Planform Analysis of the Kafubu River in Ndola Urban, Zambia (1993-2015)

Abstract

Land use change mostly due to rapid socio-economic development has potentially large impacts on water resources. This study was carried out to determine the quantitative areal extent of the planform changes of Zambia’s Kafubu River over a span of 22 years (1993-2015) with the utilization and application of remote sensing and Geographic Information Systems (GIS). The Kafubu River mainly lies in Ndola District of Copperbelt Province in Zambia. The study focused on the section of the river that is in the urban area of Ndola covering 3.6 km out of the total 40km. The analysis has been conducted using aerial photographs of the study area taken in 1993 and 2015 and a 2009 IKONOS satellite image which were used to generate object based classified land use maps and change detection maps. The rates of erosion and accretion were used to interpret the planform analysis of the river. Shapefiles of the river were analysed in order to determine bank line shifts during the study period. Findings of the study were that some of the river buffer zone 50m on either side of the river had changed from crop land use to residential areas. The built up area in the study area had increased from 41.54ha in 1993 to 198.46ha (377.76%) in 2015. Results further show that the surface area of the river had reduced by 53.21 percent. The rate of accretion (max 1.27 m/year) was found to be higher than that of erosion (max 0.2 m/year) which suggests an overall reduction in channel width. Factors attributed to causing land use changes were shortage of state land, corruption in allocation of land, proximity to central business district, population increase, ignorance of environmental issues, and poor planning by the Municipal Council.