Morphological response of tidal basins to human interventions

This study focuses on the prediction of the long-term morphological evolution of tidal basins due to human interventions. New analytical results have been derived for an existing model [ASMITA, Aggregated Scale Morphological Interaction between a Tidal inlet and the Adjacent coast; Stive, M.J.F., Capobianco, M., Wang, Z.B., Ruol, P., Buijsman, M.C., 1998. Morphodynamics of a Tidal Lagoon and adjacent Coast. 8th International Biennial Conference on Physics of Estuaries and Coastal Seas, The Hague, September 1996, 397-407.]. Through linearisation of the model equations a set of time scales is obtained that describe the main features of the morphological evolution of tidal inlets. The magnitude of these system time scales is determined by inlet geometry and sediment exchange processes. The nature and degree of interventions determine which time scales are dominant. We focus on five different tidal inlets in the Wadden Sea. For these inlets, the system time scales have been estimated. The model has been applied to simulate the morphological response of the Marsdiep and Vlie inlets to the closure of the Zuiderzee in 1932. In this way, the model and associated system time scales for each of these inlets have been validated. Results show that in both inlets, the channels display the largest adaptation time. It will take at least a century before the channels and hence the tidal inlet systems reach a new morphological equilibrium. (C) 2004 Elsevier B.V. All rights reserved.