Running WaterRunning Water

Running waterRunning water

Water as an agent of Water as an agent of erosion; water in erosion; water in streams, tributaries streams, tributaries (larger streams) (larger streams) and rivers that flow and rivers that flow down hill therefore down hill therefore changing the changing the landscape (erosion)landscape (erosion)

Running waterRunning water

• AbrasionAbrasion – – wearing wearing away of away of rock by rock by grinding grinding actionaction

3 ways rock is carried by 3 ways rock is carried by waterwater• SolutionSolution – mineral matter dissolved from – mineral matter dissolved from

bedrock is carried in a river (25%)bedrock is carried in a river (25%)

3 ways rock is carried by 3 ways rock is carried by waterwater• SuspensionSuspension – small rock materials, silt and – small rock materials, silt and

clay, carried by a river are stirred up & kept clay, carried by a river are stirred up & kept from sinking by the turbulence of stream from sinking by the turbulence of stream flow (50%)flow (50%)

3 ways rock is carried by 3 ways rock is carried by waterwater

• Bed LoadBed Load – sand, – sand, gravel, pebbles, gravel, pebbles, and boulders that and boulders that are moved along are moved along the bed of a the bed of a stream & that are stream & that are too heavy to be too heavy to be carried in carried in suspension (25%)suspension (25%)

• Carrying Power Carrying Power – how much total – how much total sediments a stream can carry and sediments a stream can carry and the size of the particles being carried the size of the particles being carried by the stream at given time and by the stream at given time and stream velocitystream velocity

• DischargeDischarge – volume of water flowing – volume of water flowing past a given point in a stream at a past a given point in a stream at a given timegiven time

• Stream VelocityStream Velocity – the speed of water – the speed of water at a given point at a given time at a given point at a given time

• Drainage systemDrainage system - Streams flow into - Streams flow into larger streams (tributaries), which flow larger streams (tributaries), which flow into rivers, which flow into oceans … into rivers, which flow into oceans … cumulative denotes a “drainage cumulative denotes a “drainage system”system”

Lengthening of a valley…Lengthening of a valley…

• GullyGully – a miniature – a miniature valley formed by valley formed by erosion from heavy erosion from heavy rainsrains

• Headward ErosionHeadward Erosion – wearing away – wearing away of land at the head of a gully or a of land at the head of a gully or a stream valleystream valley

More Headward More Headward ErosionErosion

More More Headward Headward ErosionErosion

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• Drainage Basin (watershed)Drainage Basin (watershed) – an – an area of land who’s runoff supplies water area of land who’s runoff supplies water to the stream of a drainage system - to the stream of a drainage system - area drained by a river systemarea drained by a river system

• Base Level Base Level – the level of the body – the level of the body of water into which a stream flowsof water into which a stream flows

DivideDivide – the higher land separating – the higher land separating two adjacent drainage basinstwo adjacent drainage basins

•

Continental DivideContinental Divide

made of Rocky Mountains and Sierra made of Rocky Mountains and Sierra Madre Occidental Mountains Madre Occidental Mountains – Streams on the East drain into the Streams on the East drain into the

Atlantic Ocean or Gulf of MexicoAtlantic Ocean or Gulf of Mexico– Streams to the West drain into the Streams to the West drain into the

PacificPacific

• Stream PiracyStream Piracy – the diversion – the diversion of the upper of the upper part of one part of one stream by the stream by the headward headward growth of growth of another streamanother stream

• Water GapWater Gap – a pass – a pass

in a mountain in a mountain

ridge through ridge through

which a which a

stream flows, stream flows,

created by created by

resistant rock resistant rock

layerslayers

Life of a RiverLife of a River

A Youthful Stream A Youthful Stream

• Narrow V-shaped Narrow V-shaped valleyvalley

• Down cutting Down cutting

• Swift water Swift water

• Steep gradient Steep gradient

• Erosion is Erosion is dominant dominant

Mature StreamMature Stream

• Lateral Erosion Lateral Erosion begins begins

• Meanders Meanders develop develop

• Floodplains Floodplains develop develop

• Gradient lowers Gradient lowers

Old AgeOld Age• Wide meanders and Wide meanders and

oxbow lakes oxbow lakes • Wide floodplain Wide floodplain • Low velocity Low velocity • Low gradient Low gradient • Dynamic Dynamic

equilibrium equilibrium between erosion between erosion and deposition and deposition

