Geospatial Analysis of Land Use Change and Wetland Dynamics in Kaduna Metropolis, Kaduna - Nigeria

Abstract

Wetlands are among the most precious ecosystems in the world, sensitive to changes in land use, affecting their distribution, health, quality, functions and provisioning services they provide. This study assessed how land use change and socio-economic activities are driving wetland conversions in Kaduna Metropolis from 1986 to 2020. Landsat images (189/053) and SRTM DEM were obtained from USGS. These images were processed using ERDAS Imagine 2014 and the study area was extracted using mask tool. Decision-tree classification was used to identify and map the wetlands in the study area, and indices-based classification using eCognition 9.0 was used to carry out the land use land cover change detection. Result of the analysis showed an overall accuracy of 94% (0.93 Kappa) for 1986 classification, and 90% (0.88 Kappa) for the 2020 classification. The study revealed that only the built-up areas increased from 72.47 km2 to 239.88 km2, riparian vegetation reduced from 88.39 km2 to 70.96 km2, open water bodies reduced from 6.67 km2 to 4.89 km2, agricultural land also reduced from 424.80 km2 to 356.99 km2, bare land reduced from 169.22 km2 to 101.21 km2 and undisturbed vegetation also reduced from 150.39 km2 to 138.56 km2. The study concluded that settlement expansion as the primary driver of wetland changes in Kaduna metropolis. The study therefore recommends creation of buffer zones around the wetlands in order to prevent further encroachment.