बाढ़ और तटकटाव से माजुल वीप का तर...
Transcript of बाढ़ और तटकटाव से माजुल वीप का तर...
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बाढ़ और तटकटाव से माजुल� �वीप का ��तर�ण
Protection of Majuli Island from Floods and Erosion
��मपु� बोड�
Guwahati
Brahmaputra Board
May 2012
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Protection of Majuli Island from floods and erosion –
Measures, Outcome and Plan ahead
1.0 Introduction
The River Brahmaputra divides into two channels – the northern
Kherkutia channel and the southern Brahmaputra channel between
Dibrugarh and Lakhimpur Districts and both the channels join again
about 85 km downstream at Ukhalchuk - forming Majuli, the largest
inhabited river Island in the world. The width (in North- South direction)
of island varies between 10 Km to 15Km.
The Majuli Island is a part of Majuli Revenue Circle. As per the revenue
records, the area of Majuli Revenue Circle in the year 1950 was
1245.12 sq-km. It included entire reach of Brahmaputra water body
up to left bank along Sibsagar, Jorhat and Golaghat Districts. But as
per Survey of India map, the area of Majuli Island was only 733.79 sq-
km in the year 1914.
The Majuli Island is an administrative Sub-division under Jorhat District.
The Island represents a colorful rainbow of cultural integration with 70
% of its population belonging to tribal communities such as Mishing,
Deori, Kachari and Koch Rajbongshi. It has a population of 1.68 lakh
as per 2011 census.
Majuli Island has been under serious attack by the mighty
Brahmaputra. Loss of land mass on account of erosion of
Brahmaputra River right bank has been regular feature for Majuli
Island.
Erosion at Bengen-Ati, Majuli
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On receipt of request of the Government of Assam in November 1999,
Brahmaputra Board prepared a Scheme for ‘Protection of Majuli
Island from Floods and Erosion’ at the estimated cost of ` 86.56 crore,
based upon the recommendations of the Master Plan of
Brahmaputra River, prepared earlier by Brahmaputra Board. The
scheme was proposed to be implemented in three phases – Phase-I,
Phase-II and Phase-III – as per break-up given below-
Sl.No. Phase Amount
(in ` in crore)
1 Phase-I 41.28
2 Phase-II 18.28
3 Phase-III 27.00
Total 86.56
The above scheme was submitted to the Central Water Commission
(CWC) by Brahmaputra Board during August, 2000 for examination.
The scheme was examined in the River Management (RM) Wing of
CWC and recommended to Ministry of Water Resources (MoWR),
Government of India for acceptance, at the estimated cost of ` 86.56
crore, through letter No: 59/Majuli Island/FM-11/95/354 dated 25th
August 2003.
2.0 Execution of Protection Works
2.1 Immediate Measures
Massive land erosion started in Majuli during the monsoon in the year
2003. A Central Expert Team headed by Director, Flood
Management, Central Water Commission visited vulnerable sites of
Majuli Island in the month of June 2003 and recommended certain
immediate measures. Brahmaputra Board formulated a scheme at
the estimated cost of ` 6.22 crore for undertaking immediate
measures, based upon recommendations of the Central Expert Team.
Execution of works started in January, 2004 and completed in
February, 2005 at the expenditure of ` 5.92 crore.
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2.1.2 Important works executed under ‘Immediate
Measures’
Following are the main works carried out under ‘Immediate
Measures’-
(a) Closing of 20 breaches – 16 on Malual-Malapindha Dyke and PWD Road and 4 on Pahumora-Garmur-Jengrai-Haldibari (PGJH)
road,
(b) Raising and Strengthening of 5.55 km long embankment from Kamalabarighat to Kharkharijan and
(c) Casting and laying of permeable RCC porcupine screens / spurs / dampeners at various locations.
Protection works carried out by Brahmaputra Board under
‘Immediate Protection Measures’ are shown in the Plate-1.
