Special Topics in Environmental Management

Emerging Treatment Stormwater Best Management Practices for Roadways

1. Ecology embankment. Also known as bioslopes, ecology embankments are modified filter strips that contain a soil mix to improve water quality, reduce runoff volume, and reduce erosion frequency. They are easily incorporated into standard fill slopes, are well proven and field tested, are nonproprietary, and largely last the life of the roadway.

2. Permeable friction course. Originally developed as a safety practice to eliminate water on roadways and reduce noise, permeable friction course has evolved into a stormwater BMP as well. It involves placing a layer of permeable asphalt over a conventional system and has been used extensively in Texas with a great reduction in pollution in the stormwater runoff. With a permeable friction course, rain that falls on the friction course drains through the porous layer to the original impervious road course, where the water then drains along the boundary between the two pavement types until the runoff emerges at the edge of the pavement.

3. Geostore. A type of man-made aquifer, this BMP was developed to help MS4 permittees meet the permit requirement to harvest and reuse stormwater. Geostore is cheaper than tank storage and results in fewer water quality problems; however, it does require substantial space and backfill that is permeable.

4. Batch detention. Developed at the University of Texas, this BMP provides batch treatment of stormwater runoff from an extended detention basin. An automated valve and controller are placed on the outlet of a detention basin, which allow water to be retained in the basin. In testing, the batch detention system has substantially better pollutant removal than extended detention basins.

5. Enhanced sweeping. Originally developed for the airport industry to remove rubber from runways, this BMP has not yet been used in the United States. Taylor explained that it most likely not best for widespread application, but it would be great for hot spots. This BMP maintains porous pavement by loosening and removing deep debris through intensive sweeping.

6. Compost-amended slopes. This BMP increases soil runoff-holding capacity by adding 30 percent compost to 12 inches of soil on slopes. Another advantage is a decrease in the need for irrigation.

7. Plate settlers. Taylor explained that the widespread implementation of this BMP is not fast-approaching in the United States. Plate settlers are hydrodynamic devices that are separate flow-through devices designed in concert with inlets and storm sewers to remove litter, oil, sediment, heavy metals, dissolved solids, and nutrients.

Amanda Czepiel, J.D., is a Legal Editor for BLR’s environmental law publications. Ms. Czepiel has over 6 years of experience as an attorney and writer in the field of environmental compliance resources and has published numerous articles on a variety of environmental law topics, including wastewater and NPDES permitting, brownfields and contaminated sites remediation, oil spill prevention, wetlands, and corporate sustainability. Before starting her career in publishing, Ms. Czepiel worked in hospitality consulting and for various non-profit organizations and government agencies in the environmental field. Ms. Czepiel received her law degree from the University of Connecticut School of Law.

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