Flow speedFlow speed

High velocity High velocity (erosion):(erosion):• Outside of curveOutside of curve• Middle of surfaceMiddle of surface• Well below the surfaceWell below the surface• Increase in dischargeIncrease in discharge• Increases with Increases with increase increase in gradientin gradient

Flow speedFlow speed

Low velocity Low velocity (deposition):(deposition):

• Inside of curveInside of curve

• Edges of river Edges of river surfacesurface

• Decrease in Decrease in dischargedischarge

• Decreases with Decreases with decrease in decrease in gradientgradient

Stream features depend on 3 major Stream features depend on 3 major thingsthings

1. The type of rock being eroded.1. The type of rock being eroded.

2. The amount of water & sediment2. The amount of water & sediment

3. The climate of the area3. The climate of the area

Features…Features…

MeanderMeander – a curve in a mature or old – a curve in a mature or old streamstream

Mississippi RiverMississippi River

Features…Features…

• Oxbow Lake – Oxbow Lake – crescent- shaped crescent- shaped lake formed when a river meander lake formed when a river meander gets cut off from the river and the gets cut off from the river and the ends of the original bend have ‘silted ends of the original bend have ‘silted up’up’– Erosion on the outside bend of a riverErosion on the outside bend of a river– Deposition of the inside bend of a riverDeposition of the inside bend of a river

Features…Features…

• FloodplainFloodplain – the broad flat valley – the broad flat valley floor carved by a meandering stream floor carved by a meandering stream and often covered with water when a and often covered with water when a stream floodsstream floods

• LeveeLevee – a natural or artificial bank – a natural or artificial bank confining a stream or river channelconfining a stream or river channel

Flash FloodFlash Flood – a – a sudden rush of sudden rush of water, usually water, usually caused by a single caused by a single cloudburst over the cloudburst over the narrow valley of a narrow valley of a young mountain young mountain streamstream

3 Common types of natural dams3 Common types of natural dams

A. landslidesA. landslides

B. ice jams B. ice jams

C. volcanoesC. volcanoes

3 Common types of artificial flood 3 Common types of artificial flood controlcontrol

A. build up leveesA. build up levees

B. pump rising water into back B. pump rising water into back swamp swamp reservoirsreservoirs

C. build a series of dams and C. build a series of dams and control the control the overall flow of the overall flow of the riverriver

• PotholePothole – deep – deep oval or circular oval or circular holes cut into a holes cut into a stream bed by stream bed by abrasion from abrasion from swirling sand & swirling sand & pebbles. Very pebbles. Very large ones are large ones are called called plunge plunge poolspools

• DeltaDelta – a fan-shaped deposit of sediment – a fan-shaped deposit of sediment formed at the mouth of a stream or river formed at the mouth of a stream or river when it flows into a quiet body of water, when it flows into a quiet body of water, such as a lake, gulf, or inland sea (ex. such as a lake, gulf, or inland sea (ex. Mississippi & Nile river deltas)Mississippi & Nile river deltas)

Laizhou BayLaizhou Bay ( (Laizhou WanLaizhou Wan) is the southern arm of ) is the southern arm of the Bohai Sea (also Known as the the Bohai Sea (also Known as the Bohai BayBohai Bay, or just , or just Bo HaiBo Hai), which is a large relatively shallow extension ), which is a large relatively shallow extension of the Korea Bay of the Korea Bay

Nile River DeltaNile River Delta

Alluvial FanAlluvial Fan – – sloping sloping triangular triangular deposits of deposits of sediment sediment located where a located where a mountain mountain stream reaches stream reaches level land (ex. At level land (ex. At the foot of the the foot of the Rocky Mountains Rocky Mountains and the Sierra and the Sierra Nevada’s)Nevada’s)

Angel Falls, Venezuela Angel Falls, Venezuela

Victoria Falls, ZimbabweVictoria Falls, Zimbabwe

Niagara FallsNiagara Falls

Online practice quiz…Online practice quiz…

•http://www.uh.edu/~jbutler/physical/chap13mult.html

•Problem: What factors cause the greatest stream erosion?

•Compare: straight, curvy, very curvy and various heights (1, 2, 3 books)

•Problem: What factors cause the greatest stream erosion?

•Compare: straight, curvy, very curvy and various heights (1, 2, 3 books)

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ProblemProblem

(research)(research)

HypothesisHypothesis

Design and perform experiment (procedure)Design and perform experiment (procedure)

Collect DataCollect Data

Analyze DataAnalyze Data

ConclusionConclusion