Lok Sabha Question No. 2132 (UNSTARRED), answered on 2016-03-10
Subject: Study on Brahmaputra
Ministry: WATER RESOURCES, RIVER DEVELOPMENT AND GANAGA REJUVENATION
Asked by: MAULANA BADRUDDIN AJMAL

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

## LOK SABHA

## UNSTARRED QUESTION NO. 2132 ANSWERED ON 10.03.2016

## STUDY ON BRAHMAPUTRA

## 2132. SHRI BADRUDDIN AJMAL

Will  the  Minister  of  WATER  RESOURCES,  RIVER  DEVELOPMENT  AND  GANGA REJUVENATION be pleased to state:

(a)  whether  any  study  on  Brahamaputra  River  erosion  and  its  control  has  been  conducted  by Indian Institute of Technology, Roorkee;

(b) if so, the details thereof along with recommendations made therein including follow up action taken by the Government thereon; and

(c) the funds allocated/released for erosion control in Assam during the last five years?

## ANSWER

## THE  MINISTER  OF  STATE  FOR  WATER  RESOURCES,  RIVER  DEVELOMPMENT  & GANGA REJUVENATION

( Prof. SANWAR LAL JAT )

(a) Yes,  Madam.  National  Disaster  Management  Authority  (NDMA),  Government  of  India requested the IIT Roorkee in April, 2008 to conduct a Study of Brahmaputra River Erosion and its Control .

After incorporating the comments on the draft report given by CWC, Brahmaputra Board and Water Resources Department of Government of Assam, the Final Report on the above study was submitted by IIT Roorkee to NDMA in May, 2012.

- (b) The recommendations made in the Study carried out by IIT Roorkee include;
-  Sediment ingress in Brahmaputra River has to be controlled vigorously in addition to developing cost-effective erosion control measures such as multiple tier RCC Jack Jetty Field system,
-  Closures of subsidiary channels has to be undertaken,
-  The  mathematical  models  developed  for  the  river  system  need  to  be  improved periodically  in  addition  to  developing  new  flood  forecasting  &  channel  improvement models,
-  Undertaking field pilot studies,

-  Strengthening and upgrading of existing data acquisition and processing infrastructure by procuring new equipment/ data,
-  Creation of comprehensive data base, and
-  The need for establishment of an autonomous well-equipped R&D Centre.

The detailed recommendations of the study are given at Annexure-I .

Flood  Management  is  the  prime  responsibility  of  State  Government,  Water  being  a  State subject. Government of India provides promotional support to the State Governments in this regard.  Accordingly, the Government of  India had launched Flood Management Programme (FMP) in XI Plan for providing promotional support to the State Governments for undertaking works related to flood control, river management, anti-erosion, restoration of damaged flood management  works  and  anti-erosion.  The  continuation  of  FMP  during  XII  Plan  had  been approved by Cabinet in October, 2013 with an outlay of Rs. 10,000 crore and scope of FMP was extended to cover catchment area treatment works.

- (c)    During last five years (2010-11 to 2015-16) till date the central assistance of Rs. 461.84 crore has been released to Government of Assam under Flood Management Programme (FMP) for flood management and anti-erosion works.

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## Annexure-I

Annexure referred to in reply to part (b) of Unstarred Question No. 2132 due for reply in Lok Sabha on 10.03.2016 regarding Study on Brahmaputra

