Hydrographic and 

Sedimentation Survey of 

Kajakai Reservoir, 

Afghanistan

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1608-M

Prepared in cooperation with the 

Ministry of Agriculture and Irrigation, 

Heater and Soil Survey Department of 

Afghanistan under the auspices of 

the United States Agency for 

International Development
Hydrographic and 

Sedimentation Survey of 

Kajakai Reservoir, 

Afghanistan

By DON C. PERKINS and J. K. CULBERTSON

CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA 

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1608-M

Prepared in cooperation with the 

Ministry of Agriculture and Irrigation, 

Heater and Soil Survey Department of 

Afghanistan under the auspices of 

the United States Agency for 

International Development

Sediment deposition in Kajakai Reservoir 

on Helmand River 1953 to 1968, 

determined using underwater 

mapping techniques

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1970
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HIGKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

Library of Congress catalog-card No. 70 607297

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 30 cents (paper cover)
CONTENTS

Page

Abstract _________________________________________________________ Ml

Introduction. _____________________________________________________ 2

Purpose of survey.____________________________________________ 3

Acknowledgments _____________________________________________ 3

Location and description of reservoir________________________________ 3

Hydrographic survey.______________________________________________ 4

Horizontal control.___________________________________________ 14

Vertical control._______________________________________________ 20

Office procedure-___-_________-_________^________________-_________ 26

Sedimentation ____________________________________________________ 27

Future sedimentation._________________________________________ 41

ILLUSTRATIONS

Page 

FIGUBE 1. Sketch map of Afghanistan showing location of Kajakai

Dam on Helmand River___________________________ M2

2. Sketch map of Kajakai Reservoir showing location of

sediment range lines._____________________________ 4

3. Sketch map of Kajakai Reservoir showing azimuth from 

F2X to orientation monument established for 1968 

hydrographic and sedimentation survey______________ 18

4. Photograph of standard navigational sextant__________ 19

5. Sketch map illustrating position fix by sextant_________ 19

6. Photograph of fathometer chart for sediment range line

12-12 cross section______________________________ 20

7. Example of filed notes and office compilation sheet for

determination of position fix by sextant. ____________ 21

8. Sketch map illustrating position fix by 2-transit method, _ 22

9. Example of filed notes and office compilation sheet for

determination of position fix by 2-transit method_____ 23 

10-13. Photographs showing 

10. Transitman directing boat on a given azimuth.. _ 24

11. Boat with fathometer crew beginning sounder

run____________________________________ 24

12. Triangulation transitman at F2X____________ 25

13. Survey crew receiving training in transit operation. _______________________________:._ 25

in
IV CONTENTS

FIGURE 14-24. Cross sections of Kajakai Reservoir Page

14. Sediment range lines 1-1 and 2-2___________ M28

15. Sediment range lines 3-3 and 4-4______________ 29

16. Sediment range lines 5-5 and 6-6____________ 30

17. Sediment range lines 6-7 and 8-8____________ 31

18. Sediment range lines 9-7 and 9-10___________ 32

19. Sediment range lines 11-11 and 12-12________ 33

20. Sediment range lines 13-13 and 14-14________ 34

21. Sediment range lines 14-15, 14-16, and 17-17_ 35

22. Sediment range lines 18-18 and 19-19________ 36

23. Sediment range lines 20-20 and 21-21________ 37

24. Sediment range lines 22-22 and 23-23________ 38

25. Graph showing profile of sediment distribution along

Helmand River channel through Kajakai Reservoir.__ 39 

26-28. Photographs showing 

26. Foerst bed-material sampler in use____________ 40

27. Sediment deposited along river flood plain near

range line 22-22_______________________ 41

28. Flow-duration curve of annual inflow to Kajakai

Reservoir, 1953-65 water years _____________ 42

TABLES

	Page 

TABLE 1. Comparative summary, original and 1968 surveys. _____ M5

2. Capacity table of Kajakai Reservoir, 1968_____________ 5

3. Azimuths of monuments and sediment range lines______ 6

4. Summary of 1968 Kajakai Reservoir reach data________ 10

5. Cross-section area of sediment range lines______________ 13

6. Azimuths to triangulation stations.___________________ 14

7. Particle-size analyses of bed material-___ ______________ 40

8. Summary of annual inflow to Kajakai Reservoir______ 43
CONTRIBUTIONS TO THE HYDROLOGY OF ASIA 

AND OCEANIA

HYDROGRAPHIC AND

SEDIMENTATION SURVEY OF

KAJAKAI RESERVOIR, AFGHANISTAN

By DON C. PERKINS and J. K. CTTLBERTSON

ABSTRACT

A hydrographic and sedimentation survey of Band-e Kajakai (Kajakai 

Reservoir) on the Darya-ye Hirmand (Helmand River) was carried out during 

the period September through December 1968. Underwater mapping techniques 

werer used to determine the reservoir capacity as of 1968. Sediment range lines 

were established and monumented to facilitate future sedimentation surveys. 

Afghanistan engineers and technicians were trained to carry out future reservoir surveys.

Samples were obtained of the reservoir bed and in the river upstream from the 

reservoir. Virtually no sediments coarser than about 0.063 millimeter were 

found on the reservoir bed surface. The median diameter of sands being transported into the reservoir ranged from 0.040 to 0.110 millimeter. The average 

annual rate of sedimentation was 7,800 acre-feet. Assuming an average density 

of 50 pounds per cubic foot (800 kilograms per cubic meter), the estimated 

average sediment inflow to the reservoir was about 8,500,000 tons (7,700,000 

metric tons) per year.

The decrease in capacity at spillway elevation for the period 1953 to 1968 

due to sediment deposition was 7.8 percent, or 117,700 acre-feet. Redefinition of 

several contours above the fill area resulted in an increase in capacity at spillway elevation of 13,600 acre-feet; thus, the net change in capacity was 7.0 percent, or 104,800 acre-feet.

Based on current data and an estimated rate of compaction of deposited sediment, the assumption of no appreciable change in hydrologic conditions in the 

drainage area, the leading edge of the principal delta will reach the irrigation 

outlet in 40-45 years.

It is recommended that a resurvey of sediment range lines be made during the 

period 1973-75.

Ml
M2 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

INTRODUCTION

Storage of water behind Kajakai Dam on the Darya-ye Hirmand 

(Helmand River1 ) (fig. 1) began in January 1953. A reconnaissance 

survey of Band-e Kajakai (Kajakai Reservoir) was made in May 1967 

to observe generally the magnitude and extent of sediment deposition 

that occurred during the first 14 years of storage. Sediment deposition 

appeared to be significant, and recommendations were made that a 

more comprehensive sedimentation survey be carried out.

The Agency for International Development (USAID), an agency 

of the Government of the United States of America, and the Ministry 

of Agriculture and Irrigation (MAI), an agency of the Royal Government of Afghanistan (RGA), signed an agreement to conduct a 

hydrographic and sedimentation survey of Kajakai Reservoir. A survey was carried out during the period September through December 

1968. The results of the survey are presented in this report.

FIGURE 1. Sketch map of Afghanistan showing location of Kajakai Dam on

Helmand River.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M3 

PURPOSE OF SURVEY

The objectives of the survey were (1) to define the current stagecapacity relation, (2) to determine the rate of sedimentation since 

closure in 1953, (3) to establish sediment range lines in order to 

simplify future sedimentation surveys, and (4) to train Afghan 

engineers and technicians in the techniques and procedures used in 

the survey.

ACKNOWLEDGMENTS

Accomplishment of the hydrographic and sedimentation survey of 

Kajaki Reservoir in the relatively short period of time allotted was 

the result of cooperative efforts of several organizations and many 

individuals. Planning and execution of the survey was done by U.S. 

Geological Survey engineers of the Surface Water Research Project, 

NAD, USAID, in cooperation with the Water and Soils Survey Department (WSSD) of MAI. USAID and RGA provided funding. 

The following engineers and technicians worked on the project: 

USAID: A. O. Westfall, Project Chief; D. C. Perkins and J. K. 

Culbertsoii, consultants; Vincent Piro and Dallas 

Childers, Jr., field engineers.

WSSD: Abdul Jadar Haidari, Mirza Mohainmad Mushtaq,

Anwar Lodin, engineers; M. Asif, Najibullah, M.

Omer, Rahmanudin, Wali Mohamadi, Nazar M.,

Abdul Aziz, technicians.

