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Rivers Erosion, Weathering, Sediments and Deposits Slide 2 The five major rivers that flow into the Chesapeake Bay are: 1. Susquehanna 2. Potomac (Shenandoah) 3. Rappahannock 4. York 5. James Slide 3 Rivers bring fresh water into the Chesapeake Bay. The Chesapeake Bay is an estuary, so the salt water from the ocean mixes with the fresh water from the rivers. Slide 4 Runoff from the rivers can affect the abiotic factors of the Chesapeake Bay. These are non-living factors, such as water, temperature, soil, light that influence the ecosystem. Slide 5 Running water affects the landscape. Slide 6 Rivers run downhill, and the more steep the ground, the runoff moves faster. Slide 7 Fast water has more energy and creates more weathering and erosion. Slide 8 When the river has more energy, the river is straighter When the river has less energy, the river may become a meandering stream or river. Slide 9 Vocabulary: Erosion vs. Weathering Weathering The chemical or mechanical breaking down of rocks or materials. Erosion Process by which earth material is moved from one area to another by water or wind. Slide 10 Weathering and Erosion is common along river and stream banks throughout the Chesapeake Bay watershed. Slide 11 Bluffs and deep walled valleys Canyons Slide 12 Rivers carry sediment. Sediments are materials such as rock fragments and grains of sand that have been transported by wind, water, or glaciers. Slide 13 1. Dissolved load fine sediment that is dissolved. Slide 14 Sedimentscontinued 2. Suspended load sediment suspended (floating) and transported through the stream. 3. Bed load: larger sediment that does not float. Slide 15 In the Chesapeake Bay, there exists sediment pollution. These sediments include clay, silt, or sand that eventually settle to the bottom. Sediments are natural, but too much creates harmful conditions for the Bays plants and animals. Slide 16 Examples of Sediments Affecting the Bay Smother bottom dwelling animals such as oysters and clams. Slide 17 Examples of Sediments Affecting the Bay Sediments cloud the water, preventing light from getting to the leaves of underwater grasses. (submerged aquatic vegetation), also known as SAV. Slide 18 Turbidity = Water Clarity Suspended sediments block sunlight and increase the turbidity. Slide 19 Sediments can also carry toxic materials, including nutrients, especially containing phosphorus and nitrogen compounds. Slide 20 Agriculture and the Bay Agriculture (farming) in the Chesapeake Bay watershed is the largest factor for introducing fertilizers into the bay. Slide 21 Reducing Sediments can be done by: 1.silt fences capture the sediment around construction sites. Slide 22 Silt fences Slide 23 Reducing Sediments can be done by: 2. Plant trees help slow erosion Slide 24 Forests filter and slowly release sediment from the land. Slide 25 Moving Water Can Erode Banks Trees (Forests) and Vegetation Help Slow Erosion Slide 26 When Europeans first arrived to the Bay region, 95% of watershed were covered in forests. Today, only 58% of the watershed is covered by forests. Slide 27 Reducing Sediments can be done by: 3. No till farming farmers can avoid disturbing the earth Slide 28 No Till Planting Slide 29 New and varied methods are being used to reduce sediment reaching the Bay and other waterways. Slide 30 Other ways of reducing sediments: Reduce roads and parking areas (asphalt) Plant buffers, which allow plants to filter water and trap sediments Slide 31 Rivers carry sediments when the river has enough energy. When the river slows down, the sediment is dropped as deposits. Slide 32 Slide 33 When the river slows down, deposits are created. http://www.fgmorph.com/fg_3_23.php Slide 34 As a stream empties into a body of water such as a lake, gulf, or bay, sediment is deposited forming a delta. Slide 35 When the river is fast moving, the deposit can form an alluvial fan. Slide 36 Streams with many bars and islands separated by river channels are called braded streams. Slide 37 A floodplain is next to a river that is created from river sediment and is periodically flooded. Slide 38 River Notes 38 SusquehannaPotomacRappahannockYork James fresh Estuary abiotic light landscapedownhill faster weatheringerosion straighter meandering stream or river Slide 39 39 rock water load Fine sediment you cant see. Sediment that is floating * muddy water. Larger sediment that does not float. pollution clay conditions plants animal bottom cloud light turbidity toxic phosphorusnitrogenagriculture Slide 40 40 Silt fences Planting trees No till farming deposits loses energy delta alluvial fan river Slide 41 41 When materials are broken down or worn away. Use of force to break apart material Teeth breaking down food / Glaciers Use of chemicals to wear down or break apart. 00-68-14 5-6 Sulfur oxideNitrogen oxide rain chalk Larva / eggs water Erosion Flooding, during hurricane ocean waves Slide 42 ws#9 The Watershed Story Read Story either as a class, small group or independently. Answer questions on ws#9! Collecting as a SUMMATIVE!!! 42 Slide 43 Slide 44 Slide 45 ws#8- Abiotic vs Biotic 45 Turn in this paper to Mrs. Knot!! I will look at your paragraphs!!! Slide 46 Have a wonderful weekend! Enjoy your video.. Bill Nye Watersheds What is a watershed? More Watersheds Bill Nye Water TreatmentWater Treatment Bill Nye - WetlandsWetlands 46 Slide 47 Sources http://en.wikipedia.org/ http://www.owml.vt.edu/aboutowml.htm http://potomacappalachian.org http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html http://www.fgmorph.com