Rivers Flashcards
EROSION processes
vertical erosion lateral erosion headward erosion abrasion attrition hydraulic action cavitation corrosion
TRANSPORT processes
traction saltation suspension solution
what affects channel flow and velocity?
- type of flow 2. channel shape 3. channel roughness
EROSION landforms
waterfall/gorge v shaped valley
DEPOSITION landforms
delta
factors affecting EROSION
LOAD - the heavier and sharper the load, the more erosion VELOCITY - greater the velocity, the greater the potential for erosion GRADIENT - increased gradient increases rate of erosion GEOLOGY - weak unconsolidated rocks are easily eroded compared to consolidated rocks. pH - rates of solution are increased with more acidic water HUMAN IMPACT - deforestation, dams and bridges interfere with the natural flow of river and often increase the rate of erosion
DEPOSITION landforms
deltas braided channels levees
factors affecting EROSION
LOAD - the heavier and sharper the load, the more erosion VELOCITY - greater the velocity, the greater the potential for erosion GRADIENT - increased gradient increases rate of erosion GEOLOGY - weak unconsolidated rocks are easily eroded compared to consolidated rocks. pH - rates of solution are increased with more acidic water HUMAN IMPACT - deforestation, dams and bridges interfere with the natural flow of river and often increase the rate of erosion
EROSION and DEPOSITION landforms
meanders oxbow lakes
what is LATERAL EROSION?
erosion of the sides of a river bank (widening)
what is VERTICAL EROSION?
erosion of river bed (deepening)
what is HEADWARD EROSION?
increases length of channel
waterfall PROCESSES
HYDRAULIC ACTION ABRASION
WHERE does a waterfall form?
UPPER COURSE where there is a layer of resistant rock above a layer of weaker rock
HOW does a waterfall form?
weaker rock is undercut by HYDRAULIC ACTION and ABRASION in the process of enlarging the plunge pool at the base of the waterfall. Collapse and retreat then occur, and the waterfall travels upstream, leaving a gorge behind.
what is a GORGE?
a narrow steep sided valley
HOW is a gorge formed?
- left behind following waterfall retreat 2. opening up of a fault line
OPPORTUNITIES of waterfalls and gorges
HEP tourism easy to create dams
OPPORTUNITIES of waterfalls and gorges
HEP tourism easy to create dams
meander PROCESSES
EROSION of outer bank resulting in RIVER CLIFFS DEPOSITION at inner bank forming POINT BARS/SLIP OFF SLOPES
oxbow PROCESSES
result from LATERAL EROSION (and DEPOSITION (closing off the lake from river) caused by centrifugal forces.
delta PROCESSES
Sediment is DEPOSITED due to FLOCCULATION.
what is FLOCCULATION?
the process in which clay and silt particles combine when fresh water mixes with the salt water. the heavier particles sink more rapidly.