PEACE CORPS: Patrick Molinari, Forrest Garrison, Joseph

Goss, volunteers.

Individual and personal thanks go to Messrs. Jumina Mohammadi, 

President, WSSD; Marion Patten, Gordon V. Potter, Drew Mills, and 

Elonzo B. Grantham, Jr., of USAID; and Governor Safi, President, 

Helmand-Arghandab Valley Authority (HAVA), for their efforts 

and cooperation before and throughout the survey.

LOCATION AND DESCRIPTION OF RESERVOIR

Construction of Kajakai Dam was completed in November 1952, and 

the gates were closed January 1953. The reservoir is about 90 miles (145 

km) upstream from Lashkar Gah on the Helmand River. The dam 

is earth-fill construction and rises 85 meters above the riverbed to a 

crest elevation of 1,050.0 m. Water is stored primarily to furnish 

irrigation water to the lower Helmand River valley. The elevation 

of the irrigation outlet is about 968 m. Future plans for water use 

include installation of hydroelectric units to provide power for the 

Helmand-Arghandab Valley Region (HAVR).
M4 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

Original capacity of the reservoir was 1,495,000 acre-feet at a spillway elevation of 1,033.5 m and a capacity of 2,300,000 acre-feet at elevation 1,045 m. Original zero storage elevation was 965.0 m. The reservoir 

extends about 28 miles (49,000 m thalweg distance) upstream from 

Kajakai Dam. Full-capacity widths of the reservoir vary considerably 

from a minimum of about 200 m in the "narrows'" to about 2,400 m 

at several points. Figure "2 is a sketch map showing the water-surface 

contour at. an elevation of about 1,015 m. Also shown in figure '2 are 

approximate locations of permanent sediment range lines set up as 

a result of the 1968 survey.

HYDROGRAPHIC SURVEY

A comparative summary of the initial capacities, the 1968 capacities, 

change in capacities, and percent change in capacities at 5-m increments of elevation are given in table 1. The 1968 capacity is given in 

table 2.

The hydrographic survey determined locations of current underwater contours as described in the following sections. New contours 

were drawn on prints of the original topographic maps produced by 

the 1953 Fairchild Surveys. Areas within each contour were planimetered and capacities between contours computed as shown in the 

example at the bottom of table 1.

FIGTJBE 2. Sketch map of Kajakai Reservoir showing location of sediment range

lines.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M5 

TABLE 1. Comparative summary, original and 1968 surveys

Elevation (met

1,035

1,033. S 1 ------.----

1,025_. ____________

l'oi5 I'oio

1,005 ___ ________

995

990 ____ _ _ ___

980_______________

970

968

965

Capacity, in thousands 

of acre-feet

1953

___________ 1,587.0

___________ 1,495.0

1 294 0

_ _______ 1,039.0

___ ______ 824. 0

___________ 644.0

48Q 0

___________ 364.0

_ _ ______ 266. 0

___________ 186.0

________ ._ 123. 0

___________ 73.0

___________ 35.0

___________ 13.3

___________ 2.7

__ ________ 0

1968 (

1, 479. 1 

1, 390. 9 

1, 185. 3 

931. 6 

723. 9 

554.3 

422. 0 

321.2 

242.5 

175.0 

117. 7 

70. 8 

34. 2 

10. 5 

1. 2 

0 __.

Change in 

capacity Percent 

n thousands loss in 

af acre-feet capacity 

(15 yr)

107. 9 

104. 8 

108. 7 

107. 4 

100. 1 

89. 7 

67.0 

42. 8 

23. 5 

11. 0 

5. 3 

2. 2 

0. 8 

2. 8 

1. 5

6. 8 

7.0 

8.4 

10. 3 

12. 1 

13. 9 

13. 7 

11.8 

8. 8 

5. 9 

4. 3 

3. 0 

2. 3 

21. 1 

55.6

1 Spillway elevation.

Example of volume computation: 

Given:

A=area of 1,005-m contour = 26,681,000 sq m 

B = area of 1,000-m contour=21,672,000 sq m 

Find:

V= volume, in acre-feet, between elev 1,000 and 1,005 m 

= A+BX 5-Hi,233.49 (cubic meters per acre-foot)

2 

= 26,681,000+ 21,672,OOOX 5n-1,233.49

2 

= 48,353,OOOX 5-n 1,233.49= 98,000 acre-feet

TABLE 2. Capacity of Kajakai Reservoir, 1968, in thousands of acre-feet

Elevation 

(meters)

960................

970..-.-......---.

980... .......... ..

990.__. ...... ..... 

1,000.............

1,010... .........

1,020.. _..........

1.030.............

0

1.2

34.2

117.7 

242.5

422.0

723.9

1. 185. 3

1

2.1

40.7

128.2 

257.1

446.0

763.4

1. 243. 9

2

3.5

47.6

139.2 

272.2

471.3

803.9

1. 302. 7

3

5.3

54.9

150.7

287.9

497. 9

845.4

1. 361. 5

4

7.6

62.6

162. 7 

304.2

525.8

887.9

1. 420. 3

5

10.5

70.8

175.0 

321.2

554.3

931.6

1.479.1 .

6

14.0

79.4

187.7 

339.1

584.3

977.2

7

18.1

88.4

200.9 

358.0

615.9

1, 024. 9

8

0

22.8

97.8

214.4 

378.0

649.7

1, 075. 2

9

0.5

28.2

107.6

228.3 

399.3

685.7

1, 128. 3

Discrepancies in segments of some contours shown on the 1953 topographic map were revealed during the 1968 hydrographic survey. 

They are readily apparent in figures 16-18, and others, which show 

the reservoir bottom in some areas to be lower in 1968 than in 1953, 

although subjected to sediment deposit for many years. Locations of 

some contours above the water surface at the time of the survey were

379-082 O 70 2
M6 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

refined on the basis of levels run from the water surface to sediment 

range-line monuments. As a, result of the refinement in location of 

some contours, capacity in several reaches of the reservoir was found 

to be greater than initially indicated. (See figs. 16-18.)

Sediment range lines were established to aid in future sedimentation 

monitoring surveys. Permanent concrete monuments were located at 

both ends of each range line. These monuments were painted white and 

numbered according to the range lines. Each monument was located 

by triangulation. Azimuths from monument to monument were determined and are given in table 3 for rapid location of range lines in 

future surveys.

TABLE 3. Azimuth of monuments and sediment range lines

[Monument numbers indicated by R denote right-bank location, and L, denote left bank. Right and left 

bank determined by facing downstream]

Monument 

occupied Monument observed

Azimuth of

monument

observed

Remarks

F2X_______ Orientation_____ 0°00' F2X at lookout point near tower.

Orientation point near north end

dam. 

1L1______.___._ 208°33'

2L___________ 158°49'

3L___________ 121°04'

4L_____________ 102°19'

1L2____________ 100°47' On island, under water above

elev 1,020.0. 

6L__-.____.____ 84°07'

9R___.________ 77°17'

11R___________ 81°42'

13L____________ 89°46' SameasFllX.

1L1________ F2X___________ 28°33' Backsight.

Line !-!_______ 75°58'

2L_.___________ 136°21'

3R____________ 54°24'

3L_____________ 96°14'

4R____________ 85°05'

5L.________.___ 86°17'

5R--_-___-___- 61°17'

7R____________ 65°35'

2L_________ F2X___________ 338°49' Do.

1L______.______ 316°22'

Line 2-2_______ 353°58'

3L_________ F2X___________ 301°02' Do.

1L1___.________ 276°14'

1L.____________ 348°30'

Line 3-3_______ 348°32'

2R____________ 316°52'
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M7

TABLE 3. Azimuth of monuments and sediment range lines Continued

[Monument numbers indicated by R denote right-bank location, and L. denote left bank. Right and left 

bank determined by facing downstream]

Monument 

occupied Monument observed

Azimuth of 

monument 

observed

Remarks

4L_________ F2X._________ 282°19' Backsight.

Line 4-4_______ 351°02'

3R_-__________ 314°02'

2R_--_________ 290°47'

lL_-_-_-_____- 265°05'

5L__________-_- 88°11'

5R-_--_-____ 36°35'

6R___.____._ 27°40'

1L___________ 284°54'

5R-__-__ 4L___________ 216°35' Do.

Line 5-5_____ 174°57'

6L_____________ 127°30'

8L_____________ 63°40'

6L_______ 5R---_-------- 307°30' Do.

