United States Committee on Large Dams. U.S. Dams

Fixed

hoist

49.0'

-wq;r-:|

Et

s76.0

-.!

:lf1

NICKATACK

DAM

Top

of

gales,

Et

635.0(/9452

lrnr,

,,,r,

Min Tl,t/

Et s9L0

(/77.09-]

Thin clay

Draft

tube

Pipe

ga/lery-

c/ay

seam-a

€/

617.5(t&!i!!n)'1

..--.-

-

Fdn

drain

ho/es

54

60'

(/6,64n)

---@,zvd-

(HW

El

634.Q(/93,24)

/5.0'(4r57n.)

Cresf, E/ 5:95.0

(t8tr.lanl

Drainage

ga//ery

lE/

565.0(t7212/m)

drain

holes

t.--

Grout

curlain

/nlake

crene

AASE L INE

Gate

slof

Trash

t

sfoploq qutides

-

e DISTRIAUTOR

tl

594.0

(/8/,O5n)

El 560.5

(/76194m)

curfain

Max Ttl

El

63?.O

(t92,63n)-1

l-

75,73'

tzsPg4_

73.63'

I

/28.23'

39"O8n.

SECTION

-

SPILL'YAT

(/8r9n)

SEC

TION

-

POWERHOUSE

Grouf

Thin

b-

c

AUXtLtApr

LocK

I

//0.o8' /6.0'

')

r,roul

curlarrt

,,\Fi//ing

&

emplying

cu/veqfs

--- Grouf

SECTION

-

LOCKS

'tt/

!11.9.(/62,46

n)

9.O'

(4rggn)

'""t,1

f/ 645.0

(/96,6n)

c

ur

lains

NICKAIACK

DAM

39

6$,800

51.076

SUMMARY

OF PRINCIPAL

FEATURES

Location

Tennessee

river

miles 424.7

(683,5

km), 6.4

miles

(10,3

km) downstream

of

Hales Bar

Dam

(which

it will re-

place),

in

Marion

County,

Tenn., arnd 12.5 air miles

(20,1

air

km) from

Chattanooga,

Tenn.

Purpose

Flood

control, navigation, and

power

Owner

and

Operator

Tennessee

Valley

Authority,

Knoxville,'Ienn.

Engineering

Tennessee Valley

Authority,

Knoxville,'Ienn.

Construction

Tennessee Valley

Authority,

Knoxville,'Ienn.

Chronology

Construetion

started: March 1964

Reservoir filling

starts:

November 1967

Three

power

units

operation:

November 196?

Fourth

power

unit operation:

January

1968

Stream

flow

Drainage

area

(total

above dam):

sq mi

(mt

x 106) 21,870

(56.643)

Maximum

known flood at damsite:

cfs

(m3/sec)

-- 459,000

(12.999)

Maximum

probable

flood

regulated:

cfs

(m3lsec)

500,000

(14.160)

Average unregulated

flow

at damsite:

cfs

(m3,/sec)

38,000

(1.076,2)

Minimum daily

flow at

damsite:

cfs

(m3lsec)

3,300

(93,5)

Reservoir

Volume

at top

of

gate,

elevation 634 ft

(193,24

m):

ac-ft

(m3

x 106)

2;42,800

(300)

Pondage: ac-ft

(m3

x 106)

21,200

(26)

Aiea of

pool,

elevation

634

ft

(193,24

m):

acres

(m'

x

100) -- 10,900

(4.410)

Length

to

Chickamauga

Dam:

miles

(km)

46.3

(74,5\

Dam

Material and

type:

Concrete

gravity

spillway,

powerhouse

intake, and

navigation locks. Impervious rolled earth

fill embankment.

Maxirnum

height,

foundation to

deck:

ft

(m)

Outlet

facilities:

83

(25,3)

Spillway capacity

HW

elevation

634

ft

(193,24

m):

cfs

(m3lsec)

345,000

(9.7?0,4)

Spillway

capacity

HW

elevation 635 ft

(196,6

m):

cfs

(m3lsec)

500,000

(

14.160)

Radial

gates:

Ten 40

by

41 ft

(12,19

by

15,5

m), operated with

fixed

hoist--remotely controlled from

Chickamauga Dam.

froundation:

Interbedded shale and limestone

Power facilities

Intakes -4

(each

with

3 bays)

Gates-1 set, 2-wheel sections

for each bay

Powerhouse:

Gcnerating capacity, 4

units at

24,300 kw each

97,200 kw

Type

construction,

indoor-steel

frame,

precast

concrcte

panel

curtain walls

Turbines, 2 fixed-blade

propeller

and

2 Kaplan

(moved

from

Hales

Bar)

Draft

tube, elbow

type,

3 openings

Gates,

1 set, 1

slide

section for

each

opening

Govelnors,

twin

actuator

type

Watcrways, r'einforced

concrete

Switchyard:

Transformers,

2 banks with

three

single-phase 21,000-

kva

tlansfol'nrel's each

bank,

five bays, 161-kv yard

with

three

tr.ansmission

lines

Pow_e-rnlant

and

switchyard

remotely

controlled

from

Chickamauga

Dam

Navigation

locks

cu

yd

m3

225,000

172.036

pleted

lock

with

a

charniber

110

b,y

800

ft

(il3,b3

by

243,84

m),

comparecl

vyith

one lock

at Harles

Bar

with

a 60-

by 265-ft

(18,29-

by' 80,7?-m)

chamber.

