United States Committee on Large Dams. U.S. Dams
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18
KINZUA DAM
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PLAN
STANDARD
SEA
LEVEL DATUM
1929
GENERAL
ADJUSTMENT
I
0utlert
0perating
illachinery
Iop
ol
Gato
El. 1365.0
(El.4l6,l,m)
Sluice
Gate
0perating
Chatnber
Bridee
tl. 1375.0
(El.4l9,lm)
Fixed
Crest Et.134i.0
(El.
408,7m)
Axis
of Dam
Trash Rack
lnvert
El.1205.0
(El.
367.3m)
e.
Er.1375.0
(El.
1l9,lm)_lJ_-
ffi,,
Fu'Et.
t365.0
Sand
& Gravel Drain
lmpervious
Blanket
L--------= ON
I
-ut
---i3-t
Cut-0ff
Inta
ke
RoadwaY
Axis of
Da
illins Wei
Parking
!l
o)
:.
5
s
wl
llr
:
Crest Gate
(El
4l6,lm)
TYPICAL
EMBANKMENT SECTION
S,PITTWAY
SECTION
KINZUA
DAM
Aerial
view
of
Kinzua
Dam
and
Allegheny
Reservoir.
19
E
Georse
Cingle,
Jr.,
Section
Chief,
Project
Planning
Branch
Fitt.B"teh
bidtrict,
United
States.Army
Corps
of
Engineers
Kinzua
Dam
and
Allegheny
Reservoir
are
situ-
ated
in
northwestern
Pennsylvania
and
south-
western
New
York,
approximately
200 miles
by
river
(320
km),
above
the
mouth
of
the
Allegheny
River
at
Pittsburgh,
Pennsylvania.
The
project is
operated
jointly
for
flood
control
and
low
flow
aug-
mentation
as
a
unit
of
the
coordinated
reservoir
system
for
flood
control
and
water
resource
de-
velopment
in the
Allegheny
and
Ohio
River
Valleys'
In addition,
the
project
provides
extensive
recre-
ational
opportunities
and
will
serve
as
the
lower
reservoir
for
a
privately
developed
pumped
storage
installation
currently
under
construction.
The
dam
is
a
1,897-ft
(5?8-m)
combined
earth
and
concrete
gravity
structure,
1?9
ft
(55
m)
in
height
above
stream
bed,
with
a
gated
spillway.
It controls
a
drainage
area
of
2,180
sq
mi
(5.646
x
10u m2)
and
will
p'rovide 1,180,000
ac-ft
(1.456
x
106
m')
of
gross
storage.
Immediately
downstream
of
the
dam
will
be
a
private
powerstation containing
two
reversible
pumpturbines and
one
non-reversible
turbine
with
a
total
combined
average
generating
capacity
of
380,000
kw.
The
powerstation will
be
connected
to
the
Allegheny
Reservoir
and
a second,
upper
reservoir
located
on
a
mountain
above
the
dam.
T'he
pumped
storage
facility
is being
devel-
oped
as
a
joint
venture
by the
Cleveland
Electric
Illuminating
Company
and
'l;he
Pennsylvania
Elec-
tric
Company
unde:c
license
from
the
Federal
Power
Commission.
Operation
of
1;he
installation
will
be
coordinated
with
r,eleases
llrom
Kinzua
Dam to
in-
sure
adherence
to the
estab'lished
flow
sehedules
for
the
Allesheny
River.
Allegheny
Reservoir
is
tlhe seventh
reservoir
tcr
be
placed
in operation
in
the
Allegheng
River
Basin
and
the
ninth
such
project
in the
watershed
area,
above
Pittsburgh,
PennsYlvaunia.
Studies
for
ther
selection,
of the
dam
site
wers)
initiated
in
1936
and
conlbi:nued
intermittently'
a$i
funds
were
made
available,
until
1967.
These
in'
vestigations
conclu,ded
that
the
present
site
with
a
combination
dam
of
a
gated'
concrete
ogee
spillway
joined
to a
rolled
'earth
enrbankment
was
the
mosl"
economical
of
the
several
prlans
investigated.
In
1962,
when
reonstruction of the
left abutmenjb
concrete
section
and
portions
of
the
right
abutment
embankment
was
underwety''
a
portion
of the
cut-
off
lying
nearly
perpendicular to
the
dam
was
con-
structed
in the
wet.
The
riverward
section
of
thr:
impervious
blankel[
coverinrg
this
portion
of
the
cut-
off
and
a
part
of
the
upstream
random
embankmenb
was then
construc'bed.
