TY - JOUR
T1 - Assessment of existing roadside swales with engineered filter soil
T2 - I. Characterization and lifetime expectancy
AU - Ingvertsen, Simon Toft
AU - Cederkvist, Karin
AU - Régent, Yoann
AU - Sommer, Harald
AU - Magid, Jakob
AU - Jensen, Marina Bergen
PY - 2012/11
Y1 - 2012/11
N2 - Roadside infiltration swales with well-defined soil mixtures (filter soil) for the enhancement of both infiltration and treatment of stormwater runofffrom roads and parking areas have been common practice in Germany for approximately two decades. Although the systems have proven hydraulically effective, their treatment efficiency and thus lifetime expectancies are not sufficiently documented. The lack of documentation restricts the implementation of new such systems in Germany as well as other countries. This study provides an assessment of eight roadside infiltration swales with filter soil from different locations in Germany that have been operational for 6 to16 yr. The swales were assessed with respect to visual appearance, infiltration rate, soil pH, and soil texture, as well as soil concentration of organic matter, heavy metals (Cd, Cr, Cu, Pb, Zn), and phosphorus. Visually, the swales appeared highly variable with respect to soil color and textural layering as well as composition of plants and soil-dwelling organisms. Three swales still comply with the German design criteria for infiltration rate (10-5 m/s), while the remaining swales have lower, yet acceptable, infiltration rates around 10-6 m/s. Six of the eight studied soils have heavy metal concentrations exceeding the limit value for unpolluted soil. Provided that the systems are able to continuously retain existing and incoming pollutants, our analysis indicates that the soils can remain operational for another 13 to 136 yr if the German limit values for unrestricted usage in open construction works are applied. However, no official guidelines exist for acceptable soil quality in existing infiltration facilities.
AB - Roadside infiltration swales with well-defined soil mixtures (filter soil) for the enhancement of both infiltration and treatment of stormwater runofffrom roads and parking areas have been common practice in Germany for approximately two decades. Although the systems have proven hydraulically effective, their treatment efficiency and thus lifetime expectancies are not sufficiently documented. The lack of documentation restricts the implementation of new such systems in Germany as well as other countries. This study provides an assessment of eight roadside infiltration swales with filter soil from different locations in Germany that have been operational for 6 to16 yr. The swales were assessed with respect to visual appearance, infiltration rate, soil pH, and soil texture, as well as soil concentration of organic matter, heavy metals (Cd, Cr, Cu, Pb, Zn), and phosphorus. Visually, the swales appeared highly variable with respect to soil color and textural layering as well as composition of plants and soil-dwelling organisms. Three swales still comply with the German design criteria for infiltration rate (10-5 m/s), while the remaining swales have lower, yet acceptable, infiltration rates around 10-6 m/s. Six of the eight studied soils have heavy metal concentrations exceeding the limit value for unpolluted soil. Provided that the systems are able to continuously retain existing and incoming pollutants, our analysis indicates that the soils can remain operational for another 13 to 136 yr if the German limit values for unrestricted usage in open construction works are applied. However, no official guidelines exist for acceptable soil quality in existing infiltration facilities.
U2 - 10.2134/jeq2011.0318
DO - 10.2134/jeq2011.0318
M3 - Journal article
C2 - 23128753
SN - 0047-2425
VL - 41
SP - 1960
EP - 1969
JO - Journal of Environmental Quality
JF - Journal of Environmental Quality
IS - 6
ER -