Spatio-Temporal Pattern of Water Hyacinth on Asa River, Ilorin, Kwara State, Nigeria

Abstract

The study aims at assessing the spatio-temporal impact of water hyacinth on the Asa River, Ilorin, Kwara State. The objectives are to examine spatio- temporal distribution of water hyacinth between 2000 and 2020; determine the rate of change in water hyacinth distribution in the study area; and forecast water hyacinth coverage on the river course by year 2030. Satellite image covering the dam for specific duration was used for determining the change and rate of change in spread of water hyacinth on the dam. The satellite image was sourced from United States Geological Survey (USGS) earth explorer. Linear regression was used to forecast the spread of Hyacinth by the year 2030. The study reveals that water hyacinth distribution increases around the river from 2000 to 2020. As at 2000, the portion of the dam overgrown with water hyacinth was less than 0.028 sq km of the area covered by the river and increased to 0.664, and 2.735 sq km in the 2009 and 2020 respectively. The increase in water hyacinth coverage began at the downstream of the river where pollutants are deposited before engulfing the surroundings of the river. The forecast shows that Water hyacinth will cover about 3.9 sq.km by 2030 if no measures is put in place to mitigate the current growth rate. The study concludes that water hyacinth covers Asa River and recommends the implementation of an integrated management approach that combines mechanical, biological, and chemical control methods to effectively manage water hyacinth infestations in the Asa River.