Sediment Loss Responses to Rainfall on Different Surfaces in Obudu, Cross River State, Nigeria

Abstract

The amount of runoff generated relative to different surface types given an amount of rainfall is very important in hydrogeomorphological studies. This study is aimed at examining sediment yield responses to rainfall on different surfaces in Obudu, Cross River State, Nigeria. Data were collected on rainfall amount, intensity, duration and sediment loss from three run off plots on natural vegetation surface, mulched and bare surfaces. The data collected were analyzed using Pearson’s moment correlation and multiple regression statistical techniques. The results revealed that rainfall amount correlated positively with sediment loss on  vegetated, mulched and bare surfaces with r-values of 0.58 (p<0.01), 0.57 (p<0.01) and 0.95 (p<0.01) respectively. Rainfall intensity correlated positively with sediment yield on the vegetated, mulched and bare surfaces with r-values of 0.75 (p<0.01), 0.65 (p<0.01) and 0.60 (p<0.01) respectively. The negative correlations between rainfall duration and sediment loss suggests that sediment loss decreases on all the surfaces considered with r-values of - 0.15 (p<0.01), - 0.21 (P<0.01) and -0.06 (p<0.01) on vegetated, mulched and bare surfaces respectively. The study further revealed that the predictive variables explain 62.7%, 50.8 and 60.8% of sediment yield on bared, vegetated and mulched surfaces respectively as rainfall directly influences sediment loss, though the importance of surface types cannot be discarded.