Gully Control in SAT Watersheds

Gully erosion is geographically a widespread problem. It is common in the semi-arid region, characterized by denuded landscape and flash floods. An estimated 4 million ha of land in India and 29 million ha of land in Africa are affected by severe gully erosion. Gully erosion is more difficult and expensive to control than other types of soil erosion. A full understanding of erosion processes at various stages of gully development is essential to achieve gully stabilization. Without proper understanding often the measures taken for controlling gully were found unnecessary or ineffective. This report provides the basic knowledge of gully formation and its causes. The classification of gullies and the basic principles of its control are explained. Drawing primarily the experiences from the several on-farm watershed projects implemented by ICRISAT, the report provides the practical approach for gully control in the context of overall watershed development and management. The basic considerations and the design details of various gully control structures, viz., loose rock dam, double-row post-brush dam, double-row post-stone dam, single-row post-stone dam, stone wall dam, masonry check-dam, earthen check-dam and gabion structures are covered in detail. The key hydrological data, i.e., runoff volume and peak runoff rate measured at the watershed scale along with design peak runoff rate for the various locations in India are given. These data will greatly assist the watershed implementing agencies in the selection, design, construction and maintenance of gully control structure