Weakened flow is killing the Yamuna

Ahead of Delhi polls, many articles on Yamuna cleaning emerged, highlighting sewage treatment up to mandatory tertiary discharge standards as key solution

A spate of articles on cleaning the Yamuna appeared around the Delhi assembly elections in February. Among the solutions talked about was the treatment of sewage till it attains the mandatory, tertiary treatment level discharge standards. Capital and technology for this solution are readily available, and now, so is the political drive. Given these drivers, the river water ought to achieve bathing quality in the near future.

Capital and technology for this solution are readily available, and now, so is the political drive. Given these drivers, the river water ought to achieve bathing quality in the near future. (Sunil Ghosh / Hindustan Times)

However, the single-minded focus on pollution of the river has resulted in a tunnel vision, where the critical issue of adequate flow in the river doesn’t attract similar fervour of action. The inadequacy of flow has, along with pollution and colonisation of the floodplains, destroyed many forms of riverine fauna and amphibians. While the Gazetteer of Delhi, 1975, listed 65 species of fish in the river, a recent survey found only four and that too stunted in size. Aquatic life needs both clean water as well as adequate flow and depth. For that matter, the cruises proposed along the Yamuna would also require both conditions to be met.

A massive volume of water is diverted into the West and East Yamuna Canals at Hathni Kund in Haryana, downstream of which the river becomes anaemic with only the water earmarked for Wazirabad (to meet the mandated level of 674 ft) flowing. The bulk of the water is abstracted at Wazirabad Water Treatment Plant, leaving little to flow downstream. The return water that contributes to the Yamuna in the city stretch is a mix of treated and untreated sewage flowing through 22 stormwater drains. It is important to note that the Yamuna flows in Delhi partly because most of the 360 million cubic metres of groundwater pumped out annually (amounting to nearly 100% of the groundwater draft) in the Capital is returned to the river, contributing to its flow. Near Okhla the waters are again diverted to the Agra Canal, effectively leaving a trickle downstream of Okhla Barrage. What is to be done to revive the flow? Here are a few suggestions for consideration by the decision-makers.

The Upper Yamuna Water Sharing Agreement will lapse this year. The riparian states will press for raising their share but the Union Jal Shakti (water resources) ministry must speak up for the voiceless river. The Upper Yamuna River Board can’t be a passive onlooker, monitoring allocation to the states but ignoring the needs of the river itself. While the present allocation of 10 cumecs to flow downstream of Hathni Kund, settled in 1994, is grossly inadequate, the National Institute of Hydrology’s recommendation of 23 cumecs, if implemented, can improve the flow in the river. However, this may not amount to environmental flow (e-flow) levels.

The Yamuna River Basin water budget must take into account irrigation demand, domestic and industrial requirements plus the scientifically determined minimum flow required to be left in the river, particularly from October to June. If values are estimated for the utilisation by various sectors, it will be apparent that demand management needs the maximum focus.

Clearly, irrigation efficiency should be taken up on war footing. The area between the Western and Eastern Yamuna Canals must be made the focus for this. Lowering irrigation requirements can reduce pressure on the river as well as on the aquifers, thereby enabling, in due course, improved groundwater base flow in the river. As irrigation efficiency spreads, the demand for river water can substantially fall.

National Capital Territory (NCT) of Delhi, too, can do its bit by implementing its water policy — dormant since 2015 — whose key recommendations are demand management and recycling. Thus, Delhi’s present water supply norm of 172 litres per capita/day (lpcd) ought to be gradually lowered to 135 lpcd. Demand management can be brought in through the large-scale application of aerated tap nozzles, and relentless pursuit of water efficiency which can save millions of litres daily through efficiency-rated water-based devices. The use of water-guzzling WC (water closet) systems should be banned. The use of herbal detergents can lower water requirements in laundry. The citizenry would have to be on board with significant efforts to improve hydrological literacy.

Recycling of treated sewage has immense potential although there are several complexities in its implementation. So far, Delhi has paid lip service to recycling when this should be taken up in mission mode. By 2030, Delhi should be able to recycle 440 million gallons daily (mgd), reducing its freshwater footprint massively. The reduced footprint would be in spite of an increased population. The saved freshwater would be allowed to flow in the river rather than be utilised by other riparian states.

In this regard, an evolving threat to Yamuna flow is emerging from Gurugram. Presently, Gurugram gets its water from the Yamuna through the Agra Canal and returns the used non-consumptive water to Yamuna through Najafgarh Drain. Now, Haryana is proposing to divert these waters for irrigation to Jhajjar. In that case, Yamuna stands to lose 400-500 mgd, resulting majorly in a dry Yamuna in the Delhi stretch. The ministry of Jal Shakti may take note and prevent this retrograde step.

Apart from flow issues, it may be pointed out that the river needs desilting. Much saprophobic, sludgy matter has also settled on the river bed, destroying bed habitats. All such matter must be removed from the channel. It is also recommended that the banks should have a wide belt of riparian grasses to stabilise the banks and provide habitats to various fauna.

A holistic approach that restores the river as an ecosystem, by focusing on water quality, adequate flow, bank and channel management, is the need of the hour.

Manu Bhatnagar is principal director, Natural Heritage Division, INTACH. The views expressed are personal