8L___________ 27°09'

Line 6-6_____ 316°02'

Line 6-7. ____ 5°25' 

9_ _ __ 56°24' 

11R___ ______ 76°37'

8L_________ 6L______________ 207°09' Do.

Line 8-8-_____ 272°22'

7___________ 227°08'

9____-_---_ 6L___________ 236°24' Do.

Line 9-7_______ 285°15'

Line 9-10______ 197°30'

_-_____ lll^S'

_______ 114°26'

5R________ 271°40'

11L________ 10_____________ 307°20' Do.

Line 11-11______ 210°00'

7__________ 318°27'

9___________ 347°38'

12R___________ 61°52'

12R_______ 10_____________ 263°16' Do.

6L___________ 266°30'

Line 12-12._____ 185°02'

7____________ 290°33'

9___________ 294°26'

13L____________ 126°22' Same as FlIX.

13L________ 12R___________ 306°22' Backsight.

Line 13-13__.___ 0° 00' 

11R___________ 302° 55'

5R__________ 285° 46'

7______________ 294° 41'

9____________ 299° 00'

6R__________ 290° 20'

14R___________ 53° 30'

14L________ 13R.__________ 233° 30' Backsight F10X to F11X.

Line 14-14_____ 198° 07' Across lower end of narrows.

Line 14-15-____ 115° 44'

Line 14-16-____ 40°04'

11L____________ 252° 57'
M8 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

TABLE 3. Azimuth of monuments and sediment range lines Continued

[Monuments numbers indicated by R denote right-bank location, and L, denote left bank. Right and left 

bank determined by facing downstream]

Monument 

occupied Monument observed

Azimuth of 

monument 

observed

Remarks

17R______ Orientation_____ 90° 05' 17R monument is at upper end of

	narrows. Orientation is 17L. 

Line 17-17-.. ___ 90° 05' 

21L___________- 29° 01'

18R-_-___-_-__ 31° 04'

19R_--_---_-_- 12° 25'

20R__..______. 13° 25'

20L_________. 38° 58'

18R_.___-__ 17R--__.______ 211° 04' Backsight.

Line 18-18--- 270° 05'

19R______.__ 0°20'

20R____.______ 7°18'

_-_-_____ 28°24'

_______ 13°16'

17L____________ 188°42'

Line 19-19____ 132°00' Do.

-__---___ 15°15'

__.______ 69°31'

_______ 180°20'

-__--___- 192°25'

___---___ 207°58'

__.-_____ 191°02' Do.

Line 20-20 ___ 108°05'

__. ______ 195°15'

._._-__ 74°14'

_________ 166°15'

____-_.__ 187°18'

___-_____ 207°16' Do.

______.__ 254°14'

_________ 199°35'

-__----__ 225°49'

_ _- __ 209°01'

18L__________ 218°23'

Line 21-22_____ 293°04'

22R___________ 39°27'

22R_______ 21L__________ 219°27' Do.

Line 22-22_ _ _ _ _ 146°05' 3,320 m upstream of 21.

23L______ Line 23-23--__. 306°42'
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M9

In order to facilitate future resurveys of Kajakai Reservoir, the 

reservoir has been divided into separate reaches defined by range lines. 

The reaches are delineated by adjacent range lines, or between a range 

line and the end of a definite arm of the reservoir. For instance, that 

portion of the reservoir between the dam and range line 2 2 constitutes a single reach, and that portion between range lines 2-2 and 3-3 

constitutes a second reach. Capacity was determined for each reach. 

The sum of the capacities in all reaches equals the total reservoir 

capacity. Table 4 gives the areas for each contour and the incremental 

capacity in acre-feet between contours for each reach. The incremental 

capacities 'are added to give the total capacity within the reach. Also 

given in this table are coefficients to be applied to resurvey data in 

order to compute changes in capacity. Coefficients vary for each contour interval and between reaches.

The coefficients are empirical and have the dimension acre-feet per 

square meters. The coefficient simply relates the average area between 

contours (contour interval) of the range line cross sections to capacity 

in acre-feet in that reach for the same contour interval. Cross-section 

areas of sediment range lines are given in table 5. For example, the 

capacity in acre-feet between elevation 1,005 and 1,010 in the reach

3-3 to 4-4 may be computed by multiplying the average area in square 

meters between elevations 1,005 and 1,010 of cross sections 3-3 and

4-4 by the coefficient 1.25. Using the data from table 5, and the coefficient from table 4 for the reach 3-3 to 4-4, the capacity in acre-feet is

Capacity= 3930 l'5950X1.25=6? 180 acre-feet.

£i

Therefore, in future surveys the only base data necessary to collect, in 

order to compute a reasonably correct change in storage, will be crosssection areas of each sediment range line.
M10 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

TABLE 4. Summary of 1968 Kajakai Reservoir reach data

Elevation 

(meters)

Area 

(thousands 

of 

sqm)

Capaceity 

(thousands 

of 

ac-ft)

Capac- 

.Area ity 

Coeffl- (thou- (thoucient sands sands 

of of 

sq m) ae-ft)

Reach dam to 2-2

968 - .

970 . ..

975 .--..

980 .......

985

990

995 .......

1,000.. .......

1,005 .

1,010 ..-..

1,015 

1,020 .

1,025 ---..

1,030-.--.--.

1,033.5 .--.

1,035 .

Total..

0

154

367

471

596

762

991

.. 1,280

.. 1,573

.. 1,900

._ 2,276

.- 2,638

.. 3,034

.- 3,529

.. 4,064

..........

0.25 

1.05 

1.70 

2.16 

2.75 

3.55 

4.60 

5.78 

7.04 

8.46 

9.96 

11.50 

13.30 

10.77

4.62

87.49

1.07 

.689 

.676 

.698 

.732 

.782 

.914 

1.05 

1.19 

1.20 

1.32 

1.38 

1.32 

1.50

------

Reach 5 5 to 6-7

968. .

970...........

975 .

980. --.-..

985 .......

990...........

995 .---.-..

I, 000.. .......

1,005... ......

1,010. .....

1,015. ---.

1,020 --.-.

1,025 -..-.

1,030 -.--.

1,033.5 -..

1,035- . . Total.

0

320

1 939

.- 2,170

.. 2,468

.- 2,721

.. 2,912

.. 3,093

.. 3,265

. . 3, 460

.. 3,621

.. 3,938

- 4,194

.. 4,390

0.65 

4.58 

8.30 

9.40 

10.52 

11.42 

12.17 

12.89 

13.63 

14.35 

15.32 

16.48 

12.18 

5.22

147. 11

2.07 

1.13 

1.50 

1.48 

1.56 

1.60 

1.64 

1.67 

1.70 

1.68 

1.71 

1.76 

1.86

Area 

(thouCoeffl- sands 

cient of 

sq m)

Reach 2-2 to 3-3

0 

150 

336 

410 

464 

541 

638 

833 

951 

1,088 

1,220 

1,413 

1,604 

1,715

1,850

0.24 

.98 

1.51 

1.77 

2.04 

2.39 

2.98 

3.62 

4.13 

4.68 

5.33 

6.11 

6.72 

5.06

2.17

49.73

1.39 

.694 

.615 

.584 

.592 

.600 

.693 

.783 

.840 

.821 

.872 

. 825 

.752 

.79

-----

Reach 6- 7 to 9-10

0 

968 

1,394 

1,646 

1,808 

1,940 

2,072 

2,188 

2,310 

2,420 

2,542 

2,669

2,784

1.96 

4.79 

6.16 

7.00 

7.60 

8.13 

8.63 

9.12 

9.59 

10.06 

10.56 

7.74 

3.32

94.66

1.78 

1.41 

1.23 

1.31 

1.34 

1.41 

1.47 

1.50 

1.48 

1.50 

1.54 

1.61

Capacity (thousands 

of 

ac-ft)

Area 

(thouCoeffl- sands 

cient of 

sqm)

Reach 3-3 to 4-4

0 

352 

748 

823 

952 

1,054 

1,188 

1,314 

1,439 

1,610 

1,798 

2,018 

2,320 

2,576

2,802

0.57 

2.23 

3.18 

3.60 

4.07 

4.54 

5.07 

5.58 

6.18 

6.91 

7.73 

8.79 

9.92 

7.63

3.27

79.27

1.06 

1.14 

.896 

.926 

1.02 

1.07 

1.15 

1.20 

1.25 

1.24 

1.31 

1.28 

1.26 

1.34

Reach 8-8 to end

0

2

98 

294 

840 

1,338 

2,016 

3,331

3,649

0.20 

.79 

2.30 

4.41 

6.80 

10.84 

9.90 

4.24

39.48

0.188 

.276 

.548 

.833 

1.08 

1.36 

1.60

Capacity (thousands 

of 

ac-ft)

