In News:

• In a first, the Union government has mandated the minimum quantity of water or ecological flow as it’s called in scientific circles that various stretches of the Ganga must necessarily have all through the year.

About:

• The River Ganga is the most sacred and deeply revered by the people of this country and the Ganga river basin is the largest river basin in India in terms of catchment area,constituting twenty-six per cent of the country’s land mass and supporting about half a billion
• In India alone, approximately 5,100 large dams dot the rivers, making India rank third in the world with regards to the number of large dams. These structures have irretrievably changed the downstream flow patterns, consequently affecting water quality, temperature, sediment movement and deposition.
• The new norms would require hydropower projects located along the river to modify their operations so as to ensure they are in compliance with new environment flow norms. E-flow (ecological flow) is the quantum of water that must uninterruptedly flow in the river in all the seasons, required for the river to perform all its ecological functions including sustenance of fauna and its human dependents
• Indiscriminate human intervention, in the form of river course diversion, river-bed mining, and damming, has altered the environmental flow of rivers.

Benefits of Ecological Flow:

• Ecological flows help in numerous ways like groundwater recharge, nutrient balancing, fish spawning and sediment flushing. At the same time, free-flowing rivers and stretches also provide innumerable community services like fisheries, tourism and water supply.
• It keeps the biodiversity in that area in fine balance

Water flow Requirements:

• Upper Ganga River Basin Stretch starting from originating glaciers and through respective confluences finally meeting at Devaprayag up to Haridwar
• Stretch of main stem of River Ganga from Haridwar, Uttrakhand to Unnao, Uttar Pradesh

River flow picture:

World experiences:

• These legislations attempt to ensure required minimum flow in the river system to sustain ecosystem services.
• The Mekong River Agreement, 1995
• South Africa’s National Water Act, 1998 and the
• Swiss Water Protection Act, 108