Print Email Facebook Twitter Do intertidal flats ever reach equilibrium? Title Do intertidal flats ever reach equilibrium? Author Maan, D.C. van Prooijen, B.C. Wang, Z.B. de Vriend, H.J. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2015-11-30 Abstract Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the basic processes and feedback mechanisms underlying the long-term behavior of the intertidal system, restricting ourselves to unvegetated intertidal flats that are controlled by cross-shore tidal currents and wind waves and applying a 1-D cross-shore morphodynamic model. The results indicate that by an adjustment of the profile slope and shape, an initial imbalance between deposition and erosion is minimized within a few decades. What follows is a state of long-term seaward progradation or landward retreat of the intertidal flat, in which the cross-shore profile shape is largely maintained and the imbalance between deposition and erosion is not further reduced. These long-term trends can be explained by positive feedbacks from the morphology onto the hydrodynamic forces over the flat: initial accretion (erosion) decreases (increases) the shear stresses over the flat, which induces further accretion (erosion). This implies that a static equilibrium state cannot exist; the flat either builds out or retreats. The modeled behavior is in accordance with observations in the Yangtze Estuary. To treat these unbalanced systems with a one-dimensional numerical model, we propose a moving (Lagrangian) framework in which a stable cross-sectional shape and progradation speed can be derived for growing tidal flats, as a function of the wave climate and the sediment concentration in deeper water. To reference this document use: http://resolver.tudelft.nl/uuid:b34ba88d-842f-4691-85fb-b738ea107b65 Publisher American Geophysical Union (AGU) Embargo date 2016-05-30 ISSN 0148-0227 Source https://doi.org/10.1002/2014JF003311 Source Journal of Geophysical Research-Earth Surface, 120 (11), 2015 Part of collection Institutional Repository Document type journal article Rights © 2015 American Geophysical Union Files PDF 323435.pdf 1.94 MB Close viewer /islandora/object/uuid:b34ba88d-842f-4691-85fb-b738ea107b65/datastream/OBJ/view