This seminar is part of the Tuesday Seminar Series organized by the Center for Hydrogeology and Geothermics (CHYN) at the University of Neuchâtel. We are pleased to welcome Céleste Romon from the Institut de Physique du Globe de Paris (IPGP), who will discuss groundwater flow, water table dynamics, and the formation of drainage networks.

Abstract
Groundwater emerges at the land surface in the form of springs and networks. Accordingly, the water table aligns with the topographic elevation along the course of a river. This observation, combined with the equations governing groundwater flow, allows us to reconstruct numerically the shape of the water table around a drainage network, and to predict river discharge. We first use this finding in a laboratory aquifer, in which we show that groundwater flow, through seepage erosion, is enough to initiate and grow a drainage network. In this controlled system, our numerical solution reproduces successfully the water table height measured by piezometers. We then upscale our approach to a semi-arid catchment in central India. Although constrained by a relatively sparse dataset, the numerical solution yields a realistic estimate of the water table shape and of the monsoonal river discharge, in agreement with field measurements.