Sediment transport in a tidal creek, Bahía Blanca Estuary, Argentina.

DEN HARTOG, L; OVERBEEK, B; RITZEN, M; PERILLO, GERARDO M. E.; PEREZ, DANIEL E

Mar del Plata

Congreso; Joint IAPSO-IABO Assemblies, 2001: An Ocean Odyssey; 2001

IAPSO-IABO

Bahía Blanca Estuary is in overall erosion, though areas are present where sedimentation prevails anddredging is necessary. At these areas, the water circulation and sediment transport characteristics haveto be studied in order to predict the location and necessity of dredging. Research has been carried out ina tidal creek located on a tidal flat along the Canal Principal, opposite to Puerto Galván. The mainobjective is to prove whether the creeks, or the tidal flat itself, contribute to the sedimentation to theCanal Principal. Data was gathered in March and April 2001 in the tidal creek along a tidal cyclewhenever the water depth allowed the use of the equipment in three stations located on a cross sectionof the channel covering both flanks and the center. Data consisted in current velocity using an acousticDoppler velocimeter, suspended sediment concentration using and OBS and salinity and temperatureinformation using a MiniCTD. Both the tidal flat and an adjacent part of the Canal Principal wascovered with a bathymetric. Suspended sediment transport on the tidal flat is in the direction to theCanal PrincipaL, with 0,8 g/s/m2. This implies erosion of the tidal flat and a transport of sediment inthe direction of the main channel. In the tidal creek, the sediment transport is in the direction from theCanal Principal towards the tidal flat with 68 g/s (for the cross section of the creek). However, thedifference may be due to the fact that part of the ebbing flow could not be sampled due to the lack ofenough depth to carry out the measurements.