New Delhi, 14 March 2022: There are two types of rivers in the country; i.e perennial rivers and non-perennial rivers. In perennial rivers, water remains available throughout the year, while non-perennial rivers are rain fed rivers in which water flows only during the rainfall period. Flow in the rivers is a dynamic parameter and depends on many sub-parameters such as rainfall, its distribution pattern, duration and intensity in the catchment, health of catchment area, vegetation and withdrawals/utilization of water. The annual average flow data maintained by Central Water Commission (CWC) for last 20 years for major/important rivers in the country does not indicate any significant decline in water availability. However, as per CWC, the per capita annual water availability in the country has progressively reduced due to increase in population, urbanization, improved lifestyle of people, etc.
Government of India, vide Notification dated 9th October, 2018 has notified minimum environmental flows to be maintained in river Ganga from its origin to Unnao in Uttar Pradesh. The notified environmental flow regime is monitored and supervised by Central Water Commission.
Ministry of Environment, Forest & Climate Change (MoEF&CC) in the Standard Terms of Reference (ToR) for conducting the Environmental Impact Assessment (EIA) studies for any proposed River Valley and Hydroelectric Project have mentioned the norms for release of environmental flows, which is 30% in monsoon, 20% in lean season and 25% in non-monsoon & non-lean season to be followed corresponding to flow of 90% dependable year. These norms along with the site specific requirements for environment flow releases as per the studies are then stipulated in the Environment Clearance (EC) letter for compliance.
With regards to the monitoring of the environmental flow releases, the Regional offices of MoEF&CC and Central Pollution Control Board (CPCB) along with the State Pollution Control Boards (SPCBs)/ Pollution Control Committees (PCCs) concerned have been mandated for monitoring of all the environmental aspects of the Hydro Power Projects.
This Information was given by the Minister of State for Jal Shakti, Bishweswar Tudu in a written reply in Rajya Sabha today.