In
1963,
the
second
stetge
cofferdam
inclosin$J
the
right
bank
co:nstruction,
area
was
installed
and
the
excavation
for
the
riglhl;
abutment
concrete
sec-
tion
and
embanknrent
foundation
initiated.
During
this
stage
of
conrstruction
and
while
the
embank-
20
KINZUA
DAM
Stream flow
Drainage area
above dam:
sq
mi
(m2
x
106)
----------
Average
unregulated flow
at
dam:
cfs
(m3/sec)
Minimum daily
cfs
(m3lsec)
SUMMARY
OF
PRINCIPAL
FEATURES
Location
In northwesteln
Pennsylvania,
about
200
miles
by
river
(320
km)
above tha mouth of
the
Allegheny
River
at
Pittsburgh
Purpose
Flood
control,
low flow
augmentation
(which
ineludes
water
quality
control)
and
recreation.
Also
serves
as
the lower
reservoir
for a
privately
developed
pumped
storage
project
Owner
and
operator
United States Government
Engineering
and
construction
supervislon
Pittsburgh
District, U. S.
Army
Corps
of
Engineers,
Pittsburgh,
Pennsylvania; Buffalo District,
U. S.
Army
Corps
of Engineers,
Buffalo,
New
York
Chronology
Construction
started:
February 1960
Reservoir
filling
started:
December 1966
Project cost
(estimated)
$106,600,000
Private
pumped
storage installati,on
The
Seneca
Pumping
and Gerrerating
Plant associated
with
the
Kinzua Dam is
joi:ntly
o\rrned
by the Cleve-
land Electric
Illuminating Co.
end
the Pennsylvania
Electric
Co.
Engi:neering and Construction Supervision
are
by
Harza Engineering Co.
Chronology:
Construction
starl;ed: Apri,t
1966
Scheduled complelbion: May
1969
Capacity:
380,000
kw
Major
elements:
Lower
intake structure
upst:ream of Kinzua Dam
Two 15-ft
(4,6-m)
diam
steel low head conduits from
the
lower
intake struel;ure
through Kinzua Dam,
to the
power
sitation
Power station
with
two
reversible fixed-blade
pump-
turbines each
rated at
alcout
175,000
kw, and one
high
head conventional Francis type
turbine of
about
30,000 kw
Steel and concret,e
lined
tunnel,
22 ft
(6,7
m) diam,
extending into the mount;ain
0.5
mile
(0,8
km)
Upper reservoir zrbout
800
ft
(244
m)
above river
Lower reservoir: Al)legheny R;eservoir
Upper reservoir:
Storage capacity:
ac-ft
(m3
x 106)
--
6,200
(7,65)
Area
at full
pool,,
elevation
2,072
ft
(631,5
m):
acres
(m2
x
10,4) - -------
106
(43)
Turbine operation:
One
reversible unit discharges only into the lower
reservoir
One reversible
urnit,
with
a divided
draft
tube,
dis-
charges either
into
the
lower
reservoir
or
down
river
Non-reversible
unit disehar:ges
only
down river
Cost
(estimated):
$40,000,000
ment
foundation
area was bejing
excavated,
as con-
templated
in
the design, the exposed
materials
were
inspected,
sampled,
and tested for
gradation
to more
accurately
determine the
necessity
for revising
the
dam design to
provide
for
additional
control
of
un-
derground water fllow through
the embankment
foundation.
The
contract
pla,ns
incorporated
stan-
dard methods
of design
to
insure
against
uplift
and/or
piping;
however,
4uliing design it
was
de-
cided
to
postpone
a,ny
furth,er decisions
until
the
embankment foundation couldl
be further
evaluated
when
exposed
to view.
Inspection and
grradation
t,ests of the
foundation
materials indicated the
need for further
detailed
soils and
hydro-geological
inLvestigations
because of
a
potential piping
condition.
The results
of these
investigations indicarted the alluvial foundation ma-
terials to be of
a
hielh
or,der
of
permeability
and the
possibility
of
piping
to
be so
eireat
that steps
,should
be
taken to
prevent
a
migral;ion
of
fines
and critical
gradients
in
the vicinity of the downstream
toe of
the dam.
After
considerable
examination
and study
of the
preventive
methods
available,,
their application un-
der
project
conditions,
effect;iveness
and cost,
it was
concluded that
an undergrrcund
concrete
wa]l,
as
constructed
by the
slurry trench method, would be
the
most
practicable.
Icancla,, Ltd.,
submitted
the
final
Iow
bid
for
the
propos'ed
wall for
the
ICOS
method
of
construction.
