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What Causes Stormwater?

Stormwater comes from rain or melting snow that does not get absorbed by the ground. Instead, it is funneled through paved areas, parking lots or paved streets, collecting pollutants along the way. This can become a major concern if the water is allowed to flow into local water sources like streams or lakes. Stormwater can occur whenever there is a heavy rain or snow melting, but the major concern is what that water collects and where it goes.

  1. Weather

    • When heavy rains occur, not all the water is absorbed by the ground. Likewise, when a large amount of snow has accumulated and begins to melt, not all the water is absorbed. This leads to water flowing over paved surfaces to lower areas. Often, this runoff will flow into lakes or streams nearby and is usually left untreated. This will drag any pollutants the water picks up into the local water sources.

    Human Watering

    • Not only can runoff come from the weather but also from human's activities. Watering the lawn, washing cars and outdoor watering activities can also lead to water draining into local lakes or streams. Humans can greatly impact the water quality this way and by adding more pollutants to the environment. Pesticides, fertilizers, pet waste, salt and oil from vehicles can all cause environmental damage. In many developed areas, polluted stormwater has become a major environmental concern.

    Types of Pollution

    • Stormwater pollution can come in various forms. It comes from trash and littering as plastic or paper garbage find its way into water sources. Chemical pollution comes from fertilizers and oil. Construction projects can cause soil pollution, which in turn will pollute water sources and the sediment is collected and transported by heavy rain waters. There are also many natural pollutants, such as animal waste, leaves and lawn clippings, including any lawn additives such as fertilizers, pesticides, and herbicides.

    Management

    • Polluted stormwater can be environmentally damaging to the wildlife and local communities. It makes water treatment for local drinking water sources more expensive. Many of the waste chemicals can be dangerous for marine life. Fertilizers can cause too much algae to grow which takes up more oxygen, and can damage fish gills or skin. Runoff is difficult to control and requires building reservoirs to contain polluted stormwater. However, pollution prevention is more manageable and negates many of the concerns about stormwater.

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