Morphodynamic equilibria of double inlet systems

Abstract

Many tidal basins are connected to the open sea by multiple inlets. An example is the Guana-Tolomato-Matanzas (GTM) estuary (see Fig. 1), a 60 km long back-barrier estuarine system extending from Palm Valley to Palm Coast, Florida, US. A large area of this estuary ( 300 km2) is part of the GTM–National Estuarine Research Reserve with a great bio–diversity. This estuary is connected to the open sea by two inlets, the northern inlet is St. Augustine Inlet, located in St. Augustine, and the southern one, Matanzas inlet, is located 25 km southward. Hydrodynamics at the GTM estuary are primarily driven by the tidal propagation, although density driven flows might be relevant after major rainfall events (e.g. Sheng et al., 2008). Using parame- Figure 1. Guana–Tolomato–Matanzas estuary. ters characteristic for the GTM–estuary, the existence of morphodynamic equilibria of two–inlet systems is investigated using a width–averaged idealized morphodynamic model, and their sensitivity to parameters is assessed.