A drizzle and waterlogging, that’s monsoon Delhi

In the National Capital Territory (NCT) of Delhi, every time it rains, it floods. This year has been no different in spite of a spate of new measures — new master plans for drainage and sewerage systems, a new flood control order, frequent directives from the Delhi High Court and several monitoring and coordinating agencies put in place at different levels to monitor and prevent urban flooding.

The entire capital city is prone to frequent flooding due to rain, but the only agency that maps the particularly vulnerable spots is the Delhi Traffic Police. The 2018 Drainage Master Plan for NCT, prepared by a team from Indian Institute of Technology Delhi led by noted hydrologist A.K. Gosain, points out that various other civic agencies responsible for managing storm water drainage are neither mandated by law nor bother to keep a record of the extent of flooding. The Delhi Traffic Police records have 330 areas prone to flooding, including 156 identified for this year so far. They are spread all over the city.

The apathy of the civic bodies, and there are nearly a dozen of them, is so glaring that in spite of constant supervision and reprimands for nearly two decades by the Delhi High Court, it had to step in again this year, seeking immediate “emergency efforts” as the first rains hit in July. It appointed a panel under the CEO of Delhi Jal Board (DJB) for remedial measures and again lamented how multiplicity of authorities and their inability to perform the minimal task of ensuring proper drainage are adding to the citizens’ woes and bringing life to a standstill.

What needs to be done to prevent such flooding is well known. The 2018 Drainage Master Plan reiterates those: (a) correcting faulty drainage infrastructure — majority of drains flow in a direction opposite to the natural flow of water, and in many cases big drains merge with smaller ones; (b) adopting low-cost flood preventing measures such as rejuvenation of water bodies, rainwater harvesting and low-impact development options and; (c) delinking of solid waste and sewage drains from storm water drainage to prevent clogging and pollution.

“The same challenges, however, persist,” a senior Delhi government official lamented. “It is obviously an implementation issue which is being neglected by almost every civic agency responsible for managing the affairs.”

Broken drains

Delhi’s storm water drainage infrastructure is in a dilapidated state, says the IIT Delhi report. The last drainage master plan was prepared in 1976, when the population was 6 million. It has gone up more than three times and stood at 16.7 million in the 2011 Census. It is now estimated to be around 20 million.

Delhi has 426.5 km of natural drainage lines and 3,311.5 km of engineered storm water drains. These are under the aegis of 11 different agencies — Department of Irrigation and Flood Control, Public Works Department, South Delhi Municipal Corporation, North Delhi Municipal Corporation, East Delhi Municipal Corporation, New Delhi Municipal Council, Delhi Development Authority, Delhi State Industrial and Infrastructure Development Corporation, Delhi Cantonment Board, NTPC Ltd and Uttar Pradesh Irrigation Department.

The multiplicity creates a coordination challenge and everybody passes the blame every time roads gets waterlogged, no matter what the Delhi High Court and National Green Tribunal (NGT) say.

Design flaws

To begin with, there are major design flaws with the existing drainage system. A majority of the storm water drains have wrong gradients or slopes — which takes the water away from its natural downstream flow — in all the three major drainage basins: Trans Yamuna, Barapullah and Najafgarh. As a result, the collected runoff has to be pumped back into the Yamuna or drains joining it every time it rains. A failure of these pumps is an annual occurence and so is waterlogging. Another design flaw is that larger drains flow into smaller ones, which causes congestion in the system.

Rapid unplanned urbanisation, increase in paved surfaces preventing water percolation, dumping of construction debris and garbage in drains, covering of drains by building ramps, parking lots and markets that prevent cleaning, and mixing of sewage drains with storm water drains are some of the other major issues. Rapid urbanisation and encroachments have claimed 18 major drains of Delhi between 1976, when the last drainage master plan was made, and now. In 2014-15, the NGT had asked the Irrigation and Flood Control Department (I&FC) of Delhi to trace 201 major drains listed in the 1976 master plan. As of now, it has found only 183.

Three drainage basins

The three drainage basins have different defining features. The Trans Yamuna basin has shallow groundwater level and low elevation, which makes it prone to flooding. The region is protected from river flooding by two marginal bunds (embankments) but ironically these very bunds prevent any rainwater runoff into the river.

The Barapullah basin also has shallow groundwater level and low to medium elevation. The region is protected by a check dam in Mehrauli to prevent surface runoff from Haryana. The Najafgarh basin, the largest of the three, has major drains such as Najafgarh and Mungeshpur that carry considerable storm water from outside Delhi. In all these basins, mobile pumps are used to pump out surplus water into nearby drains when needed, causing congestion in the drains and flooding downstream areas.

Though the 2018 master plan is a good first step, a solution is far away. IIT Delhi, which prepared it, says it has only “quantified for every drain as to what is the surplus runoff that needs to be handled using various mechanisms” and that it has “deliberately not provided the complete implementation strategy”. That is the job of the civic bodies.

Shiv Kumar, chief executive engineer of the I&FC, which has been appointed the coordinating authority to implement the master plan, says the next task is for Geospatial Delhi Ltd (GSDL), a Delhi government undertaking, to explore the flooding points, after which the civic bodies will validate the IIT Delhi’s models with ground observations. After this is done, an implementation strategy will be worked out.

That’s the theory. In practice, after IIT Delhi submitted its draft master plan in 2016 and asked for such validation before finalising its report of 2018, only two of the 11 civic agencies have responded so far — North Delhi Municipal Corporation and I&FC.

Disappearing water bodies

The Drainage Master Plan of 2018 shows that water bodies can play a major role in reducing flooding. The plan’s simulated modelling for all three major drainage basins show that if, after correcting the faulty drainage design, excess runoff water is routed into nearby water bodies (in 100-150 metre range) flooding can be significantly controlled.

