User:Jcreer/SWB: Difference between revisions

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__NOINDEX__
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{{Version GMS 10.4}}
{{Future feature}}
The Soil-Water-Balance (SWB) model has been developed by USGS to allow estimates of potential recharge to be made quickly and easily.  
The Soil-Water-Balance (SWB) model has been developed by USGS to allow estimates of potential recharge to be made quickly and easily.  


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*Available soil-water capacity
*Available soil-water capacity
*Surface-water flow direction
*Surface-water flow direction
In addition to gridded land-surface data the model requires tabular daily climatological data (daily precip (inches), average air temperature [F], max air temp [F], min air temp [F]). Additional data may be required depending on model options: (1) daily average wind speed (m/s), (2) daily average relative humidity (%), (3) daily max relative humidity (%), (4) daily percentage of possible sunshine (%). Finally a lookup table must be supplied to assign curve numbers, interception values, rooting depths, and maximum daily recharge values.
In addition to gridded land-surface data the model requires tabular daily climatological data (daily precip (inches), average air temperature [F], max air temp [F], min air temp [F]). Additional data may be required depending on model options:
# daily average wind speed (m/s),  
# daily average relative humidity (%),  
# daily max relative humidity (%),  
# daily percentage of possible sunshine (%).  
Finally a lookup table must be supplied to assign curve numbers, interception values, rooting depths, and maximum daily recharge values.


==Creating an SWB Simulation==
==Creating an SWB Simulation==
To create an SWB simulation, do the following:
To create an SWB simulation, do the following:
# Right-click on the "[[File:Project Icon.svg|15 px]] Project" item the Project Explorer and select ''New Simulation'' | '''SWB'''.
# Right-click on the "[[File:Project Icon.svg|15 px]] Project" item the Project Explorer and select ''New Simulation'' | '''SWB'''.
A new "Simulation Data" [[File:Simulation Data Icon.svg|16 px]] item will appear in the Project Explorer, along with a "SWB Simulations" [[File:Simulation Folder Icon.svg|16 px]] item and a new simulation [[File:Simulation InactiveIcon.svg|16 px]] item. Right-clicking on the "SWB Simulations" [[File:Simulation Folder Icon.svg|16 px]] item also has a '''New Simulation''' command that allows adding additional SWB simulations to the project.


==Simulation Menu==
==Simulation Menu==
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* '''Save, Export, and Launch SWB''' – Combines several other commands together. First, it saves the project file, then exports files for the model run, and finally launches the SWB model run.  
* '''Save, Export, and Launch SWB''' – Combines several other commands together. First, it saves the project file, then exports files for the model run, and finally launches the SWB model run.  
* '''Properties''' – Opens the ''Properties'' dialog which displays the simulation properties and allows adding notes.
* '''Properties''' – Opens the ''Properties'' dialog which displays the simulation properties and allows adding notes.
 