All

underwater

portions

of

the

partially

completed

lock

will

be

constructed

so

the

lock

can

be

completed

in

the future

without

a cofferdam.

The

layout

of

the

dam

and

r:onstruction

scheme

presented

some

problernrs

TVA lhad

not

encc)untered

before. Because

river

traffic

at the

site

is

consider-

able,

it

was

necessary

to

develop

a construction

scheme

that would

minimize

bhe interruption

of

river

traffic.

Also,

the scheme

iadopted

shoutd in-

crease

the

tailwater

elevation

at Hales

Bar

Dam

as little as

possible

to minimize

the loss

of

power

generation

at

that

plant

durin[r construction.

The

rotating

parts

of the

two units installed

by

TVA

at

Hales Bar

are

to

be moved

to

Nickajack.

The

adopted scheme

requireril

that these

units

br: left

in

operation as

long

as

possible

and be installed

at

Nickajack

as

quickly

a,s

possitrle

to minimize

the

loss

of

power.

Another

requirelrnent was

to

con-

struct the

project

on iI

fast

schedule.

i.Tumerous

layouts and

construetion schemes

were

studied

to

find

the

most

economical solutions

to thesie

prob-

lems. The layout

of structures shown in

the

general

plan

and

a

2-stage

const;ruction

sr:heme were

finally

adopted.

\

AII

the structures,

except

tlhe right

embank-

ment,

are being

construcited in

the

first-stage

coffer-

dam. To

allow navigation

to

coltrtinue

uninterrrupted

and to

pass

flows

during

first-sbalge

construction,

a

660-ft-wide

(201,17-m)

channel vras

dredger:l

(total

of approximately 3,000,(f00

cu

y(l

[2.293.800

m3]

)

in

the

right

flood

plain

ax'ound

the right

end

of

the

cofferdam. The

cofferdam

and crhannel

are

dlesigned

to

pass

a flood

that

ma;y be exprected

to occur with

an average frequeney

of

once

every

threrg

years

(200,000

cfs

[5.664

m",/sec]

)

virithout

overtopping

the cofferdam.

The

channel has ia

minimum

depth

of

9 ft

(2,74

m)

for navigation.

(lonstruction

within

this cofferdam

is

expect,ed to be r:ompleted

1;o allow

flooding in

January 196ii,

at whiclh

time

all spillway

gates

will

be

open

to

pas;s

flow.

Navigation

will

be

1lhrough

the

partially

com-

pleted

800-ft

(243,84-m)

lock

clu,ring

second-stage

construction. After

a sufficient number

of first-

stage cofferdam

cells has been rernoved

to

pass

flow

and

navigation,

a

downs'tream

rock

dike with

layers

of

clay for sealing

and

an upstream cellular

coffer-

Concrete

Impervious rolled fill

Rieht embankment

Left embankment

Locks

Earth

excavation

Rock

excavation

Concrete

Powerhouse

and

intake

Earth

excavation

Rock

excavation

Concrete

Switchyard

Earth

fill

530,000

27$,000

6it,000

150,000

382,500

27,100

8€i,000

91.,400

405.238

2r0.265

47.405

114.690

292.460

20.72t

65.?56

69.884

Dam

and

spillway

Earth

excavation

Rocl<

excavation

182,500

30,200

139,540

23.091

40

NICKAIACK

DAM

dam

will

be constructed

across

the diversion

channel

and

will

become

part

of

the right

embankment

(see

section). The

area

between

the

dike and

the

cofferdam

will

be

unwatered

and the earth

embank-

ment

completed

by

November

1967.

During

second-

stage

construction

the tailwater

elevation

at

Hales

Bar

will

be increased

a maximum

of

b

ft

(1,b2

m),

with

all

available

units

discharging.

at capacity.

An

economic

study

of

power

losses

at Hales

Bar

due

to

decrease

in head,

compared

with

additional

construc-

tion

cost

at

Nickajack

for

reducing:

the head

loss

at

Hales

Bar,

showed

that

the

additional

construction

cost was

not

justified.

The

removal

of

the first

unit from

Hales

Bar

begins

April L, IgG7,

and

the

second

unit,

June 1,

1967.

Final

closure

is expected

to

take

place

around

November

l,

1967,

and

will

be

accomplished

by

the

closing

of

the

spillway

gates

and

placing

a steel

bulkhead

across

the

temporary

ope:ning

in the 800-ft

(243,84-m)

Iock.

Navigation

will

be interrupted

only a

week

or

two

during

closure

and

filling

of the

Nickajack

Reservoir.

After

the r,eservoir

is

filled,

navigation

will

be

through

the

completed

600-ft

(182,88-m)

lock.

