Water and youWhat you do makes up the

bigger picture

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

Real Consumption range :

from 50 to 300 liters per person per day

National Town planning Norms :

Urban : 135 Lpcd

Rural (Karnataka) : 55 Lpcd

How much

Water do

YOU

Use ?

Local hydrologic cycle

What about the rain ? : Local hydrologic cycle

Site : 30 * 40 (Area 110 sqm)Annual rainfall on it in B’lore : 106700 Litres

Before construction After construction

Runoff : 10%10670 Litres / annum

Runoff: 80%85360 Litres / annum

Difference :74690 Litres / annum

Who should manage this excess ?

Let’s look at the numbers more closely…..Rainfall Water falling on the roof

(30 * 40 site)

10 mm (small shower) 1000 litres

30 mm (Average shower) 3000 litres

60mm (heavy shower) 6000 litres

Annually in Bangalore – 970mm 87300 litres

4 member household, @ 135 lpcd needs 540 litres / dayi.e. in Bangalore there is enough rain falling for 161 days of a family

OrFor nearly 5.5 months of the year

that is

Almost 50% of a household’s needs !!!Can we capture this store it or recharge it into our borewells

(or can we do rainwater harvesting) ?

Most important principles of RWH – 2:Rainfall pattern & Geology

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

Bangalore:

Rainfall more evenly spread better forDirect storage and Use.

Geology and aquifer regime to be suitable for recharge. Recharge to be designed for local conditions.

Thumb rule : Open wells good in deccan plateau. Depth of well necessary different in different place. 20ft minimum thumb rule.

Tank Size Study

0

50

100

150

200

250

300

5000 10000 15000 20000 25000 30000 35000 40000 45000

Tank sizes

Day

s se

rvic

ed

Household Rainwater Harvesting:

Plot size

Area in Sft

Area In SqM

Runoff for a 30mm rain (Liters)

Runoff for a 60mm rain (Liters)

Annual Runoff (Liters)

30x40 1200 111.52 3,011.15

6,022.30

97,360.59

40x60 2400 223.04 6,022.30

12,044.61

194,721.19

RAIN WATER HARVESTING FOR HOUSEHOLDS : Quantity, Bangalore

Most important principles of RWH – 1:Catchment and type of harvesting

Direct Storage& Use

CLEAN CATCHMENTSSTORAGE : SUMPS, RAIN BARRELS (etc)

NOT-SO CLEAN CATCHMENTS

Recharge

RECHARGE : OPEN WELL, DIRECT BOREWELL RECHARGE, (etc)

….So how clean is Rainwater ?....

Rainwater in a GlassCauvery water in a Glass

-Guess

Which is which ?

A Bucket of Rainwater in Kurubarakunte village, Bangalore

….Really as clean as your roof (catchment) is…

Clean Rainwater comes fromCatchments that are clean – Roof tops are the cleanest Catchment.

Keep your roof clean :No junking, no pets, no crackers, no holi, No chemical pesticides/fertilisers on the roof

Managing Rainwater Quality : rainwater picks up contaminants from :1. Urban pollution – First Rain separation2. Contamination from the catchment – Catchment management, Pre-filtering 3. Rainwater has low TDS, low Hardness and low all other counts !!!

Rainwater, for drinking will need Point of Use treatment for Bacterial contamination

Eg: SODIS, Good rolling boil, Aquaguard etc.

Site Selection for Infiltration

Many factors affect the suitability of a site as an infiltration facility for the disposal of stormwater. Among these, the following are most important:• Depth to groundwater• Surface soil type• Underlying soil type• Vegetation cover of the infiltrating surface• The uses of the infiltrating surfaces• The ratio of tributary impervious surface to the infiltrating surface

http://www.youtube.com/watch?v=6lVTPhsvp38&feature=channel_page

Recharge pit around bore wells

The pit has reach the silt layer

Pit and concrete rings

Placing of the rings

The making of a recharge well

Recharge wells details

Silt and leaves trap in a stormwater drainCovers : grilled or perforated RCC

Rainwater sent for recharge

Recharging a bore wellOutlet pipe in recharge well

Don’t forget the maintenance

Building bye-laws in Bangalore

• ALL buildings with roof area more than 100 square metres

• 20 litres for every sq. mt. (storage or recharge)• 60 litres for every square metre for more than

5000 square metre plot size

Demand – the heart of the scarcity problemWhat else can you do?

Reuse Waste Water (eg: Grey for flushing, Treated black/grey for irrigation)

And use the treated waste water to irrigateYour roof farm that produces food

Water harvesting and grey water reuse in a house

Turn sewage to a nutrient through Eco-san