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==Model Control==
==Model Control==
[[File:SWB ModelControl.png|thumb|340 px|Example of the SWB ''Model Control'' dialog]]
The parameters for the SWB model run are set in the ''Model Control'' dialog.
The parameters for the SWB model run are set in the ''Model Control'' dialog.
===Required Inputs===
===Required Inputs===
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**''End day'' &ndash; The ending time for the growing season.
**''End day'' &ndash; The ending time for the growing season.
**Hemisphere &ndash; Either the "Northern Hemisphere" or the " Southern Hemisphere" can be selected.
**Hemisphere &ndash; Either the "Northern Hemisphere" or the " Southern Hemisphere" can be selected.
*Climate Data
*''Climate Data'' &ndash; This section specifies the precipitation and temperature data.
**''Precipitation'' &ndash; Has options for entering a "Single station", "Arc grid", or "Surfer grid".
**''Precipitation'' &ndash; Has options for entering a "Single station", "Arc grid", or "Surfer grid".
***''File prefix'' &ndash; If using an "Arc grid" or "Surfer grid", the prefix for the precipitation files needs to be entered. Using the '''Select'' button will bring up a browser where the folder containing the precipitation files can be selected.
***''File prefix'' &ndash; If using an "Arc grid" or "Surfer grid", the prefix for the precipitation files needs to be entered. Using the '''Select'' button will bring up a browser where the folder containing the precipitation files can be selected.
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*''Available Soil-water Capacity'' &ndash; Expresssed in units of inches of water per foot of soil. Can be set to use either a "Raster" or "Shapefile". Clicking the '''Select''' button will bring up a ''Select Tree Item'' dialog to specify when raster or shapefile in the project to use for the available soil-water capacity. If a shapefile is used, the ''Shapefile field to convert to raster'' needs to specify which property in the shapefile to use.
*''Available Soil-water Capacity'' &ndash; Expresssed in units of inches of water per foot of soil. Can be set to use either a "Raster" or "Shapefile". Clicking the '''Select''' button will bring up a ''Select Tree Item'' dialog to specify when raster or shapefile in the project to use for the available soil-water capacity. If a shapefile is used, the ''Shapefile field to convert to raster'' needs to specify which property in the shapefile to use.
*''Initial Soil Moisture'' &ndash; Expressed as a percentage (0&ndash;100) of the available water capacity. Can be either a "Constant" value or a "Raster". If using a raster, clicking the '''Select''' button will bring up a ''Select Tree Item'' dialog to specify when raster in the project to use.
*''Initial Soil Moisture'' &ndash; Expressed as a percentage (0&ndash;100) of the available water capacity. Can be either a "Constant" value or a "Raster". If using a raster, clicking the '''Select''' button will bring up a ''Select Tree Item'' dialog to specify when raster in the project to use.
*''Initial Snow Cover'' &ndash;  
*''Initial Snow Cover'' &ndash; Expressed as water-equivalent value. Can be either a "Constant" value or a "Raster". If using a raster, clicking the '''Select''' button will bring up a ''Select Tree Item'' dialog to specify when raster in the project to use.
*Runoff Calculation and Routing Method
*''Runoff Calculation and Routing Method'' &ndash; Can be set to "Downhill", "Iterative", or "None".
*Evapotranspiration Method
**"Downhill" &ndash; This method sorts the grid cells to be either uphill or downhill.
**"Iterative" &ndash; In this method, water is iteratively moved across the entire grid until it has infiltrated or left the grid.
**"None" &ndash; Disables routing.
*''Evapotranspiration Method'' &ndash; Method to estimate potential evapotranspiration.
**"Thornthwaite-Mather" &ndash; Will produce lower estimates.
**"Jensen-Haise" &ndash; Requires values to be entered for ''Albedo'', ''Fraction of radiation on overcast days'', and ''Fraction of radiation on clear days''.
**"Blaney-Criddle"
**"Turc" &ndash; Requires values to be entered for ''Albedo'', ''Fraction of radiation on overcast days'', and ''Fraction of radiation on clear days''.
**"Hargreaves-Samani" &ndash; Suitable for use with gridded precipitation and air-temperature data.


===Optional Inputs===
===Optional Inputs===
*Adjusted Water Capacity
*''Adjusted Water Capacity'' &ndash; Calculates the adjusted water capacity independent of the model. Click the '''Select'' button for this will bring a ''Select Tree Item'' dialog where a raster can be selected to use for this value.
*Initial abstraction method
*''Initial abstraction method'' &ndash; Method for calculating the initial abstraction within the NRS curve number. Can be set to "TR-55", "Hawkins", or "Not Specified".
*Specify iterative method tolerance
*''Specify iterative method tolerance'' &ndash; Can be increased to improve convergence at a potential cost of also increasing mass-balance errors.
*Ansi colored text
*''Ansi colored text'' &ndash; Generates output with color coding for positive and negative values.
*Frozen ground
*''Frozen ground'' &ndash; This section sets options for continuous frozen ground.
**Specify continuous frozen ground threshold values
**''Specify continuous frozen ground threshold values'' &ndash; Defines boundary between completely frozen soil and completely unfrozen soil.
**Initial frozen ground index
*** ''Upper limit'' &ndash; Sets the upper boundary of the frozen ground threshold.
*** ''Lower limit'' &ndash; Sets the lower boundary of the frozen ground threshold.
**''Initial frozen ground index'' &ndash; Sets the initial continuous frozen ground index. Can be set to use a "Constant Value", "Raster", or "Not Specified".


