GULLY HEAD RETREAT OF AWACH-KANO GULLIES, NYANZA PROVINCE, KENYA: FIELD MEASUREMENTS ANF PIXED-BASED UPALOPE CATCHMENT ASSESSMENT

Abstract

Gully erosion is a form of land degradation. Soil loss from croplands and residential areas and damage to human infrastructure caused by gully headcut retreat are particularly serious issues for developing countries in sub-Saharan Africa. We focused on the severe gully headcut retreat that incises agricultural land at the foot of the Kavirondo Rift escarpment in western Kenya. Between 2003 and 2004, measurements of the gully headcut retreat were taken. We investigated the topography, geology, and vegetation cover of the upslope catchment through field studies using remotely sensed imagery, analyzed using pixel-based data management. Analysis showed that factors sensitive to runoff were dominant and different overland flow paths caused different kinds of gully headcut retreat. Our pixel-based catchment assessment is a useful measure in the risk management of gully headcut retreat in this region.