This literature review deals with the transport and ecological effects of highway run off pollutants with special references to rural environments. Highway run off water contains suspended solids, oxygen-consuming pollutants, nutrients, heavy metals, organic pollutants, microorganisms, Na, Cl, etc. The highway run off fluxes of pollutants are influenced by type of traffic, traffic volume, precipitation regime, road drainage and road surface characteristics, as well as maintenance and operations. Highway run off is transported via gutters, ditches or retention/detention ponds to the ground water or the receiving watercourse. Infiltration, overland flow and spray are other transport routes. References are given to literature on highway run off treatment methods and facilities. The treatment of highway run off water and of waste soil from ditch clearing is discussed from an ecological point of view. The need for further research is identified. (A) For the Swedish version of this report, VTI Rapport 391, please see IRRD 871442.
Samenvatting