Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

28
Chapter 9 Chapter 9 Water Erosion and Water Erosion and Deposition Deposition 9.1 Water Erosion and 9.1 Water Erosion and Deposition Deposition Notes Sheet Notes Sheet

Transcript of Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Page 1: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Chapter 9 Chapter 9 Water Erosion and Water Erosion and

DepositionDeposition

9.1 Water Erosion and 9.1 Water Erosion and DepositionDeposition

Notes SheetNotes Sheet

Page 2: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

RunoffRunoff

Water that flows Water that flows across the Earth’s across the Earth’s surface is called surface is called runoffrunoff. The water . The water does not soak into does not soak into the the groundground or or evaporateevaporate..

Page 3: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

RunoffRunoff

The amount of The amount of rainrain and length of and length of timetime it falls it falls are two factors that determine whether water are two factors that determine whether water will soak into the ground or will soak into the ground or run offrun off..

Light rainLight rain falling over several hours will have falling over several hours will have time to time to soaksoak into the ground. into the ground.

Heavy rainHeavy rain falling in less than an hour will falling in less than an hour will run offrun off because it can’t soak into the ground fast because it can’t soak into the ground fast enough.enough.

Page 4: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

RunoffRunoff

The steepness, or The steepness, or slopeslope, of the land , of the land also determines runoff.also determines runoff.

Water moves Water moves quicklyquickly down steep slopes down steep slopes so it has little time to soak into the ground.so it has little time to soak into the ground.

Water moves more Water moves more slowlyslowly down gentle down gentle slopes and across slopes and across flatflat area, allowing time area, allowing time to soak into the ground.to soak into the ground.

Page 5: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

RunoffRunoff

VegetationVegetation, such as grass and trees, , such as grass and trees, also effects the amount of runoff.also effects the amount of runoff.

Runoff Runoff slows downslows down when it flows around when it flows around plants.plants.

By slowing down By slowing down runoffrunoff, plants and their , plants and their rootsroots prevent soil from being prevent soil from being carried awaycarried away..

Page 6: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

RunoffRunoff

GravityGravity is the attracting force that all objects is the attracting force that all objects have for one another. The greater the have for one another. The greater the massmass of an object the greater the forces of gravity.of an object the greater the forces of gravity.

Water runs Water runs downhilldownhill because of gravity. because of gravity.

When water runs down a slope it picks up When water runs down a slope it picks up speedspeed. As speed increases so does it . As speed increases so does it energyenergy..

Fast moving water carries more Fast moving water carries more soil soil than slow than slow moving water does.moving water does.

Page 7: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Water ErosionWater Erosion

The movement of soil and rock from The movement of soil and rock from one place to another is called one place to another is called erosionerosion. . Water is an agent of erosion.Water is an agent of erosion.

Page 8: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Water ErosionWater Erosion

Running water can leave a groove or small Running water can leave a groove or small ditchditch on on the side of the slope. This is evidence of the side of the slope. This is evidence of rill rill erosion.erosion.

Rill erosion begins when a small stream forms during a heavy rain.Rill erosion begins when a small stream forms during a heavy rain.As the stream flows along it has enough energy to As the stream flows along it has enough energy to erodeerode and carry and carry away away soilsoil..Water moving along the same path creates a groove called a Water moving along the same path creates a groove called a channelchannel on the slope where the water eroded the soil. on the slope where the water eroded the soil.If the water flows in the same channel, the channel becomes If the water flows in the same channel, the channel becomes broaderbroader and deeper and turns into and deeper and turns into gullygully erosion. erosion.

Page 9: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Water ErosionWater Erosion

Water often Water often erodeserodes without being in a without being in a channelchannel..

Rainwater can flow off surfaces in thin, broad Rainwater can flow off surfaces in thin, broad sheets, like off the hood of a car.sheets, like off the hood of a car.

Sheet erosion occurs when water that is flowing Sheet erosion occurs when water that is flowing as sheets picks up and carries away sediments.as sheets picks up and carries away sediments.

Page 10: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Water ErosionWater ErosionSometimes water continues to Sometimes water continues to flow along the flow along the low placelow place, or , or channel, it has formed.channel, it has formed.A stream channel becomes A stream channel becomes deeperdeeper and and widerwider as water picks as water picks up sediments from the bottom and up sediments from the bottom and side of the channel.side of the channel.The sediment it carries is called The sediment it carries is called it’s it’s loadload..

Water picks up and Water picks up and carriescarries lightweight lightweight sediments sediments called called the the suspendedsuspended load. load.

Larger Larger heavyheavy particles called particles called the the bed bed load just roll along the load just roll along the bottom of the stream bottom of the stream channelchannel..

Page 11: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Water ErosionWater Erosion

Water can even dissolve some rocks and Water can even dissolve some rocks and carry them away in solution.carry them away in solution.

The different sized sediments scrape The different sized sediments scrape against the bottom and the sides of against the bottom and the sides of channels and wear away the rock by the channels and wear away the rock by the process of process of abrasionabrasion..

Page 12: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

River System DevelopmentRiver System Development

Streams are part of Streams are part of riverriver systems. systems.

The water comes from The water comes from rills, gulliesrills, gullies, and , and smaller streams located upstream.smaller streams located upstream.