Coefficient

Reach 4-4 to 5-5

0 

56 

2,128 

2,695 

2,913 

3,094 

3,313 

3,505 

3,687 

3,877 

4,107 

4,413 

4,687 

4,965

5,234

0.09 

4.43 

9.77 

11.37 

12.18 

12. 99 

13.82 

14.58 

15. 33 

16.18 

17.27 

18.44 

19.56 

14.47

6.20 -

186.68 -

0.189 

2.75 

1.75 

1.86 

1.94 

1.99 

2.01 

2.02 

2.01 

1.96 

2.02 

2.07 

2.05 

2.12

Reach 8-8 to 9-7

0 

60 

293 

628 

933 

1,262 

1,787 

2,149 

2,567 

2,850

3,036

0.12 

.71 

1.86 

3.16 

4.45 

6.18 

7.98 

9.56 

10.98 

8.35 

3.58

56.93

0.018 

.499 

1.05 

1.19 

1.10 

1.14 

1.24 

1.35 

1.38 

1.44
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN Mil

TABLE 4. Summary of 1968 Kajakai Reservoir reach data Continued

Elevation 

(meters)

Area CapacCthou- ity 

sands (thouof sands 

sq m) of 

ac-ft)

CapacArea ity 

Coeffl- (thou- (thou- Coefficient sands sands cient 

of of 

sq m) ac-ft)

Reach 9-10 to 11-11

968-----...

970-- 

975--- ...__

980--. 

985-.- . 

990-.- 

995--- 

l,000 _ 

1,005.... ..

1,010... _...

1,015 .

1,020-. 

1,025 

1,030 

1,033.5- 

1,035... .......

Total 

0

477

918 

1,140 

1,305 

1,416 

1,523 

1,614 

1,708 

1,810 

1,918 

2,019

2,125

0.96 

2.83 

4.17 

4.96 

5.52 

5.96 

6.36 

6.73 

7.13 

7.56 

7.98 

5.88 

2.52

68.56

3.51 

.976 

.793 

.895 

.956 

1.01 

1.05 

1.08 

1.11 

1.15 

1.19 

1.21

Reach 14-14 to 14-15

968-. 

970--- -.

975..- ....

980-- 

985. ..........

990.- 

995... ....... .

1,000. 

1,005. .

1,010- 

1,015 .. 

1,020 

1,025 ..

1,030. 

1,033.5-. .__._..

1,035..........

Total...

0 

111 

490 

1,256 

1,507 

1,692 

1,805 

1,908 

2,005

2,106

0.23 

1.22 

3.54 

5.60 

6.49 

7.09 

7.52 

7.93 

5.83 

2.50

47.95

1.23 

.792 

1.76 

1.91 

1.19 

1.18 

1.20 

1.22 

1.27

Reach 11-11 to 12-12

0 

756 

1,179 

1,299 

1,384 

1,440 

1,495 

1,537 

1,581 

1,639 

1,690

1,738

1.53 1.01 

3. 92 . 915 

5.02 1.01 

5. 44 . 978 

5. 72 . 957 

5. 95 . 951 

6. 14 . 948 

6. 32 . 925 

6. 53 . 923 

6. 75 . 922 

4. 86 . 928 

2.08

60.26

Reach 14-15 to 14-16

0 

383

908 

1,004 

1,084 

1,174 

1,272

1,362

0.78 1.95 

2. 62 . 952 

3. 88 . 982 

4. 23 . 975 

4. 58 1. 01 

4.96 1.06 

3.74 1.11 

1.60 .......

26.38

Area 

(thousands 

of 

sqm)

Capacity 

(thousands 

of 

ac-ft)

Coefficient

Reach 12-12 to 13-13

0 

137

726 

864 

985 

1,120 

1,237 

1,326 

1,468 

1,580 

1,733

1,903

0.28 

1.75 

3.22 

3.75 

4.27 

4.78 

5.20 

5.66 

6.18 

6.72 

5.16 

2.21

49.18

1.71

.917 

1.02 

.944 

.961 

1.01 

1.03 

1.05 

1.09 

1.13 

1.24

Reach 14-16 to 17-17

0 

40 

251 

274 

298 

323 

344

371

0.08 

.59 

1.06 

1.16 

1.26 

1.35 

1.01 

.43

6.95

0.601 

.856 

.881 

.891 

.915 

.931

Area Capac- 

(thou- ity 

sands (thou- Coeffiof sands cient 

sq m) of 

ac-ft)

Reach 13-13 to 14-14

0 

170 

973 

1,148 

1,352 

1,596 

1,773 

1,894 

1,983 

2,098

2,223

0.34 

2.19 

4.17 

5.07 

5.98 

6.83 

7.43 

7.86 

8.27 

6.13 

2.63

56.90

0.869 

1.76 

1.41 

1.60 

1.70 

1.63 

1.64 

1.63 

1.64 

1.75

Reach 17-17 to 18-18

0 

22 

810 

1,082 

1,320 

1,538 

1,763

2,050

0.04 

1.69 

3.84 

4.87 

5.79 

6.69 

5.41 

2.32

30.65

1.14 

1.54 

1.71 

1.92 

2.09 

1.49
M12 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

TABLE 4. Summary of 1968 Kajakai Reservoir reach data Continued

Elevation 

(meters)

968..........

970..........

975..........

980--........

985..........

990..........

995..........

1,000.. .......

1,005.........

1,010.........

1,015.........

1,020.........

1,025..........

1,030.........

1,033.5.......

1,035.........

Total..

968..........

870..........

975..........

980..........

985..........

890..........

895. ........

1,000.........

1,005.........

1,010.........

1,015........

1,020........

1,025........

1,030........

1,033.5......

1,035........

Total.

Area Capac- 

(thou- ity 

sands (thou- Coeffiof sands cient 

sq m) of 

ac-ft)

Reach 18-18 to 19-19

0

3. 68 1. 58 

. 1,817

7. 85 1. 70 

. 2,055

8. 91 1. 76 

. 2,342

10. 07 1. 51

. 2,628

11.39 1.85 

. 2,994

9. 20 1. 53

3.94 ......

. 3,490

......... 55.04

Reach 22-22 to 23-23

0

1. 61 8. 27 

796

4. 48 3. 31 

.. 1,416

6. 44 2. 53 

1 7"'0

5. 44 2. 69

2.33 ...... 

.. 2,112

20.30

Area Capac- Area Capac- 

(thou- ity (thou- ity 

sands (thou- Coeffl- sands (thou- Coefflof sands cient of sands cient 

sq m) of sq m) of 

ac-ft) ac-ft)

Beach 19-19 Reach 20-20 to 21-21 

to 20-20

0 0

1 997 34 

10. 25 2. 20 3. 29 1. 16 

3, 059 1, 588 

13.38 2.09 6.69 .956 

3, 542 1, 713 

15.38 2.09 7.19 .954 

4, 055 1, 834 

17.55 2.09 7.65 .928 

4, 603 1, 940 

13.88 2.12 5.73 .936

5.95...... 2.46 ......

5, 176 2, 101

80. 43 33. 08

Reach 23-23 

to end

0 

0.05 .......

25 

10. 53 24. 0 

5,169 

30. 50 22. 8 

9,881 

34. 19 27. 4

14.66 .......

14,221

89.93

Area Capac- 

(thou- ity 

sands (thou- Coefflof sands cient 

sq m) of 

ac-ft)

Reach 21-21 

to 22-22

0 

3.32 

1,638 

16.45 

6,480 

28.19 

7,427 

31.11 

7,921 

23.12

9.91 .

