06 Aqueducts

7/29/2019 06 Aqueducts

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Monroe L. Weber-ShirkSchool ofCivil and

Environmental Engineering

Aqueducts
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Where Are We?

We estimated the land area needed to

supply water to NYC

How large a pipe is needed to carry the

water to NYC?

We will look at the construction of the Catskill

AqueductWe will figure out how large a pipe is needed to

carry the water from the Delaware system


3/36

Aqueducts

How does NYC get the water from upstatereservoirs down to the city?

Pressurized TunnelsDeep pressurized, bedrock tunnel

water flows under pressure just like in the pipes inyour apartment

Grade TunnelsNot pressurized

water surface is in the tunnel

water flow is similar to water flow in a stream


4/36

Supply Aqueducts and Tunnels

Shandaken Tunnel (1928)

Catskill Aqueduct (1915)

Delaware Aqueduct (1944)

Neversink Tunnel (1950)

East Delaware Tunnel (1954)

West Delaware Tunnel (1967)


5/36

Types of Aqueducts

Following natural surface

open channel cut-and-cover

Above natural surface

embankment

viaduct

Below natural surface

grade tunnel

Following or above

natural surface wooden pipe

reinforced concrete pipe

steel pipe

plastic pipe Below natural surface

pressure tunnel

On Hydraulic Grade Below Hydraulic Grade


6/36

Profile of Catskill Aqueduct

Small Scale profile of Catskill Aqueduct, AshokanReservoir to Silver Lake Reservoir. (White p. 46)


7/36

Cross-section of Cut-and-Cover

Aqueduct

Construction of cover embankment. Rock was usually excavated to a 6 on 1 slope. Minimum

thickness of concrete along sides 20 ins., but usually thicker owing to disintegrated condition ofsurface rocks. (White p. 50)

Cut and Cover


8/36

Delaware Aqueduct

10 km


9/36

Flow Profile for Delaware

Aqueduct

Rondout Reservoir(EL. 256 m)

West Branch Reservoir

(EL. 153.4 m)

70.5 km

(El. -183 m)

Sea Level

(Designed for 39 m3/s)

Hudson River crossing

Valves to control flow?


10/36

Size of the Delaware Aqueduct

How big does the tunnel have to be?

What variables do you think are important?


11/36

Simplified Delaware Aqueduct

Rondout Reservoir(EL. 102.6 m wrt West Branch) West Branch Reservoir

70.5 km

(Designed for 890 mgd

or 39 m3/s)

Hydraulic Grade Line:

L

hfHGLofslope

fh

L

level to which water will rise

How high will the water rise?


12/36

Darcy-Weisbach Formula

Energy loss due to _______ resistance to

flow

f = friction factor [dimensionless]

L = length of pipe [L]D = diameter of pipe [L]

g= acceleration due to gravity [L/T2]

V= average velocity of water in pipe [L/T]

hf= loss of head [L]

2

f2

f

L Vh

D g

viscous

2

f

2f

L Vgh

D

mechanical


13/36

Darcy-Weisbach Equation

(Function of Flow)

2

f2

f

L Vh

D g

2

2 5

8ff

LQh

g D

0.22

2

8f

f

LQD

g h

Darcy-Weisbach

Solve for D

2

4

D

QV


14/36

Darcy-Weisbach Equation:

What About f?

f is a function of (V*D/) ______________

f is a function of pipe ___________

Take Fluid Mechanics (and Hydraulic Engineering)

to learn how to use this equation...

0.22

2

8f

f

LQD

g h

roughness

Reynolds number

D
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0.01

0.1

1E+03 1E+04 1E+05 1E+06 1E+07 1E+08R

frictionf

actor

laminar

0.05

0.04

0.03

0.020.015

0.010.0080.006

0.004

0.002

0.0010.0008

0.0004

0.0002

0.0001

0.00005

smooth

f

D

Capillary tube or 24 ft diameter tunnelWhere is temperature?Where do you specify the fluid?

Frictional Losses in Straight Pipes

Moody Diagram

0.0112


16/36

Swamee-Jain pipe size equation

04.02.5

4.9

75.4

225.166.0

ff gh

LQ

gh

LQD

?

m102.6h

m/s9.8g

m70,500L

/sm39Q

/sm1.007x10

f

2

3

26

Do the units work? _________Yes!

Moody + Darcy Weisbach =Swamee-Jain0.01

1 E +0 3 1 E +0 4 1 E +0 5 1 E +0 6 1 E +0 7 1 E +0 8R

frictionf

actor

laminar

0.05

0.04

0.03

0.02

0.015

0.010.008

0.006

0.004

0.002

0.0010.0008

0.0004

0.0002

0.0001

0.00005

smooth

ff

D

D

2

f2

f

L Vh

D g

04.02.5

4.9

75.4

225.1

66.0

ff gh

LQ

gh

LQD


17/36

Pipe Roughness

pipe material pipe roughness (mm)glass, drawn brass, copper 0.0015

commercial steel or wrought iron 0.045

asphalted cast iron 0.12

galvanized iron 0.15

cast iron 0.26

concrete 0.18-0.6rivet steel 0.9-9.0

corrugated metal 45.0

Watch these units!


18/36

Delaware Tunnel Diameter

viscosity 1.01E-06

Q 39

L 70500

hf 102.6roughness 0.0006

g 9.8

D 4.12

m2/s

m3/s

m

m

m

m/s2

m

The actual diameter!

04.02.5

4.9

75.4

225.166.0

ff gh

LQ

gh

LQD

Which term

dominates?


