Surface soil dynamics due to Bakolori Dam construction along Sokoto River channel in the Sokoto-Rima River Basin

This Paper is an assessment of the downstream response of the surface soil of the Sokoto River channel sequel to the construction of the Bakolori dam in the late 1960’s. It adopted several methods including systematic and purposive sampling techniques for choosing the sample sites during the reconnaissance survey; onsite field observations and measurements for data collection and the use of secondary information which lasted over 24 months (June, 2007 - November, 2008). The soil survey and land classification report (FAO, 1969) and previous studies as well as laboratory and GIS analysis of data provided the needed inferences. The hypothesis that the Bakolori dam has not caused significant changes in the surface soil characteristics of the Sokoto River storm channel, were tested using the analysis of variance (ANOVA). The results revealed significant changes in the surface soil characteristics between pre dam and post dam conditions, showing a significant impact of the dam on the variables. Consequently, the working hypothesis was rejected. However, using the concept of Cumulative Effect, it was concluded that the Bakalori dam has significant effect on the Sokoto river storm surface soil characteristics but with other factors playing roles in the final outcome.