S1Extra8: Our Path to Water Resilience

Arpita: As I began wrapping up my chat with S.Vishwanath of Biome Trust on water management and rain water harvesting systems within cities, it guiltily occurred to me that I myself wasn’t doing a great job of harvesting rain water within my house. Instead of collecting our rain water we had diverted the pipes from our terrace to flow not into the drains but instead to flow over the lush green backyard we are lucky enough to have in this concrete city. When I was listening to him I just felt that there was more I could easily do. But where could I possibly begin?

Considering this simple question made me realise that many of us don’t have our own houses to tinker with. And what if we are just about to build a house? Well to clarify all this and more, I decided to do a quick FAQ with him about how more of us can work towards improving the holistic water resilience of our cities.

Arpita: So let’s begin with what do you do if you already have a house but it does not have a RWH system?

Vishwanath: So the simplest thing that can do with rainwater harvesting is to pick one pipe which comes down from the roof bringing down rain water and stick a drum below it. Now if you stick a 200-liter drum below this pipe, chances are they can fill up 50 times in a year. If you emptied it every time it fills up which means: 50 into 200 that’s 10,000 liters of water saved. Just takes one 200-liter drum to generate 10,000 liters of water. The moment you begin you’ll see that your whole attitude to the process changes. What was completely wasted as a resource and was completely ignored, now when the drum overflows you see like what am I wasting that water? Once your attitude changes, then you’ll figure out how to store more or recharge more.

A classic example is working with a big company. Where we had to justify the building of a 50,000 liter sump tank based on rainfall for daily rainfall for 28 years 30 years. The first rain the thing overflows and the immediate question is why did you build it so small? For six months, the question was why are you building such a large 50,000 liter storage tank? It is never going to fill up. One rain and it was why did you build it so small. Now we’re wasting water, we need bigger. The moment your attitude to the resource changes, then you find solutions, but what we have as Indians, especially is a starting problem. We intellectualise an idea and we’re not able to translate into practical action. Thing is to stick that 200 liters drum. Once you do that you start to figure out how much water you’re getting and how you’re benefiting. Then slowly you can expand to connect all the other remaining pipes. Never think hundred percent think 30%- 40% and how to build on it to reach a 100%. Once you do that, everything will change for the better and that’s rain water harvesting.

Arpita: Got it! Must make a beginning however small. But what if I am constructing my house and can think ahead on this – how do I add in RWH systems within the house design?

Vishwanath: So most probably when you are building a house, you would have a sump tank. Sump tank is being built for you to store water which you buy from a tanker for building your house or you would have a borewell to be using water to build your house. Make sure that when you do the roofs of your house you slope it in the direction of the sump tank or the borewell. Get your rainwater pipes which bring down the rainwater from the terrace in that direction. Then place a filter in each one of these down pipes. Typically you won’t need more than two downpipes. So you’ll need two filters. The filters, you can buy it from the market or you can make your own using a 60 liter drum and filling it with gravel and sand. Once you’ve filtered the water lead it into your existing sump, you don’t have to create a new one. Or make a recharge well next to your borewell and leave it into that re-charge well. The total cost for a recharge well will be about Rs. 35,000/-.

When you’re building your house minimum you’ll spend is about 10 lakh rupees so its very less as compared to the house, construction cost. But if you do all what’s needed your extra cost is actually just the filters and the filters can cost as less a 1500 Rs each. So about 3,000 rupees if you spend, you can store the water in your existing sump tank. Or if you spend 35,000 rupees you can then make a recharge well and put it into the aquifer. That’s what you need to do.

Arpita: What if I live in a rented house or a PG?

Vishwanath: In a PG it’s a bit more difficult because your accommodation is temporary. Typically PG people stay for 2-3 years, at best 4 years. Then they move on, that’s been the perception. It is a bit of a tough one to persuade the owners to be able to do RW harvesting. That’s a tough one. But the law backs you up. So, you can if necessary write to the Authority which is BWSSB saying your PG or your rented house does not have any RWH in which case the BWSSB will insist on the owner to make the RWH happen. That’s the way we can advocate for a good RWH.

The law says that that every new plot which is more than 30 feet by 40 feet has to have a RWH structure. And the RW structure has to store 20 liters per square meter of roof area, 10 liters per square meter of paved area and if it makes a recharge structure, it has to be a minimum of 3 meters deep. It’s for the authorities to insist on the owners of the building to make sure that they are legally compliant.

Arpita: What are some other ways to engage with our city and its water issues as citizens?

Vishwanath: The moment you switch on a bulb you’re impacting water use somewhere. Whatever you eat, on your food plate the wheat, the rice choice that you make, impacts water somewhere else down the line. The chemicals you use ends up in our drains and ends up polluting water just powders, just face wash, just even in a toothpaste. So the way we’ve architected ourselves as an economic society has tremendous impact on water that we now need to reverse some of these things, and to learn and to work effectively with nature to make sure that we restore our water bodies and that’s a huge challenge.

Go to the nearest lake in your neighborhood and become a member of the lake group. Every lake in Bangalore more or less has a lake group, which is working to save the lake and protect it. They usually meet on Sunday’s. Usually it’s about two hours of discussion and work. So join a lake group nearest to your house or wherever you’re residing. If there is no lake group, create one get onto the Facebook get on WhatsApp and you have friends of lakes. They’ll help you to take the process forward. It’s going to be a learning experience, but there will be great rewards in terms of just the societal engagement with water and the kind of learnings that come up with what is happening to a lake and what can be done to protect it.

Outro: Benjamin Franklin is reported to have once said: “When the well’s dry, we know the worth of water.” In many cities of India, we are reaching that point where the worth of water is increasingly becoming clear. Yet the consolation is that there’s something each of us can do to make it better. Whether you are building a house or renting one; live in an already constructed house or are rooming at a PG – all of us have a bit of leeway to change things around and become a little bit more efficient in our use of water. Your options go all the way from attaching simple water saving aerators to your taps to integrating RWH and water efficient systems into the very design of your house. I am already excited to begin with the water drum at home – do let us know how you think you can help the city do better with its precious water. We are always waiting to hear from you at www.thecuriocitycollective.org You can also know more about Vishwanath’s work at biometrust.org

In August we shift gears and enter the world of children. We explore what challenges and opportunities the lockdown and the pandemic have presented in the lives of children in Indian cities and discuss how we – as their community – can help and support them in these complicated times. Don’t forget to listen in!

This episode was made with the support of Srinidhi Raghavan and produced by The Bangalore Recording Company.