ABSTRACT:

This data product is related to a journal article by Chuqiang Chen and Admin Husic entitled "Streamflow composition in U.S. rivers is shifting toward recent precipitation".

Abstract:
The fraction of streamflow derived from recent precipitation—termed ‘event water’—profoundly impacts water quality and flood risk. Here, we show that over the past four decades, this fraction has significantly increased in 27% of 754 U.S. catchments. We achieve this first continental-scale reconstruction by applying a deep learning model to a solute tracer dataset spanning nearly 24,000 storm events. Significant increases in event water fraction occur nearly twice as often as significant increases in streamflow, indicating that the composition of streamflow is often changing even where its magnitude is stationary. Using explainability methods, we identify intensifying precipitation and urbanization, together with the loss of forest cover, as the primary drivers. These results reveal a widespread shift towards the rapid conversion of precipitation to streamflow by watersheds, signaling a need to adapt water management strategies for a future of accelerating climate and land-use pressures.