Flood Dynamics in the Outskirts of Greater Lome (Togo)

This study analyzes flood dynamics in the Greater Lome area based on remote sensing and hydrometeorological data analysis. Daily rainfall data from the Lome-Airport synoptic station (2016 and 2020) were collected from the National Meteorological Agency of Togo (ANAMET) during the rainy season (March to October). Daily water levels in the Zio River at Togblekope were collected from the General Directorate of Hydraulics (DGH) during the rainy season (March to October) for the years 2016 and 2020. The time series were subjected to homogeneity tests to identify any artificial breaks in the data collected using RHtests dlyPrcp software. Radar data were processed using SNAP software, while maps were processed in ArcGIS 10.5. During 2016, a peak of 1,608 ha, corresponding to the maximum flooded area, was reached on August 24. At the start of the season, 40.29% of the maximum flooded area was submerged. In 2016, the population was therefore faced with at least thirty consecutive days of rising water levels. Not all districts were affected equally by the floods in 2016. The districts of Abobo, Djagble, and Be-Est were the most severely affected. The intra-annual dynamics of 2020 are similar to those of 2016. During 2020, the peak of 930 ha corresponding to the maximum flooded area was reached on September 2. At the beginning of the season, on June 16, only 11% of the maximum flooded area was submerged. All cantons were unevenly affected by the floods in 2020. The cantons of Abobo, Akepe, Mission Tove, Davie, and Adetikope were the most affected by the phenomenon. The results show a 45% decrease in flooded areas between 2016 and 2020, with a peak of 1,608 hectares reached on August 24, 2016, compared to 930 hectares on September 2, 2020, reflecting earlier and more intense flooding in 2016.