This post is a historically grounded tribute to Pierre Perrault, the 17th‑century French savant whose work on the Seine basin laid the foundat...

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This post is a historically grounded tribute to Pierre Perrault, the 17th‑century French savant whose work on the Seine basin laid the foundat...
This post is a historically grounded tribute to Pierre Perrault, the 17th‑century French savant whose work on the Seine basin laid the foundations of quantitative hydrology. Framed as a question—“Do you know who performed the first quantitative rainfall–runoff estimates?”—it invites readers to connect a familiar concept in modern catchment hydrology back to the person who first demonstrated, with numbers, that rainfall alone can sustain river flow.

The article explains that Perrault systematically estimated rainfall over the Seine catchment, compared it with measured river discharge, and showed that even a fraction of annual precipitation was sufficient to account for the observed flow, overturning the then‑dominant belief that underground seas or mysterious sources fed rivers. By highlighting these experiments and his book De l’Origine des Fontaines, the post presents him as a founder of experimental hydrology who not only quantified the water balance but also anticipated the modern idea of a closed hydrologic cycle involving evaporation, transpiration, runoff, and springs.

Positioned within the HydroGeek newsletter’s broader focus on hydroinformatics and modern water science, the piece shows why remembering Perrault’s work still matters for today’s students and practitioners of rainfall–runoff modelling, flood analysis, and catchment water balance. It turns what might seem like a historical curiosity into an engaging reminder that many tools and concepts used in contemporary hydrology trace back to one of the earliest carefully measured rainfall–runoff studies on the Seine.

Click here to see the post : https://hydrogeek.substack.com/p/do-you-know-who-performed-the-first?r=c8bxy