Many aspects of transportation affect soil, land, and water quality. Traffic tends to compact the soil surface, destroy or severely weaken the vegetative cover, and thus reduce the rate at which rainwater will infiltrate into the soil. Furthermore, increased runoff and aggravated erosion result.
Urban storm water runoff is contaminated with traffic-related pollutants, in particular heavy metals and organic micropollutants. Other transportation effects on water quality include street sweeping , oil and gasoline leaks, and application of salt on roads.
Materials present in transportation network runoff are generated from a variety of sources including:
road
surface degradation
vehicle
lubrication system losses
vehicle
exhaust emissions
load
losses from vehicles
degradation
of vehicle tires
road
surface cleaning
de-icing
compounds
atmospheric
deposition/precipitation
Best management practices can be used to minimize the adverse impacts of urban development on water resources and control stormwater runoff quantity and flooding. To accomplish the objective of constructing urban developments which minimize adverse impacts to water quality and quantity and to sensitive natural landscape features, the Northeastern Illinois Planning Commission has outlined five basic principles:
Promote development
which preserves natural drainage and storage features in order to minimize
adverse changes to the hydrologic characteristics.
View
stormwater runoff as a resource rather than a problem, for example, by
recognizing the potential for stormwater runoff to enhance groundwater
recharge.
Design
stromwater management facilities with mulitple-purpose objectives.
Preserve
and enhance natural features, such as wetlands, streams, lakes and woodlands.
Provide
public education regarding development impacts and innovative stormwater
managmement practices.
