ior to Marmot Dam Removal on the Sandy River, Oregonmarmot/Long_Poster_Aug_2007.pdf · 2009. 8....
1
Summer Undergraduate Research Optimal Grain Size Diameters for Salmon Spawning Habitat Prior to Marmot Dam Removal on the Sandy River, Oregon Michaela Long, University of Arizona Mentors: Dr. Peter Wilcock, Chuck Podolak, Johns Hopkins University N A T I O N A L C E N T E R F O R E A R T H - S U R F A C E D Y N A M I C S St. Anthony Falls Laboratory Objectives One of the primary purposes of dam removal is to restore the stream to the natural condition with emphasis on aiding natural biological habitats. Through observation of sediment transport, one can predict the suitability of salmon spawning. Although there are several factors that contribute to determining optimal spawning habitat suitability, grain-size distribution of the riverbed is the most significant for analysis of river conditions before and after dam removal. The distribution of the sediment following a massive load of sediment transport will determine the sustenance of the salmon species during dam removal and ultimately determine the success of dam removal projects. Methods To evaluate pre-dam removal sediment composition, I generated facies maps which are maps of numerous patches of sediment with the homogeneous characteristics. I performed pebble counts of the area to determine the grain-size distribution of the riverbed across several reaches downstream. I took existing fish literature in fisheries journals to find salmon spawning areas. The locations mapped out in fisheries journals will provide a foundation for which to narrow search for redds for each particular species of salmonids. Although neither of the salmon species were spawning at the time of the field work, I observed the grain-size diameters of the gravel where redds are expected to be found during spawning season and I produced facies maps in these areas. Abstract The purpose of the Marmot Dam removal at the Sandy River is to improve habitat connectivity for salmonid population and to restore natural streamflow downstream of the dam. The nature of salmon spawning efforts depends significantly on sediment composition of the riverbed. The anticipated sediment transport initiated by dam removal is expected to affect salmon habitat across different reaches of the river, with the degree of severity depending on location relative to the dam and sediment composition. How will the massive amount of sediment transport affect salmon spawning? Which grain sizes are optimal for spawning? How are these particular grain-sizes distributed along the river? How will this sediment transport following dam removal? Data collection consists of using Wolman’s pebble- count method to determine the grain-size distribution (GSD) across several river reaches. Comparisons of grain-size diameters to salmon habitat will determine the optimal grain-size for salmon spawning efforts. Results show that the average grain-size of areas with greater salmon spawning activity is a gravel and cobble composition with diameters ranging between 16mm and 45mm. These results will further be used to detect change in riverbed composition over the course of the next 5-10 years and how dam removal affects salmonid habitat. Dam removal will aid the salmon populations by significantly restoring the stream to its natural conditions. Theoretically, the river may never return to its natural, pristine conditions due to the long-term adverse effects of dam construction on the structure and natural functions of the river ecosystem. However, dam removal offers the best attempt at salvaging the numerous ecological communities. Immediately following dam removal, the conditions of the bed channel is expected to be disastrous for fish populations due to the relatively massive sediment transport downstream. The dissolved load, consisting of material that is transported in solution, is predicted to be highly unsuitable to salmon biological functions ultimately causing mortality. In addition, the bed channel is expected to be highly unstable for several years following dam removal directly impacting salmon habitat. Eventually, the bed channel will flatten out over time and make the best attempt to restore to pre-dam conditions supporting aquatic ecosystems. Pacific salmonids are critical to maintaining nutrients in the river ecosystem. They are anadromous; they spend the beginning of their lives in freshwater and migrate to the sea where they spend a majority of their adult lives. Eventually, they return to the exact streams where they were hatched in freshwater to reproduce and die. Thus, migration passages are highly significant to salmon development and reproduction. During their period in saltwater, they eat ravenously to store fat and no longer feed in the river. When the female spawns, she buries redds, or nests in the gravel. Salmon typically deposit up to a thousand