AIso,

three

of the

four

power

units will

be available

for

generation

and

the fourth

unit will

be completed

by

January 1968.

The

dam

is

founded

on

interbedrled

limestone

and

shale

dipping

approximately

7 dregrees

upstream.

Under

the downstream

portions

of the Iock

walls

there were

several

nearly

vertical

solution

channels

,.1

View

looking

upstrea,m showing

55-acre cofferdam

extending

across

main river

clharnnel.

I)iversion

channel at left.

and

clay seams along

the

bedding

planes

in

the upper

part

of the foundation. Considlerable excavation was

required to

place

the

'walls

on

firm

rock.

'Under

the

spillway,

powerhouse,

and the

upstream miter sill

and

gate

blocks of

the

locks were

paper-thin

clay

seams

in

the

bedding

planes

b,etween

very smooth

flat

rock surfaces.

llhe spillu'ay and

powerhouse

structures

were

keyecl into thre

rock

belorv

any

po-

tential

sliding

p,lanes

1;o

increasre

the

safet:f of those

structures

(see

sections).

Thr: upstream

lock miter

sills

were also

keyed

into the

foundation and

into

the

adjacent

lock wall

blocks.

Otherwise,

the

struc-

tures

are conventionall.

The filling

and

emptying

system

for

the

locks

is

relatively

new.

It

consists

o:f two

rows of

10-in.-

diam

(25,4-cm) ports

conner:ting the

culverts

in

each

lock wall to

concreteJined

trenches

in the

lock

chamber

floor

(see

section).

'lVA

first used

this

system

at

Wheeler

A.uxiliary lock

in L9li2,

and

it

gives

a very smooth

and

fast; filling

and emptying

of

the chamber.

The

interior mass concrete

was

designed to

have

a

Z-in.

(5,08-cm)

slunrp

and

a

compressive

strength

of

2,000

psi

(140,62

kg/cm')

at;

the age o:f

90

days.

It contains 6-in.-maximum

siizze

aggrega,te

(L5,24

cm),

128 lb

(75,92

kel/m') of

llortland

cement,

153

lb

(90,75

kglm')

of

fly

ash,

and 135 lb

(80,07

kglm')

of

water

per

cubic

y'ard.

It

also contains

neutralized

vinsol-resin

air-erntraining

agent

and

lignin base water-reducing

ogrent.

OROVILLE

DAM

Alfred R. Golze, Deputy

Director

Donald H. Babbitt,

Senior

Engineer

California Department

of

Water

Resources

Oroville

Dam,

the

primary

storage feature

of

the

State of California's

Water

Project,

will

be com-

pleted

in

October

1967.

The

770-ft

(235-m)

high,

zoned

earthfill

dam

will

impound

3,500,000

ac-ft

(4.300

x 10"

m")

of

water

to supply irrigation,

iltr-

nicipal,

and industrial

needs

;

to

generate

power;

to

provide

flood control;

and

to create a recreation

lake.

The

80,600,000

cu

yd (61.600.000

m3)

embank-

ment is

being

placed

at

an

avera,ge rate

of approxi-

mately

100,000

cu

yd (76.000

rnLB)

per

day.

The

dam, located

on

the Feather River

in

the

first

range

of the

Sierra Nevada

foothills

above the

Great

Central

Valley

of

California, is founded

on

a

fine

grained,

very

hard,

dense

anrl

generally

massive

meta-volcanic

rock

containing

some narrow

bands of

schist. Also

present

are

shear zones

which,

when

examined

by

core

drilling

and

excavated

adits, were

found

to be capable

of

satisfactory

treatment.

Strip-

ping

to

a sound

foundation

for:

the

embankment

General

vierv

from

dorvnstream

showing

the

spillrvay:

(1)

chute,

(2)

flood

control

outlet,

(3)

end of overpour

scction;

(4)

conveyor

belt and hopper;

(5)

surge

pile; (6)

diversion

tunnel

portals; (7)

penstock

intake;

(8)

Bidrvell

Bar

Bridge;

and

(9)

i,eservoir

clearing.

required

the

removral

of

all soil

and

str:trngly

weath-

ered rock.

The

avel:age

excavated

depttr

of this

ma-

terial

is 14

ft

(4,3

nr),

with

a maximum

depth

in

the

axis

core

trench

of

nearly

1010

ft

(30

m,)

in

a major

shear

area.

The zoned

embankment,

shown

in

rsection,

was

chosen

after

extensive

studiers

of different

types

of

earth, rockfill,

and

concrete

dams.

The

selection

was

dictated

by

foundation

conditions

at

the site

and by

the

abundant

source

of ideal

pervious

embankment

materials

that had

been

prodluced

by

dr.e,dgers

work-

ing

over

the flood

plain

of

the Featherr

River

for

gold.

This

gravelly,

cobbly

material,

known

as

dredge

tailings, lies

in vast

fields

10

to

15

miles

(16

to

24

km)

downstreaffi

of

the dam.

llhe

tailings,

deposited

in

depths from 15

t,o

50

ft

(4,6

to

15,2

m),

are underlain

by arnother

irroduct

of

the

dredging

operation,

partially

washed

sand.