Ars
developed by
Icanda,
the
concrete wall is
generally'
established
in L2-
to
20-ft
(3,7-
to
6-m)
][ong
pan.els
by a
progression
of
the following steps:
unregulated flow
at
2,180
(5.646)
3,712
(105)
dam:
L4e
(4)
of
dam:
500
6o,5oo
144,000
(1.456)
(29,6)
to roadway
(71,6)
(59,4)
(320)
maximum
m):
Minimum daily
flow after
completion
cfs
(nr3/sec)
Maximum known
flood
at dam:
cfs
(m3/sec)
(14)
(
1.713
)
(4.0?8)
Maximum
probable
cfs
(m3/sec)
Reservoir
flood
regulated:
Volume
at top
of
spillway
Tairrter
gates,
elevation
1,365
ft
(416,1
m):
ac-ft
(mr
x 106)
1,180,000
Minimum
pool,
elevation
1,240 ft
(378
m):
24,000
ft
(41.6,1
m):
21,180
(8.5?0)
Area of maximum
summer
pool,
elevation
1,328 ft
(40-1,6
m):
acres
(m2
x
10a) 12,080
(4.890)
Length
at full
pool:
miles
(km)
32
(51,5)
f)am
Material
and type: Concrete
gravity
spillway
section
flanked
by
earth
embankment
on right
bank, with
a
concrete
and impervious
fill
cutoff
wall
to bedrock
through
upstream
impervious
blanket
Foundation:
Concrete
section: Interbedded shale
and
siltstone
Embankment section:
Largely alluvial
material in
a
buriecl
valley
in the foundation
rock
Diniensions-fi
(m):
Maximum
height
above
lowest
foundation
over dam 296
Illaximum base
widths
(approximate)
:
Concrete section
195
Earth embankment
--------.----
1,050
Outlet
facilities:
Spilhvay
capacity
with
water
surface
at
reservoir level, elevation
1,3?0 ft
(417,6
cfs
(m3lsec)
114,000
(3.228\
Sluice
capacity with water
surface at maximum
reservoir
Ievel, elevation 1,370 ft
(41?,6
m):
cfs
(m3/sec)
300,000
(850)
Spilhvay
controlled
by four' 24-ft
(7,3-m)
high
by
45-ft
(13,i-m)
wide
Tainter
gates
operated by fixed
hoists
Six
low
level
sluices
through
spillway section, each
con-
tlolled
by
two
(service
nnd
emergency) 5.6?-rt
(1,73-m)
by 10.0-ft
(3,05-rn)
slide
gates,
invert elevation 1,205
ft
(367,3
m)
Two
high levcl sluices, one
discharging through
each spray
wall
and each
controllerl
by a 5.67-ft
(1,73-m)
by
10.0-ft
(3,05-m)
slide
gate,
invert elevation
1,300
ft
(396,2
m)
Sluice inlets_
protected
by
trashracks;
and
sluice
gates
operated
hydraulically
from
within the
dam
Two
19-ft
(5,8-m)
diam
openings
provided
in
spillway
seetion
to
preserve
hydroelectric
potential
of
dam.
Pumped
storage
installation
presently
being
carried
out
by
private
companies.
Major
construction
quantities
(estimated)
cu
yd
m3
1,101,000
942.000
238,000
182.000
2,?65,000
1.732.000
468,000
369.000
ac-ft
(m3
x
106)
Area
at
full
pool,
elevation
acres
(6t
x t0a)
Dam
and spillway:
Common excavation
Roek excavation
Embankment fill
Concrete
KINZUA
DAM
1897.0'
(578,2m)
E
Relocated
Statrs
Route
59
2t
1098.5'
(334,8m)
Roadway
1375.0
(El,4l9,lm)
Vibrrfinl
roivo
Drilliag bif
212 s',
(83,1m)
(62,2
m)
(!18,1m)
f-/
204
0'
3,?2.o',
Penstocks
6-5'8"x10'0"
(1,73m
x 3,05m)
?lE
lorl
lrotE
tttnENT
txcAv^lto
EtClrENr
Orl[tEO
lY CIAI St{Ett
Wl?H
CHlStt
I
utrd
whorr
prc<ticoblr
I
Sluice
0utlets
DOWNSTREAM
IELEVATION
(Stilling
Weir
Not
Shown)
cor?TETED'ANH,
lNrtrcoNNlcllNcCtlnlxlllllNc
ltrNc coNclETEo
olltl,co
wllll
tl?AxolNo
(xltll
rit.
a0f
f.
fro nc h
coNcrtrt
?AXEt
coNcrl?l
?ANIEI,
1.
