| dc.description.abstract | In many locations around the world, dams are essential for flood control, water supply, irrigation,
hydropower, navigation, and recreation. This is synonymous with Uganda, where the one single
investment that would lay the foundation of industrial development was the construction of Owen
Falls dam (Nalubale dam) in 1954. Since then, other large and high hazard dams such as Bujagali,
Karuma and Isimba have been constructed majorly for hydroelectric power generation. Kabuyanda
dam, which shall be an embankment dam (earth dam), shall be the first large and high hazard dam
in Uganda solely constructed for irrigation development, with a Storage Capacity of 8.8Mm3
. For
large and high hazard dams, it is a requirement that consideration is given to the number of people,
property, infrastructure and ecosystem at risk downstream of the dam. This paper provides results
of a dam breach analysis and mapping of the downstream area to be inundated by the resulting
catastrophic dam break flood of Kabuyanda Multipurpose Dam.
Flow simulation of the dam break was performed using HEC-RAS and the results were mapped
using ArcMap. The resultant flood hazard map which was based on water depth and flow velocity
showed that the potential failure of Kabuyanda dam will cause part inundation of 31 of the 38
villages with in the irrigable command area of Kabuyanda Irrigation Scheme, thereby placing a
large number of people and property in danger. The total area to be inundated shall be up to
1,197.6 Hectares, these area accounting for 33% of the total irrigable command area. All the 31
villages to be part inundated were ranked from highest hazard potential to lowest hazard potential
and the village found to be with the highest hazard potential is Kagoto II. At Kagoto II, it is
expected that the impact of large volumes of instantaneous flow may destroy houses and flood
farmlands, resulting in significant casualties and property losses. Therefore, in the eventuality of a
dam-break, rescue attempts for the highest hazard potential villages should be prioritized. The
results of this study can be used by stakeholders such as emergency responders and the community
at risk in formulating evacuation procedure. | en_US |