Breach closure work on PGJH dyke
2.2 Implementation of Phase-I
The ‘Administrative Approval and Expenditure Sanction’ to the
Scheme titled ‘Protection of Majuli Island from Floods and Erosion’ (of
total estimated cost of ` 86.56 crore) for estimated cost of ` 41.28
crore was communicated by Ministry of Water Resources (Indus Wing)
through letter No: 31/14/2003-IT/141-152 dated 28th January 2005. The
estimate was subsequently revised to ` 56.07 crore. The works under
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Phase-I were taken up by Brahmaputra Board in March 2005 and
completed in April 2011 at the cost of ` 53.40 crore.
2.2.2 Important works executed under ‘Phase-I’
Following are the main works carried out under ‘Phase-I’ –
(a) Plugging / Closure of 3 breaches on Pahumora-Garmur-Jengrai-Haldibari (PGJH) road,
(b) Raising and strengthening of 90.70 km of embankment from Molual to Balichapori, Bokora to Kamalabari, Kharkharijan to
Tekeliphuta and Mili Tiniali to Jengrai,
(c) Casting and laying RCC porcupine screens / spurs / dampeners on northern and southern sides of Majuli Island and
(d) Construction and Repair of nose portion of land spurs at Sonowal Kachari and Kandulimari
Raising and Strengthening of Embankment
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2.2.3 Performance
On execution of works under Phase-I, erosion got arrested
substantially in the severely affected reaches of Sonowal Kachari,
Salmara, Dakhinpat, Kamalabari, Bhakat-Chapori, Kordoiguri, Malual
and Ukhalchuk along the Brahmaputra bank. Similarly, anti-erosion
measures undertaken by Brahmaputra Board proved very effective in
checking erosion along Kherkutia-Subansiri bank at Jengrai, Chelek-
Pathali and Natun Chapori area. The villagers who deserted their
villages at Salmara and Kordoiguri earlier returned back to their
homes on improvement in situation. Anti-erosion / Protection works
executed by Brahmaputra Board under ‘Phase-I’ are shown in the
Plate-2.
2.3 Emergent Works on Recommendations of Standing
Committee of Experts on Majuli
Unprecedented floods occurred during the monsoon of the year
2007. Massive land erosion took place in the reach from Katonobari to
Sonowal Kachari in Upper Majuli, in Dakhinpat-Salmara-Kamalabari
(in Middle Majuli) and Birinabari-Ukhalchuk reach (in Lower Majuli).
The land erosion was virtually unmanageable particularly in Begen-Ati
and Sumoimari reach.
After the devastating floods in the year 2007, Ministry of Water
Resources constituted a Standing Committee of Experts on Majuli
under the Chairmanship of Member (River Management), Central
Water Commission through Office Memorandum No: 11013/6/2007-
B&B/2002-70 dated 25th October 2007 with the following ‘Terms of
Reference’ –
(a) The Standing Committee of Experts will meet and visit Majuli Island at least once in a period of 4-6 months,
(b) The Committee shall review the work executed by the Board for protection of Majuli Island,
(c) The Committee shall suggest suitable measures for protection of Majuli Island,
(d) Brahmaputra Board shall make all necessary arrangements for visit of the team to the site,
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(e) The Committee shall submit the report to the MoWR within 15 days of the visit to the Majuli Island and
(f) The TA/DA in respect of the officials working in Central and State Government will be borne by their respective Ministry /
department.
The committee made its 1st visit of the Island in January 2008 and
recommended certain emergent measures to be undertaken by
Brahmaputra Board prior to onset of monsoon of the year 2008. An
estimate for an amount of ` 4.99 crore was formulated by
Brahmaputra Board.
So far, there have been 7 visits of the island by Standing Committee of
Experts on Majuli Island.
7th visit of Standing Committee of Experts on Majuli Island under the
Chairmanship of Sri S.P. Kakran, Member(RM), CWC
2.3.1 Particulars on Execution of Emergent Works
The ‘Emergent Works’, basically involved construction and laying of
RCC porcupine screens / dampeners at the following vulnerable
locations -
(a) Bhogpur area , downstream of Sumoimari check bund,
(b) Downstream of Kharkharijan in Begen-ati,
(c) Kamalabari reach,
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(d) Bhakatchapori–Pakhimuri and
(e) Bessamara and Dakhinpat reaches
All works planned under the estimate were completed satisfactorily
by September 2008 at the total cost of ` 4.62 crore.
