Deep-scour holes at tidal channel junctions, Bahia Blanca Estuary, Argentina

SILVIA SUSANA GINSBERG; GERARDO PERILLO

MARINE GEOLOGY

ELSEVIER SCIENCE BV

Año: 1999 vol. 160 p. 171 - 182

0025-3227

Deep-scour holes are common features at the junction of tidal channels in the Bah´ýa Blanca Estuary Argentina., where both channels have similar morphodynamic characteristics. In order to study their possible origin and evolution pattern, the two largest known holes in the estuary were investigated. These holes are located in the Tres Brazas Channel and La Lista Channel, respectively, and have depths of 12–27 m 2–17 m relative relief with respect to the channels’ bottoms.. Their borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved both channels have similar morphodynamic characteristics. In order to study their possible origin and evolution pattern, the two largest known holes in the estuary were investigated. These holes are located in the Tres Brazas Channel and La Lista Channel, respectively, and have depths of 12–27 m 2–17 m relative relief with respect to the channels’ bottoms.. Their borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved ´ýa Blanca Estuary Argentina., where both channels have similar morphodynamic characteristics. In order to study their possible origin and evolution pattern, the two largest known holes in the estuary were investigated. These holes are located in the Tres Brazas Channel and La Lista Channel, respectively, and have depths of 12–27 m 2–17 m relative relief with respect to the channels’ bottoms.. Their borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved 2–17 m relative relief with respect to the channels’ bottoms.. Their borders have a steep scour side 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved 3.58. at the mouth of each confluent channel and a gentle side 1.58., corresponding to a depositional zone at the opposite downstream side. Geomorphologic characteristics, the nature of the tidal circulation associated to the Tres Brazas Channel, and estimates of the net sediment transport suggest that the evolution of the holes is related to flood dominance acting on the steep side inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved inner face. and ebb dominance over the gentle outer. side. Holes migrate headward in a pattern opposite to similar holes formed in fluvial reaches. q1999 Elsevier Science B.V. All rights reserved reserved q1999 Elsevier Science B.V. All rights reserved