Lok Sabha Question No. 5481 (UNSTARRED), answered on 2017-04-06
Subject: National Silt Policy
Ministry: WATER RESOURCES, RIVER DEVELOPMENT AND GANAGA REJUVENATION
Asked by: VINAYAK BHAURAO RAUT, DHARMENDRA YADAV, KUNWAR HARIBANSH SINGH, GAJANAN CHANDRAKANT KIRTIKAR, SHIVAJI ADHALRAO PATIL, PARVESH SAHIB SINGH, SUDHEER GUPTA, SUNIL BALIRAM GAIKWAD, Shrirang Appa Barne, ASHOK SHANKARRAO CHAVAN, ANANDRAO  ADSUL, T. RADHAKRISHNAN, VINOD KUMAR BOIANAPALLI, VIJAY KUMAR S.R., SHRIKANT EKNATH SHINDE, PRITAM GOPINATH MUNDE

## GOVERNMENT OF INDIA MINISTRY OF WATER RESOURCES, RIVER DEVELOPMENT & GANGA REJUVENATION

## LOK SABHA

## UNSTARRED QUESTION NO. 5481

ANSWERED ON 06.04.2017

## NATIONAL SILT POLICY

| 5481. SHRI VINAYAK BHAURAO RAUT KUNWAR HARIBANSH SINGH SHRIADHALRAO PATIL SHIVAJIRAO SHRI SUDHEER GUPTA SHRI SHRIRANG APPA BARNE SHRI T. RADHAKRISHNAN   | SHRIDHARMENDRA YADAV SHRI GAJANAN KIRTIKAR SHRI PARVESH SAHIB SINGH DR. SUNIL BALIRAM GAIKWAD SHRIANANDRAO ADSUL SHRI B. VINOD KUMAR   |
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Will the Minister of WATER RESOURCES, RIVER DEVELOPMENT AND GANGA REJUVENATION be pleased to state:

- (a)  whether  it  is  a  fact  that  many  rivers  have  over  the  years  lost  their  capacity  to  hold  water  due  to deposition of excessive silt and if so, the details thereof;
- (b)  whether  the  Government is planning to come out with a National Silt Policy to handle threat of floods  in  many  parts  of  the  country  during  Monsoon  and  to  address  the  issue  of  sedimentation  and dredging and if so, the details thereof;
- (c) whether many committees have been constituted in the past to look into the said problems in rivers in the country and if so, the details of the recommendations made by these committees;
- (d) the action taken by the Government on the suggestions made by these committees and the extent to which the action taken so far thereon has been able to tackle the silt problem; and
- (e) the time by which the said policy is to be implemented including the other steps taken/being taken by the Government in this direction?

## ANSWER

THE MINISTER OF STATE IN MINISTRY OF WATER RESOURCES, RIVER DEVELOPMENT AND GANGA REJUVENATION (DR. SANJEEV KUMAR BALYAN)

(a) (b) & (e)  Erosion and deposition of silt is a natural process in alluvial rivers. The rivers pick up and drop their silt load as per their regime condition. The decrease in water depth of river is caused  due  to  siltation  of  river  bed  in  specific  reaches,  which  depends  on  various  factors  viz. discharge in the river, river slope, morphology, nature of silt etc.

Regarding formulation of a comprehensive policy on sediment management in rivers in the country, a National Conference on Sediment Management in Indian rivers was organised by this Ministry on 17.03.2017which was attended by many experts and senior officials from Central/ State  Governments.  The  Conference  made  number  of  recommendations  regarding the policy

framework  on  Sediment  Management  in  Indian  rivers.  The  time  required  for  formulation  of policy depends upon consultations with stakeholders.

(c) & (d) The Ministry had constituted the following Committees to study the problem of silting of rivers.

(i)    A  Committee headed by Dr. B.K. Mittal, former Chairman, Central Water Commission in 2001 to study the problem of silting in the rivers.

- (ii)    A  Committee  headed  by  Shri  Madhav  Chitale,  Expert  Member,  NGRBA  in  2016  for preparation  of  guidelines  for  works  on  de-siltation  from  Bhimgauda  (Uttarakhand)  to  Farakka (West Bengal).

