A phoenix from the drought? Chennai to reignite desalination
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A phoenix from the drought? Chennai to reignite desalination

Thursday, 4 July 2019

Severe drought is forcing the country to re-evaluate desalination and bring plans for a third desalination plant back to life in Chennai…

Indian City Chennai to speed up desalination roll out amidst desperate drought

Facing one of the worst water crises since 1987, the Indian City of Chennai is looking to reignite stalled plans for additional desalination capacity.

Rising like a much-needed phoenix from the drought, the Nemmeli II desalination plant is back on the table after the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) issued a letter of award.

Tecton Engineering, together with Cobra will develop the 150,000 m3/day desalination plant after reported legal battles had nearly taken the project back to the drawing board after being planned in 2013.

According to GWI, Nemmeli II is commissioned for 2021-2022 and the new project will augment the 100,000 m3/day Minjur and 100,000 m3/day Nemmeli I plants.

The CEO of Tecton Engineering, M Subramaniam was quoted by GWI as saying: “The only long-term sustainable option for Chennai is desalination combined with prudent water reuse.”

Quenching Chennai’s thirst

A much larger fourth desalination project with a capacity of 400,000 m3/day is also on the cards in Perur, after funding was confirmed by the Japan International Cooperation Agency (JICA) over one year ago.

Project consultants are expected to be selected next month with the project tender floated by the end of 2019, the Hindu reported.

Not slated for operation until 2025, this would be a long-term solution for a city that is desperate for water in the short-term.

Even the two operational desalination projects in Chennai currently supplying 180,000 m3/day are only meeting 20 per cent of the city’s growing water demand.

To put it into perspective, CMWSSB estimates it is only able to supply 530,000 m3/day of water but the city needs around 900,000 m3/day.

To quench the city's current insatiable thirst, a series of much smaller, modular 5,000 m3/day desalination plants could be used in the short-term.

Chennai’s desperate drought situation

So how did Chennai’s drought become so bad? As is often the case with severe drought and limited water reserves, it's a case of multiple factors all coming together in a perfect storm of events.

A weak North East monsoon season at the tail end of last year has meant the four major reservoirs serving the city continued to be abstracted without ever being replenished.

This has been coupled with one of India’s longest heat waves, with temperatures reaching 48 degrees Celsius in mid-June, killing at least 137 people in the process, according to CNN.

The quadruple whammy of unsupervised overexploited groundwater, double-digit population growth, limited rainfall and poor water management have collectively fast-tracked the city to a desperate drought situation.

State water trucks are now shipping water into the city. Each morning millions line up to fill up a collection of pots and cans with some residents getting their rationed quotas of water per daily, others per week.

However, reports suggest due to the sheer demand, truck operators are selling the water at high prices, making it difficult for poorer residents and inaccessible for those living in slums.

Images below from Maxar Technologies, provided by the Copernicus Sentinel-2 Satellite, show the Puzhal reservoir in Chennai before and after the drought (Image: AP).

India’s man-made water crisis

Nor it is just in Chennai where India faces severe water problems. A study from government think tank NITI Aayog predicted that 21 India cities will run out of groundwater by 2020.

While it would be easy to label the Chennai water crisis as a barometer of climate change, an article in Bloomberg Opinion said it is “largely a man-made disaster – one that more Indian metropolises are soon to suffer no matter the weather”.

Another reason is urbanisation.

Located on a flood plain, by paving over wetlands and lakes Chennai has in the process created a man-made barrier to the natural process of water table recharging. Less than four years ago the city was inundated by devastating floods.

Others believe a 'lopsided procurement system' is to blame and groundwater depletion is linked to "the promotion of rice and free electricity”. Water-intensive crops such as rice and sugarcane are extensively grown in areas with poor rainfall, such as Punjab and Gujarat.

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