SWAT model applications in hydrology: A systematic review

Abstract

The Soil and Water Assessment Tool (SWAT) has become an indispensable tool in hydrological modeling. It is widely applied for simulating streamflow, sediment transport, nutrient cycling, and agricultural processes within watersheds. This review provides a detailed analysis of SWAT's capabilities, theoretical framework, applications, strengths, limitations, and future research directions. We explore SWAT's structure, including its division of watersheds into hydrologic response units (HRUs) and the representation of key hydrological processes like evapotranspiration, infiltration, and routing. This paper delves into its applications in various fields, including water resource management, climate change impact assessment, and agricultural non-point source pollution modeling. The review critically examines SWAT's strengths, such as its user-friendly interface, physically-based approach, and vast user community. Discussion of limitations, including data requirements, computational intensiveness, and potential for regional bias. Finally, we explore emerging research directions for SWAT development, including integration with advanced climate models, improved representation of urban processes, and enhanced capabilities for real-time applications. This review aims to be a valuable resource for hydrologists, environmental scientists, and water resource managers seeking to understand and utilize the SWAT model for their research and decision-making needs.