A Study of Erosion in the Mfuti Watershed for the Sanitation and Protection of the Zamba-Telecom Road in Kinshasa/DR Congo

Abstract

Zamba-Télécom is a road that has suffered erosion for a long time, more particularly gullying, due to poor drainage of runoff water and uncontrolled urbanization of the area in which it is located. We carried out a hydrological study throughout the watershed in which this road is located, in order to best size a canal attached to the road, which will effectively drain rainwater upstream. According to our calculations, to better manage this water, this road must be attached to a free surface canal, with a base of 1.3 m and a height of 1.4 m to thus evacuate a total peak flow of 7.462 m³/s to the Mfuti river. However, after carrying out a field trip, we sampled the soil from this basin and passed it to the laboratory. It turns out that the soil of the basin is mainly made up of fine sand, the grain size of which is 0.05 to 0.4 mm. For our different samples taken, the Atterberg limits gave the average value of the Plasticity Index: 8.8; the liquidity limit: 14.79 and a plasticity limit of 6, this watershed has solid, moderately plastic soil. Therefore, to protect the road from possible erosive phenomena, we should already limit urbanization in this area to limit runoff and instead encourage the infiltration of rainwater. We need to plant enough trees downstream of the watershed and develop best soil conservation practices.