19/36

Swamee-Jain Head Loss

Equation

Darcy-Weisbach equation

2

2 5

8

ffLQ

h g D

2

0.9

0.25f

5.74log3.7D R

VDR

Swamee-Jain equation for f

Reynolds number

Calculate head loss given a new flow

Energy loss measured as lost potential energ


20/36

Tunnel Explorations

How long does it take water to get from Rondoutto West Branch (70.5 km)?

What is the Reynolds number?

What happens to head loss in the tunnel if the flowrate is decreased?

D m4 12.

2

213.334

DA m

V QAm s

mm s 391333

2 93

3

2/.. / t L

Vm

m shr 70 500

2 936 7,

. /.

VD

22

2 5

8f

f

LQh Q

g D Where does excess PE go?

2 93 4 12

1 10

12 106 2

6. / .

/

m s m

m s

6 21 10 /x m s-=

0.01

1E+03 1E+04 1E+05 1E+06 1E+07 1E+08R

frictionf

actor

laminar

0.05

0.04

0.03

0.02

0.015

0.010.0080.006

0.004

0.002

0.0010.0008

0.0004

0.0002

0.0001

0.00005

smooth

ff

D

D
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21/36

Solve the tunnel size using

Moody?

0.01

1E+03 1E+04 1E+05 1E+06 1E+07 1E+08R

friction

factor

laminar

0.05

0.04

0.03

0.02

0.015

0.010.0080.006

0.004

0.002

0.0010.0008

0.0004

0.0002

0.0001

0.00005

smooth

ff

D

D

612 10R =

0.0006 0.000154.12

mD me

= =

f 0.0112

0.22

2

8f

f

LQD

g h

0.01

1E+03 1E+04 1E+05 1E+06 1E+07 1E+08R

f

riction

factor

laminar

0.05

0.04

0.03

0.02

0.015

0.010.008

0.006

0.004

0.002

0.0010.0008

0.0004

0.0002

0.0001

0.00005

smooth

ff

D

D


22/36

Summary

Catskill and Delaware water is transported

to NYC without use of pumps

We can calculate the size of a tunnel basedon the required flow rate

The diameter of the tunnel, surface

roughness, length, and elevation dropdetermine the maximum flow rate


23/36

What is a mgd?

Million Gallons per Day

43.8L/ssec86,400

day1

gallon1

L3.7854

day

gallons1,000,000


24/36

Swamee-Jain Excel Equation

=0.66*('roughness'^1.25*('L'*'Q'*'Q'/g/'hf')^4.75

+'viscosity'*'Q'^9.4*('L'/g/'hf')^5.2)^0.04

04.02.5

4.9

75.4

225.166.0

ff gh

LQ

gh

LQD


25/36

Construction of

Cut-and-cover

Aqueduct

Shows steel form and

carriage; also locomotive

crane used to place

concrete, move outside

forms, and assist in

excavation. (White p.220)


26/36

Electric

carriage formoving

interior forms

Carriage and upper jacks

are motor driven. Side

jacks and turntable handdriven. (White p. 221)

T li A d t


27/36

Traveling Aqueduct

Building Plant

Traveling crushing concrete, mixing, and form-moving plant

completing last section of aqueduct adjoining shaft 1 of contract 12.

This plant built 7500 feet of aqueduct in two seasons. (White p. 223)


28/36

Cut-and-cover Arch

This section was

cast between steel

forms with steel plate in

expansion joints at 60-ftintervals. Steel plates 6 x

3/8 were places in both

invert and arch joints to act

as water stops. (White p.

236)

St l F d L ti C


29/36

Steel Forms and Locomotive Crane

Continuous method was here used, forms being used telescoping.

60- to 75-foot section concreted daily. (White p. 374)


30/36

Cut-and-cover

Aqueduct on

Curve

Arch cast with aid of

steel forms built

wedge-shaped in 5-

foot lengths to 200

feet radius. Section

17 feet high by 17

feet 6 inches wide.(White p. 237)

Peak Tunnel


31/36

Peak Tunnel

(Grade Tunnel)

Ready forConcrete Lining

Footing courses are inplace. Center track for

hauling material to upper

portion of contract 11.

Tunnel is 3450 feet longon tangent.(White p. 243)

Completed Press re T nnel Lining


32/36

Completed Pressure Tunnel Lining

Note smooth finish and close joints at invert and springing line.

Concrete surface very dry. (White p. 331)


33/36

Hunters Brook

Steel Pipe

Siphon

Laying of steel pipe on

concrete pedestal blocks.

Later pipe was filled with

water, covered with

concrete and earth and

lined with 2 ins. of mortar.

(White p. 467)


34/36

Hudson River Crossing


35/36

Section/Homework Comments

How can you meter the alum into your

filtration plant? (remember the peristaltic

pump limitations)What range of alum dosage should you be

able to provide?

What happened to the stream flow belowthe reservoir in 1978?


36/36

Stream flow below reservoirMean Daily Streamflow

0.01

0.1

1

10

100

1000

1/1/1942

1/1/1944

1/1/1946

1/1/1948

1/1/1950

1/1/1952

1/1/1954

1/1/1956

1/1/1958

1/1/1960

1/1/1962

1/1/1964

1/1/1966

1/1/1968

1/1/1970

1/1/1972

1/1/1974

1/1/1976

1/1/1978

1/1/1980

1/1/1982

1/1/1984

1/1/1986

1/1/1988

1/1/1990

Date

Flow

Rate(m3/s)

Why does low flow rate appear to have regular pattern?

Note frequency of flows over 10 m3/s What causes flows over 10 m3/s?

Why did low flow rate increase in 1978?

Which season are the higher controlled flows in?

How do you explain occasional low flows after 1978?

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06 Aqueducts