Remote sensing and GIS-based modelling of land cover change for runoff simulation.

Abstract

The Murchison Bay is a catchment located in the northern shoreline of Lake Victoria basin that supports several human related activities in Uganda. Because of this, the catchment has undergone remarkable land cover changes, over the years. This study aimed at quantifying the land cover changes between 2000 and 2020 as well as predicting the changes that will happen by 2030 in this area and simulating the runoff that will happen with these changes. These objectives were achieved through remote sensing and GIS techniques using ArcGIS 10.3 software with hydrological tool extensions added. The land cover changes were determined through classification of Landsat images in the different years and image differencing was done to determine the changes over those 20 years. The study determined that the dominant changes between 2000 and 2020 were increases of builtup land (44.09% to 50.19%), bare soil (5.28% to 9.19%) and water bodies (2% to 2.27%), and decreases in the following classes: wetlands lands (from 8.02% to 4.02%), grassland (from 30.53% to 25.5%), and trees (from 10.08% to 8.83%). Considering the driving forces responsible for the change, LRM was used to stimulate and forecast LCC over time till 2030. This procedure showed that the built-up class will keep expanding further for the same reasons such as population growth. By 2030, the built-up class will occupy 59.52% of this area. Surface runoff is the flow of water occurring when the soil is infiltrated from rain and other sources flow over land to maximum capacity and excess water. It is a major component of the water cycle and a key agent for soil erosion, floods and water contamination. The predicted land cover transformations will obviously have some negative environmental impacts among which is increased surface run off, by 2030, the simulated surface run off will have the deepest as 32mm by 2030.