Rivers Erosion, Weathering, Sediments and Deposits

1. Rivers and Tributaries Rivers Erosion, Weathering, Sediments and Deposits

2. The five major rivers that flow into the Chesapeake Bay are: • Susquehanna • Potomac (Shenandoah) • Rappahannock • York • James

3. Rivers bring freshwater 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.

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.

5. Running water affects the landscape.

6. Rivers run downhill, and the more steep the ground, the runoff moves faster.

7. Fast water has more energy and creates more weathering and erosion.

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.

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.

10. Weathering and Erosion is common along river and stream banks throughout the Chesapeake Bay watershed.

11. Bluffs and deep walled valleys Canyons

12. Rivers carry sediment. Sediments are materials such as rock fragments and grains of sand that have been transported by wind, water, or glaciers.

13. There are different types of sediment, also called the river’s “load.” 1. Dissolved load fine sediment that is dissolved.

14. Sediments…continued 2. Suspended loadsediment suspended (floating) and transported through the stream. 3. Bed load: larger sediment that does not float.

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 Bay’s plants and animals.

16. Examples of Sediments Affecting the Bay Smother bottomdwelling animals such as oysters and clams.

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.

18. Turbidity = Water Clarity Suspended sediments block sunlight and increase the turbidity.

19. Sediments can also carry toxic materials, including nutrients, especially containing phosphorus and nitrogen compounds.

20. Agriculture and the Bay Agriculture (farming) in the Chesapeake Bay watershed is the largest factor for introducing fertilizers into the bay.

21. Reducing Sediments can be done by: • silt fences – capture the sediment around construction sites.

22. Silt fences

23. Reducing Sediments can be done by: 2. Plant trees – help slow erosion

24. Forests filter and slowly release sediment from the land.

25. Moving Water Can Erode BanksTrees (Forests) and Vegetation Help Slow Erosion

26. When Europeans first arrived to the Bay region, 95% of watershed were covered in forests. Today, only58% of the watershed is covered by forests.

27. Reducing Sediments can be done by: 3. No till farming – farmers can avoid disturbing the earth

28. No Till Planting

29. New and varied methods are being used to reduce sediment reaching the Bay and other waterways.

30. Other ways of reducing sediments: Reduce roads and parking areas (asphalt) Plant buffers, which allow plants to filter water and trap sediments

31. Rivers carry sediments when the river has enough energy. When the river slows down, the sediment is dropped as “deposits.”

32. Depositsare loose sediments that build up after water in a river loses energy and cannot carry it any further.

33. When the river slows down, deposits are created. http://www.fgmorph.com/fg_3_23.php

34. As a stream empties into a body of water such as a lake, gulf, or bay, sediment is deposited forming a delta.

35. When the river is fast moving, the deposit can form an alluvial fan.

36. Streams with many bars and islands separated by river channels are called braded streams.

37. A floodplain is next to a river that is created from river sediment and is periodically flooded.

38. River Notes Susquehanna Potomac Rappahannock York James fresh Estuary abiotic light landscape downhill faster weathering erosion straighter meandering stream or river

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 light cloud turbidity toxic phosphorus nitrogen agriculture

40. Silt fences Planting trees No till farming deposits loses energy alluvial delta fan river

41. ws#9 – The Watershed Story • Read Story either as a class, small group or independently. • Answer questions on ws#9! • Collecting as a SUMMATIVE!!!

44. ws#8- Abiotic vs Biotic Turn in this paper to Mrs. Knot!! I will look at your paragraphs!!!

45. Have a wonderful weekend! • Enjoy your video….. • Bill Nye – Watersheds • What is a watershed? • More Watersheds • Bill Nye – Water Treatment • Bill Nye - Wetlands

46. 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