Tees River Processes and Land Forms 3436

8/3/2019 Tees River Processes and Land Forms 3436

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River Tees

from source to mouth (137km; 85mi)


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River Tees source


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Upper valley characteristics


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Vshapevalley, verticalerosion

dominant


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dominantInterlockingspurs


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Slumpingandlandslides -very activehillslopes


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Terracettesformed by soil

creep


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Terracettesformed by soil

creepNarrow,shallowchannel, lowvelocity and

discharge


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Terracettesformed by soilcreep

Narrow,shallowchannel, lowvelocity anddischarge

Large bedloadderived fromupstream andfrom valleysides


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Interlocking spurs,

Lake District

A typical uppercourse valleywithinterlockingspurs, steepvalley sides andactive slopeprocesses


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Choked runnel, Dark Peak

Ephemeral stream

or runnel - waterpresent only duringhigh rainfall events


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Debris brought

downslopetowards channel -dropped whenwater disappearsafter storm

Ephemeral stream

or runnel - waterpresent only duringhigh rainfall events


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Debris brought

downslopetowards channel -dropped whenwater disappearsafter storm

Ephemeral stream

or runnel- waterpresent only duringhigh rainfall events

Verticalerosion

creatingsteep, bareslopesvulnerable tofurther

erosion - anexample ofpositivefeedback in aslope system


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River load in upper course

Load is dumped in summer due tothe low discharge unable to carry

the c________and c__________of load at higher flow levels


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the capacity and competence ofload at higher flow levels


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Boulders are large and semi-rounded,due to attrition within the loadandabrasion with the stream bed andbanks




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Rapids in the Upper Tees Valley


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Rapids aremini-waterfalls

Protruding bandsof more resistant

strata createsteps over whichrapids fall - theriver bed isungraded


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Shallow, slowflowing river due tolarge amount offriction.


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Wetted perimeter

is large comparedto cross sectionalarea of water -resulting in a low????????????


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Wetted perimeter

is large comparedto cross sectionalarea of water -resulting in a lowhydraulic radius

(low efficiency)


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Tees above High Force


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Tees: Cauldron Snout


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High Force


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High Force waterfall, R. Tees

Huge step in riverbed due to igneousintrusion of doleriteinto the limestone.


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Plunge poolwhere thedolerite wall isundercut,causing rockfalls

and recession ofthe waterfall


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Waterfallcreates gorgeas it recedes

upstream byeroding thebase and neck




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High Force


The longprofile will begraded overtime

Waterfallcreates gorgeas it recedes

upstream byeroding thebase and neck




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Headward erosion,

R. Colorado


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Headward erosion, R. Colorado

River seeps out

from spring atbase andunderminessteep cliff,causing

rockfalls andheadwall


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Headward erosion, R. Colorado

Rivers erode in

a headwarddirection,eating backinto plateau

River seeps out

from spring atbase andunderminessteep cliff,causing

rockfalls andheadwall


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Potholes in R. Wharfe

Smooth sculpturingof rock byabrasion, showing

evidence of waterlevels during highdischarge events

Vertical erosion

is dominant


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Close-up of potholes


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Close-up of potholes


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Close-up of potholesCircular potholesdue to eddyingmotion whenriver energy ishigh


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Potholes will jointogether byabrasion, anddeepen byverticalerosion


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Load is picked upand used to scouror abrade pothole.Load itselfbecomes roundedby attrition

Potholes will jointogether byabrasion, anddeepen byverticalerosion


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Potholes, human scale!!


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Middle course, R. Tees


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Valley opensout, more gentleslopes, widervalley bottom


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First signs ofmeanders


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Floodplain


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Floodplain

River channelwider, deeper,greater

velocity anddischarge


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Tees middle course


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Meander


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Helical flow in a meander


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Thalweg, riffles, pools


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Meander

FloodplainPoint bardepositson the

innermeanderbendwherethere islowenergy


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Meander

Floodplain

Steep bankknown as theriver bluff orcliff, caused byconcentratederosion due tothe

Point bardepositson the



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Meander

Floodplain

Steep bankknown as theriver bluff orcliff, caused byconcentratederosion due tothe thalweg and

helicoidal flow




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Meander

Floodplain

Steep bank

known as theriver bluff orcliff, caused byconcentratederosion due tothe thalweg andhelicoidal flow.




