HT : Let's look for some fluid solutions : Sept 14, 2007

Let's look for some fluid solutions
 Mumbai has both a flooding problem during the monsoons and periodic water
cuts. The solution should be obvious: water harvesting, as Chennai is doing
with great results The key benefit for Mumbaikars from rainwater harvesting
will be in reducing their dependence on the ubiquitous water tanker
 VIJAY KRISHNA


R AINWATER HARVESTING is one of the keys to making Mumbai a more livable
city.

As Mumbai continues to grow, bringing water to the city from outside becomes
increasingly difficult. We are running out of sources to tap into. As
competition for this limited resource intensifies, people outside Mumbai are
not going to willingly give up their water for us. Rainwater harvesting is a
solution that is literally in our backyard.

How much water can Mumbai harvest? On long-term average, Mumbai gets about
2400 mm of rainfall a year. Taking an area of 437 sq km gives us about 2800
MLD (Million Litres per Day) over the course of a year. So depending on how
serious we are about it, we can get anywhere from zero to 2800 MLD of our
water requirements from rainwater harvesting. Compare this with Mumbai's
current water supply through BMC of about 3500 MLD, of which a fifth or more
is lost in leakages, and another 1000 MLD shortfall, which is met from other
sources. This should show us that rainwater harvesting has serious
potential.

The key benefit for Mumbaikars from rainwater harvesting will be in reducing
their dependence on the ubiquitous water tanker. With rainwater harvesting
in the rainy season, people should be able to meet their requirements along
with the BMC supply In fact several 'ear . ly adopters' of rainwater
harvesting report that the recharging is continuing to give them water even
in summer months. From the macro-view, more water from rainwater harvesting
means less water needs to come into the city from outside, reduc ing costs,
energy consumption, and increasing sustainability and dependability. As more
and more people harvest rain, there is going to be a perceptibly positive
effect on flooding - something surely no one will complain about.
We must recognise the limitations of the city administration in water supply
Despite the talk . of a world-class city and provid ing 24-by-7 water, BMC
cannot conjure water out of nowhere. As the city's needs grow, it becomes
ever harder to find new water sources and transport the water to the city As
a part of the . solution, BMC should aggressively promote rainwater
harvesting and legislate it after appropriate preparation. Businesses must
recognise that rainwater harvesting is a sound investment for ensuring
Mumbai's future. It must be implemented in offices as a matter of course.
Housing societies must be helped in implementing it. Asian Paints has set a
great example of rainwater harvesting and sound water management - and it
has added to its bottomline.

How are other cities faring? In October 2002, the government of Tamil Nadu
passed an ordinance making rainwater harvesting compulsory for all
residences and giving people a year to construct the facilities. This was
after the situation got extremely bad - in 2002, Chennai was getting a
jaw-dropping low supply of 194 MLD from the municipal corporation compared
to the requirement of 790 MLD. 2004 was a bad monsoon year and 2005 and 2006
were good years. Nowadays, Chennai is seeing rising groundwater levels. For
example, a study by Chennai Metrowater showed that between June 2005 and
2006, the average groundwater level in the city was up by 2.5 meters, thanks
to water harvesting. The trend of falling groundwater levels has been
reversed. Chennai now is better prepared to face a drought year. According
to Sekhar Raghavan of the Chennai Rain Center, saline water intrusion, a big
problem in coastal areas of the city has come down dramatically, with the
level of dissolved salts falling by as much as 80 per cent in some areas-
one of the big success stories of compulsory rainwater harvesting. This is
something Mumbai also stands to gain from harvesting rainwater. Chennai is
also experimenting with largescale desalination, but the cost of water
produced by that technology is very high.

Bangalore continues to grow rapidly but it has few water supply choices
left. There is only so much water it can extract from the Cauvery and the
interstate fight with Tamil Nadu over those waters make that hardly a
reliable source. Thus Bangalore too needs to adopt rainwater harvesting and
water recycling in a big way or suffer Chennai's painful experience.
There is every reason to make rainwater harvesting compulsory in most
cities, including Mumbai. The water crisis is real, and rainwater harvesting
is an essential component of the solution. So many housing societies and
companies have already implemented rainwater harvesting successfully There
is . no dearth of organisations in Mumbai that will offer support in
implementing it. Asian Paints runs a Total Water Management Center at its
Bhandup office that is free and open to everyone. The company says it has
helped people harvest 100 million litres of rainwater to date. Eureka Forbes
also offers free rainwater consultancy and has helped many housing societies
in setting up their rainwater harvesting systems. L&T Powai, Tata Institute
of Social Sciences, St.Catherine's Home, Andheri to name a few are
successfully using harvested rainwater. A listing of groups that offer
consultancy and design can be found at http://tinyurl.com/2lca98, along with
examples of successful rainwater harvesting. With the kind of rainfall
Mumbai gets, it is only commonsense that we use the water judiciously and
don't seesaw between floods and shortages.

There are some other aspects of the water problem that need to be looked
into. One is wastewater recycling, which has enormous potential. There are
already working examples that show its viability The other is water con .
servation - the best way to implement that is through pricing water at a
level that encourages people to conserve. But the pricing should be by
slabs, ensuring supply to everyone irrespective of their ability to pay .
Vijay Krishna works for Arghyam, a trust dedicated to water issues


Publication : HT; Section : Oped; Pg : 13; Date : 14/9/07
URL :
http://epaper.hindustantimes.com/artMailDisp.aspx?article=14_09_2007_013_001&typ=0&pub=264