The Use of Level Contour Banks and Live or Dead Wash Stops in Erosion Control in Native Areas

Abstract

The setting out of terrace banks and channels on a variable grade for erosion control requires previous planning of terrace outlets and points of discharge for run-off water, planning which is done more satisfactorily on the basis of the minor or major watershed rather than for the individual holding. The setting out of the pegs for the terrace lines is not done very easily without the aid of an engineer's level in the hands of a skilled operator. In consideration of these two facts the decision is often made that in the native reserves, financial circumstances and absence of trained staff necessitate the adoption of simpler\methods. The methods must be such, it is said, as the natives can carry out themselves, or at least with a small amount of assistance by native instructors. It may be decided therefore that erosion control must be brought about by means of simply constructed contour banks, hedgeZ-Tines of grass or other live vegeta-,—ttori_or dead material such as lines of maize or sorghum stalks_ Provided the contour lines are set out accurately, and given that slope and soil are suitable under the rainfall intensities experienced, such methods may be effective, provided constant attention is paid to maintenance. There are, however, risks involved, which it is the purpose of this article to discuss.