Establishing
a
guide
trench
and
concrete
guide
walls.
2. Excavation
for the
cutoff
wall
in
panels
or
in
panels
and
speeial
connecting
elernents,
by use of
one or
more of
the
following
items of equipment:
pereussion
drill
rig, clamshell
rig:, combination
of
clamshell
and
percussion
rigs,
special
percusgion
drill
with
guides.
During
the
excavation
by the
above
equip'ment,
the
trench
walls
are
stabilized
by use
of
^
highly
viscous
bentonitic
slurry.
3.
Tremieing
of concrete
into the
trench
panels
and/or
connecting
elements,
displacing
the
stabiliz-
ing
bentonite
slurry
upward
and out
of
the
trench.
The
above
steps
in wall construction
are
shown
schematically.
The completed
wall.is shown on
the
general
plan
upstream
and
approximately
parallel
to
the dam.
latorco,nnrcfitl
lle
nrlall
ESTABLISHING
THE CUT.OFF
WALL
A syste,m
of
well
point
type
lliezometers
was
in-
stalled
through
the
emlbankmer:tt
perpendicular
to
the
dam
axis and
along
the downstream
toe of
the
dam;
and
a
line
of
the
closed
s:ystem,
air-actuated
type
piezometers
was
installed
parrallel
to the
axis
of the
dam
between
the
dam
toe of
slope and
the
concrete
cutoff
wall,
so
as
to
positively
check
the
backwater
and
seepage
conditions
throug:h
the
foun-
dation
and,
also, the
eff:iciency
of
the concrete
cut-
off
wall
itself.
Piezome,tric
datra
compiled to
date
indicates
that
the
wall
is
perfor:ming
its
desired
function.
Final
filling
of
the
reservoir
rrras
initiated
in
De-
cember
1966
and
reach,ed
the
summer
pool
level,
elevation
I,328
ft
(404,6
m), by
IVIay
1967.
The
designs
of
the
structure
are conventional
with
no unusual
features
developed.
Hydraulic
per-
formance
of the
spillwa]',
stillintf
basin, and
sluices
was
verified
by
hydraulie
model
study.
lrnlonilo
lrcr
co(
)o
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votlT
/+\
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rarl
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locr
22
MORROW
POINT
DAM
..,:
W
Aeritl vit'u
luoliing
dorvnstrcanr
irt
321 ft lbovt'
the krn'
point
ol'
the
progress.
Vlrlrrorv I)oitrt Drnr.
foundation. llcmoyal
Thc
highcst
blocks
shorvn
are
of
upstream
r:offerdam
is
in
MORROW
POINT
DAM
23
Floyd
E. Dom,iny,
Commissioner,
Bureau
of Reclamation
United
States
Department of the
Interior,
Washington, D.
C.
Morrow Point Dam
and
Powerplant
are
principal
structures of the Curecanti
Unit
of the Colorado
River
S,torage
Project.
They
are
on the Gunnison
River in west central
Colorado. The
concrete
dam,
constructed for
power generation,
is
the
Bureau
of
Reclamation's highest
double-curvature
thin-arch
dam.
It
is 468 ft
(143
m) high,
LZ ft
(3,7
m)
thick
at the crest, and 52
ft
(15,9
m)
thick at
the base.
The
120,000-kw
powerplant
is
the
first
under-
ground
power
installation
to be constructed on a
Bureau
project.
The
powerplant
chamber
is
a short
distance downstream from the dam in
the
left
abut-
ment and
about
400
ft
(722
m)
below the
ground
surface.
The Curecanti
Unit develops water storage and
hydroelectric
power
generating
potentialities
along
the
40-mile
(64-km)
section
of the Gunnison
River,
a
major
tributary
of the Colorado River. Other
major
features of the unit are
the
Blue Mesa Dam,
an
eerrthfill
structure,
and the Blue Mesa Power-
plant,
a
60,000-kw hydroelectric
installation, about
LZ miles
(19
km)
upstream from Morrow Point
Dam, and the
proposed
Crystal Dam
and
Power-
plant.
Construction
of Morrow Point Dam
and
Power-
plant
began
in
June 1963
under
a
$15,436,066
eon-
tuact awarded to the
joint
venture
firm
of Al John-
son Construction Company and Morrison-Knudsen
Company,
Inc.
Because of
the rugged
terrain
at the damsite,
access
to the
construction area
was
an
initial major
problem
to the
eontractor.
