Background: Populations in coastal cities are exposed to increasing risk of flooding, resulting in rising damages to health and assets. Local adaptation measures, such as early warning systems for floods (EWSFs), are urgently needed to reduce the risk and impact of flood events. The aim of this study was to assess community perceptions and self-reported actions in response to flooding in a tropical coastal city to inform flood risk reduction policies and programs.Methods: This qualitative case study was conducted in flood-prone areas in Machala, Ecuador, a coastal city exposed to seasonal floods and extreme floods during El Niño events. Adult community members from three periurban sites were invited to participate. Focus groups discussions (11 focus groups in total) were held with community members (n=65 people) from September to November 2014 to assess perceptions of flood exposure, sensitivity, adaptive capacity, and current alert systems. Focus groups discussions were audio recorded, transcribed, and coded by topic; participatory maps were field validated, georeferenced, and digitized using GIS software. Results: Community members identified the presence of annual flooding during the rainy season, as well as greater than normal flood events (depths ranging from 0.5 to 3 meters), which recurred every 3-4 years in some communities. The deepest floods occurred during the 1982 and 1997/1998 El Niño events. Community members perceived that exposure to flooding depended on the rainfall coinciding with high ocean tides, and geographic proximity to blocked drainage areas, canals, and low local elevation. Participants reported that children were the most sensitive group due to increased susceptibility to skin infections and mosquito borne diseases (i.e., dengue fever). Other sensitive groups included the elderly, physically handicapped people, low-income families, and recent migrants. They identified persistent social-ecological vulnerabilities that increased flood risk and exposure in the urban periphery, such as inadequate access to garbage collection, homes settled in precarious low-lying geographies, economic barriers, lack of political access, and lack of social mobilization. In addition, communities expressed a lack of social capital (e.g. political voice), despite the existence of formalized community councils. Key neighborhood resources with respect to flooding included green areas, schools, nurseries, fire stations, health clinics, police stations, a retention wall (berm), and an emergency meeting place. Challenges for adaptive capacity existed primarily in actions related to the preparation and recovery stages of flooding. Despite the presence of an official flood warning system, community member relied on informal communication channels via social media. Conclusions: The flood vulnerability assessment framework and participatory research process utilized here can potentially inform studies in other flood-prone regions to guide the development of EWSFs and other climate change adaptation policies and actions.
Joint impact of rainfall and tidal level on flood risk in a coastal city with a complex river network: a case study for Fuzhou city, China