In urban and suburban areas, much of the land surface is covered by buildings, pavement and compacted landscapes. These surfaces do not allow rain and snow melt to soak into the ground which greatly increases the volume and velocity of stormwater runoff. In addition to these habitat-destroying impacts, pollutants from urban runoff include:
Sediment
Oil, grease and toxic chemicals from motor vehicles
Pesticides and nutrients from lawns and gardens
Viruses, bacteria and nutrients from pet waste and failing septic systems
Road salts
Heavy metals from roof shingles, motor vehicles and other sources
Thermal pollution from impervious surfaces such as streets and rooftops