North Park Lake Aquatic Ecosystem Restoration · View of the North Fork Pine Creek arm of the lake...
13
North Park Lake Aquatic Ecosystem Restoration Project Steven Smallhoover, P.E. Douglas Aiken, P.E. Allegheny County Department of Public Works North Park Lake Aquatic Ecosystem Restoration North Park Lake Aquatic Ecosystem Restoration Project Pine Creek Dam Completed in 1936 Earthen Embankment Dam with an impervious concrete cutoff wall core – 1,130 ft long, 33 ft high Water sources – Pine Creek, North Fork Pine Creek, Irwin Run Fixed Crest overflow EL 960. • Historic Photo – View of the North Fork Pine Creek arm of the lake looking downstream. The boathouse is in the center of the photo. North Park Lake Aquatic Ecosystem Restoration Project • When initially constructed lake was 75 acres in size and approximately 24 feet deep near the face of the dam. – Pine Creek Watershed • Drainage area of Pine Creek -67.5 square miles • Pine Creek upstream of North Park Dam – 14.2 square miles with channel slope of 34 feet per mile • North Fork Pine Creek – 10 square miles with channel slope of 35 feet per mile Map courtesy of Pine Creek Watershed Coalition North Park Lake Problem Statement • Uncontrolled surface runoff carrying sediment to the lake from development had resulted in a permanent loss of 12 acres of open water • The 12 acres lost occurred in the Pine Creek arm – receives the highest inflow and the highest suspended sediment • Lake not only reduced in size, but also had a severely degraded remaining aquatic habitat. • Due to enrichment from excessive runoff, the lake had become eutrophic and filled with an overgrowth of algae • Pennsylvania Fish and Boat Commission 1997 and 2002 – Reports classified North Park Lake as a shallow, eutrophic, turbid lake that suffers from a siltation problem.
Transcript of North Park Lake Aquatic Ecosystem Restoration · View of the North Fork Pine Creek arm of the lake...
Nort
h P
ark
Lake A
quati
c
Ecosyste
m R
esto
rati
on
Pro
ject
Ste
ven
Sm
allh
oover,
P.E
. D
ou
gla
s A
iken
, P.E
. A
llegh
en
y C
ou
nty
Depart
men
t of Pu
blic W
ork
s
Nort
h P
ark
Lake A
quati
c E
cosyste
m R
esto
rati
on
Nort
h P
ark
Lake
Aquati
c E
cosyste
m
Resto
rati
on P
roje
ct
Pin
e C
reek D
am
C
om
ple
ted in
1936
Eart
hen
Em
ban
km
en
t D
am
w
ith
an
im
perv
iou
s c
on
cre
te
cu
toff
wall c
ore
– 1
,130 f
t lo
ng,
33 ft
hig
h
Wate
r sou
rces –
Pin
e C
reek,
Nort
h F
ork
Pin
e C
reek, Ir
win
R
un
Fix
ed C
rest
overf
low
EL 9
60.
•H
isto
ric P
hoto
– V
iew
of
the N
ort
h F
ork
Pin
e C
reek a
rm o
f th
e lake lookin
g d
ow
nstr
eam
. Th
e b
oath
ou
se is in
th
e
cen
ter
of
the p
hoto
.
Nort
h P
ark
Lake
Aquati
c E
cosyste
m
Resto
rati
on P
roje
ct
•W
hen
in
itia
lly c
on
str
ucte
d
lake w
as 7
5 a
cre
s in
siz
e
an
d a
ppro
xim
ate
ly 2
4 f
eet
deep n
ear
the face o
f th
e
dam
.
