Responses of Some Basin Parameters to Landuse Changes in Ilorin City, Nigeria

摘要

This study is an assessment of the responses of some basin parameters to land use changes in Ilorin, Nigeria. To achieve this central tenet, the following specific objectives have being pursued as follows: to examine the relationships between the basin channel morphometries, to identify the land use types and their effects on the catchments; and to evaluate people’s awareness on land use management problems. Thus, data were generated through direct measurement of some basin properties such as width and depth and also using simple random sampling technique questionnaires were also administered. Further, the use of multiple regression analysis and descriptive statistical techniques were employed for the analysis of the data collected and thus, the results show that: General channel enlargement occurred in width dimension in all the 4 drainage basins, which can be attributed to high sediment yield within the 4 drainage basins. Also, there is a significant difference (95%) between mean upstream channel width and mean downstream width in the 4 basins which confirms an increase in channel width with distance and channel depth decrease. Further, channel changes in the downstream areas below the urban areas are generally substantially larger than predicted from the natural channel cross sections upstream. Thus, the basins exhibited different spatial pattern downstream, which can be associated with differences in degree of land use pattern within the basins. Generally, different measures have been suggested to curb the menace of land use problems, within the drainage basins. This includes the evacuation of the areas close to drainage basins, legislation against riverside building, diversion of river course from residential areas, engineering methods among others.