Chennai

A story for a rainy day

Two residents of Sabari Terrace on Old Mahabalipuram Road relate how their gated community harvested 10 lakh litres of rainwater this monsoon

It’s not about the 10,00,000 litres of rainwater harvested... It’s not about the 10,000 people who “liked” this on social media... it’s not even about the 1,000 people who shared the success story… and it’s not about the 100 people who called to say “wow”... but it’s about the 10 people who got inspired to implement the same idea in their homes. This makes a good rainy day story.

For all buildings completed in the last 15-odd years, it was mandatory to have rainwater recharge pits. But, in many, they have been reduced to vestigial organs today.

At Sabari Terrace, some eight years ago, we got all the recharge pits cleaned. This step we took in harvesting rainwater has been recharging the groundwater table. But we felt more needed to do done.

They say that when you can’t see the answer to a problem, you have to take a step back to look at the ‘bigger picture’. That is exactly what we did. We looked at our apartment complex from a bird’s eye view and drew our inspiration from that.

Traditionally, we used our terraces in summer to make vadams and appalams or may be just to dry the clothes… and in winter, to take a walk and enjoy the cool weather. But today, all is forgotten in the ‘vertical villages’ that we live in. Life in a multi-storeyed complex is very different from that in a traditional home.

This thought was one of the driving factors that inspired us to look at rainwater harvesting from terraces.

With some advice from the man behind The Rain Centre, Sekar Raghavan, we decided that the best way to use the blessings that the rain gods were showering upon us was to divert them into our existing underground sumps.

The next step was to put together an action plan and execute it. It took some effort to convince members of our community to agree because we could not find a working example in our neighbourhood. This had not been done before. So along with our technical support staff — Sampath and Murugan — who were immediately excited, we drew up a plan. Our manager Prakash helped us estimate the costs.

Our association president Srinivas felt that we should try it out in one block and see how it works. So in November last year, we commissioned the rainwater harvesting from our terrace in the first block. A couple of days later when the committee saw the pure rainwater that was collected, our treasurer Binoy gave the green signal. It took us some time to set aside funds for this and slowly the project took off.

1500 ft of 4” pipe, 75 L-bends, 60 T-bends, 40 Control valves and 2 Sintex tanks of 3KL later, we were able to complete the linking of all our terrace water drains just in time for the arrival of the north-east monsoon this year.

The rest, as they say, is history. Our housekeeping supervisor Padmapriya and her team ensure that the terrace is cleaned every few days — especially on days that rain is predicted. This ensures that no leaves, sand or dirt clogs up the pipes. With approximately 18,000 sq. ft. of terrace, we get 20,000 litres of water for every hour of moderate rain.

The total money spent on the installation till date is about ₹2,50,000 and the total payback (in terms of water tanker cost savings) till date is about ₹60,000. Since our project was implemented in many stages, more than half our water collection has happened in the rainy days of October and November of 2018. Extrapolating the numbers, we predict that if it rains for 40-50 days in a year… we can harvest the fresh water requirement for 70-90 days. If we look at it in pure economic terms, we are likely to recover the money invested in less than 3 years. So even if you are not ecologically-inclined, it makes pure economic sense to invest in this type of rainwater harvesting.

Even since we showcased the success of this rainwater harvesting method, highlighting the economic benefits, many residents welfare associations, especially on OMR, have visited us to study and understand the process. Some have even begun to implement it in stages. We hope that soon, millions of square-feet of terraces on OMR will be harvesting pure clear water! They say the first million is always the hardest…. Well, we have reached that milestone. (Harsha Koda and Prabha Koda are also active members of the Federation of OMR Residents Associations.)

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Printable version | Apr 4, 2020 9:38:25 AM | https://www.thehindu.com/news/cities/chennai/a-story-for-a-rainy-day/article25741208.ece

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