EPA researchers, in collaboration with the DHS’s Science and Technology Directorate, have developed stormwater models to help state and local emergency stormwater stakeholders predict and mitigate the transport of biological agents and radionuclides. These models were later used in a series of workshops to bring about awareness, training, and to create a checklist resource.

According to EPA, stormwater can transport pollutants, such as heavy metals, pathogens, and nutrients, which threaten the quality of rivers, lakes, and oceans. However, many stormwater operators have not considered or planned for the difficulties in predicting and mitigating transport of biological agents (e.g., anthrax-causing bacterium) or long-lasting radionuclides (e.g., cesium-137) that may result from a terrorist attack. Using EPA’s Stormwater Management Model (SWMM), EPA researchers  developed models of three cities - Detroit, Buffalo, New York, and a U.S. Coast Guard Base in Elizabeth City, North Carolina - to track and quantify washoff of deposited Cesium-137 following a mock explosion of a radiological dispersal device.

A radiological dispersal device, often referred to as a “dirty bomb”, is a combination of an explosive, such as dynamite, with a radioactive powder. This type of device can have a broad range of impacts depending on the size of the explosion, the type of radioactive material used, how it was dispersed, and the weather conditions at the time of dispersal. These models identified how contamination could be transported and discharged throughout the locations following a rain event. This information could be used by emergency response teams to identify the most impacted portions of infrastructure and inform decisions to prioritize cleanup, monitoring and treatment, and restrict entry points. Read more at EPA.