Spatiotemporal Monitoring of Coastal Urbanization Dynamics: Case Study of Algiers' Bay, Algeria

During the last three decades, the Mediterranean coasts have been under strong anthropogenic pressure inducing ecological and biological degradations such as pollution, destruction of marine ecosystems, and loss of coastal dunes. In Algeria, the same findings have been observed in the bay of Algiers due to the massive urbanization as well as the absence of the quantitative analysis tools of this phenomenon. In this context, the assigned objective of this study is the monitoring of the urban growth in Algiers' bay between 1985 and 2015 and the prediction of the urban growth by 2030 using remote sensing data, cellular automata modeling, and the landscape metrics analysis. Concerning the prediction step, two scenarios are considered: the "tendencial" which presents the unmanaged urban growth of Algiers City and the active implementation of the Algiers Plan by 2029. To achieve this goal, a retrospective map representing land cover has been produced at different times; this later has allowed us to quantify the urban regions and to implement the urbanization growth model. On the other hand, this study has highlighted the contribution of the spatial metrics on multi-scale level (patch/core, class level and the landscape level) to monitor coastal urbanization in a geometric/fractal view through its multi-temporal evolution, as well as in the two predictive landscapes. This allowed through the spatial metrics indicator and predictive modeling to observe a tendency to massive urbanization of the bay at the expense of remaining natural areas, but also to provide and exhibit some geographical aspects such as the layout of urban cores and the linearity of urbanization parallel to the coast, in order to propose some significant measures for policy-makers to avoid the alarmist environmental degradation of the bay.