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Regional Flood Frequency Analysis of Catchments in Upper Benue River Basin Using Index Flood Procedure


OC Izinyon
HN Ajumka

Abstract

Regional flood frequency analysis was conducted for catchments within Upper Benue river basin in Nigeria using the Index flood (IF) procedure utilizing discharge data collected from six gauging stations located within the region tested to be hydrologically homogeneous. The annual maximum discharges of the gauging stations were analyzed to develop: a regional frequency curve; regional regression equations to estimate peak annual flow for specified return periods (QT)   and a regional regression equation to estimate the mean annual flood (Q2.33) using catchment parameters. The regional regression equation developed for the mean annual flood (Q2.33) has standard error (Se) and coefficient of determination (R2) values of 0.08175 and 0.9613 respectively.  The equation can be applied to sites whether gauged or ungauged within the region to estimate the design flood (QT) needed for hydrologic modeling and engineering design of hydraulic structures. The IF procedure is particularly useful in developing countries where missing or inadequate data situation exist.


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eISSN: 2467-8821
print ISSN: 0331-8443