Urban Expansion and Land Use Land Cover Change Analysis in Oyi Local Government Area, Anambra State

Abstract

Nigerian cities have been experiencing rapid urban expansion over the last few decades, contributing much to the region's land cover transition into the metropolitan area. The study aims to employ geospatial techniques to investigate land use and land cover changes inOyi Local Government Area of Anambra State. The Landsat Thematic Mapper, Enhanced Thematic Mapper plus and Operational Land Imager satellite imagery for 1998, 2003, 2008, 2013, 2018, and 2023 were downloaded from the USGS Earth Explorer website. The ArcGIS 10.8 was utilisedforthe compilation, analysis, and distribution of geographic data, and the image classification was carried out using this software. Idrisi Selva 17  was used for change detection analysis and transition rates analysis. The images were then divided into five major categories namely farms/shrubs, built-up area, riparian vegetation, bare surfaces, and forested area using a maximum likelihood supervised classification. The results of the study revealed a significant increase in built-up areas from 1.5 sq.km in 1998 to 42.9 sq.km in 2023. This expansion occurred at the expense of dense vegetation, which decreased from 94.9 sq.km to 18.6 sq.km, and sparse vegetation/farms/shrubs, which saw a net change from 48.4 sq.km to 86.8 sq.km with inter-epoch variations. Bare land decreased overall from 4.9 sq.km to 1.3 sq.km. The change detection analysis highlights that 33.2 sq.km of dense vegetation and 6.8 sq.km of sparse vegetation were converted to built-up areas. Findings reveal the urgent need for sustainable urban planning and environmental monitoring to mitigate the adverse impacts of unplanned expansion. Hence, the study recommends thatthe Anambra State Geographic Information System and Anambra State Physical Planning Board strictly and periodically monitor urban growth to ensure sustainable development and environmental protection.