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In-Stream Habitat Survey. Modified from ODFW entory/methods.html Quantitative method for assessing habitat.

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Presentation on theme: "In-Stream Habitat Survey. Modified from ODFW entory/methods.html Quantitative method for assessing habitat."— Presentation transcript:

1 In-Stream Habitat Survey

2 Modified from ODFW entory/methods.html 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 1R 2P 3G Unit Number Sequential # starting downstream Unit Type Riffle, glide, or pool

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

5 Unit Types – Riffle

6 Unit Types – Glide GLGlide: 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 Max Depth PTC Depth FLOW

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 LWD TypeDiameterLength Root Wad>6”- Small>6”>10’ Medium>12”>20’ Large>20”>35’  Must be DEAD  Overhanging or in channel

17 Diameter = Circumference  (approx. 3.14) Diameter Circumference

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’ Riffle W = 5’, L = 20’ Pool W = 10’ L = 10’

21 Percent Pool Area Percent Pool Area = 200/300 = 67% Habitat Benchmarks UndesirableBetweenDesirable Pool Area (%) < > 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 Riffle Length/Width = distance btwn pools relative to stream width

23 Pool Frequency Pool Frequency = Distance Between Pools / Channel Width Pool Frequency = 20 / 5 = 4 Pool Riffle W = 5’, L = 20’

24 Pool Frequency Pool Frequency = 20 / 5 = 4 Habitat Benchmarks UndesirableBetweenDesirable Pool Frequency > < 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 Habitat Benchmarks UndesirableBetweenDesirable Small Streams (<23 feet wide) < – 1.5> 1.5 2’ > 1.5’, so Residual Pool Depth = Desirable Residual Pool Depth =2’

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 Pool Riffle W = 5’, D = 0.5’ Habitat Benchmarks UndesirableBetweenDesirable Width to Depth > < 15

30 Riffle – % Gravel If % Gravel = 25%, Rating is Between Habitat Benchmarks UndesBtwnDesir Percent Gravel < > 35

31 Riffle – % Sand-Silt-Organics If % Sand-Silt-Organics = 10%, Rating is Between Habitat Benchmarks UndesBtwnDesir Percent Sand-Silt- Organics > < 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 UndesirableBetweenDesirable Number of Pieces < 1010 – 20> 20 Large Pieces < 11 – 3> 3

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

34 Habitat Benchmarks SHADE (REACH AVERAGE %) U B D Stream Width <40 feet West Side<6060 – 70>70 Northeast<5050 – 60>60 Central-Southeast<4040 – 50>50 Stream Width >40 feet West Side<5050 – 60>60 Northeast<4040 – 50>50 Central-Southeast<3030 – 40>40 94% > 70%


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