Failure of a Gate of Sukkur Barrage a Lesson for the Future

Table of contents :
1-01 5000 years of irrigation in Sind
1-02 Every time the Indus changed its course ...
1-03 Every successful dynasty concentrated ...
1-04 Alexander's historians witness ...
1-05 Improvements in irrigation ...
1-06 Changes in the course of the river Indus ....
1-07 Soomras, Sammas and Kalhoras, the master canal builders
1-08 Sind 's population reduced to 45 %
1-09 British make improvements
2. Pre-British canals and their peculiarities
3-0 Fatalist attitude of Sindhis due to Indus
3-01
3-02 Sukkur Barrage takes shape
3-03 Purpose of the Barrage
3-04 Muslim Etlucation--the first ...
3-05 Standard of operation ...
3-06 Collapsing of Gate on 19.12.1982
3-37 What would happen if Sukkur ...
3-08 What would have happened if gate ...
3-09 Difficulties in replacement of gate
4-0 Corrosion and its mechanism
4-01 Corrosion in air
4-02 Corrosion in presence of water
4-03 Corrosion between two different metals
4-04 Corrosion fatigue
4-05 Prevention of Corrosion
4-06 Apparatus used for detecting depth of corrosion
5-0 Various components of gate and their working
5-01 Explanation of figures
6-0 Conclusion, suggestions and recommendation
Figures
The Reading Generation

Citation preview

FAILURE OF A GATE OF SUKKUR BARRAGE. A LESSON FOR THE FUTURE

M. H. PANHWAR 1-01 5000 years of irrigation in Sind In order to understand functions of Sukkur Barrage and from that point the two other barrages namely, Gudu and Kotri, we have to understand the history of irrigation in Sind.

The Indus Valley civilization was an outcome of

irrigation which had started in its rudimentary form at the beginning of Amarian

times ( 3500 B.C.).

As irrigation covered more and more area, the civilization

reached its climax between 2 300 to 1650 B.C. and is presently known as Mohenjo Daro or Harappa Culture in Sind.

1-02 Every time the Indus changed its course irrigation system was destroyed resulting into political upheava l and change of dynasty

This culture abruptly declined as the river Indus changed its course, desert­ ing the central alluvial planes of Sind and swinging too far, either to the east or to the w:::st of the plains, wherefrom water could not reach the irrigated tracts as those were at higher level than the new bed of the river.

The civilization as a

consequence declined and Sind almost turned to a de sert between 1650 to 900 B.C. Archaeologically this period is called Jhukar and Jhangar culture and lately has been assigned the name of the

Declining Indus Culture.

Rough estimate

of

pop u lat ion of Sind is 250,000 souls from 3000 to 2700 B.C. i.e. "Mid Kot Dijjian Times".

It must have reached at least 5 to 6 lacs by the time Mohenjo

Daro

reached its maturity in about 2200 to 2000 B.C.

1-03 Every successful dynasty concentrated on upkeep of irrigation system Information on Sind's history. so far collected rev ea ls that the prosperity of Indus civilization, Rai. Brahma n, Habari. Soomra and Samma dynasties must Sindhological Studies, Summer 1983: 15-32

15

Sindhological Studies

16

have been the consequence of better management of irrigation and agriculture. Likewise the fall of these dynast ies most probably was on account of changes in .

the course of river Indus.

The short-lived prosperous rule of Kalhoras was also

an outcome of well managed irri g ational system and in fact could only be equalled by the British efforts after 50 years of their long struggle with the Indus and its behaviour.

Kalhora dynasty decli ned imm�diately after the change of course of

the riv e r Indus in 1758.

The consequences were dra stic.

1-04 Alexander's historians witn�ss recent destruction of irrigation system by the river Indus It appears that between

950

and 519

B.C. irrigational system was a gain

vived in Sind. The river Indus that time was flowing many miles east sent course and both of its hanks were under cultivation.

re­

of the pre­

The western limit of

irrigated area was probably th e same as the present course of river

Indus. The

area below Sukkur and down to present Hyderabad was known as Brahmanka and its main town was also named as such.

In time it changed to Brahmanabad.

