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DAM-L LS: The Height of Inaccuracy (fwd)
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Date: Fri, 22 Jun 2001 11:01:28 -0700 (PDT)
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Subject: LS: The Height of Inaccuracy
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The Height of Inaccuracy
The Hindu, June 17, 2001
Last year, people in the Narmada valley were ready once again to face the
fury of the river. A week passed but nothing happened .... The villagers
had a better measuring system, says RAVI KUCHIMANCHI.
IT was July 20, 2000. The Narmada was visibly rising, a few inches every
day until it covered the path between Nimghavan and Domkhedi, crossed a
tree and threatened to enter the fields. People prepared for another
showdown with the rising river. So, imagine my surprise when I read the
gauge at Hapeswar after a week and found the water in almost the same
place of about 92 metres. A week passed and another. The water neither
invaded nor retreated in defeat. I started calculating.
The dam was 88m high, about 300m or 400m wide and the over- flowing river
was at 92m. How much water was flowing over? Easy enough - kinetic energy
equals potential energy - we were looking at flows like 10,000 cubic
metres per second ... We thought: at this rate let us see how many days
the Narmada takes to empty itself.
The Narmada carries 23 million acre feet of water every year and we were
less than 40 per cent through a lean monsoon season. Thus at best there
was 15,000 million cubic metres water in it. Draining at 10,000 cubic
metres per second .... the water would get over in just 15 days.
Days passed but the water level did not fall 5 cm. It was the second week
of August and I decided to go to the dam-site to check the water level
there ... is it really 92m? Clearly if the Narmada was flowing so high it
should have all spilled over by now. And so with a flash light, as the
light was fading, on a motor bike past the police check points as we
approached the river, I told myself "it cannot be 92" - the moment of
truth had arrived. It was the time for Satyagraha. There was a government
metre stick half sunk in the river and where it crossed the water, it read
"89.2m" ... not "92.2m".
All of a sudden another thought occurred to me ... it was as if a shadow
were lifted from my eyes ... oh my god the village people were right. They
had a better measuring system than the Government itself. There was nearly
3 metres discrepancy between the Narmada at Hapesar (92m) and the dam
(89.2m). What is more, we had solid proof. Proof that depended on the way
they measure heights compared to the way engineers measured them.
In the past year or two, people told me with certainty that the waters
will enter far more into their villages than the land- acquisition that is
going on. They knew where the flood waters came in 1970 and 1994. "Even
without the dam, the Narmada's waters rose that high. Then with the dam it
will be much more than government figures."
Medha Patkar asked me to carry out an independent survey of levels. I
began to observe this: if in Sikka, Vestha Bhai told me that in 1970 the
flood waters came up to some tree and in Domkhedi if Dedli Behen told me
that it came to some stone, both levels actually tallied when we checked
with the theodolite to within a few centimetres. I began to gain
confidence that the people of the Narmada valley had a very accurate
knowledge of the river. At the Hapeswar temple benchmark that said
105.990m, people from non-government organisations working with the
Government of Gujarat said, "You are cross-checking the heights but this
benchmark here is also the Government's. How do you know that's
right?" They went away laughing, having pondered over the futility of
challenging the Government.
The daggers were drawn at the following positions: All the engineering
knowledge including mine, was to measure heights above mean sea levels
starting from benchmarks. The Narmada villagers, however, measure levels
of the houses from the river or level of the river from their houses and
had internally consistent observations of floods accurate to a few
centimetres. If I started from government bench marks I was just going
around in circles.
So what should I do?
I went to the Narmada Satyagraha.
Waking up to the Narmada everyday, I must have sub-consciously moved from
one system of measurement to another. It suddenly occurred to me that the
river had to be flat - horizontal - because of the dam. Like the water in
a swimming pool or a lake that has the same level everywhere. The Domkhedi
satyagraha was on a 50 km long lake/reservoir created by the dam which was
88m high. Therefore, all I had to do was to measure heights of villages
from the river, like the village people do. There was no need for
benchmarks; in fact they could now be challenged.
We found that the Hapeswar benchmark was only 13.8m above the Narmada
which itself was at 89.2m, as per the metre stick at the dam-site. Which
means the benchmark was at 103m, and not 105.990m as marked. Likewise, the
lowest house in Jalsindhi was at 98.4m, and not at 101.5m as claimed by
NVDA engineers. This explained why waters invaded the Satyagraha at
Jalsindhi in 1999.
In Nimad the dam building engineers working with the CWC predicted, using
the computer where the waters will reach in the worst case of a once in
100-year flood. The NVDA uses this to identify the project affected.
What do the engineers say about floods? "At most 133.95m in Kukra." But
the field office in Rajghat, Kukra, had itself recorded the floods in 1970
at 136.688m, about 3m higher. Moreover, in the last 30 years, the waters
had exceeded three times, the once-in-100-year level that the Government
has calculated. Thus there are serious errors in Government levels of all
the States in the Narmada valley.
What do survey errors mean? Those who will be displaced are not fully
counted. Three metre errors everywhere would mean 20,000 people who will
be affected are left out. The Narmada tribunal stipulates that all those
who will be affected have to be identified and rehabilitated six months
before the building of the dam. Even if the surveys were accurate to the
centimetre, it would mean 60 people not counted, a one millimetre accuracy
will still leave six people out. Such accuracy throughout the Narmada
valley is impossible to achieve using survey instruments which have
intrinsic technical limitations. This shows the project is too big and
internally inconsistent to make tall promises or claims that people
opposing it are scientifically backward and those constructing it are
technologically superior. In fact the civil engineering faculty from our
esteemed universities will agree that the dam is too high and it is
impossible to identify every single affected person six months before
submergence. Leave alone rehabilitate them. Where does this leave the
implementation of the Narmada Tribunal, even in principle?
The facts are even more bleak. The estimate of people who will be
submerged considered by the Narmada Tribunal when it made its final
decision was off by 500 per cent. Had our engineers spent a few months in
the villages consulting people about the floods in 1970 and the geography
of the area, certainly there would have been more accurate estimates. The
dam would have been designed for a much smaller height. Commenting on the
Bargi dam that submerged 162 villages as against an estimated 102
villages, Aravinda once wrote: "Dam builders have not scored high marks in
the Math department".
While we found the survey errors, the Government of Gujarat decided to
repaint the gauges at Hapeswar temple. However, it continues to have the
same errors - only they are more glaring.
Note: Since water is flowing, the backwaters of the Narmada between the
dam and Domkhedi deviate slightly from the horizontal - but this is less
than 1 or 2 cm as the water is flowing very slowly.
* * *
A Nimad villager informed us recently that the engineers have made a +/-3
m stamp. So the Jalsindhi house level will now be 101.500 "+/- 3m"!
Construction began on March 23, 2001 of 3m humps above the 90m dam.
The Narmada Control Authority, admitting that rehabilitation has not been
completed and that there are thousands of families living below 90m with
no alternative land in sight, agreed fo fo for the humps since Gujarat's
engineers said they will be able to keep the waters at 90m levels even if
humps are added. Does the engineers demand make logical sense or the
tribal people's demand - which is stop construction and if need be even
lower the dam height and keep water to a level where rehabilitation is
actually done?
The writer obtained his B.Tech. in Civil Engineering from IIT- Bombay and
Ph.D. in Physics from the University of Maryland, U.S..
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