meandering rivers what is a meander?. formation of meanders
TRANSCRIPT
Meandering RiversMeandering Rivers
WHAT IS A MEANDER?
Formation of MeandersFormation of Meanders
Point bar deposits
Point Bar DepositsPoint Bar Deposits
Point bar deposits grows laterally through time
Meander, R. Lavant, Meander, R. Lavant, ChichesterChichester
Meander, R. Lavant, Meander, R. Lavant, ChichesterChichester
Floodplain
Point bar deposits on the inner meander bend where there is low energy
River Cliff Slip-Off Slope
WHAT DO THE ARROWS POINT TO?WHAT DO THE ARROWS POINT TO?WHICH WAY IS THIS
MEANDER MOVING?WHICH WAY IS THIS MEANDER MOVING?
Cut bank erosion (River Cliff)
Point bar deposits }Meander
loop
WHERE IS EROSION TAKING PLACE?WHERE IS EROSION TAKING PLACE?
WHERE IS DEPOSTION TAKING PLACE?WHERE IS DEPOSTION TAKING PLACE?
A
B
C
D
E
F
Meander on the R. Meander on the R. ColoradoColorado
WHY IS DEPOSITION OCCURING HERE?WHY IS DEPOSITION OCCURING HERE?
How did these
meanders form?
REVISION: What River features do you get here?
Ox Bow Lake FormationOx Bow Lake FormationLOOK AT THE DIAGRAM & EXPLAIN THERE FORMATIONLOOK AT THE DIAGRAM & EXPLAIN THERE FORMATION
Formation of an Oxbow
Ox Bow lake on Ox Bow lake on MississippiMississippi
LevLevee formationee formation
LeveesLeveesWHAT DO YOU THING HUMANS MIGHT HAVE DONE TO THIS LEVEE?WHAT DO YOU THING HUMANS MIGHT HAVE DONE TO THIS LEVEE?
Delta Formation
WHAT IS A DELTA?WHAT IS A DELTA?
DEPOSITON OF MATERIAL BY THE RIVER WHEN IT ENTERS THE SEADEPOSITON OF MATERIAL BY THE RIVER WHEN IT ENTERS THE SEA
WHY DOES IT DROP ITS SEDIMENTWHY DOES IT DROP ITS SEDIMENT
Mississippi Delta from Mississippi Delta from Space Space
MISSISSIPPI
The Nile Delta from spaceThe Nile Delta from space
River NileRiver Nile
Estuary FormationEstuary Formation
The Lower Course of a river valley has been DROWNED by a rise in sea level or a fall in the land level.
HOW DOES THIS DIFFER FROM A DELTA?HOW DOES THIS DIFFER FROM A DELTA?
RAISED VALLEY SIDESRAISED VALLEY SIDES
USING YOUR ATLASFIND AN ESTUARY (LOOK AT THE RIVER THAMES)
USING YOUR ATLASFIND AN ESTUARY (LOOK AT THE RIVER THAMES)
USING YOU ATLASLOCATE THE RHONE DELTA
USING YOU ATLASLOCATE THE RHONE DELTA
The Rhone DeltaThe Rhone Delta
The Rhone Delta S. The Rhone Delta S. FranceFranceLook at p39 and identify the
KEY FEATURES CAN YOU SEE IN THE SATELLITE PHOTO?
Look at p39 and identify the KEY FEATURES CAN YOU SEE IN THE SATELLITE PHOTO?
The Rhone DeltaThe Rhone Delta
WHY HAS A DELTA FORMED HERE? LOOK AT P 39 WHY HAS A DELTA FORMED HERE? LOOK AT P 39
Summary of valley Summary of valley characteristicscharacteristics
Upper Interlocking spurs “V” shaped valley Waterfall Gorge
Middle Wider valley Gentler valley sides
Meanders
Lower Widest part of valley
Floodplain Terraces Ox Bow & Levees Delta, Estuary
The River TeesThe River Tees
TRY AND FIND THE RIVER TEESIN YOUR ATLAS
HINT LOOK AT THE MAP
TRY AND FIND THE RIVER TEESIN YOUR ATLAS
HINT LOOK AT THE MAP
Land Use in Drainage Basin Land Use in Drainage Basin of River Teesof River Tees
WHAT IS THE AREA IN EACH BOX?WHAT IS THE AREA IN EACH BOX?
Upper TeesUpper Tees
WHAT HUMAN INFLUENCES EXIST IN THE MAPS?WHAT HUMAN INFLUENCES EXIST IN THE MAPS?
