Lok Sabha Question No. 229 (UNSTARRED), answered on 2026-01-29
Subject: Severe Siltation in Dams
Ministry: JAL SHAKTI
Asked by: Shri  Selvaganapathi T.M.

## GOVERNMENT OF INDIA

## MINISTRY OF JAL SHAKTI

## DEPARTMENT OF WATER RESOURCES, RIVER DEVELOPMENT & GANGA REJUVENATION

## LOK SABHA UNSTARRED QUESTION NO. 229

ANSWERED ON 29.01.2026

## SEVERE SILTATION IN DAMS

## 229.   SHRI SELVAGANAPATHI T.M.:

Will the Minister of JAL SHAKTI be pleased to state:

(a) whether it is a fact that most of the dams in the country are facing severe siltation which reduces their effectiveness in flood control and water storage according to a study conducted by the Indian Institute of Science Education and Research and if so, the details thereof;

(b)  whether  it  is  also  a  fact  that  a  majority  of  the  dams  have  lost  more  than  fifty  per  cent  of  their  total reservoir  storage  capacity  and  ten  reservoirs  on  east-flowing  rivers  and  seven  reservoirs  on  west-flowing rivers are projected to exceed fifty per cent loss of storage capacity by 2050 posing a serious threat to water security in the country and if so, the details thereof;

(c)  whether  the  said  study  has  recommended  the  need  for  immediate  attention  and  management interventions in this regard; and

(d) if so, the details thereof along with the steps taken/proposed to be taken by the Government in response to the above findings which are serious in its totality?

## ANSWER

## THE MINISTER OF STATE FOR JAL SHAKTI

## ( SHRI RAJ BHUSHAN CHOUDHARY )

(a)  to  (d) In  September  2025,  Indian  Institute  of  Science  Education  and  Research  (IISER)  Bhopal,  an autonomous  institute  under  the  Ministry  of  Education,  Government  of  India  published  a  study  report highlighting the severe extent of siltation in India's large dams. The study noted significant storage losses in several  reservoirs,  affecting  water  supply,  hydropower,  and  flood  moderation,  with  further  reductions expected  in  east-  and  west-flowing  basins.  It  emphasized  the  need  for  more  detailed,  site-specific investigations to better quantify sedimentation processes and support informed reservoir management.

The study draws upon the Compendium on Sedimentation of Reservoirs in India published by the Central  Water  Commission  in  2020,  which  was  subsequently  updated  in  August  2024.  This  publication analysed capacity surveys of over 548 reservoirs, including detailed gross storage data for 439 reservoirs, which  together  account  for  nearly  80%  of  the  India's  total  dam  gross  storage.  The  analysis  revealed  an overall  storage  loss  of  15.46%,  with  the  Deccan  Peninsular  region  (17.48%)  and  the  Himalayan  region (17.19%) identified as the most severely affected.

Siltation  in  reservoirs  is  an  inevitable  natural  phenomenon,  which  cannot  be  avoided  altogether. While designing the dam reservoirs projects, considering the likely deposition of silt in reservoirs, provision of dead storage is kept. This dead storage which is also part of gross storage does not contribute in flood control and conservation storage. However, in case the dead storage is lost at a rate substantially higher than the  designed  rate  or  significant  loss  of  live  storage  capacity  is  there,  action  for  sediment  management  is required  to  be  taken  by  the  dam  owners.  In  case  of  India,  majority  of  the  dams  are  owned  by  State Government, the action for sediment management is required to be taken by the States/other dam owners.

However,  considering  the  importance  of  sediment  management,  various  guiding  documents  have been published by the Central Government to guide the dam owners on these matters. In order to assist State Government  in  the  matters  related  to  sediment  management,  guidelines  on  'Assessing  and  Managing Reservoir Sedimentation' and 'Operational Procedures for Assessing and Managing Environmental Impacts in Existing Dam Projects' was published in 2019 and 2020 respectively.  In addition to above, Government of  India  published  a  National  Framework  on  Sediment  Management  in  October,  2022  to  assist  the  State WRDs/dam owners to deal with the matter of sediment management.

Furthermore, in order to sensitize the states and dam owners for undertaking sediment management activities  with  focus  on  desilting  of  reservoirs,  workshop  was  organized  on  09.01.2026  wherein  the experience related to activities pertaining to desilting being carried out by some of the states viz. Rajasthan, Kerala, Punjab & Gujarat were shared with the participants.

Under the  externally  funded  Dam  Rehabilitation  and  Improvement  Project  (DRIP)  Phase  II  &  III, provisions  have  been  made  for  need-based  de-siltation  and  sediment  management  works  in  select  pilot reservoirs, aimed at restoring lost capacity to the maximum feasible extent.

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