Runoff enters Runoff enters smallsmall streams, which join streams, which join together to form together to form largerlarger streams. Larger streams. Larger streams come together to form streams come together to form riversrivers, , which grow as more streams join.which grow as more streams join.

Page 13: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

River System DevelopmentRiver System Development

A drainage basin is the area of land A drainage basin is the area of land from which a stream or river collects from which a stream or river collects runoffrunoff..A A drainage basindrainage basin is like a is like a bathtubbathtub-all water -all water that collects in it flows toward one location that collects in it flows toward one location the the draindrain. All the water in a river system . All the water in a river system flows to the main river. flows to the main river. The The Mississippi RiverMississippi River drainage basin is the drainage basin is the largest in the U.S.largest in the U.S.

Page 14: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

The mighty MississippiThe mighty Mississippi

Page 15: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Stages of Stream DevelopmentStages of Stream Development

Streams come in a variety of forms-some are Streams come in a variety of forms-some are narrow and narrow and fastfast moving, others are wide and moving, others are wide and slowslow moving. moving.

Streams differ because they have different Streams differ because they have different stages of stages of developmentdevelopment..

These stages depend on the These stages depend on the slopeslope of the ground of the ground over which the stream flows.over which the stream flows.

The names of the stages of development are not The names of the stages of development are not always related to the actual always related to the actual ageage of the river. of the river.

Page 16: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Stages of Steam DevelopmentStages of Steam Development

A stream that flows swiftly through a A stream that flows swiftly through a steep valley is a steep valley is a young streamyoung stream..

A young stream may have whitewater A young stream may have whitewater rapidsrapids and and waterfallswaterfalls..

Has a Has a highhigh level of energy and level of energy and erodeserodes the the stream bottom faster than the stream bottom faster than the sidessides..

Page 17: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Young StreamYoung Stream

Page 18: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Stages of Stream DevelopmentStages of Stream Development

A A maturemature stream flows more smoothly stream flows more smoothly through it’s valley. Most of the rocks in through it’s valley. Most of the rocks in the streambed that cause waterfalls the streambed that cause waterfalls and and rapidsrapids are are erodederoded by running water by running water and the and the sedimentssediments it carries it carries..

Erosion is no longer concentrated on the Erosion is no longer concentrated on the bottombottom of the stream channel. of the stream channel.

Page 19: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Mature StreamMature Stream

Page 20: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Stages of Stream DevelopmentStages of Stream Development

A mature stream erodes A mature stream erodes more along the more along the sidessides and and curvescurves develop. These develop. These forms form because the forms form because the speedspeed of water changes of water changes throughout the throughout the widthwidth of of the channel.the channel.

Water in shallow area of a Water in shallow area of a stream moves stream moves slowerslower because it drags along because it drags along the bottomthe bottom

In the deeper part of the In the deeper part of the river, the water moves river, the water moves fasterfaster..

Page 21: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Stages of Stream DevelopmentStages of Stream Development

If the deep part of the channel is next to If the deep part of the channel is next to one side of the one side of the riverriver, water will erode that , water will erode that side and form a slight curve.side and form a slight curve.

Over time the curve grows into a meander.Over time the curve grows into a meander.

The broad The broad flat flat valley floor formed by a valley floor formed by a meandering stream is called a meandering stream is called a flood plainflood plain..

Page 22: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Stages of River DevelopmentStages of River Development

The last stage of river development is the The last stage of river development is the oldold stage. stage.

An old stream flows smoothly through a An old stream flows smoothly through a broad broad floodplainfloodplain..

Major river systems contain streams in all Major river systems contain streams in all stages of stages of developmentdevelopment..

When a river system has too much water in When a river system has too much water in it, it, floodsfloods can occur. These can be can occur. These can be catastrophic and cause major damage.catastrophic and cause major damage.

Page 23: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Old StreamOld Stream

Page 24: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

River System PictureRiver System Picture

Page 25: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Deposition by Surface WaterDeposition by Surface Water

As water moves through a river system it loses some of As water moves through a river system it loses some of its energy of its energy of motionmotion. The water can no longer carry . The water can no longer carry some of its some of its sedimentsediment. As a result, sediment is . As a result, sediment is depositeddeposited to the bottom of the stream.to the bottom of the stream.Sediment can be carried for long or short Sediment can be carried for long or short distancesdistances..Sediment that is deposited as water empties into an Sediment that is deposited as water empties into an ocean or ocean or lakelake form a triangular or fan-shaped deposit form a triangular or fan-shaped deposit called a called a deltadelta..When river water empties from a mountain valley onto When river water empties from a mountain valley onto an open an open plainplain, the deposit is called an , the deposit is called an alluvialalluvial fan. fan.

Page 26: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Flood PlainFlood Plain

Is the flat area on Is the flat area on each side of a river each side of a river that is submerged that is submerged during a flood.during a flood.

Page 27: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

DeltaDelta

Deposition of sediments when a river empties Deposition of sediments when a river empties into a body of waterinto a body of water

Page 28: Chapter 9 Water Erosion and Deposition 9.1 Water Erosion and Deposition Notes Sheet.

Alluvial FanAlluvial Fan

A cone shaped deposition of sediment where A cone shaped deposition of sediment where moving water empties onto dry land (arid moving water empties onto dry land (arid regions)regions)