(iii)    An  Expert  Committee  on  Erosion  and  Siltation  in  Rivers  (ECESR)  headed  by  Director, CWPRS,  Pune  in  2016  to  study  the  problem  of  erosion,  siltation  and  requirement  of  desiltation/dredging of rivers particularly in Brahmaputra and Ganga.

The details of these Committees are at Annex-I

The measures of flood management including desilting of rivers are formulated by the State Governments  as  per  their  priority.  The  Government  of  India  supplements  the  efforts  of  State Governments by providing technical guidance and promotional financial assistance for critical areas. The suggestions have been forwarded to the State Governments. The Government of India had launched Flood Management Programme (FMP) for providing central assistance to States for works  relating  to  river  management,  flood  control,  anti-erosion,  drainage  development,  flood proofing,  restoration  of  damage  flood  management  works,  anti  sea  erosion,  catchment  area treatment works etc.

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## ANNEXURE  REFERRED  TO  IN  REPLY  TO  PART  (c)  to  (d)  OF  LOK  SABHA UNSTARRED QUESTION NO. 5481 FOR ANSWER ON 06.04.2017 REGARDING 'NATIONAL SILT POLICY'

## 1. Committee headed by Dr. B.K.Mittal, former Chairman, Central Water Commission(2001).

Ministry of Water Resources set up a Multi-Disciplinary Committee  in  year 2001 under the Chairmanship of Dr. B.K. Mittal, Former Chairman, Central Water Commission, to identify  cause  and  extent  of  siltation  in  rivers,  suggest  measures  to  minimize  siltation, examine as  to  whether  desilting  is  a  technically  feasible  means  to  minimize  magnitude  of floods  in  rivers,  suggest  appropriate  technology/  methods  of  desilting  of  rivers  if  found technically  feasible,  find  economic  viability  of  desilting  of  rivers,  propose  a  realistic operational programme in a time-bound manner.

The main recommendations and suggestions of the Committee are as under:

- (i) The desilting in general is not feasible technically, due to several reasons like nonsustainability, non-availability of vast land required for disposal of dredged material etc. the desilting by dredging in general should not be resorted to particularly in major rivers.  Some  locations  such  as  tidal  rivers,  confluence  points  and  the  likes  can  be tackled  by  desilting  after  thorough  examination.  Desilting  of  rivers  can  marginally minimise the magnitude of floods and be effective only for a short period. Desilting is not  recommended  on  a  large  scale.  However,  desilting  can  be  done  in  vulnerable reaches for some specific purpose like for improving the hydraulic characteristics of the river. For navigation purpose, the river waterways need to be dredged every year to have minimum depth of water.
- (ii) Desilting of rivers for flood control is not an economically viable solution.
- (iii) Aggradation,  contrary  to  the  general  impression  is  not  pronounced  and  alarming. Though there is heavy sediment load in rivers, the natural process of 'self scouring' ensures that there is no substantial aggradation, in totality.
- (iv) The method of minimising siltation may be of two fold; one that is required in the catchment and other in the river self.The method to be adopted in the former viz. the catchment  may  include  afforestation,  right  practice  of  land  use,  catchment  area treatment. The  method  in  respect  of  later viz 'the river itself'  may  include construction of suitable hydraulic structures that may trap silt.
- (v) The Committee is of the opinion that where siltation has taken place on one bank and erosion on the other bank of river, silt can be removed from deposit area and dumped in suitable area with proper investigation.
- (vi) The  carrying  capacity  of  a  river  should  be  monitored  on  regular  basis  to  obtain  a correct knowledge regarding aggradation/degradation.

