Submarine shore-connected sand bank monitored by means of satellite images in the external zone of Bahía Blanca Estuary, Argentina

Abstract

The evolution of an extensive shore-connected sand bank bordering the Navigation Channel along an area larger than 10 km in the external zone of Bahía Blanca Estuary 15 years ago was indicative of a potential danger to the most important deep harbor system in Argentina. The analysis of bathymetric and side scan sonar surveys recently carried out indicates that this bank evolution occurred at a lower speed than what was expected. However, and as this potential danger to the only access channel to the harbor system still remains valid, the need to carry out frequent bank monitoring is imperative. Satellite images adequately processed and corresponding to different tidal stages, together with studies on tidal circulation in this area, show that during certain tidal stages, submarine banks located in the external zone of the estuary can be adequately visualized. Thus, satellite images become an important tool for bank monitoring on account of the fact that the qualitative analysis of the evolution of subtidal geomorphology can be done more regularly as well as at lower costs with respect to periodic bathymetric surveys.