Health risks associated to vulnerability of water and sanitation systems in face of climate extreme events in a West African medium-sized city

Introduction: The frequency of extreme weather events associated to climate change like floods have increased in West Africa over the past several years. This study undertook an assessment of the risk factors and vulnerabilities related to water and sanitation systems in the face of repeated flooding events within a West African mid-sized city. Methods: A multidisciplinary (household and geographical) survey was undertaken after the rainy season, covering the whole city of Korhogo in Cote d’Ivoire and targeted 600 households. GPS devices were used to geo-locate major environmental factors including wells and other potential breeding sites for water-vectors. The identified risks have been analyzed considering historical climate data series for temperature and rainfall (1971 – 2001) and the potential consequential projections for 2020, 2030 and 2050. Results: For the Korhogo area, the climate projections would indicate an increase in the mean temperatures of 0.44°C, 1.13°C and 1.96°C for 2020, 2050 and 2080, respectively. The associated maximum temperature increases projected are 0.31°C, 1.36°C and 1.17°C in 2020, 2050 and 2080 and for rainfall the projections indicated an increase of 24%, 29% to 33% and 12% to 28% for same horizons. We found 347 wells in the area and 325 stagnant wastewater points; 60% of households have their own wells in the yard, 63% report using water from wells for drinking purposes, 90% have latrines in the yard, very often located at less than 15 meters from the well, 15% of a total of 429 water points yielded a positive result when screened for presence of Anopheles larvae. Conclusions: Considering the assumed projections of increasing rainfall with a possible continued deficit in the drainage systems in small and mid-sized cities, the flood occurrence is expected to increase and the particular weaknesses of the water and sanitation systems will expose vulnerable groups to more risks to water-related and vector-borne diseases.