Channel Assessment And Riparian Assessment

Question 1

What is a streams reach?

Answer 1

Approx 100m section that is relatively uniform.
Homogenous in channel pattern and discharge

Question 2

How do we define a stream?

Answer 2

Evidence of a scoured area
Evidence of alluvium.
Has to be at least 100m

Question 3

What is a stream break that ends a reach?

Answer 3

A tributary intersecting
Straight to sinuous
Changes in: sediments supply, riparian area, strea,bed or bank material, channel confinement, gradient

Question 4

What are the steps to do channel assessments?

Answer 4

1) Divide channel into series of reaches.
2) Divide reach into 5 even segments to measure bank fall width
3) measure depth at 5 locations along the reach
4) you measure the d95 (largest sediment particle) at 5 locations evenly spaced along the reach
5) measure the channel gradient/slope (be as far apart as possible)

Question 5

What are different morphology types?

Answer 5

Riffle pool = Low gradient stream. Has a meander pattern. Often large woody debris. (SPr, SPb, SPb -w)
Step pool= rock pools in steps. Between each rock step is a pool.
Cascade = series of continuous flow, pools are random if they exist.

Question 6

What are factors in assessing channel stability?

Answer 6

Degrading = scouring/cutting into the bed. Increases in volume, velocity and slope. Typically upper reaches
Stable = expected rate of change
Aggrading = depositing load, decreased volume, decreased velocity, lower reaches.

Question 7

What is a riparian habitat?

Answer 7

Areas next to banks of streams/lakes/wetlands. High moisture content supports vegetation.

Question 8

What important functions do riparian areas have?

Answer 8

Protects water quality
Stabilizes streambanks
Regulates stream temperatures
Source of woody debris to the stream channel
Source of fish food
Highest biodiversity of plants and animals
Critical habitats

Question 9

What are the different classes of streams?

Answer 9

If it is a fish stream or community watershed:
If average channel width is over 20M = S1
If between 5 and 20m = s2
If 1.5 to 5m = s3
If less than 1.5m = s4

If there are no fish or not community watershed
Greater than 3m = s5
Less than 3m = s6

Question 10

How is bank fall width determined in a channel assessment to classify a stream?

Answer 10

5 evenly spaced measurements of theQ2, bankfall width
Add them all up and divide by number of measurements to get an average.

Question 11

What are the classes of lakes for riparian management?

Answer 11

L1 to L4
If it’s greater than 5ha = L1
Otherwise, classification depends on the biogeoclimatic zone to classify