Can Dominant Runoff Generation Mechanisms Be Disentangled Through Hypothesis Testing? Insights From Integrated Hydrological‐Hydrodynamic Modeling

Water Resources Research, Год журнала: 2025, Номер 61(4)

Опубликована: Апрель 1, 2025

Abstract Identifying flood‐inducing processes remains a challenge in catchment hydrology due to the complex runoff dynamics, particularly semi‐arid regions where surface and subsurface mechanisms alternatively drive streamflow across seasons. Tracer data can help identify hydrograph sources, but they are often unavailable or lack sufficient temporal resolution. To aid process identification at event‐scale, we developed an integrated hydrological‐hydrodynamic framework compared multiple model hypotheses informed by hydrological signatures. We systematically tested these through falsification, meta‐evaluation, spatial validation, posterior diagnostics, using Salsola nested southern Italy as case study. While all structures performed well on common calibration metrics, differences emerged transferability tests alternative diagnostic assessments. Some models, despite strong performance, exhibited inconsistent representations of internal mechanisms, indicating that achieved good results for wrong reasons. Furthermore, choice routing schemes significantly influenced high‐peak estimations overall when Horton‐type overland flow was considered. This underscores need treat methods key component event‐scale modeling. Our findings reveal during consecutive storm events study catchment, dominate initial stages, whereas become more influential later events, providing valuable insights may be applicable similar regions. Overall, emphasize importance hypothesis testing identification, which compensate absence hydrochemical separation. Additionally, our highlight value landscape‐based modeling approach distinguishing generation processes.

Язык: Английский

Exploration of coupled surface–subsurface hydrological model responses and challenges through catchment- and hillslope-scale examples

Frontiers in Water, Год журнала: 2025, Номер 7

Опубликована: Май 9, 2025

Selected runs with a physics-based model of surface water–groundwater interactions are used to examine in detail some numerical challenges and surprising behaviors that result from discretization, nested solution schemes, coupling, boundary condition, other factors. Regardless the spatial scale domain (field, hillslope, catchment, …), processes simulated by this class integrated models can exhibit widely varying dynamics within across different subsystems comprising land surface, unsaturated zone, deep groundwater formations. The presence heterogeneities, nonlinearities, complex conditions exacerbate difficulties resolving exchange fluxes lead unexpected or undesired results, including localized oscillations an upper bound on adaptive time stepping. need for accurate tracking surface–subsurface exchanges better control aspect ratio mesh distortion also influence constrain temporal discretization choices. Finally, performance assessments be highly sensitive response variables interest. We will illustrate these issues via test case simulations at large (13.66 km catchment transect) small (450 m 2 hillslope) scales, run scales 10 days hundreds years.

Язык: Английский