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Watersheds. Water Basics. Water is Made Up of Two Elements Hydrogen Oxygen How can we write “water” in a chemical formula? H 2 O. Watershed. Watershed --all the land that drains into a given body of water, for example a particular stream, river, or lake.
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Water Basics • Water is Made Up of Two Elements • Hydrogen • Oxygen • How can we write “water” in a chemical formula? • H2O
Watershed • Watershed--all the land that drains into a given body of water, for example a particular stream, river, or lake. • the land that water flows across or under on its way to a stream, river or lake
It is a land feature that can be identified by tracing a line along the highest elevations between two areas on a map, often a ridge. • Large watersheds, like the Mississippi River basin contain thousands of smaller watersheds.
Everyone lives in a watershed. • 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 or lake. • Some will eventually end up in the ocean.
Definition • watershed videos
Divides • A divide is the ridge on the ground that separates watersheds. Continental divide for example Watersheds A and B as defined by roof of Arlington House, at Arlington Cemetery
Why Know Your Watershed Address? • Most of you live downstream from someone else. • The way land is used upstream has a direct effect on YOUR WATER! • So if you care about the quality of the water you are drinking, cooking with and showering in you have an interest in knowing where the water has been before it gets to your house.
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.
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.
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.
Salinity • Salinity variations of the Chesapeake • Salinity changes based on depth • Deeper water is saltier, surface water is less salty • Salinity changes based on location • Saltier near the ocean opening • Less salty near the mouths of rivers and the farthest from the ocean opening
Salinity changes with the tide • More salt water enters with high tide • Salt water leaves with low tide • Salinity changes with currents • Natural currents move the salt water • Boats, animals, and people move and mix the salt and fresh water • Salinity changes with wind and storms
Benefits of Estuaries • Habitats for many types of wildlife • Recreation • Fishing • Wetlands filter stormwater runoff, absorb flood waters, and prevent erosion • Shipping ports
Abiotic Features • Non-living features of a particular area • Man-made – buildings, streets, parking lots • Chemical or Geological – rocks, soil types • Physical – weather, temperature, amount of light
Biotic Features • Living features of a particular area • Plants and animals living in an area • Phytoplankton, zooplankton, small fish and animals, larger fish and animals
Problems with health of Estuaries • Too much sediment – not enough light for phytoplankton, ruins habitats of bottom dwellers like oysters • Too many nutrients (from fertilizer) – too much algae, takes away light, rots and uses up oxygen, creates dead zones • Pathogens (disease causing organisms) many from animal wastes • Toxic chemicals, habitat loss, changes in water flow, invasive species
Wetlands • Transition zone between water and dry land • Examples: swamps (trees and water), marsh (grasses and water), bogs • Great nurseries for all kinds of animals because of the many hiding places • All wetlands are wet at least part of the time (standing water), sometimes ground is really soaked and not visibly wet
Tributary • Streams and rivers that eventually flow into a larger water body. • For example, the James River is a tributary of the Chesapeake Bay. • The local tributaries are Cub Run and Bull Run. These flow into the Occoquan River.
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
Groundwater • Water or Precipitation that soaks into the ground • Becomes part of the water table or underground streams
Riparian buffer • Riverside forests and other vegetation • Important for preventing soil erosion, absorbing stormwater, keeping water cool and clean, providing nutrients for living creatures in the area
How we use the land in a watershed affects the water that flows through it. Two Kinds of Water Pollution • Point Source = you can point exactly to where the pollution is coming from. • Non-Point Source = you can not easily identify where the pollution is coming from.
Point Source Pollution • Pollution that comes from an identifiable place or a single source • Example: Leaking sewage pipes, Factories with industrial discharge pipes Straight pipe discharge
Nonpoint Source Pollution • Pollution that does not come from a single source • Examples: Litter, animal waste, fertilizer that washes off lawns Construction erosion
Point Source or Non-Point Source Pollution? • Overflow at a sewage treatment plant? • P • Fertilizer from yards or golf courses? • N • Rainwater running off a parking lot after a storm? • N • Animal manure from a pasture or lawn? • N • Used motor oil from a car whose owner empties it into a storm drain? • P • Old gasoline storage tank leaking gasoline into the groundwater? • P
condensation Water Cycle precipitation condensation precipitation runoff accumulation (storage)
The water that we drink is the same water that was on the Earth 4 billion years ago. Water travels in a cycle, so the water on, above and below the surface of the Earth is always moving. • For example, stormwater flows into a stream which then flows to rivers, to the Chesapeake Bay, and ultimately to the Atlantic Ocean.
Some of the water from streams and rivers is withdrawn and treated at water treatment plants, then sent through pipes to your home. • After the water is used, it flows from your house to a wastewater treatment plant. Once the wastewater is treated, it is released back into local waterways.
How Much StormwaterDoes One Inch of Rain Produce? • When it rains, about 5% of the rain water runs off wooded areas and about 95% of the rain water runs off a parking lot. During a one inch rainstorm . . . 25,800 gallons of water runs off a one-acre parking lot 1,360 gallons of water runs off a one-acre wooded area
Stormwater runoff goes directly into streams, rivers, and the rest of the water supply • Stormwater is not treated in a water treatment facility • Stormwater carries with it anything that is loose on the ground – soil, chemicals, fertilizer, metals, trash, animal waste, oil, gasoline, vehicle fluids, and so forth • These pollutants get into our water supply, affect the plants and animals in the water ecosystems and cost money in lost food, jobs, clean up efforts, and so on
Storm Drainage Systems Curb Inlet Yard Inlet
Asphalt channel Rip-rap (stone) channel
