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