Data-guided exploration of streamflow generation mechanism: A global-scale analysis

Identifying a catchment’s streamflow generation mechanisms could inform the hydrologic functioning of the catchment, and how the catchment responds to the changes in climate and land-use. This study focuses on identifying the dominant streamflow generation mechanism and its drivers at more than 2,000 natural catchments located in North and South America, Europe, and Oceania. First, in a given catchment, we use a suite of diagnostic tools to infer the relative contribution of different streamflow generation mechanisms from precipitation and streamflow observations and simulated time series of subsurface storage. Then, in a large sample hydrology framework, we explore the major physical and climatic drivers of streamflow generation mechanisms. In this study, we made progress in differentiation among, seemingly similar, but naturally different subsurface mechanisms of streamflow generation (e.g., subsurface stormflow, transmissivity feedback, groundwater flow) as well as in identifying the drivers of these mechanisms. Our study extracts generalizable process understanding by combining conventional hydrologic science tools with modern data learning techniques.