Flooding in Weija Gbawe Municipality, Ghana: A Mixed-Method Analysis of Human-Induced Causes, Environmental and Socioeconomic Impacts and Mitigation Gaps

Abstract

The persistent occurrence of flooding in the Weija Gbawe Municipality, Ghana, is not just a mere local environmental issue; it has aftereffects on the environment and the affected communities as well. A case study of recurring floods was undertaken through interviews and geospatial methods, including administrative input from local government authorities on the one hand and detailed surveys involving questionnaires with approximately 70 people drawn from flood-prone areas on the other hand. The latter were examined using established methods involving Geographical Information Systems (GIS) on wetness tendency, soil moisture, elevation, and slope patterns, with remote-sensed flood-prone areas mapped. Respondents provided a variety of responses on causes of flooding, with the majority indicating poor drainage (19.61%) and poor waste management (16.72%) as the leading causes. Construction of structures in waterways was cited by 16.08% of respondents; other causes included heavy rainfall (13.5%) and dam overrunning (13.18%). Also remarkable are the percentages of other effects of the flood: economic disruption for 37.14% of the people, property damage for 42.86%, and displacement and disease for 10% and 11%, respectively. Notably, a staggering share of 54% of residents reported having no plan for evacuation in the event of flooding, and among those who did have evacuation plans, 72% stated they would only move to higher ground if a flood occurred. The magnitude of the risk was quantitatively characterized in the spatial analysis, which showed risk clustered in low-lying areas with flat slopes and high topographic wetness indices, and that the areas closest to the Densu River were the most affected. Residents identified uncontrolled urbanization, lack of adequate drainage, and lack of enforcement of building regulations in these areas as the most pressing problems causing flooding. The authors hope that the combined qualitative and geospatial methods of investigation offer new insights into the vulnerabilities of peri-urban communities and gaps in their mitigation efforts. Given their earlier discussions, it would be useful to explore some of the key points that can be extracted from the analyses. These points are not just academic; they have considerable relevance for urban planning efforts, especially in the coastal cities of West Africa, where flood risk has a poignant significance.