Protection works carried out by Brahmaputra Board under ‘Emergent
Protection Measures’ are shown in the Plate-3.
2.4 Implementation of Phase-II and Phase-III
The estimate / proposal for ‘Protection of Majuli Island from Floods
and Erosion under Phase-II & Phase-III’ was placed before the 110th
meeting of the Advisory Committee for consideration of techno-
economic viability of Irrigation, Flood Control and Multipurpose
Project Proposals, held on 20th July 2011. The Project Appraisal
Organization, Central Water Commission communicated
acceptance of the Advisory Committee to the proposal for the
estimated cost of ` 115.99 crore at the Price Level of the year 2010
through letters No: 16/27/2011-PA(N)/1391-1424 dated 5th August 2011
and No: 16/27/2011-PA(N)/1520-1553 dated 23rd August 2011.
Effectiveness of RCC Porcupines in inducing Siltation
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2.4.1 Status of execution of protection works for Majuli
Island under ‘Phase-II’ and ‘Phase-III’
All works under Phase-II & Phase-III are targeted for completion by
March, 2014. The current status (up to March, 2012) on progress of
works is tabulated below-
Sl.
No. Works planned
Progress in
%age upto
May 2012
Remarks
1. Construction of 5
Boulder Spurs with geo-
bags below Lowest
Water Level (LWL)
39.35 Work is in progress.
2. Casting & Laying of RCC
Porcupines
(1,27,396 porcupines)
72.14 Work is in progress.
3. Bank revetment with
boulders and geo-bags
at 4 (four) locations for a
total length of 5190 m
NIT was floated for
procurement of geo-
bags on 14th February
2012.
4. Bank Stabilization at
PGJH dyke by use of
sand filled geo-mattress
in a length of 3095m
Proposed to be taken
up in XII Plan.
5. Bank revetment at
Jengrai
Tendering is under
process.
6. Raised Platform at 5
locations
One Raised Platform
constructed. Placing
of ‘Work Orders’ for 3
is under process. Land
Acquisition for one is
in process.
7. Pilot Channel- 2 KM Requirement is to be
assessed on
withdrawal of next
monsoon.
8. Construction of Check
bunds at Sonowal
Kachari and Kandulimari
NIT was floated on 9th
March 2012.
The cumulative expenditure incurred on protection works of Majuli
Island under Phase-II & Phase-III upto March, 2012 is ` 49.86 crore.
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2.42 Performance of protection works executed under
Phase-II & Phase-III
The anti-erosion works carried out by Brahmaputra Board so far have
yielded positive results. It may be stated that in the year 2007 the
Sumoimari channel of Brahmaputra river, flowing along southern bank
of Majuli Island from Dakhinpat to Kamalabari for an approximate
length of 25 Km, carried a considerable discharge of Brahmaputra
(40%-45% of total discharge of Brahmaputra). Use of RCC porcupine
screens in Aphalamukh-Dakhinpat area i.e. at the mouth of the
Sumoimari channel induced heavy siltation, as a result, gradually, flow
in the channel got reduced substantially.
Similarly, judicious laying of porcupine screens in the upstream at
Tekeliphuta and downstream areas encouraged heavy siltation. As a
result of above, the entire upper Majuli reach of Brahmaputra has
seen no erosion during the monsoons of the years 2009 and 2010. This
shows that the anti-erosion works carried out by Brahmaputra Board
have brought about far reaching consequences and changes in the
river morphology and thereby these have considerable favourable
impacts in river regime.
Protection works undertaken by Brahmaputra Board till March 2012
under ‘Phase-II & Phase-III’ are shown in the Plate-4.
