Groundwater Recharge Modeling with SWAT

Session: 35. - Watershed Modeling across all Scales from Small to Large

Glenn O'Neil, Institute of Water Research - Michigan State University, [email protected]

Abstract

As part of larger project exploring potential climate change impacts on groundwater in southwest Michigan, the Soil and Water Assessment Tool (SWAT) was utilized to simulate groundwater recharge.  Twelve separate watersheds, ranging in size from 120 km² to 3,000 km², were modeled with SWAT to generate a groundwater recharge rate map of sufficient geographic scope so that rates could be fed into an existing groundwater model for the region.  Unlike most SWAT studies in which models are calibrated against total stream flow, sediment, and nutrient loads, this study calibrated each model against baseflow conditions to better simulate groundwater recharge over a relatively large geographic area.  A regression sensitivity analysis revealed that model variables describing the movement of water in the soil profile (ESCO, EPCO, GW_DELAY), surface runoff (CN2), and snow (SMTMP, SFTMP) had the largest impact groundwater recharge estimates.  Challenges explored in the production of the SWAT models included the delineation and representation of irrigation systems, aggregation thresholds for hydrologic response unit definition, and differences in calibration performance at various spatial and temporal scales.

1. Keyword
modeling

2. Keyword
watersheds

3. Keyword
GIS

4. Additional Keyword
groundwater