NEw Delhi: In what can be construed as an admission that mushrooming dams have destroyed rivers and their environmental flow, or e-flow, the ministry of water resources has directed the Central Water Commission (CWC) to not approve or design any dam until a committee formed to determine the quantum of e-flow submits its report.

The move can have serious repercussions on the National Democratic Alliance (NDA) government’s plans of harnessing hydropower to increase the country’s power generation capacity as a delay in approval of design could result in delays in dam construction.

“Environmental flow of rivers is a necessity for survival of a river and also for it to perform its ecological functions and to ensure that cultural dependence of the community is maintained. Unfortunately, in the past, structures like dams and barrages were designed without factoring in e-flow. In the process, not only have the rivers got fragmented, most of the floral and faunal species have also become extinct," read a letter written by Shashi Shekhar, secretary in the ministry of water resources, river development and Ganga rejuvenation, to CWC chairman A.B. Pandya.

“There are certain stretches where a river has become completely dry," he added.

The letter, dated 25 August, has been reviewed by Mint. It stated that minister Uma Bharati wanted CWC to not approve any dam or barrage without factoring in e-flow.

“The quantum of e-flow is being determined by a committee which is yet to submit its report. Therefore, I have been asked to inform you that till the committee submits its report, CWC may not approve... any dam or barrage or any structure..." the letter stated.

A panel, including professors from several Indian Institutes of Technology, and other experts, has been studying the impact of existing and proposed dams on the e-flow of rivers. It was set up earlier this year and is expected to submit its report in three to six months.

As per the World Bank definition, the e-flow of a river can be described as “the quality, quantity and timing of water flows required to maintain the components, functions, processes and resilience of aquatic ecosystems which provide goods and services to people".

River flows are modified when water is withdrawn for agriculture, urban use and hydropower and not returned to the river through drainage or groundwater flow.