2: Rivers Flashcards
Drainage Basins
The entire geographical area drained by a river and its tributaries.
River Channel
A channel is a type of landform consisting of the outline of a path of relatively shallow and narrow body of fluid, most commonly the confine of a river, river delta, or strait.
____ the elevation the ____ the gradient
High; High
Low; Low
Discharge
the volume of water that moves down the river per unit time
The continuity equation
Q = V x A
Q: Discharge (meters or feet cubed/seconds)
V: Current Velocity (meters or feet/seconds)
A: channel cross-sectional area (meters or feet squared)
List of sediments in rivers (3)
Bed Load
Suspended load
Dissolved load
Which sediment load is the greatest total
Suspended load is greater than 90% of total sediment
Knickpoints
A location of a river or channel where there is a sharp change in channel slope
Developed at resistant rock units or fault scarps
Migrate upstream
Changes in streams with smooth profile
Future stream elevation is lowered
Changes in land use: forest to row crops
Soil erosion; sediment load to stream increases
Sediment deposited along stream, increasing the slope
After significant steepening of the profile, stream will pick up energy and start to erode back down
Changes in land use: row crops to forest
Sediment load to stream decreases
Erosion of channel lowers slope along stream
After significant lowering of the profile, stream will lose energy and start depositing again
Cross-section of stream in central Georgia
Pre-1800’s: forest
1800’s-1930: agriculture
Post-1930: forest
Effects of dams
Stream profile after the dam will sink further because of the lack of water.
Glen Canyon Dam, Arizona will be dry on the otherside in how many years?
688
Channel patterns of river systems
Straight channels
Braided rivers
Meandering rivers
