When roads want to be dams: looking to dam safety to regulate transportation embankments

The potential for failure processes developing in transportation embankments temporarily impounding water has not been a common consideration in the design and management of these structures. However, changes in water elevations due to land development and climate change have prompted concern about impoundment on seepage rates and overall stability of the constructed embankments. This study was conducted to examine how different aspects of dam safety can be incorporated in transportation embankment management. Evolving issues pertaining to water impoundment were investigated, transportation and dam embankments were compared, current US Mid-Atlantic state policies were summarized, and numerical modeling of seepage and slope stability was conducted to understand how example transportation embankments behave under various water impoundment scenarios. Performance assessment of granular materials commonly used in transportation embankments indicates their ability to withstand piping erosion but demonstrate poor slope stability during rapid drawdown. Recommendations are provided on prioritizing evaluations of transportation embankments. Results demonstrate the need for infrastructure inventories and hydrologic research on this topic.