Transcript Mumbai - Rainwater Harvesting

JALSWARAJMAKING WATER EVERYBODY’S BUSINESS
Centre for Science and Environment, New Delhi
Centre for Science and Environment, New Delhi
Once consisted of group
of seven islands called
Colaba, Mazagaon, Old
woman’s Island, Wadala,
Mahim, Parel and
Matunga – Sion.
Vehar lake
Tulsi Lake
Tansa Dam
Vaitarna
INCREASE IN POPULATION
14
12
12
IN M ILLIONS
10
8
6
4
3
2002
2
1951
0
1
2
DEMAND, SUPPLY AND GAP
IN M ILLION LITRES PER DAY
4000
3400
2900
3500
3000
2500
2000
1500
500
1000
500
0
1
2
SOURCE : MUNICIPAL CORPORATION OF BRIHANMUMBAI
3
PRESENT WATER SOURCE
68
18
455
1365
1044
WHO GETS HOW MUCH…
• BMC has extensive network…
BUT
Distribution is not uniform.
Suburban consumers have to supplement with
tankers—spending at least Rs 450 per day
Also quality of tanker water is a major
concern.
The amount that goes ‘unaccounted for’…
About 20 to 25 per cent is lost in leakage and
pilferage.
GROUNDWATER QUALITY…
SEA WATER INTRUSION – Colaba, Dharvi, Khar,
Anderi, Chembur, Malad etc.
INDUSTRIAL POLLUTION – Greater mumbai area
( High Nitrate, trace elements like Cu, Cr, Hg etc are
found in water)
Source: Central Ground Water Board
IN MILLION LITRES PER
DAY
FUTURE DEMAND, SUPPLY AND GAP
6000
5400
5000
3355
4000
2045
3000
2000
1000
0
1
2
MIDDLE VAITARNA STILL
SOURCE : BMC
WAITING FOR CLEARENCE
3
And WASTAGE…
FLUSHED down the drain
• Only 20 per cent of the water is used
for drinking, cooking;
• Over 60 per cent is used for bathing,
washing and flushing down the toilet.
Important that our water toilets are still
10-12 litres per each pull of the chain.
Literally, water down the drain…
...80% potable water ends up as wastewater
WE ALL LIVE DOWNSTREAM
• Only 24 per cent of the wastewater generated by urban
India is treated—Mumbai accounts for 23 per cent of
the total amount produced
• The rest 76 per cent is disposed of into WATER
BODIES (rivers, lakes etc) untreated
• These water bodies are the water sources for the
cities in the down stream
But, strangely the supply is almost FREE
• Water is cheapest in Delhi. 35 per KL as compared to
production cost of Rs 6-7 per Kl.
• Mumbai is in a better position, the cost for domestic supply is
Rs 2.25 per KL and the production cost is Rs 5.74 per KL
• In Indore the cost for domestic 2.00 per KL and the production
cost is Rs 9.50 KL.
• Bangalore charges Rs 5-60 per KL and the production cost is
Rs 13 per KL.
WATER HARVESTING POTENTIAL OF MUMBAI
Area
– 437 sq kmts
Annual avg .rainfall – 2000 mm
Potential
- 2394.52 MLD
Present water supply = 2900 MLD
Options:Storage;recycling; and recharge
Even if we assume 70 % of the area to be developed, 50 % of it
to be roofed and we collect 70 % of the water falling over it, the
quantity of rainwater that can be harvested works out to 589.34
MLD. This is a sizeable quantity compared to water supply to
Mumbai. It may also be reminded that the Middle Vaitarna
project is for 455 MLD.
SUCCESS STORIES IN MUMBAI…
BEST BUS DEPOT
TATA INSTITUTE
OF SOCIAL
SCIENCE
Basic concerns of a
Mumbaikar…
• Reclaimed land and threat of salinity. Quality of
water—of both municipal supply and tankers
• Unequal distribution
• Wasteful consumption pattern—leading to
overwithdrawal from sources—heading for urbanrural conflict?
Therefore, overall water management is the order of
the day—with RWH as a key component
Way AHEAD
• Create informed public opinion…the ALMs can
play a key role here
• Training the real users
• Strict legislation
Mumbai
• Mumbai Municipal Corporation has made
rainwater harvesting (RWH) mandatory to the
properties having plot area more than 1000 sq.
mts.
• This condition will also be made applicable to
existing buildings in near future.
• Recycling has been made compulsory for
buildings having centralised A C plants.
• BMC will supply 90 LPCD instead of 135 lpcd to
ensure RWH will supplement the gap.
Role of the people..
• None of this will work unless….
The citizens make rainwater harvesting their
own business