An investigation into the Adequacy of the Drainage system along Kampala-Jinja road.

Abstract

This dissertation presents results of the investigation of the adequacy of the drainage system along the Kampala- Jinja road from Wampeewo roundabout to Banda and proposed mitigation measures based on Road Design Manual Volume II: Drainage Design 2010, Kampala Drainage Master Plan 2016 T2 – Design Standards for Stormwater Facilities and The Manual for Hydraulic Design of Highway Culverts Third Edition. The drainage system is to prevent onsite water standing on the surface and convey the offsite storm runoff from one side of the roadway to the other. An efficient drainage system is therefore essential to allow water to flow off and away from the road as quickly as possible. Kampala-Jinja road drainage system is not properly functioning. The inadequacy of drainage system during the rainy season to pass the flood, poor quality construction, inappropriate site selection and improper alignment of some drainage structures with respect to the road alignment and disposal of solid waste into drainage structure are some of the reasons for poor performance of the system. The design peak discharge calculated for the different catchments along based on the return period of 25 years but verified using 50 years return period for that road section was big compared the discharge which is supposed to be drained by the already existing culverts hence flooding in that particular sections where culverts are located. Therefore, before the culverts are constructed, the design and the review data must be checked always during the design stage. It must be the design peak discharge to be greater than the review peak discharge to control the floods that over follow on the road. The drain suffered from low capacity, soil accumulation, the absence of inlets, lack of proper maintenance and disposal of solid waste into the drain and the crossing culverts. For these problems, it is suggested that it is important to perform checks for the designs before construction. The designer and contractor should follow the minimum requirement set by the Ministry of works and Transport regarding the drainage structure, size, length and alignments of road drainage structure so as to prevent the impact of poor drainage on the road pavement. Keywords: Adequacy, drainage system