Saint Louis (Senegal) - Flood Hazard Map (ESA EO4SD-Urban)

For the urban and peri-urban area of St. Louis, three main flood scenarios have to be considered:
a. Fluvial floods (seasonal floods from the Senegal River) after heavy tropical rains in the upper part of the catchment area (mainly from August to November)
b. Floods triggered by rainfall stagnation after heavy local cloudbursts
c. Floods caused by sea-level rise, tidal waves and coastal erosion
Scenario a.) and b.) may occur at the same time.
The flood hazard map was generated based on the occurrence of flood events during the past 10 years.
The flood hazard classification in three qualitative hazard levels was done by summing up the flood occurences and reclassifying according to the following list:
Number of events Flood Hazard Level
1 1 (low)
2-3 2 (medium)
=4 3 (high)

The estimation of the area threatened by tidal waves and coast erosion is based on available reports and press releases as well as on the extrapolation of the mapped difference (done by visual interpretation) of the coastline between 2003 and 2019