Flood vulnerability and coping mechanisms around the Weija Dam near Accra, Ghana

Abstract

This paper argues that flood vulnerability around the Weija Dam, near Accra, the capital of Ghana, can be explained by the city’s complex peri-urbanization trajectories. The dam, which was constructed 40 years ago, supplies water to many parts of the Greater Accra Metropolitan Area. To offset the impacts of potential dam failure due to seismic activities, as well as accidental and planned water spillages, about 100 m of lands around the dam and 30 m of riparian lands around River Densu were reserved. Despite planning prohibitions, these reservations have largely been encroached by homebuilders and business operators. Analyses of time-series rainfall data and hazard mapping showed that during periods of torrential rainfall, the dam and the river are overwhelmed with storm water hence exposing the Weija Township located downstream to flood hazards. Questionnaire surveys, in-depth interviews with selected homebuilders, and institutional consultations revealed that the spatial and institutional management dynamics, customary land ownership, along with the growing defiance of planning regulations were the key influences of floods in the Weija Township. The affected households have attempted to mitigate the effects of flooding by elevating structures with stones and sandbags, strengthening walls, constructing drains and pumping water out during flooding events, but with little success. However, given the lack of political will to remove the unauthorized structures constructed within the buffers and reservations, the challenge now is to minimize flood vulnerabilities by flood-proofing buildings, improving drains and channelizing portions of the river within the township. These structural measures should be complemented by flood vulnerability maps, early flood warning and evacuation systems, mandatory property insurance policies, and above all, improved institutional coordination and collaboration for flood management. The paper recommends a re-examination of Ghana’s urban land use planning and management of water bodies in urban areas.