hazen value determination

8/11/2019 Hazen Value Determination

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CONTENTS

1. INTRODUCTION................................................................................................................................1

2. SYSTEM CHARACTERISTIC AND PUMP DUTY POINT..........................................................1

3. DATA ACQUISITION........................................................................................................................3

4. HAZEN WILLIAM C VALUE AND PUMP DUTY POINT ........................................................3

4.1. DANGI PUMPING SYSTEM..............................................................................................................4

4.2. PASIR BESARRAW WATER PUMPING SYSTEM ............................................................................6

4.3. SILANG PUMPING SYSTEM ............................................................................................................8

4.4. PALONG PUMPING SYSTEM .........................................................................................................10

5. CONCLUSION ..................................................................................................................................12

List of Graphs

Graph 1: - Dangi Pressure VS Flow1.85

............................................................................... 4

Graph 2: - System Characteristic Curve for Dangi Pump................................................... 5

Graph 3: - Intake Pressure VS Flow1.85

............................................................................... 6

Graph 4: - System Characteristic Curve for Intake Pump .................................................. 7

Graph 5: - Sialang Pressure VS Flow1.85

............................................................................. 8

Graph 6: - System Characteristic Curve for Sialang Pump ................................................ 9

Graph 7: - Palong Pressure VS Flow1.85

........................................................................... 10

Graph 6: - System Characteristic Curve for Palong Pump ............................................... 11


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List of Tables

Table 1: - Sources of Design data ..................................................................................... 12

Table 2: - Summaries of Pumps Duty Point and Target Flow......................................... 12

Appendix A: -Dangi Pumping System

Pipe Profile by GPS tracking A-i

Data for C value computations A-ii

Photos A-iii

Appendix B: -Intake Pumping System



Photos A-iii

Appendix C: -Sialang Pumping System



Photos A-iii

Appendix D: -Palong Pumping System



Photos A-iii


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1

1.

Introduction

New pumps are proposed to be installed to replace the existing old pumps. To ensure that

the required design flows can be achieved with the new pumps, the existing systems

characteristic need to be established. The parameters required to confirm system charac-

teristic are the pipeline parameters, pump characteristic curves and static lifts. Therefore,

this report shall investigate the availability of existing data and carry out necessary tests,

if necessary, to collect the missing data to establish the system characteristic curve to

confirm the achievable duty flows from the proposed new pumps.

2. System Characteristic and Pump Duty Point

The duty points on any pump are the flow rate against the total head along the designated

pump curves. Therefore pump curves are needed to determine the duty point. The duty

flow rate is the flow that is pushed through the conveying pipes from start end to delivery

end, against the total head, which is the sum of static lift and the friction loss in the con-

veying pipes. Therefore, the system characteristic parameters are required to determine

the duty point on a pump curve. The system characteristic is a function of various pa-

rameters as described below:

a) Pipe size the size of pipe or pipes if there are many different sizes involved

b) Pipe length the length of the pipeline from pump end to receiving reservoirs.

c) Pipe friction factor using Hazen William formula, this factor is termed as C.

d) Static head the different in water levels between suction and delivery.

The pipe frictional head loss is given by Hazen William formula as:

87.485.1

85.1

*

**67.10

dC

QLHl -----------------------------(1)

Where,

L length of pipe in m

Q Flow rate in m3/sec


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2

d Pipe diameter in m

C Hazen William friction factor

Pump total head (Ht) is the sum of static head (Hs) plus pipe friction head loss (Hl), as

shown below:

slt HHH

or

st HdC

QLH

87.485.1

85.1

*

**67.10-------------------------(2)

Let87.485.1 *

*67.10

dC

LK

st HQKH 85.1* ---------------------------------(3)

Which is in the form of y= mx + c

Therefore, the plot ofHtagainst Q1.85will be a straight line, where the y-intercept will be

the static headHs, and with gradient K. The Hazen William C can be calculated as shown

below.

85.187.4*

*67.10dK

LC -------------------------------------(4)

Hence, the valve of C will depend on L length of pipe and d diameter of the pipe. If

the pumping main have mix of pipe sizes in parallel and/or series, the actual C valve of

each pipe cannot be determined. But the duty point still can be determined base on sys-

tem characteristic equation (3), with K as the combined pipe characteristic, provided the

field measurements are accurate.


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3

3.

Data Acquisition

In Section 2 above, to obtain the C valve, the flow against the pressure readings at the

pipes are required (at least 3 point to confirm the set is straight line). The flow and pres-

sure reading will be taken from pumping system with calibrated flow and pressure meas-

urement equipment. For the pumping system without any or all the flow and pressure

measurement equipment, then new equipment shall used to take the readings.

