Bay of Bejaia-Jijel extends over a length of 100 km with the presence of the ports, the beaches of rivers that
discharge of the bay. This area characterized by strong economic activity, namely tourism and fisheries.
However, severe erosion, high hydrodynamic activity and significant silting of ports affect this bay. Hence, the
interest of this study, which tries to explain these phenomena, based on multisource data with multitasking
models. First, we developed an algorithm that can convert satellite images in coastline vector. This technique
applied to three images LANDSAT TM and OLI sensed in 1987, 2011; 2015. The multi-temporal monitoring
coastlines show that the region suffered severe erosion. This erosion is 4.6 m / year for the period of 1987/2011
and 1.5 m / year for the period 2011/2015. To explain this phenomenon we interested to do a study of
hydrodynamics using the SWAN software. We used a long time series of wind speed and direction to discern
extreme cases in the region. For maximum wind, the significant wave height recorded very high values and a
very active orbital current with a speed that exceeds 0.7 m / s. Numerical modelling has allowed us to explain
the erosion but does not explain the speed difference coastline. To find the explanation of erosion speed
difference between the two periods we consulted the administrative archive of the region. In the archive, the
number of authorized hourglasses is, 12 in the 90s, but 36 quarries operate haphazardly. In this period the
balance of suspended matter is completely unbalanced which promotes erosion. After 2008, these quarries were
closed therefore the balance of the suspended material has improved and consequently coastal erosion has
decreased.
Journal Section | Research Articles |
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Authors | |
Publication Date | March 1, 2017 |
Published in Issue | Year 2017 Volume: 4 Issue: 1 |
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