The
eanyon
walls rise
to
elevations
approximately
2,000
ft
(6L0
m)
above the
streambed;
the
lower 700 ft
(214
m)
of
the slopes
are
very steep.
To
gain
access
to
the crest
of the
dam and to the
powerplant,
the contractor con-
structed
more than
2
miles
(3,4
km)
of
roads. This
work
included extensive
excavation,
installation
of
concrete and
metal
crib-type
retaining
walls,
and
rock bolt stabilization.
In
all,
the
contractor
exca-
vated
more than
100,000 cu
yd
(76.455
ms) of
frag-
mented
rock
and stabilized the wall with
2,300
ft
(700
m) of
rock bolts
in lengths
varying
from 6
(1,8
m) to
20
ft
(6,1
m).
Before
beginning open-
cut excavation
for the
powerhouse,
the contractor
stabilized
the
higher
abutment slope on the steep
left canyon
wall. He removed
an additional
150,000
cu
yd
(114.683
m')
of
rock
and
stabilized the area
with 3,200 rock bolts having
an average length
of
10 ft
(3
m).
The
contractor
had
the option
of diverting
the
river through
flumes and
over the
blocks
of
the dam
or through
a diversion
tunnel
in
the
right
abutment.
He chose
to
construct
the diversion tunnel to
accom-
modate a maximum
anticipatect flow
of 13,500
cfs
(382mu/sec).
He
began open-cut
excavation
for
the
portal
in
October 1963,
and
sterrted
tunnel
excava-
tion
in November.
Conventionarl
drilling
and
blast-
ing
operations were
carried
on
:from
both
the up-
stream
and downstream
portals.
Excavation
was
completed in
January
1.964.
Concrete lining
opera-
tions were completed
;in
May,
at which
time
the
Gunnison River
was
di'yerted
around
the
damsite.
The circular
tunnel
is
2l
ft
(6,4
m) in
diameter
and about
1,200
ft
(361i
m) long'.
It
has
an intake
and outlet
headwalls
arrd a closiure
structure
to ac-
commodate
three bulklhead sections
which
are
to
be installed
when resiervoir
filling
begins.
The
tunnel
is
then
to be
permanently
sealed
with
^
concrete
plug
section.
The
tunnel
has
a rninimum thickness
of 9 in"
(23
cm)
of
concrete
linring,
excelct near
the closure
structure where
the lining
thicknr:ss is 4"5
ft
(1,4
m)
to
withstand
the
reservoir head
as high
as
300 ft
(91,4
m).
Voids
behind
the concrete
lining
were
backfilled with
grout.
,Rock
adjiacent
to and around
the closure structure
was
also
prressure
grouted.
In
July
1964,
the contractor: began
open-cut ex-
cavations
for
the dam
keywaysr
and for
the
power-
plant.
This work continued
thr:ough
the
remainder
of the
construction sesrson.
Because
of
the
severe
winter
climate at the site, all
surface
construction
work
was shut
down
from
December
through March
1965.
Excavation
for
the
dam's ahutments and foun-
dation
was completed
in
August 1965. Approxi-
mately
60 ft
(18,3
m)
of
perrneable
sand,
gravel,
cobble,
and large bouldlers were removed
from
the
riverbed to expose bedrock. \4/ith completion
of
exoavation,
the
profile
of the
dam was nearly
sym-
metrical.
The contractor then
grouted
the full width
of the
lower foundation at low'
pressure
through
a
curtain
of holes
50
(15,2
m)
to
'f0
ft
(21,3
m) deep
on
20-ft
(6,1-m)
centers.
Subsequent
low-pressufe
grouting
at
higher levels was
performed
through
the concrete as the dam constiruction
progressed.
Placement of
mass
concrete
in
the dam began
in
September
1965.
By'
the
end of the first season
of
placement-Novemb,er
27, 1.965-the
contractor
had
placed
about
43,000 cu
yd (32.876
m3)
of con-
crete.
Placement
of
r:oncrete l'esumed in
March
1966 and by the end of the
construction season in
November,
about
250,000 cu
yd (191.100
m3) hacl
been
placed
and sever:rl
sectionsi
of the dam stood
at about
360 ft
(110
m)
above
the foundation.
The dam
was divided
into b,locks
by
vertical
transverse
contraction
joints
radial
to the axis of
the
dam.
Placement
was
in 7.5-ft
(2,3-m)
lifts.
Each
lift was
placed
in layerst
22.5
in.
