WaterRainwater harvestingRebuilding an urban

water cultureAvinash Krishnamurthy

Biome Environmental Trust

Rani ki Vaav800 years

ago

Vijayanagar Kingdom – 500 years ago

Surangas – living history (from persia 500 years

ago)

Bangalore – living history (100 years

old)

Photo : Norma Angelica Hernandez Bernal

Ultimate source of all water :

RAIN

Twin problemsUrban FloodingWater Scarcity

How much water do I use ?

Use Litres/person

Drinking 3

Cooking 4

Bathing 20

Flushing 40

Washing-clothes 25

Washing Utensils 20

Gardening 23Total 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 to do Rainwater Harvesting ?

1. Catchment2. Conveyance3. First Rain separator4. Pre-Filter5. Storage / Recharge6. Point of use Treatment

Rainfall pattern in Mysore

MONTH DAYS QUANTITY (mm)

JAN 0.2 1.9

FEB 0.4 5.2

MAR 0.5 8.5

APR 3.9 61

MAY 7.4 148.3

JUN 5.6 72.7

JUL 8 80.4

AUG 5.7 63.7

SEP 6.3 106.2

OCT 8.9 166.5

NOV 3.6 58

DEC 1.1 16.5

TOTAL 51.6 788.9

Rainfall pattern in Bangalore (970mm annually, 60 rainy days)

How much water from the terrace ?Site size

Terrace area

Amount of water for one 30mm rain

30*40 ft 900 sq ft (900 sq ft * 0.9 * 30mm)------------------------------- (3.3 * 3.3)

= 2231 litres Coefficient of runoffTerrace absorbs waterDepends on material

Quantum of rainTerrace Area

To get litres

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 / annumWho 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 isAlmost 50% of a household’s needs !!!

Can we capture this store it or recharge it into our borewells (or can we do rainwater harvesting) ?

….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

A clean roof means clean water

Join all the pipes……

Bring it to a Storage

Clean Rainwater :FRS & Filtration

First rain separation – let the rain clean the roof

Filter

Rain barrel : easiest way to begin rainwater harvesting

Storage

LEVELS !!!!

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

LEVELS !!!!

Schema Front Section - Recharge

Borewells !

How does it look inside ?

Recharging directly into borewells

Need to be very very careful About water quality

Capital cost – in Bangalore

• Piped water supply :1,500 Million Litres per Day

• Rainwater :

close to 2,125 Million Litres per Day

Rainwater harvesting and Building bye-laws

Implementing Rainwater harvesting: • Key instrument building bye-law ?• How do you ensure effectiveness of

implemented projects ? (technical standards)• How do you incentivize people who adopt it?

(Can you tie it up with tariffs, property tax etc? – the importance of metering)

• How do you monitor effectiveness ?

Bangalore : An example

Two laws –1. Building bye-law in 2005 (BBMP implementer)2. Amendment of BWSSB Act 2010 (BWSSB

implementer)3. Imposed on all properties that will be built

30*40ft and more4. Applicable to already built buildings (as of

2010) 60*40ft and above

Bangalore: An example

5. Technical standardsEvery square meter of roof area : 20 L

storage/rechargeEvery square meter of non paved area : 10 L of

recharge(i.e. a 20mm design – captures 80% of rain for

Bangalore)

6. Incentives & monitoring ineffective (?)

CASE STUDY : RAINBOW DRIVE

Location Sarjapur Road, Bangalore – Ground water stressed area

Size 34 acres, approx 350 plots, 200 occupied

Details Currently governed by Plot owners association (Society) since 2002.No BWSSB connectionDependent on Ground water ( owned bore wells)

Entrance:Prone to FlashFloods during

Rain

WATER SUPPLY - SOURCE

Currently Yielding Borewells Currently 2 such borewells

Over last 6 years 4 Borewells dried

One in this photo was highest yielding borewellAround 2 years back – now totally dry.

…….and Individual homes calling Tankers when layout supply not enough!!!

WATER SUPPLY - DISTRIBUTION

Two Centralised overhead tanks withPiped connection to Each household.Infrastructure Owned, Managed and Operated by Plot owners association

Every household connection METERED !!!!

WASTE WATER & SANITATION

Two STPs given by the builderSTPs functioning questionable

What to do with “treated” waste water?

Infrastructure Owned, Managed and Operated by Plot owners association

SUMMARY OF KEY PROBLEMS

•Increasing water insecurity – borewells drying up.

•Community as a whole not aware of the problems – wasteful consumption

•Water Tankers not reliable.

•Flash flooding at entrance during heavy rains

•STP output water stagnating at entrance drains

IUWM INTERVENTIONS – FOUR PHASES

Phase Purpose Activities Results

Phase I Problem diagnosis, Getting people on board

Data collection, communication to people

Water literacy and problem statement

Phase II Ground water and Demand management

Sourcing expertise, Implementation of RWH

Kick off of RWH at HH and collective level

Phase III Ground water and Demand management

Finalising new Tariff regime, continued investment in RWH

Second phase of RWH and New Tariff regime

Phase IV Waste Water management

Yet to start Intended to improve treatment and reuse waste water for landscape

GROUND-WATER MANAGEMENT : RECHARGE

Land use % land area

Roof-tops 60%

Roads 25%

Open spaces 15%

Means Strategy for layout :1.First target roof tops (Use Common areas to demo)

2. Target Roads and storm water drains

RECHARGE WELLS – THREE TYPES

Wells in Storm water drains invested in by RWA

(Collective Investment)

Wells in Storm water drains invested in by House hold (Just outside the house - individual Investment)

Wells inside the House(individual Investment)

Resulted in reduced flooding leading to greater supportTotal of 38 recharge wells in 34 acre layout already completed.

Highest well density in Bangalore !? – starting of project

NOW 150 recharge wells across 300 houses. No private borewells !

About Recharge wells

About Drain management

About Catchment management

New Water Tariff Policy – Increasing block tariff based on production costs (Rs 16 – 17 / KL) understood during Phase I

• Households invested in recharge at Household level get Rs 100/- discount on bill!

• Monthly Billing, not Bi-monthly any more !• Rs 10/- per day fine for late payments !• No supply of water to construction sites!

Consumption slab Tariff

0 – 10 KL Rs 10/-

10 – 20 KL Rs 15/-

20 – 30 KL Rs 25/-

30 – 40 KL Rs 40/-

> 40 KL Rs 60/-

DEMAND MANAGEMENT : REVISED TARIFF REGIME

DEMAND MANAGEMENT : HH RWH

PIONEER SPEAK

“ An Organized Minority is a political Majority – Jesse Jackson• Few people with conviction can provide the spark to mobilize the inactive majority in the community.• Analytical approach to price resources accurately and reward conservation and penalize wastage is critical• Non-interference from government, empowerment of the community to manage its resources is the key ”

- Jayawant BharadwajManagement Committee member and Key driver of RBD’s Water Reforms

IUWM INTERVENTIONS – RESULTS

Immediate Impact observedNo Flooding during 2008 monsoon despite heavier than

normal monsoon.People keeping track of their bills and consumption:

Far less hosing of cars prevalent than beforeFixing of leaky pipes, valves, tanks

Biome Environmental Trust

(Rainwater Club) avinash@biome-solutions.com

www.rainwaterclub.orgwww.biome-solutions.com

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 ?