On July 19, less than a week after monsoon hit the Capital, several parts of the city were heavily waterlogged. Like many others, 27-year-old Ravi Chautala went to take photos of a waterlogged underpass in Pul Prahladpur. But he reportedly fell into the water and though fire brigade and divers were summoned to the spot, only his body could be retrieved from the waterlogged underpass. He left behind his wife and 10-month-old daughter.
Sadly, Chautala’s is not a lone instance. On the same day last year, a 56-year-old driver died in a waterlogged stretch under Minto Bridge where his van got stuck. These deaths have yet again exposed the national capital’s dirty secret: urban flooding.
Traffic moving at a slow pace through a waterlogged road at ITO in the Capital.
Lost in implementation
Despite the deaths, a Drainage Master Plan, commissioned nine years ago and largely seen as a solution, is yet to be implemented. It has now hit a roadblock of “data irregularities”, officials said. The last Drainage Master Plan of the city was prepared in 1976.
“At a meeting of the Technical Expert Committee last week, various departments said that the data used for the master plan was found to have several irregularities. A decision has yet to be taken on how to go forward,” a Delhi government official told The Hindu .
Experts said that while a range of problems with the storm water network is the major cause of the urban flooding, faulty sewage systems, rapid urbanisation, and climate change are intensifying Delhi’s woes.
The Drainage Master Plan for NCT of Delhi was commissioned by the Congress-led Delhi government in 2012 and a final plan submitted to the AAP government in July 2018 by IIT-Delhi. “The Chief Minister has directed the departments concerned to take concrete steps for the implementation of the report, which mentions in detail the specific reasons for waterlogging and flooding during monsoon,” an official statement issued by the Delhi government on August 1, 2018 on the master plan said.
NEW DELHI 27-07-2021: EDMC worker pumping out the rain water logged at Laxmi nagar Vikas marg using a pump set after the spell of rain , in Delhi on Tuesday. Photo SANDEEP SAXENA
It was then referred to a Technical Expert Committee, which is still going through the report. When contacted, R.K. Sinha, Member (River Management), Central Water Commission, who heads the committee, did not offer a comment.
Data irregularity
A.K. Gosain, Professor Emeritus of IIT-Delhi, who headed the team which prepared the master plan confirmed that the committee has flagged irregularities in data. “We used data which was given to us by various government departments to create the master plan. Now the committee asked departments to cross check 10% of the data with ground reality and in a large number of cases, the data given to us is not matching with the ground reality. This is not our fault. We had asked the departments many times to validate the data, but they never did it,” Prof. Gosain said.
The master plan submitted in 2018 had also warned of such a possible irregularity. “Since it is possible that many of the data elements that have not been independently validated by the respective departments may be different on ground than the digital reality captured and used in the model,” reads the master plan.
The last master plan was prepared when the population of the city was 60 lakh. Since then the population of the city has increased about four times. In the run up to the 2020 Assembly elections, Chief Minister Arvind Kejriwal had said that if re-elected then the government will make roads in Delhi like that of Tokyo and London in the next five years. But currently, many parts of the city go under with half an hour to one hour of rainfall.
NEW DELHI , 01/08/2021: A rickshaw puller and his fare struggling in flooded waters under the Shalimar Bagh railway bridge after a heavy spell of rain on Sunday morning, in New Delhi. Photo: SUSHIL KUMAR VERMA / The Hindu
‘World-class’ facility
On the day Mr. Chautala died in the waterlogged underpass, Mr. Kejriwal said that different agencies will make a “world-class” drainage system . “In view of the monsoon, a review meeting was conducted with PWD, MCD, DJB, I&FC chaired by the L-G on the drainage system of Delhi. Will implement a system like Minto Bridge at other vulnerable points. Drains and sewers will be regularly cleaned,” Mr. Kejriwal said.
The fact that drains in the city are controlled by multiple agencies, some by AAP and the others by BJP, makes the task more difficult.
Core problems
At the centre of the urban flooding problem is the state of both natural and engineered storm water drains. Storm water drains are supposed to carry the run off rainwater and empty into a waterbody, which in Delhi is river Yamuna.
Natural storm water drains are developed over the years as water naturally tries to find a way to flow and it depends on the terrain and slope of the land. In Delhi’s instance, many natural drains originate from the Aravalis.
“When you take an area for development, you engineer street-level drains, which will join the roadside drain and it will join larger drains. Usually, all these are flowing under gravity and flow into a natural drain. This will then drain out into a waterbody,” Mr. Gosain said.
Apart from this, there is supposed to be a separate sewage network, which is not connected to the storm water drain, and the sewage treated at plants. But in Delhi, sewage flows into the storm water network at many points and water in storm water drains, including Najafgarh drain (the largest), is blackish in colour and extremely polluted. Near Signature Bridge, where the about 10-metre-wide Najafgarh drain empties into the Yamuna, it changes the river’s colour to a darker shade and pollutes it.