8,377

112. 10

4.43 

4.74 

6.33 

5.90 

6.18
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M13

TABLE 5. Cross-section area of sediment range lines, in square meters

Sediment range lines

Elevation

(meters)

968

970

975

QQA you

985

990

995

1,000

1,005

1,010

1,015

1,020

1,025

1,030

1, 033.5

Total 

1968

2-2

0

233

1,530

2,510

3,100

3,760

4,540

5,040

5,490

5,920

7,080

7,540

8,360

10,050

7,200

72, 350

3-3

0

116

1,310

2,400

2,960

3,120

3,430

3,560

3,750

3,930

4,310

4,710

6,460

7,830

5,610

53,500

4-4

0

961

2,600

4,700

4,800

4,830

5,030

5,290

5,540

5,950

6,830

7,080

7,260

7,910

5,800

74,580

5-5

0

627

6,460

7,400

7,710

8,060

8,470

8,870

9,340

9,660

10, 030

10,600

11, 130

7,870

106,230

6-7 8-8

0

1,640

3,690

5,020

5, 440 0

5, 820 62

5,930 1,080

6, 100 2, 880

6, 400 4, 190

7, 060 5, 300

7, 350 6, 300

7, 590 7, 960

5, 230 6, 190

9-7 9-10 11-11 12-12

0

30 3,

1, 390 4,

2, 860 5,

3,480 5,

4, 230 5,

5, 220 5,

6, 670 5,

7, 560 5,

0

550 0 0

090 2, 720 329

970 5, 560 3, 020

290 5, 780 4, 200

480 6, 060 5, 070

600 6, 180 5, 790

670 6,400 6,120

760 6, 680 6, 290

890 6, 900 6, 760

7,830 6,040 7,120 7,020

7, 920 6, 080 7, 310 7, 340

5,360 4,420 5,250 5,230

67,270 33,960 52,550 58,840 65,960 57,170

13-13

0

795

2,130

2,870

3,090

3,330

3,800

3,990

4,330

4,570

3,100

32,000

Sediment range lines

968

970

975

980

985

990

995

1,000

1,005

1,010

1,015

1,020

1,025

1,030

1,033.5

Total 

1968

14-14

0

358

3,070

3,230

3,690

4,570

5,060

5,330

5,510

3,890

34,708

14-15

0

797

4,250

6,290

6,990

7,240

7,460

5,320

38,350

14-16

0

1,250

1,600

1,690

1,820

1,900

1,390

9,650

17-17

0

720

880

940

1,000

1,060

780

5,380

18-18 19-19

0 0

2, 230 2, 430

4,090 5,120

4, 750 5, 380

5, 030 6, 280

5, 250 7, 060

6, 500 5, 500

27,850 31,770

20-20

0

4,190

7,440

8,440

9,690

7,560

37,320

21-21 22-22

0

1,500 0

6, 550 390

6, 630 2, 270

6, 800 3, 740

4, 690 2, 790

26, 170 9, 190

23-23

0

438

1,340

1,250

3,030

379-082 0-70-3
M14 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA 

HORIZONTAL CONTROL

A topographic map compiled by Fairchild Aerial Surveys, Inc., 

U.S.A., using stereophotogrametric methods was used as the base map. 

The scale of this map was 1 :50,000, with a contour interval of 5 meters. 

The original Fairchild triangulation stations were plotted on the map.

Prior to the 1968 hydrographic survey, the U.S. Bureau of Reclamation of Helmand-Arghaiidab Valley Region (HAVR) recovered and 

placed flags on the Fairchild triangulation stations that were above 

the reservoir level. The bearing of the lines between triangulation stations were available for the 1968 survey. The azimuth of lines as computed from the bearings are given in table 6.

TABLE 6. Azimuths to triangulation stations

[Based on the Fairchild Survey. Positions originate at F2X (at tower observation point) and are carried 

through the triangulation net on the assumed azimuth of 130°00' for the line F2X to F4X. Vertical datum 

is 1,051.79 m below station F2X elev 1,051.79 m. (See fig. 3)]

Station occupied Station observed Azimuth

F1X______________________.__ F2X ________________________ 09°13'14"

F4X _ _ __-_ _ _______ __ 92°25'09"

Cutinpeak_--__ _ __ __ ----- 140°30'36"

Cut in peak __ ___ ___ FIX __ _ - ___ _____-____-- 320°30'36"

F2X____ ------- 344°13'11"

F4X_____ - _ - _ _ 44°30'55"

_____ _---__ - 85°18'12"

________--_- ___________ 130°00'00"

Cut in peak. _ __ ______ _ __ 164°13'11"

FlX_ _ . -_ 189°13'14"

Cut in peak-___ _ _ _ 224°30'55"

-.---_- ----------------- 272°25'09"

_____ __ _______________ 310°00'00"

______-_---___ _--_-----_ 347°49'40"

F5X__ __ -------- 11°49'12"

_______________ -__-__-_ 46°49'39"

____---__-____ _________ 43°53'21"

F5X____ --- _---------___ 104°47'21"

F4X- 167°49'40"

______________ _________ 265°18'12"

F3X____ -_ _ ------- 284°47'21"

F7X_ 21°02'11"

F6X___ - __ - - 144°43'07"

F4X__________________- ______ 191°49'12"

F3X - __ -- - 284°47'21"

F6X_ ________________________ F4X_________-_-______- ______ 226°49'39"

F5X____ ____ __________ __ 324°43'07"

F7X__ -. 01°21'28"

F8X 39°12'59"

F9X ________ _______-__-._ 65°40'51"
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M15

TABLE 6. Azimuths to triangulation stations Continued 

Station occupied Station observed Azimuth

F7X_ ________________________ F17X__ _____________ __ _____ 36°46'01"

F8X_ _ _____________________ 106°17'51"

F9X________ _________________ 137°42'26"

F6X________ _________________ 181°21'28"

F5X _________ _ --_______._- 201°02'11"

F3X____ _____________ _ _____ 223°53'21"

F8X_ ________________________ F7X____--____________- ______ 286°17'51"

F17X_____________ ___________ 01°54'59"

F18X_ ________________ __ .__ 33°39'29"

F10X____ ____________________ 97°19'14"

F11X- - _.__ 124°10'27"

F9X_ _____________ _ ________ 180°13'05"

F6X__ _______________________ 219°12'59"

F7X__ _______ _ _____________ 286°17'51"

F9X_ ________________________ F6X_________ _ _____________ 245°40'51"

F7X -- ___- _ -----__ 317°42'26"

F8X____-______ ______________ 00°13'05"

F11X_ __________________ ___ 84°04'37"

----____________-_____ F18X_ _______________________ 97°50'02"

F10X___ ____ _______________ 139°53'08"

F8X______________. __________ 181°54'59"

F7X__ ______ ___ ____________ 216°46'01"

__________________.___ F9X__ ______ ____ ___________ 264°04'37"

F8X_ ________________ ________ 304°10'27"

F10X_____________ _ _ ____ 53°30'32"

F12X__ _ ___________________ 101°32'40"

___________ ___________ 281°32'40"

_____________ _________ 314°54'02"

F13X___ ___ ________________ 346°17'56"

F14X_ _______________________ 25°21'28"

F10X _ _____________________ F11X____ ____________________ 233°30'32"

F8X__ _________________ _ ___ 277°19'14"

F17X__ ______________________ 319°53'08"

F18X___ _____________________ 340°33'09"

F16X_ _________________ ___ _ 22°57'47"

F13X_ _______________________ 76°40'42"

_______________ ___ __ 134°54'02"

_____ _________________ 233°30'32"

F19X__ _ ___________________ 29°51'45'/

F16X_ _______________________ 124°09'50"

F10X_______ _________________ 160°33'09"

F8X_ ___________ ____ _______ 213°39'29"

F17X_ _______________________ 277°50'02"

F19X__ ______________________ F21X___ _____________________ 66°56'17"

F20X_____ ___________________ 123°33'59'

F16X_ _________ ______________ 171°12'53"

_____________ _________ 209°51'45"
Ml 6 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

TABLE 6. Azimuths to triangulation stations Continued

Station occupied Station observed Azimuth

F16X_ _ __ F19X _ . ___________ 351°12'53"

F20X _ ______ 36°39'02"

F15X __ _ __--_-__ 84°10'25"

F14X__ _. _____ ---_ 112°26'21"

F13X _ 173°20'41"

F10X_______ _________________ 202°57'47"

F18X ____ ____ _____ -__ _ 304°09'50"

F19X_ _______________________ 351°12'53"

F13X-- _ __ F14X _ _ _ _ _ 60°09'19"

F12X___ _____________________ 166°17'56"

F10X _ _ _ _ _ 256°40'42"

F16X_ _______________________ 353°20'41"

F14X_ __ F12X 205°21'28"

F13X_ _______________________ 240°09'19"

