Soil and Water Assessment Tool (SWAT) Hydrologic/Water Quality Model: Extended Capability and Wider Adoption

Abstract

This article introduces a special collection of 16 research articles on new developments and applications of the Soil and Water Assessment Tool (SWAT) to address various environmental issues at a range of geographic and temporal scales. Highlights include addition of a subdaily erosion and sediment transport algorithm, a biozone module, and a new algorithm for shallow water table depth. Model applications include climate change impact assessments, model adaptation to regional environmental conditions, watershed-scale soil erosion assessments, and linkages to other models. A summary of reported model performance indicates that 85% of daily flow calibration statistics reported in this collection were satisfactory or better, with very good performance in four of the 20 calibration results and in three of the 19 validation results. Details of reported model parameters for calibration of flow and water quality constituents are provided for other SWAT modelers. This collection builds upon a previous ASABE 2010 SWAT Special Collection, demonstrating continued developments to enhance SWAT's capabilities and highlighting SWAT's continued expansion in international applications, especially in Asia.