Thisl

sand,

when

combined

with

the coarse

tailings,

forms

the

tran-

sition

zones

of

the

dam.

A

oleposit

of clays

and

silts

adjacent

to

the main

borrolv

area

provides

the

im-

pervious

core

matelrial.

Tlhe

only

processing

re-

4T

42

OROVILLE

DAM

FEATHER

TIVER

TUIIIIEL

LITIT9 OF

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FILL

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T'EASUREAIEHf

SAAAtEn

SUMMARY OT' PRINCIPAL

FEATURES

Location

On

the

tr'eather

River

in

Butte

County,

California

Purpose

Power,

public

water

supply, floorl

control,

irrigation, rec-

reation.

Owner

State of

California

Engineering

California

Department

of

Water Resources

Construction

Oro Dam

constructors

Chronology

_Dqm _completion:

Oetober

196?

(estimated)

Initial

power

installation

operation:

lg6g

(estimated)

Reservoir

Capacity: ac-ft-(m3

L.10r)

8,b00,000

(4.800)

Area:-.acres

(_*t

I10:)

_-

-_

.

15;b00

(O.2ZS)

Shoreline:

miles

(km)

- -

'767

'

(269i

Dam

Type:

earthfill

Dimensions: ft

(m)

Height

770

Base

width,

maximum

section

8,b00

OROVILLE

DAM

t0,7

tl

t20.' 6n

quired,

other

than a minor

amount

of moisture

co:n-

ditioning, is

screerning

this

core

material

to remove

rock

over 3 in.

(7,6

cm).

With reference

to

the section,

the

embankmellt

materials

are:

Zones

I, IA

arnd

IB-lrnpervious

core

from

t]re

deposit

adjacent

to the

mtriln

borrow

alrea,

consistirrg

of

well-graded

mi:rture

of cJlays,

silts,

sands,

gravells,

and

cobbles

to

3-in.

maxilmum

size.

Compacted in

10-in.

(25,4-cm)

lifts

by 100-ton

(90-metric

ton)

pneumatic

roller.

Zones

2

and

2A-Transition

zonos

consisting

of

well-graded

mixture

of silts,

sands,

gravels,

cobbles,

and

boulders

to

15-in.

(,38,1-cm)

m,aximum

size.

Compacted in

15-in.

(38,1-crm)

lifts

by

smooth-drum

vibratory

rollers.

Zone

3-Shelll zone

oil

predomirnantly

sands,

gravels,

cobbles, and bo,nl,ders

to 24-in.

(6l-cn:r)

maximum

size.

flp

to

25

percent

minus

No.

4

US

Standard

sieve

sizes

perm,itted.

Compacted

in Z$-ist.

(61-cm)

Iifts

by smooth-clrum

vibratory

rollers.

Zone

4-Impervious

core

from

sel,ereted

abutment

stripping.

Must

contain

berbween

lb

and 4b

percent

passing

No.

200

US

Strtndard

sieve,

with

g-in.

(20,3-cm)

maximum

size.

Compar:t;ed

in

10-irn.

(25,4-cm)

lifts

b:f 100-tc,n

(90-metric

ton)

pneu_

matic

roller.

Zone

4A-Bullfer

zone

designed

to

compress,

with

same

grading

requirerments

as

Zi,ctne

4,

but less

stringent

compact;ion

requirements.

tOompacted

in

15-in.

(38,1-cm)

lifts

by

smooth-drum

vibrator,y

roller.

43

(236)

(1.067)

(2.110)

(275,2)

(61.600.000)

(18.400)

(L.s42)

(1.403)

(10,7)

(6.300)

(33,6)

Power

facilrrres

Location:

Underground

in left

abutment

of

dam

Initial

installation:

420,000

kw

(B

Francis

turbines

at

110,000

kw

each

and

1 reversible

Francis

pump

turbine

at

90,000

kw)

ultimate

installation:

600,000

kw

(2

additional

pump

rur-

bines)

Average

head:

ft

(m)-600

(249)

lengt! _I!o.

I-ft

(m)

-_____________-_

4,400

!,gngth

No.

2-ft

(m)

_____________-_

4;600

Diameter-ft

(m)

-

BE

Combined capacity:

cfs

(m3/sec)

190,000

Maximum velocity:

fps

(m/sec)

-----------

110

9+e

u

EL 299.5'

I

a,rl

rl

to.o'

ct.a n

5.0

tta,4

u

EL 2il.t7

/.ccfss

E/ILEPY

UN'IATERINC

G/LLEPY

sEcnoN rHPouGH

I

uutrs

44

Zones 5A

and

5B-Drainage

zones consisting

of

gravels,

cobbles,

and

boulders

with. maximum

of

12

percent

minus

No.

4

permitted.

Compacted

in 24-in.

(61-cm)

lifts

by smooth drum vibr:atory

roller.

