ABSTRACT
This chapter utilizes a case example to show an issue in the conventional approach for provision of surface drainage system on slopes in mountainous regions. The issue is that the conventional approach has the potential to lead a large amount of unexpected surface runoff flowing down on man-made or natural slopes. The effect of surface runoff on slope stability is usually handled with the provision of surface drainage system on slopes. The slope drainage should collect runoff from both the slope and the catchment area upslope and lead it to convenient point of discharge beyond the limits of the slope. The design of the surface drainage system had a severe drawback that could cause the concentration of a large amount of water flow from the large hillside catchement to the catchpit D. The large amount of channeled water can cause major landslides with severe consequences.
