last minute river revision formation of landscapes

how is a waterfall formed? (4 stages)

1. water runs over alternating bands of soft rock and hard rock
   erosion begins with hydraulic action, abrasion, solution

2. soft rock eroded by hydraulic action
   soft rock less resistant than hard rock
   overtime soft rock undercuts hard rock

3. hard rock unsupported + collapses into riverbed (rockfall)
   fallen rock flow downstream or erodes by abrasion
   a deep hollow called plunge pool is formed

4. erosion repeats + waterfall retreats
   a steep-sided gorge left behind

how is a levee formed? (3 stages)

1. before flood - water held within channel

2. during flood - water passes over surface + increased friction occurs resulting in slower flow
   heavier material deposited first in closest point to river
   this bc water has no energy to transport material
   finer thinner sediment transported + deposited further away from river

3. levee gradually gets higher after successive floods

how do meanders + oxbow lakes form (6 steps)

1. water flows over land, water swings to outside of river, where less friction

2. when river erodes river bank, a bend occurs = meander

3. inside of bend flow = slower so gets deposits of sediment

4. neck is narrower

5. when neck of river breaks through, takes on shortest route = straight course

6. look is sealed off as result of deposition = AKA oxbow lake

how are interlocking spurs formed? (3 stages)

1. very steep v-shaped valley
   river takes up most of valley floor
   hard rock = hard to weather

2. freeze thaw weathering widens valley a bit
   but valley still quite steep

3. spurs of high land enter valley floor from alternate sides of valley = interlocking spurs