F16X . 292°26'21"

F15X__ ___________-____---.__ 16°06'59"

F21X__--____-_______________ F24X_. _____________________ 63°52'50"

F22X. ______________________ 109°59'00"

F20X _ _ _ 175°02'35"

F19X__ ______________________ 246°56'17"

F20X______ __________ F21X _ _ 355°02'35"

F22X _ __ 51°43'08"

F15X ___ _ _ 168°13'12"

F16X _ _ 216°39'02"

F19X_ ______________________ 303°33'59"

F21X_ _______________________ 355°02'35"

______________________ F14X- _ __ ___ ___ 196°06'59"

F16X_ _______________________ 264°10'25"

F20X- _ _ 348° 13' 12"

F22X_____ ___________________ 23°25'51"

______________________ F15X- .__ _____ __ _._ _ 203°26'51"

F20X___ _____________________ 231°43'08"

F21X___ _____________________ 289°59'00"

F24X______ __________________ 341°34'41"

F23X______ __________________ 23°10'03"

_---__--._____________ F25X_ _____ _____ _ ___ 05°09'59"

F23X- _______________________ 68°45'21"

F22X____ ____________________ 161°34'41"

F21X_ _______________________ 243°52'50"

______ ______ ____ 44°07'21"

F23X- ____________________ _ 121°15'21"

F24X__ ____________ __ ______ 185°09'59"

F23X_______ _________________ F22X____ ____________________ 203°10'03"

F24X_ . __ _ 248°45'21"

F25X___ _____________________ 301°15'21"

F27X_ _______________________ 06°06'56"

F23X___ _____________________ 186°06'56"

F25X__ _______ ___ ___ 224°07'21"

F29X _ _ _ _ _ ______ 359°08'39"

F28X___ _____________________ 22°07'33"

_---_- ______ _____ 202°07'33"

F29X__ ______ ________________ 247°42'49"

F31X_ _______________________ 357°43'12"

______ ________________ 37°14'07"
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN" M17

TABLE 6. Azimuths to triangulation stations Continued 

Station occupied Station observed Azimuth

F29X__. _____________________ F31X_____ ___________________ 20°07'57"

F28X_____ ___________________ 67°42'49"

F27X_ ________.-_-.________-- 179°08'39"

F31X_. ______________________ F30X_________. ..___-_----___ 128°47'33*

F28X___. _______.-__._____-__ 177°43'12"

_______. _..._______-._ 200°07'57"

F30X______________. _________ F28X _ _ ________-____--_- 217°14'07"

F31X ________ ___ ___ _ _ 308°47'33"

A new triangulation net was established at the approximate highwater elevation and tied to the Fairchild triangulation net (fig. 3). 

The new triangulation net was necessary in order to establish a horizontal reference system with which to correlate the 1968 survey with the 

Fairchild base map.

The new triangulation station network and the lines, or courses, to 

be sounded were plotted on an overlay of the base map. The azimuths 

of the lines to be sounded were determined from the overlay and recorded for use in the field.

The horizontal location of the boat in which the sonic sounder was 

mounted was determined by a transitman located on shore directing 

the boat operator, by two-way radio, on the predetermined azimuth. 

A standard navigational sextant (fig. -i) was used to fix the position 

of the boat on the line being sounded (fig. 5) .

The fathometer chart was marked by the sextant operator pressing 

the remote control switch mounted on the sextant (fig. 6) .

The notekeeper recorded the angle observed by the sextant operator 

and a fix number on the field notes (fig. 7) . The fix numbers were also 

recorded on the fathometer chart (fig. 6). The distance from shore 

was estimated and recorded for the first and last sextant 'angle 

observed.

An alternate method using two transits to locate the position of the 

boat was used (fig. 8) . The sextant operator assumed the duties of the 

second transitman. The transit was located on shore to observe intersecting angles over the entire length of the line being sounded. It was 

necessary to establish temporary triangulation stations for this purpose 

when the intersecting angles could not be observed over the entire 

length of the line being sounded from the previously established triangulation stations.

Two-way radios were used by the first transitman to direct the boat 

operator along the selected course. The second transitman and notekeeper in the boat were in radio communication ; however, a different 

frequency was used to prevent confusing the commands given by the 

two transit-men, boat operator and fathometer operator-notekeeper.
M18 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

Orientation monument. 

/"Azimuth from F2X 0°00'

Not to scale

FIGURE 3. Sketch map of Kajakai Reservoir showing azimuth from F2X (triangulation station 1953 Fairchild survey) to 'orientation monument established 

for 1968 hydrographic and sedimentation survey.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M19

FIGURE 4. Standard navigational sextant.

KAJAKAI 

RESERVOIR

EXPLANATION

Boat location at time of sextant observation

\Z' \

Reference point on shore observed with 

sextant from boat

Monument on shore at end of range line

FIGURE 5. Sketch map illustrating position fix by sextant.
M20 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

- « c -_t*_^*_ * , * s * e , <* r , » e * ..--- - »e i" : " »-.- - -«--« 

FIGURE 6. Fathometer chart for sediment range line 12-12 cross section.

Coordinating the time of the first and last fix marked on the fathometer chart and the observation of the intersecting angle 'by the second 

transitman was accomplished by the fathometer operator giving the 

command by radio. The intermediate fix marks on the chart were made 

by the fathometer operator on command from the second transitman. 

The intersecting angles observed by the second transitman were transmitted by radio to the notekeeper-fathometer operator to record on 

the field notes (fig. 9).

Figures 10 through 13 are photographs of other phases of fieldwork.

VERTICAL CONTROL

A continuous water-level recorder installed at the outlet tower provided a continuous record of the reservoir level. The water surface was 

determined by levels from selected Fairchild triangulation stations 

and compared with the level recorded at the outlet tower to determine 

the slope throughout the reservoir. The slope of the reservoir water 

surface was determined to be negligible between sediment range line 

21-21 and the tower. Corrections were applied to compensate for watersurface slope upstream from this range line.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M21

00

H

Q)

SP

o

1 -J & a 

o H

-p 

cd o OI-H

1 CO

 H d

 d

Q) rt 

o H

H CO

O <U

0 -ll

PM

-P P! Co cd +^

w !*!

P! Q)

O M

^P PI o5 o>

o <u

o >

H -P

Q)

O Q)

-P 0

PI PI

O 03 O -P

i> PI X 

Q) O -P -H H £ * ^

d

O Q)

0) Vi !-i

1 O ^H O

 H o3 O tQ P -P -P

0)

bO

EH

P

rt ^

P &0

X PI

CD oj

cn

fi

^

fl 3

 H S

J -H

M

OS

ON

 ^

O

8

H

OO

LfN

O

O

H

H

OJ

"^^

O

H

O

H

t0

IfN

H

O

H

OJ ON

^O 00 

H ON 

O ON

H

d

OJ

t?N 1

1 . ~1

j O

<S H

ON VD

LfN LfN

o o

-* 0

H OJ

£

O

0 0

-P o

LfN

LfN H

OO 

LfN

v^

o

00

ON

_#

-*

LfN

00

ON

oo

oo

*

"^^

O

ON

ON

ON 00 OJ

OJ OO LfN

LfN LfN LfN

ON t t 

ON ON ON

oo oo -3-

LfN ^H- LfN

t- t- t~

ON ON ON

i ON ON

0 « K

H LfN LfN

O O O

o 

000

o o

OO LfN t--

\O t~~ VO

OO -^- LT\

R.

^^

LfN

ON 

ON

H

LfN

O

ON

ON

O

H

LfN

oo

ON

t~

0

o

oo

ON

tH 

0

H

d

00

«

1

LfN

OO

LfN

o

LfN

VO

ON

ON

LfN

H

O

H

OJ

ON

0

H

O

H

MD

03

LfN

O

O

H

CO_

"o*

o

0

H

 3

efl

 I

ft

art
FIGUEE 8. Sketch map illu
Lake: Kajakai 

Location: TV No. 2 at Gage: 1018AO

Date: Sept. 20, 1968 

Sheet 12 of 22 sheets

Line 

azimuth

5R to 5L

175 °00'

Fix

1

2

3k

5

6

Azimuth to fix

^0°28'^2°00'

M^°00'

57°00'

70°00'

8^°32'

Distance to/from 

shore 

meters

2

3

Elevation 

at 

fix

meters

1016 .2

998.9975.897^.3975.^

1016.7

Contour locations at proportioned 

distance between sextant fixes

101 5/. 07 1010/.21 10057.3^ looo/.9^

995/-29 990/.33 98 5/.W 980/.53975/.3S975/-5S980/.07 985/-10 990/.51 995/-70

10007.78 1005/.86 10107.92 1015/.99

FIGURE 9. Example of field notes and office compilation sheet for determination of position fix by 2-transit method.
M24 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

FIGURE 10. Transitman directing boat on a given azimuth.

