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Chapter3

Part 2

The Feasibility Study on Urgent Water Resources Development and Supply for

Kabul Metropolitan Area

3-18 CTI Engineering International Co., Ltd. and

Yachiyo Engineering Co., Ltd.

Sanyu Consultants Inc.

Ta

ble

3.1

.6

Wate

r Q

uali

ty A

naly

sis

Res

ult

in

Pan

jsh

r F

an

Are

a (

Sec

on

d A

naly

sis

in 2

011

; N

ov.

– D

ec.)

R1

R2

R3

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Q2

Q3

Q4

Q5

Q6

Q7

Q8

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S1

BS

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2JS

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1T

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JM1

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6Q

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MK

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SW

5

Sam

plig

Dat

e11

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12/2

812

/28

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011

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11/1

011

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11/2

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11/2

811

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11/1

112

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411

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12/2

812

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01/

410

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11/1

112

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411

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010

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8

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ener

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Tem

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312

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.3

Ele

ctri

c

cond

uctiv

ity

μS

/cm

at

25℃

420

610

480

670

500

430

380

740

710

690

700

710

730

690

640

720

710

720

680

840

760

760

710

820

700

910

680

560

730

690

(<1,

900

μS　

/cm

≒T

DS

1,20

0mg

/l)

pH8.

47.

98.

07.

97.

98.

07.

98.

18.

18.

17.

87.

37.

47.

47.

37.

27.

47.

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5(5

)

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65

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63

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65

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35

55

56

56

45

55

0

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n C

onta

min

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CO

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g/l

55

05

56

55

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55

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55

55

55

55

55

6

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g/l

15

31

01

22

13

13

54

31

11

22

23

32

32

11

3-

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mon

iaN

H3

mg/

l as

NH

3-N

0.04

0.03

0.06

0.07

0.08

0.08

0.08

0.08

0.07

0.07

0.07

0.06

0.06

0.06

0.05

0.06

0.06

0.05

0.07

0.02

0.06

0.08

0.01

0.02

0.06

0.06

0.08

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l as

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007

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1 (

sho

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)

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ate

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l as

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3-N

0.40

0.30

1.40

1.30

0.80

1.70

0.70

0.90

0.90

1.30

1.00

0.80

1.30

1.30

1.40

1.10

1.10

1.10

0.30

0.10

1.30

1.40

0.10

0.20

1.40

1.70

0.50

0.10

0.60

1.20

11

.3

<M

ain

Ions

>

Sod

ium

Na+

mg/

l68

6762

110

8781

120

140

140

160

110

110

6874

9089

8368

9311

010

011

094

9810

012

094

8485

80(2

00)

Pot

assi

umK

+m

g/l

11.0

11.0

9.0

9.5

6.0

3.8

4.5

13.0

12.0

11.5

13.0

20.5

10.5

10.0

16.0

23.5

10.0

10.5

11.5

12.5

15.5

11.5

8.0

12.5

9.0

19.0

13.0

14.0

11.0

21.5

Cal

cium

Ca2

+m

g/l

5444

8056

6456

5894

8884

8254

6482

6272

116

8058

8466

8072

8454

6054

7270

64

Mag

nesi

umM

g2+

mg/

l55

4453

102

5863

5743

6166

6081

4962

5549

7390

5556

5058

7280

106

5360

4955

49

Bic

arbo

nate

HC

O3-

mg/

l13

415

228

026

215

917

715

225

026

226

223

221

329

330

521

921

327

437

225

625

021

317

718

925

626

833

517

117

720

121

3

Chl

orid

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3813

343

4350

7365

6573

8835

3865

8550

4370

5068

100

5045

125

8880

6870

90(2

00)

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fate

SO

42-

mg/

l65

7065

9560

4525

110

120

105

9510

011

010

095

110

110

9095

130

100

120

8011

590

135

140

8080

100

(500

)

Har

dnes

sm

g/l a

s

CaC

O3

360

290

420

560

400

400

380

410

470

480

450

470

360

460

380

380

590

570

370

440

370

440

475

540

570

370

380

380

400

360

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ther

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Man

gane

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010.

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100.

010.

010.

000.

000.

000.

000.

000.

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000.

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010.

000.

010.

000.

010.

000.

000.

000.

010

.4

Iron

(to

tal)

Fe2

- ,Fe3

-m

g/l

0.03

0.03

0.05

0.18

0.10

0.13

0.03

0.07

0.04

0.09

0.10

0.05

0.03

0.04

0.03

0.04

0.07

0.04

0.01

0.10

0.03

0.01

0.05

0.12

0.26

0.02

0.00

0.07

0.01

0.04

(0.3

)

Flu

orid

eF

-m

g/l

0.27

0.78

0.17

0.21

0.28

0.14

0.31

0.57

0.62

0.34

0.52

0.06

0.14

0.30

0.07

0.21

0.24

0.17

0.29

0.64

0.08

0.28

0.41

0.18

0.20

0.29

0.13

0.26

0.18

0.18

1.5

Ars

enic

(Tot

al)

As3

+,A

s5+

mg/

l0.

000

0.00

00.

000

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00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

0.00

00.

000

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00.

000

0.00

00.

000

0.00

00

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<M

icro

bial

>

Tot

al

Col

ifor

m 1

CF

U/m

l20

2980

4338

2525

8080

8080

203

203

200

045

040

501

570

3510

016

102

Tot

al

Col

ifor

m 2

CF

U/m

l5

2870

6040

3040

100

100

100

100

4010

010

03

4015

010

00

511

033

015

3830

53

E.

Col

iC

FU

/ml

00

00

00

00

00

00

00

00

00

00

00

00

00

00

00

Gen

eral

bact

eria

CF

U/m

l38

5545

4135

3823

100

100

100

100

1110

10

50

057

00

608

036

011

160

103

10

Not

e: 1

) T

he it

alic

val

ue m

ay b

e do

ught

ful,

judg

ed f

rom

app

eara

nce

and

exis

ting

resu

lts.

2) S

hade

d va

lue

show

s on

e be

yond

the

WH

O g

uide

line.

3)

Ana

lysi

s m

etho

d of

Man

gane

se h

as b

een

chan

ged

to a

pro

per

one.

4)

Ion

bala

nce

of m

ain

ions

to

be im

prov

ed.

WH

O D

rin

kin

g W

ater

Gu

ideli

ne /

(rec

om

men

ded

val

ue)

Item

Uni

t

Riv

erC

anal

Spr

ing

Wel

l



Chapter3

Part 2

CTI Engineering International Co., Ltd. and



3-19

Table 3.1.7 Result of Water Quality Analysis in Japan

on Heavy Metals

Table 3.1.8 Result of Water Quality Analysis on Panjshir River Water

at Sayad by USGS & AGS

(c) Turbidy of Water

Tubidity of Ghorband River water becomes extremely high in wet season showing brown color as

seen in Figure 3.1.21 and ranging 100 FTU to more than 1,000 FTU (Apr. to May 2012), whereas

the water is transparent in dry season showing 1 FTU to 12 FTU (Jan. 2012).

Water

Teper-

ature

EC ｐH Cd Pb Cr6+ As

Hg,

totalSe Mn

(℃) (mS/m) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l)

R2 7/9/11 23.3 0.43 8.5 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

IG1 7/9/11 18.0 0.68 7.9 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

Q1 7/9/11 17.4 0.82 7.7 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

Q2 7/9/11 18.9 0.68 8.0 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

Q4 7/9/11 14.8 0.47 7.7 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

Q8 7/1/11 19.6 0.84 7.7 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

JE1 7/11/11 14.8 0.80 7.5 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

JS1 7/9/11 13.8 0.85 7.5 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

TW1 7/9/11 15.3 0.92 7.5 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

TW2 7/9/11 13.0 0.88 7.2 <0.001 <0.005 <0.01 <0.005 <0.0005 <0.002 <0.01

Note: Temperature, EC and pH are measured on sampling.

Other itmes are meashured in Japan with ICP mass analyzer/ICP emission spectrometer or Atomic absorption spectrometer.

Canal

Well

Site No.Kind of

Water

Sampling

Date

River

No.

Sampling

Date

(month-

day-year)

Water

temper-

ature

(°C)

Spec.

cond.

(μ

S/cm)

pH

in

field

Total coli

count per

100 mL

E. coli

count

per 100

mL

NO3 as

NO3

(mg/L)

Ca

(mg/L)

Mg

(mg/L)

Na

(mg/L)

K

(mg/L)

Alka-

linity

mg/L as

HCO3

Cl

(mg/L)

SO4

(mg/L)

1 12-09-06 9.5 401 8.50 649 70

2 12-26-06 11.4 427 8.44

3 01-09-07 9.1 424 8.40

4 01-23-07 9.4 442 8.52

5 02-06-07 12.5 448 8.44 4.59 50.6 12.5 20 5.3 189.5 33.7 28.3

6 02-20-07 10.5 343 8.37 435 98.5 4.89 53.2 13.8 22.8 5.7 197.6 37.5 31.6

7 03-06-07 12.7 474 8.37 4.55 51.9 14.1 22.3 5.7 176 35.4 32.7

8 03-20-07 8.9 262 8.51 5.99 33 6.82 8.94 3.5 113 15.2 18.8

9 04-03-07 11.2 232 8.17 5.95 29.5 5.45 6.64 3.3 100 11.4 17

10 04-17-07 12.3 275 8.65 5.32 32 8.09 9.14 3.6 124.7 11.7 20.2

11 06-19-07 14.8 261 8.52 3.14 29.3 7.37 10.4 3.3 112.6 14.1 22.1

0 0 50WHO Gudeline

No.

Sampling

Date

(month-

day-year)

F

(mg/L)

As

(μg/L)

Ba

(μg/L)

B

(μg/L)

Cd

(μg/L)

Cr

(μg/L)

Cu

(μg/L)

Pb

(μg/L)

Mn

(μg/L)

Mo

(μg/L)

Ni

(μg/L)

Se

(μg/L)

U

(μg/L)

5 02-06-07 0.05 1.2 41 320 <0.05 <1 0.5 0.24 4 0.6 1.2 <1 2.27

6 02-20-07 0.06 1.1 44 380 <0.05 <1 0.1 <0.05 4 0.7 1.2 <1 2.37

7 03-06-07 0.08 1 40 400 <0.05 <1 0.1 0.29 4 0.6 1.1 <1 1.94

8 03-20-07 0.09 1.8 25 60 <0.05 <1 0.2 <0.05 5 0.9 1 <1 1.59

9 04-03-07 0.08 1.6 23 40 <0.05 <1 0.3 <0.05 6 1.1 1 <1 1.42

10 04-17-07 0.1 1 20 160 <0.05 <1 <0.1 <0.05 9 0.8 1 <1 0.83

11 06-19-07 0.06 0.9 22 200 <0.05 <1 0.7 <0.05 2 0.8 0.5 <1 0.91

1.5 10 700 500 3 50 2000 10 400 70 70 10 15

Note - Source: Mack, T.J., Akbari, M.A. et al. (2009) (http://pubs.usgs.gov/sir/2009/5262/)

"No." attached by the the JICA Study team. The original site no. and location are "312" and "Punjshir River at Sayad".

WHO Gudeline

Chapter3

Part 2






Turbidity of canal water differs at canals. All main canals on Tr-3 and Tr-7 terraces - Bagram,

Parwan, Almatoi and Dam Shag, become brown in water color in wet season. In dry season,

Bagram and Parwan water is clear, whereas Almatoi and Dam Shag have some turbidity maybe

due to mixture of sewage water.

Among the main discharging canals on Tr-1 terrace, Qara So (Q1 point) always have some

turbidity (11-16 FTU in dry season; higher in wet season as shown in Figure 3.1.21). Shakh Ab

Haji Habib (Q4 point) is always clear, showing turbidity 0 -1 FTU. Bada Khaw Bala (Q2 point)

shows intermediate turbidity between Q1 and Q4. Canal Asia (Q8) is clean in dry season, whereas

it shows some turbidity in wet season.

Figure 3.1.21 Turbidity Condition of Ghorbnad River and

Representative Canals in Wet Season

(d) Electric Conductivity of Water

Figure 3.1.22 shows distribution of electric conductivity (EC) of water in the investigation area.