For the pumping system without flow meter to measure the flow rate, externally mount

on flow meter will be used to measure the flow in the pipe. A good location and condition

of the exposed pipe are necessary for attaching the external flow meter to read accurately.

For pumping system without pressure meter, digital pressure meter shall be used to read

the pumping head. Provided an existing tapings on the pipe are available for attaching the

pressure meter.

Having collected the flow and pressure reading for a pumping system, verification on the

correctness of the data collected is necessary. From equation (3), the static head (Hs) can

be obtained from the graph of total head (Ht) against flow1.85

. This static head (Hs) can be

verified, if the level of suction tank and receiving reservoir are known.

4.

Hazen William C value and Pump Duty Point

The size and length of the pumping main is necessary to calculate the C value for the

flow and pressure reading obtained. Therefore, as-built drawings of the pumping main are

necessary. In the event that the as-built drawings are not available, field collection of

these data will be necessary. The pipe length and profile can be estimated using GPS

tracking, and the pipe size will be determined by site measurement on exposed pipe, or be

informed by the operators.


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4

4.1. Dangi Pumping System

As-built drawings on the pipelines are not available, and GPS tracking is used to deter-

mine the length of the pumping main. The plot of the pipeline profile, using GPS tracking

is shown in Appendix A-1, and the length of the pipe is 2300m. The pipe size is obtainedfrom the sign board displayed at the entrance to the WTP, and it is shown as twin 380mm

diameter MS pipe.

The flow reading were taken form the flow meter in the control room, and the pressure

readings were taken using digital pressure meter connected to a tapping at the surge ves-

sel. The analysis of the flow-pressure readings and the graph of pressure against flow1.85

is plotted in Graph 1.

Graph 1: - Dangi Pressure VS Flow1.85

Nine (9) reading are taken and the plot shows a good straight line with correlation of

0.9988. The y-intercept, which is the static head, is 78.1m. The reservoir levels are TWL

Static head = 78.094 m (y-intercept)

Gradient K = 843.67 (Gradient)

C = (10.67*2300.00/ 843.67/0.38^4.87)^(1/1.85)

= 78.96

PLOT of Q^1.85 VS H

y = 707.29x + 78.094

R2= 0.9988

70.000

72.000

74.000

76.000

78.000

80.000

82.000

84.000

86.000

88.000

0.000 0.002 0.004 0.006 0.008 0.010 0.012

Q^1.85

H,m


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5

Pumping System Characteristic Curve

0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 50 100 150 200 250 300

Flow rate in l/sec.

H

eadinm

4 pumps

System curve

with min. lift

C=140

System curve

with max. liftC=78.96

pump duty pointat max. head

pumps Duty point

at min. head

189 232

= 158.5m and BWL = 152.4m as shown on a sign board at the reservoirs gate. The suc-

tion tank does not have any recorded levels, but site survey plan has indicated the ground

level is around 77m. The suction tank TWL and BWL are assumed to be 79m and 76m

respectively. Therefore, the static head calculated is between 79.5m to 82.5m, which is

close to the computed value. Hence, the static head obtained from the test is acceptable.The calculated C value is 78.96, assuming the pipe is twin 380mm in diameter and

2300m long, without any branched pipes.

Based on the data collected, the system curves are plotted on the pump curves as shown

in Graph 2, to determine the duty points. The suction pipeworks from suction tank to the

pumps are buried, and detail record drawings are not available, hence, the station loss

cannot be calculated and is assumed to be 2m.

Graph 2: - System Characteristic Curve for Dangi Pump

The minimum duty flow rate is 189 l/s (=680 m3/hr) when four (4) new pumps are run-

ning. The flow will increased to 232 l/s (=835 m3/hr), if the pipes are replaced with new

pipe. The target flow, with 4 pump running is 555 m3/hr; as indicated in drg.

PAAB/NOO9-3/BWP-MIO-DG/PS/M/5001, which is less that the minimum flow of 680

m3/hr, Hence, the selected pumps is able to delivery the target flow.


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C = (10.67*270.00/ 149.34/0.40^4.87)^(1/1.85)

= 55.25

PLOT of Q^1.85 VS H

y = 149.34x + 45.393

R2= 0.9926

50.500

51.000

51.500

52.000

52.500

53.000

53.500

54.000

54.500

0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070

Q^1.85

H,m

4.2. Pasir Besar Raw Water Pumping System



is shown in Appendix B-1, and the length of the pipe is 270m. The pipe size, as told bythe operator, is 400mm diameter MS pipe.

