Carly Bednarski

Project title: Who is Most Impacted? A GIS Cumulative Impacts Analysis on Chemical Waste Hazards, Floodplains, and Sea Level Rise in King County, WA

Degree: MS (Thesis) | Program: Environmental Health (EH) | Project type: Thesis/Dissertation
Completed in: 2022 | Faculty advisor: Tania M Busch Isaksen


Despite the Washington State Environmental Health Disparities Map and the Duwamish Valley Cumulative Health Impacts Analysis assessments being resources for communities to access environmental threats and social vulnerabilities, there is no single map that includes all factors associated with potential chemical mobilization and flood risks. These factors include sites of possible chemical mobilization, floodplain zones, sea level rise, and incorporating community demographics, that when combined, illustrate a more complete picture of communities’ potential cumulative impacts. This study produced three cumulative impact maps using the California Environmental Protection Agency (Cal/EPA) Environmental Justice Action Plan screening methodology in the Environmental Systems Research Institute (ESRI) Aeronautical Reconnaissance Coverage Geographic Information System (ArcGIS) Pro application software. The first cumulative impacts map ranked communities’ potential impacts by considering chemical waste hazards along with socioeconomic and sensitive population factors, by census tract. The second map factored in the 100-year floodplain, while the third map included sea level rise. The comparison of the three cumulative impacts maps showed how impacts changed for communities based on incorporating different environmental threats, demonstrating the effects these environmental changes would have on present-day communities. Current demographic data was used in all three calculations to apply future scenario events to present-day communities, invoking the need for policy changes or mitigation strategies present-day rather than in the future when it may be too late. Secondary data from the Department of Ecology, the Washington State Department of Health Washington Tracking Network, the Washington State Department of Health Environmental Health Disparities Index, and the National Oceanic and Atmospheric Association (NOAA) were used to perform all analyses and create all maps. Communities may be unaware of their current or future flood potential as well as chemical waste hazards that are within close proximity to them. Understanding the impact climate change will have on sea level rise and incorporating that information into the cumulative impacts maps is vital as it changes communities’ environmental threats. Policy decisions can then be based on these cumulative impacts maps, such as developing more targeted mitigation strategies to diminish consequences from future flood risk or chemical mobilization.