Groundwater and surface water in Tr-7 and Tr-3 terraces show higher EC, ranging 750-1100µS/cm

excluding water of main canals and their branches which show 300 -500µS/cm. In and around

"Nawre Cheshma", water of springs and canals have lower EC ranging 300 -500 µS/cm. Canals

between Tr-3 terrace scarp and "Nawre Cheshma" show intermediate values between the two

areas. Ghorband River water has 500 -600µS/cm in the middle reach of the area and

600 -750µS/cm in the lower reach. The latter may include waters from different origins. In flood

season, it shows around 300µS/cm.

Spring water in the area between the two big rivers and on the left bank of Panjshir River shows

much lower EC than water of most springs in the right bank of Ghorband River.



Chapter3

Part 2




3-21

High EC may imply that water stays longer in aquifer or inflow of sewage water.

Source: Hearing survey in 2009 and 2011, and field survey in 2011 by JST.

Figure 3.1.22 Distribution of Electric Conductivity of Water

(9) Water Use

(a) Panjshir Fan Area

Water use in the

investigation area is

summarized in Table

3.1.9. Water use is closely

related to land use (see

Subsection 2.3.2 and

Figure 3.1.9).

(b) Downstream Area

In the downstream of the

investigation area, main

water use on Panjshir

River is irrigation in the

area shown in Figure

3.1.23 judging from the

satellite image and

topographic map.

Table 3.1.9 Water Use and Water Sources in the

Investigation Area

Note: ○ – main source, △ – secondary source

River

Spring and

Canal (spring

water)

Canal

（surface

water)

Well Dug Pit

Generator and mill ○

Hunting pool ○

Irrigation △ ○ △

Generator and mill △ △

Hunting pool ○ △

Drinking ○

Household and animals △

Tr-3 terrace scarp Generator and mill ○

Irrigation ○ △

Hunting pool △ ○

Drinking ○ ○

Household and animals ○ △ ○

Tr-7 terrace scarp Generator and mill ○

Irrigation ○

Drinking ○

Household and animals △ ○

Water Source

Ghorband River

Tr-1 terrace

Tr-3 terrace

Tr-7 terrace

PurposeArea

Chapter3

Part 2






Figure 3.1.23 Downstream Area where the Panjshir River Water is Used

3.1.3 Water Budget

(1) Movement of Water on Groundwater in the Study Area

Figure 3.1.24 shows a schematic aquifer profile of the investigation area and water budget

components. As shown in Figure 3.1.19, the following two groundwater flows are inferred.

(a) Higher terraces to the river

Recharge may come from precipitation, irrigation water in field and leakage water of canals. A

hunting pool created above groundwater table also could be a recharge source. In residential area,

sewage water might be added into groundwater body.

Runoff of groundwater occurs through well, spring, seepage to discharging canals and discharge to

the river. There are many springs and the water is mainly collected and discharged by Qara So

Canal (Q1), canals of Bada Khaw Bala (Q2 &Q3) and Asia Canal (Q8 &Q9). Evapo-transpiration

may have a small role for runoff of groundwater as found from the observation at TW-1.

(b) Upstream area to "Nawre Cheshma" along the river

Recharge might be made in Ghorband River bed or canals to the upstream of the investigation area.

Water is seeping out in and around "Nawre Cheshma" and mainly collected and discharged by

Shakh Ab Haji Habib (Q4) canal. Some amount of water may be seeping out directly to the

Ghorband riverbed.

Agricultural field in this area

uses Panjshir River water flowing in the downstream of

the water intake area.

This area is an elevated alluvial terrace and water comes from the upper terraces.

Bagram Airport

Sayad

Water Intake Line



Chapter3

Part 2




3-23

Figure 3.1.24 Schematic Profile of Aquifer and Water Budget Components

in the Investigation Area

(2) Components of Water Budget

(a) Groundwater recharge

The average precipitation in and around the investigation area could be assumed to be 350

mm/year, considering the average precipitation at Bagram and Jabul Saraj and distance from them

to the investigation area. According to the master plan report, groundwater recharge rate in flat area

around Kabul is estimated to be around 5% of precipitation, judging from runoff rate of Kabul

River. If the rate is applied to this area, the groundwater recharge is 17.5 mm/year or 48 m3/d/km

2

or 0.00056 m3/s/km

2. If the measured canal discharge in September of 2011, 2.5 m

3/s, is supplied

by precipitation, the recharge area must be 4,464 km2. Considering the area of the whole Panjshir

River Fan is about 280 km2, it is not probable for the precipitation to be a main groundwater

recharge source.

Probable main recharge sources must be irrigation water in field and leakage water from canals. A

dense irrigation network

develops in and around

investigation area which

water is supplied from the

main canals shown in Figure

3.1.8. Most canals have no

lining on the bottom.

Another probable large

recharge source is the

Ghorband River. In the

middle reach of the river,

water flow disappears into

underground. "Nawre

Cheshma" must be mainly

supplied with such river

water.

(b) Groundwater runoff

In dry season, main canals on

Tr-3 and Tr-7 terraces, which water comes from river, are dried up. In such cases, discharging

water of canals on Tr-1 terrace is considered to come all from springs. That is, the water is all

groundwater runoff. The condition in September of 2011 fits the case. Measured total discharge is

around 2.5 m3/s. The measurement is not covered for all canals and some water volume must

Almatoi & Dam Shag Canal

Recharge from Precipitation Recharge from Canal

Parwan Canal Bagram Canal

Runoff through Well

Recharge from Pond

Pool

Pool

Spring

Recharge by Sewage

Ghorband RiverDischarge Canal

Runoff to Spring

Runoff to River

Runoff to Canal

Recharge by Irrigation

Runoff by Evapotranspiration

Runoff to Pool

Older Geavel

Younger Geavel

TR-1 Terrace

TR-3 Terrace

TR-7 TerraceReworked Loess

Slope sediment

Figure 3.1.25 Excess Groundwater Discharge in Early

October, 2011

Dischargemeasurement point on Oct. 3rd.Q= approx. 4 m3/s

Groundwater Discharge through canals 2.5m3/s

Groundwater Discharge to Ghorband River Bed 1.5m3/s +α

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discharge directly to the riverbed. The running water at the test infiltration gallery site (Figure

3.1.25) includes such two kinds of water. The rate was roughly measured to be 4.0 m3/s in the early

October 2011.

According to villagers, 2011 is a kind of drought year, though it is better than 2004 which is

severest in these ten years. Also according to villagers, the discharge is not so different even in

such draught year. A satellite image of 2004 in Figure 3.1.13 may prove such condition, because it

is taken on the smallest discharge day at Shukuhi Hydrologic Station of Panjshir River and the

seeping start point on the Ghorband riverbed looks mostly the same as this year.

According to rainfall data in Jabul Saraj, probability of drought year is 1/6 for 2011 and 1/10 for

2004.

(c) Storage

The aquifer is a natural large storage which could mitigate drought. Therefore, effect of drought on

groundwater appears smaller than on surface water. To know the condition, long term observation

is required.

(3) Water Budget

Detail of water budget is unknown in the investigation area. However, even in dry season of a drought

year with 1/6 probability, more than 2.5 m3/s of excess water is running out of the lowland canals and

more than 4.0 m3/s excess water is running out through Ghorband River as shown in Figure 3.1.25.

3.1.4 Assessment of Items Relevant to Groundwater Development Potential

From the hydro-geological investigation, the basic items relevant to groundwater development potential

are assessed as follows:

Water budget

It is confirmed that more than 4.0 m3/s excess water is running out of the investigation area in a

drought year with 1/6 probability in annual precipitation. This amount is larger than the

development target of 2.39 m3/s (1.01 m

3/s in the 1

st stage), but the proportion of development

amount to the discharge is not small. Therefore, the environmental impact must be considered well

with estimation of discharge in further drought years.

Water quality

Quality of water distributed in the area is basically no problem as the source of drinking water.

Hydraulic ability

The main aquifer in the area, the Younger gravel, has 10-2

to 10-1

cm/s order permeability and 25 to

50m thickness. This corresponds to or exceeds the ability of the Logar Aquifer in Kabul Basin

which is the most promising aquifer in the basin. In addition, the test infiltration gallery proved its

water collection ability (36 liter/s with 1.5m drawdown). Therefore, it is judged that the aquifer has

enough hydraulic ability to develop water.

Environmental impact

The environmental impact by the water development is estimated and assessed in the next chapter

and Chapter 8.

Among the four items, water quality and hydraulic ability are clarified. As for the water budget, it is

confirmed that the target development amount is less than the present discharge from the area in a little

drought year. The developable water volume in severe drought years and environmental impact by the

development are assessed in the next chapter and Chapter 8.



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3-25

3.2 Preliminary Study on Intake Facility

According to the above investigation results, the Panjshir Fan area including the Ghorband River and the

lower terraces Tr-1 and Tr-3 seems suitable as the water intake facility site because of their of thick

permeable gravel layers. On the other hand it should be reminded that these areas are not an empty land

but inhabited and agricultural land. In the selection of the intake facility, social acceptance as well as

engineering matters should be taken into consideration.

Four types of intake facility were conceived as the intake facility for this area. They are 1) Deep Well,

2) Radial Collection Well, 3) Infiltration Gallery, and 4) Intake Weir. Those of 1) to 3) are facilities for

taking groundwater, while 4) is for taking surface water (river water).

Based on the results of the hydro-geological and socio-economic surveys, these four types of intake

facility are preliminarily planned with the total design intake discharge of 2.39 m3/s (corresponding to

52.8 MCM/year) of the Phase-1 and 2 development, and their advantages and disadvantages are

compared for further study on the intake facility.

3.2.1 Preliminary Planning of Four Different Intake Facilities

(1) Deep Well

Deep well is a conventional and orthodox water intake facility for drinking water in Afghanistan. The

lowest terrace Tr-1 seems suitable for the well field because of its thick aquifer, although it is a habitual

flood inundation area. Floods can be avoided if the wells are constructed in the higher terrace Tr-3, but

it will not be accepted by the local people because the existing water uses in the lower terrace will be

affected by the water extraction in the upper terrace.

Figure 3.2.1 Deployment Plan of Deep Wells

Considering the thickness and permeability of the aquifer, water production of about 6,000 m3/day

(0.069 m3/s) per well is expected. Thus, 38 wells in total including three (3) reserve ones are required

to be constructed in the terrace. In order to avoid interference among the wells, they are placed at least

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200 meters away from each other in the 230 ha agricultural and hunting pool area as shown in Figure

3.2.1.

Table 3.2.1 Salient Features of Deep Well Plan

Item Features

Diameter of well 450 mm

Depth of well 30 m

Number of wells 38 including 3 reserves

Production Capacity 6,000 m3/well

(2) Radial Collection Well

A radial collection well consists of a vertical central shaft, called a caisson and radically oriented

screen pipes. This system that can pump from shallower aquifers will be totally new, if introduced, in

Afghanistan but has been installed around the world to enhance well production. Usually the caisson is

constructed in place using the open caisson method, and the laterals are either drilled or hydraulically

projected. These construction works might be difficult for local construction contractors.

In the lower terrace Tr-1, daily water production of 15,000 m3/day (0.174 m

3/s) per well can be

expected, and thus 15 radial collection wells in total including one reserve well are necessary to meet

the design intake discharge of 2.39 m3/s. As shown in Figure 3.2.2, the 15 wells are placed at least

200m away from each other in the 140ha agricultural and hunting pool area.

Figure 3.2.2 Deployment Plan of Radial Collection Wells



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3-27

Table 3.2.2 Salient Features of Radial Collection Well Plan

Item Features

Inner Diameter of Vertical Shaft 6 m

Virtual Well Diameter 18 m

Depth of Vertical Shaft 20 m

Number of Wells 15 including 1 reserve

Production Capacity 15,000 m3/well

(3) Infiltration Gallery

Infiltration gallery is regarded as a horizontal well, and a screen pipe is placed horizontally in a

subsurface aquifer. The infiltration well system for domestic water purpose will be new to

Afghanistan, although it has been introduced for irrigation purpose according to MEW. There are a lot

of experiences of this kind of intake facilities around the world. As proved by the test gallery that was

constructed in early October 2011 by a local constructor with the help of a JWT member, its

construction is not very difficult.