eggs in each redd. Upon fertilization, the female then covers each redd with gravel and deteriorates while guarding the nest. Salmon corpses provide plentiful nutrients to the river. There are several species that inhabit the Sandy River. The coho salmon (Oncorhynchus kisutch) is the species under investigation in the field due to its high population. The Sandy river consists of salmon that have been raised at the fisheries and then released into the river; wild salmon are not under experimentation. The spring Chinook, summer Steelhead, and Coho salmon spawn upstream relative to the dam across several reaches of the river. The Fall Chinook spawn downstream relative to the dam. Winter Steelhead spawn both upstream and downstream of the river relative to the dam. All salmonids spawn far upstream and downstream from the Marmot dam. However, the Chinook salmon have secondary spawning areas just above the Marmot dam, thus these species may be the most affected as a result of the sediment transport in the reservoir. Grain Size Distribution 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10 100 1000 10000 diameter (mm) % finer A B1 B2 OB Total Results Following 3 weeks of field observations and study at the Sandy River, Oregon, the nature and suitability of salmon spawning habitat was evaluated and mapped across several reaches downstream of Marmot Dam. The optimal grain size diameter for salmon spawning efforts in the Sandy River was determined to range between the diameters of 20mm and 47mm. The ideal areas for spawning habitat was based on existing fish literature gathered by the forest services. There was considerable focus on side channels and areas with minimal human activity and low discharge. Acknowledgements I would like to thank Dr. Peter Wilcock and Chuck Podolak at Johns Hopkins University. I would also like to thank Karen Hill and Jeff Marr for the their invaluable guidance. I would like to thank the National Center for Earth-Surface Dynamics (NCED) and St. Anthony Falls Laboratory (SAFL). Discussion The Marmot Dam removal research project will continue into next year. Further research will be conducted to determine change detection in the river bed following a massive load of sediment transport downstream from the dam. This mapping effort was conducted to ensure a deeper understanding of the biological impact of stream restoration. In effort to determine the optimal grain size for spawning habitat, the downstream reach of the river was meticulously mapped even in areas with no spawning suitability. This data will provide a basis to detect the exact change in the geomorphology of the river and can be used in future dam construction and removal projects. Marmot Dam before removal. The Sandy River at Oxbow Park, just one hour east of Portland. Coho Salmon Redds embedded in gravel. Facies Maps at Oxbow Park where significant spawning activity occurs in the fall. Pebble Counting along the riverbank. Background The construction of the Marmot Dam forces several disadvantages to the salmonid population of the Sandy River. Dams alter the natural migration passages in the upstream direction. Dams negatively modify upstream and downstream aquatic environments, including: thermal stratification of the reservoir; downstream flow alteration and termination of inundation of downstream floodplains; sediment and nutrient trapping in reservoirs.
Transcript of ior to Marmot Dam Removal on the Sandy River, Oregonmarmot/Long_Poster_Aug_2007.pdf · 2009. 8....
Sum
mer
Und
ergr
adua
te R
esea
rch
Opt
imal
Gra
in S
ize
Dia
met
ers f
or S
alm
on S
paw
ning
Hab
itat P
rior t
o M
arm
ot D
am R
emov
al o
n th
e Sa
ndy
Riv
er, O
rego
nM
icha
ela
Long
, Uni
vers
ity o
f Ari
zona
Men
tors
: Dr.
Pete
r Wilc
ock,
Chu
ck P
odol
ak, J
ohns
Hop
kins
Uni
vers
ity
N
A
T
I O
N
A
L
C
E
N
T
E R
F O
R
E A
R
T
H
-
S U
R
F
A
C
E
D
Y
N
A
M
I C
S
St.
Ant
hony
Fal
ls L
abor
ator
y
Obj
ectiv
esO
ne o
f the
pri
mar
y pu
rpos
es o
f dam
rem
oval
is to
rest
ore
the
stre
am to
the
natu
ral c
ondi
tion
with
em
phas
is on
aid
ing
natu
ral b
iolo
gica
l hab
itats
. Thr
ough
obs
erva
tion
of se
dim
ent t
rans
port
, one
can
pr
edic
t the
suita
bilit
y of
salm
on sp
awni
ng. A
lthou
gh th
ere
are
seve
ral f
acto
rs th
at c
ontr
ibut
e to
de
term
inin
g op
timal
spaw
ning
hab
itat s
uita
bilit
y, g
rain
-siz
e di
stri
butio
n of
the
rive
rbed
is th
e m
ost
signi
fican
t for
ana
lysis
of r
iver
con
ditio
ns b
efor
e an
d af
ter d
am re
mov
al. T
he d
istri
butio
n of
the
sedi
men
t fol
low
ing
a m
assiv
e lo
ad o
f sed
imen
t tra
nspo
rt w
ill d
eter
min
e th
e su
sten
ance
of t
he sa
lmon
sp
ecie
s dur
ing
dam
rem
oval
and
ulti
mat
ely
dete
rmin
e th
e su
cces
s of d
am re
mov
al p
roje
cts.
Met
hods
To e
valu
ate
pre-
dam
rem
oval
sedi
men
t com
posit
ion,
I ge
nera
ted
faci
esm
aps w
hich
are
map
s of n
umer
ous
patc
hes o
f sed
imen
t with
the
hom
ogen
eous
cha
ract
erist
ics.
