ASSESSMENT OF VULNERABILITY OF COASTAL COMMUNITIES TO SEA LEVEL RISE: A CASE STUDY OF BONNY COMMUNITIES IN RIVERS STATE, NIGERIA.

Abstract

According to United Nation Environmental Program document of 2010, Climate Change is one of the major challenges of our time; it adds considerable stress to our societies and to the environment. From shifting weather patterns that threaten food production, to rising sea levels that increases the risk of catastrophic flooding, the impacts of climate change are global in scope and unprecedented in scale. This study focuses on the assessment of vulnerability of coastal communities to sea level rise resulting from natural and anthropogenic processes. A Landsat satellite image of 2005 of the study area was classified, land cover map was generated after which four classes of land cover was vectorized namely: Built-up, Light forest, Mangrove forest and water body. Elevation data was generated from the Shuttle Radar Topographic Mission (SRTM) of 2008. This was used to create a slope map of the study area. Then, proximity map was generated using Euclidean distance from the water body. The three parameters; land cover, Slope and Proximity maps were weighted and overlaid to determine the vulnerability levels of the study area to coastal flooding. The study reveals a predominant slope of 0 – 0.5 and elevation of 0 – 5m above mean sea level. The tide analysis reveals two set of high and low water level per day with a significant diurnal inequality. A highest tide level of 2.6m and lowest tide level of 0.10m was observed. This suggests a likely incursion of water into areas of elevation 0 – 2m above mean sea level. The study covers a total area of 35,408Hectares, 5,901Hectares (16.7%) of the study areas are highly vulnerable, 20,851Hectares (58.9%) are moderately vulnerable, 8,296(23.4%) are low vulnerable areas whereas just 360Hectares (1.0%) are non vulnerable areas of the study. The study suggested that State and Local government should collaborate to establish sustained agencies, policies and initiatives for sea level rise adaptation.