PNNL

Abstract

For almost 30 years, the Soil and Water Assessment Tool (SWAT) has been successfully implemented to various scientific subjects around the world. On the other hand, it has been reaching to the limit of potential flexibility in further development by the current structure. The new generation SWAT, dubbed SWAT+, was released lately with entirely new coding features. SWAT+ is designed to have far more advanced functions and capacities to handle challenging watershed modeling tasks for hydrologic and water quality processes. However, it is still inevitable to conduct model calibration before applying to engineering projects and research programs. In this study, the IPEAT+ was developed as an automatic calibration tool with SWAT+ with fours primary advantages: (i) open-source code to general users; (ii) complied and integrated directly with SWAT+ source code as a single executable; (iii) supported by the SWAT developer group; and, (iv) built with efficient optimization technique. The coupling work between IPEAT+ and SWAT+ is fairly simple, which can be conducted by users with minor efforts. IPEAT+ will be regularly updated with the latest SWAT+ revision. On the other hand, only few lines in the source code (IPEAT+ related codes only needed to be inserted without making any changes) are required to be updated if potential users would like to integrate IPEAT+ with various versions of SWAT+. IPEAT+ is the first automatic calibration tool integrated with SWAT+ source code. Users can take advantage of the tool to pursue more cutting-edge and forward-thinking scientific questions.