Hi st ori cPh ot o –Vi ewofth ePi neC reek armofth el ak el ooki ngd ownst reamt owardth ed am
Pin
e C
reek W
ate
rsh
ed
•D
rain
age a
rea o
f Pin
e C
reek -
67.5
squ
are
miles
•Pin
e C
reek
upstr
eam
of
Nort
h
Park
Dam
– 1
4.2
squ
are
miles w
ith
ch
an
nel slo
pe o
f 34 feet
per
mile
•
Nort
h F
ork
Pin
e
Cre
ek –
10 s
qu
are
m
iles w
ith
ch
an
nel slo
pe o
f 35 feet
per
mile
Map c
ou
rtesy o
f Pin
e C
reek W
ate
rsh
ed C
oaliti
on
Nort
h P
ark
Lake
Pro
ble
m S
tate
men
t •
Un
con
trolled s
urf
ace r
un
off
carr
yin
g s
edim
en
t to
th
e
lake fro
m d
evelo
pm
en
t h
ad r
esu
lted in
a p
erm
an
en
t lo
ss o
f 12 a
cre
s o
f open
wate
r
•Th
e 1
2 a
cre
s lost
occu
rred in
th
e P
ine C
reek a
rm –
re
ceiv
es t
he h
igh
est
inflow
an
d t
he h
igh
est
su
spen
ded
sedim
en
t
•Lake n
ot
on
ly r
edu
ced in
siz
e, bu
t als
o h
ad a
severe
ly
degra
ded r
em
ain
ing a
qu
ati
c h
abit
at.
•D
ue t
o e
nri
ch
men
t fr
om
excessiv
e r
un
off
, th
e lake h
ad
becom
e e
utr
oph
ic a
nd fille
d w
ith
an
overg
row
th o
f alg
ae
•Pen
nsylv
an
ia F
ish
an
d B
oat
Com
mis
sio
n 1
997 a
nd
2002 –
Report
s c
lassifie
d N
ort
h P
ark
Lake a
s a
sh
allow
, eu
troph
ic, tu
rbid
lake t
hat
su
ffers
fro
m a
silta
tion
pro
ble
m.
Nort
h P
ark
Lake –
Nort
h F
ork
Pin
e C
reek
Nort
h P
ark
Lake –
Nort
h F
ork
Pin
e C
reek
Nort
h P
ark
Lake –
Gate
Hou
se A
rea a
nd D
am
Pro
ject
Au
thori
ty
•Federa
l A
uth
ori
ty –
Secti
on
206 A
qu
ati
c
Ecosyste
m R
esto
rati
on
•Federa
l S
pen
din
g L
imit
-$5,0
00,0
00
•Pro
jects
are
cost
sh
are
d w
ith
local spon
sors
. 65%
Fed /
35%
local
•LO
CA
L S
PO
NS
OR
– A
llegh
en
y C
ou
nty
-
$2,7
00,0
00
•R
em
ain
der
of
work
wou
ld b
e A
llegh
en
y C
ou
nty
re
spon
sib
ilit
y
•Tota
l Pro
ject
Cost
Lim
it -
$20,0
00,0
00
Pla
nn
ing P
rocess
•Pro
ject
Init
iati
on
-1999
•S
tep 1
– R
econ
nais
san
ce L
evel Pre
lim
inary
R
esto
rati
on
Pla
n P
urp
ose –
To d
ete
rmin
e if
there
is a
pro
ject,
if
there
is F
edera
l In
tere
st,
an
d d
evelo
p a
pre
lim
inary
solu
tion
Pla
nn
ing P
rocess P
relim
inary
R
esto
rati
on
Pla
n
•U
SA
CE
2002 L
ake A
naly
sis
•Lake is a
warm
, sh
allow
, m
inera
lize
d, n
utr
ien
t ri
ch
, eu
troph
ic im
pou
ndm
en
t
•D
issolv
ed O
xygen
tota
lly d
eple
ted a
t th
e b
ott
om
of
the lake
•A
lso s
olu
ble
meta
ls a
nd a
mm
on
ia a
nd h
ydro
gen
su
lfid
e h
as a
ccu
mu
late
d.
•D
istr
ict
con
sid
ere
d p
reserv
ing v
ers
us r
esto
rin
g t
he
open
wate
r aqu
ati
c h
abit
at
at
Nort
h P
ark
Lake
•Fir
st
alt
ern
ati
ves d
evelo
ped w
ere
mean
t to
redu
ce
on
goin
g s
edim
en
tati
on
an
d p
reserv
e w
hat
open
w
ate
r re
main
ed w
ith
in t
he lake.
n
Pla
nn
ing P
rocess P
relim
inary
R
esto
rati
on
Pla
n
•A
ltern
ati
ve 1
-U
pstr
eam
Sedim
en
tati
on
B
asin
s w
ith
in t
he p
ark
Larg
e S
edim
en
t Loads a
nd f
ine s
edim
en
t w
ou
ld m
ake t
he
siz
e o
f basin
s r
equ
ired u
npra
cti
cal
•A
ltern
ati
ve 2
-In
Lake S
edim
en
t B
asin
s
Inclu
din
g M
ars
hall L
ake
Pla
nn
ing P
rocess P
relim
inary
R
esto
rati
on
Pla
n
•Pro
posed c
on
str
ucti
ng a
poro
us r
ock d
ike
acro
ss t
he P
ine C
reek a
rm o
f th
e lake.
