Integrating geospatial mapping and stakeholders’ perception on sustainable flood solutions in a typical coastal megacity of Nigeria: a SWOT-AHP approach

The study involved the identification of urban flood-prone areas, followed by surface inundation mapping and the development of strategic flood solutions using an integrated approach. Digital elevation modeling of the satellite images and Sentinel-2 data, along with spatial rainfall data, was integrated for assessing spatial flood vulnerability using a Geographic Information System (GIS) approach. In addition, questionnaires were administered to participants on 40 elements outlined in the SWOT survey instrumentation, and responses were analyzed. The findings revealed high flood vulnerability in the study area, particularly the densely populated metropolitan areas with inadequate drainage infrastructure. Rainfall patterns during the June–July–August (JJA) and September–October–November (SON) periods were linked to flood frequency and high surface inundation, highlighting the need for early warning systems and drainage improvements. The Strengths, Weaknesses, Opportunities, and Threats-Analytic Hierarchy Process (SWOT-AHP) framework highlighted flood strategies across four thematic pillars: environment (0.45), legal and institutional (0.22), socio-economic (0.16), and urban engineering (0.16). Strategic alternatives were ranked based on global weight values and categorized into short-term strategies focused on critical infrastructure and evacuation planning. Mid-term priorities included green infrastructure and smart monitoring systems, while long-term strategies emphasized sustainable urban planning and regulatory enforcement. The findings also underscore the need for a more integrated policy implementation, community engagement, and improved investment on adaptive infrastructure to reduce flood risk. The structured decision-support tool suggested proactive, sustainable, and inclusive flood resilience strategies for stakeholders.