Integrated tire wear buildup and rainfall-runoff model to simulate tire wear particles in stormwater

This paper presents an approach to integrate tire wear buildup and rainfall-runoff models to simulate tire wear buildup on road surfaces and its subsequent transport in stormwater runoff events. To do so, a buildup model is presented based on vehicle kilometers traveled, vehicle type, vehicle speed, and road roughness within a watershed. This buildup model was integrated into an EPA SWMM model that simulated the runoff of tire wear particles in twelve watersheds in the San Francisco, CA bay area. Results demonstrate that tire wear particle buildup within the watersheds ranged between 0.4 and 0.51 (kg/km²) per hour. Applied to the SWMM model, total event mean tire wear concentrations ranged between 0.5 and 67 μg/L. These concentrations were linearly correlated to depth-integrated samples collected at the outlet of each of the watersheds (R² = 0.66). The proposed modeling approach can ultimately be applied to create solutions to an emerging stormwater contaminant.