Transcript Chapters 9 & 10 - Building Directory
Chapters 9 & 10
Water Erosion
Words on Ch 9 Quiz Monday 1/28/08
watershed suspension discharge stream channel delta divide bed load floodplain meander eutrophication
Words on Ch 10 Quiz Tuesday 1/29/08
infiltration zone of saturation permeability karst topography recharge porosity water table aquifer drawdown artesian well
I. Surface Water A. Runoff 1. Water that does not soak into the ground or evaporate 2. Flows across the Earth’s surface 3. Eventually enters streams, lakes, or the ocean
B. Factors Affecting Runoff 1. Rate of Rainfall a) light rain that falls over several hours will soak in more than it runs off.
b) heavy rain that falls quickly will runoff because it does not have time to soak in.
2. Slope of the Land a) Gentle Slope (flat areas): water has time to sink in or evaporate, this causes less runoff b) Steep Slope (hilly areas): gravity causes water to runoff before it sinks in or evaporates.
3. Amount of Vegetation a) plants and their roots soak up water, slows down runoff 4. Soil Permeability a) The more permeable the soil the more water sinks in and the less runoff.
b) Ex. Concrete: impermeable, high amount of runoff
C. Effect of Gravity 1. Earth’s Gravity pulls all objects toward its center 2. Water falls down slope due to the force of gravity 3. Water accelerates down slope at 9.8 m/s
Answer the following in your notes
1. Where does all runoff eventually end?
2. Name four factors that affect runoff.
3. Does runoff increase or decrease with an increase in slope?
4. What causes water to flow downslope?
D. Water Erosion 1. Rill Erosion a) a small temporary stream will form during heavy rains b) the stream has enough energy to carry away plants and soil c) when the stream dries up there is a scar on the side of the slope where the soil has been removed.
2. Gully Erosion a) a broader version of a rill channel b) the channel becomes wider and deeper c) large amounts of soil are removed
3. Sheet Erosion a) water will pile up until it begins moving down a gentle slope b) as it moves it carries sediment with it until it slows down or evaporates.
c) most of the sediments are left behind
4. Stream Erosion a) water becomes a stream when it continues to flow down a depression it has formed.
b) the moving water picks up and knocks off sediment c) Small particles float along as suspended sediments d) large particles roll along the bottom e) some sediment are carried in solution (dissolved) f) As the stream erodes it carries more sediment causing its channel to become wider and deeper.
E. River System Development 1. Order of Development a) Runoff b) Rills, Gullies, Small Streams c) Larger Streams d) River e) A-D run into each other and finally come together to form a river.
2. Drainage Patterns a) Rectangular (Dia.) -flows in the trends of joints in igneous rock -joints: cracks or fractures in rocks
b) Dendritic (Dia.) -Common in areas of Easily Eroded Sedimentary rock -Ex. Mississippi River c) Radial (Dia.) -form in areas of mountains or volcanoes
Answer the following questions in your notes
1. Compare and contrast rill erosion and gully erosion.
2. How does flowing water eventually become a stream?
3. List in order the stages of river system development.
4. Draw three examples of drainage patterns.
F. Stages of Stream Development 1. Stages are described as young, mature, & old 2. These stages are not named for the age of the streams, but for how the stream acts and its characteristics.
3. Young Stream a) move swiftly through a stream valley b) has steep sides in the valley c) may have rapids and waterfalls d) high amount of energy that erodes the bottom of a channel more than the sides.
4. Mature Stream a) move more slowly than a young stream b) erosion is happening more at the sides of the valley than at the stream bottom c) the stream moves faster in some parts than others d) this difference in speed allows curves (meanders) to form e) the broad flat valley floor is the streams floodplain
5. Old Streams a) the last stage in stream development b) flows slowly through a broad flat floodplain c) Is very winding (meandering stream) d) Most major river systems contain streams in all 3 stages of development
6. Diagram of a meandering stream a) floodplain: broad flat areas carved by a meandering stream b) divide: areas of raised elevation that surrounds the sides of a river system c) levee: mounds of small sediment that help contain the river d) cutbank: point on a bend where the water is deeper and faster causing erosion e) pointbar: point on a bend where sediment is deposited
Answer the following
1. What happens to the amount of water in a stream as it becomes an old stream?
2. What happens to the velocity of a stream as it becomes an old?
3. What happens to the width of a stream as it becomes an old stream?
4. What happens to the depth of a stream as it becomes an old stream?
5. What stream drainage pattern is often associated with igneous rock 6. What stream drainage pattern is often found in areas such as mountains or volcanoes?
7. What stream drainage pattern is found in easily eroded sedimentary rock?
G. Deposition by Surface Water 1. Alluvial Fan a) occurs when a stream slows down and drops its sediments b) Is a triangle shaped feature seen at the bottom of a steep slope
2. Delta a) a stream carries sediments until it reaches a lake, gulf, or ocean b) the sediments are then dropped off into the body of water c) Ex. Mississippi Delta: The river drops its sediments into the Gulf of Mexico adding to the Louisiana shoreline
Answer the following questions in your notebook
1. Compare and contrast young, mature, and old streams. (list any differences and similarities) 2. Explain the difference between a delta and an alluvial fan 3. What stream drainage pattern is often associated with igneous rock 4. What stream drainage pattern is often found in areas such as mountains or volcanoes?
