The Role of Snowmelt and Subsurface Heterogeneity in Headwater Hydrology of a Mountainous Catchment in Colorado: A Model‐Data Integration Approach

作者：Lijing Wang, Zexuan Xu, Chen Wang, Robin Thibaut, Craig Ulrich, Matthias Sprenger, Sebastian Uhlemann, Yuxin Wu, Evan King, Haruko Wainwright, Rosemary Carroll, Curtis Beutler, Kenneth H. Williams, Baptiste Dafflon · 发表于：Water Resources Research · 年份：2025 · DOI：10.1029/2025wr040651 · 被引用次数：2 · 研究领域：Hydrology and Watershed Management Studies、Groundwater flow and contamination studies、Hydrological Forecasting Using AI

Abstract Mountainous headwater streams are sustained by both snowmelt‐driven streamflow and groundwater discharge in the Upper Colorado River Basin. However, predicting headwater stream discharge magnitude and peak flow timing is challenging in mountainous terrains, where snowmelt rates vary with vegetation type and elevation, and heterogeneous subsurface physical properties influence groundwater storage and its release. We used a model‐data integration approach to investigate the roles of snowmelt and subsurface structure in stream discharge and groundwater level. We ran an ensemble of 100 integrated surface‐subsurface hydrologic models for a mountainous headwater catchment near Crested Butte, Colorado, USA. We also evaluated and calibrated these models against observed data sets, including snow depth measurements using distributed temperature probes, stream discharge, and groundwater levels. Calibration with multiple data sources using neural density estimators has further constrained uncertainty in subsurface properties and snowmelt rates. Results indicated that observed slower snowmelt rates in evergreen forests delayed the peak flow and baseflow onset. In upstream areas with lower subsurface permeability, water was stored within the subsurface but was not released as interflow or shallow groundwater flow, and thereby not contributing to downstream streamflow during recession limb periods. Double peaks in groundwater occurred in areas with spatial subsurface heterogeneity...