Rain Water Harvesting

Ease the pressure

Make the most of the upcoming monsoons by harvesting the rain water, says Shilpa Sachdev

Rains are the best source of fresh water. They are perennial and free falling. If conserved properly, the rain water is good enough to take care of a good percentage of our daily water supply needs. This not only means less dependence on external sources of water but is also a more sustainable option in the long run. More and more housing societies across the city have started adopting rain water harvesting and are reaping rich benefits.

The housing society at Kalpataru Gardens in Ashoknagar, Kandivali (E) set up a rain water harvesting unit three years back and have succeeded in saving up on their ground water reserves. Chairman of the society Vasant Patil says, “The absorption levels have lowered and the amount of run down water has gone up in the city. The water supplied by the municipal corporation is around 40-50% of the sanctioned quota of 90 litres per member of family of five i.e 450 litres per day per family. It is not possible to meet this requirement only by the water supplied by the municipal corporation. We have set up a ring well around the bore well that collects rain water from the terrace and the surface areas through storm water drains during the monsoons. It has helped increase the output of the bore wells. Earlier, the water levels would dry up by around January but now we continue to get sufficient water till May end, which is a good three-four months extension.”

Ghatkopar resident Gunvant Sheth also got a rain water harvesting system installed in his bungalow. He says it is important to make use of available resources. “You cannot only go on taking water from the ground. You also need to give back and replenish the resources. Rain water harvesting is an ideal way to do the same so that in the longer run you don’t have to face a crisis. The water charges by the municipal authorities are consistently going up. Using filtered water for non-potable purposes is a criminal wastage of resources. We have installed a rainwater harvesting system only last year but it will take at least two more years for the results to start pouring in. Some rebates from the government will encourage the people to take it up more seriously.”

Rain water harvesting is the best and the easiest tool to manage water resources according to Sandeep Adhyapak of Waterfield Technologies who have designed rain water harvesting projects for many housing societies. He says, “We installed the rain water harvesting system in our society Redwoods Co-operative Housing Society in Mulund in December 2007 at a cost of Rs 5.5 lakh. In the last five years, the water savings have been to the tune of Rs 40 lakhs when compared to the cost of the tankers that were consumed by the society. It is a one-time cost but the benefits accrue over the lifetime. It ensures that a society becomes self-sufficient and sustainable and also ensures equitable distribution of available water resources. The system aims at decentralising the water supply system. At least a part of the water requirement can be fulfilled by channelising the rain water collected from terraces and roofs. By recharging the ground water, one can also put a check on its salinity levels.”

He suggests that for those interested, they must take an opinion from an expert who understands the subject well and ensure the system is practical and cost effective. He also feels that there is a need for a clear cut framed policy from the municipal corporation that lists down the criteria for consultants and also offers subsidies for such projects. “The Brihanmumbai Municipal Corporation has made it mandatory for all new buildings to have rain water harvesting system but nothing has been done about the old buildings. In places like Chennai there is Rs 1500 rebate given on a rain water harvesting project and in Indore it is 6%. We need similar incentives to encourage the movement in Mumbai. The Thane Municipal Corporation has already installed such systems in the fire brigade building and their ward office in Kopri. Seeing is believing. The municipal authorities should showcase rain water harvesting projects by installing them in their own projects and create case studies so that people can visit and see how the process actually works. Then they will be more comfortable and open to the idea.”

Giving their view, a senior office from the Municipal Corporation of Greater Mumbai (MCGM) says, “The corporation is supplying good water to the citizens at Rs 3.50 per kilo litre. When you get something so cheap the importance is not felt. Compare 1000 litres with 1000 bottles of mineral water and the amount you pay for it will run into thousands of rupees. People waste a lot of water without giving it a thought because they are not used to scarcity in the real sense. Having wells and bore wells is an alternative but Mumbai being a coastal city, the more water you draw from the ground, there are more chances of sea water ingression. That is why it is important to harvest rain water and use it in time when it is available. Harvesting roof top rain water will reduce pressure on water resources and help in creating ground water reserves, which will in turn curb sea water ingression. We have made it mandatory for new buildings but for old buildings we already have had an agreement which can’t be changed unilaterally. It is a voluntary exercise and hence moving at a slow pace. The proposals for a price hike in water charges as well as providing subsidies are under consideration. The need of the hour is to create more awareness and sensitise people.”

The MCGM has taken up a few initiatives for the same. The officer adds, “We have a technical cell for rain water harvesting where we give guidance to societies free of cost if they want to set up a RWH unit. We have already attended to more than 400 societies on the same. What we need is a letter of intent from society's letterhead, layout plan, bore well/well details and water bill. Over the last six year, we have also started a ‘jal mela’ which is an open forum where people can discuss water issues. We need to create a culture of conserving water so we are targeting children as a long term plan. We are releasing a set of school books for all standards to build the value system. Mumbai is huge and people of different cultures reside here so they can’t be approached in one single pattern. But efforts are on."