Estimation des superficies inondées par le fleuve Sénégal pour l'agriculture de décrue au Nord du Sénégal

Flood recession agriculture is vital for food security on Morphil Island in northern Senegal, relying on seasonal floods to fertilize the land. This practice remains the main socioeconomic activity, involving 80% of households, despite the presence of irrigation systems. Using Earth observation data from Google Earth Engine, this study mapped and analyzed the flooded areas on Morphil Island from 2000 to 2019. Sentinel-2 and Landsat-7 satellite imagery were used to detect surface water and quantify inundated areas. The wet season, from July to September, sees an average annual rainfall of 245 mm. Flooded areas vary significantly each year, with over 60,000 hectares flooded in high-water years and only 5,000 hectares in low-water years. Seasonally, flooding starts in early July (around July 19), peaks in September (around September 27), and recedes by early November (around November 5th or 6th). A 2018 map showed that arable lowlands, found mainly in large depressions and slightly elevated southern and riverbank areas, have elevations below 15 meters, as indicated by 30-meter resolution SRTM topographic data.