Types Of Stream Channels

Question 0

Meandering channels: An ox-bow lake is

Answer 0

An abandoned meander bend.

Question 1

Meandering channels: (3)

Answer 1

Sinuosity of >1.5
Cut through deposits of fine clay and silt.
Channel and floodplain have moderate gradients.

Question 2

Meandering channels: Meander is a sine-generated curve,

Answer 2

It has the smallest variation in the change of direction. The stream does the least amount of work in turning.

Question 3

Meandering channels: River minimises resistance to flow and

Answer 3

Spreads energy as evenly as possible along its course.

Question 4

Meandering channels: The speed of the moving water isn’t the same everywhere,

Answer 4

On a bend, the zone of high speed is at the outside of the channel.

The water at depth flows slower than the surface water because of the friction from the channel bed.

Question 5

Meandering channels: Helical flow - Fast moving water

Answer 5

Builds up against the outside bank, creating large pressure than the water at depth. The pressure gradient causes the surface water to sink and return to the inner bank, along the river bed.

Question 6

Meandering channels: Helical flow - Erosion occurs on the

Answer 6

Outside of the bend, deposition on the inside bend. This produces point bars on the inside bend.

The point of erosion occurs slightly downstream of meander midpoint, resulting in the meander widening in that direction.

Question 7

Sinuosity: A measure of

Answer 7

How straight a stream is.

Question 8

Sinuosity: is related to

Answer 8

Gradient and composition of stream bed.

Question 9

Sinuosity (S) =

Answer 9

Length of stream channel / Straight distance

Question 10

Braided channels: Material eroded form banks is

Answer 10

Transported a short distance then deposited as a bar. The bar is an obstacle to water flow and eventually builds up above the water surface.

Question 11

Braided channels: Easily eroded banks,

Answer 11

Pushed back due to lateral erosion during floods. The stream widens, becomes shallower and the water velocity drops.

Question 12

Braided channels: Have steep

Answer 12

River gradients, with coarse, uncohesive bank sediments.

Question 13

Braided channels:

Braiding index =

Answer 13

Sum of length of bars in stream section / length of stream section (L)

Question 14

Straight channels: (5)

Answer 14

Steep banks, 
Sinuosity of < 1.5,
Unusual, 
Gentle gradient, 
Fine banks of silt and clay.

Question 15

Straight channels: Absence of

Answer 15

Significant downstream water velocity.

Question 16

Straight channels: Thalweg - The line of

Answer 16

Maximum depth and strongest current, usually winds from one side to the other.

Question 17

Straight channels: Thalweg - As it approaches one side

Answer 17

Of the bank, sand and mud deposits accumulate on the opposite side.