===Output Options===
===Output Options===
* Suppress screen output
* ''Suppress screen output'' &ndash; Turns off the detailed mass-balanced information that is normally shown on the screen for each time step.
* Suppress daily files
* ''Suppress daily files'' &ndash; Prevents detailed mass-balance from being written to the recharge files.
* Suppress DISLIN messages
* ''Suppress DISLIN messages'' &ndash; Prevents the progress messages normally generated by the graphics library from being shown on the screen.
* Output grid file format
* ''Output grid file format'' &ndash; Allows the output file format to be changed. Can be "Not Specified", "Arc Grid", or "Surfer Grid".
*Output grid filename prefix
*''Output grid filename prefix'' &ndash; Allows changing the prefix that will be attached to the output files.
*Output grid filename suffix
*''Output grid filename suffix'' &ndash; Allows changing the suffix that will be attached to the output files.
*Output Variables
*''Output Variables'' &ndash; This table allows specifying specific variables for SWB to output as gridded data files.
**Variable name
**''Variable name'' &ndash; This column will allow selecting an SWB variable to output. Options include: rainfall, snow cover, snowfall, continuous frozen ground index, change in snow cover, snow melt, min. temperature, max. temperature, average temperature, interception, net precipitation, inflow, outflow, runoff inside, rejected recharge, net inflow, net infiltration, potential evapotranspiratio, actual evapotranspiration, precipitation minus potential evapostranspiration, soil moisture deficit, soil moisture surplus, accumulated potential water loss, soil moisture, and change in soil moisture.
**Daily output
**''Daily output'' &ndash; Writes output with daily values. Can be set to none, grid, plot, or both.
**Monthly output
**''Monthly output''  &ndash; Writes output with monthly values. Can be set to none, grid, plot, or both.
**Annual output
**''Annual output''  &ndash; Writes output with annual values. Can be set to none, grid, plot, or both.
**Copy/Paste Mode
**''Copy/Paste Mode'' &ndash; This option allows copying that values in the table into a spreadsheet or pasting values from a spreadsheet.
**Import
**'''Import''' &ndash; Opens a browser that allows importing a text or CSV file into the table.
**Export
**'''Export''' &ndash; Opens a browser to save out a text or CSV file contain the table values.
**Insert Above
**'''Insert Above''' &ndash; Adds a row in the table above the current selected row.
**Insert Below
**'''Insert Below''' &ndash; Adds a row in the table below the current selected row.
** Delete
** '''Delete''' &ndash; Removes the selected row from the table.
-->
==SWB Output Files==
After running the model, SWB will generate several output files.
*Recharge daily statistics &ndash; Contains the minimum, maximum, and mean values for all major components of the water balance for all grid cells in the model on a given day.
*Recharge daily report &ndash; Contains values representing the individual daily values summed over the entire model multiplied by the conversion factor.
*Recharge annual statistics &ndash; Contains mean values representing the annual sum of daily mean values.
*Log file &ndash; Contains a report of the processes performed during the model run.
*Grid and image files &ndash; Based on the selected optional output variables in the model control.


==External Links==
==External Links==
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{{Navbox GMS}}
{{Navbox GMS}}
[[Category:Numerical Models]]
[[Category:SWB]]

Latest revision as of 17:08, 4 January 2021

The Soil-Water-Balance (SWB) model has been developed by USGS to allow estimates of potential recharge to be made quickly and easily.

Required Input

Four gridded datasets are required:

  • Hydrologic soil group
  • land use/land cover
  • Available soil-water capacity
  • Surface-water flow direction

In addition to gridded land-surface data the model requires tabular daily climatological data (daily precip (inches), average air temperature [F], max air temp [F], min air temp [F]). Additional data may be required depending on model options:

  1. daily average wind speed (m/s),
  2. daily average relative humidity (%),
  3. daily max relative humidity (%),
  4. daily percentage of possible sunshine (%).

Finally a lookup table must be supplied to assign curve numbers, interception values, rooting depths, and maximum daily recharge values.

Creating an SWB Simulation

To create an SWB simulation, do the following:

  1. Right-click on the "Project Icon.svg Project" item the Project Explorer and select New Simulation | SWB.

A new "Simulation Data" Simulation Data Icon.svg item will appear in the Project Explorer, along with a "SWB Simulations" Simulation Folder Icon.svg item and a new simulation Simulation InactiveIcon.svg item. Right-clicking on the "SWB Simulations" Simulation Folder Icon.svg item also has a New Simulation command that allows adding additional SWB simulations to the project.

Simulation Menu

Right-clicking on the simulation item Simulation InactiveIcon.svg in the Project Explorer will bring up the following menu command:

  • Delete – Removes the simualation item.
  • Duplicate Creates a copy for the simulation, including all parameters set in the model control.
  • Rename – Allows changing the name of the simulation item.
  • Model Control – Opens the Model Control dialog where the model run parameters are set.
  • Model Check – Looks for potential errors in the model setup. Brings up the Model Checker dialog if issues are discovered.
  • Export SWB – Generates files used in the model run.
  • Launch SWB – Starts the SWB model run and opens the Simulation Run Queue dialog.
  • Save, Export, and Launch SWB – Combines several other commands together. First, it saves the project file, then exports files for the model run, and finally launches the SWB model run.
  • Properties – Opens the Properties dialog which displays the simulation properties and allows adding notes.

SWB Output Files

After running the model, SWB will generate several output files.

  • Recharge daily statistics – Contains the minimum, maximum, and mean values for all major components of the water balance for all grid cells in the model on a given day.
  • Recharge daily report – Contains values representing the individual daily values summed over the entire model multiplied by the conversion factor.
  • Recharge annual statistics – Contains mean values representing the annual sum of daily mean values.
  • Log file – Contains a report of the processes performed during the model run.
  • Grid and image files – Based on the selected optional output variables in the model control.

External Links