The evolution of the coastaline of the Nador lagoon on the new pass between 1954 and 2003

Résumé

Historical studies of the shoreline are first used to determine the long-term trend of shoreline evolution. Originally used for a purely "theoretical" purpose, they have, since the end of the 1980s, become more and more practical applications, especially for the assessment of the impacts of coastal engineering works, the determination of the volumes of sand necessary for the artificial feeding of the beaches and the estimation of future changes of the shore line.

The dynamics of soft coasts are complex (Salomon, 2008) and are very often organized over areas several kilometers long. This technique of multi-date analysis of aerial photographs is one of the most used to observe coastal processes. The reliability of the results obtained (Crowel et al., 1991, Dolan et al, 1991) leads a large number of researchers to use these aerial photographs, whose examination allows a global and retrospective view of the phenomena.

The purpose of this study is to retrace the morphological evolution of the Marchica shoreline between 1954 and 2003 while: (i) identifying the trend of shoreline shifts; and (ii) assessing rates of erosion or erosion. increase by sector and by period. This will be confronted with the results produced by SOGREAH through GENESSIS which is a purely digital model. Our results will also be compared with the work done in the ACCMA project (2009).