Remote Sensing-Based Flood Frequency Analysis in the Hadejia-Jama’are River Basin

The Hadejia-Jama'are River Basin in North West and North East Nigeria is both a critical wetland ecosystem and a frequently flooded landscape affecting multiple states. This study conducts a remote sensing-based flood frequency analysis to characterise the spatial extent and return periods of flooding across the basin. A 20-year archive of Sentinel-1 SAR imagery and MODIS Terra flood products are combined to generate annual maximum flood extents from 2004 to 2023. Statistical frequency analysis is applied to inundation area time series to derive flood extents corresponding to 5-year, 10-year, and 20-year return periods. Results indicate that the Hadejia floodplain and the Nguru Wetlands experience median annual inundation of 180,000 hectares, with the 20-year return period event covering approximately 310,000 hectares. Temporal trend analysis reveals a statistically significant increase in annual maximum flood extent over the study period, consistent with increasing upstream dam releases and changing rainfall patterns. The frequency maps support the Hadejia-Jama'are-Komadugu-Yobe Basin Authority in long-term floodplain management. Keywords: flood frequency, remote sensing, Hadejia-Jama'are, floodplain, SAR