Abstract
It is very important to prevent the soil erosion which may occur on the uncovered slope after land reclamation.
In this paper, erosion phenomena are discussed with regard to topography, soil properties, snow melting and rainfall characteristics on the eroded slopes.
(1) Rill erosion on the surface occurs under the following three soil conditions:(a) Large hardness of the surface soil, (b) Small porosity, (c) Small saturated permeability.
The expansion of gullies is dependent on the following three soil conditions:(a) Small hardness of the surface soil, (b) Large porosity, (c) Large saturated permeability.
(2) The occurrence of gullies is dependent on the following three land slope conditions:(a) The steepness of slope over 15 in degrees, (b) The length of slope over 45 m, (c) The topography of natural down slope.
(3) The soil Properties and chamcteristics of slope at the occurrence limits of gullies intemct complexly, so that gully erosion, insitu, occurse xceeding or unreaching the limitting value thereof.Rather, the characteristics of slope rank soil conditions.
(4) Gullies which are caused by snow melting occurs certainly at the maximum snow melting velocity 9.2-9.6 mm/hr. However, the assumed lower limit will be the maximum snow melting velocity 6mm/hr.
(5) Gullies which are caused by rainfall will be surely formed by the precipitation of the total amounts over 26mm with the maximum rainfall intensities over 12mm/hr.
