For Delhi’s survival, let Yamuna be a river again
ralta (uninterrupted flow) in the river will follow Nirmalta (purity). But the two go together,” explains Manoj Misra, a river activist who petitioned the NGT in the ongoing case on the cleaning of the Yamuna.
A flowing river not only cleanses itself naturally, it also carries along sediments, life forms and energy that conserve local biodiversity. A study by environmentalists Vikram Soni, Shashank Shekhar and Diwan Singh in 2014 found that to perform these functions and recharge the aquifers, the Yamuna in Delhi needed at least 50–60% of its natural flow throughout the year. However, only 32% of the natural annual flow was allowed in the river at the time of the study. During the nonmonsoon months, it dropped to a meagre 16%.
While experts insist on a minimum perennial flow during all seasons, the government has proposed to build a dam upstream to store water during monsoon and release it during the lean months. While the court is examining the proposal, Misra points out that the monsoon is the only time when a river recharges the aquifers, which in turn feed the river for the rest of the year.
The Yamuna with its sand aquifer that runs two km wide and nearly 40 metres deep along the 48-km stretch in Delhi is the city’s best non-invasive storage of fresh water. “As much as 100 MGD can be extracted from it sustainably if the floodplains are maintained well. So why would you need a dam?” asks Diwan Singh.
Today, Delhi draws from the Yamuna to support over 40% of its 913 MGD water supply. No river can survive such extraction for too long. To channel more freshwater into the river, both Delhi and Haryana need to be on the same page, which will require a great deal of political will. Haryana itself can save water by encouraging farmers to give up water-intensive crops and engage in efficient irrigation techniques. To save its lifeline, Delhi must fix the basics:
Delhi’s water policy estimates that the city can capture 140 MGD from rainwater runoffs alone. Right now, it just flows down the drain. Delhi needs to revive its natural water bodies, which met much of the local water requirement across the city till not so long ago.
Delhi must cut down on leakages and pilferage. As much as 30% of Delhi’s treated water is wasted in distribution, while the National Water Policy says only 15% is acceptable.
To beat the waste-and-want dynamics, Delhi has to reduce consumption and invest in recycling. Under the water policy, the capital must increase its recycled wastewater use to 70% by 2023 and at least 80% by 2026 to meet its non-drinking requirements. Even today, the city’s affluent rather criminally use drinking water to flush toilets, wash cars and water lawns.
Delhi’s future hinges on the survival of the river that has nourished it for centuries. The Yamuna is still the city’s best bet for long-term water security.
Only if we stop sucking it dry.