Title: Fwd: [riverlink] Digest Number
559
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Date: 31 Aug 2005 18:52:07 -0000
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: [riverlink] Digest Number 559
Reply-To: [EMAIL PROTECTED]
Topics in this digest:
1. Re: National Water Grid is a
Disaster
From:
"S.G. Vombatkere"
<[EMAIL PROTECTED]>
4.
Bogibeel model study inadequate to gauge bridge impact on
river
From:
"River Basin Friends\(NE\)"
<[EMAIL PROTECTED]>
5.
Thousands lose homes and assets
From:
[EMAIL PROTECTED]
________________________________________________________________________
________________________________________________________________________
Message: 1
Date: Tue, 30 Aug 2005 10:08:51 +0530
From: "S.G. Vombatkere"
<[EMAIL PROTECTED]>
Subject: Re: National Water Grid is a Disaster
30.8.2005
Friends,
# Proponents of ILR go on as if the contra arguments never existed!
That is the power of corporate interests speaking.
# The National Water Policy 2002 says one or two things that would do
with highlighting. They are:
1. NWP 2002 states in its Conclusion
paragraphs, "Success of NWP depends upon national consensus and
commitment to underlying principles and objectives". But NWP
fails to define at any place what are its underlying principles and
has displayed no transparency in drafting NWP to justify talking about
national consensus. Indeed, the draft NWP 2002 was prepared in
1998 and kept secret until it was placed before a "grateful"
public in 2002 in its present form. The deepest underlying principle,
to my mind, is that of the Constitution, and this NWP is deeply
flawed.
2. NWP 2002 states that there is "an urgent need of paradigm
shift in emphasis in management". On 01 April 2002, at the
National Water Resources Council, Prime Minister Vajpayee declared
that the nation's water problems can be tackled only if we "catch
every drop of water where it falls", and made no mention whatever
of ILR. But on 15 August 2002, President Kalam spoke about the
inevitability of ILR in order to solve the annual problem of flood and
drought by taking surplus flood water to water-deficit drought areas.
Perhaps this was the gift of the paradigm shift.
3. NWP 2002 states that reclamation of waterlogged and saline affected
lands should be carried out. While this is not really in the realm of
water policy, yet, having mentioned it, the drafters of NWP 2002 have
never bothered to note that waterlogging and saline-degradation of
land (to be reclaimed) is due to human (heavy engineering)
interference with the natural drainage of the land. Roads and railways
almost always interfere with natural drainage and cross-drainage is
always, therefore, a part and parcel of road and railway engineering
works. But this is only to preserve the safety and operational aspects
of the road or railway, not to restore the natural drainage. All
canals also interfere with natural drainage and embankments along
rivers are meant to protect areas from flood but end up as the prime
cause for the disaster of standing water. All these combined, are the
cause of waterlogging and saline-degradation.
Mumbai's disaster in July 2005 was due to
interfering with natural drainage. It is not relevant whether slums or
highrise buildings have blocked waterways; what is relevant is the
blindness-cum-greed of engineers (at some level) and administrators
over the years that has allowed waterways to get blocked in Mumbai. It
is unfortunate that very heavy rain occurring at high tide
precipitated the disaster, which however,was merely waiting to
happen.
# We need to keep on repeating our arguments against ILR and speaking
about it in as many fora that we can.
Sudhir Vombatkere
Message: 4
Date: Mon, 29 Aug 2005 15:01:03 +0100 (BST)
From: "River Basin Friends\(NE\)"
<[EMAIL PROTECTED]>
Subject: Bogibeel model study inadequate to gauge bridge impact on
river
Dear friends, People been taking sense these years, now The Govt
of Assam has started let us see what comes up.The local agitation is
up on the issue.
regards
ravi
Bogibeel model study inadequate to gauge bridge impact on
river
GUWAHATI, Aug 28 The model study conducted on the
Brahmaputra concerning the Bogibeel bridge over it was restricted only
to determine the parameter of the structures of the bridge. It
was not connected with the behaviour of the silt-laden water of the
river in the upstream and downstream of the bridge, said State
Government sources here.
It needs mention that Dibrugarh town is located at the upstream of the
bridge, while the historic Majuli island States centre of
Vaishnavite culture is located in its downstream.
According to sources, the Irrigation Research Laboratory (IRL),
Roorkee, undertook the model study for the rail-cum-road bridge. The
total length covered by the study is 16 kmnine kilometre upstream
and seven kilometre downstream of the bridge centre line. The centre
line of the bridge was along its length.
