Hope turned into disappointment for Chennai when Cyclone Phethai, which brought the promise of rains, headed north for the Andhra coast on Monday. With less than two weeks for the end of the Northeast monsoon, rain-starved Chennai is staring at a possible water-deficit summer in 2019. According to the Indian Meteorological Department (IMD), as of Tuesday, Chennai has a rainfall deficit of 54% this year. This means that the city is likely to witness a repeat of the summer of 2017.
The shortage of rainfall this season has threatened to dry up the four lakes in the outskirts of Chennai -- Poondi, Cholavaram, Redhills and Chembarambakkam -- which supply drinking water to the city. As of Tuesday, the water level in Poondi lake stood at 0.35 tmcft as against its full capacity of 3.23 tmcft while the water level in Cholavaram lake stood at 0.05 tmcft as against the full capacity of 1.08 tmcft. Water levels at Redhills stood at 31.57% of its total capacity, while the water capacity of the Chembarambakkam lake is at a mere 3.57%.
With levels already dangerously low in some of the lakes, how does the government into tackle the impending water crisis?
Drinking water needs of Chennai
On any given day, Chennai requires 850 MLD (Million Litres per Day) of water. The Chennai Metro Water Supply and Sewerage Board (CMWSSB) presently supplies around 650 MLD. The CMWSSB meets this demand by drawing water from the four lakes, desalination plants, agricultural wells etc and supplying it to residents.
During the summer season this supply drops to 450 MLD, said a senior official from the CMWSSB to TNM.
The situation this year is similar to 2016, when the monsoon failed the city. In 2016, Chennai received 342.1mm of rainfall against the normal rainfall of 789.9mm of rainfall from October to December. This was a shortfall of 57%. In January 2017, Tamil Nadu Chief Minister Edappadi Palaniswami declared the state as âdrought-hitâ, calling it the worst in 140 years. The following summer between April and June 2017 was one of the worst Chennai had witnessed.
Speaking to TNM, Vishnu V, the former Executive Director of CMWSSB who was in the organisation during the summer of 2017 said that apart from putting their heads together to meet the supply demands of the city, the Board also worked to curb the demand for water.
âWe ran the desalination plants in the city at full throttle which enabled us to tap 200 MLD of water. We also introduced âDial for waterâ method by which domestic users can book water to fill up their tanks. We put a cap of five days for such bookings and several internal control mechanisms like unique consumer ID were in place to prevent duplication and exploitation among the domestic consumers,â he recalled.
It was in 2017 that the CMWSSB also sourced water from abandoned quarries for the first time. âFor the first time we identified quarries in Kanchipuram district, especially in Sikkarayapuram, which had stored a lot of water from the 2015 December rains. So, we devised a method to pump out water from those quarries, treat it and supply it to the city. We also cut down water supply drastically to the industries in Chennai and focused on meeting the water requirements for domestic usage,â Vishnu said.
Plan for 2019 summer
While Chennai Metrowater intends to repeat a number of these measures, it has also started work to ensure that the city does not run dry during the 2019 summer. Speaking to TNM, a senior official from CMWSSB said that identification of new quarries and lakes will help cater to the cityâs water needs.
âFor the coming summer, we have identified a new quarry in Erumaiyur in Kanchipuram district to tap water from. We are laying pipelines from Erumaiyur to Chembarambakkam water treatment plant to make the water from the quarry ready to be supplied to the city. Apart from that we had surveyed 13 lakes around the city for drawing water and have now identified three lakes out of them which can be used to draw water during summer,â he said. He also added that the old method of operating the two desalination plants at full capacity will continue this season as well, to meet the demand in Chennai.
When asked if the water-situation at present is as bad as it was in 2016 December, the official admitted that it is worse than 2016 but added that the chances of dealing with the crisis is much better now. âI personally feel that we have more sources of water now than we had in 2017 because we will have water from Veeranam reservoir (which gets water from Mettur dam) due to resolution of Cauvery water dispute and the water level in Kandaleri reservoir (a part of the Telugu Ganga project, which receives water from river Krishna) is slightly better than what it was in 2017. So I think we will be able to manage the situation this year as well,â he explained. He added that once the monsoon season is officially over, all the restrictions on usage that were put in place by the CMWSSB will be back.
Chennai needs long-term strategy and not short-term ones
However, experts like S Janakarajan, Professor and Officiating Director at Madras Institute of Development Studies pointed out that Chennai has in the past had a water crisis inspite of a good monsoon.
âChennai does not have a long-term strategy to deal with water crisis. We solely depend upon two or three reservoirs and we think that we are well off to deal with summer season,â he said.
Explaining that the city does not have proper rainwater management and harvesting mechanisms, he said that the groundwater table has not been recharged. âIt is not because of the lack of rainfall that we suffer, it is because of lack of mind, lack of commitment, lack of ideas that we suffer,â he added.
Professor Janakarajan stated that there are 3,600 water bodies in Kanchipuram, Chennai and Tiruvallur districts and that the number will be 4,100 if those in Arakkonam are included. But inspite of the numbers, most waterbodies are bone dry even during years of good rainfall due to lack of rainwater management mechanisms.
Arguing that drawing water from desalination plants are only a temporary measure, he added, âYou think desalination plants will save the day? The plants are killing the marine ecosystem in the process of supplying water to the city.â