Rainwater harvesting rescues Bangalore residential community
Declining groundwater levels and increasing maintenance costs are the norm for most people these days, but residents of Rainbow Drive are exceptions.
18 Dec 2014
0 mins read
K.P. Singh shows one of the recharge wells

"Just having the people of Delhi look at their water meters everyday will enable the city to deal with its current water supply", said K.P Singh.

He should know.

Singh is a resident of Rainbow Drive, a bungalow community in Bangalore. Led by him, the society has revolutionised its water availability from chronic scarcity to self-sufficiency.

Borewells run dry

The society is spread on 36 acres of land with 400 plots. In 2007, when people were starting to build houses in the layout, water scarcity had already made itself felt. Out of 8 existing borewells ranging from 250 ft to 1000 ft deep, 6 had gone dry. With everyone following the usual solution to dig a borewell, they realised soon enough that this method was not only expensive but also a wasted effort as the water yield was becoming more and more unreliable since everyone was tapping into the same depleted aquifer. So the society decided to direct money towards groundwater recharge, water management measures, and recycling and resuing water. 

Rainbow Drive contacted Biome, a consulting company that designs and implements rainwater harvesting systems. They did a study of the entire layout including the borewell locations and land gradient, and calculated the water available for recharge. The simplest option was to recharge the groundwater and this can be done using a recharge well is a 25-30' deep pit lined with concrete rings and covered with a RCC slab. Water is directed into this well, from where it percolates into the surrounding soil and recharges the groundwater. Biome decided to locate the recharge pits along the storm water drains, as most of the runoff flows within these drains.

In addition to this, each house was also encouraged to store and use roof runoff and divert the overflow into a recharge well but it wasn't so simple to convince the community.

The Committee overcomes opposition

Initially Singh and Manjunath faced opposition from people who did not believe this would benefit them. Singh recalls that considerable and recurring interaction between society members and residents was required to get the message across and this continues even today. All meetings are open to all residents in addition to the weekly open houses to resolve concerns. The benefit of this is that it removes mistrust.

Society members not only present an option, but also research and present data and arguments. Also, the community recharge wells were constructed long before they made private wells mandatory and thus had already demonstrated the results when discussions were held.

Society members also made it easy for the community to begin rainwater harvesting. With their network of trusted workers and reliable estimates, they supervise the efforts themselves too. This also lowers resistance from those who are unconvinced. As Singh remarked, "Writing a cheque is the easiest thing, other things are really tough".

Solution: Recharging the groundwater

The society committee spoke to the residents about it, and made rainwater harvesting mandatory. Singh and Manjunath did all the groundwork to facilitate this, including speaking with various well-diggers, getting information and estimates.

When this process was put in place, the whole community came together to support it. They started off in 2007 by digging 10 recharge wells. This number stands at 330 in just 7 years!

For their effort, Rainbow Drive is now known to other communities in Bangalore. People regularly call them up and ask for advice. Thus the initial legwork done has facilitated rainwater harvesting in the entire area. However, the work does not end with sourcing the well-diggers. It needs regular monitoring too. The residents need to check if the well is being dug properly, if water is actually going into the ground, and more importantly, if it is impacting the water table.

Success in the first year

The very first year itself yielded tangible benefits in the form of raised water levels. The yield of the existing borewells stabilised and some defunct borewells also began to yield water. The recharge wells also managed to solve another problem that the community faced -- flooding! The layout is such that it slopes towards the main exit. During the monsoons, there would be a pool of water there to a depth of 5-6', effectively trapping people inside. As they started harvesting rainwater, more and more water started being held in the ground upstream and flooding was no longer an issue.

One unexpected result has been the formation of a posse of people who are well-experienced and knowledgeable about the construction of recharge wells. There is stiff competition amongst them, and this in turn has led to their being highly-motivated campaigners for rainwater harvesting among the neighbouring communities.

Reducing water consumption

Rainbow Drive realised that groundwater recharge alone would not solve their entire water problems since their requirement was much more than the rainfall yield. Therefore it was necessary to make sure that the demand for water was as low as possible. There are three ways of doing this:

  • Technical solutions such as low-flow faucets
  • Education and increasing awareness
  • Increasing water tariff

Rainbow Drive focused on the latter two methods.

They decided to ban individual borewells and only use community borewells. This also benefitted residents by removing the onus of maintenance from them. As Singh explained, "Sinking a borewell costs Rs. 2.5 lakhs, and every time you need to repair anything, the bill is a minimum of Rs. 10,000. Plus nearly an entire day is gone in following up on the repair".

Currently, the society relies on 5 community borewells, of which 3 supply the majority of water. Since they manage the water themselves including pumping it out to the overhead tank and distributing it, they have worked out a tariff. This is an increasing block tariff such that people who use a lot of water are penalised.

The tariff implemented is 0-15 kilo litres: 30 rs per KL, 15-25KL: 50 rs and 25 KL+: 150 rs

Before the slabs were created, people would routinely consume as high as 50kl per month. Now, 90% of the houses are below 25kl. No household is above 35kl, and only 10 households are above 30kl. Just looking at one's water meter can make them realise the amount that is wasted. People do not want the stigma of bearing punitive slabs, so they monitor themselves very closely. This has become a habit and some check the water meters daily.

Unchanged maintenance charges

An unlooked for benefit was the savings in operation and maintenance. In 2013, the society saved Rs.10 lakh in maintenance costs. Due to the reduced consumption, pumping hours are less. This also means less stress on electrical infrastructure and on the running of the motor. Thus, this year the society has not needed to increase its maintenance costs at all, which is a miracle given the inflation!

A water-secure community

Since 2007, by continuously working on groundwater recharge and groundwater management, measuring and metering of use, and wastewater treatment, the community now is able to get water at 250 feet. Other than occasional purchase of water for special events, they are managing with their own water.

They are, most justifiably, very proud of their story.

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