Assessing the impact of flood on crop production in the Nabogo River basin, Ghana

The study examines the impact of floods on crop production in the Nabogo River basin, identifying flood risk and area affected. The flood extent in the research region was determined using Sentinel 1 images, global surface water, and a digital elevation model between July and October 2023. Flood analysis was carried out using Sentinel-2A and MODIS images, with cloud processing avoided and cloud and shadow masking techniques utilised. High-resolution data were used to map land use land cover (LULC) for affected and non-affected crops in the Nabogo River basin. The analyses were processed using Google Earth Engine. Heavy rainfall in the region, particularly upstream of the Nabogo River in northern of Ghana and Burkina Faso, causes severe flood damage every year, affecting farmers’ crop production and social economics through surface runoff and riverine damage. The flood extent inundates a minimum of 50 ha in July, extending to 34,090 ha in August. The flood extent reached its peak of 60,900 ha in September during discharge of water at the Burkina Faso’s Bagri Dam spillway through the White Volta in Ghana. Between July and October 2023, 24,223 ha of farm land were flooded, affecting 5,928 ha of crops. The impacted cropland experienced a 28-day flood with an average height of 1–3 m. Nevertheless, many farmers are forced to produce along the riverbank anyway due to land ownership and soil fertility benefits. To prevent ongoing losses, early-maturing crops are recommended.