminants. Just like contaminants are individual processes to be modeled, so are sediments. Soil types are defined as having proportions of sediment types in them.

The following buttons are at the bottom of the dialog:

  • Help – Opens this article in a web browser.
  • OK – Saves all changes and closes the GSSHA Overland soil erosion dialog
  • Cancel – Discards all changes and closes the GSSHA Overland soil erosion dialog

Computation Methods

GSSHA Overland soil erosion dialog.

The Computation methods section has the following options:

  • Transport capacity – A drop-down with the following options:
    • "Engelund-Hansen" – This method calculates sediment transport for each sediment size class. The resulting total transport is calculated by multiplying the proportion of the size in the parent material by the calculated rate.
    • "Kilinc-Richardson" – This method equation is used for estimating sheet and rill erosion from bare soils.
    • "Unit Stream Power" – This method determines the product of the average flow velocity, U, and the channel slope So.
    • "Effective Stream Power" – This method measures the discharge that flows between lower and upper thresholds.
    • "Slope and Unit Discharge" –
    • "Shear Velocity" –
  • Adjust elevations – Turn on to tell WMS to write the ADJUST_ELEV card to the GSSHA project file. This tells GSSHA to change the elevation in the simulation based on erosion and deposition, and then export those elevations to a file.

Sediments

The Sediments section contains a spreadsheet where types of sediments can be defined. As the soil types will be defined in terms of portions of sediments, the set of sediments must contain all major sediment types in the simulation. For example, if the only soil type in the simulation is a silty clay, then two sediment types must be defined, namely silt and clay. Sediment types can be broken down into as fine or coarse of categories as desired.

Creating sediment types offers a powerful means in GSSHA to simulate any sort of particulate transport, even solid contaminants such as lead or uranium. These are set up just as all other sediment types. Once they are set up, an overlay soil type coverage can be combined with the real soil type coverage to generate the contaminant distributions.

Below the spreadsheet are the following buttons:

  • Add – Adds a new row to the sediments spreadsheet.
  • Delete – Immediately deletes the selected row from the sediments spreadsheet.
  • Use Defaults – Loads a set of four default sediment types into the sediments spreadsheet: medium gravel, medium sand, medium silt, and medium clay.

The spreadsheet has the following columns for defining the physical properties of particle size and specific gravity:

  • Description – Alphanumeric field. A descriptive name for the
  • Sp. Grv. – The specific gravity of the particles for this type of sediment.
  • Pt. Diam. – The average particle diameter, in millimeters, for this type of sediment.
  • Sorb Affinity –
  • Base Output Filename – Alphanumeric field. Underscores should be used instead of spaces. No special characters. Defines the name of the file that GSSHA will create showing the areas of deposition and scouring for each sediment type.


v • e
GSSHA
XMS Wiki LinksCalibration (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 ToolsMWBM Wizard  •  Using Soil Type Data with GSSHA
GSSHA Wiki External LinksGSSHA Wiki: Overview  •  Primer  •  User's Manual  •  Tutorials
v • e
WMS – Watershed Modeling System
Modules:Terrain Data  •   Drainage  •   Map  •   Hydrologic Modeling  •   River  •   GIS  •   2D Grid  •   2D ScatterWMS.PNG
Models:CE-QUAL-W2  •   GSSHA  •   HEC-1  •   HEC-HMS  •   HEC-RAS  •   HSPF  •   MODRAT  •   NSS  •   OC Hydrograph  •   OC Rational  •   Rational  •   River Tools  •   Storm Drain  •   SMPDBK  •   SWMM  •   TR-20  •   TR-55
Toolbars:Modules  •   Macros  •   Units   •   Digitize  •   Static Tools  •   Dynamic Tools  •   Drawing  •   Get Data Tools
Aquaveo
Retrieved from "https://www.xmswiki.com/index.php?title=WMS:GSSHA_Overland_Soil_Erosion&oldid=139921"