(57,2
cm)
thick. Spacing
of the
joints
rpas
40
ft
(I2,2
m),
except
for one 30-ft
(9,,1-m)
block. The
joints
rvere
-
[
'r
|
3'.11"
(1,
t Im)
Dlo.
ponrfoclr
730o
24
Q
'r
Spll
Oullrt
lrorhrocl
altuclura
-"
MORROW
POINT
DAM
(15r2a)
I
(tsr2a113g,a3y
(rs,?2)
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tunnrl
'r=//--t"bb
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(2129r03m)
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(1rttm)
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(2o98r55m)
THRU OUTLEiT
UORKS
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(t%1)
o
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t,,,,,uul-l-l----J
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(,2066rE5m.; (Q=r11,000
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]L
AC
SECTIOH
THRU
PENSTOCT
AND
POUER
PLANT
Ea. 6737.1(2o53ri6m)
MORROw.
SUMMARY OF
PRINCIPAL
FEATURES
Location
On
the
Gunnison
River, 22 miles
(35,4
km)
east of Mon-
trose,
Colorado
Purpose
Power
Owner
Bureau of Reclamation
Engineering
Bureau of Reelamation
Construction
By contract
Chronology
Construction
period:
1963-1968
(estimated)
Commercial
operation: unit l-Septemher 1968
(esti-
mated),
unit
2-December 1968
(estimated)
Reservoir
Total capacity
to elevation
7,160
ft
(2.182
m):
ac-ft
(mo
x 106)
117,000
(144)
Active
capacity:
ac-ft
(m3
x 106) 42,000
Surfaee area:
acres
(m2
x 101) ---. ----
800
Dam
Type: Concrete
double-eurvature thin arch
Dimensions-ft
(m):
nensions-ft
(m):
Structural
height
468
L2
52
720
Spillways:
Four
orifice-type
free-fall
spillways
at
the
top center
of the
dam, each controlled by
15-ft
(4,6-m)
by 16.83-ft
(5,1-m)
fixed-wheel
gates
Crest
elevation: ft
(m)
7,L23
(2.171)
Capacity
at elevation
7,165 ft
(2.184
m):
cfs
(m3lsec)
4,1,000
(1.161)
Outlet
works: One stainless steelJined
4-ft
(1,2-m)
square
conduit
through the
center
of
the dam
near the
base,
controlled by
two
3.5- by 4.0-ft
(1,L-
by 1,2-m)
slide
POINT
DAM
keyed and
grouted
to
assure watertig;htness
and
monolithie action of ther dam. Ilerte of
placement
in
any block
was
restricted so
tha'b
not
r10'r€
than one
horizontal lift could
be
placed
in 72 hou,rs.
Concrete
for the dam
was
(lesigned
to
obtain
a
compressive
strength
of
4,500
psi
(318
kg/cm') at
an
age of one
year,
which
is consider'ably
higher
than
the
Bureau had
flreviously
used in dam con-
struction.
About
four
saeks oli
portland
cement
(Type
II,
low
alkali)
per
cu
y(l
(225
kg/m') were
used
with a water-reducing,
set-retarcting
admix-
ture.
Maximum
size
of
aggrega,te
was A,yz
in.
(11,4
cm), a departure from
the
Bureau's
previous
prac-
tice
of specifying 6 in.
(16,2
crn.)
as the maximum
size of aggregate.
Concrete
placed
wa$ cooled
b,y wate,r
circulated
through
l-in.
(2,54-cm)
embedcted tubing
placed
on
the top of each, 7.5-ft
(2,2-m)
lift. About
59
miles
(95
km)
of cooling tulbing wars
thus
e,mbdded in
the dam. The contractor instralled
tw,o refrigera-
tion
units for
cooling.
One was used
to
produce
cold
water
for
cooling
the
placed
concrete.
The
other
unit
was
employed
to cool
the aggregate
and
to
produce
cold water
for the mix
plant,
thus main-
taining a maximum
tenrperature
of 60"
F
(15,6"
C)
for
the mix
as
placed.
Grout
holes
for a
main
gr:out
curtain
were
drilled
on
10-ft
(3-m)
eenters llrom
ther foundation
gallery
and from
tunnels
in
both
atrutments
to
depths
as
great
as
200
lt
(61
m).
A line
of drainage
holes on 10-ft
(3-m)
c€,nters were
drillerd
to depths
of
from
40
(12)
to 150 ft
(46
nr)
downstream
from
the
main
grout
curtain,,
For
placement
of
c,oncrete
in
the dam
and for
handling
of
materials, the conlbractor
installed
a
25-ton
(22.680-kS)
capacity, 1,400-ft
(,127-m)
long
cableway.