Land reclaimed at Dakhinpat area
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3. Abstract of Expenditure incurred by Brahmaputra Board on protection of Majuli Island
Estimated Cost, Actual Expenditure incurred and status up to May’12
of the works executed by Brahmaputra Board at various stages since
the year 2004 are tabulated hereunder-
Entire works executed by Brahmaputra Board for protection of Majuli
Island till March 2012 at various stages are shown in the Plate-5.
Sl.
No.
Description Estimated
Cost
(` in crore)
Actual
Expenditure
(` in crore)
Remarks
1 Immediate
Measures
(Year 2004-
2005)
6.22 5.92 Completed
2 Phase- I
(Years 2005-
2011)
56.07 53.40 Completed
3 Emergent
Measures
(Year 2008)
4.99 4.62 Completed
4 Phase-II &
Phase-III (Since
2011)
115.99 49.86 Targeted to be
completed by
March 2014
Total 183.27 113.80
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4. Overall Achievement / Reclamation of Land Mass of Majuli Island
It may be worthwhile to mention that during the period from the year
1963 to the year 2004, there has been, year after year, loss of land
mass of Majuli Island. Brahmaputra Board took up protection of Majuli
Island from floods and erosion in January 2004. Since then no loss of
land mass of Majuli island has occurred. Erosion / Reclamation of land
mass of Majuli Island during the years from 2004 to 2011 is tabulated
below-
It is observed from the above that the total area of the land mass of
Majuli Main Island (assessed as per Satellite Imagery) was 502.21 sq km
in the year 2004. Since the year 2004, with regular implementation of
ant-erosion / bank protection measures by Brahmaputra Board, the
total area of Majuli Island has increased to 520.26 sq km (based on
the Satellite Imagery of February 2011). Thus, not only overall erosion
has arrested, but in fact the trend has reversed favourably. Map of
Majuli Island showing Satellite Imagery of the year 2011 superimposed
on Satellite Imagery of the year 2004 is appended at Plate-6. This map
indicates locations of erosion and locations of reclamation of land
mass in Majuli Island during the years from 2004 to 2011.
Year
Area of Majuli
Island
(in sq km)
Net Area
reclaimed
(in sq km)
2004
502.21
2008
506.37 4.16
2011
520.26 13.89
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5. Future Plan
Remaining protection works, such as completion of five spurs, river
bank revetment, laying porcupines at vulnerable locations,
contemplated under Phase-II and Phase-III are under execution and
targeted to be completed by March 2014.
The ‘Standing Committee of Experts on Majuli’ on its 6th visit of Majuli
Island during the period from 6th to 8th November 2010,
recommended for construction of guide bunds to channelize river
flow with the view to protect Majuli Island from recurring floods and
bank erosion.
6th visit of the standing committee of experts on Majuli under the
Chairmanship of Sri R.C. Jha, Member(RM), CWC
Various alternatives for alignment of guide bunds are to be examined
/ studied through ‘Physical Model Study’ of Majuli Island set up at
North Eastern Hydraulic & Allied Research Institute (NEHARI), North
Guwahati. Final selection is to be made on confirmation through
‘Mathematical Model Study’ assigned to Central Water and Power
Research Station (CWPRS), Pune.
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Physical model of Majuli Island set up at NEHARI
Based upon the ‘Physical Model study’ carried out at NEHARI,
Brahmaputra Board has come out with three alternatives. Preliminary
design, assessment of quantum of work involved and estimation of
financial implication are in advanced stage of finalization. Three
proposed alternatives / options for alignment of guide bunds are
shown in the Plates-7(a) to 7(c). The above proposal will be placed
before the ‘Standing Committee of Experts on Majuli’ for final decision
on alignment of guide bund in its next meeting.
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Siltation at Bengenati due to screen laid during 2008& 2009
and re-strengthened in 2010
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updated Majuli report June'21.pdfPlate 1.pdfPlate 2.pdfPlate 3.pdfPlate 4.pdfPlate 5.pdfPlate 6.pdfPlate 7a.pdfPlate 7b.pdfPlate 7c.pdf