Zusammenfassung der Ressource
Water on the land
- The river valley
- Upper course
- STEEP GRADIENT
- V-SHAPED VALLEY
- SHALLOW CHANNEL
- Middle course
- MEDIUM GRADIENT
- GENTLY SLOPING VALLEY SIDES
- DEEPER CHANNEL
- Lower course
- VERY WIDE
- NEARLY FLAT VALLEY
- DEEP CHANNEL
- (a pool goes
from
shallow to
deep as with
a channel)
- REMEMBER: HIGH TO MEDIUM TO LOW (IT
GOES FROM STEEP GRADIENT TO MEDIUM
GRADIENT TO LOW GRADIENT
- EROSION
- VERTICAL EROSION
- -DEEPENS RIVER
CHANNEL/VALLEY
-DOMINANT IN
UPPERCOURSE
- LATERAL = LATER COURSES
VERTICAL = VERY FIRST COURSES
- LATERAL EROSION
- -WIDENS
CHANNEL/VALLEY
-IN MIDDLE +
LOWER
- FOUR STAGES
- 1: HYDRAULIC ACTION
- 2: ABRASION
- 3: ATTRITION
- 4: SOLUTION
- water dissolves rock : limestone + chalk
- DISSOLVE to make a SOLUTION
- rocks smash together and break, edges round off as they rub
- Rocks carried by river rub and wear channel away
- force of a water breaks rock particles away from river channel
- ACTION BY FORCE
- Harry Ate Apple Sorbet
- TRANSPORTATION
- 1: TRACTION
- 2: SALTATION
- 3: SUSPENSION
- 4:SOLUTION
- SOLUBLE materials dissolve in water + are carried along
- SMALL particles (silt + clay) carried by water
- pebble size particles go along river bed by force of water
- LARGE particles pushed along river bed by force of water
- Tracy Saw Susan Sobbing
- DEPOSITION
- River drops eroded material
- When a river SLOWS down
- -LOW WATER
VOLUME IN RIVER
-INCREASED ERODED
MATERIAL IN RIVER
-RIVER REACHES ITS
MOUTH
- WHY??
- FLOODING CASE STUDIES
- CARLISLE, ENGLAND
- CAUSES
- LARGE URBAN AREA = IMPERMEABLE
MATERIALS = INCREASED RUN OFF
- HEAVY RAIN FALL (200mm 36hours)
- PRIMARY EFFECTS: -3 DEATHS
-RIVERS POLLUTED WITH
RUBBISH + SEWAGE
- SECONDARY
EFFECTS: -3000 JOBS
AT RISK
- LONG TERM RESPONSE: HOUSES ON STILTS
- SHORT TERM RESPONSE: CHARITIES GIVE FOOD
- RIVER EDEN
- SOUTH ASIA, BANGLADESH + INDIA
- CAUSES
- MELTING SNOW FROM GLACIERS HIMALAYEN MOUNTAINS
- INCREASED DISCHARGE OF BRAHMAPUTRA
- PEAK DISCHARGE OF BRAHMAPUTRA +
GANGES REACHED AT SAME TIME
- MORE DISCHARGE DOWN STREAM
- PRIMARY EFFECTS: -2000 DEATHS
-RIVERS POLLUTED WITH RUBBISH
+ SEWAGE
- SECONDARY EFFECTS: -4000 SCHOOLS AFFECTED
- LONG TERM RESPONSE: FLOOD DEFENCE SCHEME
- SHORT TERM RESPONSE: EVACUATION
- BRAHMAPUTRA + GANGES