The infiltration gallery is generally installed under a river. It is also proposed to install the infiltration

gallery under the riverbed of the downstream end of the Ghorband River just before the confluence

with the Panjshir River. This portion of the Ghorband River collects spring water from the upstream

and the river bank and never dries up. Not only subsurface water but also river water filtered by sands

and gravels could be collected without causing significant influences to the existing water uses in the

terraces. Due to its filtering effect, water quality of the gallery water is generally good, although this

should be confirmed by in-situ tests.

A 1,300m-long screen pipeline with a diameter of 900mm is proposed to draw the design discharge of

2.39 m3/s based on the results of the geo-hydrological surveys described in Chapter 3. Its deployment

plan is presented in Figure 3.2.3.

Figure 3.2.3 Deployment Plan of Infiltration Gallery

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Table 3.2.3 Salient Features of Infiltration Gallery Plan

Item Features

Depth of Screen Pipe 5 m below the ground

Diameter of Screen Pipe 900 mm

Length of Screen Pipe 1,300 m

(4) Intake Weir

An intake weir is a conventional structure for irrigation in Afghanistan. The weir structure is to ensure

river water intake by stabilizing the river water level. If the historical transition of the river courses of

the Panjshir and Ghorband Rivers as shown in Figure 3.2.4 is considered, the location at the existing

Sayad Bridge where the two rivers converge looks stable and suitable as a construction site of the

intake weir, although this area is a very famous tourist spot.

A 100m-long weir equipped with a 3m-high fixed weir, a spillway gate and a scouring sluice gate was

designed at the existing bridge as shown in Figure 3.2.4. This river-crossing structure enables

extensive water intake, but influences to the surrounding environment are also significant. Firstly,

floodwater is raised by the weir, resulting in extensive inundation area in the upstream. Secondly, the

very famous tourist spot might be devalued. In addition, this facility that takes river water shall be

accompanied by a rapid sand filtration treatment plant, of which high cost for construction, operation

and maintenance of the treatment plant will be a heavy burden.

Figure 3.2.4 Deployment Plan of Intake Weir

Table 3.2.4 Salient Features of Intake Weir Plan

Item Features Length of Weir 100 m Height of Fixed Weir 3 m Area of Rapid Sand Filter Treatment Plant

12 ha

Total Length of Embankment 950 m



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3-29

3.2.2 Comparison of Intake Facilities

The four facilities are compared as presented in Table 3.2.5. The deep well and radial collection well are

more economical in terms of construction cost. The infiltration gallery that is buried under the riverbed is

the most socially preferable. It aims to take remaining water left after agricultural and domestic water

uses in the upper terraces. The deep well and the radial collection well will be able to produce very good

quality water, but this will incur displeasure of local water users and long negotiation with them will

delay the implementation of the project. The intake weir seems economically and socially

disadvantageous.

The infiltration gallery tentatively seems more applicable than the others if its less social impact and low

operation and maintenance cost is considered, although further study is made on the intake facility to

select the optimum type of facility for the Panjshir Fan Aquifer based on information on experiences of

Japan, results of the test infiltration gallery and a study on other types of surface water intake facility, etc.

After the further study the optimum type of intake facility is proposed.

Table 3.2.5 Comparison of Intake Facilities (Design Intake Discharge = 2.39 m3/s)

Item Deep Well Radial Collection

Well

Infiltration

Gallery Intake Weir

Water Source Deep

Groundwater

Shallow

Groundwater

Subsurface Water

and Filtered River

Water

River Water

Water Quality Very good but

sterilization is

necessary

Very good but

sterilization is

necessary

Comparatively

good

High turbidity

requires a

treatment plant

Adverse Social Impact Significant Significant Fair Significant

Experiences in

Afghanistan

Common for

water supply

New

(Construction is

technically

difficult)

New

(Construction is

not very difficult)

Common for

irrigation

Construction Cost*

(mil. USD) Low Low

High

(Cost of sand filter

included)

High

(Cost of sand filter

included)

O&M Cost (mil.

USD/year) High High Low Very High

Land Acquisition (ha) Large Large Small Large

* Cost for land acquisition is not included.

3.3 Further Study on Intake Facility

3.3.1 Questionnaire Survey on Infiltration Gallery in Japan

(1) Outline of Questionnaire Survey

(a) Purpose of Survey

According to the preliminary study on the intake facility, the infiltration gallery seems to be one of

the most probable facilities. To further understand the mechanism of the infiltration gallery,

experiences in Japan were studied by conducting a questionnaire survey in 24 local governments

with subsurface water intake facilities whose intake volumes are about 10,000 m3 per day or more.

Site visits were also made for a few of them in September and December 2011.

(b) Items of Questionnaire

The questionnaire survey items are as follows:

Specification of infiltration gallery (diameter, length, material)

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Location and other conditions of infiltration gallery (laying location, soil condition, laying

depth)

Water quality improvement effect by infiltration gallery

Provision of water treatment plant with infiltration gallery

Countermeasures for flood and experiences of flood damage

Items of operation and maintenance (countermeasure for clogging, modification of riverbed)

(2) Results of Questionnaire Survey

(a) Specification of Infiltration Gallery

The answers pertaining to details of infiltration gallery are as follows:

There are several facilities using conventional concrete strainer pipes. However, stainless

screen pipes were adopted from the beginning of the 1980’s.

Pipes of φ800mm or more in diameter are commonly used for the concrete strainer, and

φ900mm or more for the stainless screen. As for the laying length, the shortest case is about

50m while some are more than 800m.

The design intake volume is close to 70,000m3/day for the maximum case.

(b) Condition of the Laying Location for Infiltration Gallery

The answers about conditions of the laying location for infiltration gallery are as follows:

Although some facilities have infiltration gallery under the floodplain inside or outside of

the river dike, in most cases, infiltration galleries are laid under riverbed in order to obtain a

large amount of subsurface water, or to consider geotechnical conditions.

In most cases, infiltration galleries are laid under riverbed of sand and gravel in order to

obtain a large amount of subsurface water and to avoid clogging of pipes due to silty clay. It

is preferable in this project that the infiltration galleries are laid under riverbed because the

riverbed of Ghorband River consists of gravel layer with sand which is not silty, while

floodplains outside the river course used as farmlands are mostly silty clay.

The Japanese design criteria stipulate that at least 2m depth should be secured from the

riverbed to the crown of the screen pipe. The dominant laying depth of screen pipes is 3m to

4m in order to secure the suitable water quality by thick soil filter layer and avoid flood

damage by river flow.



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3-31

Figure 3.3.1 Laying Depth of Infiltration Gallery

(c) Water Quality Improvement Effect of Infiltration Gallery

Figure 3.3.2 describes the survey results about some parameters related to water quality in

infiltration galleries during rivers in normal condition (here, normal means not flooded).

Figure 3.3.2 Water Quality of Infiltrated Water

Distribution of Laying Depth

0

2

4

6

8

10

12

14

16

0 10 20 30

Number

La

yin

g D

ep

th

Laying Depth of Infiltration Gallery

0

2

4

6

8

10

12

～1.

0m

1.0m

～2.

0m

2.0m

～3.

0m

3.0m

～4.

0m

4.0m

～5.

0m

5.0m

～6.

0m

6.0m

～7.

0m

7.0m

～

Laying Depth

Nu

mb

er

Turbidity inside of Infiltration Gallery

9 (4%)

2 (10%)

1.8 (4%)

0.8 (4%)

0.4 (4%)

0.2 (66%)

0.022 (4%)

0.02 (4%)

0.022

0.02

0.2

0.4

0.8

1.8

2

9

Unit: NTU

Color inside of Infiltration Gallery

0.5 (13%)

1 (50%)1.1 (6%)

1.6 (6%)

2 (19%)

5.4 (6%)

0.5

1

1.1

1.6

2

5.4

Detection of E. coli

Not

Detected

32%

Detected

68%

Detected

Not Detected

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In case of normal condition, in 95% of the facilities that can meet the criteria for drinking water

(Turbidity: less than 5 NTU, Chromaticity: less than 5 degrees), only one facility cannot meet the

criteria. In this one rare case, the suitable earth covering was not secured by over-dredging.

However, in the normal condition, the water quality inside the infiltration gallery will meet the

criteria for drinking water under the usual proper maintenance on the aspect of turbidity and

chromaticity. In 68% of facilities of infiltration gallery, Escherichia coli are detected and water

treatment method besides chlorination is adopted at most of the facilities except one facility for

industrial water.

The ratio of turbidity extraction obtained by comparison with the river water turbidity and

infiltrated water turbidity under the normal condition are as shown in the following table.

Table 3.3.1 Turbidity Removal Ratio by Infiltration Galleries under Normal Condition

City Name River Name River Water

Turbidity

Infiltrated Water

Turbidity

Turbidity

Removal Ratio Material

Obihiro City,

Hokkaido Satsunai 14.1 degrees 0.9 degrees 93.6%

Concrete

Strainer Pipe

Osaki City,

Miyagi Eai 5 degrees

Less than

1 degree More than 80%

Concrete

Strainer Pipe

Higashimurayam

a City, Tokyo Tama 3 degrees

Less than

0.01 degree

More than

99.7%

SUS Screen

Pipe

Sanjyo City,

Niigata Igarashi 5.5 degrees 0.4 degree 92.7%

Concrete

Strainer Pipe

Tsu City, Mie Izumo 4.8 degrees Less than

0.1 degree

More than

97.9%

Concrete

Strainer Pipe

Tottori City,

Tottori Sendai 15.3 degrees

Less than

0.1 degree

More than

99.3%

SUS Screen

Pipe

Yonago City,

Tottori Hino 1.8 degrees

Less than

0.1 degree

More than

94.4%

SUS Screen

Pipe

Ube City,

Yamaguchi Kotou 5.8 degrees 0.9 degree 84.5%

Concrete

Strainer Pipe

Hikari City,

Yamaguchi Shimada 2.2 degrees

Less than

0.1 degree

More than

95.5%

Concrete

Strainer Pipe

Matsuyama City,

Ehime Shigenobu 5.9 degrees

Less than

0.1 degree

More than

98.3%

SUS Screen

Pipe

On the other hand, regarding water quality data during flood times with high turbidity, the local

governments do not have sufficient information, but several data were available as follows:

Table 3.3.2 Maximum Turbidity in Infiltration Galleries during Flood

City Name River Name Maximum Turbidity Maximum

Color Escherichia Coli

Obihiro City, Hokkaido Satsunai River 0.9 degree (1.8NTU) 4degree 3MPN/100mℓ

Yuzawa City, Akita Omono River 0.3 degree (0.6NTU)

Setagaya City, Tokyo Tama River More than 2 degrees (4NTU)

Tsu City, Mie Izumo River 0.53degree (1.06NTU) Detection

Toyonaka City, Osaka Ina River 1.5 degrees (3NTU) 4.7degree

Habikino City, Osaka Ishi River Less than 2 degrees (4NTU)

Himeji City, Hyogo Ichi River 2.5 degrees (5NTU) 4.2degree 150MPN/100mℓ

Tottori City, Tottori Sendai River More than 2 degrees (4NTU) Detection

Matsuyama City, Ehime Shigenobu

River

20degree (40NTU)

Water-tightness failure by

well lid breakage Detection

Kochi City, Kochi Kagami River 7~8 degrees (14~16NTU) Detection

Note: Value which does not meet the criteria for drinking water



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3-33

According to the above table, some maximum turbidity data show values more than the criteria for

drinking water quality. Therefore, it is difficult to secure a safe turbidity value all the time in case

of flood.

(d) Water Treatment Plant

The survey results regarding the provision of water treatment plant with infiltration gallery are as

shown in the following figure.

Figure 3.3.3 Survey Results of Water Treatment Method

with Infiltration Gallery

According to the above results, at 90% of infiltration gallery facilities, water treatment plants are

provided aside from the chlorination facilities. The slow sand filtration, rapid filtration and

membrane filtration methods are mainly applied and, at some facilities, the ultraviolet disinfection,

de-ferrization and de-manganization systems are applied. The purposes of these treatment facilities

are: countermeasure for turbidity, cryptosporidium, removal of iron and manganese, and pH

adjustment.

