Abstract:
Poor drainage condition problem is one of the major challenges facing developing country.
Poor drainage causes early pavement distresses leading to structural failures of road as
pointed out by several researchers. In Jimma, new constructed roads were informed to fail
rapidly after opened to traffic. Bocho Bore Kebele is found in jimma town which are affected
by poor drainage condition.
The Objectives of this study are to assess the existing condition of drainage, cause of poor
drainage and to evaluate its effects on pavement. An exploratory and descriptive type of
methods was used to describe and explore the existing condition of drainage and pavement.
Data collection methods were carried out using both primary and secondary data sources, the
secondary data source was only relevant to support the primary data, which was
accomplished with the help of topographic map and design data. The collected data were
analyzed and presented using Microsoft-excel, tables, graphs, picture and percentages.
The result of this study, it was found that most roads in the kebele suffered from people
awareness, construction problem, absent of routine maintenance and poor management
system are causes for poor drainage condition. Based on respondent survey data, 80% had
responded for poor condition, about 16% of the respondents for fair and only 4% thinks the
drainage system is good. Result from cause of poor drainage condition occurred 69% due to
people awareness and absent of routine maintenance, 19% due to construction problem of
drainage structure, and 12% are due to cross slope difficult. This all problem lead to have low
drainage inlet efficacy, at station 1+400 1+900 (Tilahun Shell to Noc) the evaluation shows
that the efficiency of inlets is 40.36%. Due to surface water, debris and silt back to roadway,
pavement distresses occurred.
Based on the result I conclude that, poor drainage condition and its contributing to the early
deterioration of pavements, the existing drainage conditions inadequate to carry the flow.
Absent of routine maintenance, people awareness and poor management systems are also the
main cause for inlet not to work properly and failure of pavement.
This study recommends that to minimize early pavement failures, it is better to provide
adequate drainage system alert people to use efficient drainage, improve routine maintenance
ability and it helpful to increasing the service life of pavement
