Impervious Surfaces

Definition

Impervious surfaces are those that do not allow water to penetrate through them, leading to increased surface runoff and reduced groundwater recharge. Common examples include asphalt, concrete, and rooftops, which can significantly alter natural hydrological processes by increasing the speed and volume of runoff into drainage systems and water bodies. This alteration can have various implications for drainage basin characteristics, land use, and approaches like green infrastructure and low impact development.

5 Must Know Facts For Your Next Test

1. Impervious surfaces increase the volume and speed of stormwater runoff, which can lead to flooding and erosion in nearby streams and rivers.
2. The presence of impervious surfaces in a drainage basin can significantly reduce groundwater recharge, impacting local aquifers and water supply.
3. Areas with high percentages of impervious surfaces often face poorer water quality due to pollutants being washed directly into water bodies without natural filtration.
4. Effective management of impervious surfaces is essential for sustainable urban planning and development, often necessitating the integration of green infrastructure solutions.
5. Low impact development strategies aim to minimize the effects of impervious surfaces by utilizing techniques that promote infiltration, such as green roofs and bioswales.

Review Questions

• How do impervious surfaces influence stormwater runoff patterns in a drainage basin?
  • Impervious surfaces significantly alter stormwater runoff patterns by preventing water from infiltrating the ground. This leads to increased volume and velocity of runoff during rain events, causing rapid surges in nearby waterways. As a result, drainage basins can experience heightened flooding risks and erosion due to the inability of water to be absorbed into the soil.
• Evaluate the impact of urbanization on the prevalence of impervious surfaces and its implications for local hydrology.
  • Urbanization typically increases the prevalence of impervious surfaces as natural landscapes are replaced with buildings, roads, and other constructions. This change disrupts the local hydrology by reducing natural water infiltration and increasing stormwater runoff. Consequently, urban areas face challenges such as flooding, compromised water quality, and diminished groundwater resources, necessitating innovative management practices.
• Propose a strategy that utilizes green infrastructure to mitigate the negative effects of impervious surfaces on local waterways.
  • One effective strategy is implementing permeable pavements in urban areas. By replacing traditional impervious materials with permeable options, rainwater can infiltrate into the ground rather than running off immediately. Additionally, integrating green roofs and bioretention areas can further enhance this approach by allowing for natural filtration processes. This combination not only reduces stormwater runoff but also improves water quality in local waterways while promoting groundwater recharge.

Related terms

Stormwater Runoff: Water that flows over impervious surfaces during and after rain events, contributing to flooding and water quality issues.

Permeable Pavement: A type of pavement designed to allow water to infiltrate through its surface, helping reduce runoff and promote groundwater recharge.

Urban Heat Island Effect: A phenomenon where urban areas experience higher temperatures than their rural surroundings, often due to extensive impervious surfaces absorbing and retaining heat.