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

In-Stream Habitat Survey Modified from ODFW http://oregonstate.edu/Dept/ODFW/freshwater/inventory/methods.html Quantitative method for assessing habitat for fish 2 steps to survey: Data collection Summary Measurements are made at the “unit type” level

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

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

Unit Types – Riffle

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.

Unit Types – Glide

Unit Types – Pool

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

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

Shade Measure using clinometer 90° 80°

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

Substrate

Large Boulders Large boulders create “pocket water”

Large Woody Debris

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’

Diameter = Circumference  (approx. 3.14)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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