Bengaluru's story today; your city's tomorrow

Some years ago in Bengaluru, at the release of our report “Excreta Matters”, I got into a spirited discussion with the city’s water and sewage managers. The issue was the paradigm of water management in the city, which our research showed was unaffordable and so unsustainable. The engineers disagreed. According to them, they had managed to secure water from the Cauvery, being brought from some 100 km away through pipelines, and so had no reason to worry. They believed they had it all in control. Now as this hi-tech city hurtles towards a crisis of severe water scarcity, maybe, just maybe, these wise men will reconsider and rework their options.

The fact is Bengaluru is just another city that is being shown the mirror — the dream of perfect water driven by high-cost engineering solutions is going horribly wrong. And this, in an era of climate risks, where rainfall will become more extreme and more variable, is only going to get worse.
 

Bengaluru in the now distant past used to get its water supply from its vast network of lakes, designed to collect its rain and to mitigate floods. Then the search expanded, its first official water supply system was sourced from Hesaraghatta Lake on the Arkavathi river, 18-20 km from the city; then further to the T G Halli reservoir, 35-40 km away. But all this did not suffice and around 1974 the ambitious Cauvery Water Supply Scheme was conceived. By that, water would be pumped up to a height of some 490 metres and transported over 100 km. During my interactions with the city engineers, they were deep into stage 4 of this engineering marvel of a project and, as I said, they did not see any reason to worry.
 

I spoke of the cost of transporting water over longer distances. About a decade ago, the city required huge power to pump the city, which was eating into the fragile economics of the city’s water and sewerage board. Also as the distance increased, so did the water loss — a decade ago, these were roughly 40 per cent, according to official sources. All this meant the cost of the water supplied to people was going up, and the finances were precarious. But on the surface, all was well. The city boasted 100 per cent water supply to its citizens and, whatever the problems, Cauvery stage 4 would sort it out.
 

But I pointed out they were discounting the following facts. One was that groundwater usage was increasing in the city and its surrounding areas, which suggested that water supply was not so perfect. Two, the city was exploding and this expanding water-sewage infrastructure would be a pipedream and not keep up pace with growth. Three, most importantly, by their own admission, the bulk of the sewage generated was not being treated and this in turn was adding to the pollution in its intricate network of lakes and streams. But again, engineers were sanguine about the future. They boasted they had already built a sewage treatment capacity of some 720 million litres a day (MLD), using every available technology possible. This technically would be able to treat almost all the sewage generated. But when I pointed out that less than half the capacity was being utilised, they told me it was only a matter of time. Very soon the pipeline network would expand and all would be well.

Now, let’s cut to today. In 2010, the city’s water requirement was estimated at some 1,125 MLD, and that has more than doubled to 2,600 MLD. And while the Cauvery still supplies half of it, the rest is now from groundwater. In other words, the explosion of demand has remained unmet and people have had no option but to dig and dig deeper to secure their water. With increased variability of rainfall, these sources are drying up, and fast. But the pipedream sellers have not understood the crisis — the city’s chief water manager is now banking on the fifth stage of the Cauvery project, which will be commissioned, he says, very soon and this will end all water worries.

The sewage story is similar. Infrastructure was more than doubled. According to the Central Pollution Control Board’s 2021 inventory, the city now has a sewage treatment capacity of 1,668 MLD and another 425 MLD is under construction. But capacity utilisation remains stagnant at 50 per cent — and so in other words, more sewage is being intercepted but as water needs have doubled, so has sewage generation and still the bulk is not being intercepted and not being treated. But again, speak to the engineers and they will tell you that it is only a matter of time when all will be well. All the homes will be connected, sewage intercepted and taken to treatment plants, and discharged clean into rivers, which will be miraculously transformed.

This is the real crisis of our water planning — the inability to understand the need and the opportunity for the change in the way we do this water-waste business. This is what needs to be punctured — for good. The fact is Bengaluru has enough rain; it has lakes that can recharge this water; this can make its groundwater secure so that even in times of extreme rain events its rich and powerful denizens do not have to swim to avoid drowning in the flood. Every drop can be used for the coming period of scarcity. Then it can do its sewage differently. Instead of believing that it can transport sewage with pipelines, it can ensure that every drop of excreta is collected by tankers and then treated and reused — once again by using the same lake infrastructure to recharge. But for this water engineers have to come down to earth and rework and rethink water futures. This is not just a Bengaluru story; it is theirs today and yours tomorrow.

The writer is at the Centre for Science and Environment sunita@cseindia.org, X: @sunitanar