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SPAW Hydrology and Water Budgeting

SPAW is a water budgeting tool for farm fields, ponds and inundated wetlands. The SPAW model performs daily hydrologic water budgeting using the SCS Runoff Curve Number method. The POND module incorporated within SPAW provides water budgeting modeling for small pond/reservoir/lagoon as well as a statistical analysis of pond inundation cycles based on the wetland growing season. POND simulations are performed based on SPAW water budget outputs from one or more fields.

Soil Water Characteristics is a program include with the SPAW installation. It is used to simulate soil water tension, conductivity and water holding capability based on the soil texture, with adjustments to account for gravel content, compaction, salinity, and organic matter. When using the given values it is important  to understand they are estimations and may not reflect the actual values for a given situation. Upper and lower limits of input values have been set to maintain the validity of calculations. Documentation for the model is found within the Help menu on the Soil-Water Characteristics Toolbar.

Copy the installation files to a temporary directory. Before installing upgrades, remove older versions using the SPAW Uninstall program (database files will be retained). After installation, the temporary directory and installation files can be deleted. 

SPAW and Soil Water Characteristics Programs (ARS download page)

SPAW climate files (web page with a climate file for each state)

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