The engineers of the State Water Resources Department, who were
witness to the re-running of the model about two months back, were of
the opinion that the length of the model study was too short to
determine any adverse impact of the bridge on the flow of the river
and thus on its banks downstream. There were also inadequacies
concerning the upstream impact of the bridge on the river, they
observed.
They therefore, suggested that the model study should be continued for
further downstream and upstream to determine flood and erosion effects
of the river, particularly on its south bank, said the sources.
The model was run with the proposed 4.25-km-long bridge structure and
its approach roads on both the banks, for two conditions with three
discharges 25,000 cubic metres per second (cumecs), 45,000 cumecs
and 73,000 cumecs. The second condition was without the bridge, said
the sources. The officials of the Railways, the Brahmaputra Board and
the IRL were also present during the running of the model, the sources
said.
According to reports, the model was run with clear water and the true
picture of the silt-laden water was not there. This is significant in
view of the fact that the Brahmaputra is one of the major
silt-carrying rivers of the world.
At 6.2 km downstream, with discharge of 45,000 cumecs, the channel
shifted towards south bank with a depth of two metres to five metres
from the bridge centre line to 800 metres. This was suggestive of the
river causing erosion on the south bank up to about one kilometre
downstream of the bridge centre line.
At 4.5 km, downstream, with the same discharge rate, aggradations at
the rate of two metres of silt at 1,600 metres to 2,800 metres were
observed. On the other hand, with the same rate of discharge,
degradation activities of the river between 3,200 metres and 7,800
metres were observed.
The same rate of discharge, with the structures on both the sides,
resulted in increased velocity on the above downstream sections. It is
apprehended that the velocity will continue further downstream of the
bridge beyond 6.2 kms. But due to lack of the model length beyond
that, this could not be assessed, nor could it be assessed as to where
the river would attain its normal velocity, the sources said.
With the discharge rate of 73,000 cumecs, the channel of the river
maintained almost the same depth of three metres on the south bank
with increased velocity on the unprotected portion of the bank at 6.2
km downstream of the bridge centre line. The phenomenon is likely to
continue further downstream. Moreover, at this rate of discharge, the
river channel had shown shifting characteristics from 800 metres to
6,800 metres.
Basing on these, sources said that there would be more pressure on the
south bank embankment in those areas and hence there was every
likelihood of both the bank and embankment there coming under the grip
of erosion.
At 4.5 kms downstream of the bridge centre line, with the same rate of
73,000 cumecs discharge rate, the river channel had degradation
characteristics and because of this, chars are likely to be removed
and deposited beyond 6.2 kms downstream of the bridge centre line.
The velocity distance curves for both discharges showed increased
velocity with the proposed structures beyond 6.2 kms downstream of the
bridge centre line with more deposits on the downstream and formation
of new channels attacking banks and thereby resulting in fanning out
of the river, said the reports.
Further, the sources said that as the bridge would constrict 58 per
cent of the natural width of the river at the proposed location, there
would be huge upstream afflux of over two metres in high flood season.
This afflux will reach up to about 10 kms to 12 kms upstream of the
bridge centre line as per the calculations of the Railways, the
executing agency of the bridge. Significantly, the location of
Dibrugarh town is within this reach on the south bank.
This will necessitate raising and strengthening of the embankment
system of the Brahmaputra and its tributaries falling within the
afflux territory. Moreover, due to gradual dumping of silts, there
will also be another factor of fanning out of the Brahmaputra in this
afflux zone. This will jeopardise the existing embankments on both
banks and also the embankments of the outfalling tributaries. The
tributaries like the Moridhal, Burhidihing and the Dibrugarh Town
Drainage Channel will not be able to discharge their own flow because
of the rise in the Brahmaputra water level in their respective
mouths.
As a result, these tributaries will remain constantly in spate during
the rainy season. There may also be failures in the tributary
embankment systems.
All these hence make a comparative study imperative to determine which
will be more economic to give physical protection against the
phenomena of fanning out of the Brahmaputra and its tributaries
remaining always in spate during the rainy season or to increase the
length of the bridge. They also maintained that in no case the impact
of the bridge on Majuli island should be left unassessed.
http://www.assamtribune.com
River Basin Friends
AKAJAN
District-Dhemaji.787059.
Assam. India
E [EMAIL PROTECTED]
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