(e) Existence of Countermeasure for Flood and Experience of Flood Damage

The survey results regarding the countermeasures for flood and experience of flood damage are as


Figure 3.3.4 Survey Results on Countermeasures for Flood and the Experiences

on Flood Damage

Water Treatment Method with Infiltration Gallery

Rapid Filtration

(32%)

Membrane Filtration

(21%)

None (4%)

Slow Sand Filtration

(14%)

Slow Sand Filtration・Rapid Filtration (7%)

Ultraviolet

Disinfection

(11%)

Deferrization・Demanganization

(4%)

only Chlorination

(7%)

Rapid Filtration

Membrane Filtration

Slow Sand Filtration

Slow Sand Filtration・Rapid Filtration

Ultraviolet Disinfection

Deferrization・Demanganization

only Chlorination

None

Countermeasure for Flood

None

(56%)

Riverbed

Protection

Work

(40%)

Revetment

(4%)NoneRiverbed Protection WorkRevetment

Experience of Flood Damage

Flowing out of

infiltration

gallery

(4%)Flowing out of

gabion works

(11%)

Junction well

lid breakage

(7%)

None

(78%)

NoneJunction well lid breakageFlowing out of gabion worksFlowing out of infiltration gallery

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Regarding the experiences of flood damage to infiltration galleries, no flood damage was found at

about 80% of the facilities. On the other hand, water tightness failure by junction well lid breakage

arose at two facilities, flowing out of gabion works by the force of river flow occurred at about 10%

of the facilities, and flowing out of the infiltration gallery itself occurred at one facility. This is an

example on Tama River in Tokyo where the body of infiltration gallery was exposed by the

dredging of riverbed and the riverbed was eroded because the velocity of river water flow became

faster by the erection of pier of the highway.

Regarding the countermeasures for flood, there is no countermeasure at about 56% of the facilities

and gabion works or riverbed protection works for the protection of riverbed or riverbank are

provided at about 44% of the facilities.

(f) Items of Operation and Maintenance

The survey results regarding the items of operation and maintenance of infiltration gallery are as


Figure 3.3.5 Water Treatment Method with Infiltration Gallery

The following items are reported as maintenance work for infiltration gallery:

Viewing check of screen pipes and junction wells

Mowing, monitoring of turbidity

Removal of deposited soil on riverbed (arrangement and normalization of riverbed)

Backwashing

Removal of deposited solids inside of the screen pipes

Restriction on water intake, shift change of water intake source

Dosing volume control of coagulant and adjustment of filtration volume

O&M Items

0

1

2

3

4

5

6

7

8

9

10

Non

e

Vie

win

g ch

eck

Mow

ing

Rem

oval o

f depo

site

d so

il on

rive

rbed

Bac

kwas

hing

Cleani

ng in

side

of t

he sc

reen

pipes

Res

trict

ion o

n wat

er in

take

Dos

ing v

olum

e co

ntro

l of c

oagu

lant

O&M Item

Nu

mb

er

Breakdown of O&M Items

None, Viewing

check,

Mowing

(43%)

Intake

restriction,

Dosing control

(31%)

Dredging,

Backwashing,

Cleaning

(26%)

None, Viewing check, Mowing

Dredging, Backwashing, Cleaning

Intake restriction, Dosing control



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3-35

Forty-three percent (43%) of maintenance items are “no daily maintenance” and slight daily

maintenance such as “viewing check” and “mowing.” On the other hand, medium and long term

O&M items such as “removal of deposited soil on riverbed,” “backwashing” and “removal of

deposited solids inside of the screen pipes” are 26% of the maintenance items. Operation

management such as “restriction on water intake,” “shift change of water intake source,” “dosing

volume control of coagulant and adjustment of filtration volume” are 31% of the maintenance

items.

Regarding the removal of deposited soil and arrangement of riverbed, 4 to 5 times per year of

maintenance are conducted at some facilities and once per 10 years at the other facilities. It is

thought that the maintenance frequency is different depending on the pipe laying location and

condition of soil.

There are tendencies that in case of shallow laying depth, arrangement and normalization of

riverbed shall be conducted frequently to avoid exposure of screen pipes by partial erosion in the

river channel and, at the infiltration gallery in the silty clay layer, frequent backwashing and

removal of silty layer on the riverbed are necessary.

3.3.2 Selection of Turbidity Reduction Facility for Infiltration Gallery

(1) Water Quality Criteria

Based on the water quality tests so far conducted, only turbidity and microbial items are for water

quality of the water source. Regarding microbial items, sterilization is indispensable. Turbidity is more

troublesome and might require a treatment facility.

According to the WHO guideline, drinking water must meet the following criteria with respect to

turbidity:

Turbidity is not more than 2.5 degrees (5NTU)

According to the experiences in Japan presented in the previous section, it seems difficult to secure the

safe turbidity value all the time. It has been confirmed that turbidity is lower than the criteria value

during normal times, but turbidity increases over the drinking water criteria in some records during

flood times. Therefore, water quality, especially, turbidity during the snow-melt flood season is being

observed by using the test infiltration gallery that was installed in 2011.

The above water quality test will give very useful information about the effectiveness of the infiltration

gallery. However, it is difficult to decide by such a single year observation if turbidity can be improved

by infiltration galleries so as to meet the drinking water criteria. Long time observation is necessary.

Based on the result of water quality test in the infiltration gallery, the maximum turbidity is

0.5 degree (1NTU) in dry season and 6~8 degrees (12~16NTU) in flood season. Therefore, provision

of turbidity reduction facility is necessary.

(2) Turbidity Reduction Method based on the Water Quality Condition

According to the Japanese guidelines, if average turbidity is less than 10 degrees (20NTU), the slow

sand filter method can be applied and, if not, rapid sand filter method is applied, generally. Conditions

of land availability, possibility of operation and maintenance, project cost, etc., also should be

considered in the selection of appropriate turbidity reduction method.

The optimum turbidity reduction method is selected from the following alternatives:

Only chlorine disinfection: This method is applicable for groundwater intake such as shallow

well and deep well.

Slow sand filter method: This method is applicable under the condition that the average turbidity

is less than 10 degrees (20NTU) and the maximum turbidity is less than 30 degrees (60NTU).

Rapid sand filter method: Other than the above conditions.

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The selection flow of turbidity reduction method is as shown in the following figure.

Disinfection by chlorine

Consideration of slow sand filter

method

(land restriction,O&M etc.)

Self backwashing equipment

(Saving energy type)

Avg. Terbidity:

less than 20NTU

(Avg. 10degrees) YES

NO

Max. Terdibity:

less than

5NTU (2.5degrees) YES

NO

Adoption of

rapid filter method

(weir type mixing, baffled channel

mixing）

Comparatively stable at low

turbidity

YES

NO

Instability of water quality

Consideration of suitable backwashing

method

Selection of Turbidity Reduction Method

Figure 3.3.6 Selection of Turbidity Reduction Method

(Turbidity Reduction)

Quality of target treated water: 2.5degrees (5NTU) in WHO drinking water standard

Objective treatment turbidity at this time: about 5～10degrees (10～20NTU)

(Indication Method of Turbidity)

On the Japanese drinking standard, 1 degree of turbidity is equal to 1mg kaolin per 1 liter of water.

In the WHO standard, nephelometric turbidity unit is applied. 1NTU is equal to 0.5~0.7degree.

Subsurface water intake by infiltration gallery is assumed as the optimum intake method in this project.

Therefore, the selection of turbidity reduction method is between the slow sand filter method and the

rapid sand filter method. The turbidity reduction method by only chlorination is not applicable for

subsurface water intake.

Besides, according to the pumping test result described in Chapter 3, water turbidity can be improved

very much by the infiltration gallery. However, an example of Japanese experience shows that

turbidity in an infiltration gallery rose to as high as 20 degrees (40NTU) as shown in Table 3.3.2.

Therefore, the adoption of rapid sand filter method should be taken also into consideration.



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3-37

(3) Turbidity Reduction Method

(a) Current Water Quality

In January and May 2012, a pumping test using the test infiltration gallery was conducted to

observe the raw water quality in the infiltration gallery. According to the test data, the raw water

turbidity of the infiltration gallery is as follows:

(i) Normal Time (August to March)

In the dry season, maximum river water turbidity is 0.5-6 degrees (1-12NTU) and the maximum

water turbidity in the infiltration gallery is 0.5 degree (1NTU). On the track record in Japan,

more than 70% of filtration gallery users reported that the turbidity in the gallery is less than

0.1 degree.

(ii) Flood Time (April to July)

In the flood season, river water turbidity increases due to the snowmelt spate. The maximum

river water turbidity is 50-500 degrees (100-1000NTU) or more, and the maximum water

turbidity in the infiltration gallery is 6-8 degrees (12-16NTU). According to the track record in

Japan, the maximum turbidity is 20 degrees (40NTU).

Currently the population within the watershed located upstream of the proposed location for the

intake facility is not so much. However, the water quality test indicates high concentration of coli

form bacillus in irrigation ditches which pass through villages. This high concentration of coli form

bacillus is mainly due to untreated household effluent into the ditches. Therefore, any future

change in the population and land use may have significant impacts on the source water quality.

The results of pumping test are shown in Figure 3.3.7 to Figure 3.3.9.

Figure 3.3.7 Pumping Test Results of “Test 1” in Low River Turbidity Season

Note: The test not conducted on Jan. 15, because of heavy snow.

0

10

20

30

40

50

60

70

80

90

1000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0 480 960 1440 1920 2400 2880

Dis

char

ge (

lite

r/s)

o

r

Turb

idit

y (F

TU)

Dra

wd

ow

n (

m)

Cumulative Elapsed Time (min)

Drawdown Discharge

Turbidity - Gallery water Turbidity - River water

Second pump started.


Second pump stopped.



InstrumentsTwo surface pumps used:

Firs t pump - capacity 30.5 l /s with 4" pipeSecond pump - capacity 4.3 l /s with 3" pipe

Discharge measurement: 1,110 l i ter tank and s topwatch

Turbidity measurement: HANNA Turbidity Meter HI -93703-C

Jan. 12 Jan. 13 Jan. 14 Jan. 16 Jan. 17 Jan. 18

33 l/s

1.52 m

Chapter3

Part 2






Figure 3.3.8 Pumping Test Results of “Test 2-1” in High River Turbidity Season

0

100

200

300

400

500

600

700

800

900

10000.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

0 480 960 1440 1920 2400 2880

Dis

char

ge (x

0.1

lite

r/s)

o

r

Turb

idit

y (F

TU)

Dra

wd

ow

n (

m)


Drawdown Discharge


Instruments

Surface pumps: capacity 30.5 l /s with 4" pipeDischarge measurement: 1,073 l i ter tank and s topwatch Turbidity measurement: HANNA Turbidity Meter HI -93703-C

0.1

48

36

0.1

29

0.0

272

226

14

0.2 0.0 0.0

27

159

124

141

160

42

308

454

347

901

> 1000

630

464 467

405

190

16

河川水が埋渠施

設上を流下

May 22 May 23 May 24 May 25 May 26 May 27



Chapter3

Part 2




3-39

Figure 3.3.9 Pumping Test Results of “Test 2-2” in High River Turbidity Season

0

100

200

300

400

500

600

700

800

900

10000.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

0 480 960 1440 1920 2400 2880

Dis

char

ge (x

0.1

lite

r/s)

o

r

Turb

idit

y (F

TU)

Dra

wd

ow

n (

m)


Drawdown Discharge


Instruments

Surface pumps: capacity 30.5 l /s with 4" pipeDischarge measurement: 1,073 l i ter tank and s topwatch Turbidity measurement: HANNA Turbidity Meter HI -93703-C

0.0

49

85

16 12

226

0.0 3.1 0.0

> 1000

720

River water flow

covering the whole facility

site.

> 1000

141

> 1000 > 1000

May 29 May 30 May 31 June 1 June 2 June 3

River water flowing through a 4 m-width ditch over the facilityRiver water flowing through a 1 m-width ditch over the facility

At 25 minutes after strat of pumping, a sinkhole apperared and much water flowed into it. The location is a point where an observation pipe had been installed and remooved. By filling the hole with gravel and sand, the flowing-in of water stopped.

