Review of flood modelling and models in developing cities and informal settlements: A case of Nairobi city

Randa O, T. Krhoda O, G. Atela O, J. Akala, H.
Academic publication
August 2022

Study region: This study focuses on urban flood modelling in developing cities with a special focus on informal settlements giving a specific case study of Mukuru slums in Nairobi city of Kenya. Informal settlements refer to unplanned settlements and areas where the housing doesn’t comply with the current housing codes and regulations and is thus characterized by a lack of legal settlement and housing plan approvals resulting in poor physical infrastructures and social services. Urban flood risks have been given less attention compared to rural riverine flooding in developing cities yet they cause more havoc. Using the appropriate set of models, flood modelling in urban settings is critical in integrated flood risk management.  

Study focus: This study uses a desk review format to promote urban flood modelling knowledge and practice in integrated flood risk management in developing cities. In this regard, the study presents the review of various flood models highlighting their strengths and weaknesses and the significant role of model calibrations in addressing uncertainties while capturing the local scenarios. The paper further presents the role of model stacking where different models are used to understand the same hazard evolution at various scales.  

New hydrological insights for the region: As developing cities grow, so do the flood risks, especially in the informal settlement. This study reveals the importance of comprehensively understanding the flood dynamics at various scales. The study points out the important role of model stacking and calibrations which allows the understanding of flood risks at various city scales for an integrated city flood risk management.