5. What stream drainage pattern is found in easily eroded sedimentary rock?
II. Groundwater Systems A. Groundwater 1. Rock particles in the soil contain open spaces (pore spaces) 2. Water soaks through the soil and fills these spaces 3. This water is called groundwater
B. Permeability 1. Permeable a) water can pass through b) a permeable groundwater system has connecting pores c) soil or rock that has many large connecting pores is highly permeable d) Sandstone
2. Impermeable a) water cannot pass through b) Ex. Clay
C. Groundwater Movement 1. Groundwater moves downward until it reaches an impermeable layer a) when water hits this layer it begins to fill up the permeable rock layer
2. Aquifer a) permeable rock that transmits (moves) water freely 3. Zone of Saturation a) area where all the pores in the aquifer are filled with water b) water table: the upper surface of the zone of saturation 4. Zone of Aeration a) space between the water table and the top of the aquifer Groundwater Diagram
D. Wells, Springs, & Geysers 1. Wells a) must be drilled down to at least the top of the water table b) during a dry season a well may go dry as the water table drops c) too many wells in one place can cause them to go dry
d) Artesian Well: water under pressure rises to the surface --requires a sloping aquifer between two impermeable layers --water in the lower part of the aquifer is under pressure by water in the upper part --if a well is drilled in the lower part of the aquifer the pressure forces the water to the surface
Cone of Depression
2. Springs a) in some places the water table meets the Earth’s surface, this water pours out onto the ground as a spring.
b) hot spring: the groundwater is heated by rocks that come in contact with hot magma.
3. Geysers a) a hot spring that erupts periodically b) water is super-heated underground causing pressure to form c) this pressure pushes part of the water up to the surface d) the remaining water boils quickly and erupts out of the opening e) Ex. Old Faithful, Yellowstone Park
Answer the following questions in your notebook
1. Differentiate between permeable and impermeable.
2. When does groundwater stop moving downward?
3. Draw and label the groundwater diagram.
4. Explain how a spring becomes a hot spring 5. What causes pressure to form in a geyser?
E. Groundwater Erosion & Deposition 1. Cave a) Groundwater containing carbonic acid moves through underground
limestone
b) the limestone dissolves more and more forming a cave
c) stalactite: a calcite deposit formed as water evaporates from the ceiling of a cave d) stalagmites: a calcite deposit formed as water drips from a cave ceiling
2. Sinkholes a) underground rock is dissolved near the surface b) as it dissolves more of the roof collapses and the ground above falls in
Answer the following questions in your notebook
1. What type of rock commonly erodes to form caves?
2. Compare and contrast stalactites and stalagmites.
III. Ocean Shoreline A. Shoreline Forces 1. Waves a) waves move sediment along the beaches b) the waves erode and redeposit sediment
2. Tides a) the rising and falling of the tides moves sediments up and down the shore.
b) rip current (rip tide): a strong current caused by the falling tide, this current causes sediment to be carried out to sea.
3. Longshore Current a) waves hit the shoreline at an angle creating a current b) this current runs parallel to the shore c) these currents are known as rivers of sand, can move several tons of sand a day
B. Rocky Shorelines 1. Rocks and Cliffs are the most common features 2. Waves break rock fragments off the cliffs a) these fragments act like sandpaper eroding softer sediments b) the harder sediments are left behind as rock islands (stacks)
C. Sandy Beaches 1. Beaches a) deposits of sediment that run parallel to the shore b) extend inland as far as the waves and tides are able to deposit them
c) sand is made from where the sediments come from --most sand = quartz --black sand = basalt, ex. Hawaii --green sand = olivine --white sand = coral and shell fragments
D. Sand Erosion & Deposition 1. Erosion a) Longshore current is constantly removing sand from beaches b) storms and wind also remove sand c) erosion causes beaches to be constantly changed
2. Deposition a) sand that is removed by erosion is eventually deposited somewhere else b)
baymouth bar:
a deposit of sand that blocks the opening of a bay c)
spit:
a hook shaped deposit of sand extending out into a bay d)
barrier island:
sand deposits that are parallel to the shore but are completely separated and exposed
Answer the following questions in your notebook
1. What is a rip tide?
2. What type of ocean current is known as a river of sand?
3. What determines the color of the sand on the world’s beaches?
4. Name and describe three features deposited by a longshore current. (last item in your notes) 5. Write your answers to your test review on a separate sheet of paper.
The three ways in which a stream carries its load are in solution, suspension, and ____.
a. stream velocity c.
bed load b. stream channel d.
channel capacity
Which of the following statements is true about the development of a stream?
a.
A stream’s slope increases as it approaches base level.
b. Water along the sides and bottom of the channel flows more rapidly.
c. Deposition is greater in the outside curve of a meander.
d. The velocity of water is greater along the outside of a meander curve.