The

sloping

core

section chosen

for the

dam

was

estimarted

to

be

slightly

mol'e expetrsive than

a

verti-

cal

core section,

but

it

provides

more

favorable

geometry

for

settlement of the Zone

1

material

with

relation

to

Zones

2 and 3,

which

are

both

consider-

ably

less compressible

than

Zone 1 material

under

the

hish loads

to

be

experienced

within the

darn.

Settlement

and

stress

measurements

made in

the

embankment

during construction

are

verifying the

wisdom of

the

sloping

core

sectionL

selection.

An

important

feature

of the

dam

design

is the

concrete

core

block on

which the

impervious

core

rests.

Its

long term

purpose

is to

eliminate

differ-

ential

settlement

problems

by

filling with concrete

the deeply

incised

"inner

gorge"

oll the

river valley.

This concrete

base

provides

a uniform

surface

of

large extent

to support the core.

11;

also

averted

the

problem

of

beginning

the

impervious

core

in a

deeply

incised

and

irregular area

in

which

constricted

working space

would

tend

to make

proper

placement

and

compaction

difficult.

The concrete

block

with

its

50-ft

(15-m)

high

parapet per:mitted

placement

of

1,900,000

cu

yd

(1.450.000

m') of embankment

material

in the upstream

portion

of the

streambed

during the

1963

construction

year.

This substan-

tially

reduced

the

quantity

of

embankment

material

required to

be

placed

during the

r:ritical 1964

con-

struction

year.

A cement

grout

curtain

with

a

maximum depth

of

200 ft

(61

m) was injected into the

foundation

beneath the

core. A reinforced concrete

gallery

was

constructed

in

a trench excavated into the rock

foundation for

the

core. This

gallery

was used to

expedite the

grouting

operation

during construction

and to

accommodate supplementall

grouting,

if re-

quired,

after

the dam is

constructed.

Drain

holes

with a maximum spacing

of 80 ft

(24,4

m)

on

centers,

were

drilled 40

ft

(12,2

m)

into

the rock

downstream

of the

grout

curtain

from

this

gallery.

Oroville Dam

is

probably

one

of

the

most

highly

instrumented

earth

embankments iln

the world. The

purpose

of this

extensive

instrumentation

is

to

per-

mit

detailed

observation

of this

dam

of unprece-

dented height

both

during

construction

and

opera-

tional

phases.

The

prime

construction

contractor

is

installing

&

network

of

pressure,

tubing, electric

cable,

and mechanical

devices

in

the

embankment,

and

connecting

and

installine

all sensors

and

moni-

toring

equipment.

Parameters to

'be

measured

are:

embankment

pore pressures;

embankment

settle-

ment

and horizontal

movement;

static

and dynamic

stresses

in

embankment;

stresses

and strains in

and

on

the surface

of the concrete

corre block

and

grout

gallery,

temperatures

in

the concre,te,

rock,

and

soil;

seismic

acceleration;

and seepage.

A

rigid construction

sched'u)e,

with

in.termediate

control

dates

for

mantlatory

e:mbankment;

elevations

and

two

35-ft

(10,'I-m)-dianr

diversion

tunnels

provide

river management

cluring construction.

During

1963,

embankrnent

placement

was

limited

to

the

volume upstream

of

the

core block below eleva-

tion

290 ft

(88,4

m). This resl;riction

was imposed

to

minimize loss of

fill

by

erosiion

during

the

winter

of

1963-64

when river flow

wals

expected

to exceed

the

capacity of

Diversion Tunn,el

No.

1 anrd overtop

the

core block.

Flows

occurring

that wi:nter were

unusually

low,

and the

core

block was not

over-

topped.

During construction

year

7964, Diversiion Tunnel

No.

2

was

required tc,

be comp,leted.

Thr: upstream

portion

of the embanhment

was required

to be con-

structed to elevation

605

ft

(184,4

m)

by

.November

15,

1964, so as

to

pasis

the Slfa,ndard

Pro;ject Flood

(frequency

of

1 in

4t50

years),

with

the two

di-

version tunnels

then

jin

servic,e,

In

December

1964,

the

maximum

flood of

record occurrerl,,

and

the

partially

completed

Oroville

l)am,

bypassing

the

river through the tviro

diversiion

tunnels, reduced

peak

flows on the

Feather Riiver by

approximately

100,000

cfs

(2.832

m3,/ sec),

prrrventing

zut;

least

$30

million

in flood

damages to

property

do'wnstream.

Closure of

Diversion

Tunnel

No. 2

was

effected

during

the summer of'

1966,

leraving

Tunnel No. 1

to

handle river flows. Before the

winter runoff of

1966-67 began,

however, the dlam was

r:onstructed

to elevation 700 ft

(2L3,4

m), which is

high

enough

to

pass

the

Standarrl

Project Flood

thr:ough the

single tunnel remaining

in lserrvice

withLout

over-

topping the

partially

completedL structurr:.

Diversion Tunnel

No. 1 is

scheduled for

closure

in

October of

1967,

at which time

the darn

is

to be

topped out at

elevation

922 ft

(1181

m)

to a, height

of

770

ft

(235

m).

The

greatest

challenge

in

constructing Oroville

Dam

is

excavating,

lhauling, ernd

placing

the em-

bankment at the

schteduled specification rate.

