Groundwater Modeling Under Variable Operating Conditions Using SWAT, MODFLOW and MT3DMS: a Catchment Scale Approach to Water Resources Management

This paper presents an integrated modeling approach by linking soil and water application tool (SWAT), modular finite difference groundwater flow (MODFLOW) and modular 3-dimensional multi-species transport (MT3DMS) models capable of predicting a groundwater system response, in terms of flow and salt concentrations, to current and future development conditions. SWAT, a semi-distributed hydrologic model, estimates the spatio-temporal distribution of groundwater recharge rates. These rates are then input to MODFLOW using an interface module developed that maps the HRU-based spatial resolution of SWAT outflows into the cell-based spatial structure of inputs to MODFLOW and MT3DMS. The integrated SWAT-MODFLOW-MT3DMS model is used in modeling Dehloran aquifer system located in the arid western region of Iran, experiencing changes in land-use, irrigation system and pumping locations and loads. The results illustrate the significance of the developed integrated modeling tool in quantifying the impact of changes in land and surface water resources on its subsurface water system.