Time series analysis of the impact of water level variability on the flooded area along the shores of Lake Victoria

Abstract

Lake Victoria is the largest freshwater lake in Africa and plays a crucial role in the livelihoods of the communities residing in its vicinity. The lake's water levels are subject to natural fluctuations caused by climatic and environmental factors, as well as human activities. The aim of the study is to investigate the relationship between water level variability and the flooded area along the shores of Lake Victoria through comprehensive analysis of historical water level data and corresponding flooded area to identify patterns, trends, and potential causative factors. This study aids a better understanding of the dynamics between water level variability and flooding in the Lake Victoria region. In addition, it provides insights into the vulnerability of the adjacent areas to flooding and support the development of effective mitigation strategies. Furthermore, it sheds light on the potential impacts of climate change on water levels and associated flooding patterns, highlighting the need for proactive measures. Altimetry Time series Software (ALTiS) is used to obtain historical water level data from SENTINEL 3A RADAR altimetry data and corresponding flooded area computed from SENTINEL 1 imagery. Autoregressive integrated moving average (ARIMA) modeling, is applied to uncover patterns and relationships within the data and statistical tools are utilized for data analysis and visualization. The Pearson’s correlation coefficient of 0.752 obtained suggests a strong positive linear relationship between water level and the extent of the flooded area along the shores of Lake Victoria. The analysis of graphical representations reveals stable, upward and downward trends in water levels allowing for a comprehensive understanding of the impact on flooding. Based on the results and analysis, there is significant influence of water level variability on the flooded area along the shores of Lake Victoria. The water level of Lake Victoria is observed to gradually fluctuate during the period 2018 to 2022. Finally, there was damage to infrastructure such as roads and buildings by the floods although it was only limited in areas in close proximity to the shores of Lake Victoria (within the buffer zone of 200m).