More than half of the 55 residential societies here have installed rainwater harvesting structures in the last six months to recharge the groundwater table. The installations are simple, practical, inexpensive and required only ten days of work, residents said.
The societies deployed different strategies from channelizing the rainwater coming down nearby hills into recharge pits to recharging borewells with rooftop rainwater and even using the downward slope of the area to direct potential surface rainwater deep into the ground.
Stormwater lines within their premises were also diverted into borewell pits. The idea, a resident said, is to capture any and all forms of water and redirect it approximately 100ft below the surface, beyond even the hard basalt rock into the layer of soft and water absorbing rocks that have the capacity of storing million litres of water.
The residents say that the severe drought in the state, recurring reports of the depleting groundwater table in the city and the mounting bills for water tankers became catalysts for their action. for many societies in the area They add that the societies were awakened to the benefits for groundwater augmentation by water conservation experts who not only addressed seminars and lectures for the residents, but also visited the societies to understand their specific needs. The experts found that very few recharge borewell structures were available in the area.
Kumar Peninsula a cooperative housing society of 62 families has implemented a recharge system which uses surface rainwater as well as water flowing from the 300m-high hills behind it. The best part - the society managed the entire work without a consultant, including procurement of material, labour and arranging for a borewell contractor.
As part of the system, three recharge structures were built in different locations to channelize the water into the ground. The recharge pits are simple structures while the first layer on the ground is pieces of bricks, the second layer is made of gravel, the third layer is khadi (to act as a filter) and the topmost layer is sand. Each layer is approximately 1.5ft high and the pit's depth is 6ft. The top layer of the filter media should have a simple mosquito net-like material covering it, which should be cleaned within the first week of regular rains to prevent accumulation of silt, a resident said.
Satisfied with the job, done, ahead of the monsoon, the society's chairman Gulab Patil said, "It took us just over a week to finish the project. Thanks to the increase in awareness on the need to recharge groundwater, convincing the residents was hardly a challenge. We managed to keep the cost low. With our system in place, we will manage to recharge the groundwater table with thousands of litres of water. We don't know who is going to benefit or where the water would flow. We have done it not for the benefit of our society, but because recharging groundwater is our duty."
The system was replicated in Deepa Society, while Padmavilas Society, which is a few metres away, has built holes into its boundary wall bordering the hills to collect rainwater spill into its borewell.
Vikram Kotnis, of Deepa Society, said, "This kind of system is going to save the society thousands of rupees that is being currently spent on buying water tankers. Faster the people adopt it, the better it would be for everyone."
Converting a potential adversity into an advantage,
Whispering Wind I Society, has implemented four mini systems. Not only has it channelized huge volumes of surface water in the society (which is constructed on sloping land) into three recharge pits, but it has also tried to use the technique to recharge a traditional well in its premises. Committee member Sushil Jawale said, "We spend nearly Rs 1 lakh every month on tankers. Incurring this one-time cost is more sensible.. If everyone in the area does it, everyone would benefit."
Already tanker-free for a long time, Kubera Bahar Society has implemented the second phase of its rainwater harvesting project by recharging another borewell on its premises with terrace rainwater, while Kumar Sahwas is using surface rainwater from roads to recharge their borewell. Other societies like Kumar Shantinekatan, Ojas, Felicita, Mont Vert Belrose, Mont Vert Biaritz II, Meera, Blossom & Springs, Rolling Hills and Buena Vista are channelizing terrace and podium rainwater runoff.
Committee members of Baner Pashan Link Road Vikas Samiti, who have been visiting societies in the area to convince them of the importance of groundwater recharge, are confident of getting all member societies on board. "We are urging residents to take up the initiative. Many are initially sceptical, but once we demonstrate the benefits and the ease of implementation, people come on board. Everyone is concerned about water problems and this is the simplest way to do our bit," a member said.