Water

Rainwater harvestingRebuilding an urban

water cultureShubha Ramachandran

Biome Environmental Trust

The liberator – the hole in the ground which yielded precious

water

Did the Buddha drink from this well ? Sarnath 500 BCE

Vijayanagar Kingdom – 500 years ago

Bangalore – living history (100 years

old)

BANNERGHATTA ROAD

Photo : Norma Angelica Hernandez Bernal

Ultimate source of all water :

RAIN

Local hydrologic cycle

Twin problemsUrban FloodingWater Scarcity

PARADOX ?

Rainwater harvesting

components:

1) Catchment

2) Conveyance

3) Filtration

4) Storage

5) Recharge

<<< The saree is the

Catchment, conveyance

And filter !!!!!!

The collection and storage of rain for future productive use

Rainfall pattern in Tirupur

MONTH QUANTITY (mm)

JAN 14

FEB 6

MAR 13

APR 57

MAY 82

JUN 20

JUL 27

AUG 43

SEP 62

OCT 163

NOV 115

DEC 40

TOTAL 642

How much water can I harvest

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 : 55 Lpcd

RWH Potential (for every 100sqm of surface)

Nature of Surface

Runoff Coefficient

Runoff for average 30mm rain (in KL)

Annual runoff for 642mm (in KL)

Rooftop 0.8 2.4 51

Paved Area / Roads

0.5 1.5 32

Unpaved Areas / Garden

0.1 0.3 6

Case: Industry: RWH Potential as a % of Annual Demand

● Daily Demand = 15 KL (500 people x 30 lpcd)

● Annual Demand = 5475 KL (15 x 365)

● Total Campus = 3000sqm (~ 30,000sqft)

● Rooftops = 1500 sqm (50% of total area)

● RWH potential from rooftop = 733 KL (1500* 0.8 * 0.611 )

● Other Paved + Unpaved Areas = 1500 sqm

● RWH potential from non rooftops = 275 KL (1500×0.3×0.611)

● RWH Potential as a % of Annual Demand = 18% (733+275)/5475

….So how clean is Rainwater ?....

Rainwater in a Glass

-Guess

Which is which ?

A Bucket of Rainwater

A clean roof means clean water

Downpipes

Down water pipes made of - HDPE- PVC - Chains

Join all the pipes……

Gutters

Gutter-for sloping roof transmitted through- PVC- Polycarbonate- GI

- Aluminium- Stainless steel

PVC GUTTER

Clean Rainwater :FRS & Filtration

First rain separation – let the rain clean the roof

Details of a rain barrel

Aluminium basket filter

Plastic basket filter

Filter

Commercial Filters

Rain barrel : easiest way to begin rainwater harvesting

Rainwater harvesting in an industry

Rain Barrels harvesting rooftop rainwater

Bring it to a Storage

Storing in the Underground Tank

LEVELS !!!!

Ground Water Recharge

● Recharge Well● Deep Borewell Recharge● Recharge Trenches

Groundwater recharge : Wells & Borewells

Wells

`

The pit has reach the silt layer

Pit and concrete rings

Placing of the rings

Recharge Well :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

Schema Front Section - Recharge

Procedure • Locate recharge well in the channel or off

the channel

• Make arrangements to remove silt and leaves before water enters recharge well

• Monitor the rate of recharge and decide on the number of recharge wells necessary for the catchment

Don’t forget the maintenance

Borewells !

How does it look inside ?

Recharging directly into borewells

Need to be very very careful About water quality

Planning for RWH

Nature of Surface RWH Strategy

Rooftop Storage or Deep Aquifer Recharge

Paved Area / Roads Shallow Recharge – through trenches, Open Wells

Unpaved Areas / Garden

Shallow Recharge – through trenches, Open Wells

Sizing the RWH Structures

For Storage :

● Depending on usage and budget● Best to use existing storage structures● New storage structures can be sized for 30mm to 60mm rain

For Recharge : ● Calculate runoff for a 25mm-30mm rain and size accordingly

Designing

● Plot Size : 3000sqm

● Rooftop : 1500sqm,

● Non Rooftop : 1500sqm

● Rooftop Storage : 1500 litres filter and 36KL to 72KL storage

OR

● Rooftop Deep Aquifer Recharge :

● Non Rooftop 1500sqm – basic filters in drains and 1 recharge well or 5ft diameter and 30ft deep or Recharge Trench of 20KL capacity

Costs

S No Item Rate

1 4” PVC pipes – with fittings 80/- to 200/- per foot

2 6” PVC pipes – with fittings 280/- to 380/- per foot

3 Brick masonry storage/filter 10/- to 12/- per liter

4 Filter media 5/- to 7/- per liter

5 Commercially available filters - 500sqm

18,000/-

6 4KL Recharge Well 35,000/- to 40,000/-

6 16KL Recharge Well 85,000/- to 1,00,000/-

7 Deep bore with casing 30,000/- to 40,000/- for a 6” bore of upto 30m, 1000/- per meter

8 RCC storage 13/- to 18/- per liter

9 HDPE Storage (Sintex tanks) 6/- to 8/- per liter

10 Labour + Other misc 15% to 20% of material costs

Maintenance

● Keep the terrace/campus clean● Clean Storm water drains● Dont let water stagnate anyplace● Clean out the filters 2 times during the year● Clean the storage tank

Best Practices

● Metering the borewell

● Water Balance – Metering Demand and Supply

● Setup Rain Gauge

● Metering the harvested rainwater

Monitoring

● Water Quality

● Water Availability

● Depth to Water (below ground level)

● If the water is actually going into the borehole (rate of recharge) !!.

Biome Environmental Solutions Pvt Ltd (Rainwater Club)

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

HMT Layout, Vidyaranyapura, Bangalore – 560 097,

Phone : 080 41672790

Multi sourcing : Increasing urban reality(Case of Bangalore)

Piped Water : Cauvery River

• Unreliable/erratic ?• Scarcity• Infrastructure growth• Too cheap• 100km from B’lore• 500m below B’lore

Ground Water : Bore/Open well

• Drying up • Bad quality

Ground Water :Tanker Water • Availability ? • Quality ?• Cost ?

Bottled Water•Groundwater ? •Why ? • Is it really necessary or worth it ?

Waste Water Treatment

The product