Evaluation of rainfall-runoff modelling data in Sebeya Catchment, Rwanda - Recommendations for improved flood hazard analysis

Sammanfattning: Rwanda has experienced an increase in the frequency of riverine floods since the mid 2000s, and the future impact of climate change on the hydrological cycle is uncertain. Flood hazard analysis is one tool used to reduce flood risks; the analysis is often based on models which requires hydrological and meteorological data. New hydrological measurement stations have been installed at select locations in Rwanda, such as Sebeya Catchment. This thesis evaluated the role of hydrological models in flood hazard analysis in Rwanda by reviewing previous hydrological studies and evaluating a HEC-HMS rainfall-runoff model of Sebeya Catchment. The hydrological telemetry data was found to not be suitable for a continuous model due to the short timeseries and the long-term daily stage data lacked rating curves. The rainfall data was only available as daily recordings, unsuitable for event-based models. To improve the performance of hydrological models in Sebeya Catchment, it is proposed that alternative data, such as satellite rainfall data, are investigated. To improve the data available in Rwanda required for hydrological modelling capacity building in database management is recommended within Meteo Rwanda and Rwanda Water Resources Board. In addition, the locations and installation process of new hydrological stations should be reviewed.