PA Standards:

 4.1.7.E – Identify factors that contribute to change in natural and human-made systems  4.2.7.A – Explain how water enters, moves through, and leaves a watershed  4.2.7.B – Explain the primary functions of a wetland within a watershed

56. Chp. 2 – Fresh Water

 A river begins with runoff – water from rain or melting snow that flows on the ground surface  Conditions that create more runoff include: heavy rainfall, hard surfaces (rock or pavement), and steep hillsides

57. River Systems

 Made up of  a river and its tributaries (smaller streams that feed it)  Located in  a watershed (land area that drains into the river)  Separated by  a divide (ridges of land between watersheds)

58. PA has 6 watersheds; ours is the Susquehanna Watershed

59. Our watershed drains into the Chesapeake Bay in Maryland

60. Rivers Shape the Land

 Rivers wear away landforms by erosion when fast water carries away soil & rock – fragments  Rivers build new land by deposition of sediments – when slow water dumps soil & rock particles on the bottom

The Grand Canyon was formed over millions of years by erosion

View the animations of erosion and deposition:  Erosion: http://www.classzone.com/books/earth_science/t erc/content/visualizations/es1305/es1305page0 1.cfm?chapter_no=visualization  Deposition: http://www.classzone.com/books/earth_science/t erc/content/visualizations/es0604/es0604page0 1.cfm?chapter_no=visualization

61. Parts of a River:

 Source  where a river begins in the mountains  Headwaters  many small streams that join to start the river; these will be swift flowing waters over steep slopes  Downriver  where the path becomes less steep; the volume of water increases due to tributaries

62. (More River Parts)

 Flood Plain  the river’s path through a broad, flat valley  Mouth  where the river empties into a larger body of water (lake or ocean)  Delta  land built up at the river mouth from deposits of sediment

63. River Flood Control Methods  1. Dams – barriers built to redirect river’s path or store the water in man-made lakes  2. Levees – natural build up of sediments along the bank of the river; often man reinforces a levee with stone or concrete

The Levee System Failed during Hurricane Katrina in New Orleans, Louisiana – 2005.

Breaches occurred on the Mississippi River side and 1,577 deaths resulted.

Video: Flood Damage from Melting Snow  Your text tells of a devastating flood in Fargo, North Dakota in 1997. It happened AGAIN in 2009 as you’ll see in this clip.  http://www.youtube.com/watch?v=medCr0 KITZ0&feature=relmfu

Flood Damage from Heavy Rains  2011 Flood damage in PA was also devastating as show here:  http://www.accuweather.com/blogs/news/s tory/54806/more-photos-from wednesdays-ho.asp

64. Still Water Habitats:

 Ponds  Lakes – bigger than a pond  Reservoirs – a lake that stores water for human use

65. Ponds and Lakes contain animal life of two types:  1) Invertebrates – small animals without any internal bones (they may have a shell)  2) Vertebrates – larger animals with an internal skeleton of bones

66. Wetlands – land covered with shallow water for some or all of the year  Include: marshes, swamps and bogs

67. The Florida Everglades National Park  Instead of draining all of this swamp land, our government now tries to protect this valuable wetland resource



Everglades Wildlife

68. Importance of Wetlands:

 Provide animal habitat for many species (some endangered)  Serve as winter home for migrating birds down from the north  Flood control as they absorb extra runoff (like a sponge)

69. Glaciers can cause erosion

 Huge masses of ice and snow that move slowly over land, carrying rock  Form when years of snow buildup compresses into a block of ice  Large glaciers – called continental glaciers are found only in Greenland and Antarctica covering wide areas of land  Small glaciers – called valley glaciers form on mountainsides and slide down slopes

Glacier Photos

The “Boulder Field” at Hickory Run State Park was formed when melting glaciers left behind tons of rock.

70. Icebergs – frozen fresh water  Form when a glacier reaches the seacoast and pieces break off into the ocean  90% of an iceberg lies beneath the water’s surface making them dangerous to ships

71. Groundwater- another valuable resource  Sand and gravel are full of pores (holes) that make them “permeable”; this means water can pass through this soil.

 Water percolates down until it hits material that is “impermeable”; clay and rock do not let water pass through.

 The “water table” marks the upper edge of ground that is fully saturated with water

72. Below the Water Table:

  The saturated zone (full of water) creates an “aquifer” – an underground water supply to which a well can be drilled