Letter abstract

Nature Geoscience 2, 193 - 196 (2009)
Published online: 1 February 2009 | doi:10.1038/ngeo432

Subject Category: Hydrology, hydrogeology and limnology

Growth laws for channel networks incised by groundwater flow

Daniel M. Abrams1, Alexander E. Lobkovsky1, Alexander P. Petroff1, Kyle M. Straub1,4, Brandon McElroy2, David C. Mohrig2, Arshad Kudrolli3 & Daniel H. Rothman1


The re-emergence of groundwater at the surface shapes the Earth's topography through a process known as seepage erosion1, 2, 3, 4, 5. In combination with flow over land6, seepage erosion contributes to the initiation and growth of channel networks1, 2, 3, 4, 5. Seepage processes have also been invoked in the formation of enigmatic amphitheatre-headed channel networks on both Earth7, 8, 9, 10, 11 and Mars12, 13, 14. However, the role of seepage in producing such channels remains controversial11, 15, 16. One proposed growth law for channel development suggests that the velocity at which channel heads advance is proportional to the flux of groundwater to the heads17. Here we use field observations and physical theory to show that this simple model, combined with a second linear response that relates channel branching to the total groundwater flux to the network, is sufficient to characterize key aspects of the growth and form of a kilometre-scale seepage-driven channel network in Florida18. We find that the dynamics for the advance of channel heads are reversible, which allows us to estimate the age of the channel network and reconstruct the history of its growth. Our theory also predicts the evolution of the characteristic length scale between channels19, thereby linking network growth dynamics to geometric form.

  1. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
  2. Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712, USA
  3. Department of Physics, Clark University, Worcester, Massachusetts 01610, USA
  4. Present address: Department of Earth and Environmental Sciences, Tulane University, New Orleans, Louisiana 70118 USA

Correspondence to: Daniel H. Rothman1 e-mail: dhr@mit.edu


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