Chapter3

Part 2






(b) Selection of Optimum Turbidity Reduction Facility for Infiltration Gallery

The infiltration gallery as intake facility requires an additional turbidity reduction facility because

the raw water turbidity, especially at flood time, needs to be improved to satisfy the water quality

standard of drinking water. The comparison of turbidity reduction facilities is shown in Table

3.3.3.

Table 3.3.3 Selection of Turbidity Reduction Method

Intake

Facility

Evaluation Item

Alternative A

(Infiltration Gallery + Slow Sand Filter)

Alternative B

(Infiltration Gallery + Rapid Sand Filter)

Operation

Method

Under both normal and flood conditions, raw

water is treated at the slow sand filter facility.

Under normal conditions, turbidity is low and

direct filtration (suitable for treating raw

water with low turbidity and color) is

conducted by adding the reduced amount of

coagulant right before the sand filter. Under

flood conditions, the conventional treatment

is conducted.

Characteristics of

Filtration System

Filtration rate is 4 to 8 m/day. Suitable for raw

water with low turbidity and stable water

quality. Microbes reproduced on the surface

or in the layer of fine sand decompose

dissolution materials and un-dissolved

substances.

Filtration rate is 120 to 150 m/day. The filter

bed consists of sand coarser than the bed

material used for the slow sand filter. The

conventional treatment facility consists of

flocculation with a chemical coagulant and

sedimentation before the filtration.

Range of

Turbidity

Treatment

Approximately lower than 10degrees

(20NTU).

It is applicable for the raw water turbidity in

the infiltration gallery in this project site.

No limitation.

Description of

Facility

(Intake Volume:

207,000 m3/day)

Receiving well, Sedimentation Basin, Slow

Sand Filter, Water Reservoir, Sludge Bed,

Chlorination, Control Building (laboratory)

Receiving well, Mixing Basin, Flocculation

Basin, Sedimentation Basin, Rapid Sand

Filter, Water Reservoir, Sludge Bed,

Chlorination, Control Building (laboratory)

Land

(without Intake

Facility)

The area of sand filter is larger in order to

treat the intake flow of 207,000m3/day at the

low filtration speed (6m/day).

About 15.5ha

The land area of this method can be reduced

compared with the area of slow sand filter.

About 7.3ha

Operation and

Maintenance

Retention plan for skilled workers is required

to conduct periodical sand removal in the

filter basin. To maintain a suitable filtration

function, filtration sand needs to be added

periodically. Dosing volume control of

coagulant is not necessary.

This is a flexible turbidity reduction system

which can deal with turbidity fluctuation. It

requires additional electricity cost to operate

facilities for chemical dosing and

backwashing which requires periodical

maintenance. Dosing volume control of

coagulant by jar test is necessary.

Adoptability on

this Project

Operation and maintenance of this method is

much easier than rapid sand filter, although

Periodical surface sand excavation is

necessary.

Coagulation reagent and the filter sand for

rapid filter method is not available in

Afghanistan and cannot be procured locally.

Therefore, there is a possibility that daily

operation could not be performed properly.

Project Cost Preliminary Cost: 24.4 mil USD

O&M Cost: 0.5 mil USD/year

Preliminary Cost: 17.5 mil USD

O&M Cost: 1.6 mil USD/year

Evaluation

Result Adopted

The contents of O&M and cost breakdown for each kind of turbidity reduction facility are shown in

Table 3.3.4.



Chapter3

Part 2




3-41

Table 3.3.4 Contents of O&M and Cost Breakdown of Turbidity Reduction Facilities

Slow Sand Filter Rapid Sand Filter

Operation and

Maintenance 【Control of Turbidity】

It is possible to treat water with an

average turbidity of 20NTU and a

maximum turbidity of 60NTU.

【Control of Turbidity】

It is possible to correspond to high levels

of turbidity.

【Dosing Volume Control of Chemicals】

Dosing volume control of coagulant is

not necessary.

【Dosing Volume Control of Chemicals】

Dosing volume control of coagulant by

jar test is necessary.

【Maintenance of Sand Filter Basin】

Periodical surface sand excavation of

filter layer is necessary due to the

accumulation of suspended substances

and formation of microbial layer on the

surface of the filter sand.

Periodical backfill of filter sand is

necessary.

Maintenance of filter layer of rapid

filtration system by surface washing and

back washing is not necessary.

【Maintenance of Sand Filter Basin】

Maintenance of sand filter basin by

surface washing and back washing is

necessary.

Pressure pump shall not be applied for

back washing and differential head

between each filtration tank shall be

made use for the back washing.

【Correspondence to the filtration hondrance】

1.5cm thickness of surface sand

excavation shall be performed at 2

months interval for 32 filter sand basins.

In preparation for unexpected level of

turbidity in the raw water in an accident,

sedimentation basin shall be provided.

【Correspondence to the filtration hondrance】

It is possible to correspond to high levels

of turbidity by volume control of

coagulant.

Clogging of filter sand layer shall be

prevented by surface washing and back

washing.

【O&M of Machinery】

O&M of sand washing machine and belt

conveyor is necessary.

【O&M of Machinery】

O&M of lift pump and chemical dosing

pump is necessary.

【Contents of O&M】

Filter sand excavation (about 50 workers

per day are required)

Monitoring of water level and water

quality

Operation of valves

Refill of filter sand

【Contents of O&M】

Dosing volume control of coagulant

Surface washing and back washing of

sand filter basin

Monitoring of water level and water

quality

Operation of valves

Refill of filter sand

【O&M Cost】

The main component of O&M cost is the

labor cost for filter sand excavation.

【O&M Cost】

The main component of O&M cost is the

cost of chemicals such as coagulant.

Cost Foundation Work : 1.7

Structure Work : 15.2

Filter Sand & Gravel : 2.4

Ancillary Work : 1.1

Plumbing Work, etc. : 4.4

Total : 24.4 mil USD

Foundation Work : 0.3

Structure Work : 8.2

Filter Sand & Gravel : 0.3

Under Drain : 4.5

Ancillary Work : 1.2

Plumbing Works, etc. : 2.9

Total : 17.5 mil USD

Labor Cost : 0.36

Equipment Replacement : 0.08

Refill of Filter Sand &

Gravel

: 0.07

Total : 0.5 mil USD/year

Labor Cost : 0.00

Electric Cost : 0.05

Chemical Cost : 1.49

Equipment Replacement : 0.05

Refill of Filter Sand &

Gravel

: 0.01

Total : 1.6 mil USD/year

The breakdown of O&M cost for each kind of turbidity reduction facility is shown in Table 3.3.5.

Chapter3

Part 2






Table 3.3.5 Breakdown O&M Cost for Turbidity Reduction Facilities

Slow Sand Filter Rapid Sand Filter

Labor Cost 50 skilled workers x 12 months x 600USD/month

= 360,000 USD ≒ 0.36 mil USD

Not so many personnel are necessary for the

operation of rapid sand filter facility. Therefore,

operation personnel of water conveyance booster

station will also conduct operation of turbidity

reduction facility (rapid sand filter).

Chemical Cost No need Dosing rate = 10mg/ℓ

10mg/ℓx 207,000m3/day x 1000 =2,070kg/day

2,070kg/day x 100/15 = 13,800kg/day (15% of

purification)

13,800kg/day x 30days x 2months x 1.8USD/kg

=1,490,400USD ≒ 1.49 mil USD

Refill of Filter

Sand & Gravel

57,600m3 x 0.025 = 1,440m3/year

1,440m3 x 49USD/m3 = 70,560 USD ≒ 0.07 mil

USD

2,200m3 x 0.025 = 55m3/year

55m3 x 254USD/m3 = 13,970 USD ≒ 0.01 mil

USD

Rehabilitation and

Replacement Cost

of Equipment

Rehabilitation of Equipment : 0.02 mil USD (2%

of initial cost)

Replacement of Equipment : 0.06 mil USD

(Replacement of 15 years interval)

Rehabilitation of Equipment : 0.01 mil USD (2%

of initial cost)

Replacement of Equipment : 0.04 mil USD

(Replacement of 15 years interval)

In the comparison between the rapid filter method and the slow sand filter method in Table 3.3.3 to

Table 3.3.5 above, a) back-washing of filter bed; b) dosing control of chemicals; and c) sludge

treatment are necessary in the rapid filter method. On the other hand, a) periodical excavation of

filter sand and b) washing (recycling) of excavated sand are necessary in the slow sand filter

method.

Regarding the feature of slow sand filter method and rapid sand filter method, both types have

merits and demerits. From to the following reasons, however, the Alternative A: Slow Sand

Filter Method is deemed to be the optimum selection.

Coagulation reagent and filtration sand for the rapid filter method is not available in

Afghanistan and cannot be procured locally. Therefore, there is a possibility that daily

operation could not be performed properly.

There is no track record on the provision of rapid filter treatment facility in Afghanistan.

There is a water treatment facility in Charikar and the treatment type of this facility is slow

sand filter method with coagulation basin and sedimentation basin. In the operation of this

treatment facility, coagulation reagent is not applied in spite of the surface water treatment

facility, and these chemical materials are not procured periodically.

There is information that import of sulfate which is raw material of flocculants is prohibited

in Afghanistan.

3.3.3 Applicable Methods of Surface Water Intake

In Section 3.2 intake weir is tentatively compared to the other intake types as a representative of surface

water intake facilities. In addition to the intake weir, intake port, floating and skew weir are also

conceived as the surface water intake facility for this area. Therefore, these facilities are compared in

Table 3.4.1 to select the most applicable surface water intake type. In conclusion, the intake weir that

enables stable water intake even in the dry season is selected.



Chapter3

Part 2




3-43

Tab

le 3

.3.6

S

elec

tion

of

Op

tim

um

Su

rface

Wa

ter

Inta

ke

Alt

ernat

ive

1:

Inta

ke

Po

rtA

lter

nat

ive

2:

Inta

ke

Wei

rA

lter

nat

ive

3:

Flo

atin

gA

lter

nat

ive

4:

Skew

Wei

r

Outl

ine

Fig

ure

Fac

ilit

y

Outl

ine

・In

take

po

rt w

ith s

cree

n,

mai

nte

nan

ce g

ate,

and

san

d b

asin

at

river

ban

k.

This

isa

nat

ura

lin

flo

wsy

stem

whic

hd

oes

no

t

hei

ghte

n t

he

wat

er l

evel

by w

eir.

・P

um

pin

gro

om

and

elec

tric

roo

msh

all

be

pro

vid

edat

the

level

of

mo

reth

anth

em

axim

um

wat

erle

vel

inth

efl

oo

d

seas

on.

・T

oen

sure

the

inta

ke

wat

erle

vel

,o

ver

po

ur

or

reli

efgat

e

cro

ssin

g t

he

river

chan

nel

shal

l b

e p

rovid

ed.

・T

op

reven

tsu

bm

ersi

on

of

farm

land

by

dam

med

up

wat

er,

pro

vis

ion o

f ri

ver

ban

k a

nd

rev

etm

ent

is n

eces

sary

.

・D

raw

wat

er b

y p

um

p i

nst

alle

d o

n t

he

stee

l b

arge.

・E

lect

ric

roo

msh

all

be

pro

vid

edat

ale

vel

of

mo

reth

anth

e

max

imum

wat

er l

evel

in t

he

flo

od

sea

son.

・In

take

wei

r is

asl

ant

inst

alle

d t

o t

he

river

flo

w d

irec

tio

n.

・W

eir

isst

ruct

ure

dw

ith

confo

rmat

ional

ly-e

asy

wo

od

en

mat

tres

s, s

tone

pit

chin

g a

nd

co

ncr

ete.

Mer

it

・S

edim

enta

tio

nin

tran

smis

sio

np

ipes

and

the

attr

itio

no

f

pum

p c

an b

e d

ecre

ased

by i

nst

alli

ng t

he

sand

bas

in.

・S

ince

elec

tric

roo

mis

pro

po

sed

atri

ver

terr

ace,

mai

nte

nan

ce o

f p

um

p a

nd

ele

ctri

cal

par

ts i

s re

lati

vel

y e

asy.

・T

he

stru

cture

may

dis

turb

riv

er w

ater

flo

w.

・It

isp

oss

ible

tod

raw

the

wat

erst

able

ind

ryse

aso

nb

y

dam

min

g-u

p o

f ri

ver

wat

er.

