Myriem NOURI, doctorante
By 2050, 80% of the population will be an urbanized population that will request the expansion of urban territories to new areas, especially peri-urban areas. In Algeria, the population has grown (increased) from 11 million in 1961 to 41 million habitants in 2016 with a prediction of 54.5 million habitants in 2050. In a space territory exceeding two million km², its occupation is completely heterogeneous and it is characterised by a polarity in the north of the country. 1.9% of the territory which represent the coastal strip is occupied by 36.5% of the Algerian population [National office of statistics, RGPH 2008], which involves either a densification of the urban fabric or an urban expansion. These two phenomena are the cause of a high vulnerability to hazards due to internal population migration to the urban regions. In our case, floods, the first listed hazard by its direct impacts on the population, causing the largest losses and injuries recorded in Algeria (870 deaths during the exceptional event of November 2001 in Algiers). Therefore, the management of this risk in urban area is necessary.
At the first level, we compare different databases -major floods recorded in 100 years, daily precipitation in 40 rainfall stations and urban population movements in the Algerian territory- . It will helps us to define the causes of these floods (extreme rainfall event, urban runoff…). The second level of this study is to select expanding urban areas samples and propose urban solutions for a proper risk area management.
Our proposition consists to find solutions for sustainable demographic transition by looking for the problem at the sources.