IPEAT+: A built-in optimization and automatic calibration tool of SWAT+

Authors: YEN, HAW - Texas Agrilife Research; PARK, SEONGGYU - Texas Agrilife Research; Arnold, Jeffrey; SRINIVASAN, RAGHAVAN - Texas Agrilife Research; CHAWANDA, CELRAY - Vrije University; WANG, RUOYU - University Of California; FENG, QINGYU - Chinese Academy Of Sciences; WU, JINGWEN - Beijing Normal University; MIAO, CHIYUAN - Beijing Normal University; BIEGER, KATRIN - Texas Agrilife Research; DAGGUPATI, PRASAD - University Of Guelph; VAN GRIENSVEN, ANN - Vrije University; KALIN, LATIF - Auburn University; LEE, SANGCHUL - University Of Maryland; SHESHUKOV, ALEKSEY - Kansas State University; White, Michael; YUAN, YONGPING - Environmental Protection Agency (EPA); YEO, IN-YOUNG - University Of Newcastle; ZHANG, MINGHUA - Vrije University; ZHANG, XUESONG - Pacific Northwest National Laboratory

Submitted to: Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2019
Publication Date: 8/14/2019
Citation: Yen, H., Park, S., Arnold, J.G., Srinivasan, R., Chawanda, C.J., Wang, R., Feng, Q., Wu, J., Miao, C., Bieger, K., Daggupati, P., van Griensven, A., Kalin, L., Lee, S., Sheshukov, A.Y., White, M.J., Yuan, Y., Yeo, I., Zhang, M., Zhang, X. 2019. IPEAT+: A built-in optimization and automatic calibration tool of SWAT+. Water. 11(8):1681-1698. https://doi.org/10.3390/w11081681.
DOI: https://doi.org/10.3390/w11081681

Interpretive Summary: SWAT+ (Soil and Water Assessment Tool) is a river basin model used extensively around the world to determine the impact of land use and climate on water supply and water quality (sediment, nutrients, pesticides and pathogens). SWAT+ must be calibrated to measured stream flow and water quality to ensure realistic scenario analysis of land use and climate changes. IPEAT+ (Integrated Parameter Estimation and Uncertainty Analysis Tool Plus) was developed and linked to SWAT+ to perform calibration. The system has several advantages over the current system including: 1) open source, free and available to everyone, 2) the code is compiled and directly integrated, 3) the system is actively supported, and 4) contains a more efficient optimization technique. The new system will be easier for developers to maintain and support, easier for users to apply, and require less computer time.

Technical Abstract: For almost 30 years, the Soil and Water Assessment Tool (SWAT) has been successfully implemented to address issues around various scientific subjects in 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 recently 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 the SWAT+ model is applied to engineering projects and research programs. The primary goal of this study is to develop an open-source, easy-to-operate automatic calibration tool for SWAT+, dubbed IPEAT+ (Integrated Parameter Estimation and Uncertainty Analysis Tool Plus). There are four major advantages: (i) Open-source code to general users;(ii) compiled 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 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. If users would like to integrate IPEAT+ with various versions of SWAT+, only few lines in the SWAT+ source code are required to be updated. 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.