・S

ince

the

vel

oci

tyo

fri

ver

wat

erfl

ow

islo

wer

edb

yin

take

wei

r, s

edim

ent

effe

ct i

s go

tten

.

・C

onst

ruct

ion c

ost

is

rela

tivel

y l

ow

.

・It

isp

oss

ible

toch

ange

the

inta

ke

po

int

bec

ause

of

flo

atin

g

syst

em.

・T

he

resi

stan

ceb

yw

ater

flo

wca

nb

ed

ecre

ased

bec

ause

the

wei

r is

sla

nte

d o

ff t

o t

he

flo

w d

irec

tio

n.

・T

he

wei

rhas

funct

ion

for

guid

eb

ank

and

mak

esri

ver

wat

er

inta

ke

smo

oth

.

・In

tro

duci

ng

casc

ade

or

slo

pe

syst

emat

do

wnst

ream

of

wei

r

can m

ake

flo

w i

nte

rtia

fo

rce

dec

reas

e.

Def

ect

・O

nth

ep

lannin

go

fin

take

po

rtat

the

river

ban

k,

itis

nec

essa

ryto

take

the

rela

tio

nb

etw

een

the

loca

tio

no

fin

take

po

rtan

dth

eri

ver

chan

nel

route

into

consi

der

atio

n.

Itis

also

nec

essa

ryto

consi

der

aco

unte

rmea

sure

agai

nst

the

clo

ggin

g

of

inta

ke

po

rt a

t th

e al

luvia

l ri

ver

sec

tio

n.

・T

he

sand

dep

osi

ted

on

sand

rese

rvo

irsh

all

be

dis

char

ged

per

iod

ical

ly.

・P

um

pin

gro

om

and

elec

tric

roo

msh

all

be

pro

vid

edat

the

level

of

mo

re t

han

the

max

imum

wat

er l

evel

in f

loo

d s

easo

n.

・A

cces

sro

ads

shal

lb

ep

rovid

edno

tto

mak

eth

ep

rop

ose

d

inta

ke

po

rt i

sola

ted

in f

loo

d p

lain

.

・C

onst

ruct

ion c

ost

is

exp

ensi

ve.

・In

ord

erto

pre

ven

tth

esu

bm

ersi

on

of

farm

land

fro

m

dam

med

up

wat

er,

pro

vis

ion

of

river

ban

kan

dre

vet

men

tis

nec

essa

ryat

the

no

emb

ankm

ent

sect

ion

and

firm

app

roac

h

revet

men

tsh

all

be

pro

vid

edto

pro

tect

the

wei

rb

od

yat

the

up

stre

am a

nd

do

wnst

ream

po

rtio

n o

f th

e w

eir.

・G

ate

equip

men

tsh

all

hav

een

ough

dis

char

ge

cap

acit

y

bey

ond

max

imum

flo

od

wat

er f

low

.

・W

ater

pum

pin

gm

ayb

eim

po

ssib

lein

dry

seas

on

bec

ause

the

inta

ke

wat

er l

evel

co

uld

no

t b

e se

cure

d.

・M

ainte

nan

ceis

inco

nven

ient

bec

ause

pum

peq

uip

men

tis

inst

alle

d i

n t

he

river

chan

nel

.

・A

ttri

tio

no

fp

um

pim

pel

ler

by

suct

ion

of

sand

isas

sum

edin

case

that

the

wat

er l

evel

is

low

.

・D

ura

bil

ity

of

stee

lb

arge

issh

ort

bec

ause

of

rust

and

corr

osi

on.

・It

isno

tsu

itab

lein

case

of

long

dis

tance

fro

mth

eri

ver

sho

re t

o t

he

cente

r o

f ch

annel

ro

ute

.

・T

he

pri

nci

ple

that

the

river

stru

cture

shal

lb

eb

uil

to

na

per

pen

dic

ula

rd

irec

tio

nto

the

river

wat

erfl

ow

dir

ecti

on

may

be

infr

inged

.

・S

ince

the

inta

ke

wei

ris

asla

nt

inst

alle

dto

the

river

flo

w

dir

ecti

on,

river

ban

ker

osi

on

atd

ow

nst

ream

of

the

wei

rw

ill

occ

ur.

・In

take

po

rtm

ayb

ecl

ogged

bec

ause

the

inta

ke

site

is

allu

via

l se

ctio

n a

nd

sed

imen

t d

epo

siti

on i

s re

mar

kab

le.

・D

isch

arge

of

flo

od

wat

eris

imp

oss

ible

inca

seo

fla

rge

flo

od

bec

ause

of

the

fixed

wei

r.

Ap

pli

cab

ilit

y

・In

case

ther

eis

sed

imen

tat

the

mo

uth

of

inta

ke

po

rt,

the

inta

ke

vo

lum

em

ayno

tb

een

ough

inth

ed

ryse

aso

n.

Itis

nec

essa

ryto

dis

char

ge

the

dep

osi

ted

sand

atth

em

outh

of

the

inta

ke

po

rt.

・P

rovis

ion

of

river

ban

kag

ainst

sub

mer

sio

no

ffa

rmla

nd

is

nec

essa

ry.

This

syst

emis

no

tsu

itab

leb

ecau

seo

fth

ed

iffi

cult

y

of

land

acq

uis

itio

n f

or

emb

ankm

ent

at t

his

sit

e.

・T

he

app

roac

hre

vet

men

tis

nec

essa

ryb

ecau

seo

fp

ote

nti

al

ban

ker

osi

on

by

gen

erat

ion

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1000

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1800

200

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1000

02

550

0

700

0

3000

600

4400

02

00

03

00

0

200

0

a

a

c

cb

025

50m

05

10m

05

10m

02m

現況平面図

現況平面図

a-aの断面図

現況平面図

b-bの断面図

現況平面図

c-cの断面図

Chapter3

Part 2






3.4 Optimum Intake Facility

3.4.1 Selection of Optimum Intake Facility

Following the above study, the proposed intake facilities are compared again, in detail, as presented in

Table 3.4.1. There are three (3) main intake categories: (1) taking groundwater by deep well; (2) taking

subsurface water by infiltration gallery; and (3) taking surface water by intake weir. As for the radial

collection well that appears in Table 3.2.5, it is excluded from this comparison because of its significant

social impact, technical difficulty and higher maintenance cost. Depending upon the source water

turbidity, the infiltration gallery is provided with slow sand filter and the intake weir is provided with

rapid sand filter respectively as turbidity reduction facility. Breakdown of cost estimation are

summarized in ANNEX Part 2_1.

Table 3.4.1 Selection of Optimum Intake Method Intake

Method

Evaluation

Item

Deep Well Infiltration Gallery

(with Slow Sand Filter)

Intake Weir

(with Rapid Sand Filter)

Land

(Farmland)

Occupation

Considerable farmland is

occupied by well, conveyance

pipe and patrol road.

Occupation is minimized since

the water collection facility is

located within the river channel.

Adjacent farmland and

commercial facilities are

submerged by heading-up of

water.

Evaluation × Evaluation ○ Evaluation ×

Water Quality Turbidity reduction facility is not

required for treating turbidity.

However, it cannot react to the

future potential deterioration in

water quality.

Filtration effect by the screen

pipe will improve the water

quality which can reduce the

burden at the turbidity reduction

facility.

Greater burden for the turbidity

reduction facility since surface

water with high turbidity needs to

be treated by rapid sand filter.

Evaluation ○ Evaluation △ Evaluation ×

Operation and

Maintenance

Several well pumps need to be

renewed periodically.

Periodical sediment removal and

cleaning of the screen pipe are

required.

Chemicals such as flocculants

will be required for the treatment

of surface water at the turbidity

reduction facility. Sludge

handling, and maintenance for

switch gears of gates, wire, and

roller are required.

Evaluation △ Evaluation △ Evaluation △

Social

Environment

Considerable impact on the

surrounding environment since

reduction in groundwater table

may be recorded within the zone

of influence of the well

discharge.

Low impact on the surrounding

environment since no

aboveground structure is

constructed.

Greater impact on the

surrounding environment since

the aboveground structures is

constructed. Existing resort will

be affected.

Evaluation × Evaluation ○ Evaluation ×

Constraints of

Construction

Possible to construct using local

technique.

Possible to construct using local

technique.

Placing of concrete under the

water condition is difficult.

Evaluation ○ Evaluation ○ Evaluation △

Economic

Efficiency

Initial cost is low. The power

facilities such as submersible

pumps are dispersed, thus

operation efficiency is low and

electricity expenses become

higher.

As compared to deep well option,

initial cost is much higher, but

O&M cost is reasonably low.

As compared to other option,

O&M cost is much higher.

Initial Cost: 29 mil USD

OM Cost: 4.8 mil USD





Evaluation ○ Evaluation ◎ Evaluation ×

Evaluation

Result

Adopted

Note: ◎:Excellent, ○:Good, △:Fair, ×:No Good



Chapter3

Part 2




3-45

To operate the well intake at the river terrace used as farmlands, several construction works are required,

including well installation, conveyance pipe laying and management road construction. By considering

the time spent for gathering information on landowners and land acquisition prior to the construction, the

well intake method is not recommended. Moreover, it is considered that the deep wells will lower the

groundwater level in the farmlands, significantly.

The intake weir that requires a treatment plant of rapid sand filter has a problem of high operation and

maintenance cost due to high energy and chemical cost. This is a big financial burden to the water supply

provider.

In the case of subsurface water intake using the infiltration gallery, occupancy of farmlands is minimized

since the structure is installed under the riverbed. In addition, no significant impact to the surrounding

environment is expected from the infiltration gallery. Stable and high water quality achieved by the filter

effect of the installed gallery can minimize the burden on the turbidity reduction facility.

In conclusion, the infiltration gallery is recommended as the optimum intake facility for this project.

3.4.2 Consideration Points for Application of Infiltration Gallery

For applying the infiltration gallery as the intake method, following points should be considered:

(1) Consturction

Particle size of gravel around the screen pipe shall be adjusted orderly.

Prescribed earth covering shall be secured above the crown of the screen pipe.

Careful compaction shall be required after the screen pipe laying.

(2) Maintenance

Maintenance works should include:

Viewing check of screen pipes and junction wells

Mowing, monitoring of turbidity

Removal of deposited soil on riverbed (arrangement and normalization of riverbed)

Removal of deposited solids inside of the screen pipes

Restriction on water intake (valve operation) in case of high turbidity

It is important to perform the above mentioned items properly on the construction phase and operation

phase so as not to clog the screen pipe and for securing the stable water intake.

As for the turbidity reduction facility provided to the infiltration gallery, a sedimentation basin shall be

provided before the filtration basin in preparation for unexpected level of high turbidity in the raw water

in an emergency case. The sedimentation basin is a countermeasure to protect the turbidity reduction

facility from high turbid water and to maintain its water purification capability sustainably.

Chapter3

Part 2






3.5 Water Development Potential

The next step after the selection of the intake facility is to examine if the design water discharge is

available and if it is allowed to take such amount of water.

3.5.1 Water Budget at Gallery Site

(1) Water Flow near Galley

Figure 3.5.1 illustrates the water flow near the

proposed infiltration gallery that will be installed

under the riverbed of the Ghorband River just

upstream of the confluence with the Panjshir

River.

River water from the upstream once disappears

under the riverbed and appears again after it

flows underground several kilometers in dry

season. Spring water generated in the lower

terraces on the river bank gathers via canals to

this lowest river stretch of the Ghorband River

where the infiltration gallery will be installed.

The water is regarded as remaining water that

was left after water uses in the Panjshir Fan area.

(2) Estimation of Ghorband River Discharge

In order to know how much water is available for the infiltration gallery, JWT tried to roughly estimate

the Ghorband River water discharge at the gallery site where river water and spring water gathers by

using observed river discharge data.

Figure 3.5.2 River Network of Ghorband River

There are five discharge stations near the Panjshir Fan; namely, (1) Bagi i Lala on the Salang river;

(2) Gulbahar on the Panjshir River; (3) Gulbahar on Shatul River; (4) Pul-i-Ashawa on the Ghorband

River; and (5) Shukhi on the Panjshir River. The four stations except for Shukhi are all located at the

exit points of the rivers to the Panjshir Fan area.