There is no existing flow measurement at site and suitable location to attach the flow me-

ter cannot be found around the intake. Therefore, the flow measurement was taken at the

aerator by attaching the flow sensors to the vertical aerator pipe. The pressure readings

were taken using digital pressure meter connected to a tapping at the surge vessel. The

analysis of the flow pressure readings and the graph of pressure against flow1.85

is plotted

in Graph 3.

Graph 3: - Intake Pressure VS Flow1.85

A total three (3) reading were registered and the plot shows a straight line with correla-

tion 0.9928. The y-intercept, which is the static head, is 45.4m. There is no record for

river maximum and minimum levels, and also the level at aerator outlet are not available


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as well. Therefore, based on the site survey plan and observation by the operators, the

maximum and minimum river water levels are assumed to be 30m and 22m respectively.

The aerator outlet also assumed to be 45.0m, based on ground survey plan of the WTP.

The static head calculated is between 23m to 15m, which do not agree with the static

head computed based on field test reading. A second field test was conducted on 4

th

, Dec.2012, and the operator has in deed confirmed that the surge vessel at the intake is for the

old intake (ABJV) and hence the pressure readings taken in previous is not the pressure

represent the new intake pump. There is not tapping on the existing pipe and hence, sec-

ond round of test to take the pressure reading is not possible. This confirmed that the

pressure readings taken are not valid.

Since the tests for C value of the raw water pipe is not successful, the investigation of

pump duty point was carried out based on common engineering practice. The pipe lengthof 270m as indicated by GPS tracking is taken as correct. Assuming that the old raw wa-

ter pipe is 400mm diameter MS pipe; with C value of 90, and it is generally agreed that

any pipe with C value less than 90 is not cost effective to continue using, because of

the high energy loss from frictional losses. In addition, the suction pipeworks from river

to the intake are buried, and detail no record drawings are not available. Therefore actual

station losses cannot be calculated and station loss is assumed to be 2m. The system

curves are plotted on the pump curves as shown in Graph 4, and the duty point is 272 l/s

(=979 m3/hr), which is more than the target duty point of 227 l/s (=818 m

3/hr).

Graph 4: - System Characteristic Curve for Intake Pump


0.00

20.00

40.00

60.00

80.00

100.00

0 50 100 150 200 2 50 3 00 3 50 4 00

Flow rate in l/sec.

Headinm

1 pumps

System curve

with min. lift

C=120

System curve

with max. lift

C=90

pump duty pointat max. head

pumps Duty point

at min. head

313

INTAKE SYSTEM

272


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4.3.

Silang Pumping System



is shown in Appendix C-1, and the length of the pipe is 3700m. The operator informed

that the pipe size is 250mm in diameter.

There is no existing flow measurement at site and flow measurements were recorded by

attaching the flowmeter to exposed manifold outside the pumping station. The pressure

readings were taken using digital pressure meter connected to a tapping at the surge ves-

sel. The analysis of the flow pressure readings and the graph of pressure against flow1.85


Graph 5: - Sialang Pressure VS Flow1.85

Nine (9) reading are taken and the plot shows a good straight line with correlation of

0.9982. The y-intercept, which is the static head, is 73.4m. The reservoir levels are TWL

= 112.77m and BWL = 108.5m as shown on a sign board at the reservoirs gate. The suc-



C = (10.67*3700.00/ 5928.6/0.25^4.87)^(1/1.85)

= 107.14

PLOT of Q^1.85 VS H

y = 5928.6x + 73.448

R2= 0.9962

74.000

76.000

78.000

80.000

82.000

84.000

86.000

0.000 0.001 0.001 0.002 0.002

Q^1.85

H,m


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tion tank does not have any recorded levels, but site survey plan has indicated the ground

level is around 36m. The suction tank TWL and BWL are assumed to be 35m and 37m

respectively. Therefore, the static head calculated is between 75.77m to 77.77m. Hence,

the static head obtained from the test is acceptable. The calculated C value is 107.14,

assuming the pipe is 250mm in diameter and 3700m long, without any branched pipes.

Based on the data collected, the system curves are plotted on the pump curves as shown

in Graph 6, to determine the duty points. The suction pipeworks from suction tank to the

pumps are buried, and detail no record drawings are not available, hence the station loss

cannot be calculated and is assumed to be 2m.

