The Impact of Road Construction on Physical Land Degradation

Ethiopia provides a well-known example of a severely degraded African environment with consequent implications for food insecurity and famine. Physical land degradation after road building has been observed in Central Ethiopian highlands through gully erosion. In this research work by using a number of methods such as Field observation, gully measurement, GIS technique ,the 1997and 2006 topomap and socio-economic questionnaires, the impacts of the road on land degradation has been studied. It investigates how highway construction in the Ethiopian Highlands affects the gully erosion risk by quantifying the catchement area before and after road construction, the number of gullies created, and its characteristics in two selected cases: Addis Ababa-Fiche and Addis Ababa-Ambo. Accordingly; since the building of the road, 17 new gullies were created immediately downslope of the studied road segmensts and 8 other gullies at a radical change in its dimensions. The average catchement area is now 58.28 hectares and 74.52 on the road segments of Fiche and Ambo respectively, which is significantly different (p<0.001) from the average pre-road catchment area of 8.45 and 14.52 hectares