For my final site visit, I went to see another rainwater harvesting system, this time in a house in Electronic City. The owner, Mr Swayambhu, had installed it in 2008 with the help of Biome, and since then it had been acting as a secondary water source for the family. I was curious to see – how well was it working now, after nearly a decade of usage? Like at Ambalipura, I began by taking a look at the infrastructure, then went through some basic questions with the owner.
Mr Swayambhu gave me a quick tour of the system, starting with the terrace and balcony. Rainwater would collect here, before flowing down through pipes to the ground floor to a T valve. This was meant to separate the first flush after each major rain, so as to ensure that the water that made it to the next stage was clean. From here it would pass through a basic filter of charcoal and stones. Then it would empty into a large sump built under the parking space of the house. Any excess water would be directed to a recharge well dug right next to the owner’s old borewell. The system was simple and elegant, if a little worn out by age.
To me it seemed decently maintained, considering the time that had passed since its installation. The catchment areas looked fairly well swept, and I could even make out that they had been given waterproof coatings in the past (although these were peeling off at the moment). Some parts of the piping were slightly broken; luckily there were no large leaks to be seen.
The first flush was seldom removed from the T valve, according to Mr Swayambhu, but in any case, whatever dust made it into the pipes was probably removed by the filter. At the end of the day, what came out of the taps was soft water that could be used for all purposes including drinking.
The main water source for the family was the city corporation, which sent them water tankers on a scheduled basis. Earlier, they had been using a four hundred feet -deep borewell, but they hadn’t checked it for water since it dried up a few years back. Rainwater was used as a backup, a secondary source, and fortunately it had all been going well, in spite of Bengaluru’s notoriously irregular rainfall patterns. As things were, Mr Swayambhu felt sure that they could have managed with rains as their only water source, if only he had designed the system to be on a larger scale: such was the amount of water that overflowed from the sump at times.
In terms of investment, it was not too expensive to set up the infrastructure, but this was probably because they were integrated into the house design. Mr Swayambhu suggested that perhaps he would have needed to spend more if he hadn’t thought of harvesting rainwater before building his house. The only noteworthy cost was that of the filter, which was added once the piping was complete. From a purely technical point of view, I strongly feel that seetting up and maintaining a similar RWH system should not be difficult for anyone in the city – provided they are willing to put some faith in their investment.
Of course, finding this inspiration is not always easy. No doubt many other people in Bengaluru are aware of rainwater harvesting and know its benefits, but for their own reasons they haven’t been able to turn thought to action. Perhaps they think it is impractical, or perhaps they prefer less time- consuming solutions. Whatever the case, the fact remains that the city’s water crisis is getting worse every year, and unless there is a shift to more sustainable water management practices, there could easily be a devastating water shortage in the near future.