Graph 6: - System Characteristic Curve for Sialang Pump

The minimum flow rate is 34 l/s (=122 m3/hr) when solo pump is running. The flow will

increased to 43 l/s (=155 m3/hr), if the pipes are replaced with new pipe. The target flow,

for solo pump running is 160m3/hr; 24% short off the target flow. Hence, the selected

pump is unable to delivery the target flow.


0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 10 20 30 40 50 60

Flow rate in l/sec.

Headinm

1 pumps

System curve

with min. lift

C=140

System curve

with max. lift

C=107.1

pump duty point

at max. head

pumps Duty point

at min. head

34 43

Sialang System


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4.4. Palong Pumping System



is shown in Appendix D-1, and the length of the pipe is 10,000m. The operator informedthat the pipe size is 380mm in diameter.

There is no existing flow measurement at site and the manifolds are buried under ground

outside the pumping station. Similarly, there are no suitable tapings on any of the ex-

posed pipe for measuring of pressures. Therefore, both the flow and pressure measure-

ments are taken at the exposed pipe crossing outside the WTP. The analysis of the flow

pressure readings and the graph of pressure against flow1.85


Graph 7: - Palong Pressure VS Flow1.85

Four (4) reading are taken and the plot shows a good straight line with correlation of

0.9961. The y-intercept, which is the static head, is 35.7m. There were neither record

drawings of Palong reservoir nor any sign board at the gate showing the TWL and BWL

of the reservoir. Hence, the TWL and BWL of Palong reservoir are estimated using GSP


Gradient K = 1844 (Gradient)

C = (10.67*10000.00/ 1844/0.38^4.87)^(1/1.85)

= 114.51

PLOT of Q^1.85 VS H

y = 1844.9x + 35.698

R2= 0.9961

62.000

64.000

66.000

68.000

70.000

72.000

74.000

0.000 0.005 0.010 0.015 0.020 0.025

Q^1.85

H,m


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11

tracking as 101m and 96m respectively. Similarly, the suction tank does not have any re-

corded levels, but site survey plan has indicated the ground level is around 36m. The suc-

tion tank TWL and BWL are assumed to be 35m and 37m respectively. Therefore, the

static head calculated is between 64m to 66m, which is almost twice that obtained from

site measurements. Therefore, this confirmed that the readings taken are not valid.

A second field test was conducted on 4th

, Dec. 2012, to repeat the test again, but the sec-

ond test recorded the pumping head was only 40+m only, which is lower than the previ-

ous test of 70+m. Therefore, the system characteristic curve cannot be determined.

Since the tests for C value of the pipe is not successful, the investigation of pump duty

point was carried out based on common engineering practice. The pipe length of 10,000m

as indicated by GPS tracking is taken as correct. Assuming that the old pumping main is

250mm diameter MS pipe; with C value of 90. It is generally agreed that any pipe with

C value less than 90 is not cost effective to continue using, because of the high energy

loss from frictional losses. In addition, the suction pipeworks from the suction tank to the

pumping station are buried, and detail no record drawings are not available. Therefore

actual station losses cannot be calculated and station loss is assumed to be 2m. The sys-

tem curves are plotted on the pump curves as shown in Graph 8, and the duty point is 80

l/s (=288 m3/hr), which is more than the target duty point of 72 l/s (=260 m

3/hr).

Graph 8: - System Characteristic Curve for Palong Pump


0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 30 60 90 120

Flow rate in l/sec.

Headinm

1 pumps

System curve

with min. lift

C=140

System curve

with max. lift

C=90

pump duty point

at max. head

pumps Duty point

at min. head

80 96

Palong System


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5. Conclusion

Ideally, all the data for estimation of pump duty flows should be available from record

drawings or inventory database. But almost non are available, and these data are obtained

by means of estimation or through mouth of experience operators. Therefore, the accu-

racy of the computed duty points are compromised. Table 1 below summarized the

source of data used in this report.

Table 1: - Sources of Design data

Out of the four (4) pumping system investigated, only one (1), Sialang pumping system,

is not able to achieve the target flow. Table 2 below tabulated the computed duty flows

and the targeted flow for all the four (4) pumping systems.

Table 2: - Summaries of Pumps Duty Point and Target Flow

Pumping

System

Pipe length,

m

Pipe size,

mm Reservoir Levels, m Suction Tank Levels, m

2300 380dia. X2 158/152 76/ 79

GPS Operator Sign Board Ground Survey plan

270 400 45 (areator) 22 / 30 (river)

GPS Operator Ground Survey plan Ground Survey plan

3700 250 112/ 108.5 35/37GPS Operator Sign Board Ground Survey plan

10000 380 101/96 35/37

GPS Operator GPS Ground Survey plan

Dangi

Intake

Sialang

Palong

Pumping

System

Duty flow,

m3/hr

Target flow,

m3/hr Diff. (%)Dangi 680 555 123%

Intake 979 818 120%

Sialang 122 160 76%

Palong 288 260 111%


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Appendix A: -Dangi Pumping System


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Dangi Pipe 'C' Value Computation:

Pipe size = 0.38 mPipe length = 2300.00 m

Q, cum/hr Q, (1 pipe) P, bars Q, cum/s Q.

