Impacts of Stormwater

Stormwater has an important impact on the quality of water, public health and the environment. Although companies and municipalities are careful not to dump hazardous chemicals into public waterways or the sea, harmful products often contaminate precipitation which falls in urban areas. Chemicals present in dirt, trash, or air pollution can become part of stormwater which falls in populated ares. Snow or rain which has interacted with dirty city environments runs to the sea or other local bodies of water, impacting both aquatic and human life.

Impact on Water Quality

• Contaminants present in stormwater significantly degrade water quality and are often harmful to life both in water and on land. Chemical contaminants often include cadmium, chromium, lead and mercury; scientists have long established these metals as health hazards. If stormwater runoff leads into a body of water used as a drinking supply, these chemicals could be imbibed by people, potentially causing serious health problems. Stormwater could also carry pathogens such as bacteria, viruses, or parasites. Of these, bacteria are the most common and the most likely to cause illness. Documented health problems caused by stormwater include fevers, chills, vomitting, painful ear discharges, and heavy metal poisoning.

Impact on Water Life

• Since stormwater introduces exotic chemicals and pathogens to a water body, it has a measurable impact on life there. Stormwater is typically slightly warmer than the body of water it runs off into, potentially heating this body by several degrees. Species of fish or underwater plant life which are sensitive to temperature could find their ecosystem become inhospitable. Habitats can also be destroyed by the introduction of sediment dissolved in the stormwater. Excess sediment decreases the visibility of the water and can block small underwater passageways over time.

Impact on Human Life

• Stormwater runoff near public beaches can introduce health hazards

  When stormwater impacts water born life, it can have a profound effect on human life as well. Contaminants and pathogens introduced by stormwater to water near fisheries or drinking supplies can easily find their way into people who could potentially suffer from disease or heavy metal poisoning. A study in California in 1996 found that people swimming within 100 yards on stormwater runoff were far more likely to develop chills, ear disorders, fevers, and a host of other undesirable medical conditions.

Economic Impacts of Stormwater

• The government has passed Clean Water Acts which recognize stormwater as a source of pollution for important bodies of water. These Acts require municipalities and commercial ventures to identify and mitigate the impact of stormwater on the environment. Most of these requirements introduce additional costs to consumers and taxpayers. Stormwater runoff negatively impacts property values by reducing the quality of the local environment. Sediment from stormwater needs to be continually dredged to keep rivers and streams clear. While necessary, these actions cost millions of dollars every year.