•S
ecti
on
of
the lake u
pstr
eam
of
the d
ike
wou
ld h
ave b
een
sacri
ficed t
o a
ct
as a
sedim
en
tati
on
basin
•R
ecom
men
ded in
sta
llin
g n
ew
valv
e t
o a
llow
th
e d
rain
ing o
f M
ars
hall L
ake
Pla
nn
ing P
rocess P
relim
inary
R
esto
rati
on
Pla
n
Poro
us R
ock D
ike (w
etl
an
d p
rote
cti
on
barr
ier)
Pla
nn
ing P
rocess
Post
Pre
lim
inary
Resto
rati
on
Pla
n D
ata
•S
edim
en
t Load –
5,2
00 t
on
s o
f sedim
en
t lo
ad in
to lake p
er
year.
95%
deposit
ed
•O
rigin
al sto
rage c
apacit
y o
f la
ke w
as 5
68
acre
-feet
dow
n t
o 2
97 a
cre
-feet
from
2001 d
ata
•Loss o
f 48%
of
capacit
y f
rom
1936-2
001
•S
edim
en
t re
moval w
ou
ld b
e r
equ
ired
Pla
nn
ing P
rocess F
easib
ilit
y P
hase –
D
eta
iled P
roje
ct
Report
Feasib
ilit
y P
hase -
Com
men
ced in
2003
Pu
rpose –
To e
valu
ate
alt
ern
ati
ves a
nd
dete
rmin
e t
he b
est
alt
ern
ati
ve
for
the p
roje
ct
wit
hin
th
e
fun
din
g c
on
str
ain
ts
Pla
nn
ing P
rocess
Deta
iled P
roje
ct
Report
•D
ete
rmin
e q
uan
tity
of
sedim
en
t to
be
rem
oved
•C
hara
cte
rize
th
e s
edim
en
t to
be r
em
oved
•Perf
orm
Cu
ltu
ral R
esou
rces a
nd H
TR
W
Stu
die
s
•D
ete
rmin
e r
eal esta
te r
equ
irem
en
ts
•D
ete
rmin
e B
est
alt
ern
ati
ve f
or
Sedim
en
t R
em
oval
Pla
nn
ing P
rocess
Deta
iled P
roje
ct
Report
•Id
en
tify
Dis
posal A
rea
•Layou
t ou
t aqu
ati
c h
abit
at
en
han
cem
en
t
•Featu
res:
1.
Dete
rmin
e a
qu
ati
c h
abit
at
ben
efits
2.
Develo
p t
ota
l pro
ject
cost
esti
mate
3.
Develo
p p
roje
ct
sch
edu
le
•D
ete
rmin
e p
erm
its r
equ
ired t
o m
ove
forw
ard
Pla
nn
ing P
rocess
Sedim
en
t C
hara
cte
riza
tion
•Pin
e C
reek A
rm g
reen
ish
gra
y,
silty
cla
ys
wit
h o
rgan
ics E
xte
nded d
epth
s o
f gre
ate
r th
an
10ft
. B
en
eath
was a
very
loose s
ilty
san
d h
igh
mois
ture
con
ten
t
•N
ort
h F
ork
Pin
e C
reek A
rm t
wo f
oot
or
less
of very
soft
sedim
en
t befo
re d
en
ser
sedim
en
t an
d s
oils
Pla
nn
ing P
rocess D
eta
iled P
roje
ct
Report
– A
ltern
ati
ve A
naly
sis
•Q
uan
tity
of
Rem
oval 315,0
00 c
ubic
yard
s
Alt
ern
ati
ves
1.
Do n
oth
ing A
ltern
ati
ves r
evie
wed f
or
cost
an
d t
ime
2.
