SAVE THE RAINWATER REVOLUTION

Rainwater harvesting is our only hope in the face of impending water scarcity. A few experts offer solutions on recharging wells and installing rainwater harvesting units at home. Read on…

It’s magical when it rains after a hot summer and the earth laps it up. Nature has its way of recharging the groundwater table every monsoon. But, do we allow it free rein?

By concreting roads, pavements and open spaces, we are doing gross injustice to this natural process causing most of this precious resource to drain into the sewers. There’s abundant scope to harness the rain, recharge wells, store rainwater and use it for drinking and our daily needs. All it takes is an action plan for Rainwater Harvesting (RWH) on a war footing.

REINING IN THE RAIN

PREP BEFORE CONSTRUCTION:

If you pre-plan the RWH system before constructing your house, you can aesthetically design/camouflage/ showcase the RWH elements. The RWH unit usually requires a number of pipes, which act as collectors and direct the collected water to the harvest zone. The route needs filters, which improve the quality of water collected. Today, people are aware of the advantages of RWH systems and look forward to installing them. This, fuelled by mandatory norms by the government, has created good demand; hence, professional companies have invested into this area and are offering it as a complete solution.

MINIMAL COST:

You can lead the collected water into a harvest pit or around a borewell. It depends on the collection area, which essentially is the roof. The run off from the surrounding surface area can also be led into the same harvest pit. So, you can begin with one RWH pit, which is about two feet in diameter and 10 feet deep, filled with gravel, sand and material, which will help absorb and retain water, and then percolate down slowly into the earth. The cost of a RWH system for a medium sized house is Rs 22,000 to 25,000.

RECHARGE, RESTORE

SWIFT SOLUTIONS:

There are two ways that the authorities can work towards recharging the groundwater.

1 Clean and desilt lakes. A freshly desilted lake can recharge upto 20 litres per sq m per day. A lake like Bengaluru’s Jakkur with a 50-hectare water spread can actually recharge 10 million litres of water per day;

2 Make recharge wells and incentivise them at the household level. Recharge wells are typically three feet in diameter and 20 ft deep, lined with precast concrete rings and can pick both, rooftop rainwater and water from clean storm drains and send it to the aquifer at sometimes 10,000 litres an hour.

RWH TECHNIQUES:

Rain barrel: Connect rooftop drain pipes to a HDPE tank. Thereafter, tie a piece of cloth at the end of the pipe as a filter.

Sump tank: Rainwater filters are available in the market. Connect them to the rainwater downpipes and lead them into an existing/newly built sump tank.

Recharge wells/existing wells: Connect rooftop rainwater pipes to an existing well or a new recharge well (typically three feet in diameter and 20 feet deep).

Recharge borewells: If you have a defunct borewell, connect rooftop rainwater pipes through a filter to the defunct borewell casing and recharging the aquifer.