ABSTRACT

Flooding has been an issue plaguing the Niger Delta region since time immemorial, the city of Asaba Delta State especially. It has been a hindrance to the urban development of the city and has caused for concern. In cases of extreme rainfall (that is high-intensity rainfall), the case study area Okpanam road becomes flooded even though the two-lane carriageway is flanked by drainage channels on both sides. 

The aim of this project is the assess the effectiveness of the existing drainage i.e. check the capacity of the drainage channel if adequate and if not, design a suitable channel to cater for extreme cases. Also different methods of improving the current drainage system in terms of quickly discharging water away from the pavement were discussed. 

For this project, a cases study area of Okpanam road was used. The method to be employed in this study involves using the method proposed by the Nigerian Highway Drainage Design Manual. Topographical data was gotten from goggle earth software, and photograph of the area was obtained and divided into subcatchments to enable computation of peak discharge. The hydrological data for the area was obtained and both hydrologic and hydraulic analysis were performed. For the hydrologic analysis, it involves estimating the peak discharge for specific return period. For the hydraulic analysis, the discharge capacity of the existing channel and was found to be adequate in case of extreme rainfall hence other methods of improving the drainage system were recommended.