Stormwater runoff

Definition

Stormwater runoff refers to the water that flows over surfaces during and after rainfall events, which does not infiltrate into the ground. This runoff is significantly influenced by urbanization, as impervious surfaces like roads, parking lots, and rooftops prevent water from soaking into the soil, leading to increased volume and speed of runoff. The consequences of stormwater runoff can be profound, contributing to flooding, erosion, and the transport of pollutants into waterways.

5 Must Know Facts For Your Next Test

1. Urbanization leads to a higher proportion of impervious surfaces, drastically increasing the volume and velocity of stormwater runoff compared to natural landscapes.
2. Stormwater runoff can carry various pollutants, including oils, heavy metals, sediment, and nutrients, which can degrade water quality in nearby rivers and lakes.
3. Increased stormwater runoff can exacerbate flooding in urban areas, overwhelming drainage systems and leading to property damage and public safety issues.
4. Management of stormwater runoff is critical for sustainable urban development and often involves implementing green infrastructure solutions like rain gardens and permeable pavements.
5. Regulations such as the Clean Water Act have been established to control stormwater runoff and promote practices that improve water quality in urban settings.

Review Questions

• How does urbanization specifically affect the volume and speed of stormwater runoff?
  • Urbanization impacts stormwater runoff by increasing the amount of impervious surfaces such as roads, parking lots, and buildings. These surfaces prevent water from soaking into the ground, causing more water to flow over land. As a result, the volume of runoff increases significantly during rain events, and the speed at which it travels also rises, leading to potential flooding and erosion issues in urban areas.
• What are some common pollutants found in stormwater runoff and their effects on local waterways?
  • Common pollutants found in stormwater runoff include oils, heavy metals, pesticides, fertilizers, and sediments. These substances can significantly degrade water quality in local rivers and lakes. For instance, excess nutrients from fertilizers can lead to algal blooms that deplete oxygen in water bodies, harming aquatic life. Additionally, heavy metals can accumulate in sediments and pose health risks to both wildlife and humans who rely on these water sources.
• Evaluate the effectiveness of Best Management Practices (BMPs) in mitigating the impacts of stormwater runoff in urban environments.
  • Best Management Practices (BMPs) are crucial for mitigating the adverse effects of stormwater runoff in urban areas. These practices include green infrastructure solutions like bioswales, rain gardens, and permeable pavements that enhance infiltration and reduce runoff volume. BMPs not only help improve water quality by filtering pollutants but also decrease the risk of flooding by managing the rate at which stormwater is released into drainage systems. By effectively integrating these practices into urban planning, communities can foster more resilient environments that better manage stormwater challenges.

Related terms

Impervious surfaces: Surfaces that do not allow water to penetrate, such as concrete, asphalt, and rooftops, leading to increased stormwater runoff.

Water quality: The physical, chemical, and biological characteristics of water, which can be adversely affected by stormwater runoff carrying pollutants.

Best Management Practices (BMPs): Strategies and techniques employed to manage stormwater runoff in order to reduce its impact on the environment and improve water quality.