H,m

545.0 272.5 8.689 0.0833 0.010 85.283

538.0 269.0 8.676 0.0822 0.010 85.155

530.0 265.0 8.65 0.0810 0.010 84.900

428.0 214.0 8.41 0.0654 0.006 82.544

423.0 211.5 8.4 0.0646 0.006 82.446

414.0 207.0 8.376 0.0633 0.006 82.210

138.4 69.2 8.022 0.0211 0.001 78.736

137.1 68.6 8.017 0.0209 0.001 78.687134.0 67.0 8.014 0.0205 0.001 78.657



C = (10.67*2300.00/ 843.67/0.38^4.87)^(1/1.85)

= 78.96

Measured Computed

PLOT of Q^1.85 VS H

y = 707.29x + 78.094

R2= 0.9988

70.000

72.000

74.000

76.000

78.000

80.000

82.000

84.000

86.000

88.000

0.000 0.002 0.004 0.006 0.008 0.010 0.012

Q^1.85

H

,m


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Dangi Suction Tank

Dangi Reservoir


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Appendix B: -Intake Pumping System


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Pasirt Besar Raw Water Pipe 'C' Value Computation:

Pipe size = 0.40 m, area = 0.13 sq.mPipe length = 270.00 m

Measured Computed

Q, cum/hr Q, (1 pipe) P, bars Q, cum/s Q1.85

H,m V, m/s

768.0 768.0 5.51 0.2133 0.057 54.081 1.70

746.0 746.0 5.438 0.2072 0.054 53.374 1.65

619.0 619.0 5.213 0.1719 0.039 51.166 1.37



C = (10.67*270.00/ 149.34/0.40^4.87)^(1/1.85)

= 55.25

PLOT of Q^1.85 VS H

y = 149.34x + 45.393

R2= 0.9926

50.500

51.000

51.500

52.000

52.500

53.000

53.500

54.000

54.500

0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070

Q^1.85

H,m


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Intake

Aerator


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Appendix C: - Sialang Pumping System


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C


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C

Sialang Pipe 'C' Value Computation:

Pipe size = 0.25 mPipe length = 3700.00 m

Measured Computed


H,m

119 119.0 8.571 0.0331 0.002 84.124

116.8 116.8 8.578 0.0324 0.002 84.193

119.7 119.7 8.574 0.0333 0.002 84.154

65.82 65.8 7.819 0.0183 0.001 76.743

64.48 64.5 7.817 0.0179 0.001 76.724

34.95 35.0 7.615 0.0097 0.000 74.741

86.32 86.3 8.096 0.0240 0.001 79.462

83.89 83.9 8.08 0.0233 0.001 79.30583.53 83.5 8.068 0.0232 0.001 79.187



C = (10.67*3700.00/ 5928.6/0.25^4.87)^(1/1.85)

= 107.14

PLOT of Q^1.85 VS H

y = 5928.6x + 73.448

R2= 0.9962

74.000

76.000

78.000

80.000

82.000

84.000

86.000

0.000 0.001 0.001 0.002 0.002

Q^1.85

H,m


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C

Sialang Suction Tank

Sialang Reservoir


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Appendix D: - Palong Pumping System


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D


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D

Palong Pipe 'C' Value Computation:

Pipe size = 0.38 m

Pipe length = 10000.00 m

Measured Computed


H,m

430.5 430.5 7.3 0.1196 0.020 71.650

423.3 423.3 7.25 0.1176 0.019 71.159

420.2 420.2 7.18 0.1167 0.019 70.472

368.2 368.2 6.4 0.1023 0.015 62.816

Static head = 35.698 m (y-intercept)Gradient K = 1844 (Gradient)

C = (10.67*10000.00/ 1844/0.38^4.87)^(1/1.85)

= 114.51

PLOT of Q^1.85 VS H

y = 1844.9x + 35.698

R2= 0.9961

62.000

64.000

66.000

68.000

70.000

72.000

74.000

0.000 0.005 0.010 0.015 0.020 0.025

Q^1.85

H,m


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Palong Pumps

Palong Reservoir

hazen value determination

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