To

meet this challenge,

'l;he

cont:rauctor, Oro Dam Con-

structors,

is

using a specially d,esigned

bucket wheel

excavator to dig the

,clr'edge

tailingS, &

prrivate

rail-

road

system constructed

to tt:a,nsport the

materials

in trains of

gondola

cars an average of'

11 miles

(I7,7

km)

to the damsite,

an automatic c,Dut dumper,

and an elaborate system.* of

conveyor

belt;s to

handle

the

materials

at the damsite.

Nearly two-thirdsl of

the

dredge

tailings are

being excavated

by the bucket

wheel

excavator.

This mammoth machine,

weighing

668 tons

(600

metric tons), digs

material at a rate

of more

than

5,000

tons

(4.500

met:ric

tons)

tcer

hour. It

is

100

ft

(30,5

m) long, 45

ft

(13,?

m)

high, ilnd

44

ft

(13,4

m)

wide.

The

rotating

'wheel

is

30 ttt

(9,1

m)

in diameter

and carri,es

eight b,uckets

ea,llh

having

a

capacity of 1.8 cu

yd

(1,4

ms,). It is

elect;rically

op-

erated and self-propelled,

mo'ring

on cravrler

tracks

OROVILLE

DAM

OROVILLE

DAM

45

7.5

ft

(2,3

m) wide

and 34 ft

(10,4

m) long. Exca-

vated material is delivered

by

conveyor

belts

mounted on

the

wheel

excavator to a

companion

machine, a

265-ft

(81

m) long

transfer

conveyor,

which feeds

into

the

skid mounterd

field conveyor

system

for transportation

to train

loading stations.

The

conveyor

has

a

54-in.

(1,4

m)

wide steel rein-

forced rubber

belt and

extends as

much as

2

miles

(3,2

km) in the borrow area.

The train

loading

stations

were constructed

above

ground

and consist of steel

arnd

timber

tunnels

through

which the trains

pass.

Material

is

belt

delivered

to

a surge

pile

overlying

the tunnel and

is

fed

into 10

hoppers

equipped with automatic

gates

positioned

so

as to fill 10

gondola

cars simultane-

ously.

A

40-car

train

can

be

loaded in

about

I

minutes.

The wheel

excavator

is supplemented by

two

11

cu

yd

(8,4

m") draglines and

a

fleet of

100-ton

(90

metric tons)

capacity

bottom-dump

trucks. Material

loaded into the

trucks is hauled

to

a

train

loading

station

identical to

the one

fed by

the

wheel

exca-

vator.

The trucks

dump

into

a

Jropper feeding

a

conveyor

ramping up to

an overhead

shuttle

con-

veyor

which

distributes

the

material

to the

10

hop-

pers.

The draglines also selectively

excavated the

cleaner

coarse tailings

required far

Zones

5A

and

58 and

the

partially

washed

sands

which are blended

with coarse tailings

at

the damsite

to

form

Zone 2.

The impervious

Zone

1 materia,l is

excavated

by

50 cu

yd

(38

m") scrapers

push-loaded

down a 3 to

1 slope.

The scrapers dump

into

hoppers

feeding

two

vibrating

screens

where

the

material

over

3-in.

(7,6

cm)

is

removed

and

belt conveyed

to a

holding

bin

for

truck

haul either

to

waste

or,

if it is sufficiently

clean,

to

use

in

Zone

3.

Material

pzrssing

the screens

is belt-conveyed

to a shuttle conveyor that dis-

tributes

it to

10

metal bins from

'which

10 railroad

cars can be

simultaneously

loaded. The

800-ton

(720

metric

tons)

storage capacity

of each

bin

provides

the

necessary surge

storage

for

train

loading.

All borrow

material is hauled

to the dam by

railroad.

The

railroad

system was designed,

built,

and

is being

operated by

the contractor on right-of-

way furnished

by

State.

To minimize

the dis-

turbance

to the City of Oroville,

the

route follows

the

Feather River

channel

and

three

temporary

bridges across the stream were

required.

The trains

are made up

of

forty-two 55

cu

yd

(42

m'')

gondola

cars

pulled

by

two

large

diesel elec-

tric

locomotives

operating

in

tandem. The loco-

motives are rated at

2,500

horsepower

each. Six

locomotives are continuously

in

service during haul-

ing operations. One

spare locomotive

is

on

hand so

that routine maintenance

can

proceed

without

in-

terrupting

hauling. Three sets

of

locomotives keep

four trains

shuttling back

and forth between

the

borrow arel"

and

the

car

dumper at

the

damsite.

To

maintain a continuous flow of materrials to the stock-

pile

at the

damsite,

one

train

lhas

to be continuously

in the

process

of

being: dumpecl, which

is

thLe limiting

factor

in

the

entire

materialls handlinll

system.

While

one

train

is

being

durnped,

the

ot;her

three

trains

are enroute or

are being

loaded

at the borrow

area.

A

trainload

of embankmenrt

material

arriving

at

the

car

dumper

nearbhe damsite

is

spottr:d so that

the

first two

cars

are

positioned

withirn

the car

dumper.