Figure 3.5.3 compares the monthly discharge of Shukhi Station with the total monthly discharge of the

four stations. The two hydrographs are very similar, although the total discharge is, generally, slightly

smaller than that of the Shukhi Station. From this figure, it is understood that the total discharge at the

Gulbahar

Gulbahar

Bagi i Lala

Pul-i-Ashawa

Shukhi

Shatu

l R

iver

Sala

ng R

iver

Ghorband RiverGhorband River

203km2

50

km

2

396km2

42

km

23

2km

2

4,0

40

km

2

39km2 14km2

17

4km

2

316km2

Gulbahar Dam

(proposed site)

Salang Dam

(propsed site)

Panjs

hir R

iver

(10,887km2)

(3,530km2)

(438km2)

LEGEND

: Catchment Area

: River Network

: Hydrological Station

2,0

51

km

2

Barikab River

Omarz

Panjshir River

2,2

20

km

2

1,310km2

Panjshir Fan

Infiltration Gallery

Figure 3.5.1 Water Flow near


Riverbed Water

(from the Ghorband river

basin and groundwater

basin)

Irrigatio

n W

ate

r from

Gh

orb

and R

iver

groundwater recharge

Spring Water

(from groundwater basin)

River Water

(from the Ghorband river basin)

Sayad .Bridge

: boundary of river basin

: expected boundary of

groundwater basin

LEGEND



groundwater basin



groundwater basin

LEGEND

This river section is

dried up in dry season.


Panjs

hir

Riv

er



Chapter3

Part 2




3-47

upper stations contributes very much to the formation of discharge of Shukhi Station. This means that

most of the river water at the upper stations, even if once taken for the irrigation purpose, finally

returns to the rivers, passing underground or through canals on the way.

In addition, contribution of spring water is also important, especially in the low water season. There is

a small continuous gap from November to February between the two hydrographs of the Shukhi

Station and the total discharge of the four stations in Figure 3.5.3. This gap seems to be groundwater

that is stored in the terrace areas near the river during the irrigation season from March to October and

springs out from the ground to feed the rivers.

Data Source: MEW

Figure 3.5.3 Comparison of Monthly Discharges

Therefore, the river discharge at the infiltration gallery is composed of the river discharge of the upper

rivers and the spring water. Since it is very difficult to estimate the spring water, it is assumed that the

0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1968 - Nov. 1969

Shukhi①+②+③+④

0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1969 - Nov. 1970


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1971 - Nov. 1972


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1970 - Nov. 1971

Shukhi

0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1972 - Nov. 1973


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1973 - Nov. 1974


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1974 - Nov. 1975


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1975 - Nov. 1976


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1976 - Nov. 1977


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1977 - Nov. 1978


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 1978 - Sep. 1979


0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Oct. 2008 - Sep. 2009Shukhi①+②+③+④

0

100

200

300

400

500

11 12 1 2 3 4 5 6 7 8 9 10

(m3/s)Oct. 1967 - Nov. 1968

29.4 30.6

0

100

200

300

400

500

10 11 12 1 2 3 4 5 6 7 8 9

(m3/s)Average (13 years)


Chapter3

Part 2






discharge at the gallery is equal to the sum of the discharges of the Bagi-i-Lala and Pul-i-Ashawa

Stations for simplicity. Since the contribution of the spring water is neglected, the assumption is

conservative for the water budget.

Table 3.5.1 gives estimated monthly discharges by the above assumption. According to this table, the

minimum discharge is 6.3 m3/s of February 1971. Since the monthly data are complete for 17 years, it

can be said that the return period of the minimum discharge is once in 17 years. In other words, at least

6.3m3/s is available at the infiltration gallery site with a water security level of once in 17 years.

Table 3.5.1 Estimated Monthly Discharge of Ghorband River at Infiltration Gallery

unit: m3/s

Year Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Total

1961/62 16.2 17.4 18.1 17.2 17.0 19.6 48.9 63.7 68.8 36.3 19.6 19.6 952.8

1962/63 12.9 13.8 12.5 11.5 10.9 18.0 39.7 100.7 106.9 50.1 17.3 11.0 1,067.9

1963/64 10.5 12.2 11.7 11.2 12.3

1964/65 11.4 11.7 12.1 27.5 79.7 127.5 140.4 105.8 37.4 18.7

1965/66 16.4 16.3 14.9 13.1 14.0 24.0 60.7 78.1 104.0 37.4 16.8 13.0 1,074.0

1966/67 12.8 12.6 11.2 9.7 9.2 15.8 62.0 71.2 96.2 47.9 21.8 16.1 1,016.8

1967/68 13.0 12.2 12.7 11.6 12.1 28.3 66.3 86.0 152.4 71.3 24.3 15.3 1,330.3

1968/69 15.5 15.6 17.7 13.3 15.2 38.6 68.4 71.4 105.5 56.1 23.2 15.1 1,198.4

1969/70 16.0 18.2 12.3 10.6 10.2 14.1 38.3 61.9 48.8 20.6 10.6 9.2 712.3

1970/71 11.2 11.8 10.8 8.1 6.3 15.2 33.1 53.7 32.1 14.2 7.3 6.7 554.8

1971/72 7.8 9.5 9.4 8.5 8.4 33.3 60.9 110.8 123.1 55.1 20.6 12.4 1,212.2

1972/73 14.5 15.0 13.4 13.8 14.0 31.2 76.6 116.9 100.8 38.8 18.9 12.9 1,229.2

1973/74 13.2 13.6 12.5 11.9 10.9 16.9 41.7 62.7 62.0 23.6 10.2 9.5 759.3

1974/75 11.4 11.2 10.4 9.2 8.5 15.2 52.4 77.2 88.0 43.0 13.8 7.7 915.9

1975/76 10.0 11.1 12.3 11.1 9.0 17.3 64.8 104.4 98.6 48.8 15.6 11.6 1,092.6

1976/77 12.1 12.0 12.4 12.2 12.8 22.3 38.2 49.1 65.0 22.3 9.8 7.9 725.9

1977/78 9.6 12.0 11.8 12.1 13.0 23.3 71.0 87.9 63.8 30.8 14.2 11.2 948.8

1978/79 10.6 12.3 12.1 10.7 9.2 16.7 68.6 72.4 98.1 52.7 23.9 9.0 1,042.6

1979/80 10.0 14.2 10.9 8.7 952.8

2008/09 10.2 12.6 11.2 10.9 11.4 22.1 57.0 106.2 112.9 36.5 16.9 8.9 1,097.0

2009/10 14.4 14.6 13.4 14.3 16.2 28.5 58.3 124.0 94.2 41.2

Max. 16.4 18.2 18.1 17.2 17.0 38.6 79.7 127.5 152.4 105.8 37.4 19.6 1,330.3

Min. 7.8 9.5 9.4 8.1 6.3 14.1 33.1 49.1 32.1 14.2 7.3 6.7 554.8

Average 12.4 13.4 12.5 11.5 11.6 22.5 57.2 85.6 92.7 43.8 17.9 12.0 995.9

On October 3, 2011, JWT carried out

discharge measurement of one of the three

streams in the Ghorband River near the test

site of the infiltration gallery, as shown in

Figure 3.5.4. The measured discharge was about 4 m3/s. Considering that this discharge was just for

one of the three main streams of the Ghorband River, it is presumed that 10 m3/s flow in the total width

of the river, at least. In addition, the year 2011 was a less precipitation year (Drought probability is

Figure 3.5.4 Location of Discharge

Measurement



Chapter3

Part 2




3-49

about 1 in 6 years) according to the 52-year precipitation record of Jabul Suraj Station. Therefore, the

estimation result of 6.3 m3/s as the minimum discharge in the 17 years seems reasonable.

(3) Water Availability

The estimated minimum river discharge of 17-year return period is 6.3 m3/s; namely, the river water

exceeds the design discharge of 2.39 m3/s with a significant margin. Accordingly, it may be concluded

that at least the design discharge of 2.39 m3/s is available at the installation site of the infiltration

gallery.

3.5.2 Drawdown of Groundwater Level

(1) Outline

Groundwater will be drawn down by the proposed infiltration gallery as shown in Figure 3.5.5. If it is

significant in the neighboring terrace areas, it might affect water uses for irrigation, domestic use,

hunting, etc. It is expected that the infiltration gallery that will be buried under the riverbed of the

Ghorband River will not cause significant drawdown of groundwater in the surrounding agricultural

areas. To verify this hydraulically, a profile model analysis along a representative cross section in the

area was carried out. In addition, areal drawdown made by the development was calculated by areal

model simulation, though some assumptions were required due to shortage of data.

Figure 3.5.5 Groundwater Flow near Infiltration Gallery

<Present Condition>

<After Development - Intake facility between river f low and river side>

<After Development - Intake facility between river f lows>

Drawdown amount depends on:1) Intake amount of water,2) Richarge from irrigation on field,3) Induced recharge from canals and ponds,4) Induced recharge from Ghorband river,5) Permeability of aquifer, and6) Thickness of aquifer.

Seeping-in Canals

Seeping-out Canals

Recharge from irrigation

Seeping-in River

Seeping-out River

Pond

Head drawdown reduces spring discharge and well water depth

WellSpring

Intake of groundwater

Aquifer

Aquifer

Ghorband RiverTr-1 TerraceTr-3 Terrace

Seeping-in & Seeping-out River

Intake of groundwater

Aquifer

Small or slight drawdown

Schematic potential line

Chapter3

Part 2






(2) Profile Analysis

(a) Model and Method

The method of steady state saturated and unsaturated two-dimensional seepage analysis with FEM

is applied for a typical profile in the area with average conditions. Figure 3.5.6 shows the section

line. Figure 3.5.7 shows the calculation mesh and model materials. Uniform groundwater recharge

is assumed on Tr-3 and Tr-3 terraces. No recharge is given to Tr-1 terrace. The program used for

the analysis is "DTRANS 2D-EL", which is an open program developed by Prof. Nishigaki,

Okayama University, Japan, and his colleagues.

(b) Calculation cases

The following cases were calculated:

Case 0: Present condition with no infiltration gallery.

Case 1: An infiltration gallery is installed between a river flow and the riverside.

Case 2: An infiltration gallery is installed between two river flows.

(c) Results

Figure 3.5.8 shows the calculated potential lines. The results are summarized as follows (see

Figure 3.5.9):

1) If the infiltration gallery is installed between a river flow and the riverside (Case 1), that is,

there is no recharge source between the infiltration gallery and the spring line, 1m to 2.5m

drawdown in the lowland and about 40% decrease of spring discharge might occur.

2) If the infiltration gallery is installed between river flows (Case 2), the maximum drawdown in

the lowland is calculated to be about 0.2m and decrease of spring discharge does about 8%.

3) Therefore, it is desirable to locate water flow between the infiltration gallery and the riverbank

to suppress the drawdown in the nearby terraces by the so-called “water curtain effect.”



