Turning the tide: experimental creation of morphodynamic estuaries.

Maarten Kleinhans

Friday 3 july 2015

11:00 - 11:15h at Antarctica (level 0)

Themes: (T) Sediment management and morphodynamics, (ST) Morphodynamics of estuaries and coastal areas

Parallel session: 15A. Sediment - Coast

Large-scale equilibrium of estuaries and small-scale bar and channel morphodynamics are poorly understood. Morphodynamic models cannot yet reproduce the dynamic balance between cohesive bank formation (mud flats, marshes, riparian zones) and bank destruction. Furthermore many long-term models produce static morphology rather than the dynamic bar cycles, channel migration and ebb and flood channel interactions. We present pilot experiments in a novel experimental setup that produce these dynamic phenomena under entirely constant boundary conditions. We periodically tilted the entire flume to obtain and maintain similar tidal currents and sediment mobility in the flood and ebb phases. This contrasts classical methods where water level was periodically varied. Three sets of experiments together provide evidence that the method of tilting produces interesting morphodynamics: short tidal basins, estuaries and short reaches of estuaries with multiple channels and shoals.