The

locomotive the:n

uncouplers,

proceeds

up

the

tail

track,

couples

to a string

of empty

cars

waiting there

and returns the

empties

to the

borrow

area

loading stations.

Meanwhile,

the automatic car

dumper

handles

the

loaded

train

indepe:ndently. It

rotates

two

cars at a

time to

dump the load,

then

rights them,

and

mo'ves

the entire train ahead to

position

two

more caris

in

the

dumper, re'peating

the

cycle,

until all

cars are

dumpeil.

Cars

ar:et equipped

with

rotating couplin,gs

so that

it is

nolb necessary

to

uncouple the

cars :for dumping. When unloading

is

completed,

the

dunnper's

prnsher

arm

prushes

the

train

from

the dumper

and

it rolls by

grarrity

to

the

tail

track.

An arrester

on

the rails

anLd

reverse

grade

at the

end of

the tracks

brings thr: train to

a

stop

where

it wai-ts for the

locornotive frorn the next

train.

All but

the

last two

cars

oli

each train are

loaded.

The

last

two

cars

of

n

train

cannot be dumped, but

are

needed for

positiorning

and

holding

the

preceding

two

cars

while

being dumped. Since the trains re-

verse direction eerch trip, the brvo cal's oni either end

of the train

are

loade,d

on altercnate trips,

The car

dumper

discharges

on

a

series

of

96-in.

(2,4-m)

and

'tr2-in.

(1.,13-m)

conrreyor belts

which

cross the

river to a

sur:eie

pile

over a

reclaim

tunnel.

This

tunnel

is

a

20-'ft

(6,1-m)-diam

steel

arch

and

has

38

gaters

and

feeding

charqrels whicli

discharge

onto a 72-in.

(1,8-m)

conveyor belt within

the

tunnel.

A

self-porvered

stilcker mounted

on rails

receives material from the

car dumper

anrcl traverses

the

length

of the

reclaim

tunnel to delirrerr the ma-

terials

to their

propet'

stockpile

location,,

The

im-

pervious

Zone 1 material

)bypasses

the

reclaim

tunnel,

feeding

direcl;ly

onto

ar belt leading

to the

dam

area. The transition

Zone 2

material is manu-

factured

at

the

reclairn tunnel

by

dischar:ging

proper

amounts of the

sand ilnd

coarse dredge

trailings

onto

the

belt.

The

surge

pi,le

capacity

is

the equivalent of

more than one-day's

placemenl,.

From

the

reclaim

tunnel

rstockpile,

tlhe

material

is routed up the

72-in.

(1,8-m,)

conveyor

belt

system

on

the

right abutmetrt of the

dam and discharged

into a

1,000-ton

(9O?-metric

ton)

capacit,y

portable

steel

hopper. The hopper

loa,ds 100-ton

(9O-metric

ton)

capacity bottom

dump t:rucks

which carry

the

material to

its

final

position

o,n the dam.

The wind-

rows

left by

the trucks

are sp:rerad by bul)titozers into

the required

lift

thicl<nesses.

46

The transportation

system delivers only one type

of

material at a time;

trains

do

not

carry mixed

loads.

Intermittent delivery in

trainload

lots

of dif-

ferent type

materials

are readily accommodated

by

the

simple expedient of moving

the

stacker to the

proper

location over

the

reclaim

pil:.

Only

one type

of

material can be

delivered at

a time

to

the

dam;

the

change-overs

can

be

readily

made by altering

withdrawals

from

the

stockpiles

over the

reclaim

tunnel.

The

contractor has

maintained, with few

excep-

tions,

rr

placement

rate of about

500,000

cu

yd

(380.000

m")

per

week.

Material

is excavated

in

the

borrow

areas and hauled

to

the

dam 6 days

each

week

and

placed

on

the

dam

5

days each week.

The

hieh degree of mechanization

and automation

em-

ployed

by the contractor has resultred in

a compara-

tively

sinall work

force at

the site.

A normal

complement

of

about

500

men

are

required for

the

three

shift

operation.

Alternate

schemes

for

excavating

and

hauling

the

embankment

material were

studied

by the

State

and the

bidders on the construction contract.

Most

of

the schemes

included

railroad

haul.

The high

capital

investment cost

eliminated

the

possibility

of

nsing

a

belt

for

the entire

length

of

haul.

The cost

of

a

high

speed road required

for

t;ruck

haul, along

with

climatic conditions,

ruled

out

this alternative.

The

daytime

temperatures in

the Oroville area reach

100" F

(38'

C) for

about

a

month

each summer.

The high speeds which

would

be necessary for

trucks

moving

over

the

12

miles

(.[9,2

km)

at

that

high

temperature were

considered

too difficult serv-

ice

conditions

for

tires

presently

available.

In

the

winter,

the

area

is

also frequently

shrouded by fog

which

would

require

the trucks

to

reduce

their

speed.

In

addition to the high

dam, the Oroville

de-

velopment

includes

an underground

powerplant

in

the

left

abutment. This

plant,

shown in

section,

contains

three

pump-turbines

and

three

conventional

turbines.