Don
’t D
rain
th
e L
ake -
Hydra
ulic
Dre
dgin
g
3.
Dra
in t
he L
ake –
Mech
an
ical
Excavati
on
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•D
o N
oth
ing (w
ith
ou
t pro
ject
alt
ern
ati
ve) silt
an
d s
edim
en
t w
ill
cau
se lake t
o b
ecom
e in
cre
asin
gly
sh
allow
resu
ltin
g in
in
cre
ased w
ate
r te
mpera
ture
s, decre
ased d
issolv
ed
oxygen
level, in
cre
ased n
utr
ien
t en
rich
men
t. N
ort
h P
ark
Lake w
ou
ld
even
tually fill in
an
d e
nti
re lake w
ill
revert
to w
etl
an
ds
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•Lake r
evert
s t
o w
etl
an
ds
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•Lake D
rain
ing -
Com
ple
tely
dra
in t
he
lake, allow
sedim
en
t to
dry
su
ffic
ien
tly
to a
llow
lan
d-b
ased e
qu
ipm
en
t to
en
ter
the lakebed a
nd e
xcavate
accu
mu
late
d s
edim
en
t w
ou
ld r
equ
ire
str
eam
div
ers
ion
s t
o c
on
tain
th
e t
hre
e
trib
uta
ries a
s t
hey flo
w t
hro
ugh
th
e
dra
ined lake b
ed
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•Lake d
rain
ed w
ith
str
eam
div
ers
ion
ch
an
nel
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•Lake d
rain
ing w
ith
lan
d b
ased e
qu
ipm
en
t an
d e
xcavati
on
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•Lake d
rain
ing w
ith
lan
d b
ased e
qu
ipm
en
t an
d e
xcavati
on
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•H
ydra
ulic D
redgin
g –
No L
ake D
rain
ing
Uti
lize
flo
ati
ng h
ydra
ulic d
redgin
g
equ
ipm
en
t to
rem
ove t
he s
edim
en
t.
Sedim
en
t slu
rry p
um
ped t
o d
ew
ate
rin
g
are
as.
Wou
ld h
ave t
o u
se G
eotu
bes t
o d
ry
mate
rial du
e t
o lack o
f space f
or
larg
e
dry
ing a
reas.
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•H
ydra
ulic D
redgin
g –
Dre
dge e
qu
ipm
en
t
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•H
ydra
ulic D
redgin
g -
Geotu
bes
Pla
nn
ing P
rocess A
ltern
ati
ve A
naly
sis
•G
eotu
bes –
Han
gin
g B
ag T
est
1.
Com
bin
ed s
edim
en
t slu
rry s
am
ple
wit
h
non
-toxic
poly
mer
added
2.
Geotu
bes w
ith
poly
mer
will dry
mate
rial
3.
Need low
gra
de laydow
n a
reas f
or
geotu
bes t
o b
e e
ffecti
ve
Pla
nn
ing P
rocess D
eta
iled P
roje
ct
Report
– A
ltern
ati
ve A
naly
sis
•R
ecom
men
ded A
ltern
ati
ve –
Dra
in t
he L
ake
– M
ech
an
ical E
xcavati
on
•C
om
pari
son
Dra
in t
he L
ake -
$28 /
cu
bic
yard
rem
oved
•12 m
on
th c
on
str
ucti
on
du
rati
on
Hydra
ulic
Dre
dgin
g -
$35 /
cu
bic
yard
rem
oved
•24 m
on
th c
on
str
ucti
on
du
rati
on
Pla
nn
ing P
rocess
Deta
iled P
roje
ct
Report
– D
isposal A
rea
•W
ildw
ood M
ine D
isposal S
ite
1.
65 A
cre
s S
ite
2.
1.5
miles f
rom
Pin
e C
reek D
am
3.
