Geospatial information for sustainable food systems

A rapid geospatial assessment of flood impact in the West African countries of Niger, Burkina Faso and Chad

Record rainfall in this rainy season in 2020 has had an impact on West African countries. As of October 10, 2020, floods affected an estimated 2.1 million people in many regions of West and Central Africa. The impact in 2020 is particularly severe, and the number of people affected exceeds the totals of last year, when flooding affected 1.1 million people in 11 countries (OCHA, 2020).

These floods have caused the displacement of thousands of people, as well as the loss of food stocks, destruction of cultivated land and the death of many livestock. Losses in agricultural production expose an already vulnerable population to greater food insecurity and possibly malnutrition.

A rapid assessment of the impacts of floods for Chad, Burkina Faso and Niger was carried out by FAO in close collaboration with WFP with the aim of providing quantitative estimates of the impacts of floods and of household vulnerability in support of response and recovery and anticipation actions.

A first estimate, using flood data from NOAA VIIRS, for the period September 5 to 24, 2020, shows a total area flooded of 36,563 km2 (3.02 % of national territory) in Chad, 20,957 km2 (1.59%) in Mali, 10,016 km2 (2.13%) in Cameroon, 3.483 km2 (1.24%) in Burkina Faso, and 2.366 km2 (0.2%) in Niger.

Taking into consideration the specific location of the floods, a second integrated analysis with higher spatial resolution images, Sentinel 1 and 2, as well as NOAA VIIRS, SRTM, land cover (ESA GLC-2019), land cover data (OSS, 2015) and national statistics, has been produced. Since the data at the national level as well as the information needs were different, the analysis adapted to the different data available, and allowed the preparation of geospatial information adapted to the stated needs. This rapid, high-resolution image-based analysis provided information on the extent of floods, their severity and their impacts on croplands, and identified the most vulnerable populations at the local level.

State-of-the-art geospatial technologies with various remote sensing data have been of tremendous assistance in providing timely and adapted information on the impacts of a disaster and to help formulate recovery plans and anticipatory actions.