As Hyderabad grapples with extreme rainfall and floods, it should draft a long-term mitigation plan

In the 2022 monsoon season, July turned out to be the wettest month in the city of Hyderabad. The city, the joint capital of Telangana and Andhra Pradesh states recorded excess rainfall of 144.2 millimetres against the average of 38.1 millimetres.

The rainfall was particularly heavy during the week of July 6-13, with torrential rains lashing almost the entire Hyderabad and its outskirts. From June 1, starting with the pre-monsoon showers the city received a high of 511 mm rainfall upto August 1, which is 218 millimetres higher than the average for the entire monsoon season, according to data from the Telangana State Development Planning Society.

The volume of rainfall on July 26, ranged between 6 centimetres and 10 centimetres in just two hours around midnight. It left people in several areas struggling with water logging, inundation, overflowing drains. Fluctuating power and outages further aggravated the situation.

Homes were flooded with rainwater and sewerage mixed and thousands of people in areas such as Padma Colony of Chaderghat, Ayyappa Colony in Nagole, Kodandaram Nagar and Saraswathi Nagar in Saroornagar, and certain locations of Malakpet, LB Nagar and Dilsukhnagar, were affected.

Usually, September was the month when the city received heavy rainfall. But in recent years, heavy rainfall has been occurring at any time in the southwest monsoon season from June to September.

Among the worst extreme weather events in the city in recent years was the record-breaking rainfall (192 millimetres during October 13-14) and consequent floods in October 2020, which left nearly 50 dead and destruction estimated around Rs 5,000 crore.

Hyderabad and neighbouring areas have reported extreme rainfall spells of between 15 and 24 centimetres in a single day on four occasions in the last decade – July 2012, September 2016, September 2019 and October 2020.

Before that, the heaviest downpour was 24 centimetres in 24 hours in August 2000. With this increasing frequency of episodes of extreme rainfall, the river Musi, considered nearly dead has come alive and started to overflow at some point and submerging low lying areas.

While extreme weather changes continue on one hand, on the other, Hyderabad city continues to grow rapidly. Specially over the last two decades, with high rise corporate and residential buildings, flyovers, the metro rail and upcoming ring roads bring with them, arise in traffic, population and waste generation.

Cyberabad, the area of Hyderabad which hosts major global technology companies, has has large residential complexes but not a well-planned drainage system, according to experts.

This urbanisation and transformation, though impressive in external appearance has neither been very planned nor with a definite vision. Consequently, Hyderabad is fast losing its natural courses of rainwater drainage system that were the cornerstone of a visionary plan by engineer Mokshagundem Vishveswarayya in the early 20th century.

Moved by the large scale destruction and death of thousands in the September 1908 Musi river floods, the Nizam Osman Ali Khan had specially sought and got the engineer to formulate a long term plan. As per the plan, two large reservoirs, Osmansagar and Himayathsagar were created in 1911.

A network of storm water drains were connected and the dozens of lakes supplemented in ensuring that the rainwater did not flood any areas of human habitation but ran their course into the river.

Climate change effect

The impact of climate change is manifesting in the form of an increase in the episodes, and in some cases intensity, of extreme weather incidents, especially heavy rainfall in cities across India.

“Both the Bay of Bengal and the Arabian Sea which influence cyclonic and other atmospheric events have witnessed a rise in warming over the decades. This in turn is triggering cyclones, floods and heavy rainfall across the central and south India covering over 50,000 sq kms,” says Raghu Murtugudde, a visiting professor at the Indian Institute of Technology, Mumbai, and Emeritus Professor at the University of Maryland in the United States.

“The erratic distribution of rainfall during the southwest monsoon period is also due to global warming. Instances of heavy downpour of over 150 mm per day are typically characterised as ‘extreme rainfall events’,” he explained.

“The SW [southwest] monsoon is also pronouncedly effected by El Niño or La Niña factors. This year the latter has been strong from May and the rainfall fluctuations can be attributed to it,” says K Ashok, a professor at the Centre for Earth, Ocean and Atmospheric Studies at the University of Hyderabad.

According to the India Meteorological Department, 2022 has seen the second highest occurrence of extreme weather events in the last 100 years. In March, the country experienced the highest temperatures in some parts of north India.