COW GREEN RESERVOIRCOW GREEN RESERVOIR
The Upper Tees Cronkley The Upper Tees Cronkley ScarScar
WHAT LAND USES CAN YOU SEE IN THE PHOTO?WHAT LAND USES CAN YOU SEE IN THE PHOTO?
WHAT ARE THE KEY GEOGRAPHCIAL FEATURES YOU CAN SEE IN THE PHOTOGRAPHWHAT ARE THE KEY GEOGRAPHCIAL FEATURES YOU CAN SEE IN THE PHOTOGRAPH
MOORLANDMOORLAND
STEEP VALLEY
SLOPE DEBRISSLOPE DEBRIS
TURBULENT RIVER
CHANNEL
TURBULENT RIVER
CHANNEL
Upper TeesUpper Tees
WHAT IS THE NAME OF THE WATERFALL?WHAT IS THE NAME OF THE WATERFALL?
The Lower Course TeesThe Lower Course TeesThe Lower Course TeesThe Lower Course Tees
HOW HAS THE RIVER AND LAND USE CHANGED?HOW HAS THE RIVER AND LAND USE CHANGED?
FLAT VALLEY FLOORFLAT VALLEY FLOOR
WIDE MEANDERSWIDE MEANDERS
URBAN SETTLEMENTURBAN SETTLEMENT
WHAT LAND USE CAN YOU SEE IN THE PHOTOGRAPH?WHAT LAND USE CAN YOU SEE IN THE PHOTOGRAPH?
The Lower TeesThe Lower TeesTEESMOUTH ESTUARYTEESMOUTH ESTUARY
The River meets the SeaThe River meets the Sea
LOOK AT P42WHAT DO YOU THINK THE PHOTOS SHOW?
LOOK AT P42WHAT DO YOU THINK THE PHOTOS SHOW?
WHAT IS THE FUNCTIONOF THE BARRAGE?WHAT IS THE FUNCTIONOF THE BARRAGE?
River ManagementRiver Management
Formation of the Formation of the Mississippi River DeltaMississippi River Delta
Early delta
More recent delta sediments Modern
delta
Causes of FloodsCauses of Floods
A Flood can occur when a river exceeds its bank full stage A Flood can occur when a river exceeds its bank full stage and water will subsequently inundate the adjacent and water will subsequently inundate the adjacent surrounding area.surrounding area.
Heavy rainfallHeavy rainfall - long periods of heavy rainfall will lead to an - long periods of heavy rainfall will lead to an increase in surface runoff and increase in river level.increase in surface runoff and increase in river level.
Snow melt and heavy rainfallSnow melt and heavy rainfall - water in storage may be freed by - water in storage may be freed by Spring melts increasing surface runoff. Spring melts increasing surface runoff.
DeforestationDeforestation - cutting down of trees leads to a reduction in - cutting down of trees leads to a reduction in interception rates and an increase in surface runoff. This may interception rates and an increase in surface runoff. This may also lead to rapid erosion rates due to a lack of stability in the soil also lead to rapid erosion rates due to a lack of stability in the soil subsurface.subsurface.
UrbanisationUrbanisation - tarmac and concrete surfaces are impermeable - tarmac and concrete surfaces are impermeable and lead to an increase in surface runoff.and lead to an increase in surface runoff.
Flood Control and Flood Control and ManagementManagement
There are a number of ways managing floods:There are a number of ways managing floods: 1. 1. Afforestation Afforestation - planting trees increases interception rates and reduces - planting trees increases interception rates and reduces
surface runoff.surface runoff. 2. 2. Dams and ReservoirsDams and Reservoirs - these hold back and regulate the flow of river - these hold back and regulate the flow of river
water. Can be used as fresh water supply and generation of HEP.water. Can be used as fresh water supply and generation of HEP. 3. 3. Diversion ChannelsDiversion Channels - overflow channels which take surplus water out of a - overflow channels which take surplus water out of a
river in times of flood.river in times of flood. 4. 4. Channel Straitening and DredgingChannel Straitening and Dredging - smoothens the channel to increase - smoothens the channel to increase
the speed (velocity) of the river and get water out of the drainage basin as the speed (velocity) of the river and get water out of the drainage basin as quickly as possible.quickly as possible.
5. 5. Artificial LeveesArtificial Levees - makes river banks higher therefore holding more water. - makes river banks higher therefore holding more water. 66. Culverts. Culverts - semi circular, smooth channels increase velocity and gets - semi circular, smooth channels increase velocity and gets
water away from urban areas as quickly as possible.water away from urban areas as quickly as possible. 7. 7. Revetments and Channel WallsRevetments and Channel Walls - strengthen river banks from erosion. - strengthen river banks from erosion.