key term - Impervious Surfaces

Definition

Impervious surfaces are materials that do not allow water to infiltrate or pass through them, leading to increased surface runoff during rainfall. These surfaces include asphalt, concrete, and other hard materials typically found in urban environments. Their presence significantly alters the natural hydrology and water cycle by reducing groundwater recharge and increasing the volume and velocity of stormwater runoff.

5 Must Know Facts For Your Next Test

1. Impervious surfaces cover a significant portion of urban areas, often exceeding 70% in densely populated regions, which greatly impacts local hydrology.
2. The increase in impervious surfaces is directly linked to urbanization, which alters natural drainage patterns and increases the risk of flooding.
3. Stormwater management practices often focus on mitigating the effects of impervious surfaces by implementing green infrastructure solutions.
4. Impervious surfaces can lead to higher pollutant loads in nearby water bodies since rainwater runoff can carry oils, heavy metals, and sediments into waterways.
5. The reduction of impervious surfaces through urban planning strategies can enhance groundwater recharge and improve overall water quality.

Review Questions

• How do impervious surfaces affect local hydrology and what are some consequences of their prevalence in urban environments?
  • Impervious surfaces significantly disrupt local hydrology by preventing water infiltration into the ground, leading to increased surface runoff. This change can result in flooding, erosion, and degraded water quality as pollutants accumulate in stormwater runoff. The alteration of natural drainage patterns further exacerbates these issues, highlighting the need for effective stormwater management strategies.
• What are some effective strategies that urban planners can implement to mitigate the impacts of impervious surfaces?
  • Urban planners can implement several strategies to mitigate the impacts of impervious surfaces, such as integrating green infrastructure solutions like bioswales, rain gardens, and permeable pavements. These solutions promote water infiltration and reduce runoff while enhancing the aesthetics and ecological value of urban areas. Additionally, zoning regulations can encourage the preservation of green spaces and limit the extent of impervious surface development.
• Evaluate the relationship between impervious surfaces and the Urban Heat Island Effect, and propose potential solutions to address this issue.
  • Impervious surfaces contribute to the Urban Heat Island Effect by absorbing and retaining heat more than natural landscapes, resulting in higher temperatures in urban areas. This phenomenon can worsen air quality and increase energy consumption for cooling. To combat this effect, cities can promote urban greening initiatives such as planting trees, creating green roofs, and implementing cool pavements that reflect rather than absorb heat, ultimately enhancing urban livability.

Related terms

Stormwater Runoff: Water from precipitation that flows over impervious surfaces, which can lead to flooding and water quality issues as it collects pollutants before entering waterways.

Permeable Pavement:

A type of pavement designed to allow water to infiltrate through its surface, reducing runoff and promoting groundwater recharge.

Urban Heat Island Effect: A phenomenon where urban areas experience higher temperatures than their rural surroundings due to the prevalence of impervious surfaces and reduced vegetation.