GIS-Based Decision Support Tools to Plan for and Respond to Radiological Incidents Across the Response Timeline - 21052

Management of waste from wide-area radiological incidents will be complicated by several major issues: 1) the potentially enormous quantities of solid and aqueous waste, lightly contaminated with one or more radionuclides, that will need to be properly managed; 2) the profound impact that decontamination/demolition strategies will have on the quantity and characteristics of the waste; and 3) the movement of contamination from its initial point of deposition, due to precipitation, vehicular movement, decontamination activities and other human activities. These issues present decision-makers with challenges that follow the incident from the point of pre-incident planning, through the incident itself, and during the longer-term cleanup and monitoring operations. EPA has been working on the development of decision support tools to aid decision-makers' ability to manage the various complexities of a wide-area response using a system-of-systems approach, where decisions are coupled. These tools utilize Geographic Information System (GIS) approaches to develop decontamination strategies based on publicly available infrastructure data within the US and an adaptation of EPA's Stormwater Management Model (SWMM) to model the spread of radionuclides over time as a result of precipitation events. This paper will focus on the application of three tools to support decision makers' needs during such an incident. The first tool is the Waste Estimation Support Tool (WEST), designed for characterizing and quantifying biological and radiological waste that may be generated from decontamination efforts. WEST combines GIS-based analysis of externally-supplied plume data, building infrastructure databases of derived from the Federal Emergency Management Agency's (FEMA's) Hazus tool, and satellite imagery surface recognition algorithms to combine the composition and square footage of buildings in the plume with estimates of materials between buildings in the plume. The resulting GIS data files are then imported into a Microsoft Access database application, where they are combined with information about the nature and concentration of contaminants, and then subjected to decontamination strategies for different contaminated surfaces. The tool provides estimates of the type and quantities of potential wastes resulting from simulated decontamination and/or demolition activities and includes estimates of the remaining contamination levels, including residual contamination, contained within each waste stream. Estimates are presented at several levels of detail, allowing users to obtain needed data at the desired resolution, including estimates for the total affected area, estimates by contamination zone, estimates by decontamination method(s), and estimates by building type (occupancy classification). The second tool to address concerns associated with movement of contamination after the initial release is an adaptation of the EPA's Stormwater Management Model (SWMM) to model the spread of chemical, biological, or radiological (CBR) agents over time as a result of precipitation events. EPA SWMM is a public domain hydrologic and hydraulic model that has been used extensively in the US and throughout the world to simulate stormwater runoff quantity and quality over both single events and extended time frames. The additional capabilities that have been added by the EPA team address the tracking of contamination by expanding the SWMM application programming interface (API) and its Python wrapper, PySWMM. The EPA Weather Tool is an additional Python application that can be used to acquire either historical or forecasted precipitation data that is formatted to drive EPA SWMM simulations. Combining these tools allows new maps of pollutant loading to be generated over time, which are useful for informing other aspects of remediation efforts such as developing sampling and waste management plans. Although these tools are not currently integrated at the software level, it is possible to combine their usage to include contaminant transport considerations, developing cleanup strategies that can adapt to changing situations on the ground. This paper describes a case study where these tools were used in conjunction to examine the effects of contaminant spread after a significant precipitation event. (authors)