A(n) ____ is the triangular or fan-shaped deposit of sediment that forms where a river empties into an ocean or lake.
a. alluvial fan b. delta c.
d.
meander drainage basin
A(n) ____ forms when river waters empty from a mountain valley out onto a flat open plain.
a. alluvial fan b. delta c.
d.
meander drainage basin
When people remove vegetation, they ____ runoff and the erosion process.
a. slow down c.
decrease b. speed up d.
do not affect
____ determines the amount of runoff.
a. The amount of vegetation b. The slope of the land c. The amount of rain d. all of the above
A(n) ____ is a layer of permeable rock that lets water move freely.
a. cave c.
aquifer b. water table d.
spring
In dry seasons, some wells go dry because the ____ drops.
a. drainage basin c.
aquifer b. water table d.
spring
Sand is carried down beaches by ____ to form features such as baymouth bars and spits.
a. storms b. wind c.
d.
longshore currents groundwater
Runoff water ____.
a. supplies water for artesian wells b. eventually enters the ocean c. moves through impermeable rock underground d. supplies water for geysers
Water that doesn't soak into the ground or evaporate, but flows across Earth's surface is called ____.
a. runoff b. groundwater c.
d.
impermeable none of the above
All of the following EXCEPT ____ affect the amount of runoff.
a. length of time rain falls b. amount of rain c. gravity d. altitude
A ____ is the land area from which a stream gets its water.
a. spring c.
drainage basin b. delta d.
floodplain
The ____ River drainage basin is the largest drainage basin in the United States.
a. Missouri c.
Delaware b. Mississippi d.
Ohio
A stream that flows swiftly through a steep valley and has steep sides is a(n) ____ stream.
a. young b. mature c.
d.
old none of the above
A(n) ____ forms when the water table is so close to Earth's surface that water flows out.
a. stalactite c.
aquifer b. artesian well d.
spring
Water that is heated by molten rock will form a(n) ____ if the water table is exposed at Earth's surface.
a. aquifer b. hot spring c.
d.
meander artesian well
Rock that has many large, connected pores is highly ____.
a. permeable c.
eroded b. impermeable d.
none of the above
Sheet erosion occurs when water erodes without being ____.
a. in a river valley b. along a steep hill c. in a channel d. on a broad, flat field
All of the following are characteristics of rocky shorelines EXCEPT ____.
a. sandy beaches c.
small rocks b. cliffs d.
large rocks
Forces that act on shorelines cause them to ____.
a. change constantly b. stay the same c. change now and then d. none of the above
The most common features along rocky shorelines are ____.
a. quiet beaches b. rock and sand deposits c. rocks and cliffs d. all of the above
Sand can form from all of the following EXCEPT ____.
a. coral and shell fragments b. quartz c. basalt d. soil
Hawaii's black sands form from ____.
a. olivine b. basalt c. quartz d. coral and shell fragments
Jamaica's white sands are made of ____.
a. olivine b. basalt c. quartz d. coral and shell fragments
Much of the water that falls on the ground as precipitation ____.
a. enters the ground through the process of infiltration b. evaporates back into the atmosphere c. becomes runoff and finds its way back to the ocean d. forms small pools
What two materials are necessary for the formation of most caves?
a. water and carbon dioxide b. soft water and travertine c. carbonic acid and groundwater d. acidic groundwater and limestone
Which answer below matches the number in the drawing with the correct name of a sedimentary formation?
A. 1-delta, 2-continental rise, 3-flood plain B. 1-alluvial fan, 2-flood plain, 3-delta C. 1-barrier island, 2-continental shelf, 3 alluvial fan D. 1-continental shelf, 2-continental rise, 3-barrier island
Sinkholes associated with natural processes are characteristic of what type of bedrock?
A. Limestone B. Granite C. Basalt D. Gneiss
This picture shows a simple well that was dug down to the groundwater. What probably caused the lower level of groundwater, known as a “cone of depression,” in the vicinity of the well?
A. The weight of the atmosphere presses down on the groundwater in the well.
B. The ground below the well acts as a vacuum sucking out the water.
C. Gravity pulls down the water beneath the well.
D. As water is drawn from the well, it takes time for the groundwater to percolate through the soil and restore the level.
During droughts, lack of rain can lead to wells drying up. This is because the drought has lowered the — A. water table B. water trough C. zone of aeration D. zone of porosity
The picture above shows that one of the main pollution problems associated with sinkholes is that — A. they can destroy roadways B. tractors can fall into them C. homes can be damaged by them D. they can connect directly to the water table
In karst regions, caves are carved by the flow of water through limestone bedrock. How do the stalagmites and stalactites in the caves develop?
A. They are carbonate deposits formed by dripping water in air-filled cavities. B. They are granite intrusions that remain behind after water dissolves the surrounding limestone.
C. They are crystals that grow as water hollows out the cavern.
D. They are carvings made in limestone by the swirling water as it hollows out the cavern.
Caves are found in Virginia’s Valley and Ridge province because the area is underlain by — A. granite B. shale C. gneiss D. limestone
Why does water move more slowly through clay than through humus?
A. Clay has greater permeability.
B. Clay has very small pore spaces. C. Clay prevents capillary attraction of water.
D. Clay reduces evaporation rates.