The dynamics of travertine dams

We present a simple, abstract model for travertine dam formation. The simulation uses a depth-averaged hydrodynamic code, coupled with an empirical precipitation model where surface-normal growth rate is proportional to local flow rate. The dynamics of the resulting formation, coarsening and migration (progradation) of crests is demonstrated and compared with field observations. The local self-enhancement of crests, due to increasing flow rate, in combination with lateral inhibition due to upstream drowning, implies a classical pattern formation system with a characteristic dam size, however this wavelength is not stable but increasing. The model also reproduces crest lobes, step bunching and other processes that contribute to the complex dynamics of travertine systems.