Evaluating the Stability of Gully Walls in Agulu-Nanka-Oko gully erosion complex area of Anambra State, Nigeria, using empirical approach

C. C. Osadebe¹, T. K. S. Abam², F. I. Obiora¹ and R. O. Sani¹

Research Article | Published January 2014

Advancement in Scientific and Engineering Research, Vol. 2(1), pp. 35-43

¹Nigerian Building and Road Research Institute, P.M.B. 1055, Ota, Ogun State, Nigeria.
²Institute of Geosciences, Rivers State University of Science and Technology, P.M.B. 5088,

Nkpolu, Port Harcourt, Rivers State, Nigeria.

*Corresponding author: E-mail: cosadebe1@yahoo.com.

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This paper describes the application of empirical model in evaluating the stability of gully wall profiles in parts of Anambra State. A theoretical model of gully wall profile, based on the principle of shear strength was used to determine the predicted gully wall profile of the Agulu-Nanka-Oko gully complex area. The coefficient of shearing resistance indicating the maximum sustainable inclination by the soil was obtained from the derived model. The process was repeated for each identifiable soil horizon to generate theoretical equilibrium profile for the gully wall. The theoretical profiles are compared with field observations of the gully wall geometry using linear regression. The coefficient of correlation (r) and coefficient of determination (R2) were then obtained. The results show that the observed profiles are consistently steeper (especially at the bottom) than the predicted profiles. This is probably due to undercutting of the bottom and toppling which is one of the causes of gully erosion. Furthermore, apparent cohesion can increase the soils shearing resistance, and hence results in steeper gully wall. The model validation test indicated that the model provided an effective tool for predicting gully walls profile.

Keywords: Gully, erosion, stability, empirical, model, profile.

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Citation: Osadebe CC, Abam TKS, Obiora FI, Sani RO (2014). Evaluating the Stability of Gully Walls in Agulu-Nanka-Oko gully erosion complex area of Anambra State, Nigeria, using empirical approach. Adv. Sci. Eng. Res. 2(1): 35-43
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