GEOGRAPHY 12:
Download
1 / 56

All part of the hydrologic cycle - PowerPoint PPT Presentation


  • 92 Views
  • Uploaded on

GEOGRAPHY 12: RIVER FORMATIONS http://webs.cmich.edu/resgi/links.asp?mc=Other%20Resource%20Links&cad=Earth%20Science%20Animations&to=257&tod=River%20Animations. All part of the hydrologic cycle. http://polaris.umuc.edu/cvu/envm/hydro/hydro.html `.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' All part of the hydrologic cycle' - jamese


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

GEOGRAPHY 12:RIVER FORMATIONShttp://webs.cmich.edu/resgi/links.asp?mc=Other%20Resource%20Links&cad=Earth%20Science%20Animations&to=257&tod=River%20Animations


All part of the hydrologic cycle
All part of the hydrologic cycle

http://polaris.umuc.edu/cvu/envm/hydro/hydro.html

`


DRAINAGE BASIN: an area of land from which a stream gets its water supply. It is a region that is grained by a single riverWhat type is seen below?


River confluence joining of 2 rivers
RIVER CONFLUENCE: joining of 2 rivers water supply. It is a region that is grained by a single river


Dendritic water supply. It is a region that is grained by a single riverA branching treelike drainage pattern. In areas of uniform rock, with little distortion by folding or faulting, the rivers develop a random branching network similar to a tree


Dendritic
Dendritic water supply. It is a region that is grained by a single river


Trellis water supply. It is a region that is grained by a single riverA rectangular drainage pattern. It occurs when the rock structure steers streams into a parallel course, with tributaries joining at almost right angles..


Trellis drainage pattern
Trellis drainage pattern water supply. It is a region that is grained by a single river


Radial water supply. It is a region that is grained by a single riverA spokelike pattern of rivers. These tend to flow away from the summit of a dome or volcano in all directions.


Radial pattern
Radial pattern water supply. It is a region that is grained by a single river


Oahu hawaii
Oahu, Hawaii water supply. It is a region that is grained by a single river


Mt st helens and what is left of radial drainage
Mt. St. Helens, and what is left of radial drainage water supply. It is a region that is grained by a single river


River stages
River Stages water supply. It is a region that is grained by a single river


Following a river
Following a river water supply. It is a region that is grained by a single river

The Rhine River


Youthful river
Youthful River water supply. It is a region that is grained by a single river

  • Youth stage-cuts a deep V-Shaped valley as the fast moving water transports material downstream. Dominated by erosion and very little depositionfeatures: include rapids, waterfalls, and various sizes of boulders along the river bed.


Mature stage
Mature Stage water supply. It is a region that is grained by a single river

  • Mature Stage: Drainage pattern is evident. Vertical erosion is evident, but downstream lateral erosion of banks is evident as meanders and a flood plain take shape. Velocity slows and deposition is common.

  • Deposition>erosion


Old stage
Old Stage water supply. It is a region that is grained by a single river

  • Old Stage: Extensive floodplain and meandering occur. River cuts across meanders to create oxbox lakes. Flooding of rich alluvium and natural levees are prominent. The river delta is well developed and continues to grow.

  • Flooding deposits rich alluvium (sand, silt, and clay for farming) with natural levees along river banks


Rejuvenated river
Rejuvenated River water supply. It is a region that is grained by a single river

  • Rejuvenated Stage-The land has undergone a slow uplifiting and caused the river to return to a period of vertical erosion as was the case in the youthful stage

  • Deep v-shaped valley prominent

  • River cuts through the floodplain created until its elevation nears sea level


Work of rivers
Work of rivers water supply. It is a region that is grained by a single river

3 functions

  • Erosion

  • Transportation

  • Deposition

    http://www.bbc.co.uk/schools/gcsebitesize/geography/coastal/coastalprocessesrev4.shtml


Transportation
Transportation water supply. It is a region that is grained by a single river

http://library.thinkquest.org/28022/transport/index.html


River meanders
River Meanders: water supply. It is a region that is grained by a single river


River erosion and deposition
RIVER EROSION AND DEPOSITION: water supply. It is a region that is grained by a single river

Cut off slope

aka cutbank

Point bar or

slip off slope


River erosion
River Erosion water supply. It is a region that is grained by a single river


River bank erosion and deposition
River Bank erosion and deposition: water supply. It is a region that is grained by a single river


Point bar
Point bar: water supply. It is a region that is grained by a single river


Lateral erosion
Lateral erosion water supply. It is a region that is grained by a single river


Stream meandering
Stream Meandering water supply. It is a region that is grained by a single river

  • Graded streams may erode horizontally in process called meandering

  • Cutbanks form on outside of meanders (fast), while point bars form on the inside (slow)

Stream Meandering


How oxbow lakes form
How Oxbow Lakes form: water supply. It is a region that is grained by a single river


Formation: water supply. It is a region that is grained by a single riverWhen meander bends become giant loops, there is a thin piece of land left between the beginning and the end of the meander. This is the meander neck.


