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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 15 (2007), Paper 27 Posted November 28, 2007 FACTORS THAT INFLUENCE THE FLOODING OF THE MIDDLE AND LOWER NTAMOGBA STREAM CATCHMENTS, PORT HARCOURT, NIGERIA
Gordon T. Amangabara1 2Institute of Geoscience and Space Technology, Rivers State University of Science and Technology, Port Harcourt, Nigeria ABSTRACT The Ntamogba stream is one of the principal drainage rivers of the city of Port Harcourt; draining and evacuating flood/storm water from the New GRA, the northeastern portion of Diobu, and the whole of the D/Line Areas. Due to urban sprawl and land mismanagement, this all important stream has lost its flood conveyance capacity, especially in the middle and lower reaches. The overflowing of its banks has become a severe threat to life and property in the watershed. Several efforts including the dredging of the channel have not abated the problem. This paper evaluates the pattern of development, disturbance intensity and the contribution of runoff to the stream by analyzing urban status maps of 1975 and 2004, as well as stream discharge of each of the sub basins. It is shown that 90% of the watershed in the middle and lower reaches has been built up thereby increasing the disturbance intensity. This results in rapid onset of peak runoff which the receiving channel can seldom accommodate, leading to overflowing of the stream’s banks. Reference: Amangabara, G.T., and A.E. Gobo. 2007. Factors that influence the flooding of the middle and lower Ntamogba stream catchments, Port Harcourt; Nigeria. Journal of Environmental Hydrology, Vol. 15, Paper 27. CONTACT: Gordon .T. Amangabara Institute of Pollution Studies (IPS) Rivers State University of Science and Technology PMB 5080 Port Harcourt. Nigeria E-mail: amangabara@yahoo.com |
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