1. In-Stream Habitat Survey
Student Watershed Research Project (SWRP) In-Stream Habitat

2. In-Stream Habitat Survey
Modified from ODFW
Quantitative method for assessing habitat for fish
2 steps to survey:
Data collection
Summary
Measurements are made at the “unit type” level

3. Habitat Units Unit Number Unit Type 1 R 2 P 3 G 3 1 2
~~~~~~
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~~~~~~~~ 1 2
Unit Number
Sequential # starting downstream
Unit Type
Riffle, glide, or pool
Unit Number
Unit Type 1 R 2 P 3 G

4. Unit Types – Riffle
RI Riffle: Fast, turbulent, shallow flow over gravel or cobble substrate.

5. Unit Types – Riffle

6. Unit Types – Glide
GL Glide: Fairly uniform depth and flow with no surface turbulence.
Deeper than riffle, but not deep enough to be a pool.

7. Unit Types – Glide

8. Unit Types – Pool

9. Unit Measurements Length Width and Depth
Wetted Surface
Active Channel
Depth at Pool Tail Crest (pools only)
Channel Shade (left and right side)
Percent Actively Eroding Bank
Percent Undercut Bank

10. Pool Tail Crest
Place where water leaks out of pool (measure at deepest spot)
Measure for POOL units only
FLOW
Max Depth
PTC Depth

11. Shade
Measure using clinometer
90°
80°

12. Substrate Percent (within each unit)
Silt/Organics
Sand
Gravel
Cobble
Boulder
Bedrock
Large Boulder Count (>1.5 ft diameter)

13. Substrate

14. Large Boulders
Large boulders create “pocket water”

15. Large Woody Debris

16. Large Woody Debris Must be DEAD Overhanging or in channel LWD Type
Diameter
Length
Root Wad
>6” -
Small
>10’
Medium
>12”
>20’
Large
>20”
>35’

17. Diameter = Circumference  (approx. 3.14)

18. Habitat Summary Why did we take all those measurements?
The Summary allows us to see whether our stream has desirable habitat for fish

19. Percent Pool Area Percent Pool Area = Pool Area/Reach Area
Pool Area = Length x Width for pool units
Reach Area = Length x Width for ALL units
Pool
Riffle
Percent of stream area which is pool

20. Percent Pool Area Pool Area = (10 x 10) + (10 x 10) = 200
Reach Area = (5 x 20) = 300
Percent Pool Area = 200/300 = 67%
Pool
W = 10’ L = 10’
Pool
W = 10’ L = 10’
Riffle
W = 5’, L = 20’

21. Percent Pool Area Percent Pool Area = 200/300 = 67% Habitat Benchmarks
Undesirable
Between
Desirable
Pool Area (%)
< 10
10-35
> 35
67% > 35%, so Pool Area = Desirable

22. Pool Frequency Pool Frequency = Distance Between Pools / Channel Width
Channel Width = Average width for all units between pools
Pool
Pool
Riffle
Length/Width = distance btwn pools relative to stream width

23. Pool Frequency Pool Frequency = Distance Between Pools / Channel Width
Riffle
W = 5’, L = 20’
Pool
Pool

24. Pool Frequency Pool Frequency = 20 / 5 = 4 Habitat Benchmarks
Undesirable
Between
Desirable
Pool Frequency
> 20
9 - 20
< 8
4 < 8, so Pool Frequency = Desirable

25. Residual Pool Depth
Residual Pool Depth = Max Depth – Pool Tail Crest Depth
Important for low to no flow conditions
Max Depth
PTC Depth

26. Residual Pool Depth
Residual Pool Depth = Max Depth – Pool Tail Crest Depth
Example:
Pool Depth = 3’
Pool Tail Crest = 1’
Residual Pool Depth = 2’

27. Residual Pool Depth Residual Pool Depth = 2’ Habitat Benchmarks
Undesirable
Between
Desirable
Small Streams (<23 feet wide)
< 0.5
0.5 – 1.5
> 1.5
2’ > 1.5’ , so Residual Pool Depth = Desirable

28. Habitat Summary – Riffles
Width to Depth Ratio
Percent Gravel
Percent Sand-Silt-Organics

29. Riffle – Width to Depth Width / Depth = 5 / 0.5 = 10
Habitat Benchmarks
Undesirable
Between
Desirable
Width to Depth
> 30
< 15
Riffle
W = 5’, D = 0.5’
Pool
Pool

30. Riffle – % Gravel If % Gravel = 25%, Rating is Between Undes Btwn
Habitat Benchmarks
Undes
Btwn
Desir
Percent Gravel
< 15
> 35

31. Riffle – % Sand-Silt-Organics
If % Sand-Silt-Organics = 10%, Rating is Between
Habitat Benchmarks
Undes
Btwn
Desir
Percent Sand-Silt-Organics
> 15
8 - 15
< 8
Values for streams with Volcanic Parent Material

32. Habitat Summary - LWD Number of Pieces / 300’ Stream Reach
Large LWD Pieces / 300’ Stream Reach
>20” Diameter and 35’ Length
Habitat Benchmarks
Undesirable
Between
Desirable
Number of Pieces
< 10
10 – 20
> 20
Large Pieces
< 1
1 – 3
> 3
Student Watershed Research Project (SWRP) In-Stream Habitat

33. Habitat Summary Shade (average for entire reach)
Left + Right Bank Shade (degrees) / 180
Final Shade in %
90° + 80° = 170°
170 / 180 = 94%
90°
80°

34. Habitat Benchmarks 94% > 70% SHADE (REACH AVERAGE %) U B D
Stream Width <40 feet
West Side
<60
60 – 70
>70
Northeast
<50
50 – 60
>60
Central-Southeast
<40
40 – 50
>50
Stream Width >40 feet
<30
30 – 40
>40
94% > 70%
Student Watershed Research Project (SWRP) In-Stream Habitat