The
cablew'ay
headtower
\Mas\
on the
dam's left abutment
approximately
250
ft
(76
m)
above the elevation of
t;he
crest. The
tailtower race
on the
right
abutment was
450 fl;
(137
:rn) long
and
provided
access
over
t.he entire dam.
Capacity
of
the
buckets
u.sed in
placement
v/a.s 8
cu
;yd
(6,1
ms).
The
contractor completed excavation
of the
powerphant
chamber in April
1966.
The
powerplant
chamber is
206
ft
(62,8
m)
lonrg,
57
ltt
(17,4
m)
wide, and
varies in
height fro:m,
appro,ximately
65
ft
(19,8
m)
to
134
ft
(40,8
m). About
42,000
cu
yd
(32.113
m')
of
rock
were
exeavated.
Reinforced
concrete was
placed
wilbhin
the chamber
to support
the
generating
equipment. Ther walls
of
the
cham-
ber above
the
generator
floor
remain
as
exposed
rock.
The contractor excavated
the
powerplant
cham-
ber using the
"smooth
bore"
o:r
"cushion
blasting"
technique.
The technilque
requrired
blasting
the
peripheral
holes of
the
heading in
such a way
that
the
resulting
wall was as
unfractured
as
possible.
25
and
weir
cut for
powerplant
appurtenances
Excavation, all elasses,
for
powerplant
Excavation
for aecess, cable,
ventilation,
draft tube,
penstoek,
and adit
and dam
foundation
tunnels
Concrete
in dam
Reinforcing
steel
Steel for
powerplant
crane
runway
Penstocks
Gates
and
valves
Tubing
for
cooling
concrete
Rock
bolts
in
powerplant
ehamber,
a6cess
ind
cable
tunnels,
open-cut
excava-
tions,
and
penstock
and
draft
tube
tunnels
(52)
(324)
161,000
m3
116.448
126.916
16.820
160,000 114.683
46,400 34.?10
23,000 17.686
360,000
276.A10
lb
ks
2,601,000 1.134.436
316,000
142.882
1,234,000
569.733
1,050,000 476.n2
ftm
310,000
94.dgg
49,500
15.098
gates
Capacity
at elevation
7,165
ft
(2.184
m):
cfs
(m3/sec)
1,500
(42,6)
Power facilities
Location: Underground,
below left
abutment of Morrow
Point Dam
Nameplate
capacity: 120,000
kw
Number
and
capacity of
generators:
2
units at
60,000
kw
each
Maximum head: 405 ft
(123,4
m)
Major
construction
quantities
(estimated)
cu
yd
Excavation, common,
in
open
cut for dam, stilling
basin,
Excavation,
rock in open cut
for
dam, stilling
basin and
weir 166,000
Excavation,
rock,
in
open
cut for
penstock
intake
structure 22,000
Excavation,
all classes, in
open
Top width
rvraiximum uase
widtii----:-----------:
Crest length
26
MORITOW POINT DAM
The
roof
arch
and
side
walls of
the
powerplant
chamber
are supported
by
grouted,
expansion
anchor-type bolts;
more than
50,000
ft
(15.2a0
m)
of bolts
were
installed.
The
bolts
varied in length
from LZ
ft
(3,7
m)
to
20 ft
(6,1
m)
;
spacing was
on
4-ft
(1,2-m)
centers.
Wire mesh was
pinned
to
the
roof
arch to
prevent
small
rock
spalls
from
dropping out. A
suspended
metal ceiling was in-
stalled
the entire
length of
the
powerplant
chamber.
To
obtain
a better
indication
of the bolt
stress,
load-cells
were installed
on the
rock bolts
in several
locations
along the
arch and sidewalls. The
load-
cell consists
of a strainmetel
which
measures
the
elongation of the
bolt.
The
strainmeter makes
pos-
sible
c:omputation
of
initial
stress
in the
bolts.
In
addition,
the
strainmeter
will
detect any later
move-
ment
of the rock,
or anchorage
failure,
if
they
occur.
Another measurement
will
be made to detect
any
relative
movement of
the arch abutments and
side-
rvails by
use
of steel
plates
installed
directly oppo-
site
one
another
on the sidewalls and
securely
embedded.
The
distance
between
the
p'lates
will
be
precisely
measured
with a
tape and
tension meters.
Subsequent
measurements
will
indicate if
there has
been
any relative
movement
between
the two walls.
Measurement
of this
movement is
extremely im-
portant,
as the crane
rails for
the
plant's
250-ton
(226.796-ke)
capacity
overhead
traveling
cranes
will
have
to
be
adjusted
if
the
movement is ex-
cessive.
