Relationship between Soil Erodibility, Rainfall Erosivity and Geotechnical Parameters for Soils in Gully Erosion Sites in Urualla, Imo State, Nigeria

The purpose of this paper was to determine the geotechnical properties of soils in gully erosion sites in the study area and relate them to the soil erodibility factor for the area. Samples were collected from erosion sites. Values of liquid (LL) limits varied from 29.1 % to 38 % while plastic limits (PL) ranged from 14.0 % to 18.1 % and plasticity index (PI) went from 14.3 % to 18.2 % for the samples. These values are reflective of silty soils. Particle size analysis showed that fine sand /silt dominate the entire size population. The soils are not cohesive and have low shear strength. The soil erodibility factor, k for the area is greater than 0.4 which shows high erodibility. This factor also correlated with the silt/fine sand soil population. Results also show that the study area has high rainfall erosivity hence making it very susceptible to erosion. The study shows the need to relate geotechnical properties to soil erodibility investigations.