I per
form
ed p
ebbl
e co
unts
of t
he a
rea
to
dete
rmin
e th
e gr
ain-
size
dist
ribu
tion
of th
e ri
verb
ed a
cros
s sev
eral
reac
hes d
owns
trea
m. I
took
exi
stin
g fis
h lit
erat
ure
in fi
sher
ies j
ourn
als t
o fin
d sa
lmon
spaw
ning
are
as. T
he lo
catio
ns m
appe
d ou
t in
fishe
ries
jo
urna
ls w
ill p
rovi
de a
foun
datio
n fo
r whi
ch to
nar
row
sear
ch fo
r red
dsfo
r eac
h pa
rtic
ular
spec
ies o
f sa
lmon
ids.
Alth
ough
nei
ther
of t
he sa
lmon
spec
ies w
ere
spaw
ning
at t
he ti
me
of th
e fie
ld w
ork,
I ob
serv
ed
the
grai
n-siz
e di
amet
ers o
f the
gra
vel w
here
redd
sare
exp
ecte
d to
be
foun
d du
ring
spaw
ning
seas
on a
nd I
prod
uced
faci
esm
aps i
n th
ese
area
s.
Abs
trac
tTh
e pu
rpos
e of
the
Mar
mot
Dam
rem
oval
at t
he S
andy
Riv
er is
to im
prov
e ha
bita
t con
nect
ivity
for
salm
onid
popu
latio
n an
d to
rest
ore
natu
ral s
trea
mflo
wdo
wns
trea
m o
f the
dam
. The
nat
ure
of sa
lmon
sp
awni
ng e
ffort
s dep
ends
sign
ifica
ntly
on
sedi
men
t com
posit
ion
of th
e ri
verb
ed. T
he a
ntic
ipat
ed
sedi
men
t tra
nspo
rt in
itiat
ed b
y da
m re
mov
al is
exp
ecte
d to
affe
ct sa
lmon
hab
itat a
cros
s diff
eren
t rea
ches
of
the
rive
r, w
ith th
e de
gree
of s
ever
ity d
epen
ding
on
loca
tion
rela
tive
to th
e da
m a
nd se
dim
ent
com
posit
ion.
How
will
the
mas
sive
amou
nt o
f sed
imen
t tra
nspo
rt a
ffect
salm
on sp
awni
ng? W
hich
gra
in
sizes
are
opt
imal
for s
paw
ning
? How
are
thes
e pa
rtic
ular
gra
in-s
izes
dist
ribu
ted
alon
g th
e ri
ver?
How
w
ill th
is se
dim
ent t
rans
port
follo
win
g da
m re
mov
al?
Dat
a co
llect
ion
cons
ists o
f usin
g W
olm
an’s
pebb
le-
coun
t met
hod
to d
eter
min
e th
e gr
ain-
size
dist
ribu
tion
(GSD
) acr
oss s
ever
al ri
ver r
each
es. C
ompa
riso
ns
of g
rain
-siz
e di
amet
ers t
o sa
lmon
hab
itat w
ill d
eter
min
e th
e op
timal
gra
in-s
ize
for s
alm
on sp
awni
ng
effo
rts.
Res
ults
show
that
the
aver
age
grai
n-siz
e of
are
as w
ith g
reat
er sa
lmon
spaw
ning
act
ivity
is a
gr
avel
and
cob
ble
com
posit
ion
with
dia
met
ers r
angi
ng b
etw
een
16m
m a
nd 4
5mm
. The
se re
sults
will
fu
rthe
r be
used
to d
etec
t cha
nge
in ri
verb
ed c
ompo
sitio
n ov
er th
e co
urse
of t
he n
ext 5
-10
year
s and
how
da
m re
mov
al a
ffect
s sal
mon
idha
bita
t.
Dam
rem
oval
will
aid
the
salm
on p
opul
atio
ns b
y sig
nific
antly
rest
orin
g th
e st
ream
to it
s nat
ural
co
nditi
ons.
