NEW DELHI: Rejuvenating the Ganga's waters and maintaining the river's purity can be one of the best ways to keep the Sundarbans alive and protect it from effects of climate change, NMCG Director General Rajiv Ranjan Mishra said.
According to Mishra, it is crucial to have a minimum environmental flow in the river at all times to prevent the sea from degrading the soil, and making the groundwater unfit for drinking and irrigation.
Climate change could accelerate salt water intrusion into fertile soils due to rise in sea levels.
Excess groundwater extraction in dry regions of the world could also increase soil and groundwater salinity, he said.
Due to climate change, the Sundarbans, one of the world's largest mangrove forest, faces several challenges.
With rising sea levels, islands are disappearing and the increasing salinity in the water and soil has severely threatened the health of mangrove forests and the quality of soil and crops.
"In the monsoons, when the rivers are in full spate, they keep the saline waters of the Bay of Bengal at an arm's length by pushing them deeper into the sea. This prevents the saline water from entering the mangrove forests," Mishra told PTI.
However, when the water level recedes during the lean season, the saltwater pushes into the mangrove forest and even further into the farmlands, thereby destroying not just the crops but the soil for future cultivation.
"Hence, it is extremely important to have a minimum environmental flow in the river at all times to prevent the sea from degrading the soil, making the groundwater unfit for drinking and irrigation," he said.
The government has mandated the minimum quantity of water that various stretches of river Ganga must necessarily have all through the year.
Mishra, who superannuates on Friday, further elaborated on his journey as the chief of National Mission for Clean Ganga (NMCG) and also how the project to rejuvenate the river progressed, in his new book 'Ganga: Reimagining Rejuvenating Reconnecting'.
He has co-authored the book with Puskal Upadhyay, an IDAS official who has been a part of the mission.
Mishra, an alumnus of IIT Kanpur and a 1987 batch IAS officer, said the book is an attempt to put in perspective the challenges, the new approach and thinking which developed the Namami Gange Programme into the most comprehensive river rejuvenation exercise.
Noting that the 'sacred' river is now crying out for rejuvenation, Mishra said returning the Ganges to its virgin state, as officials of the NMCG realised soon enough, was an extraordinarily difficult and a complex task that called for cooperation and activism from all stakeholders on a mission mode, a perfect example of tackling the so-called 'wicked problem'.
"What makes Namami Gange truly stand out from previous efforts for the Ganga rejuvenation is its adoption of a holistic and multi-sectoral approach which does not limit itself to cleaning of the river but extends to rejuvenation and restoration of the entire riverine ecosystem. And I think this has been its biggest strength, as well as challenge for the future," he said.
According to Mishra, the Dissolved Oxygen (DO) level has improved in 27 locations, the Biological Oxygen Demand (BOD) levels has improved in 42 areas and the quantity of Faecal Coliform (FC) in the water has been reduced in 21 places.
The important parameter to be met, keeping DO more than 5 mg/l, has now been successfully achieved and attained throughout the 2,525-km-long river, which is a proof of the improved river water quality, he said.
"The BOD level is also under the set standards, i.e.3 mg/l, except at two stretches of the river, where it is just exceeding the limit ranging 3 mg/l - 5mg/l. Moreover, the water quality has reached Class A, the highest standard for water quality, up till Haridwar in Uttarakhand. This has been a big achievement for the mission," Mishra said.
He said the work is now being extended to include River Ganga's tributaries such as River Yamuna, River Hindon, River Gomti, River Ramganga, amongst others.
"In the future, deliberate action plans must be rolled out to take this work further and rejuvenate the riverine ecosystems of these smaller rivers as well. In the same line, as you may be aware, we have released the ecological flow notification for River Ganga, which recognizes the right of the river over its own water. We are also in the process of releasing the notification for River Yamuna," he said.
Rhe biggest challenge ahead of the mission is to sustain the various measures undertaken so far, Mishra said.