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United States Department of Agriculture

Agricultural Research Service


Location: Hydrology and Remote Sensing Laboratory

Title: Overview and insights regarding the JEQ soil and water assessment tool (SWAT) special issue

item Gassman, P
item Sadeghi, Ali
item Srinivansan, R

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2013
Publication Date: 12/17/2013
Publication URL:
Citation: Gassman, P.W., Sadeghi, A.M., Srinivansan, R. 2013. Applications of the SWAT model special section: overview and insights. Journal of Environmental Quality. 43:1-8. DOI: 10.2134/jeq2013.11.0466.

Interpretive Summary: The goal of this lead-off article is to present a concise overview of the studies included in the SWAT special issue that will be published by the Journal of Environmental Quality (JEQ). It consisted of 21 papers presented in the 2011 International SWAT Conference in Toledo, Spain. The paper provides highlights of each study with an accent on innovative applications/adaptations of the model as well as key weaknesses/strengths revealed by some of the studies. Specifically, the objectives of this overview are to provide a brief history of SWAT development, a synthesis of calibration/validation results of the studies, and a summary of the overall SWAT verification results which is a fundamental aspect of the use of the SWAT model regardless of watershed size and conditions.

Technical Abstract: The Soil and Water Assessment Tool (SWAT) model has emerged as one of the most widely used water quality watershed- and river basin-scale models worldwide, and has been extensively applied for a broad range of hydrologic and/or environmental problems. Factors driving the international use of SWAT include extensive networking via dozens of training workshops and several international conferences held during the past decade, comprehensive on-line documentation and supporting software, and an open source code that can be adapted by model users for specific application needs. The catalyst for this special issue was 2011 International SWAT Conference & Workshops held in Toledo, Spain, which featured over 160 scientific presentations representing SWAT applications in 37 countries. This special issue presents 21 specific SWAT-related studies, most of which were presented at the 2011 SWAT Conference and which represent SWAT applications on five different continents, the majority of which were conducted in Europe and North America. Our objectives for this overview are to provide: (1) a brief history of SWAT development, (2) a synthesis the calibration/validation results of the special issue studies, (3) a synopsis of the results of each study by broad application categories, and (4) a summary of SWAT strengths and weaknesses including future research and development needs. Virtually all of the studies reported here have addressed some level of hydrologic verification and over half of the studies also describe verification of SWAT output for one or more environmental indicators. Other critical issues such as model calibration and validation approaches for large river basin systems, model testing constraints due to data limitations, the implications of projected climate change on stream health, movement of pollutants in northern European lowland watersheds, data input and routing method effects on sediment transport, development and testing of potential new model algorithms, description and testing of supporting software are presented, and future research needs are also discussed.

Last Modified: 06/23/2017
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