Impervious Surface

{
  "id": "MLC-T-ENV-013907",
  "term": "Impervious Surface",
  "field": "Environment",
  "definition": "1. A material that does not allow, or allows only with great difficulty, the infiltration of water.\n\n2. Low-permeability material such as asphalt or concrete. Common impervious areas include, but are not limited to, roads, rooftops, walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving, or other surfaces which similarly impede the natural infiltration of storm water.\n\n3. A hard surface area that either prevents or retards the entry of water into the soil mantle or causes water to run off the surface in greater quantities or at an increased rate of flow. Common impervious surfaces include rooftops, walkways, patios, driveways, parking lots, storage areas, concrete or asphalt paving, and gravel roads. [EPA Guidance for Federal Land Management in the Chesapeake Bay Watershed Glossary at http://www.epa.gov/owow_keep/NPS/chesbay502/pdf/chesbay_glossary.pdf]\n\n4. Does not allow stormwater to drain into the soil below. Some examples include concrete sidewalks, driveways and heavily compacted urban soils. Because these surfaces cover the soil, they increase stormwater runoff and should be replaced with more permeable surfaces such as porous pavers, porous asphalt or turf.\n\n5. A hardened surface or area that does not allow water to pass through. For example, roads, rooftops, driveways, sidewalks, pools, patios and parking lots are all impervious surfaces.\n\n6. Impervious surfaces are surfaces that allow little or no stormwater infiltration into the ground. Other than exposed natural rock croppings, impervious surfaces are completely human-created and are an unnatural part of most ecosystems. Impervious surfaces are the main contributor to excess stormwater runoff that would otherwise have been retained on site in natural forests or meadows. Everything that falls on an impervious surface (pollution, trash, animal waste, chemicals, oils, sediment, etc.) washes off of those surfaces during rain events, often on a direct path to local streams or water bodies. Examples of impervious surfaces: Streets, roofs, parking lots, most patios, walkways, or anything else that does not allow water to flow through and into the ground (asphalt, concrete, plastics).\n\n7. A hard surface area that either prevents or slows the entry of water into the soil mantle or causes water to run off the surface in greater quantities or at an increased rate of flow, which can potentially contribute to flooding and transport pollutants into lakes and streams. Common impervious surfaces include rooftops, walkways, patios, driveways, parking lots, storage areas, concrete or asphalt paving, and gravel roads.",
  "subject": "General environmental",
  "references": [
    "Watershed Protection Glossary",
    "EPA Stormwater Discharges from Developed Sites; Glossary from Owner/Developer Long Questionnaire; 4/16/2010 DRAFT VERSION Quoted on NAHB website",
    "EPA Report on the Environment Glossary at http://www.epa.gov/ncea/roe/glossary.htm",
    "Office of the President Council on Environmental Quality Guidance for Federal Agencies on Sustainable Practices for Designed Landscapes at https://www.whitehouse.gov/sites/default/files/microsites/ceq/recommendations_on_sustainable_landscaping_practices.pdf",
    "Chesapeake Bay Program Glossary",
    "Impervious Surface",
    "Report on the Environment (ROE) Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/impervious-surface/"
}