Calibration using R-programming and parallel processing at the HUC12 subbasin scale in the Mid-Atlantic region: Development of national SWAT hydrologic calibration
Citation:
Bawa, A., K. Mendoza, R. Srinivasan, R. Parmar, D. Smith, K. Wolfe, J. Johnston, AND J. Corona. Calibration using R-programming and parallel processing at the HUC12 subbasin scale in the Mid-Atlantic region: Development of national SWAT hydrologic calibration. ENVIRONMENTAL MODELLING & SOFTWARE. Elsevier Science, New York, NY, 176:106019, (2024). https://doi.org/10.1016/j.envsoft.2024.106019
Impact/Purpose:
Soil And Water Assessment Tool (SWAT) is employed as the modeling engine of EPA funded Hydrologic and Water Quality System (HAWQS). Accuracy of modeling with SWAT requires accounting for local conditions. The most common way of accounting for local conditions is by calibrating SWAT using locally observed or monitored data. Majority of the modeling exercise involves model calibration which involves locating, accessing, storing, comprehending, and formatting local data as well as running calibration algorithms to estimate values of model input parameters. The calibration process requires the modelers to possess expertise in optimization techniques in addition to SWAT. Calibrating SWAT a priori would save modelers' time which they can spend on analyzing assessment data. Another benefit of calibrating SWAT at HUC12 scale for large parts of the country would be to bring consistency between assessment studies performed by various modelers.
Description:
The first phase of a national scale Soil and Water Assessment Tool (SWAT) model calibration effort at the HUC12 (Hydrologic Unit Code 12) watershed scale was demonstrated over the Mid-Atlantic Region (R02), consisting of 3036 HUC12 subbasins. An R-programming based tool was developed for streamflow calibration including parallel processing for SWAT-CUP (SWAT- Calibration and Uncertainty Programs) to streamline the computational burden of calibration. Successful calibration of streamflow for 415 gages (KGE ≥0.5, Kling-Gupta efficiency; PBIAS ≤15%, Percent Bias) out of 553 selected monitoring gages was achieved in this study, yielding calibration parameter values for 2106 HUC12 subbasins. Additionally, 67 more gages were calibrated with relaxed PBIAS criteria of 25%, yielding calibration parameter values for an additional 150 HUC12 subbasins. This first phase of calibration across R02 increases the reliability, uniformity, and replicability of SWAT-related hydrological studies. Moreover, the study presents a comprehensive approach for efficiently optimizing large-scale multi-site calibration.
URLs/Downloads:
DOI: Calibration using R-programming and parallel processing at the HUC12 subbasin scale in the Mid-Atlantic region: Development of national SWAT hydrologic calibration