Short-Wave Effects on Mud Deposition at a Flat-Marsh Interface

PRATOLONGO, P.D.; PERILLO, G. M. E.; PICCOLO M. C.

Amelia Island, Florida, USA

Conferencia; AGU CHAPMAN CONFERENCE ON PHYSICS OF WAVE-MUD INTERACTION; 2008

American Geophysical Union

Although the Bahía Blanca Estuary (Argentina) is, in general, in an erosional stage, there are certain sectors in which depositional processes are occurring due to local hydrodynamic conditions. For instance, a number of Spartina marshes have developed since the major dredging of the 6D km navigational channel made in 19891990. The Villa del Mar tidal flat-rnarsh complex is regularly affected by short, locally generated waves due to the strong winds that commonly affect the estuary. Measurements of wave and tidal currents were made at the interface between the marsh and tidal flat with two ADV, eachlocated every environment, for a neap-spring tidal cycle. The ADV systems also allowedthe determination of the distance of the sensors to the sediment surface. Events of mud deposition and posterior erosion were detected after intensive wave activity, however, these depositions were concentrated only on the tidal flat and there were only minor changes on the marsh. Infact , it is clear from the analysis of the marsh, inclusive from data of SET, that sedimentation in this complex only occur at the tidal flat , whereas few sectors of the marsh are actually having sorne sedimentation in mud pocketsdepositional processes are occurring due tolocal hydrodynamic conditions. Forinstance, a number of Spartina marshes havedeveloped since the major dredging of the60 km navigational channel made in 19891990.The Villa del Mar tidal flat-marshcomplex is regularly affected by short,locally generated waves due to the strongwinds that commonly affect the estuary.Measurements of wave and tidal currentswere made at the interface between themarsh and tidal flat with two ADV, eachIocated every environment, for a neap-springtidal cycle. The AD V systems also allowedthe determination of the distance of thesensors to the sediment surface. Events ofmud deposition and posterior erosion weredetected after intensive wave activity,however, these depositions were concentrated only on the tidal flat and therewere only minor changes on the marsh. Infact, it is clear from the analysis of themarsh, inclusive from data of SET, thatsedimentation in this complex only occur atthe tidal fiat , whereas few sectors of themarsh are actuaJly having sornesedimentation in mud pockets.