EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Erosional dynamics of a river driven by groundwater seepage

Marie Vulliet1, Eric Lajeunesse1, and Jerome A. Neufeld2
Marie Vulliet et al.
  • 1Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris
  • 2Centre for Environmental and Industrial Flows, Department of Earth Sciences, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK
Seepage erosion occurs when groundwater emerges at the surface of a granular heap. A
spring forms and feeds a river which entrains sediments, thus changing the groundwater
We reproduce this phenomenon in the laboratory using a quasi-2D aquifer filled with glass
beads, by imposing a water level at one end of the pile. Water flows through the aquifer and
emerges at the surface of the granular bed. For large enough water levels this river erodes
its bed and the spring progressively ascends the heap. We investigate its trajectory, the
evolution of the groundwater discharge and the river depth. Intriguingly, we find that after an
initial erosive period the river attains a new equilibrium profile, with an elevated spring.
We model the flow in the aquifer using Darcy's law, predicting the shape of the water table,
the position of the spring and the groundwater discharge. By applying Coulomb’s frictional
law to the forces experienced by a grain we predict a threshold for the onset of erosion as a
function of reservoir height and aquifer length. This prediction provides a dynamical theory
for the erosional dynamics of the river. Our combined theoretical and experimental approach
thereby helps constrain the response of an idealized erosive river-catchment system to
steady forcing.

How to cite: Vulliet, M., Lajeunesse, E., and Neufeld, J. A.: Erosional dynamics of a river driven by groundwater seepage, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3043,, 2022.