Flood determinants in equatorial coastal cities: case study of Douala (Cameroon)

Ndongo Barthelémy, Lako Stephane, Awe Tirmou Augustin

Tuesday 30 june 2015

12:57 - 13:00h at South America (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flood risk assessment, Poster pitches

Parallel session: Poster pitches: 5J. FloodRisk - Assessment

Coastal cities are usually prone to recurrent floods which slows down their social and economic development. Particularly in equatorial areas where heavy and long lasting rains are peculiar. Those rains usually cause floods which lead to damages to households who are most of the time low revenue. Adapting urban management and planning to this situation, provided that climate projections for Cameroon are announcing an increase in rainfall intensity and quantity, requires to identify the majors favourable to floods, and understand the flooding mechanism. This paper contributes to the understanding of the issue of coastal flooding through an analysis of the determinants that contribute to the occurrence of the phenomenon. From field surveying, some major factors have been identified and the hydrological characteristics of the area determined through hydrological analysis. These determinants are of hydro-meteorological, hydrodynamic and human order. The economic capital of Cameroon, Douala, was taken as a special case of coastal cities. It is characterized by heavy rainfall with high frequency, tide fluctuations, poor drainage system and also poor storm system handling. Indeed, beyond the physical constraints, Douala is distinguished by human practices favourable to the malfunctioning of drains. More-over, less considerations to climatic and social dynamics in the urban planning of the city is a major weakness. Then, to ensure sustainable development of coastal cities in general and Douala in particular, urban planning and management should take into consideration the climate and societal characteristics and variations that might influence urban flooding; as the damage costs are always higher than prevention measures.