Recla
imed c
oal w
aste
pile t
hat
was
covere
d w
ith
fly
ash
, h
eavily f
ert
iliz
ed
an
d p
lan
ted w
ith
gra
ss t
o h
elp
pre
ven
t ero
sio
n
Pla
nn
ing P
rocess
Wildw
ood D
isposal A
rea
Nort
h P
ark
Lake
Wildw
ood
Dis
posal
Are
a
Pla
nn
ing P
rocess
Wildw
ood D
isposal A
rea
Pla
nn
ing P
rocess
Wildw
ood D
isposal A
rea
Pla
nn
ing P
rocess
En
vir
on
men
tal Featu
res
•W
etl
an
d P
rote
cti
on
Barr
ier
•C
oir
Logs a
nd S
hore
lin
e P
lan
tin
gs
•Fis
h H
abit
at
Str
uctu
res
• O
spre
y N
ests
Pla
nn
ing P
rocess
En
vir
on
men
tal Featu
res
•W
etl
an
d P
rote
cti
on
Barr
ier
Pla
nn
ing P
rocess
En
vir
on
men
tal Featu
res
•C
oir
Logs a
nd S
hore
lin
e P
lan
tin
gs
Pla
nn
ing P
rocess
En
vir
on
men
tal Featu
res
•Fis
h H
abit
at
Str
uctu
res
Pla
nn
ing P
rocess
En
vir
on
men
tal Featu
res
•O
spre
y N
est
Con
str
ucti
on
Ph
ase
•Th
ree C
on
tracts
1A
. S
ite P
repara
tion
Con
tract
– A
llis
on
Park
C
on
tracto
rs I
nc. (A
llegh
en
y C
ou
nty
Con
tract)
1B
. Ir
win
Ru
n P
on
d S
upple
men
tal C
on
tract
- A
llis
on
Park
Con
tracto
rs I
nc. (A
llegh
en
y
Cou
nty
Con
tract)
2.
Ph
ase I
Sedim
en
tati
on
Rem
oval – C
J M
erl
o –
(F
edera
l C
on
tract
3.
Ph
ase I
I S
edim
en
tati
on
Rem
oval – C
J M
erl
o –
(A
llegh
en
y C
ou
nty
Con
tract)
Con
str
ucti
on
Ph
ase T
imelin
e
•S
epte
mber
2009 –
Lake D
rain
ed
•O
cto
ber
2009 –
Fis
h R
escu
e
•Jan
uary
2010 –
Wildw
ood D
isposal S
ite P
rep
Work
•A
pri
l 2010 – L
ake R
e-d
rain
ed
•M
ay 2
010 – S
tream
Div
ers
ion
In
sta
llati
on
•Ju
ne 3
0, 2010
– S
edim
en
t R
em
oval
Com
men
ces
•Ju
ne 1
0, 2011 –
Re-O
pen
ing C
ere
mon
y
•Ju
ly 8
, 2011 –
Wate
r cre
sts
over
the d
am
Con
str
ucti
on
Ph
ase
•D
rain
ing t
he lake (th
e f
irst
tim
e)
Con
str
ucti
on
Ph
ase
•R
ose B
arn
Access R
am
p
Con
str
ucti
on
Ph
ase
•Tem
pora
ry R
oad C
on
str
ucti
on
Con
str
ucti
on
Ph
ase
•Pearc
e M
ill R
oad A
ccess R
oad C
on
str
ucti
on
Con
str
ucti
on
Ph
ase
•S
tream
Div
ers
ion
Ch
an
nel E
xcavati
on
Con
str
ucti
on
Ph
ase
•S
tream
Div
ers
ion
Ch
an
nel Lin
er
insta
llati
on
Con
str
ucti
on
Ph
ase
•N
ort
h F
ork
Pin
e C
reek S
tream
Div
ers
ion
Con
str
ucti
on
Ph
ase
•S
edim
en
t R
em
oval
Con
str
ucti
on
Ph
ase
•S
edim
en
t R
em
oval
Con
str
ucti
on
Ph
ase
•Tem
pora
ry H
au
l R
oad in
Lakebed
Con
str
ucti
on
Ph
ase
•Tru
ck W
ash
Con
str
ucti
on
Ph
ase
•A
eri
al Ph
oto
Con
str
ucti
on
Ph
ase
•Ph
ase 1
Sedim
en
t R
em
oval C
om
ple
tion
C
