Urban Growth Dynamics and Land use Change in Port Harcourt Metropolis, Nigeria between 1986 and 2020

Abstract

This study evaluated the urban growth dynamics and landuse change in Port Harcourt Metropolis for five epochs, namely: 1986, 1990, 2000, 2010 and 2020, with the application of geo-information techniques. The landuse/land cover (LULC) classification and change detection due to urban growth on a decadal basis was retrieved from multi-temporal Landsat 4 & 5 Thematic (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI), and Thermal Infrared Sensor (TIRS) images at a spatial resolution of 30m. Supervised classification using maximum likelihood algorithm classifiers was used to classify similar spectral signatures into various major classes which included vegetation cover, farmland, water bodies, built-up area and open space/bare soil. The area of each landuse class was computed in ArcGIS 10.5 which was used to compute the landuse change and percentage change in squared kilometres. The findings indicated that the landuse pattern of the city has momentously been dynamic and most of these changes are driven by the progression in the growth of the city. Between the period of 1986 and 2020, waterbodies and built-up area increased by 3.61% and 172.59% respectively; while thick vegetation reduced by 33.06%, riparian/swamp forest and farmlands decreased by 13.02% and 19.96% respectively; signifying spatial expansion of the urban centre to the detriment of other landuses, notably thick vegetation. On the premise of the findings, the study recommends that regulatory authorities should strictly control urban growth and be dogged with the enforcement of planning regulations; landuse planning and mapping should be routine course of action for the authorities and urban growth should be frequently monitored by the governments so as to be able to detect slightest changes in the city’s morphology.