FIGURE 11. Boat with fathometer crew beginning sounder run.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M25

FIGURE 12. Triangulation transitman at F2X.

FIGURE 13. Svirvey crew receiving training in transit operation.
M26 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

OFFICE PROCEDURE

The Fairchild maps were photographically transferred to a matte 

surface stable-base film. An overlay drafted on stable-base film was 

prepared for each map sheet.

The new triangulation net, location of the flags and sounding lines 

were plotted on the overlay. The fix locations on the sounding lines, 

as indicated in the field notes as sextant angles between targets (fig. 7) 

were plotted on the overlay by using a two-arm protractor. This 

method of horizontal positioning is based on the assumption that the 

boat is in line at the time the sextant angles are observed.

Errors in the observed angles or in the plotting of the angles were 

usually apparent when the proportionate distance between plotted fix 

locations were compared with the fix locations indicated on the fathometer chart. Minor variations in the proportionate distances were acceptable and were considered due to minor variations in boat speed.

Compilation of the data recorded on the fathometer chart was 

accomplished in three steps.

Step 1. The chart (fig. 6) was visually inspected to determine if the 

zero setting as indicated on the chart remained in the correct position 

and if the fathometer operator switched to the correct depth range 

without a loss of record and maintained the gain control at the proper 

level. The field notes wTere correlated with the fathometer chart and 

notations made on the chart indicating the reservoir level at the time 

the soundings were obtained, and the date the soundings were made.

Step 2. The depths indicated on the chart were converted to elevations by using a graphical sliding scale placed on the chart in a position to relate the gage height at the time the soundings were made to 

the zero depth as indicated on the chart. The depth indicated by the 

chart record was converted to elevation by the sliding scale.

The elevation at each fix mark and the position of each contour 

elevation to be transferred to the map were noted on the fathometer 

chart.

Step 3. The elevations at each fix and the contour locations at proportionate distances between fixes were recorded on the field note sheet.

A variable scale, or a 10-point divider, was used to determine the 

contour locations at proportionate distances between fixes. The data 

recorded opposite fix 2 (figs. 7, 9), 1015/.07, 1010/.21, 1005/.34, 

1000/.94, indicated that the 1,015-m contour was located 0.07 of the 

distance between fix 1 and fix 2 and the 1,010-, 1,005-, and 1,000-m 

contours were at the proportional distances between fix 1 and fix 2 of 

0.21, 0.34, and 0.94, respectively.

The proportionate distance between fixes, determined from the recorder chart for each contour location, was transferred to the overlay.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M27

Where more definition of the under-water contours was required, additipnal lines to be sounded were plotted on the overlay and the azimuth 

determined.

SEDIMENTATION

One of the objectives of the survey was to establish permanent sediment range lines which could be resurveyed at any later date to determine future rates of sediment deposition. Location of range lines was 

based on probable representativeness of the cross sections to the reach 

upstream and downstream. Cross-section areas of these range lines are 

related to capacity in adjacent reaches. Cross sections of all sediment 

range lines are shown in figures 14 through 24.

Figure 25 shows the relation between the original streambed, or 

thalweg, profile and the 1968 profile, as determined by this survey. 

Locations of sediment range lines are indicated. Kange lines were 

established uplake only to the point where the current and original 

streambed elevations coincided. This point was determined to be at 

about elevation 1,025 m and about 45,000 m thalweg distance from the 

dam.

Depths of deposited material reached a maximum at about range line 

14-16 (fig. 21) where the average depth of sediment in the cross section 

was 18.5 m. The leading edge of the deposition was at cross section 11- 

11 (fig. 19). The most active area of deposition was in the delta area 

formed where the river enters the reservoir. Position of this active 

delta is governed by reservoir elevation and river discharge. The rate 

of movement of the delta becomes more rapid when the i'eservoir 

elevation is low and river discharge is high. During that period of the 

year when river discharge becomes significantly greater than releases, 

the reservoir elevation rises rapidly, and the delta movement into the 

lake slows as more deposition occurs at the higher elevations upstream. 

As the elevation of the reservoir drops, a part of the sediment deposited in the upstream reaches is carried further into the reservoir. 

The two small deltas at elevations 1,010 and 1,015 m (fig. 25) are the 

relatively recent effects of the latter phenomena.

Movement of the leading edge of the deposit, in that reach between 

range lines 12-12 and 14-15, will not advance appreciably until the 

secondary deltas between range lines 19-19 and 21-21 are moved to 

range line 14-15. This may occur rapidly if the water level in the 

reservoir is drawn down to an elevation of 1,005 m or less for 2 or more 

years in succession. However, if the minimum reservior elevation is 

not drawn down below about 1,015 m for a number of years, delta encroachment to the narrows will be slower because the sediments would 

be deposited as bernis in the upstream river channel between range line 

21-21 and some point upstream of where the current profiles coincide.
M28 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

1050

1030

< 1000

i \ i ( i i i i r

1953 survey

 1968 survey

-- Monument and number

J____L J____L

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

en 1020

990

Monument beyond 

limit of illustration

 1953 survey

 1968 survey 

' "-&- Monument and number 

(right bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGUKE 14. Cross sections of sediment range lines 1-1 and 2-2, Kajakai

Reservoir.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M29

gi-

< 1000

 1953 survey

 1968 survey 

i <J)- Monument and number 

(left bank)

SPILLWAY ELEVATION

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

1050 iZ 1010

S 1000

 1953 survey

 1968 survey 

R -(b- Monument and number 

(right bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 15. Cross sections of sediment range lines 3-3 and 4 i, Kajakai

Reservoir.
M30 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

SR'IIIIIII I I I SI

1000

1953 survey

- 1968 survey

*-£&- Monument and number

(right bank) 

I______I______I

0 200 400 600 800 LOGO 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

1040^-

I I I I I I I

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 16. Cross sections of sediment range lines 5-5 and 6-6, Kajakai

Reservoir.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M31

1050

1010

< 1000

i i i i I i r

 1953 survey

 1968 survey 

6 L -A- Monument and number 

(left bank)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

1030 -

< 1000

 1953 survey

 1968 survey 

IL -^- Monument and nui 

(left bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 17. Cross sections of sediment range lines 6-7 and 8-8, Kajakai

Reservoir.
M32 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

1953 survey 

1968 survey 

Monument and r

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE. IN METERS

i r

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 18. Cross sections of sediment range lines 9-7, and 9-10, Kajakai

Reservoir.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M33

1050

1030

tn 1020

< 1000

in 1020

 1953 survey

 1968 survey 

' (D 1 Monument and number 

(right bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

 1953 survey

 1968 survey 

I2R-4). Monument and numbe 

(right bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 19. Cross sections of sediment range lines 11-11 and 12-12, Kajakai

Reservoir.
M34 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

z 1010

"1 T I T

'x-4~~>

 1953 survey

 1968 survey 

L -(fo- Monument and number 

(left bank)

J______I J______I

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

1030 -

tr, 1020

a.

fc

5

z 1010

I 1 I I I T

J ______ I

IELEV. 1075.95)

 1953 survey

 1968 survey 

R -d>- Monument and number 

fright bank)

I ______ I J ____ J

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 20. Cross sections of sediment range lines 13-13 and 14-14, Kajakai

Reservoir.
ELEVATION, IN METERS 
M36 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

1040

1030

1010

< 1000

 1953 survey

- 1968 survey 

L -d>- Monument and numbe 

(left bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

1030


 1020

z 1010

1000

970

T I I

 1953 survey

 1968 survey 

"-{j>- Monument and numbe 

(right bank)

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

RELATIVE DISTANCE, IN METERS

FIGURE 22. Cross sections of sediment range lines 18-18 and 19-19, Kajakai

Reservoir.
ELEVATION, IN METERS 

e- ~ £ °

J___I___I___I I I
M38 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

1010

 1953 survey

 - 1968 survey

'"-&- Monument and numbe

T (right bank)

0 200 400 600 800 1000 0 200 400 600 800 1000 

RELATIVE DISTANCE, IN METERS

FIGURE 24. Cross sections of sediment range lines 22-22 and 23-23, Kajakai

Reservoir.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M39

Spillway elevation 1033.5 meters

 1953 Profile

--- 1968 Profile

10.000 20.000 30.000

THALWEG DISTANCE UPSTREAM OF DAM. IN METERS

FIGURE 25. Profile of sediment distribution along Helmand River channel 

through Kajakai Reservoir.

