User:Jcreer/SWB

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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" item the Project Explorer and select New Simulation | SWB.

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
  • Model Check
  • Export SWB
  • Launch SWB
  • Save, Export, and Launch SWB
  • Properties

Model Control

The parameters for the SWB model run are set in the Model Control dialog.

Required Inputs

  • Model Domain Definition
  • Growing Season
  • Climate Data
  • Flow Direction
  • Soil Group
  • Land Use
  • Available Soil-water Capacity
  • Initial Soil Moisture
  • Initial Snow Cover
  • Runoff Calculation and Routing Method
  • Evapotranspiration Method

Optional Inputs

  • Adjusted Water Capacity
  • Initial abstraction method
  • Specify iterative method tolerance
  • Ansi colored text
  • Frozen ground
    • Specify continuous frozen ground threshold values
    • Initial frozen ground index

Output Options

External Links