Tidal inlet morphodynamics through numerical prediction and measurements

Abstract

The formation of sandbars, spits and shoals are common at the inlet mouth particularly along coasts dominated by longshore sediment transport. These formations act as barriers, thus preventing the ingress of tidal flow. Sandbar and spit formation can be preferably averted by the construction of a pair of training walls, after which monitoring the behaviour of the stability of the tidal inlet is of prime importance. In cases where the tidal inlet meets a riverine estuary, the inlet dimensions and rate of littoral transport are primarily governed by the volume of water exchanged at the inlet mouth and the ebbing tidal currents, respectively. This paper discusses the case study of a micro-tidal inlet at Karaikal (10°54′52″N; 79°51′09″E), situated along the southeast coast of the Indian peninsula. This inlet coincides with the mouth of the Arasalar estuary, a tributary of the Cauvery river. A numerical model using the finite volume method is applied to estimate morphodynamic changes in the inlet channel driven by tide-induced currents and riverine discharge during the North-East monsoon season and the same has been validated through field measured data. The ultimate aim is to arrive at mitigation measures to combat siltation within the inlet.