Continental-scale prediction of hydrologic signatures and processes

Hydrology and Earth System Sciences (HESS)
By: , and 

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Abstract

Understanding how dominant hydrologic processes and their drivers vary across diverse continental-scale landscapes is critical for hydrologic modeling and water management applications. Our research addresses this question by synthesizing large-sample watershed datasets, Caravan and GAGES-II, and developing random forest models to identify patterns in hydrologic function. We assessed dominant processes by examining hydrologic signatures – summary indicators of watershed function derived from hydroclimatic time series and random forest models across 14 146 gauged United States watersheds. The results reveal clear continental-scale gradients in hydrologic processes, including baseflow, overland flow, storage, and water balance losses. Our map of dominant processes highlights, for example, the transition from baseflow to fast responses and back to baseflow along the elevation gradient from the Appalachian spine, through the Piedmont, to the Eastern Coastal Plain; a distinct outer ring around the Great Lakes region; and sharp contrasts between coastal and inland processes in the West. Variable importance analysis from random forest models show that processes in the western U.S. are primarily controlled by climate, whereas in the eastern U.S., soil, geology, and topography play larger roles, with distinct human influences apparent in urban areas. Our approach of estimating dominant processes and their drivers facilitates extending process knowledge from research watersheds to the continental scale, assessing current hydrological understanding, and evaluating hydrological model structures.

Suggested Citation

Akari, R., Holt, A., Hammond, J., Husic, A., Coxon, G., and McMillan, H., 2026, Continental-scale prediction of hydrologic signatures and processes: Hydrology and Earth System Sciences (HESS), v. 30, p. 3647-3673, https://doi.org/10.5194/hess-30-3647-2026.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Continental-scale prediction of hydrologic signatures and processes
Series title Hydrology and Earth System Sciences (HESS)
DOI 10.5194/hess-30-3647-2026
Volume 30
Publication Date June 16, 2026
Year Published 2026
Language English
Publisher European Geosciences Union
Contributing office(s) Maryland-Delaware-District of Columbia Water Science Center
Description 27 p.
First page 3647
Last page 3673
Country United States
Other Geospatial conterminous United States
Additional publication details