Between 519 B.C. and 400 B.C. Sind was ruled by Achaemenian Persians. The irrigat ion system had been so well managed that Sind (below Multan) paid 36 lac

tankas in gold as tax to the Persian Emperor.

Just before Alexander the

invasion of Sind (325 B.C.), the river Indus had changed its course to with the result that his historians saw the country and Khairpur districts) in ruins.

of Oxycanu s

Gre:it's the east

(Nawabshah

The river had swung too far east in a de pre s si on

wherefrom water could not reach the irrigated land. There are different estimates as to the population and area under cultivation in Sind then.

The figure acc ording to different estimates varies between 5 and 10

lac people and possibly 4 to 7 lac acres were under irrigated agriculture.

1-05 Improvements in irrigation responsible for flourishing trade with Roman Empire

1000 B.C. - 100

A.O.

Mauryans ruled Sind between 323 and 148 B.C. The agriculture and irriga­

tion sy s te m suffered heavily under later Mauryans on account of high burden of t a xes and possibly mismanagement of irrigational works.

ced by Bactrian Greeks (184 to 70 B.C.) and the latter

Mau ryans were repla­

were

rep laced by Scythians

Failure of a Gate of Sukkur Barrage (70 B.C. to 45

A.O.) and Parthians

(46 to 78

A.O.).

17

The irrigation system s�ems

to have been reorganized during that period as Sind was exporting lac-dye, spices,

red pepper, sugar, indigo, cotton linen, wood, rice and sorghum to the Roman Empire through its port of Barbarican (Bhambhore). Nothing is known about irrigation during Kushans

to

(78

175

A.D.) and Sass anians

but irrigation system seems to be well-managed by Vahlikas

to

(283 (356

356 415

to

A.D.) A.D.).

1-06 Changes in the course of the river Indus and decline in irrigation system makes eac;y conquest of Sind by Muhammad Bin Qasim The great improvement in the irrigation system came

onwards and under Rais

(499

to

641

migration

Vahlikas

A.D.), and Brahmans

The river Indus seems to have changed its course just a

from

(641 to 712 A.D.). before 700 A.D. c ausing

of the Kathia tribes of S ind to new area south of Kutch,

to wh i ch they gave their name Kathiawar. The whole irrigated structure of lower Sind seems to have heen destroyed and the area de-p opulated as Arab

troops

under Muhammad Bin Qasim had to march through the area without any opposi­ tion; the forts having been opened without any resistance. Abbasid governors of Sind

(711

to

749

A.D. and

751

to

Under Umayyad and

854

A.D. r espect i vely)

,

irrigation system could not be managed and the destruction caused by change of course of the river around

700

B.C. was not fully recouped resulting in continuous

turmoil, updsings and lawlessness.

It was Habarian

(854

to

local Arab dynasty who man aged irrigation system very well. increa>ed and trade flourished.

1011

A.D.),

The

the

population

The cultivated area under Habarians as worked

out from the various courses of river Indus prevalent during the period may have been

16

lacs and population

25

lacs.

1-Q7 Sl>omras, Sammas and Kalhoras, the master canal builders Under Soomras who ruled from

1011 to 1351,

the river Indus seems to hav�

changei its course at least three times causing destruction of irrigation system and change of their capital but they seem to have quickly re-established system as dynasty did not change for

340

years.

the canal

Soomras were replaced by

Samriias who ruled from 1351to1525 A.O. Some of the canals built hy them sur­

vived for more than three hundred years -..1p to the British times. able to find

sixteen canals of ear ly British period going

J have

back to Samma

been

times. The

18

Sindhologiool Studies

area under cultivation under S amma s may have reached 16 to 17 population to 25 lacs.

Overthrow

lacs and the

of Sammas and their replacement by Ar­

ghoons and Turkham, gave rise to a civil war between new rulers and the rural cultivator community.

Even the Mughal Governor s were not able to rectify the

situati on, thus p o pul ation rducd to 15 lacs in 175 years when Kalhoras rose in 1700 A.D. 1-08 Sind 's population reduced to 45 % by change of course of river a!!d abandoning of millions of acres of irri�:iterl J::md

Kalhoras were master canal builders matched in history only by the British. They improved irrigation system and increased the area under cultivation from

9 to

10 l ac s in 1700 A.D. to about 21 lacs in 1758.