It will

be

operated

on

the

pumped-storage

principle,

along with

its

companion Thermalito

Powerplant,

to

produce

a

combined

output

of

710,000

kw of high value

peak power.

'Water

will

drop

through the

Oroville

plant

under

an

average

head

of

600

ft

(243

m),

passing

then

t)rrough

the

Therma-

lito

Powerpnant for an

additio:nal

100-ft;

(30,5-m)

drop.

The Thermalito

Afterba:y will store

lbhe

water

so that

it can be

pumped

back

into

Orovillle Reser-

voir off

peak

and released

dolvtr the

Feather

River

and

into

several

irrigation

canals at closely

con-

trolled

rates. The diversion

damr

pool,

the canal, and

the

Forebay

will, in effect, operate

as a canal

and

have

a

common

unclnecked

(nearly

level)

water

surface.

The

two

diversion

tunnels

are

being

plugged

in

the

upstream

portion,

and

the

olownstrea:rn

portions

are

being converted

for

use

as tailrace turnnels for

the

underground

plant.

The

intake structrure

for

the

penstocks,

quite

separate

frorn the

dive,rsion

tun-

nels, contains

a shuttrlr

systern to contrc,l the

level

and

hence

the

temperature

zone from wh.ich

water

is

drawn

from the

rr:servoir.

This control is re-

quired

to meet the

needs of do'wnstream

fishery and

rice

growers.

The

spillway

for Oroville

llam is

essentially

two

distinct

structures.

One

structure, the

"flood

con-

trol

outlet,"

consists

of

a

he:lclgate structure con-

taining

8

top

seal

radial

gatesi,

17

ft 7

in.

(5,4

m)

wide

by 33 ft

(10,0

nr) high,

rvith a

1713-ft

(55m)

wide by 3,500-ft

(1.066-m)

long

concrete .lined

chute

terminating

in

an energy

absorbing

bur:)ret. This

structure,

combined

''rith

a flood control

storage

reservation

of

750,00{0

ac-ft

(925

x

100' fiI3), will

control

the Standard

lProject

lFltood with

ar,

peak

in-

flow

of

450,000 cfs

(L2.750

nr"/sec) to an outflow

of

150,000 cfs

(4.250

m''lsec).

The other

spillway

structure,

a

1,730-ft

(1i26-m)

lottg concrete overpour

section,

when combined

with the

flood

control out-

let can

safely

pass

the

spillway

design

flood, which

has t

peak

inflow of

720,000

r:fs

(20.000

m3lsec).

The crest

of this

structure

isi set at

elevation

901

ft

(274,6

m), one

ft

(0,3

m) above norrnal water

surface.

Oroville

Reservoir

required the

reloca,tion

of a

transcontinental

railroad, a

rnajor

Statel

highway,

and other County

roads

from

the

Fea'bher River

Canyon.

The tunnels

and

bridges required for

these

features

are major st;ructuresi

themselvers.

OROVILLE

DAM

R-OUI\D

BUTTE DAM

ltound

Rutte

ll)am

and Porverhouse.

*,;.ir.-

t-t.,.'-

tHs

$$:';.'

."

,ili'r';:i;

:i':!-:..:i'.

lyiti;i'

r::ii

,i

.

i-,

.:.

[iie^*..

r17'..'i

.

^;,

,l$:ii:

^i*':'

;...TTF.

0. E. Walsh, Brig.

General,

USA Ret.

Fonirerly

Chicf

Engineer,

Portland

General Electric

Co.

Round Butte Dam

is

a rolled

rock

fill

dam

with

an

impervious

central

core

protected

by

three filter

zones

on both up

and

downstream

sides.

The dam is

located

on

the

Deschutes

River

about

110

miles

(177

km)

south

of

its

confluence

with

the

Columbia

River.

The site

is

about one-half

rnile below

the

mouth of the

Metolius

River

and something

more

than a mile below

the

confluence

of the

Crooked

River

with

the

Deschutes.

It is

abourt

10

miles

(16

km)

southwest of Madras,

Oregon.

The

selected site was

the

only one found where

the dam abutrnents could rest

on the original canyon

walls.

The

Deschutes

Itiver

Canyon

at

the

site is

about

900

ft deep,

and :is the se,cond

cuttinLpr

in

the

same

general

area

of

a

canyon w'hich

had

been

filled

almost to the original

canyon rim level

b1r

a later

lava

flow.

The base foundation is

on

ltelton

basallt under-

lain

by Columbia

River

'basalt.

lthe

Pelton

brasalt is

covered

with various layers

of s,r-called

Deschutes

sediments interlain

withr

three trasalt

flows. In

the

general

vicinity

all stral;a are esisentially horizontal

and show

practically

no

local

se.ismic

distu,rbance.

Round Butte,

a

volcanir: cone, .lies

about

o.ne mile

east

of the damsite.

Extensive

core

drilling and, explorato;r;y

adits

were used to define

the axis and refine

design.

The

47

United States Committee on Large Dams. U.S. Dams

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