The Fluvial Process

The Fluvial Process

Stream Profiles

in upper reaches ("youthful") streams
- straight and incised by downcutting & steep gradient
in lower reaches -
kickpoints and waterfalls -

Lower Reaches of a River

in lower reaches - meandering stream and floodplain
- sometimes referred to as "mature" streams
significantly reduced gradient
- more deposition, limited incising, especially with flat gradient

flood plain shows meandering stream

Characteristics of a flood plain:

cut banks -
point bars (sand bars) -
oxbow lakes -

natural levees -

levee

back swamps -
bluffs - demarcate furthest extent of floodplain
- Mississippi Valley

goosenecks

Delta’s and Rejuvenation

broad triangular shape, such as Nile River (Greek letter)
- flat gradient and slow stream velocity
- reduced load capacity and drops much of its load
  - deposition occurs

maze of sediment blocks outlets

some rivers become "rejuvenated" and entrenched
- uplift and downcutting at same time
  - Goosenecks of the San Juan River in Utah
some rivers were there first before mountain building
- compression, folding, and slow uplift
  - known as andecendent streams

Tiger Leaping Gorge, Yunnan, China

Physical Index