Urban runoff

Urban runoff is a form of surface runoff that is generated by urbanization. It is characterized by the rapid flow of rainwater from roofs, roads, and other man-made surfaces to storm drains, which often lead directly to rivers, lakes, and oceans. This runoff can carry pollutants, sediment, and other materials into these bodies of water, potentially causing significant environmental damage.

Causes of Urban Runoff

Urban runoff is primarily caused by rainfall and snowmelt that occurs on impervious surfaces, such as roads, parking lots, and rooftops. These surfaces prevent water from infiltrating into the ground, leading to increased runoff. Other contributing factors include the removal of vegetation and soil, changes in topography, and the construction of drainage networks and other infrastructure.

Impacts of Urban Runoff

Urban runoff can have a number of negative impacts on the environment and human health. These include:

• Water pollution: Urban runoff can carry a variety of pollutants into bodies of water. These can include heavy metals, pesticides, oil and grease, litter, and fecal coliform bacteria. This pollution can harm aquatic life and make water unsafe for human use.

• Erosion and sedimentation: The increased volume and speed of urban runoff can cause erosion and sedimentation in rivers and streams. This can degrade habitats and harm aquatic life.

• Flooding: Urban runoff can increase the risk of flooding, particularly in areas with inadequate drainage infrastructure.

• Heat island effect: Impervious surfaces can increase the temperature of urban runoff, which can then raise the temperature of receiving bodies of water. This can harm aquatic life and contribute to the heat island effect.

Management of Urban Runoff

There are a number of strategies for managing urban runoff, including:

• Green infrastructure: This includes practices such as rain gardens, green roofs, and permeable pavement, which can absorb and filter runoff.

• Stormwater management: This includes the use of storm drains, detention basins, and other infrastructure to control runoff and prevent flooding.

• Pollution prevention: This includes practices such as street sweeping, litter control, and the proper disposal of hazardous materials.

See Also

• Water cycle
• Water pollution
• Stormwater
• Sustainable urban drainage systems
• Low-impact development (North America)