Between bends and their deeper Pools are shallower parts of a stream called a riffle.On the outer side of a bend there is often a deep area called a pool. This is another riffle-a shallow area between pools. Riffles are areas where sediment is deposited and temporairy stored.

On the inside of a bend is a LEFT point bar--an area of sediment deposition. Here the stream moves slowly and drops some of its sediment load.

On the inside of this bend is a RIGHT point bar--also an area of sand and gravel deposition. The line connecting the deepest part of the channel is called the thalweg.

Sure! The discharge determined on the prior page is a little less than 0.9 cubic meters per second. The calculation was very easy: a product of cross sectional area and average velocity. But that's for our hypothetical stream with a rectangular cross-section and uniform velocity from bank to bank.

Real-world streams are not that simple. Cross sections are irregular and a stream's flowing water is slowed by the frictional effects of the sides of the channel.

Also, a more complex stream commonly flows in sinuous paths called meanders.

Meanders are a product of the stability of stream banks, which are controlled by the vegetation on the bank, the size of the sediment within the banks, and the power of the water in the stream (its discharge).

The left illustration below has two straight lines that cross the stream at meander bends. The distance between those lines is called the meander wavelength.

Riffles (where the channel is straight) and point bars (on the inside of a meander curve) are places where sediment is being deposited and temporarily stored. Pools are places where sediment is being eroded or removed.

Move your mouse cursor over the points marked "X" to find descriptions of some of the features of a meandering stream.. Then respond to the questions below by matching the red letter with its corresponding term.

The faster-moving stream along the outside of a bend erodes a cut bank.

Herd Creek, Idaho: View in the downstream direction during low discharge.

1. riffle
A B C D E F G

5. cutbank on left bank
A B C D E F G

2. upstream pool
A B C D E F G

6. point bar on right bank
A B C D E F G

3. downstream pool
A B C D E F G

7. point bar on left bank
A B C D E F G

4. cutbank on right bank
A B C D E F G