Title: The utility of participatory geographic information systems in the assessment of flood vulnerability in a local community setting

Abstract

Participatory Geographic Information Systems (PGIS) integrates local knowledge (perceptions and experiences of people) with conventional scientific knowledge, and has been employed in many areas of development research and application. Researchers and flood managers in Nigeria have largely ignored PGIS approaches, employing mainly a reactive, top-bottom post-flood strategy of relief and rescue. This study employed PGIS to conduct a flood vulnerability assessment in some local communities in Lokoja, Nigeria, which experience seasonal flooding with devastating consequences. The objective was to integrate the people’s perception and experiences with conventional science to investigate their vulnerability to flooding. Datasets utilized include Landsat imageries, digital elevation model (DEM), and soil samples. Spatial multi-criteria evaluation using the analytical hierarchy process was employed to analyse 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.