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Meander

FloodplainSteep bankknown as theriver bluff orcliff, caused by

concentratederosion due tothe thalweg and



helicoidalflow

poolriffle

pool

Pools develop atmeander bends andriffles in thestretches betweenbends


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Meander on the R. Colorado


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Meander on the R. ColoradoMeander incised intoplateau due torejuvenation


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Different stratashow evidence ofpast climates orhydrologicalevents


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Different stratashow evidence ofpast climates orhydrologicalevents.

Stratum withlarge bouldersmust have formedin wetterconditions whenhigher riverdischarge carried


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Migrating meanders, R.

Gongola, Nigeria


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Migrating meanders, R.

Gongola, Nigeria

Former course

marked by whitesediments

Current

channel isbraided


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River terraces, R. Agri, S.

Italy


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Italy

River has beenrejuvenated

causing renewedvertical erosion -base level hasdropped eitherdue to rising land

or falling sealevel


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Italy Flat terracesrepresent formerfloodplains

River has beenrejuvenated

causing renewedvertical erosion -base level hasdropped eitherdue to rising land

or falling sealevel


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Tees middle course


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Flooding in the Severn Valley


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Floodplain can bemapped into riskzones high to low


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Floods can bebeneficial - theyrenew soil fertility bydepositing sediment on

floodplain


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Floods can bebeneficial - theyrenew soil fertility bydepositing sediment on

floodplainFloods result in largeamounts of sedimenttransported in thechannel


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Tees estuary


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Tees mouth

Summary of channel


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ycharacteristics

(1) Processes

Summary of channel


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ycharacteristics

(1) ProcessesErosion

CorrasionAttritionSolutionHydraulic

action

HeadwardVerticalLateral

Summary of channel


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ycharacteristics



action

Transport

SuspensionSolutionBedload

- traction

- saltation


Summary of channel


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ycharacteristics



action

Transport

SuspensionSolutionBedload

- traction- saltation

Deposition


Summary of channel


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Summary of channelcharacteristics

(2) Landforms

Summary of channel


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(2) Landforms

Rapids

Waterfalls

Potholes

Summary of channel


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(2) LandformsRapids

WaterfallsPotholes

Meander

Bluff/cliffPoint bar

Pool

Riffle

Summary of channel


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(2) LandformsRapids

Waterfall

Pothole

Meander

Bluff/cliffPoint bar

Pool

Riffle

Knick point

BraidsDelta

Summary of channel


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(3) Concepts and technical terms

Summary of channel


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(3) Concepts and technical termsDischarge

Regime

- flashy- regular

Capacity

Competence

Summary of channel


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Regime

- flashy- regular

Capacity

Competence

Hydraulicradius

- crosssectionalarea

- wettedperimeter

Summary of channel


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Regime

- flashy- regular

Capacity

Competence

Hydraulicradius

- crosssectionalarea

- wettedperimeter

Long profile

Graded

profile

Rejuvenation

Base level

Summary of channel


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(3) Concepts and technical terms

Discharge

Regime- flashy- regular

Capacity

Competence

Hydraulic radius

- crosssectional

area

- wettedperimeter

Long profile

Gradedprofile

Rejuvenation

Base level

Thalweg

Helicoidalflow

Meandermigration

Summary of valley


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y f ycharacteristics

Summary of valley


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y ycharacteristics

Upper SlumpsLandslidesTerracettes (soil

creep)

Interlocking spursV shaped valley

Summary of valley


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y ycharacteristics

Upper SlumpsLandslidesTerracettes (soil creep)Interlocking spursV shaped valley

Middle Wider valleyGentler valley sides

FloodplainMeanders

Summary of valley characteristics


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Summary of valley characteristicsUpper Slumps

LandslidesTerracettes (soil creep)Interlocking spursV shaped valley

Middle Wider valleyGentler valley sidesFloodplainMeanders

Lower Widest part of valleyTerraces

Documents

Tees River Processes and Land Forms 3436