Time and spatial distribution of rainfall energy load in southeastern Nigeria

Abstract

Daily records of rainfall amount across a period of 7 to 15 years were collected from 8 stations with recording gauges in South-Eastern Nigeria. The stations were Calabar, Enugu, Ikom, Ogoja, Onitsha, Owerri, Port-Harcourt and Umuahia. The monthly and annual kinetic energy contents of these rains were computed using the energy equation of Kowal and Kassam (1977). The energy contents were then studied in terms of their distribution through the year and in the various locations. The time distribution of rainfall energy-load showed that energy load has similar distribution as rainfall amount over the year. Also, whereas all stations receive substantial amounts of rainfall energy-load in the months of May through October, greatest energy load concentration occurs in the months of July to September. The spatial energy load distribution showed that Southeastern Nigeria can be classified into two erosion risk levels - ‘Very high' erosion risk level and ‘High' erosion risk level. Calabar, Owerri, Port Harcourt, Umuahia and Ikom come under ‘Very High' erosion risk category, while Ogoja, Onitsha and Enugu fell under the ‘High' erosion risk category. It is expected that other locations in the region not covered in this study will fall under one or the other of the two categories.

Keywords: Rainfall; energy load; erosion; Nigeria

International Journal of Natural and Applied Sciences Vol. 2 (3) 2006: pp. 278-283