Dudley Reiser, Eric Jeanes, Stuart Beck,Catherine MorelloR2 Resource Consultants

and Dwayne Paige and Heidy BarnettSeattle Public Utilities

1

Chester Morse Lake –major water supply for City of Seattle – also some limited hydropower generation

Major tributaries –Cedar and Rex rivers

2

Rex River

Cedar River

Chester Morse Lake

Cedar watershed supports Adfluvial populations of bull trout (“threatened” under ESA)

Estimated population

of bull trout: 3100 adults

Pygmy whitefish (native) and rainbow trout (introduced) also present

3

Reservoir levels fluctuate seasonally

Low levels create riverine habitats in lower reaches of rivers –conducive for spawning

Higher levels –progressive upstream shift from riverine to lacustrine habitats –potential reddinundation

4

Redd inundation

1/1 4/1 7/1 10/1 1/1

Flo

w (

cfs)

0

1000

2000

3000

4000

5000

6000

7000

Maximum

Median

Minimum

Cedar River Upstream

from Chester Morse Lake

1946 to 2006

Spawning

Incubation

Incubation

Bull trout spawning on rising limb of hydrograph

1/1 4/1 7/1 10/1 1/1

Wate

r S

urf

ace

Ele

vati

on

(fe

et)

1520

1530

1540

1550

1560

1570

1580

Maximum

Median

Minimum

Chester Morse Lake

1979 to 2006

Spawning

Incubation

Incubation

Bull trout spawning when reservoir levels low

Suitable depths and velocities

Intragravel velocities &

downwelling

Clean gravels = low fine

sediments (

8

Lower redds 10-15 ft deep

Assessment of potential bull trout “take” required in HCP

9

ENDANGERED SPECIES ACT

- SECTION 7

BIOLOGICAL OPINION

UNLISTED SPECIES

ANALYSIS, AND SECTION 10

FINDINGS

for proposed issuance of a

Section 10 Incidental Take

Permit to the City of Seattle,

Seattle Public Utility, for the

Cedar River Watershed

Habitat Conservation Plan

Effects of reservoir fluctuations on bull trout spawning and egg survival: SPECIFICALLY – effects of redd inundation Ho – Higher egg mortality related to longer periods of

redd inundation

Estimate potential “take” (if possible)

Define causal mechanisms of take

Integrate results into “risk-averse” operational plan

10

Remote spawning of bull trout Artificial redds constructed within zone of reservoir

influence Monitor redds and “controls” for survival and

emergence Collect ancillary data Sediment Water temperature DO

Comparisons of Survival to emergence (STE) vs Days of inundation

11

12

Capture

13

Spawn – Fertilize – Water Harden

Cedar River

5 females spawned (400-528 mm FL)

2 males (460-520 mm FL)

Rex River

5 females spawned (453-563 mm FL)

1 male (546mm FL)

Weights – range 650 – 1500 gm

14

15

Egg Planting

16

• Filled with clean gravel

•Duct tape on bottom

•50 embryos per box

•4 boxes per redd

•Colored string attached

for relocation

17

N=23

Approximate upper

extent of inundation

18

Approximate upper

extent of inundation

N=17

19

CONTROLS

9/1/06 10/1/06 11/1/06 12/1/06 1/1/07

Ch

este

r M

ors

e L

ak

e

Wate

r S

urf

ace

Ele

vati

on

(fe

et, N

GV

D29

)

1520

1530

1540

1550

1560

1570

1580

Ced

ar

Riv

er

Dail

y-A

ver

ag

ed F

low

(cfs

)

0

1000

2000

3000

4000

5000

6000

7000

Water surface elevation (reported at 8:00 AM)

Flow at USGS Gage 12115000

100 YEAR

FLOOD

Eggs

planted

Scour and dislodgement

Deposition and covering

Channel re-alignment

21

TESTS COMPROMISED

22

N=23

Approximate upper

extent of inundation

76% survival

Not Found/Recovered

4% survival

23

Approximate upper

extent of inundation

N=17

Not Found/Recovered

24

PRELIMINARY POSTULATES:

•Observations

•Some physical data

•Some biological data

25

OBSERVATIONS

Surficial sediment

deposition noticeable

at reservoir – river interface

26

Site

1 2 3 4 5 6 7 8 9

Per

cen

t F

ines

les

s th

an

0.8

4 m

m

0

10

20

30

40

UPSTREAM

Patterns of Sediment Deposition

PHYSICAL DATA ?

Riverine - Low sediment levels = high egg

survival

27

Lacustrine - High sediment levels = low egg survival

Operations - Static

Operations - Dynamic

RISK

30

Risk of DEPOSITION

& ENTOMBMENT

Risk of low DO

& App Vel

Combinations of River Flow and

Reservoir Levels are complicated

31

9/1/06 10/1/06 11/1/06 12/1/06 1/1/07

Ch

este

r M

ors

e L

ak

e

Wate

r S

urf

ace

Ele

vati

on

(fe

et, N

GV

D29

)

1520

1530

1540

1550

1560

1570

1580

Ced

ar

Riv

er

Da

ily

-Av

era

ged

Flo

w (

cfs

)

0

1000

2000

3000

4000

5000

6000

7000

Water surface elevation (reported at 8:00 AM)

Flow at USGS Gage 12115000

32

QUESTIONS