The Impact of Human Population on Land Cover Changes in Gwassi Hills Water Tower, Homabay County

Abstract

Population growth has been pointed out as a main driving factor for land cover changes, mainly in developing countries. About 80% of Kenya’s economy is sustained by land-based resources, implying that as population increases there is likelihood of over-exploitation of these resources leading to massive land cover changes. Information on agents causing land cover changes is key during decision making on sustainable conservation of natural ecosystems. In this regard, this research sought to examine the impact of population density and urban sprawl on land cover changes in Gwassi hills water tower located in Suba South Sub-county, Homabay County. The research used data from satellite imageries downloaded from Unites States Geological Survey and population census from Kenya National Bureau of Statistics as well as 100 square kilometre gridded population from Worldpop Open Spatial Demographic Data and Research. The data acquired were for years 1989, 1999, 2009 and 2019. Random forest algorithm method was used to generate supervised land cover classification in R-studio. The data was processed and analysed in ArcGIS 10.8 and presented inform of tables, maps and graphs. Overlapping Neighbourhood Pearson correlation coefficient analysis was used to determine the relationship between population density and land cover changes. Chi-square was used to assess the influence of urban sprawl on land cover changes within ten towns in the study area. The study findings showed that population density in Gwassi hills water tower had risen from 89 persons/km2 in 1989 to 229 in 2019. Land cover in the study area has also been changing over time where area under forestland, grassland and built-up areas increased while bareland declined between 1989 to 2019. In addition, urban sprawl has also been witnessed in the water tower with built-up areas within towns expanding by 93% between 1989 and 2019. These land cover changes were attributed to devolution of Government services, restoration efforts and improved infrastructure. The study established that there was significant relationship between population growth and land cover changes in Gwassi hills water tower. It also found out that land cover changes in the urban areas was significantly influenced by urban sprawl. Thereafter, the study concluded that land cover changes in the water tower is expected to continue happening in favour of cropland and built-up areas to meet demands of the ever-increasing population and urban areas. It is recommended that there is need to promoting sustainable land management and conservation of water catchment to mitigate land cover changes related to anthropogenic factors.