Coastal Storms: Should I Evvacuatem and How do I Prepare?/ Using a Novel Method to Map Flood Susceptibility of the Lower Connecticut River Region
Wednesday, October 24, 2018
3:45 p.m. - 4:15 p.m. EDT
CM | 0.50Add to My Log
Towns have made a strong effort, particularly following Storms Irene and Sandy, to provide information on town websites regarding storm preparedness. This presentation is focused on augmenting town information and reaching residents with the importance of evacuating when asked to do so. This project builds on the research findings of Marlon et al. 2015 in which they found:
· 70% of coastal residents surveyed were either unsure or did not think they lived in an evacuation zone (when in fact all those surveyed were in an evacuation zone).
· 74% of coastal residents surveyed had not seen a local evacuation route map.
Given the large number of both residents and transients (vacationers/ weekenders) in Connecticut’s coastal communities, it is imperative to provide accessible, digital evacuation maps with shelter or respite locations. Working with four pilot communities, we have developed an ESRI Story Map to increase awareness of the need to evacuate when requested and provide information on where to go. Using historical photographs from the Hurricane of 1938 to show the extent of damage from a powerful storm hitting the Connecticut coast, we provide information on how and why people should prepare for coastal storms. Numerous resources related to weather and emergency preparedness planning for both people and pets are included.
Awareness of land areas that are currently or will be more prone to flooding in the future due to climatic and non-climatic factors is essential to consider in short- and long-term planning. Additionally, most planning activity related to resilience and climate adaptation focuses on coastal flooding and sea level rise. This study focuses on the Lower Connecticut River Valley Region (LCRVR), within which inland flooding was identified as an area of limited research and where the influence of non-climatic factors on flooding has not been assessed. Flood susceptibility was estimated using a method referred to as logistic regression, which can be used to develop a relationship between several non-climatic flood risk factors and the probability of flooding, the spatial extent of which in the current study was estimated using the 100-year FEMA flood hazard area. Flood risk factors considered included elevation, slope, land shape, distance to water, land cover, vegetation, ground materials, soil type, and percent of paved surface. The LCRVR was first split into three sub-regions (urban, rural, and coastal) and then flood risk factor values were extracted from 4,000 point locations in each sub-region; an equal number of these locations were required to be within and outside of the flood hazard area. Logistic regression was performed and allowed the estimation of coefficients, which express the relative importance of each flood risk factor. It was found that ‘elevation’ and ‘distance to water’ have the most influence on flood susceptibility in the urban and coastal sub-regions, while ‘distance to water’ and ‘ground materials’ dominate in the rural sub-region. It was also found that the contribution of ‘land use’ increases by over 200 percent between the rural and urban regions. The coefficients were finally used to develop a model of flood susceptibility that estimates probabilities of flooding throughout the LCRVR. It was found that several areas classified as “very high risk” (80 – 100%) and “high risk” (60 – 80%) were located outside of the 100-year FEMA flood hazard area and included several types of critical infrastructure that prior to this study were assumed to be safe from the effects of a 100-year flood event.
Jeanne Davies, email@example.com