ISGW—The Integrated Hydrologic Model Coupling HSPF and MODFLOW

When the surface water/groundwater interaction is important, applications of single-regime hydrologic models often lead to inaccurate simulations of hydrologic systems. By coupling the surface water model HSPF with the groundwater model MODFLOW, major limitations of each model can be overcome, allowing the user to conduct long-term simulations lasting decades with varying climatic and stress conditions. The integrated hydrologic model has been successful in simulating Florida's shallow water environment, even where there is significant interaction with deeper aquifers. The comparative strengths and weaknesses of single-regime and integrated hydrologic models are discussed. Results of case studies illustrate the advantages of the integrated hydrologic model, and how the results of the model can be used to help predict future impacts of groundwater production on wetland conditions in those areas where wetlands interact with the shallow groundwater environment.