Effect of Land-Use/Land-Cover on Peak Discharge of Rivers in Benue State, Nigeria

Abstract

The paper analysed the influence of Land-use/Land-cover (LULC) change on peak discharge in Benue State, Nigeria over the period of 40  years (1982-2022). This study employed Geographic Information System (GIS) and Remote Sensing (RS) techniques and methods to map  and quantitatively assess the variations in land-use land-cover classes within an interval of ten years. That is, 1982 to 1992, 1992 to 2002,  2002 to 2012, and 2012 to 2022 respectively and relate changes to hydrological data (peak discharge) to aid the investigation of the  relationship between changes in land-use land-cover classes and peak discharge within the study area. The study adopted a survey and  observational methods of research design. A sample of 399 respondents was selected using a multi-stage sampling procedure. From the  analysis, it was observed that there is a significant decrease in forest land-cover with an annual decrease rate of 2.41% within the 40 years (1982 to 2022) while cropland and pasture land increased with an annual rate of increase of 1.68%, built-up area 37.42% Water body  0.67%, and bare land with 6.50% annual rate of change. These land-cover changes have the potential to create an environment conducive  to enhanced surface runoff and, as a result, an increase in discharge in the River Benue. The trend of peak water discharge in River Benue  shows a 24.23% increase in peak discharge from 1982 to 2022. The influence of land-cover change and peak discharge shows  significant influence (R=0.849, R²=0.721, F=13.4, P<0.01) of change in forest cover, cropland/pasture land, built-up area, water body, and  bare surfaces on peak water discharge in the area. These show that changes in landcover are considerably contributing to the flood- producing mechanism, implying that, all things being equal, flood episodes in the region will continue to increase in frequency, severity,  and impact in the area. The study recommends halting activities that lead to tree loss and adopting sustainable agricultural practices as  vital mitigating measures of LULC change influence on water discharge in river Benue in the area.