Chapter3

Part 2




3-51

Figure 3.5.6 Section Line of Profile Model

Figure 3.5.7 Model Materials and Calculation Mesh

0 500 1000 1500 2000 2500 3000 3500 4000 m

20001500 1750 2250 m

3000 3250 m2750

4000 42503750 4500 m

1300

1400

1500

1600

1345

1457.5

1491

1416.5

1460.5

1345

1454.81449.2

1417.01420.4

1401

1446

River Flow H=1446River Flow H=1446


H=1441.7 (⊿h=4.3m)

Older Gravel (Aquifer) ) k= 6.0 x 10-2 cm/sYouger Gravel (Aquifer) k= 1 .2 x 10-1 cm/s

Older Gravel (Aquitard) ) k= 3.0 x 10-3 cm/s

Tr-7Terrace Tr-3 Terrace Tr-1 Terrace Ghorband River

Infiltration 12.6mm/d , L= 2862.5m

Chapter3

Part 2






Figure 3.5.8 Calculated Potential Lines

Figure 3.5.9 Summary of Profile Analysis

1440

1441

1442

1443

1444

1445

1446

1447

1448

1449

1450

1451

1452

1453

1454

1455

1456

1457

1458

1459

1460

2000 2500 3000 3500 4000 4500

Gro

un

dw

ater

Lev

el (E

l., m

)

Distance (m)

Ground

Case 0

Case 1

Case 2

Tr-3Terrace Tr-1Terrace

Ghorband River

Intake point-2

Intake point-1

River flow 1

AssumptionCase 0 - No intake of water

Case 1 - Intake by infiltration gallery at point-1; ⊿h=4.3m

Case 2 - Intake by infiltration gallery at point-2; ⊿h=4.3m

Spring Discharge

Case 0 22.85 m3/d (100%)Case 1 13.19 m3/d (57.7%)

Case 2 21.10 m3/d (92.3%)

River flow 2

River flow 3

Boundary Case 0 Case 1 Case 2

Infiltration 36.09 36.09 36.09

Seepage at Tr-3 Terrace Scarp -22.85 -13.19 -21.10

River Flow 1 -11.49 153.29 122.49

River Flow 2 -1.57 20.89 123.56

River Flow 3 -0.18 2.43 13.56

Infiltrationgallery - -199.50 -274.60

Flow Rate on Boundaries (m3/d/m)



Chapter3

Part 2




3-53

(3) Areal Analysis

(a) Modeling Concept

To estimate drawdown due to groundwater development precisely, it is ideal to apply the

three-dimensional simulation model which expresses water budget and movement of all relevant

aquifers and surface water. However, there are many limitations on available data:

Extent of aquifer distribution under Tr-7 terrace is not clear.

Vertical distribution of aquifer is roughly known only in the investigation area which is a

part of aquifer area.

Artesian condition in depth is confirmed, but its distribution and nature are unknown.

Main groundwater recharge source is irrigation water which comes through many canals

from Ghorband, Panjshir and Salang rivers. Since the irrigation water is also delivered to

other areas out of the aquifer, it is quite difficult to estimate the amount.

A relatively reliable water budget component that could be known is only groundwater

runoff from the aquifer, which can be measured roughly at canals on Tr-1 terrace and

estimated from the existing river discharge data as described above.

Considering these conditions, it is not realistic to create a sophisticated simulation model with three

dimensions and the combination of underground and surface water. Therefore, a kind of average

groundwater flow model which roughly represents estimated groundwater runoff, permeability and

groundwater head distribution is constructed. As for time, only the dry season is targeted.

(b) Model and Method

The method of steady state plane two-dimensional seepage analysis with FEM (Finite Element

Method) is applied for the area shown in Figure 3.5.10. Figure 3.5.11 shows the calculation mesh

and ground elevation given to the model. The permeability is assumed as follows:

Ground surface to 40 m below: k = 5×10-1

cm/s

40m to 80m: k = 1×10-1

cm/s

Chapter3

Part 2






Uniform groundwater recharge

is assumed on terraces except

Tr-1 and the riverbed. The

amount is 5 mm/d for “Case

2011” (see below for the case

detail) and 2.8 mm/d for “Case

Min.” They are determined by

trials to meet the estimated

runoff. For “Case 2011,”

similarity of head contours

between calculated and observed

on January 18, 2012 (Figure

3.1.20) is also considered.

Along the upstream course of

Ghorband and Panjshir rivers,

recharge from river water is

allowed. On the Tr-1 terrace and

riverbed in downstream area,

discharge from aquifer is

allowed if the head exceeds the

ground elevation. The program

for the analysis was devised by a

JWT member.

Plan View Bird’s-eye View (5 times exaggerated vertically)

Figure 3.5.11 Model Mesh and Elevation Contour

The cases shown in Table 3.5.2 are calculated.

(c) Calculation Cases and Calculation Results

Figure 3.5.12 and Figure 3.5.13 show examples of calculated groundwater flow vectors and

contours. Table 3.5.2 summarizes water budget of calculated cases. Figure 3.5.14 and Figure

3.5.15 show calculated drawdown distribution in case of the dry season in 2011 for Phase-1 and

Phase-2 respectively. Figure 3.5.16 and Figure 3.5.17 are the same cases for the severest drought

year.

As for the Phase-1 development, calculated drawdown is smaller than a few centimeters in the

nearby residential area where main springs and wells distribute. Such small drawdown would not

Figure 3.5.10 Extent of Areal Model

Sayad

Charikar



Chapter3

Part 2




3-55

give significant impact to the present groundwater use, though the total discharge from Tr-1 is

calculated to reduce by 10 to 14 %.

As for the Phase-2 development, the drawdown in the Jamshedkhel Settlement is calculated to be 7

cm to 10 cm in maximum in drought years. This order of drawdown would not give significant

impact to well, but might give some to spring discharge, because the discharge is generally

sensitive to head change at the point. The total discharge from Tr-1 is calculated to reduce by 25 to

32%.

The drawdown under Tr-1 would not produce significant land subsidence, because the drawdown

is not so large (a few ten centimeters) and the distributing clay layers are not thick and not so

compressive judging from the their faces (see Figure 2.1.7 and Figure 2.1.8).

Table 3.5.2 Water Budget of Calculated Cases

A B C E=A+B+C

Case 2011 - 5.55 2.17 2.42 10.15

case 2011-1Phase 1Q=1.01m3/s

5.55 2.17 2.42 10.15

case 2011-2Phase 2Q=2.39 m3/s

5.55 2.17 2.42 10.15

Case Min - 3.89 2.50 2.51 8.31

case Min-1Phase 1Q=1.01m3/s

3.89 2.50 2.51 8.31

case Min-2Phase 2Q=2.39 m3/s

3.89 2.50 2.51 8.31

Note:

*3 Observing period : 17 years (1962, 1963, 1965 - 1980, 2009)

*2 Inferred from precipitation data and calculated total discharge. 7.7 m3/s is the secondsmall monthly discharge in 17 years.

Total GWFlow Rate

ProbabilityWater

Development

Stage

Case Name

Case DescriptionRecharge

Infiltrationof IrrigationWater and

Precipitation

FromGhorbandRiver in

the

UpstreamArea

FromPanjshirRiver in

the

UpstreamArea

Total

*1 Inferred minimum discharge of Ghorband River at the confluence with Panjshir Riverbased on observed data at stations located upstream and downstream.

InferredMinimum

≒ 6.3 m3/s

(*1)

About as of2011

≒1/6～1/8(*2)

≒1/17(*3)

RiverbedInf i l tration

Gal l eryTotal

F G H I J=G+H+I L M N=F+J+L+M

Case 2011 -0.81 -4.08 100% -3.58 0.00 -7.66 -1.27 -0.41 -10.15

case 2011-1 -0.81 -3.66 90% -3.01 -1.00 -7.67 -1.25 -0.41 -10.15

case 2011-2 -0.81 -3.08 75% -2.23 -2.37 -7.68 -1.25 -0.41 -10.15

Case Min -0.42 -2.96 100% -3.48 0.00 -6.29 -1.20 -0.41 -8.31

case Min-1 -0.42 -2.55 86% -3.12 -1.00 -6.30 -1.18 -0.41 -8.31

case Min-2 -0.42 -2.01 68% -2.64 -2.35 -6.31 -1.17 -0.41 -8.31

Spring andcanals on

Tr-1

Case Name

Ghorband

Rver in theUpstream

Area

Ghorband River and Riverside

PanjshirRiver and

Riverside

GW Flow-out

Discharge

Total

Chapter3

Part 2






Figure 3.5.12 Calculated Flow Vectors and Head Contours: Case 2011-1

Figure 3.5.13 Calculated Flow Vectors and Head Contours: Case 2011-2



Chapter3

Part 2




3-57

Figure 3.5.14 Calculated Drawdown for Phase 1 (Q=1.01 m3/s): Case 2011-1

Figure 3.5.15 Calculated Drawdown for Phase 2 (Q=2.39 m3/s): Case 2011-2

Chapter3

Part 2






Figure 3.5.16 Calculated Drawdown for Phase 1 (Q=1.01 m3/s): Case Min-1

Figure 3.5.17 Calculated Drawdown for Phase 2 (Q=2.39 m3/s): Case Min-2



Chapter3

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3-59

3.5.3 Influence to Downstream

It is necessary to know the extent of influence of the water intake to the downstream water users. There

are three existing hydropower dam reservoirs in the downstream. There is no significant water use for

irrigation in the downstream except for an extensive irrigation area of about 13,000ha east of Jalalabad

that is fed by Darunta Dam Reservoir.

The proportions of the intake water quantity to observed discharges at the hydrological stations on the

Panjshir and Kabul rivers were examined as shown in Table 3.5.3. The water intake volume of 52.8

MCM is as small as 0.3 to 1.8% of the annual discharge volumes at the downstream stations. It is deemed

that the influence to the downstream water users is very small.

Table 3.5.3 Proportions of Intake Quantity to Observed Discharges at Downstream Stations

Station 1) Catchment

Area (km2) 2) Data Period

3) Minimum

Monthly

Discharge

(m3/s)

4) Mean annual

discharge

Volume

(MCM/year)

5) Proportion

(%) of 2.39

m3/s to 2)

6) Proportion

(%) of 52.8

MCM/year to

3)

Shukhi 10,887 1967 – 1980

2003 - 2010 22.6 2,925.1 10.6 1.8

Naghulu 26,142 1962 - 1978 29.2 3,385.7 8.2 1.6

Dakha 53,775 1962 - 1978 58.9 19,287.1 4.1 0.3

Figure 3.5.18 Schematic Diagram of Kabul River System

3.5.4 Conclusion

Through the above discussions, JWT concludes that the water development potential of the Panjshir Fan

Acquifer is as follows:

1. JWT recommends the “Infiltration Gallery” as the intake facility since it is very economical and

likely to be accepted by the local people.

Omarz

Gulbahar

Gulbahar

Bagi i Lala

Pul-i-Ashawa

Shukhi

Taghab

Tang-i-Gharu

Naghlu

Pul-i-Kama

Dakah (53,775km2)

Panjshir River

Sh

atu

l R

ive

r

Sa

lan

g R

ive

r

Ghorband River Ghorband River

Pa

njs

he

r

Kabul River

Kabul River

Ta

ga

b R

ive

r

La

gh

ma

n R

ive

r

Pa

kis

tan

Afg

ha

nis

tan

2,2

20

km

2

1,310km2

203km2

50

km

2

C: 425km2

D: 413km2

E: 396km2

C: 13km2

D: 25km2

E: 42km2

32

km

2

4,0

40

km

2

39km2

14km2

17

4km

2

316km2

2,0

51

km

2

85

9km

2

1,182km2

9,9

58

km

2

Ku

na

r R

ive

r

6,236km2

11,665km2

Pul-i-Qarghai

2,4

98

km

2

758km2

9,732km2

Maidan River

Loger River

Gulbahar Dam

(proposed site)

Salang Dam

(propsed site)

Naghlu Dam

(26,142km2)

Pa

njs

hir R

ive

r

(10,887km2)

(3,530km2)

(438km2)

Barikab River

14,905km2

River

Baghdara

Dam

(proposed)

Up

pe

r K

un

ar

Riv

er

(Pa

kis

tan)

Sarubi Dam

Darunta Dam

Maripur Dam

LEGEND

: Catchment Area

: River Network

: Hydrological Station

: Existing Reservoir

Intake

Ｋａｂｕｌ

Ｊａｌａｌａｂａｄ

Chapter3

Part 2






2. JWT judges that the total maximum design discharge of 2.39 m3/s of Water PH-1 and PH-2

(corresponding to 52.8 MCM/year) is available at the Panjshir Fan Aquifer.

3. It is deemed that the design discharge water could be taken by the proposed infiltration gallery

without significant influences to the surroundings and the downstream. According to the numerical

simulation, however, the drawdown of the groundwater around the infiltration gallery made by the

full development plan (Phase 1 and Phase 2) might affect the existing water uses to a small extent in

a severe drought year. Therefore, it is strongly recommended that real drawdown be continuously

monitored after the construction of the infiltration gallery, because there are still various unknown

factors such as change of river course and hydraulic conditions of the aquifer.

4. It is recommended that the development be implemented step-wisely in two phases as KMAMP

proposed in order to carefully monitor the environmental impacts, especially, the drawdown of

groundwater.

5. The decision on the implementation of Phase-2 (30.5MCM/year) shall be made only after it is

confirmed that no significant adverse impact is generated in Phase-1.

Documents

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