Melanie K. Vanderhoof Jay R. Christensen Heather E. Golden Charles R. Lane Adnan Rajib William Keenan Qianjin Zheng Arushi Khare Wayana Dolan 2026 <p><span id="_mce_caret" data-mce-bogus="1" data-mce-type="format-caret"><span>Quantifying and projecting the downstream benefits of water stored in lakes and wetlands (SW</span>_storage<span>) requires watershed hydrologic models, which often parameterize surface water storage in topographic depressions using static digital elevation model (DEM) data. Calibration and validation of modeled SW</span>_storage<span>&nbsp;dynamics using external data sets is uncommon, particularly across major river basins, with model calibration typically focused on observed discharge. Here, we develop and assess a novel remote sensing-based (RS) SW</span>_storage<span>&nbsp;data set (Sentinel-1 and Sentinel-2) for verifying simulated SW</span>_storage<span>&nbsp;estimates from a Soil and Water Assessment Tool (SWAT) model of the Upper Mississippi River Basin (UMRB; ∼440,000&nbsp;km</span>²<span>). Our results suggest that static DEM-based parameterization as well as model calibration based solely on discharge do not adequately capture spatial and temporal SW</span>_storage<span>&nbsp;dynamics in the UMRB. Mean SW</span>_storage<span>&nbsp;as estimated by SWAT was 74%&nbsp;±&nbsp;122% (mean&nbsp;±&nbsp;standard deviation) higher than RS SW</span>_storage<span>, where SW</span>_storage<span>&nbsp;in SWAT was underestimated in wetland-rich subbasins and overestimated in agricultural, tile-drained subbasins. Time series of SWAT SW</span>_storage<span>&nbsp;and RS SW</span>_storage<span>&nbsp;were positively correlated in only 38.8% of subbasins. As RS SW</span>_storage<span>&nbsp;is also vulnerable to error, storage estimates were compared to bathymetric data in select small wetlands. While uncertainty remains in the conversion from extent to storage for RS SW</span>_storage<span>, the method and data set presented here are a promising option for improved parameterization and calibration of SW</span>_storage<span>&nbsp;processes in SWAT and other process-based hydrologic models. Further consideration of these storage processes can potentially improve the accuracy of simulated streamflow in wetland-rich model domains.</span></span></p> application/pdf 10.1029/2025WR040206 en American Geophysical Union Remotely sensed surface water storage shows distinct patterns from SWAT-simulated data article