Samples of the deposited lake-bed material were obtained with a 

Foerst bed-material sampler. The sampler was raised and lowered by 

means of a U.S. B-54 sounding reel powered by a 12-volt power unit. 

Reel, power unit, and sampler were attached to a simple pipe crane 

which was mounted on the boat (fig. 26). Samples were collected 

throughout the reservoir, from the river at the confluence and in the 

river channel upstream of the reservoir. Core samples of the sediment 

deposits in the reservoir were not obtained because of funds and time 

limitations.

Samples of the lake-bed material were not analyzed for particle-size 

distribution other than to determine the percentage passing a 63 micron 

sieve. These samples were virtually all identical in composition, 99.4 

percent limestone clays and silts and 0.6 percent coarser than 63 

micron. Estimated density of these fine-material surface deposits was 

30-50 (Ib per cu ft), or 480-800 (kg per cu m). Apparently, much of 

this material originates from the banks of the reservoir, being sorted 

and washed out of the natural soils by wave action. ,

Samples taken from the area of the river confluence and the river 

channel upstream were analyzed for particle-size distribution by wetsieve method. Results of these analyses are given in table Y.
M40 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

-**

FIGURE 26. Foerst bed-material sampler in use.

TABLE 7. Particle-size analyses of bed-material samples of Helmand River

Percent finer than indicated

size (microns) 

Location of sample

63 125 250 500

Confluence with river at elev 1,015 m______________ 75. 3 98. 6 99. 8 100

Do-_-_____________________________._______ 77. 5 98.8 99.9 100

Dry sample deposited about 1,600 m upstream of 

range line 23-23____________________ 11.6 93.9 99.9 100

River channel at elev 1,026 m___________________ 4.2 63.1 99.2 100

Upstream of sediment range line 23-23, the bed of the river channel 

consists largely of rock and gravel with only minor deposits of sands 

and silts. Virtually all material finer than about 0.5 millimeter is carried in suspension into the upper reaches of the reservoir. During 

periods when the reservoir elevation is at, or above, spillway elevation, 

river discharge is also high, and most of the sands carried in suspension are deposited in the old river flood plain (fig. 27). To date, these 

deposits appear to be relatively insignificant in terms of reducing the 

useful capacity. Measurement of the volumes of sediment deposited in 

the reservoir area upstream from sediment range line 23-23 was not 

undertaken in the 1968 survey. Figure 24 is an illustration of typical 

cross sections in the upper reservoir reaches where berms of fine sand 

and clay are found in the flood-plain areas.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M41

FIGUKE 27. Sediment deposited along river flood plain near range line 22-22.

FUTURE SEDIMENTATION

As shown in table 1, the results of the 1968 survey indicated a loss 

in capacity of 7.0 percent at the spillway elevation 1,033.5 meters. 

Owing to discrepancies found in several original contours, however, 

this indicated loss in capacity cannot be used strictly as a loss due to 

sediment deposition. Refinement of original contours resulted in an 

increase in capacity in those reaches between range lines 5-5 and 13-13 

of 'about 13,600 acre-feet (figs. 16-18). Applying this correction to 

the original capacity of 1,495,000 acre-feet at spillway elevation results 

in a loss due to sediment deposition of 7.8 percent, or a sediment 

deposition of 117,700 acre-feet during the first 15 years of storage. This 

was an average annual loss in capacity below spillway elevation of 

about 7,800 acre-feet per year. Assuming an average sediment density 

of 50 Ib per cu ft, the average annual sediment inflow was about 

8,500,000 tons per year.

A flow-duration curve (fig. 28) based on data given in table 8 shows 

that the average annual inflow to Kajakai Reservoir for the period 

1953-1965 was 5,200,000 acre-feet. Assuming that inflow characteristics 

do not change appreciably over the next 15-year period, it is probable 

that the sediment inflow will average about 8,500,000 tons (7,700,000 

metric tons) per year during that period. Future rate of change in 

capacity, however, may vary considerably if reservoir operation is
M42 CONTRIBUTIONS TO THE HYDROLOGY OF ASIA AND OCEANIA

changed, owing to an increase in rate of release for irrigation or power 

production, or if the timing of releases is changed. Sediment deposits 

will gradually become compacted over the years as more sediment is 

deposited over earlier deposits. Bate of compaction of sediment can 

be estimated only if data are available on size of the deposited material. 

These data are not available and cannot be obtained without core 

samples of the entire depth of deposit.

Samples that were obtained indicate that the greater percentage of 

the deposited material consists of extremely fine material at densities 

of 30-50 pounds per cubic foot (480-800 kg per cu m). These deposits 

will compact under water over the years. Also, if the water level in 

the reservoir were to be lowered to an elevation of 1,005 m, or low^er, 

each year for a number of years, the fine sediments at elevations about 

1,005 m would compact more rapidly because of alternate wetting 

and drying.

To estimate future volumes of sediment deposition based on an 

average annual fill rate of 7,800 acre-feet determined after 15 years 

might be conservative. An experiment to determine reduction in volume due to drying was performed during the survey on material 

sampled from the lake bed. When the samples were thoroughly dried,

99.8

99.5 

99.0

QQ

Q

Q yD

UJ 

UJ Qn

X

UJ

g 80 

Q 70

UJ

< 60

0- 50

UJ

uj 40 

j| 30

Lj- or\

Z 1n

O 

cc. uj 5

2

1.0

0.5 

0.1

\

\

^

V

\

f

V\

X-^^ ~~ --- 

Nv V

3 4 5678 

ANNUAL INFLOW, IN MILLIONS OF ACRE-FEET

10

FIGTJBE 28. Flow-duration curve of annual inflow to Kajakai Reservoir, 1953-65

water years.
SEDIMENTATION IN KAJAKAI RESERVOIR, AFGHANISTAN M43 

TABLE 8. Summary of annual inflow to Kajakai Reservoir

Water year

1953__ __ _______ ___ ______

1954________________________

1955__________--_____-______

1956__ _ _ _ _ __ ____ __._

1957 

1958_ 

1959 _____ ___ __ _____ _

1960___-----__--__-__-______

1961__________-_____________

1962________________________

1963___--____________-______

1964 __ __

1965__ _ __ _ ____________

1966

Helmand River 

near Dehraout 

(acre-feet)

_______ 3,896,000

_______ 4,932,000

_______ 3,575,000

_ ____ 5,295,000

__ ____ 8, 589, 000

___ ___ 4,949,000

_ _ ___ 4,548,000

____ _ 4,411,000

__ ___ 4,591,000

__ __ 2,999, 000

_ __ __ 3,119,000

_______ 4,784,000

_______ 7,171,000

_____ _ 3, 110, 000 .

Tirin River 

at Dehraout 

(acre-feet)

260, 000

591, 000

221, 000

657, 000

470, 000

302, 000

455, 000

324, 000

544, 000

176, 000

182, 000

371, 000

704, 000

Total (acre-feet)

4, 156, 000

5, 523, 000

3, 796, 000

5, 952, 000

9, 059, 000

5, 251, 000

5, 003, 000

4, 735, 000

5, 135, 000

3, 175, 000

3, 301, 000

5, 155, 000

7, 875, 000

the average percent reduction in volume was 53 percent. This value 

was used as a basis for estimating reduction in volume of deposits due 

to alternate wetting and drying.

Based on data that have been presented in this report, an estimated 

rate of compaction, and the assumption that hydrologic conditions in 

the reservoir drainage area do not change appreciably, the principal 

delta front will reach the irrigation outlet (about elev 968 m) in 40-45 

years. At the end of this 40- to 45-year period, it is estimated that the 

reservoir capacity at spillway elevation will be reduced to about 

1,200,000 acre-feet. It is recommended that a resurvey of sediment 

range lines be made at some time during the period 1973-75, especially 

if changes in reservoir operation are made during the next few years.

U.S. GOVERNMENT PRINTING OFFICE-.1970 O 379-082