Abstract
The Colorado River Basin (CRB) is a crucial water supply source experiencing prolonged drought conditions. Hydrologic models of the CRB have historically relied on streamflow calibration alone, limiting confidence in their representation of spatially distributed hydrologic processes. Here, we implemented a calibration and multi-source evaluation framework for the Variable Infiltration Capacity (VIC) model using observations from ground snow stations, streamflow records, and NASA’s Soil Moisture Active Passive (SMAP) and Gravity Recovery and Climate Experiment (GRACE) missions. After model calibration with snow and streamflow records, VIC achieved an excellent streamflow performance at key sub-basin outlets in the CRB (e.g., Nash-Sutcliffe Efficiency of 0.96 in the Upper Basin). Independent evaluations with SMAP further revealed a strong model performance in reproducing surface (R2 = 0.71) and root-zone (R2 = 0.81) soil moisture, with systematic elevation-dependent patterns in the comparison. A multi-year evaluation with GRACE demonstrated a robust reproduction of basin-scale terrestrial water storage dynamics and their interannual variability (R2= 0.66–0.86). This multi-source evaluation framework establishes the VIC model capacity to represent subsurface water storage dynamics in different land cover types, providing enhanced confidence for supporting water management in the CRB.
Data availability
VIC and MetSim source codes are available on GitHub ( [https://github.com/UW‐Hydro/VIC](https:/github.com/UW‐Hydro/VIC) and [https://github.com/UW‐Hydro/MetSim](https:/github.com/UW‐Hydro/MetSim) , respectively). The historical meteorological forcing data are available from [https://prism.oregonstate.edu](https:/prism.oregonstate.edu) . Updated VIC parameters for the CRB and model outputs for the baseline CRB simulations conducted here are available through Zenodo ( [https://doi.org/10.5281/zenodo.17575686](https:/doi.org/10.5281/zenodo.17575686) and [https://zenodo.org/uploads/17576157](https:/zenodo.org/uploads/17576157) , respectively).
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Acknowledgements
This work was supported by the NASA Applied Sciences program (Award No. 80NSSC22K0925; “Managing the Colorado River as an Infrastructure Asset: Fusing Remote Sensing and Numerical Modeling in the Operations of the Central Arizona Project”). Additional support was provided by the Arizona Water Innovation Initiative (AWII), a multi‐year partnership with the State of Arizona led by Arizona State University’s Julie Ann Wrigley Global Futures Laboratory in collaboration with the Ira A. Fulton Schools of Engineering. We appreciate the conversations with staff members of the Central Arizona Project (CAP), including Vineetha Kartha, Nolie Templeton, Orestes Morfin, and Joshua Randall. The authors also acknowledge the use of Research Computing resources at Arizona State University and would like to thank their staff for their support.
Funding
This work was supported by the NASA Applied Sciences program (Award No. 80NSSC22K0925; “Managing the Colorado River as an Infrastructure Asset: Fusing Remote Sensing and Numerical Modeling in the Operations of the Central Arizona Project”). Additional support was provided by the Arizona Water Innovation Initiative (AWII), a multi‐year partnership with the State of Arizona led by Arizona State University’s Julie Ann Wrigley Global Futures Laboratory in collaboration with the Ira A. Fulton Schools of Engineering.
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Z.W. and E.R.V. conceived the ideas of the experiment. S.G. helped with data generation and organization. Z.W. generated the figures. Z.W. wrote the manuscript with important contributions from S.G. and E.R.V. All authors revised the manuscript text and made contributions to the development of the VIC application in the Colorado River Basin.
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Wang, Z., Ghimire, S., Whitney, K.M. et al. Revisiting the application of variable infiltration capacity (VIC) model in the Colorado River Basin using SMAP and GRACE. Sci Rep (2026). https://doi.org/10.1038/s41598-026-47430-9
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DOI: https://doi.org/10.1038/s41598-026-47430-9