A
sonic device was
also installed
to detect and
amplify sub-audible noises
that result from
rock
movement. The
listening
device
was
employed
on
rveekends
and
during
periods
when construction
ac-
tivities were
shut
down.
Construction of
the
powerplant
was
carried
out
in
tu'o stages.
The
first stage
of
constmction,
part
of the
prime
contract
of the
dam, included
excava-
tion of
the
powerplant
chamber,
and
placement
of
concrete,
structurzrl
steel,
reinforcing
steel,
and
in-
stallation
of
the
traveling
crane.
Second-stage
construction is
nnder
a separate
completion
con-
tract and includes
installation
of the two 83,000-
Vierv of
underground
porverplant
during construction.
In-
teriol
portal
of the accesis
tunnel
is shown
;at
lower left.
horsepower
(81.865-rnetric
horsepower)
turbines,
generators,
transforrnrers, and other
electrical
equip-
ment,
as well as
other
finish
work.
Morrow Point Dam's free-f'all oriflice-type spill-
way
is
unique in the
Bureau
of
Reclamation's
ex-
perience.
Water
flowing
through
the liour
15-
(4,6-)
by
15-ft
(4,6-m)
openings
in
1;hLe
top central
part
of
the
dam
will
fall more
than,
350 ft
(106,7
m)-
about twice the
height
of
Ni:lgara Farlls--to
a
pool
retained in
the
reinforced-conLcrete
stjilling basin
at
the
toe
of the dam. /i 65-ft
(11],8-m)
high weir
320
ft
(97,5
m)
downstream fronr
the axis
of the dam
will
maintain
the
60-ft
(18,3-m)
deep
pool.
The
stilling
basin floor is about 5 llt
(1,5
m)
thick
and
about
160
ft
(48,8
m)
wide.
Iloman
l'. Wcnglcr,
Associatc Flcad
of Structural Department
Marcel
Bitouu,
Associate
and Assistant Head of
Planning
Division
Harza
Engineering
Company,
Chicago, Illinois
The
Mossyrock Project, currently
under con-
struction on
the Cowlitz
River
in
western
Wash-
ington
State,
is
owned by
the City of
Tacoma.
It
is
primarily
a
hydroelectric
power project
and
will
have additional
benefits
for flood control
and rec-
reation.
The dam
will
be about 606
ft
(185
m)
high
and
will
rank
among'the
world's highest
thin
arch
dums.
The
construction cost
of the
completed
Mossyrock
Hydroelectric Project
will be about
116
million dollars.
The
general
construction
contract
was awarded
to
Dravo-Johnson
combined
venture. The
planning,
design, engineering,
and
supervision of
construction
is
being
carriecl out by the
Harza Engineering Com-
pany
of Chicago,
Illinois,
U.S.A.
Hydrology
The Cowlitz
River
Basin receives
its
moisture
from the
Pacific
Ocean.
Mean annual
precipitation
varies
from about
60 in.
(1.500
mm)
in
the
center
27
of the
basin to about 150 in.
(3.750
mm)
at the limits
of
the
watershed.
Riverflow records
near
the
dam-
site are
available
for
a
periocl
of
over 30
years.
IVIean annual runoff
is about
5,4t00
cfs
(154
m3lsec)
and
varies
from
about;
1,500
clis
(42
m3/sec)
to
about 9,000 cfs
(254
m'lsec). Most
of
the
peak
flows
occur between November
and M;arctr.
Snow
melt contributes
to the
Spring
liloods.
The highest recorderd
flood
occurred in
Decem-
ber of
193:l with a
peak
oll
about 83,500
cfs
(2.360
m:'/sec).
Thc
spillwty design
flootl
wfts
based on develop-
ment of the
probable
maximum
sl;orm, with
addition
of estimated
snowmelt and
base flow contriibutions.
The
probable
maximurn flood
vrould h,&v€
a
peak
discharge
of 300,000
cfs
(8.496
m3lsec). A
flood
frequency
study was made by' the
basic stage
method
to estimate the magnitud,e of the floods
that
can
be expected during' construction.
River
diversion
River
diversion durjing
construction was accom-
plished
by diverting the entire
river
flow
through
two
unlined turrnels
in
the
left; abutmernt,
each
40
MOSSYROCK
HYDROELECTRIC
PROIEC'r'
Artist's sketch of conlpleted
lllossyrock
l'roject
shorving
dam,
spillwa]',
polverhrouse,
and reservoir.