The status of the river Yamuna in the Delhi stretch is a reflection of our activities in the city. Delhi receives 90% of its fresh water supply from river Yamuna, river Ganga and the Bhakra storage (via western Yamuna canal). Delhi is endowed due to its proximity to the Ganga and Sutlej basins, which have helped the city address its rising water demand (currently at approximately 5,000 million litres per day).
Over the years, the contribution from these two river basins has increased significantly, yet most of the wastewater (treated or otherwise) drains into the Yamuna through 17 primary drains. Delhi has 18 Sewage Treatment Plants (STP) to treat the sewage generated in different parts of the city.
The treated wastewater eventually flows to the Yamuna through the 17 drains, the largest being the Najafgarh drain. In addition, Najafgarh drain carries wastewater from Gurugram which drains into the Najafgarh jheel through the Badshahpur drain in Gurugram, Haryana. The direction of flow of all the 17 drains (erstwhile storm water drains) is towards the river Yamuna as it is located naturally at the lowest elevation in the city. Most of the water logging that the city faces during the monsoon season usually is also at these lowest elevations.
Over the years our lifestyle has changed and so has the quality of wastewater. This is reflected in the frothing in the Yamuna (caused by phosphate-based detergents) and the recent detection of microplastics in the river water, groundwater and river sands. The presence of persistent organic pollutants (POP) in the water is another cause of concern. All these pollutants are resistant to biodegradation, have a long life and therefore have a long residence time in the water.
The contamination in the river water has led to the groundwater being contaminated in the unconfined aquifers along the Yamuna flood plains. In addition, the two major landfills near the Yamuna (Bhalswa and Ghazipur) contribute to the contamination of groundwater and river water. There exists a very delicate interlinkage between surface water and groundwater, which is not often evident and therefore poorly understood. The progressive loss of wetlands and biodiversity on the floodplains has robbed the river of its capacity for resilience.
The urban water system of Delhi is challenged by a variety of problems, which includes a persistent inability to sustainably meet its water demand. Delhi cannot be perpetually importing river water from outside its catchment. The failure to collect and dispose of wastewater (typically access to safe drinking water is a commitment we have met, while treatment of wastewater lags behind in city planning) and sharp deterioration in the quality and quantity of surface and ground water sources is a consequence of that crumbling ageing water infrastructure, leading to a significant loss of freshwater through leakages besides poor finances for managing municipal agencies.
While providing water to Delhi’s citizens is important, it ought to be predicated on plentiful freshwater sources, unlimited sinks for wastewater (the status of river Yamuna is a consequence of that) and cheap energy for operating water infrastructure. The governance that emerges is extremely linear in water use, centralised in resource management, and blind to hydrogeomorphology. Delhi has a dynamic fluvial activity in and around the river and is losing vital natural resources through pollution.
It is important that Delhi’s citizens consider the river Yamuna as its own, identify hot spots on sources of pollution and practice decentralised governance for water use so that wastewater does not reach the Yamuna. Reimagining the Najafgarh drain as a clean waterway encircling the western and northern parts of the city and building back the biodiversity and wetlands in the floodplains will go a long way in restoring the Yamuna to its pristine glory.
Effective river water resource management will need the Central and state governments to work closely to devise an action plan, especially taking different climate change scenarios into consideration.
Ranjana Ray Chaudhuri, PhD
Associate Professor, Head Department of Regional Water Studies & Department of Natural and Applied Sciences, TERI School of Advanced Studies, New Delhi.
