The Perils of Over-Dependence on Cauvery for Drinking Water

The beautiful Cauvery river originates in Talakaveri in Kodagu and meanders through a scenic 805 km route in Karnataka and Tamil Nadu before meeting the sea. It is often referred to as Cauvery Tayi or mother because of its significance in the lives of the people of Karnataka. From irrigation to power generation to drinking water, the river gives selflessly. For Bengalureans, it is an important source of drinking water for its one crore plus population that is growing steadily. But the question we need to ask ourselves is, are we doing a great disservice to the river as well as the people in the rest of Karnataka by over-exploiting the Cauvery for drinking water?

Bangalore consumes about half of the Cauvery water reserved for domestic use in Karnataka. As Bangalore’s population spikes, this demand is only going up. The time has come for us to look at ways to wean ourselves away from our overdependence on the Cauvery.

Firstly, using the river to supply water to the city of Bengaluru may not be the best use of the river. As of now, Bengaluru gets about 810 MLD of water from Cauvery. Out of this, close to 50 per cent is lost in distribution, given that it travels such a long distance to reach Bengaluru. Bengaluru is spending an estimated ₹ 350 crore every year to pump Cauvery water for over 100 km to reach the city. This does not include the social and economic cost to farmers in the Mysore/ Mandya region. Given this, it is clear that this water can be put to much better use if used for irrigation purposes.

Secondly, over-dependence on Cauvery is not good for the people of Bengaluru either. One bad monsoon that affects the river can plunge the city into crisis mode since it loses its biggest source of water. Besides, there is a limit to how much of Cauvery water can be supplied to Bengaluru. Given the way that the city’s population is rising, Cauvery will not be able to meet the demand for long.

What’s the Alternative to Cauvery for drinking water?

The most pragmatic solution to Bangalore’s water problems lies in effective rainwater harvesting. Bengaluru receives an average of 830 mm of average rainfall per year. If harvested correctly, this water is actually sufficient to fulfil a majority of the city’s water demand.

The second part is to do with large scale wastewater treatment such that this water can be stored in lakes and reused. According to a study by ATREE on ‘2035 Vision for Water and Wastewater in Bengaluru,’ pumping treated wastewater into lakes would also ensure that lakes in the city do not dry up. This means that existing Sewage Treatment Plants (STPs) in the city need to be used to their full potential, and several more need to be added.

For many centuries, Bengaluru never had any perennial source of water. The early residents of Bengaluru had addressed this issue by building a large network of lakes that helped meet the city’s water requirement.

If we make real efforts to save and revive our lakes and at the same time, invest heavily in rainwater harvesting, we can easily find ways for Bengaluru to be self-sufficient in terms of drinking water. This way, we can even empower our farmers in Mysore and Mandya through better irrigation.