Great Lakes Communities and Ecosystems
Water Cycle How the cycle works Added human pressures

SURFACE WATER
Lakes, rivers, and streams are the aboveground sources of fresh water for residential, recreational, industrial, and agricultural uses. Water quality is threatened when contaminants--such as sewage, oil, chemicals, fertilizers, and hazardous chemicals--enter the surface water.

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Water Cycle diagram

© 2003 Union of Concerned Scientists Riparian ZonesGreat LakeWetlandsGroundwaterForestsSurface and Subsurface RunoffSurface WaterInfiltrationEvaporationWatershed BoundaryTranspirationPrecipitationCondensation