ASSESSMENT OF BANK EROSION VARIABILITY IN RIYADH CATCHMENT, AKKO LOCAL GOVERNMENT AREA, GOMBE STATE, NIGERIA

Abstract

This study assessed how riverbank erosion varies across the Riyadh Catchment in Akko Local Government Area, Gombe State, Nigeria, and what factors are responsible for it. Both natural conditions and human activities were considered. Field data were collected from 19 cross-sections spaced about 300 meters apart along the river, while additional data came from satellite imagery, existing literature, and institutional sources. The analysis was carried out using QGIS and IBM SPSS. The findings show that over 90% of the catchment is underlain by the loose Keri-Keri Formation, making the riverbanks highly vulnerable to erosion. The area receives an average annual rainfall of about 800 mm. River discharge averages 5 m³/s but rises sharply to about 15 m³/s during the rainy season, increasing erosion intensity. Land use patterns reveal strong human influence: 57% of the land is urbanized, 27% is barren, 9% is farmland, 5% is covered by vegetation, and 2% consists of water bodies. Erosion rates vary along the river, with the lower reach experiencing the highest rate at 1.2 m/year, followed by the middle reach at 0.8 m/year, and the upper reach at 0.5 m/year. The river channel also becomes wider and deeper downstream. Overall, the study shows that erosion in the catchment is driven by a combination of fragile geology, seasonal increases in water flow, and intensive human activities, particularly urban expansion, highlighting the need for better land and watershed management.