Roads and protection of water resources from pollution

Road drainage systems have the task of collecting and draining, in a controlled manner, storm water runoff from the road surfaces during rain events. The main goal is to increase traffic safety, by reducing surface water flow influence on the traffic. The main factors influencing the water retention on the road surface are: transverse and longitudinal slopes of the carriageway, the distance between the drains, the intensity of the rain and the roughness of the pavement surface. In addition to increasing the safety of traffic in rain conditions, in the recent times the environmental protection objectives, primarily the protection of water resources, are required. Research results indicates that numerous and diverse pollutants originating from vehicular traffic are accumulated on road surfaces and adjacent terrain. During the rain events surface runoff is generated which detaches accumulated pollutants from the road surface and carry them downstream with the runoff. Tasks of contemporary road drainage systems also include controlled collection and discharge of contaminated runoff from roads, including, water retention and adequate treatment before discharge into recipient if necessary. The required quality of the water that is discharged from the roadway to the recipient depends on the local conditions and characteristics of water recipient. A special problem can be accidental pollution, and it requires adequate organizational and technical emergency response measures. The paper presents an overview of the pollution problems related to road runoff and the contemporary ways of solving this problem. It is pointed out that the road route, the geometric elements of the route and the type of pavement surface are of great importance for the road drainage and the protection of water resources, so it is necessary to take care of these aspects during road planning and design.