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Presentation on theme: "Watersheds."— Presentation transcript:

1 Watersheds

2 Definition Watershed--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

3 Why Know Your Watershed Address?
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.

4 Watersheds of US

5 Chesapeake Bay Watershed
Watershed shown in white. Surrounding area in pink.

6 Chesapeake Bay Watershed
The 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.

7 Watersheds of Virginia

8 Potomac-Shenandoah Watershed

9 Cub Run Watershed

10 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.

11 Estuary An 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.

12 Chesapeake Bay Estuary
Chesapeake 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.

13 Benefits of Estuaries Habitats for many types of wildlife Recreation
Fishing Wetlands filter storm water runoff, absorb flood waters, and prevent erosion Shipping ports


15 Salinity Saltiness of water
Closer to the ocean, the more salty the water Closer to the rivers, the less salty the water Deeper 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

16 Abiotic vs. Biotic Features
Abiotic 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

17 Runoff Storm water runoff Precipitation that does not evaporate or
soak into the ground It pools or puddles and travels downhill into streams or other bodies of water

18 Groundwater Water or Precipitation that soaks into the ground
Becomes part of the water table or underground streams

19 2 Types of Pollution Point Source Pollution Nonpoint Source Pollution
Pollution 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

20 Storm Drainage Systems
Curb Inlet Yard Inlet

21 Concrete Channels Concrete Channels

22 Grass swales Grass swales, zig zag swales or straight

23 Riprap and asphalt channels
Riprap (stone) channel Asphalt channel

24 Outfalls Outfalls

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