In urban areas, water is often unable to infiltrate into the soil because excess use of concrete buildings, paved surfaces and impermeable surfaces which are common. As a result, urban runoff flows across rooftops, roadways, sidewalks, urban landscapes, and driveways. This results in runoff pollution which is caused while traveling across the urban environment, acquiring contaminants that affect water quality. The pollutants from urban runoff include plant material, fertilizers, pesticides, automotive and household chemicals, litter, and pet waste.
Urban runoff pollution is also called non-point source (NPS) pollution because it comes from many different sources and the original pollution source is not easily identified. It is important to remember that storm-water collection systems benefit us by quickly moving water from streets into waterways or drainage areas, which can prevent flooding.
The effects of urban runoff are significant. It comes in contact with debris and pollutants as the water flow through the urban environment and into channels and storm drains. It can cause negative effects on natural environments on land and water. Polluted water flows down to the river affecting marine life and while enabling soil erosion and collection of sediments at riparian edges. Water polluted with sediment becomes a nuisance preventing the growth of natural vegetation, biological cycles and disrupting the food chain. As plants die and decay, oxygen is removed from the water. Lowered oxygen levels can lead to the death of aquatic life.
Awareness is key in reducing urban runoff and helping us maintain a better ecology. The best way to manage runoff is to infiltrate as much water as possible, back into the ground. Increasing surface area of permeable spaces is one of the ways we can achieve this. This will help water infiltration faster. Planting tress is also a great way to reduce runoff and soil erosion. Trees are important part of the infrastructure used in storm water runoff management systems. They not only help infiltration but also help treating the runoff. Strategically placed catch basins also help redirecting runoff to infiltration gardens or Bioretention areas helping the process.
Easy and often money-saving steps can be taken to improve the water quality of urban runoff. The most effective way to deal with urban runoff is to avoid generating water pollutants as much as possible and wise use of water outdoors. Storm water management is important for maintain a good functional ecological balance on both land and water.