Monitoring the land-use and vegetation cover changes in the Kainji Lake Basin, Nigeria (1975-2006)

Abstract

This paper demonstrates the use of remotely sensed data and geographic information system (GIS) techniques for monitoring the land-use and vegetation cover changes in the Kainji Lake Basin between 1975 and 2006- a period of thirty one (31) years. Since 1968 when Kainji Lake was constructed, various activities such as agriculture, deforestation, irrigation, fishing and construction of roads and bridges have taken place. It is all these activities coupled with other natural factors that cause environmental degradation and the damage of the ecosystem of the lake basin. Landsat TM image of 1975, Landsat MSS image of 1986 and Landsat ETM+ images of 2001 and 2006 were acquired, classified and analysed with the use of Ilwis 3.3 and Idrisi 32 to study the landuse and vegetation changes in the Lake Basin between 1975 and 2006. Area calculations of Idrisi 32 were used to derive the trends, rates and magnitudes of changes, while map overlay was employed for assessing the nature and location where the changes have taken place. Map overlay technique was also used to create a matrix to discuss the location of the changes within the study periods. The study reveals that the Lake Reservoir and settlements around the lake were gradually increasing; intensive agriculture was capturing the basin at alarming rate, while the lake surface itself is recently been occupied by weeds. The woodland vegetation in which the first and the most popular National Park in the country where it is located is also discovered to be changing to other land-use types. Various conservation and control measures were suggested for the sustainable utilization of the Lake Basin.

Key words: Remote sensing, geographic information system (GIS), image classification and land-use and landcover, change detection.