DefinitionWatershed--all the

land that drains into a given body of water, for example a particular stream, river, or lake.

Large watersheds, like the Mississippi River basin contain thousands of smaller watersheds.

watershed videos

Everyone lives in a watershed: quality of the water you are drinking, cooking with and showering in are affected by the watershed

You have an interest in knowing where the water has been before it gets to your house..

Think about where the water goes when it rains on your house.Runs off your roof and into guttering.Runs onto the driveway or grass.Some is absorbed but some runs off.

Runs off surfaces until it reaches a nearby creek/stream.

Flows to a larger body of water such as a river, lake, and ocean.

Watersheds of US

Chesapeake Bay Watershed

Watershed shown in white. Surrounding area in pink.

Chesapeake Bay WatershedThe Chesapeake Bay watershed stretches

across more than 64,000 square miles, encompassing parts of six states — Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia — and the entire District of Columbia.

The Chesapeake's land-to-water ratio (14:1) is the largest of any coastal water body in the world. This is why our actions on the land have such a significant influence on the health of the Bay.

Watersheds of Virginia

Potomac-Shenandoah Watershed

Cub Run Watershed

Tributary

Streams and rivers that eventually flow into a larger water body.

The local tributaries are Cub Run and Bull Run. These flow into the Occoquan River.

EstuaryAn estuary is a partially enclosed body of

water where fresh water from streams and rivers mixes with salt water from the ocean.

Brackish water - the mix of salt and fresh water in an estuary

Estuaries are among the most productive environments on earth, creating organic matter and providing a variety of habitats that support diverse animal and plant communities.

Chesapeake Bay EstuaryChesapeake Bay is the largest of 130

estuaries in the United States. About half of the Chesapeake's water volume

comes from salt water from the Atlantic Ocean.

The other half drains into the Bay from its enormous 64,000-square-mile watershed.

Because of this mix of fresh and salt water, the Bay's salinity gradually increases as you move from north to south.

Benefits of Estuaries

Habitats for many types of wildlifeRecreationFishingWetlands filter storm water runoff, absorb

flood waters, and prevent erosionShipping ports

SalinitySaltiness of waterCloser to the ocean, the more salty the waterCloser to the rivers, the less salty the waterDeeper in the estuary, the saltier the water

(salt water is denser than fresh water)Tides, currents, wind, storms, boats and

animals swimming can all help to change the salinity

Abiotic vs. Biotic FeaturesAbiotic Features Biotic Features

Non-living features of a particular area

Man-made – buildings, streets, parking lots

Chemical or Geological – rocks, soil types

Physical – weather, temperature

Living features of a particular area

Plants and animals living in an area

Runoff

Storm water runoffPrecipitation that does not evaporate or soak into the groundIt pools or puddles and travels downhill into

streams or other bodies of water

Groundwater

Water or Precipitation that soaks into the ground

Becomes part of the water table or underground streams

2 Types of PollutionPoint Source Pollution Nonpoint Source

PollutionPollution that comes

from an identifiable place or a single source

Example: Leaking sewage pipes, Factories with industrial discharge pipes

Pollution that does not come from a single source

Examples: Litter, animal waste, fertilizer that washes off lawns

Storm Drainage SystemsCurb Inlet Yard Inlet

Concrete ChannelsConcrete Channels

Grass swalesGrass swales, zig zag swales or straight

Riprap and asphalt channelsRiprap (stone) channel Asphalt channel

OutfallsOutfalls