Analysis of storm runoff-sediment yield of a 1st order stream basin in Obafemi Awolowo University, Ile-Ife, southwestern Nigeria

Abstract

The aim of this study is to examine the relationship between storm flow discharge and storm sediment yield of a 1^st order stream basin in the degraded forested part of Obafemi Awolowo University, Ile-Ife. The study was carried out between August and October, 2002 and six storm events that occurred during the day were sampled.

The results of this study showed that in some of the storm events observed (storm event 1, 4 and 6), the storm flow discharge correlated significantly with the storm yield (with r-value of 0.743, 0.591 and 0.576 at α = 0.05, respectively) while in other events such as storm events 3 and 5, the storm runoff/discharge was poorly correlated with the storm yield with r-values of 0.102 and 0.330, respectively. Therefore, these findings indicated that sediment load was not a capacity load and thus should not be expected to increase always with increase in storm flow discharge. The findings of this study will aid programme in soil erosion controls designed by the governments and individuals in forested watersheds.

Key Words: Storm flow discharge, storm sediment yield, sediment concentration and land use.

Ife Journal of Science Vol.6(2) 2004: 185-190