Assessment of areas at risk of floating islands on the shores of lake victoria

Abstract

The purpose of the study was to assess the risk of floating islands on Lake Victoria. Floating island are good habitants for both birds and animals, they filter water, help in turbulence stabilisation but they also pause some threats such as disruption in water transport, fishing and other economic activities, destruction of property and infrastructure . In 2020 a floating island moved from Murchison Bay towards Nalubbale power dam causing a country wide power blackout on 14th April 2020. This research integrated the GIS tools and Analytical Hierarchy Process (AHP) for assessing risk of floating islands on the shores of Lake Victoria in Uganda. To map the floating islands prone areas, six potential independent variables were selected as effectual factors, including Rainfall, human activities (Distance from industries, and fishing grounds/Landing Sites), Flow Accumulation, Wind flow, and Land cover (water hyacinth, vegetation and water). These were mapped basing on inventory reports, satellite image processing and field survey using handheld GPS. Because of the inconsistences in the data types of the independent factor, they were reclassified by assigning preference values depending on their level of influence. It was determined that rainfall has a high influence on floating Islands. The risk of floating Island was grouped into Low, Medium, and High. The risk of floating Islands was found to be high near landing sites as at Kasensero , Kyabasimba and Kasembo Landing sites . The risk was relatively low within areas away from the shores.