“Does Mumbai feel the need to conserve water?” asked Sanjay Ubale, executive board member of Mumbai First at a conclave about water in Mumbai. With easy availability of water from seven reservoirs, the city has the best per capita water ratio in India, and so, there is less incentive to conserve water or practise rainwater harvesting, he explained.
Why would societies spend funds to store water for future use when they are getting water at highly subsidised rates round the year, he asked. Statistics too suggest the same.
Approximately only 3000 societies of the total estimated 20,000 societies in Mumbai had rainwater harvesting (RWH) between 2007 and 2021, as per a report by The Indian Express.
This is over and above the RWH initiatives undertaken by the Brihanmumbai Municipal Corporation (BMC) in its gardens. The BMC has dug about 1500 percolation pits in about 300 gardens and was in the process of constructing 700 more pits. That means about 30% of its 1068 gardens spread across the city have systems to recharge groundwater levels when it rains.
In part 1, Citizen Matters explored various types of rainwater harvesting systems and the ways to install them in independent houses or apartment complexes. In this part, we look at why Mumbai lags behind in having rainwater harvesting despite getting abundant rains.
Rainwater harvesting: Mandatory but not maintained
Though the BMC has made rainwater harvesting mandatory for new buildings since 2002, the implementation is a different story altogether.
As per procedures, new constructions are expected to hire a rainwater harvesting consultant to oversee and certify that a particular building has set up a RWH unit. Based on that certification, the BMC issues the Occupation Certificate (OC).
While builders build the rainwater harvesting system and hand it over to citizens for the sake of OC, many say that most societies neglect it, once OC is received.
“You cannot use the space of RWH since it is meant to be kept open for rainwater to collect. But, new buildings wait till the OC comes and then fill and close down the tank,” reveals a committee member of a new society, adding that people often view it as a waste.
Read more: Bengaluru, second highest in rainwater harvesting in Indian cities
Residents reluctant to harvest rainwater
The two main purposes of rainwater harvesting – to save rainwater for future use and to recharge groundwater, hardly receive any support from residents.
Dhaval Shah, co-founder of the Lokhandwala Citizens Association says, “The RWH apparatus requires annual maintenance and cleaning for its tanks and the pipelines. It needs funds, which residents perceive as a waste of money. It is also viewed as a waste of space and car parking is considered more important than this. The storage is impractical since it would hardly suffice for two days of flushing.”
Dr Subhajit Mukherjee, ambassador of the Maharashtra government’s Majhi Vasundhara Abhiyaan says that citizens have got careless about water, “People have money and they are willing to spend on water rather than look for solutions. Rainwater harvesting pits are often ignored and neglected by societies. I have even come across a RWH pit, which was used as a garbage dump because of lack of knowledge. People need to be taught the value of water.”
No incentive to do rainwater harvesting
Dhaval recalls that the BMC promised incentives like property tax rebate for old societies that install rainwater harvesting. While this prompted societies to undertake RWH and complete paperwork, the whole momentum fizzled out after they found that the rebate never reflected in their society bills.
Dr Subhajit laments poor citizen participation. “It gets implemented well only in government facilities but citizens seem least bothered. People don’t feel the need for rainwater harvesting even during water shortage. They find it more convenient to get a water tanker, which is just a phone call away, rather than conserve rainwater or even recharge groundwater,” he says. “When water is so easily available, they have no incentive to get into storing rainwater or even groundwater recharge.”
Preference for recharging over storage
Shrikant Govil, treasurer of Spring Leaf CHS, Kandivali which has about 84 flats, says that their society undertook rainwater harvesting around 8-9 years ago. This was done to recharge their borewell and not so much for storage of water.
Digging a borewell used to cost around Rs 2-3 lakhs then, setting up our RWH cost us about Rs 4-5 lakhs. They had to spend on installing rainwater harvesting system because their society was 22 years old, when builders did not provide it.
“It doesn’t store water. It just recharges our borewell. Earlier, the borewells would go dry in the summer months, but now they have water round the year.” The borewell water is crucial for them since they use it for their non-potable purposes like flushing and gardening.
Citizen apathy or feasibility issues?
Activists like Stalin Dayanand, director of NGO Vanashakti, which also works in the field of water conservation, feels that rainwater harvesting in its current format is not feasible. “How much water can you store and for how many days can it be utilised? How does it help to build tanks that can store water that can be useful only for a few days?” asks Stalin.
He also pointed that the storage tank at Hindmata with a 2 crore litre capacity does not prevent flooding there. Rainwater harvesting is expected to help in reducing water logging and flooding.
He says, “ Most of the rainwater harvesting regulations are random recommendations suggested by some consultant. They get implemented across the board without anyone bothering to check if these solutions are applicable for all over Mumbai.”
One size does not fit all in rainwater harvesting
Geologist Dr Amar Joshi feels that groundwater recharge cannot be done uniformly across the city. “A geological consultant should evaluate and determine the methodology of rainwater harvesting,” he says adding that factors like runoff coefficient, requirement of groundwater recharge and storage possibilities need to be considered.
He says, “There cannot be a one-size-fits all policy across the city because the soil type is the main factor for infiltration pits. It is different at different places. For example, recharge by pits may not even be possible at places where the water table is high. Hence, different locations need different solutions.”
Citizen activist Zoru Bhathena too is critical of the water resources management of the BMC and will be challenging the same in the courts.
“Isn’t it more practical to use the groundwater which has vast capacity to store water rather than focusing on conserving water in tanks for just a few days? Shouldn’t there be more emphasis on groundwater recharge rather than on storing rainwater? The real challenge is the falling water levels underground due to run-off water channeled into the sea through cemented drains rather than let them be absorbed by the ground,” says Zoru.
He also observed that large-scale digging for building basements, also affect groundwater levels. “There are over 10,000 buildings under construction in Mumbai with basements. To build these basements, a huge pit is dug, its soil and rocks excavated and groundwater drained off before being concretised. This is a huge waste of precious groundwater that could be better utilised.”
BMC’s rainwater harvesting efforts
The BMC does have a rainwater harvesting and water conservation cell, under the Hydraulic Engineering department, but it is more involved with the process of creating awareness about water conservation.
“While new buildings have their own rainwater harvesting, old buildings need to take permission from us to set it up. But very few societies approach us for it,” said an official associated with it.
| Call to action for better rainwater harvesting |
| Much needs to be done to get housing societies to take up and maintain RWH. Here are the steps that could be undertaken to get things back on track. * Societies need to be given incentives to do rainwater harvesting. * The promised property tax rebate scheme could be revived and highlighted as an incentive. * BMC must ensure continuous monitoring to check if buildings maintain RWH and keep it functional. * It must develop a mechanism to conduct regular checks of RWH facilities for bacterial contamination. * The RWH cell needs to be given more teeth to monitor implementation of RWH by societies rather than merely involve in awareness building exercises. * The city could also do with a consumption map of the city with a detailed door-to-door survey. The ORF recommends that such exercises must be carried out every 10 years. |