Theo
retic
ally
, the
rive
r may
nev
er re
turn
to it
s nat
ural
, pri
stin
e co
nditi
ons d
ue to
the
long
-ter
m a
dver
se e
ffect
s of d
am c
onst
ruct
ion
on th
e st
ruct
ure
and
natu
ral f
unct
ions
of t
he ri
ver
ecos
yste
m. H
owev
er, d
am re
mov
al o
ffers
the
best
att
empt
at s
alva
ging
the
num
erou
s eco
logi
cal
com
mun
ities
. Im
med
iate
ly fo
llow
ing
dam
rem
oval
, the
con
ditio
ns o
f the
bed
cha
nnel
is e
xpec
ted
to
be d
isast
rous
for f
ish p
opul
atio
ns d
ue to
the
rela
tivel
y m
assiv
ese
dim
ent t
rans
port
dow
nstr
eam
. The
di
ssol
ved
load
, con
sistin
g of
mat
eria
l tha
t is t
rans
port
ed in
solu
tion,
is p
redi
cted
to b
e hi
ghly
un
suita
ble
to sa
lmon
bio
logi
cal f
unct
ions
ulti
mat
ely
caus
ing
mor
talit
y. In
add
ition
, the
bed
cha
nnel
is
expe
cted
to b
e hi
ghly
uns
tabl
e fo
r sev
eral
yea
rs fo
llow
ing
dam
rem
oval
dir
ectly
impa
ctin
g sa
lmon
ha
bita
t. Ev
entu
ally
, the
bed
cha
nnel
will
flat
ten
out o
ver t
ime
and
mak
e th
e be
st a
ttem
pt to
rest
ore
to p
re-d
am c
ondi
tions
supp
ortin
g aq
uatic
eco
syst
ems.
Paci
fic sa
lmon
idsa
re c
ritic
al to
mai
ntai
ning
nut
rien
ts in
the
rive
r eco
syst
em. T
hey
are
anad
rom
ous;
they
sp
end
the
begi
nnin
g of
thei
r liv
es in
fres
hwat
er a
nd m
igra
te to
the
sea
whe
re th
ey sp
end
a m
ajor
ity o
f th
eir a
dult
lives
. Eve
ntua
lly, t
hey
retu
rn to
the
exac
t str
eam
s whe
re th
ey w
ere
hatc
hed
in fr
eshw
ater
to
repr
oduc
e an
d di
e. T
hus,
mig
ratio
n pa
ssag
es a
re h
ighl
y sig
nific
ant t
o sa
lmon
dev
elop
men
t and
re
prod
uctio
n. D
urin
g th
eir p
erio
d in
saltw
ater
, the
y ea
t rav
enou
sly to
stor
e fa
t and
no
long
er fe
ed in
the
rive
r. W
hen
the
fem
ale
spaw
ns, s
he b
urie
s red
ds, o
r nes
ts in
the
grav
el. S
alm
on ty
pica
lly d
epos
it up
to a
th
ousa
nd e
ggs i
n ea
ch re
dd. U
pon
fert
iliza
tion,
the
fem
ale
then
cov
ers e
ach
redd
with
gra
vel a
nd
dete
rior
ates
whi
le g
uard
ing
the
nest
. Sal
mon
cor
pses
pro
vide
ple
ntifu
l nut
rien
ts to
the
rive
r.
Ther
e ar
e se
vera
l spe
cies
that
inha
bit t
he S
andy
Riv
er. T
he c
oho
salm
on (O
ncor
hync
husk
isutc
h) is
the
spec
ies u
nder
inve
stig
atio
n in
th
e fie
ld d
ue to
its h
igh
popu
latio
n. T
he S
andy
rive
r con
sists
of
salm
on th
at h
ave
been
raise
d at
the
fishe
ries
and
then
rele
ased
into
th
e ri
ver;
wild
salm
on a
re n
ot u
nder
exp
erim
enta
tion.
The
spri
ngCh
inoo
k, su
mm
er S
teel
head
, and
Coh
o sa
lmon
spaw
n up
stre
am
rela
tive
to th
e da
m a
cros
s sev
eral
reac
hes o
f the
rive
r. Th
e Fa
ll Ch
inoo
k sp
awn
dow
nstr
eam
rela
tive
to th
e da
m. W
inte
r Ste
elhe
ad
spaw
n bo
th u
pstr
eam
and
dow
nstr
eam
of t
he ri
ver r
elat
ive
to th
e da
m. A
ll sa
lmon
idss
paw
n fa
r ups
trea
m a
nd d
owns
trea
m fr
om th
e M
arm
ot d
am. H
owev
er, t
he C
hino
ok sa
lmon
hav
e se
cond
ary
spaw
ning
are
as ju
st a
bove
the
Mar
mot
dam
, thu
s the
se sp
ecie
s may
be th
e m
ost a
ffect
ed a
s a re
sult
of th
e se
dim
ent t
rans
port
in th
e re
serv
oir.
Gra
in S
ize
Dis
trib
utio
n
0102030405060708090100 0.
010.
