INFLUENCE OF ENGINEERING PROPERTIES OF SOILAND GROUNDWATER MOVEMENT ON GULLY DEVELOPMENT IN RAFINGORA, NORTHERN BIDA BASIN, NIGERIA

The formation and expansion of gullies in Rafingora community, northern sector the Bida Basin, Nigeria was investigated. This aimed at determining controlling factors for gully development area, using field parameter measurements, hydrogeological mapping geotechnical investigation soils from sites. U-shaped were mapped with sliding, slumping block fracturing as main modes propagation. Relief is gentle; slope angles range 1.58° to 1.96°, indicating little or no influence elevation on development. Gullies found be deeper than 3m, drainage area more 30m. Depth water open wells ranges 5.5m north-eastern part about 16.4m south-western part. side are mostly shallower table, contrary situation shows a direct relationship between table propagation further exacerbated by relatively high average hydraulic soils. have low plasticity, cohesion, angle internal friction (AIR) maximum dry density (MDD). A combination these poor properties makes friable crumbles easily when contact offers very resistance erosion. Conclusively, influenced bottom erosion due conductivity seepage forces, rather overland runoff. Reclamation attempts may consider lowering groundwater levels major strategy control area.