Impervious Surface Cover: Non-Paved Areas

A special algorithm has been applied to the Landsat 7 image to illuminate the changes in low-density residential land use which exemplify sprawl. There is a link between impervious surfaces within a watershed, (here we see a subset of the Chesapeake Bay watershed area) and the water quality within the watershed. In general, once 10-15 % of an area is covered by impervious surfaces, increased sediments and chemical pollutants in runoff have a measurable effect on water quality. When 15-25% of a watershed is paved or impervious to drainage, increased runoff leads to reduced oxygen levels and impaired stream life. When more then 25% of surfaces are paved, many types of stream life die from the concentrated runoff and sediments. Red represents high concentrations of impervious surfaces. Blue represents moderate concentrations and green represents low concentrations of impervious surfaces. Educational levels: Undergraduate lower division, Undergraduate upper division, Graduate or professional