11
1010
010
0010
000
diam
eter
(mm
)
% finer
A B1 B2 OB
Tota
l
Res
ults
Follo
win
g 3
wee
ks o
f fie
ld o
bser
vatio
ns a
nd st
udy
at th
e Sa
ndy
Riv
er, O
rego
n, th
e na
ture
and
su
itabi
lity
of sa
lmon
spaw
ning
hab
itat w
as e
valu
ated
and
map
ped
acro
ss se
vera
l rea
ches
do
wns
trea
m o
f Mar
mot
Dam
. The
opt
imal
gra
in si
ze d
iam
eter
for s
alm
on sp
awni
ng e
ffort
s in
the
Sand
y R
iver
was
det
erm
ined
to ra
nge
betw
een
the
diam
eter
s of2
0mm
and
47m
m. T
he
idea
l are
as fo
r spa
wni
ng h
abita
t was
bas
ed o
n ex
istin
g fis
h lit
erat
ure
gath
ered
by
the
fore
st
serv
ices
. The
re w
as c
onsid
erab
le fo
cus o
n sid
e ch
anne
ls an
d ar
eas w
ith m
inim
al h
uman
ac
tivity
and
low
disc
harg
e.
Ack
now
ledg
emen
tsI w
ould
like
to th
ank
Dr.
Pete
r Wilc
ock
and
Chuc
k Po
dola
kat
John
s Hop
kins
U
nive
rsity
. I w
ould
also
like
to th
ank
Kar
en H
ill a
nd Je
ff M
arr f
or th
e th
eir i
nval
uabl
e gu
idan
ce. I
wou
ld li
ke to
than
k th
e N
atio
nal C
ente
r for
Ear
th-S
urfa
ce D
ynam
ics (
NCE
D)
and
St. A
ntho
ny F
alls
Labo
rato
ry (S
AFL
).Disc
ussio
nTh
e M
arm
ot D
am re
mov
al re
sear
ch p
roje
ct w
ill c
ontin
ue in
to n
ext y
ear.
Furt
her r
esea
rch
will
be
cond
ucte
d to
det
erm
ine
chan
ge d
etec
tion
in th
e ri
ver b
edfo
llow
ing
a m
assiv
e lo
ad o
f se
dim
ent t
rans
port
dow
nstr
eam
from
the
dam
. Thi
s map
ping
effo
rt w
as c
ondu
cted
to e
nsur
e a
deep
er u
nder
stan
ding
of t
he b
iolo
gica
l im
pact
of s
trea
m re
stor
atio
n. In
effo
rt to
det
erm
ine
the
optim
al g
rain
size
for s
paw
ning
hab
itat,
the
dow
nstr
eam
reac
h of
the
rive
r was
m
etic
ulou
sly m
appe
d ev
en in
are
as w
ith n
o sp
awni
ng su
itabi
lity.
Thi
s dat
a w
ill p
rovi
de a
ba
sis to
det
ect t
he e
xact
cha
nge
in th
e ge
omor
phol
ogy
of th
e ri
ver a
nd c
an b
e us
ed in
futu
re
dam
con
stru
ctio
n an
d re
mov
al p
roje
cts.
Mar
mot
Dam
bef
ore
rem
oval
.Th
e Sa
ndy
Riv
er a
t Oxb
ow P
ark,
just
one
hou
r eas
t of P
ortla
nd.
Coho
Sal
mon
Red
dsem
bedd
ed in
gra
vel.
Faci
esM
aps a
t Oxb
ow P
ark
whe
re si
gnifi
cant
spaw
ning
act
ivity
occ
urs i
n th
e fa
ll.
Pebb
le C
ount
ing
alon
g th
e ri
verb
ank.
Back
grou
ndTh
e co
nstr
uctio
n of
the
Mar
mot
Dam
forc
es se
vera
l disa
dvan
tage
s to
the
salm
onid
popu
latio
n of
the
Sand
y R
iver
. Dam
s alte
r the
nat
ural
m
igra
tion
pass
ages
in th
e up
stre
am d
irec
tion.
Dam
s neg
ativ
ely
mod
ify u
pstr
eam
and
dow
nstr
eam
aqu
atic
env
iron
men
ts, i
nclu
ding
: th
erm
al st
ratif
icat
ion
of th
e re
serv
oir;
dow
nstr
eam
flow
alte
ratio
n an
d te
rmin
atio
n of
inun
datio
n of
dow
nstr
eam
floo
dpla
ins;
sedi
men
t an
d nu
trie
nt tr
appi
ng in
rese
rvoi
rs.
