Evaluating the potential effectiveness of structural flood mitigation measures on river Nabuyonga in Mbale city

Abstract

The Nabuyonga River in the northern division of Mbale City has been facing an alarming increase in flood frequency, with significant events occurring in 2019 and 2022. Heavy rainfall, rapid urbanization, poor agricultural practices, and climate change are the main contributors to these floods. The impacts have been severe causing tremendous effects such as displacement of residents, destruction of homes and property, and loss of lives. Public health hazards, such as cholera, dysentery, diarrhea, and typhoid, have also emerged as significant concerns due to flooding. Although measures, like planting bamboo trees along riverbanks, have been implemented, they are not sustainable long-term solutions due to deforestation and other man’s related activities. There is a critical need for long-term structural measures that prioritize sustainability to mitigate future floods. Flooding along the Nabuyonga River has caused not only property damage but also economic losses and increased exposure to water borne diseases.Without any intervention, the situation may severely impact the political, economic, and social aspects of Mbale City. Stakeholders are urged to devise effective solutions to mitigate the disastrous effects of flooding. The implementation of this research could profoundly impact Sustainable Development Goals 6, 11, and 13. The main objective of the study is to evaluate the potential effectiveness of structural flood mitigation measures and suggest the most effective measure. The study will focus on the geographical area of the Nabuyonga River in Mbale City within the Namatala watershed.The research will be conducted over a four-month period and will not account for climate change impacts.The study seeks to reduce flood risk and vulnerability along the Nabuyonga River’s floodplain throught the integration of hydrological models using software such as HEC-HMS and hydraulic models using HEC-RAS.Levee,channel straightening,detention basin or floodwall design will be done using the HEC-RAS.