While in cities, these weather events take a toll on urban infrastructure, business and everyday life, in rural areas the changes in the rainfall patterns could have a long term impact on the farming operations during the kharif season, especially in those areas dependent on monsoon rains only.

Forecast, being prepared

The India Meteorological Department has been improving its forecasts of weather and rainfall over the years. It has set up Doppler Radars that give precise data for forecasts. These radars send electromagnetic waves to the rainbearing clouds and the sensors record the intensity of the rain bands. The data is then analysed to provide forecast of rainfall.

In Hyderabad however, the only Doppler Radar located at the old Begumpet airport, was not functional for over a month during the June-July period.

In the absence of the radar, the weather department used other forecasting tools such as light observation, synoptic charts, models and radars from other places, said K Nagaratna, Director of the India Meteorological Department, Hyderabad.

“It’s a tedious process, looking at all these radars, but we’re making sure the forecasts are correct. If our [Doppler] radar is operational, it will be simple for us to provide forecasts,” she told the media.

While the India Meteorological Department is well-equipped to make timely and accurate forecasts of urban rains, it has not divided the urban areas into met sub-divisions as suggested in the guidelines of the National Disaster Management Authority, says Marri Shashidhar Reddy, a former legislator of Secunderabad.

“We suggested watersheds or nalas as sub-divisions. In the case of Hyderabad, we will then have 13. The Doppler Radar can easily give precise rainfall date at these points, which in turn will help the disaster management and local body to swing into action,” Reddy, who was also the former Vice-Chairman of the National Disaster Managment Authority explained.

Lessons from 2020

The extreme rainfall event of October 2020 comprehensively exposed the unpreparedness of Hyderabad in handling heavy rains.

With a network of 165 lakes and 13 storm water drains, as well as the Himayatsagar and Osmansagar reservoirs, Hyderabad has a natural solution to absorb large quantities of rainfall and prevent flooding.

However, construction of structures on the nalas, mix up of sewage lines, insufficient desilting before the monsoon and concretisation that stops the water from draining are all making the city more vulnerable to flooding.

In the name of beautification of the city, the basic conservation mechanisms are being sacrificed, which will have a bad effect in the long term, warned D Narasimha Reddy, a noted environment and development activist.

In fact, the lakes, which were a blessing were turned into a curse due to bad management and unplanned growth and expansion of the city. Instead of controlling floods, they are causing floods in low lying areas as their course has been obstructed by concretisation and spread shrunk by land grabbing, he alleged.

“We are still reacting to disasters in a knee jerk manner. Rescue, Relief and Rehabilitation (three ‘Rs’) is the mantra. Never heard of a disaster management authority, discussion or meetings on tackling disasters in Telangana government’s Municipal Administration Department,” laments former legislator Shashidhar Reddy.

The three city departments – Urban Development, Metro Water Works and the Greater Hyderabad Municipal Corporation have not been adequately strengthened with capacity to take preventive measures like timely forecasts, evacuation and desilting. Therefore, only once the disaster kicks in, do they jump into action., says Shashidhar Reddy.

Possible solutions

Most experts warn that unless a long term disaster mitigation plan is put in place and timely, preventive measures are taken, Hyderabad’s growth and image as a good destination for investments and living will be in jeopardy. It will be forced to resort to very expensive solutions like creating underground storage spaces or reservoirs – difficult given the rocky terrain.

However, a set of urgent steps that experts have suggested, to remedy the situation, are prevention of further encroachment of water bodies; better planning of drainage system in the concrete zone of Cyberabad, which is fast expanding; rehabilitation of people living in low lying and catchment areas of lakes and nalas and improving the forecast and alert system of the India Meteorological Department tailored to cities.

A round table conference organised by Justice Subhashan Reddy Memorial Foundation towards July end on “Mitigation of urban floods and the way forward” came up with a set of recommendations.

These include: set up a State Disaster Management Authority, Implement the National Disaster Management Authority guidelines on urban flooding and follow the storm water drainage manual of 2019 and prepare a Monsoon Distress Index for citizen-centric disaster management plan.

This article was first published on Mongabay.