© Science and Education Publishing DOI:10.12691/aees-3-2-5 The Mechanics of Civil –Works Induced Gully Erosion: Applications to Development of Preventive Measures in

Abstract Evidence from a comparative analysis of shear strength of surficial sediments and shear stress of runoff for various flow depths and natural slopes in parts of South- Eastern Nigeria indicate that these sediments are really not as highly erodible as it is presently believed. The shear strength of top soils range from 5 to 60kN/m2, and are higher than shear stress of runoff which ranges from 0.07 kN/m2 to 14 kN/m2 for flow depths of up to 5cm and slope angles of about 200 both of which rarely occur in nature. Soil erosion should not constitute a major problem in this region. The problem of soil erosion in our environment is primarily due to the reckless removal of top soil and activities that tend to concentrate runoff. It is thus necessarily due to high erodibleness of soils, but rather as a result of our unwillingness to help these soils sustain our development. It is shown that implementation of simple and cost effective designs in our roads layout, and other related civil engineering works can considerably reduce soil erosion problems in the area. The efficacy of the technique to curb the incidence of erosion is examined within the context of hydrological and runoff- water routing functions of the design components. Implementation of these techniques will not only minimize environmental hazards and keep erosion in near total check, but will also add an aestheti