Large-Scale Fine-Resolution Hydrological Modeling Using Parameter Regionalization in the Missouri River Basin

• Published in: Journal of the American Water Resources Association 2016-06, Vol.52 (3), p.648-666
• Main Authors: Daggupati, Prasad, Deb, Debjani, Srinivasan, Raghavan, Yeganantham, Dhanesh, Mehta, Vikram M., Rosenberg, Norman J.
• Format: Article
• Language: English
• Subjects: Agricultural production; Calibration; calibration and validation; Computer simulation; Corn; Creeks & streams; crop and water yields; Crop growth; Crop yield; Crops; Dynamics; fine-resolution modeling; Freshwater; Gauges; Groundwater; Hydrologic models; Hydrology; Interactions; large-scale modeling; Mathematical models; Modelling; Modulus of rupture in bending; regionalization; Regions; Resolution; River basins; Rivers; Soil; Soil water; Spatial calibration; Streams; Surface water; Surface-groundwater relations; SWAT; Watersheds
• ISSN: 1093-474X; 1752-1688
• DOI: 10.1111/1752-1688.12413

This study simulated crop and water yields in the Missouri River Basin (MRB; 1,371,000 km2), one of the largest river basins in the United States, using the Soil and Water Assessment Tool (SWAT) at a fine resolution of 12‐digit Hydrological Unit Codes (HUCs) using the regionalization calibration approach. Very few studies have simulated the entire MRB, and those that have developed were at a coarser resolution of 8‐digit HUCs and were minimally calibrated. The MRB was first divided into three subbasins and was further divided into eleven regions. A “head watershed” was selected in each region and was calibrated for crop and water yields. The parameters from the calibrated head watershed were extrapolated to other subwatersheds in the region to complete comprehensive spatial calibration. The simulated crop yields at the head watersheds were in close agreement with observed crop yields. Spatial validation of the aggregated crop yields resulted in reasonable predictions for all crops except dryland corn in a few regions. Simulated and observed water yields in head watersheds and also in the validation locations were in close agreement in naturalized streams and poor agreement in streams with high groundwater‐surface water interactions and/or reservoirs found upstream of the gauges. Overall, the SWAT model was able to reasonably capture the hydrological and crop growth dynamics occurring in the basin despite some limitations.