Effects of runoff on the road infrastructure; A case study of the Kampala-Hoima, Northern-by-pass and Sentema roads in Rubaga Division

Abstract

Runoff and storm water management problems are on the rise as the rate of urbanization increases along with the increasing extreme precipitation patterns. The study area experiences increased impervious surfaces due to urban soil disturbance and construction activities, leading to reduced infiltration rates and high volumes of runoff. The problem faced is evidenced through channel bed and bank erosion, siltation and channel blockage which changes the shapes and sizes of the channels and the roads. The overall objective was to assess the effects of runoff on the road infrastructure. GIS maps were generated to illustrate the Digital Elevation Model, Slope, runoff flow direction, and flow accumulation. The slope variation influenced the flow velocity and erosive force of the runoff, causing sediment detachment, transport, and deposition downstream. Runoff was quantified using rainfall datasets, land use/land cover data of Five (5) years, and soil data for my study area to analyze the trend over the years. The effects of runoff were captured through GPS coordinates and questionnaires administered to roadside business operators and residents. Hotspot mapping indicated that Sentema road was affected most with the highest points, 34 for Channel bank erosion, 16 for channel bed erosion, 11 for siltation and only 2 for channel blockage. The Northern-by-pass was affected most (42 points) by massive siltation with vegetation. Kampala-Hoima roads was averagely affected with 21, 5, 22 and 7 points captured for bank erosion, bed erosion, siltation and blockages respectively. The findings also revealed concerns about road maintenance and the safety of road users, particularly due to erosion along channel banks.