Assessment of flood vulnerability in some communities in Lokoja, Kogi State, Nigeria, using Participatory Geographic Information Systems

Lokoja, the capital of Kogi State, Nigeria, experiences seasonal flooding with devastating consequences on the people and the natural and built environments. In contrast with developed countries, researchers and flood managers in Nigeria have largely ignored Participatory Geographic Information System, which integrates the perceptions and experiences of the people affected by flood events with technical, conventional methods, as a flood management strategy, with flood managers employing a reactive, top-bottom post-flood strategy of relief and rescue. This study employed PGIS to conduct a vulnerability assessment in Lokoja as a pre-flood strategy that involves the communities. Datasets utilized include Landsat imageries, DEM, and soil samples. Spatial multi-criteria evaluation using the analytical hierarchy process was employed to analyze flood parameters determined through community participation to evaluate vulnerability while consistency ratio was also calculated to ensure that the comparison of criteria made was consistent. Results revealed that elevation is the most important factor, and land use, among other parameters of flood vulnerability. Out of a total area of 6, 258 Ha, 4, 445 Ha are highly vulnerable and 1, 815 Ha being moderately vulnerable. Comparison consistency ratio was determined to be 0.08 which is acceptable. Based on the results, this study concludes that the perception of affected communities can complement conventional flood research for a more effective response and mitigation strategy. The research therefore recommends the integration of geospatial techniques and participatory approaches for flood vulnerability studies for a proactive, bottom-up approach to flood management. •The study area (Lokoja, Nigeria) experiences flooding almost annually. Researchers and flood managers in Nigeria have largely ignored participatory geographic information system (PGIS) for flood management, and flood managers pay more attention to a top-bottom, post-flood management strategy.•The study employed PGIS to conduct vulnerability assessment as a bottom-up, pre-flood management strategy, taking into account the perceptions and local knowledge of community members.•Community local knowledge and perceptions were integrated into a multi-criteria evaluation using the analytical hierarchy process to assess vulnerability.•Results provided a weighted ranking of flood vulnerability parameters, and a demarcation of study area into highly, moderately, and non-