## Detailed recommendations of the study carried out by IIT, Roorkee:-

1. Data analysis and computer simulation studies conducted in the present study have succinctly brought  out  that  the  prime  causative  factor  of  stream  bank  erosion  vis-a-vis  channel instability processes of the Brahmaputra can be attributed to inherent "sediment overloading" of the river fluvial system accompanied by intensification of channel braiding configuration. In  the  light  of  aforesaid  observation,  it  is  recommended  to  rigorously  control  sediment ingress into the Brahmaputra river system through comprehensive watershed management as well as development programme; and also undertake sustainable channelization measures by effecting  closure  of  subsidiary  channels  through  adoption  of  appropriate  river  training techniques.
2. In view of the fact that extensive extent of stream bank-line is under grip of unabated erosion process,  it  is  recommended  to  deploy  cost-effective  erosion  control  measures,  namely multiple tier RCC Jack Jetty Field system along with submerged vanes as per site condition feasibility. The required layout of Jack Jetty field may be appropriately devised by carefully considering the suitable Jack Jetty Density Index (JJDI) and Jack Jetty Submergence Index (JJSI)  at  the  time  of  implementation  of  field  pilot  schemes  after  duly  accounting  for  the prevailing  river  configuration.  The  Jack  Jetty  Field  can  be  desirably  designed  to  reclaim eroded land from the river.
3. The braiding phenomenon of the Brahmaputra has displayed a sharply increasing trend in the recent decades giving rise to highly disturbing incidence of channel instability in the wake of stream  bank  erosion  process.  As  stated  earlier,  it  is  recommended  to  urgently  undertake measures  to  control  the  rise  of  braiding  intensity  through  effective  closure  of  subsidiary channels  with  the  help  of  Jack  Jetty  Screen  and  submerged  vanes  protected  by  Reno Mattress.
4. To  start  with,  field  pilot  studies  may  be  undertaken  at  two  sites  -  one  near  SoalkuchiGauwahati and other near Morigaon(Bhuragaon) for which preliminary  designs have been evolved. The preliminary design- may be desirably fine-tuned at the time of implementation as mentioned at para 2 above, as well as after critically reviewing their performance in the post flood season.
5. The R&D endeavour of the present study to evolve ANN models for simulating hydrologic response  for  runoff  and  sediment  of  Subansiri  tributary  watershed  which  is  the  largest tributary of the Brahmaputra system is found to be quite encouraging. It is recommended to use and periodically improve these models with availability of more field data in future and also replicate similar modeling for other major tributaries.
6. The mathematical model developed herein as a preliminary work with the help of HEC-RAS 4.1  may  be  used  on  trial  basis  to  start  with  for  flood  forecasting  and  preliminary  channel improvement purposes. However, a fully dedicated comprehensive study is recommended to develop  a  fully  mobile  river-bed  and  stream-bank  erosion  model  which  is  capable  of simulating  complex  fluvial  phenomena  of  the  Brahmaputra  such  as  secondary  flow  /  flow vortices, turbulence & mass dispersion of sediment-laden flow using concept of Reynolds's stresses, hydraulic transients of water and sediment, and morphodynamic fluxes as per stateof-the-art.
7. On account  of  the  prevalent  inadequacy  of  reliable  and  consistent  field  data,  modeling  in relation  to  erosion,  sediment  inflow  and  flood  forecasting  may  have  certain  elements  of inconsistencies  and  discrepancies,  resulting  in  fallacious  prediction  of  future  scenario.  It urgently  warrants  strengthening  and  upgrading  of  existing  data  acquisition  and  processing infrastructure  at  the  ground  level  of  the  concerned  agencies.  Following  equipment/data should urgently be procured for the existing or proposed data acquisition establishments of the field agencies / organizations.
8. (i) Data acquisition instruments -
- a. Acoustic Doppler current profilers (ADCPs)
- b. Ultrasonic Flow Meter / Fluorometer
- c. Latest Sediment Sampler
- d. Portable Suspended Sediment Analyzer
- e. Laser Particle Size Analyzer
- f. Total Station and GPS
- g. Automatic Gauge Level Recorder
- h. Laser Doppler Velocimeter (LDV) with phase Doppler particle Analyzer (PDPA) for R&D purposes
17. (ii) Upgrading of Surveyed Hydrographic Data
- a.  survey  of  cross  sectional  data  interval  should  be  of  the  order  of  500m  at  least between two given sections for good quality mathematical model development and analysis.
- b.  The  cross-sections  survey  should  be  updated  regularly  (at  say  every  five  years interval) depending on observed hydrological events.
- c. Flow measurements for high flood events using automated system.
21. (iii) Optical and Microwave Satellite Data Procurement
- a. For monitoring and change detection of spatial and temporal features in the river and in the basin including flood plain.
23. (iv) Improving the spatial density of hydro-meteorological data acquisition network
- a.  Hydrological  data  (stage,  Discharge  &  Sediment)  observation  stations  may  be increased  by  including  /  restoring  sites  near  Tezpur  (Koliabhomora  Bridge), Bessamara  (Majuli),  Bogibeel  (New  Bridge  near  Dibrugarh),  in  addition  to  the existing sites at Pandu & Jogighopa.
- b. The spatial density of Meteorological stations requires to be significantly upgraded along with installation of the latest data acquisition and data logging systems.
26. (v)  Development  of  Management  Information  System  (MlS)  for  main  stem  Brahmaputra along with the flood plain / catchments, tributaries.
8.   Capacity building of the technical manpower  associated at various levels of river management is recommended through periodic professional training on latest advances in the technology
9.    Creation  of  a  comprehensive  data  base  comprising  all  pertinent  data  &  information  using latest data management system.
10. Establishment  of  an  autonomous  well-equipped  R&D  centre  to  be  manned  by  highly competent manpower for conducting applied research at state-of-the-art level.