Deep scour holes at tidal channels junctions, Bahía Blanca Estuary, Argentina

GINSBERG, SS; PERILLO, G.M.E.

Marine Geology

Elsevier

Lugar: Amsterdam; Año: 1999 vol. 160 p. 171 - 182

0025-3227

Deep-scour holes are common features at the junction of tidal channels in the Bah´ıa Blanca EstuaryArgentina., whereboth channels have similar morphodynamic characteristics. In order to study their possible origin and evolution pattern, thetwo largest known holes in the estuary were investigated. These holes are located in the Tres Brazas Channel and La ListaChannel, respectively, and have depths of 12–27 m2–17 m relative relief with respect to the channels’ bottoms.. Theirborders have a steep scour side3.58.at the mouth of each confluent channel and a gentle side1.58., corresponding to adepositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulationassociated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes isrelated to flood dominance acting on the steep sideinner face.and ebb dominance over the gentle outer. side. Holesmigrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rightsreserved.