Nwachukwu MA, Alozie CP and Alozie GA
Hardships, economic wastes, and loss of lives due to yearly Owerri urban flooding pose a challenge to environmentalists. In this study, environmental field investigation, analysis of drainage and reliable rainfall data (2006-2013) were carried out. Drainage blocked with refuse, buildings obstructing natural drainage, increasing urban cementation and the low topographic landscape of Owerri urban were observed as major causes of the flooding. A flood risk map showed Owerri urban as vulnerable. Analysis of rainfall intensity (RI) revealed a tradition of one year drop after two years of rising. Change in RI from the one year of the drop to the two years of the rise was observed in a fairly decreasing order (41%-23%). Hyetographs showed the highest peak of RI in July 2006 measuring 595.l mm/ hr. and lowest in May 2013 with 330.7 mm/hr. with a 3-phase drainage network channeling runoff to Nworie River, flooding in Owerri urban will come to an end. The law allowing ≤ 70% of impervious surface per developed plot of land should be enacted and be enforced to support natural infiltration.
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