An evaluation of the change in land use/land cover and terrain characteristics of Ala River catchment, Akure, Nigeria.

This study evaluates land use change within the upper catchment area of Ala river, Akure, Ondo State over a period of 31 years (1986-2017) using Landsat Thematic Mapper (TM) 5 of 1986, Landsat Enhanced Thematic Mapper Plus (ETM+) 7 of 2002, and Landsat 8 OLI / TIRS of 2017. The normalized difference vegetation index (NDVI), surface runoff and terrain configuration within the study area were analysed using ArcGIS 10.5 software. Three land use types were identified namely; built up, vegetation and bareland/outcrop. The built up covered 29.39 % in 1986 and increased to 43.64% in 2017. Vegetation revealed a reverse trend with a continuous decline from 49.21% in 1986 to 14.16% in 2017 while bareland/outcrop increased from 19.60% in 1986 to 42.20% in 2017. The NDVI values range between -0.03 and 0.4; -0.3 and 0.3; and 0.04 and 0.3 in 1986, 2002, 2017, respectively as an indicator of vegetation degradation. The analysis showed that the study area has been considerably degraded, mainly due to the depletion of vegetation and uncontrolled urbanization process. It is therefore recommended that the government through its physical planning agency, put in place effective control mechanism to guide physical development that will enhance sustainable development in the study area and other parts of the town.