The population too rose from

about 15 lacs to 30 lacs, but this glory was also short - lived.

The river changed

its course in 1758 deser ting its old bed near Hala and adopted the present course. The old course passed fro:n Hala, Oderolal, Nasserpur, Shaikh Bhirkio, Tando Mohammad Khan, Madi, Talhar and Badin to Kori creek.

This situation crea­

ted anti-government uprisings under local Baluchi Chiefs who aftec 25 ,

overthrew Kalhoras and

established their own dynasty.

ye ars

,

Fr om 1772 to

1783

A.D. there was civil war for power between Kalhoras and Baluchi tribes,

who

having won put the Talpurs at the helm of affairs.

1-09 British make improYements to

reduce l abou r on canal maintenance

Talpurs were not able to repair the loss c:rnstd by cha n ge of co u rse of the riv·�r In dus .

The irri gation system was misma naged and the rural population

busy in clearance of canals and cultivation was more than 1.6 persons per acre of lan:nmand area and fertile, were left uncultivated.

(xviii) Only Kharif crop could be grown on these canals. (xix) Many times canals did not have their mouths in the ri ver itself but rather in lakes, and lp from outside and no othez agency of the government of Sind had such facilities.

The facilities were avail­

able with Karachi Ship Yard and Engineering Works and Pakistan Navy.

They

were very kind to come to rescue, and for which people owe them thanks.

Sind

also must express its gratefulness to Mr. H.M. Dahar, who showed all qualities of an able engineer and leader during these gloomy days. It is worthwhile recalling here that for construction used floating dredgers,

25

of barra,se, they had

ton and I 0 ton floating electric cranes, floating pipe

iines, barge pontoons, floating pile drivers and all sort of equipment for working No snch equipment was needed for maintenance and the

on and under water.

irrigation department does not have a single piece of floating equipment today to carry out even the painting of g'.ltcs.

This handicap paralyzed the

whole

department, when the gate collapsed.

4-0 4-!H

Corrosion and its mechanism Corrosion in air

Corrosion is destruction of metal by electro-chemica I or simple action.

Steel is stronger than iron

iron has no carbon.

as

it has some amount of carbon.

Wrought iron due to reaction with atmospheric

chemical Wrought oxygen,

Failure of a Gate of Sukkur Barrage

27

oxidizes forming rust, but in steels carbon turns into carbonate oxide.

and iron into

Since carbon is present

Thus the corrosion in steels is much quicker.

uniformly throughout the section of steel, corrosion attacks the intercry�talline boundari es and p it formation is the result. Corrosion needs moisture

and oxygen

both of which ar� present in atmosphere. Corrosion in presence of water

4-02

If the metal is not in touch with water, initial corrosion or rust formation forms a protective layer and further corrosion i s retarded though not altogether.

stopped

In watt:r rate of corrosion is high but in running water this is further

accelerated due to increased contact of dissolved oxygen.

At high temperatun.:s

rate of corrosion increases i.e. it would he foster in hot summers of Sind than in winters.

Continuous splashing of water on steel allows both atmosphere

dissolved oxygen to further accelerate corrosion. dency to dissolve.

and

The rust so form ed has a ten­

The barrage waters at Gudu, Sukkur and Kotri contain hy·

drogen sulphide. formed due to decay of vegetative material in suspension of stag­ nant or slow flowing waters

specially

in

winters.

Hydrogen sulphide hasten s

corrosion by formation of iron sulphates and sulphides

soluble in

water.

If

water was stagnant a balance would be achieved and no more sulphides or sul­ phate corrosion would o ccur but in moving water attack is sulphates and sulphides

get washed

off.

Then

there

continuous as iron

are anaerobic

bacteria,

which break sulphates in water and soil and help to increase corrosion.

4-03

Corrosion between two different metals If two metals of d ifferent chemical compositions are in contact in presence

of water or soil, there is established electropotential or electric current between them an