## 2. Committee headed by Shri Madhav Chitale, Expert Member(NGRBA)(2016)

The  National  Mission  for  Clean  Ganga  (NMCG),  Ministry  of  Water  Resources,  River Development  and  Ganga  Rejuvenation  (MoWR,  RD  &  GR)  constituted  a  Committee  for preparation of guidelines for works on de-siltation from Bhimgauda (Uttarakhand) to Farakka (West Bengal) under the Chairmanship of Shri Madhav Chitale, Expert Member, NGRBA in July, 2016. The main recommendations of the committee are as under:

- (i) Erosion,  sediment  transport  and  siltation  in  large  rivers  like  Ganga  are  very  complex phenomena and their estimation has inherent limitations and uncertainties. A reconnaissance  of  main  River  Ganga  reveals  that  different  reaches  are  in  a  dynamic equilibrium phase. Sedimentation is mainly seen downstream of Bhimgauda barrage and near the confluences of tributary rivers with Ganga.
- (ii) Though de-siltation works can improve hydraulic performance of the river and this itself can justify undertaking de-siltation, these have no direct role in improving environment flow  in  the  river.  On  the  other  hand,  indiscriminate  de-silting  or  sand  mining  would cause adverse impacts on river e-flow.
- (iii) River Ganga tends to achieve equilibrium on its own given the hydrology, sediment and natural bed and bank disposition. It is necessary to provide the river sufficient areas of flood plain and lakes along the river to moderate the flood level. Any encroachment of flood plain, reclamation of lakes or disconnection of lakes from river should be avoided; rather adjoining lakes/depressions may be de-silted to increase their storage capacities.
- (iv) Comprehensive Catchment Area Treatment and Watershed Development works, along with  good  agricultural practices and  river  bank  protection/anti-erosion  works  are necessary to reduce silt inflow into the river system.
- (v) Upstream reaches of natural constriction works,  like barrages/bridges, etc., tend to get silted  leading  to  wandering  of  river.  Possibly  river  training,  cut-off  developments  and provision of extra water way near the constrictions could be tried after proper assessment without impacting the morphology of river elsewhere. Efforts should be made to provide silt continuity along the weirs and barrages.
- (vi) The proposed desilting  of any river reach need  to be justified bringing  out clearly the flooding caused due to siltation along with technical comparison of the alternative flood mitigation  measures  with  'do  nothing'  or  'proposed  desilting/  dredging'  being  other options. It should invariably be associated with sediment flux studies and morphological studies to confirm no significant adverse effect on downstream or upstream reach of the river  including  the  safety  and  effectiveness  of  river  crossings,  water  intakes,  existing river bank / flood protection measures etc.
- (vii) Reservoirs in main river Ganga and its tributaries, particularly in upper reaches, should be operated in such a manner that first floods, having high silt load, are allowed to pass through without storage and river flows in later phases of the monsoon are only stored for use during non-monsoon season. This would require quantitative long term forecast with decision support system to be established for optimum reservoir operations.
- (viii) The proposal should also contain environmentally acceptable and practically feasible silt disposal plan. River gravels/sands/silts could be used gainfully in construction works, including housing, roads, embankment and reclamation works. Under no circumstances, disposal should create any contamination of the water bodies, harmful to the flora and fauna  existing  adjacent  to  the  disposal  sites.  It  should  also  be  ensured  that  disposed material should not come back into the river again.
- (ix) The dredging/desiltation/mining activities may result into some adverse impacts, i.e. (a) River bed degradation; (b) Bank erosion; (c) Channel widening; (d) lowering of  water surface elevations in the river channel; (e) lowering of water table elevation adjacent to the river; (f) a reduction in the structural integrity of bridges, pipelines, jetties, barrages, weirs,  foundations  supporting  high  tension  lines,  existing  bank  protection  works  and other  manmade  structures;  and  (g)  a  loss  of  environmental  values  resulting  from  (a) through (e). As such, restrictions need to be enforced before planning and executing any dredging/ de-silting / mining activities.

## 3. Expert Committee on Erosion and Siltation in Rivers(ECESR)(2016)

The  Ministry  has  constituted  an  Expert  Committee  on  Erosion  and  Siltation  in  Rivers (ECESR)  in  May,  2016  to  study  the  problems  of  erosion,  siltation  and  requirement  of desiltation  /  dredging  of  rivers,  particularly,  Ganga  and  Brahmaputra  rivers  and  suggest remedial measures. The Committee will study and review the recommendations of various important  Expert  Committees  constituted  in  past  on  siltation  of  rivers  and  recommend suitable measures of erosion control and appropriate combination of raising and strengthening  of  existing  embankments,  measures  to  control  siltation  of  river  beds  and techno-environmentally permissible de-siltation/dredging of river beds for providing adequate waterways to safe passage of flows in floods.

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