Experts said the waste and sewage also reduces the water-carrying capacity of these drains. Adding to the problem, the rainfall has also become erratic. As global temperatures have soared, air has become warmer and it can hold more moisture, leading to more intense spells of rainfall.
“Studies have shown that in the last 3-4 years, Delhi has been getting intense rainfall in a short duration of time, which was not the case before. This is due to climate change,” said Kuldeep Srivastava, Head of the Regional Forecasting Centre of the India Meteorological Department.
For instance, between 6.30 p.m. on July 31 and the same time on August 1, the ridge monitoring station received 126.8 mm of rainfall. This is unusual for Delhi. “Though this is 24 hour data, most of this rainfall was received in a 3-4 hour window on July 31 night,” Mr. Srivastava said.
To contextualise, Delhi normally gets only 210.6 mm of rainfall in July. So, the ridge area got more than half of a month’s normal rainfall for the city in a matter of 3-4 hours in a day.
Stuck in paper
Mr. Gosain’s team, which took the help of over 900 students, inspected drains and collected data ranging from soil type and land use to rainfall and existing drainage network to come up with solutions.
The master plan gives a set of recommendations such as ‘no encroachment to be allowed on storm water drains’, ‘no sewage should be allowed to enter storm water network’, ‘design of new storm drains should not be done in isolation’, among others.
More importantly, the master plan used all the data collected to create a mathematical model which generated solutions for waterlogging problems in identified spots. The model generated four solutions — adjusting slope of the existing drain, diverting water to existing waterbodies, using additional storages, and other development works.
These solutions considered the rainfall, slope of the drain, and many other factors and were done with the larger picture in mind to provide a comprehensive solution to the city, rather than isolated ones. But they still remain on paper. “I’m disappointed at how things have progressed. Nothing much has happened after we submitted the report. If the departments give verified data to us, then the master plan can be reworked. But it will have to be done as a separate work,” said Mr. Gosain.
This year, the government has been able to prevent flooding at Minto Bridge, which floods almost every year, and has chosen six other points where short-term and long-term methods will be done. Manoj Misra, convener of Yamuna Jiye Abhiyaan, a civil society initiative for the river’s rejuvenation, said that looking at a handful of points will not solve the issue for the entire city. “The city needs a master plan and implementation of its recommendations,” he said.
“The DDA, in its 2041 master plan, has taken the matter of storm water very lighty. They have not addressed the root cause. This is the fourth master plan, what are you doing?,” asked Mr. Misra.
What is govt. doing?
According to the Public Works Department (PWD), which has the largest number of drains under its jurisdiction spread across the largest distance —1,954 drains covering an area of an estimated 2,054 kilometres — as much as 90,000 MT of silt was removed till July 19 this year.
While the PWD does not have a separate head related to expenditure on desilting, the process is part of the larger head of maintenance for which ₹37.27 crore was allocated in the year 2020-21 and ₹38.67 crore have been allocated for the year 2021-22, according to the Delhi government.
The average rainfall that the drainage network of the city can cater to, according to the PWD, is 50 mm per day; while rainfall in excess of 64.4 mm per day is categorised as “heavy” by the IMD, on July 14 this year, the city is said to have received between 85 to 100 mm of rainfall.
The department said it had set up the PWD flood control room on June 15 till the end of the ongoing monsoon, where live feed from ten locations were monitored around the clock. These include Minto Bridge, Sawan Park underpass, Tilak Bridge, Shakti Nagar underpass, Roshanara underpass, Azad Bhawan pump house, Pul Prahladpur underpass, Bhero Enclave underpass, Azadpur underpass, Zakhira RUB.
According to the department, there are four additional locations where CCTV installation is in progress such as the Moolchand underpass, Punjabi Bagh underpass, Badli underpass and the Shah Alam Bandh underpass.
While executive engineers have been deputed to monitor 147 locations vulnerable to waterlogging, the engineer-in-chief personally keeps an eye on seven critical locations. These consist of the Minto Bridge, Pul Prahladpur underpass, under Zakhira flyover, Loni Road Golchakkar, Jhangirpuri Metro Station Road, Karala Kanjhawala Road, Ring Road opposite WHO building.
At each critical point, according to the department, specific measures are in place to confront and tide over the issue of waterlogging. Minto Bridge has seen waterlogging in the past due to terrain and drainage issues; So, four CCTV cameras have been installed to monitor the situation in its vicinity around the clock along with a level sensor and a hooter to warn against rising water levels.
While an additional drainage line has been laid to divert discharge in drain along Minto Road towards JLN Marg as an interim solution, the only long term solution is the remodelling of the drainage network, for which the department said the appointment of a consultant for developing an alternate discharge line is in process.
Pul Prahladpur has, in the past, witnessed the discharge of big catchment area flows into the bowl shaped underpass and is monitored around the clock by seven CCTV cameras. At the moment, the interim solution has been putting in place an enhanced pumping capacity of 500 HP up from 450 in addition to the installation of 7 temporary pumps with a total capacity above 400 HP.
The installation of an additional underground pump with enhanced pumping capacity has been decided as a long-term solution.
