Assessment Of Geomorphological Characteristics And Land Use Change On Kiserian River Catchment In Kajiado County

Abstract

Urbanization process increases impermeable surface which causes change in stream discharge. Streamflow variability is the most important element in geomorphological process of erosion and sediment transportation. This study aims at assessing geomorphological characteristics and land use change on Kiserian River Catchment in Kajiado County. The research utilized a sample size of 100 household heads determined by (Nasuirma, 2000). The researcher employed statistical package for Social sciences (SPSS) to analyze data using percentages presented in tables, bar graphs, pie charts and comparative bar graphs. The specific objectives were to examine the mean annual rainfall and its relationship to landforms, determine spatial and temporal land use change, and assess the impact of human activities (quarrying, agriculture, and urbanization) in the Catchment area. The study covered the period from 1972 to 2017. The overall goal was to assess the impact of urbanization on the life span of Kiserian dam. Both Primary and secondary sources of data were used in the study. Structured questionnaires and interview schedule were administered to household heads. Impermeability of the catchment and River bank erosion were obtained through observation and photographs. Secondary sources provided information on mean annual rainfall. The results indicated that there has been gradual increase in mean annual rainfall shown by the three equations in Figures 4, 5 and 7. Land use change was done from satellite imageries obtained from Regional Centre for Mapping of Resources for Development (RCMRD). The results show that there has been spatial and temporal land use change on Kiserian River Catchment of which forest cover increased from 20.03% in 2009 to 23.46% in 2017. Cultivated, unused and bareland increased from 18.8% in 1984 to 38.04% in 2017. Grassland and vegetation reduced from 1984 to 2017. Waterbodies depict 0% in 1984 to 1995. In 2009, Waterbodies occupied 0.05% then reduced to 0.4% in 2017. Findings indicate that human activities are dominant and are the major causes of catchment degradation. To understand how human activities and rainfall influence streamflow, can enable planners to formulate policies towards minimizing undesirable effects of future land use change on streamflow. The research recommends heightened conservation measures to protect Ngong forest, to control anthropogenic activities and to equip Rain Stations with modern automated equipment’s to record and transmit data in real time to central stations for analysis and action.