As the river neck becomes very narrow, water supply. It is a region that is grained by a single riverthe river can break through. For a short time, water flows both round the meander (which is now called a backwater) and across the meander neck.


Eventually the river cuts off the backwater completely and flows across what used to be the meander neck. For a short time, an oxbow lake is left behind.


The oxbow lake lasts until it becomes overgrown with weeds and filled in with soil. This happens quite quickly as it is cut off from the main river and therefore doesn't get any water. This is called a MEANDER SCAR


Oxbow lake formation
Oxbow Lake formation: and filled in with soil.


Oxbow lakes on a topographic map http www sln org uk geography oxbow
Oxbow lakes on a topographic map: and filled in with soil. http://www.sln.org.uk/geography/oxbow/


Open meander erode on outside deposit on inside
OPEN MEANDER: and filled in with soil. erode on outside, deposit on inside



Oxbow lake standing water once river cuts off meander
OXBOW LAKE: and filled in with soil. standing water once river cuts off meander


Meander scar dried up oxbow lake
MEANDER SCAR: and filled in with soil. dried up oxbow lake.


Levees formations common to old age rivers
Levees: and filled in with soil. formations common to old age rivers


Levees form by the spill-over of sediment during and filled in with soil. floods. Next to the channel most of the coarse sediment is deposited and finer muds and clays are deposited farther away. Thus, over time these near-channel sand deposits will rise above the floodplain and form natural levees. Extends into a terrace over time-Let’s watch an animation!


Levee
levee and filled in with soil.


Levee1
levee and filled in with soil.


Levee2
levee and filled in with soil.


Braided stream
Braided stream: and filled in with soil.


Features of a typical floodplain
Features of a typical floodplain and filled in with soil.


River deltas
River Deltas and filled in with soil.

  • A river carries sediment from its drainage basin toward the seaends up being deposited on the floodplain when the stream flow slows down.

  • Some deposits are light enough to be deposited in the sea.

  • They form river deltassand is deposited closest to shore (heaviest), followed by silt and clay (lighter)

  • Below is an image of the Fraser River Deltaestuarine river delta


ARCUATE DELTA: Has many distributaries that carry water and sediment across a very symmetrical delta that has the shape of an inverted cove ex.NILE RIVER DELTAnumber of distributaries flowing across the delta (eg the Nile delta). An arcuate delta forms when a river meets the sea in a place where the waves, currents, and tides are strong


Nile river delta
Nile River Delta sediment across a very symmetrical delta that has the shape of an


BIRD’S FOOT DELTA sediment across a very symmetrical delta that has the shape of an : From the picture, it is quite evident that it does not look like a bird's foot (C) delta as shown below. A bird's foot delta forms where sediment is deposited in relatively calm offshore waters. An example of a bird's foot delta is the Mississippi river delta.


ESTUARINE DELTA: sediment across a very symmetrical delta that has the shape of an e.g., Seine River of France.  This type of delta has a river that empties into a long, narrow estuary that eventually becomes filled with sediment (inside the coastline).When the mouth of a river enters the sea and is inundated (overtaken) by the sea in a mix with freshwater and very little delta, it is called an estuary.Another example would be Delta, British Columbiahttp://www.semi.sd36.bc.ca/mleziva/unit6/U06L02.htm


A cuspate delta is formed when a river drops sediment onto a straight shoreline with strong waves. Waves force the sediment to spread outwards in both directions from the river's mouth making a pointed tooth shape with curved sides. An example is the Tiber delta in Italy.


Alluvial fans: straight shoreline with strong waves. Waves force the sediment to spread outwards in both directions from the river's mouth making a pointed tooth shape with curved sides. An example is the Tiber delta in Italy. Created by alluvial aggradation (ACCUMULATION) in areas of high relief where bedload-dominated streams flow out of mts onto plain – stream sweeps side to side over time, making fan shape – most common in desert climates


Dams and reservoirs
Dams and Reservoirs straight shoreline with strong waves. Waves force the sediment to spread outwards in both directions from the river's mouth making a pointed tooth shape with curved sides. An example is the Tiber delta in Italy.

  • Dam – engineered obstruction across a river to control its flow – usu. holds back lake or reservoir

  • Why dams?

    • 1. Hydroelectric energy

    • 2. Flood control

    • 3. Enhance river navigation

    • 4. Surface water supply

Hoover Dam


Negatives of dams
Negatives of Dams straight shoreline with strong waves. Waves force the sediment to spread outwards in both directions from the river's mouth making a pointed tooth shape with curved sides. An example is the Tiber delta in Italy.

  • Expense

  • Refugees from areas flooded by dam

  • Loss of ecosystems & scenery

  • No floods/No soil replenishment in floodplain (downstream)

  • Stop spawning fish from going upstream

  • Increase in GHG’s because of lake where flora decomposes

  • Disease: organisms that thrive in warm water eg. Schistosomiasis aka Bilharzia-quite evident in Egypt’s Aswan Dam

    http://en.wikipedia.org/wiki/Schistosomiasis

  • Watch Animation

  • http://www.brainpop.com/search/search.weml


ad