Use of Stream Habitat Surveys to Predict Rearing Capacity of Juvenile

Steelhead

Steven P. Cramer &

Nicklaus K. Ackerman

S.P. Cramer & Associates, Inc.600 NW Fariss Rd.Gresham, OR 97030www.spcramer.com

Today’s Topics

1. The Unit Characteristic Method: Helping Bridge the Gap in our

Understanding of Habitat and Fish

2. UCM Driving Functions and Justifications

3. Investigating the accuracy of UCMcapacity estimates

Today’s Topics

1. The Unit Characteristic Method: Helping Bridge the Gap in our

Understanding of Habitat and Fish

2. UCM Driving Functions and Justifications

3. Investigating the accuracy of UCMcapacity estimates

The UCM: Helping Bridge the Gap in our Understanding of Habitat and

Fish

Understanding stream capacity is important to fisheries management and conservation.

Stream capacity is related to availability of habitat resources.

The UCM uses relationships between steelhead rearing densities and habitat features, at the life stage that is most limiting to production, to determine a stream’s capacity.

Capacity BottleneckHabitat for summer rearing of parr is

typically limiting

Graph from Ward and Slaney 1993

Today’s Topics

1. The Unit Characteristic Method: Helping Bridge the Gap in our

Understanding of Habitat and Fish

2. UCM Driving Functions and Justifications

3. Investigating the accuracy of UCMcapacity estimates

Functions of the UCM

UnitComposition

Observed Parrdensities by unit

type

RawCapacity

Wood inPools

Boulders inRiffl es

Depth

I nvert.Production

Alkalinity

Turbidity

OverwinterSurvival(Cobble

I nterstices)

SmoltCapacity

Unit Reach Stream

%Fines

Standard Parr Densities• Represent the

capacity of unit types to hold parr.

•Based on observations from fully seeded coastal Oregon streams.

Steelhead

Pool

Glide RapidRiffl

ePoo

lGlide Rapi

dRiffl

e

Parr

/m2

0.00

0.04

0.08

0.12

0.16

0.20 Steelhead(19 Streams)

Cutthroat(30 Streams)

Cover J ohnson et al. 1993

Wood Complexity Rating

1 2 3 4

Parr

/poo

l

2

3

4

5

6

7

8

Wood:In pools and

glides

Boulders:A velocity refuge and

feeding station in riffles

Depth

Depth (m)

0.0 0.4 0.8 1.2 1.6 2.0Pa

rr/m

20.00

0.05

0.10

0.15

0.20

0.25Pools

Riffles

• Steelhead prefer greater depths in pools and riffles because depth is a form of cover.

• Within riffles, usage drops as depths exceed 1 meter because velocities in deep riffles begin to exceed parr preferences.

Food

Eff ects of Turbidity on Stream Production

NTU

0 20 40 60 80 100

% o

f Cle

ar W

ater

Pro

duc

tion

0.0

0.2

0.4

0.6

0.8

1.0

0.1m depth

0.3m depth

0.5m depth

E.

Fk.

W.

Fk.La

ke B

r.

• Riffles produce the drift invertebrates upon which juvenile salmonids feed.

•A stream must be composed of at least 50% riffle to produce enough food for steelhead.

• Turbidity reduces light penetration which in turn reduces primary production.

•Primary production is correlated to invertebrate production which is correlated to fish production.

Fine Sediments in the Substrate

• Fine sediments in the substrate reduce cover by filling in spaces in cobble, and also can reduce drift invertebrate production.

Fish

D

en

sity

% Fines

Graph taken from Bjornn and Reiser (1991)

Excessive Fines

Alkalinity

• Streams in different regions inherently produce different numbers of fish in part due to their geochemical makeup.

• Alkalinity has been shown in the literature to be directly correlated to fish production.

Overwinter Survival• Juvenile steelhead overwinter in the interstices of substrate.• Ample cobble relatively free of fines is crucial to overwinter survival.

Functions of the UCM

UnitComposition

Observed Parrdensities by unit

type

RawCapacity

Wood inPools

Boulders inRiffl es

Depth

I nvert.Production

Alkalinity

Turbidity

OverwinterSurvival(Cobble

I nterstices)

SmoltCapacity

Unit Reach Stream

%Fines

Today’s Topics

1. The Unit Characteristic Method: Helping Bridge the Gap in our Understanding of Habitat and Fish

2. UCM Driving Functions and Justifications

3. Investigating the accuracy of UCMcapacity estimates

Model ValidationCompare model estimates of capacity to

observed production in fully seeded basins.

Oregon

Test BasinsWatershed Area:

26-1,420km2

Anadromous Stream Length:660km

Years of Juvenile Monitoring:5-11

Average Smolt Production:2,100-26,000

Oregon

1991 1993 1995 1997 1999

Parr

(x1000)

0

5

10

15

20

25Tenmile Creek

Little North Fork Wilson River

1998 2000 2002 2004

Sm

olts

(x1000)

0

5

10

15

20

25

1991 1993 1995 1997 1999

Parr

(x1000)

0

2

4

6

8 Cummins Creek

1998 2000 2002 2004

Sm

olts

(x1000)

0

10

20

30

40

50Little Butte Creek

1994 1996 1998 2000 2002 2004

Sm

olts

(x1000)

0

10

20

30

40

50

60

70Hood River Trout Creek

1998 2000 2002 2004

Sm

olts

(x1000)

0

10

20

30

40

50

60

Catherine Creek

1997 1998 1999 2000 2001

Sm

olts

(x1000)

0

5

10

15

20

25

30

35

Catherine Creek not fully seeded

Observed Capacity (x1000)

0 10 20 30 40 50

UCM

Cap

acit

y Est

imat

e (

x1000)

0

10

20

30

40

50

1:1 (Obs = Exp)

Regression

Conclusions1. Model functions reflect relationships

known to exist between steelhead production and habitat.

2. The model incorporates data from standard habitat surveys. Subjectivity is minimized, data are widely available, and model simulations can be done quickly.

3. Testing of UCM predicted capacities indicates model results are typically within +/- 35% of observed capacity.

4. Among the test basins, the model tended to underestimate capacity in smaller basins, and overestimate in larger basins. We will add a channel width variable to account for this.

Additional Uses of UCM1. The UCM may be used to estimate

changes in capacity that result from habitat alterations.

2. The UCM can be used to examine how changes in low flow affect stream capacity. This use is soon to be tested and published.

3. The UCM may be used for other species. A spring Chinook model has been developed and applied, but has not yet been validated.