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Biome Environmental Trust
Water Management in IndiaThe role of Rainwater Harvesting
Water demand
Agriculture water demand will be the highest category of demandIndustrial water demand will be the fastest growing demand
Groundwater
India has the single largest exploitation of groundwater in the world with over 20 million bore-wells65 % of the net irrigated land gets water from bore-wells85 % of rural habitations depend on groundwater
PARADOX ?
Water in the city : Bangalore
Lakes and tanks : 261 in 1960
81 in 1997 55 in 2000
Lake development authority created to preserve and enhance surface water bodies in city
Bangalore need
Bangalore
Bangalore gets its water from the Cauvery 95 kms and 500 meters below the city
Water supply and sources in Bangalore
• Piped water supply :Current Demand : 1,500 Million Litres per Day Investment Rs.60,000 million ($ 1500 million)Supply : Around 900 MLDShortage covered by : Ground Water !!!
• Rainwater :3,000 Million Litres per Day (Area of 1200sqkm)Rs. “0.00”(zero) ?
Can a better balance be reached ??
Gated Layouts/Apartments/Homes
: Integrated Water Management
IMPORTANT REALITIESMulti-Sourcing of Water : tanker, piped, borewell, openwellDependence on ground water : borewells are drying up and getting deeperClean your own dirty water : What goes around comes around
IMPORTANT PRINCIPLESConservation : Dont use water wastefully Demand Management : Cycle and Recycle & harvestSecuring sources of water : measure, limit extraction and rechargeLeave the water out at the quality I extracted it
How much water do I use ?
Use Litres/person
Drinking 3
Cooking 4
Bathing 20
Flushing 40
Washing-clothes 25
Washing Utensils 20
Gardening 23
Total 135
Consumption range :
from 50 to 300 liters per person per day
Rainwater harvesting
components:
3) Catchment
4) Conveyance
5) Filtration
6) Storage
7) Recharge
<<< The saree is the
Catchment, conveyance
And filter !!!!!!
The collection and storage of rain for future productive use
MONTH DAYS QUANTITY (mm)
JAN 0.2 2.70
FEB 0.5 7.20
MAR 0.4 4.40
APR 3.0 46.30
MAY 7.0 119.60
JUN 6.4 80.80
JUL 8.3 110.20
AUG 10.0 137.00
SEP 9.3 194.80
OCT 9.0 180.40
NOV 4.0 64.50
DEC 1.7 22.10
TOTAL 59.8 970.00
Rainfall pattern in Bangalore
30 years data
Water harvesting and water reuse in a house
How much water can I harvest
Plot Size Area(sqm) Avg 30mm rain runoff (KL)
Annual 970mm rain runoff (KL)
No of days of use
30ft x 40ft 110 3 96 142
60ft x 40ft 220 6 192 285
50ft x 80ft 367 10 321 475• Assumed 5 member families with a daily per capita consumption of 135 litres
• Assumed only 90% runoff from rooftops
Rain barrel : easiest way to begin rainwater harvesting
First Rain separator and Filtration
Locate Recharge Wells / Other appropriate Recharge structures strategically
Drain and Catchment Management
Recharge wells details
Silt and leaves trap in a stormwater drainCovers : grilled or perforated RCC
The pit has reach the silt layer
Pit and concrete rings
Placing of the rings
The making of a recharge well
A good water harvesting system will revive the dynamic water table and keep the wells full
Direct Borewell Recharge
Should be absolutely sure of
Water quality, water directly
Entering into the aquifer
BWSSB Act
• 2400sqft and above (existing homes)• 1200sqft and above (new homes)• 20 litres of storage/recharge per sqm of
rooftop• 10 litres of recharge per sqm of non
rooftop• VALIDATION/INSPECTION process ?
RAIN WATER HARVESTING FOR HOUSEHOLDS : Quality, Bangalore
CATCHMENT MANAGEMENT
Good Quality Catchment = Good Quality water (HH Rooftops water usually can be used
for Drinking and cooking with boiling / UV
treatment )
Rainwater is distilled water. Picks up
2.Urban pollution
3.Catchment contamination during run-off
SYSTEM -DESIGN
First Rain separation
Filtering of Water (Trade-offs exist)
Jyoti Meadows Apts
• Size - 44 households
• Water demand - 33 KL/day
• Water sources - BWSSB supply, tankers and borewell.
• Motivation for RWH - Increase the size of their BWSSB connection.
• Potential for RWH
• Roof area - 700 sqm
• Rainfall endowment - 6.7 lakh litres / annum (20 days of total demand)
• RWH strategy - rooftop RWH with groundwater recharge and storage in new RWH sump.
• Cost - Rs. 1.55 lakhs
11,000 litre rainwater tank Catchment roof area of 700 sqm
Overflow to well
Recharge/Open Well – 3ft dia, 15 ft depth Well yielded at around 10ft.
Rainbow Drive
Rainbow Drive
Wells in Storm Water Drains Metering of borewells Metering of consumption in individual
homes Increasing Block tariff Discount on water bill for implementing
RWH Increased awareness about water Looking and treating and reusing sewage
A typical roof in Bangalore
• Sterile,• Uninteresting
and• Heat sinks
Roofs and Terraces are 60 % of Bangalore
Can they be smarter ?– Since they receive----------– maximum sunlight and heat– all the rain– lots of wind and– a whole bunch of birds, butterflies and bees
– Can they solve Bangalore’s water, wastewater, energy, sewage, food and bio-diversity problem ?
How about? A roof that grows rice
Grown using a 8 cm organic mulch on pond lining sheets
So what can a smart roof do?
• Provide– Food security… and grow rice, banana,
vegetables – Water security .. and treat waste water
– Energy security… and keep the house cool– Ecological security… and help save the
sparrow
Harvests rainHarvesting rainwater
Uses the Sun- solar energy for cooking, lighting and water heating
Using grey-water from the washing machine and bath water
Roof
• 100 sq. mt. 100,000 litres of water• 100 sq. mt 200 kgs of rice and vegetables• 100 sq. mt. All the grey water –100 ltrs/day• 100 sq.mt All the urine 1500 litres / year• 100 sq. mt All the solid waste generated• 100 sq mt 32 different species of birds• 100 SQ mt heat 100 litres daily• Light 12 bulbs• Cook for 4 people lunch and dinner
DEWATS
Project Ideas
Calculating the water demand (by end use) for the campus and working out the water balance
Mapping out the water table and water quality in a local area
Calculating RWH potential for a campus Designing and building an RWH system Designing and building a DEWATS
system
Biome Environmental Trust(Rainwater Club)
[email protected] www.rainwaterclub.org 1022, 1st floor, 6th Block,
HMT Layout, Vidyaranyapura, Bangalore – 560 097,
Phone : 080 41672790