What are typical modifications to the landscape in the urban environment?
• Sealing off by buildings, parking lots, roads, sidewalks, driveways and much more. • Flood water control structures from storm sewer drainage to channelization to dams. • Excavation of building pads with associated retaining walls. • Emplacement of fill dirt. • Building of conduits in the ground (water, sewage, gas, electrical), and associated disturbance of ground. What are point sources of contamination in the urban environment? Sources of contamination are separated into point and non-point sources. Point sources have an easily identifiable source of limited area. Non-point sources are introduced into the environment from multiple outlets distributed over a wide area. examples of non-point sources in the city include run-off from chemically treated lawns, or salt from snow-ice removal operations. • Underground storage tanks (every gas station). • Dry Cleaners. • Garages (if use significant amount of degreasers). • Chemical storage sites. • Coal gasification plants. • Foundaries, s
