Land-intensive best management practices (BMPs), such as bioretention basins and dry detention basins, have been installed by NCDOT in high-value water supply and nutrient sensitive watersheds as part of the agency¿s statewide NPDES permit. These BMPs often require additional and costly right-of-ways (ROW) and would most likely saddle NCDOT with long-term maintenance costs. Recently, NCDOT proposed that asphalt porous friction course (asphalt-PFC) can be a viable BMP option, which could provide multiple cost savings in design, installation, and maintenance. Asphalt-PFC can be easily integrated within the linear environment of the roadway system and acts to prevent pollutants from being generated in storm water. Additionally, asphalt-PFC would also improve motorist safety during storm events.
A research team from the University of North Carolina at Charlotte (UNC Charlotte) proposes to initiate a 2.5-year study in order to assist NCDOT to evaluate such a design-related BMP that could be shown to be effective at reducing pollutant loads from roadway runoff. Goals of this proposed project are as follows:To document the types and locations of existing asphalt-PFC in North Carolina and perform literature review of the effectiveness of asphalt-PFC as a viable BMP,To perform a life expectancy analysis and cost comparisons of asphalt-PFC with conventional or concrete highways. Other types of asphalt-rubber and polymer-asphalt open graded fraction course surfaces(Anderson, 1987) may exist in the state and, if so, we will include these types of roadways for evaluationTo conduct a field monitoring study to quantify the pollutant loads (TSS, TN, TP, NO3-N, NH4-N, PO4-P, DOC) from NC asphalt-PFC roadways in comparison to conventional roadway surfaces, andTo assess the potential of integrating asphalt-PFC with roadway ROW vegetation coverage as a sequential treatment train for roadway runoff control.
