Premium
Implementing a nonlinear groundwater module in the soil and water assessment tool (SWAT)
Author(s) -
Wang Y.,
Brubaker K.
Publication year - 2013
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.9893
Subject(s) - baseflow , groundwater , soil and water assessment tool , environmental science , hydrology (agriculture) , swat model , karst , macropore , groundwater flow , nonlinear system , streamflow , aquifer , soil science , geology , geotechnical engineering , drainage basin , geomorphology , geography , structural basin , paleontology , mesoporous material , biochemistry , chemistry , physics , cartography , quantum mechanics , catalysis
The Soil and Water Assessment Tool (SWAT) is widely used in modeling water quantity and quality. In the original SWAT, groundwater flow is calculated using a linear‐reservoir model, with outflow proportional to storage. However, observations show that this assumption is not always applicable; for example, macropores in Karst formations would seriously affect the groundwater behavior. A nonlinear groundwater algorithm was introduced in a new version of the SWAT model, called ISWAT. The Shenandoah Valley area in the Eastern U.S., which includes a number of geologic formations including Karst, was selected to test the modified ISWAT model. Parameter ESTimation (PEST) was coupled with ISWAT to auto‐calibrate the nonlinear parameter values. Ten years of record at 15 stream gauges were used to calibrate the model. The nonlinear ISWAT, statistically and visually, performed better in stream discharge estimation especially during baseflow recession and low‐flow periods. This indicated that the nonlinear algorithm can better represent groundwater behavior. The coupled ISWAT‐PEST approach can be used in future stream discharge simulation. Copyright © 2013 John Wiley & Sons, Ltd.