“Our calculations have shown that flooding of the Trans Yamuna basin can be reduced by about 90% if we utilise water bodies in the area after correcting the invert levels of drains,” Satish Kumar, IIT Delhi scholar and a member of Gosain’s team who handled the task of data crunching and modelling for the drainage master plan, told indiaclimatedialogue.net. “If we add public parks to water bodies for accommodating excess water, then we can achieve the same result (90% reduction in flooding) for the Barapullah and Najafgarh basins too.”

While the water bodies are important in Delhi’s scheme of things, the large number of civic bodies responsible for their upkeep — Department of Revenue, I&FC, DDA, Department of Archaeological Survey, Department of Forest, CPWD, PWD, the municipal corporations and IIT — have shown little interest. A 2016 report of the Parliamentary Standing Committee on Water Resources made some shocking revelations. Of the 971 identified water bodies of Delhi, 346 are dry, 321 are wet, while 215 are fully encroached upon and 89 have been converted into parks.

Pathetic state

Describing it as a “pathetic state”, the parliamentary panel observed that “lack of enforcement of the existing laws and poor maintenance of land records in both the rural and urban areas have resulted in rampant encroachment.” A similar concern had been expressed by the NGT in the same year (2016), following which a high-level committee under Delhi’s Public Works Department minister Satyendra Jain was formed. But today, the nodal agency for water bodies, the Delhi Parks and Gardens Society of the Delhi government, has no record to show what work has been done for the upkeep or how many water bodies have been revived or preserved.

Earlier, the Delhi High Court had ordered a physical verification of water bodies in response to a public interest litigation filed by Tapas, a non-government agency. The verification process began in 2005 but remains inconclusive, with no clear idea about when will it end.

Arvind Sah, the Court Commissioner appointed to oversee the exercise, declines to say how many surviving water bodies have been found, on the ground that the counting exercise should be completed first. But, “Almost all water bodies, except those in southwest Delhi and other less inhabited areas, have been reduced to dumping ground of sewerage, construction debris or encroached,” Sah told indiaclimatedialogue.net.

Lack of application

Sah flags off lack of sensitivity, training or application of mind by the officials of various civic bodies as big challenges to the survival of Delhi’s water bodies. This is best reflected in the restoration work of the Old Fort Lake in New Delhi, less than 500 metres from the Delhi High Court.

The Old Fort Lake was a popular destination for boating. The National Buildings Construction Corporation (NBCC), a central government undertaking, was given the task of restoration after it went dry a couple of years ago. The NBCC has already concretized the embankments and paving them with stones.

A part of the bed has been covered with perforated geo-textile sheet to prevent percolation. This display of gross insensitivity to the historical context of the lake and ignorance of environmental friendly alternatives has so angered the environmentalists that some of them are seeking legal remedies.

Though no comprehensive picture is available, it is known that the state of some of the water bodies is a cause of serious concern. The Bhalswa Lake is now filled with sewage water. The Jahangirpuri marshes have been encroached upon. The Najafgarh Lake, which can be a good source of water for domestic consumption, has turned into a sewage dump. In response to the NGT’s directive, Delhi and Haryana governments agreed in 2017 to revive the Najafgarh Lake but there is no sign of any action yet.

Manu Bhatnagar, principal director of natural heritage division of Indian National Trust for Art and Cultural Heritage (INTACH), told indiaclimatedialogue.net that the trend towards extinguishing water bodies got accelerated with the economic liberalisation of 1991 when GDP growth became the sole benchmark of economic development and water bodies acquired real estate value. Moreover, as tube wells and toilets came into their lives, villagers had less stakes in the survival of water bodies around them.

There are, however, a few positive cases of revival and preservation. The Hauz Khas Lake has been revived with INTACH’s efforts and has become a habitat for migratory birds and a popular destination for reidents from all over Delhi. The Sanjay Lake, an artificial water body developed by DDA, is well preserved and so is the Naini Lake in North Delhi. The threat, however, far outweighs such gains.

Inadequate sewage infrastructure

“Presently, approximately 50% of Delhi is not connected with sewerage system…,” says the Sewerage Master Plan for Delhi 2031, released in 2014. That means the sewage generated by 50% of the population, including those from unauthorised colonies, flows into storm water drains.

A top official of Delhi government, who wished to remain unnamed, said almost all drains in the capital, except for some falling under the jurisdiction of NDMC, carry sewage and storm water together, a fact also confirmed by a member of the IIT Delhi team, which prepared the drainage master plan.

Sewage, along with garbage dumped on the roadside drains, leads to silting and blockages in the drains, which requires annual cleaning but this is seldom done in time or properly. The DJB, which is in charge of sewage disposal, punctures sewer lines and drains sewage into storm water drains — a practice the IIT Delhi forbids in its recommendations. In case of congestion, it advises DJB to using latest mechanisms such as super suckers for de-clogging the sewer lines.

According to the Sewage Master Plan, Delhi generates 680 million gallons per day (MGD) of sewage, 50% of which is untreated and discharged into the Yamuna. It has 34 wastewater treatment plants (WWTPs) with an installed capacity of 594.7 MGD but with utilisation of 57%, which brings down the actual capacity to treat to only 339 MGD. This data is from 2011. A 2015 report of the Central Pollution Control Board said that 60% of the sewage generated in Delhi was untreated and discharged into the Yamuna.

Given the enormity of the challenges, the Sewage Master Plan proposed an Interceptor Sewer system as a short term relief measure to trap the sewage, which is being tried at present. Laying out the sewage network for 50% of the capital city is a long haul for which the DJB has displayed little appetite until now.

So the capital’s citizens should expect their plight to continue in the foreseeable future. Until the bureaucrats get their own act together, every time it rains, expect waterlogging and worse.