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)

rainwaterclub@gmail.com www.rainwaterclub.org 1022, 1st floor, 6th Block,

HMT Layout, Vidyaranyapura, Bangalore – 560 097,

Phone : 080 41672790