on
str
ucti
on
Ph
ase
•W
ildw
ood D
isposal A
rea
Con
str
ucti
on
Ph
ase
•Ph
ase 2
in
Pro
gre
ss
Con
str
ucti
on
Ph
ase
•A
llegh
en
y C
ou
nty
’s P
hase 2
work
moves o
n
in t
he w
inte
r
Con
str
ucti
on
Ph
ase
•A
llegh
en
y C
ou
nty
’s P
hase 2
work
moves o
n
in t
he w
inte
r Tre
e s
tum
p f
rom
th
e o
rigin
al la
ke
bed u
ncovere
d
un
der
8 f
eet
of
silt
Con
str
ucti
on
Ph
ase
•Ph
ase 2
in
Pro
gre
ss M
arc
h 3
0,
2011 S
edim
en
t Level
Norm
al W
ate
r Lin
e
Con
str
ucti
on
Ph
ase
•Ph
ase 2
in
Pro
gre
ss M
arc
h 3
0,
2011 N
orm
al W
ate
r Lin
e
Sedim
en
t Level
Con
str
ucti
on
Ph
ase
Fis
h s
tru
ctu
res:
•Post
Clu
ste
rs
•R
ocks S
tars
•S
pid
er
Hu
mps
•S
tum
p C
luste
rs
Dia
gra
ms c
ou
rtesy o
f Pen
nsylv
an
ia F
ish
an
d
Boat
Com
mis
sio
n
Con
str
ucti
on
Ph
ase
•Fis
h s
tru
ctu
res in
pla
ce (w
ait
ing f
or
the
lake t
o f
ill)
Fis
h H
abit
ats
•R
ock S
tars
•S
pid
er
Hu
mps
•Post
Clu
ste
rs
•S
tum
p C
luste
rs
•R
ock H
um
ps
Con
str
ucti
on
Ph
ase
•In
Au
gu
st
2010 t
he A
llegh
en
y C
ou
nty
Depart
men
t of
Pu
blic W
ork
s
begin
s t
he p
rocess t
o a
men
d t
he E
nvir
on
men
tal A
ssessm
en
t an
d
Perm
its t
o in
clu
de s
edim
en
t re
moval in
Irw
in R
un
Pon
d a
nd d
isposal
of sedim
en
t in
th
e B
abcock C
on
tain
men
t A
rea.
Con
str
ucti
on
Ph
ase
•B
abcock C
on
tain
men
t A
rea
Perm
itte
d a
nd
con
str
ucte
d in
1981
as a
dry
ing b
ed for
sedim
en
t re
moval
Sit
e h
as s
ubsu
rface
dra
inage s
yste
m
Filte
red w
ate
r dra
ins
into
sw
ale
an
d P
ine
Cre
ek
Available
volu
me f
or
sedim
en
t dis
posal
-35,0
00 c
ubic
yard
s
Con
str
ucti
on
Ph
ase
•B
abcock C
on
tain
men
t S
ite
Con
str
ucti
on
Ph
ase
•Ir
win
Ru
n P
on
d D
ivers
ion
Ch
an
nel C
on
str
ucti
on
Con
str
ucti
on
Ph
ase
•Ir
win
Ru
n P
on
d S
edim
en
t R
em
oval
Com
ple
tion
Con
str
ucti
on
Ph
ase
•Ir
win
Ru
n P
on
d F
illin
g I
n
Boat
Lau
nch
R
am
p
Con
str
ucti
on
Ph
ase
•Ir
win
Ru
n P
on
d B
oat
Lau
nch
Concre
te R
evetm
ent
Mat
•E
lim
inate
s e
rosio
n o
f soils
into
pon
d
•N
egati
ve s
torm
wate
r ru
noff.
•C
an
han
dle
heavy v
eh
icle
lo
ads
•M
at
acts
a p
erm
eable
pavem
en
t an
d a
llow
s w
ate
r to
in
filt
rate
in
to g
rou
nd
•M
inim
al m
ain
ten
an
ce
Con
str
ucti
on
Ph
ase
Wildw
ood D
isposal A
rea -
Ready f
or
seedin
g
Nort
h P
ark
Lake
Aqu
ati
c E
cosyste
m R
esto
rati
on
•W
ate
r cre
sts
over
the d
am
Ju
ly 8
, 2011
Nort
h P
ark
Lake
Aqu
ati
c E
cosyste
m R
esto
rati
on
Qu
esti
on
s?
