Rainwater Harvesting and groundwater recharge

In urban centres – experiences from the field

Avinash Krishnamurthy, Nathan Stell,

Shubha Ramachandran, Sunil M S, Karan Singh

Biome Environmental Solutions Pvt Ltd

(Rainwater Club)

The Urban Context

Bangalore

Bangalore gets its water from the Cauvery 95 kms and 500 meters below thecity

Bangalore need : limitations

• Production cost of water is very high at Rs 24 a kilo-liter.

• Ceiling on the availability : 1,500 mld. Good enough for 7 million people only i.e. by the year 2011.

• Surface and groundwater on the decline.

Water supply and sources in Bangalore

• Piped water supply :Current Demand : 1,500 Million Litres per DayInvestment Rs.60,000 million ($ 1500 million)Supply : Around 900 MLDShortage covered by : Ground Water !!!

• Rainwater :3,000 Million Litres per DayRs. “0.00”(zero) ?

Can a better balance be reached ??

Peripheral and Ribbon growth

Urban Water Markets !

Urban Water Markets !

Case Studies

Working in the residential contexts

Jyoti Meadows Apts

44 households, 33KL/day demand

Source: Utility supply, tankers and borewells

Motivation for RWH: Increase in connection size from utility

After RWH New Sources:Rooftop water, Shallow Aquifer

Roof area: 700 sqm

Rainfall endowment : 6.7 million liters / annum (200 days of

demand)

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.

Shallow aquifer at 10ft depth !!!

• Earlier used only borewells/tankers

• Now Rainwater and shallow well water

• Rainwater tank used as multi-storage

Borewell depths :

600 ft, yields not measured, not metered

Shallow aquifer water

(cheapest: Rs 3 / KL)

Now new source of water – yield around

500 litres per pumping - summer

1000 litres per pumping - monsoon

Recuperation

4 days during summers

2 days during monsoon

Tata Sherwood

376 households, 200KL/day demand

Source : Borewells – 6 of them

Motivation for RWH: groundwater dependence

Roof area: 11000 sq m

Rainfall endowment : 10.6 million liters/annum (53 days of demand)

Existing storm-water tanks

Existing storm-water tanks

Borewell Details:Not being used currently due to “motor” problems650 ft in depth, 6 inch diaRecharge Details:Well around borewell – 7ft dia, 22 ft depth (capacity approx 20,000 lts)Borewell casing perforated – so direct aquifer recharge

Recharge rate: 20,000 litres / hour !Need to monitor impact on water quality and yields of other borewells !

Rainbow Drive

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

Details

34 acres, approx 350 plots, 220 occupiedSize

Sarjapur Road, Bangalore – Ground water stressed areaLocation

Entrance:

Prone to Flash

Floods during

Rain

•Increasing water insecurity – borewellsdrying 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

WATER SUPPLY - SOURCE

Currently Yielding Borewells

Currently 3 such borewells, one of them low yield.

Over last 6 years 3 Borewells completely dried

One in this photo was highest yielding borewell

Around 2 years back – now totally dry.

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

INTERVENTIONS – FOUR PHASES

Intended to improve treatment and reuse waste water for landscape

Yet to startWaste Water management

Phase IV

Second phase of RWH and New Tariff regime

Finalising new Tariff regime, continued investment in RWH

Ground water and Demand management

Phase III

Kick off of RWH at HH and collective level

Sourcing expertise, Implementation of RWH

Ground water and Demand management

Phase II

Water literacy and problem statement

Data collection, communication to people

Problem diagnosis, Getting people on board

Phase I

ResultsActivitiesPurposePhase

Currently used borewells

Currently un-used borewells

Recharge structures:

Orange dots – 3ft * 10ft recharge wells

Red dots – 3ft*20ft recharge wells

Blue dots – 5ft * 30 ft recharge wells

55 Wells in 34 acres

1,98,000 litres of holding volume

Overhead Water towers

Recharge Well – 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)

Demand Management : Household RWH

Only about 20 houses so far covered – lots to go

Every household connection

METERED !!!!

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!

Rs 60/-> 40 KL

Rs 40/-30 – 40 KL

Rs 25/-20 – 30 KL

Rs 15/-10 – 20 KL

Rs 10/-0 – 10 KL

TariffConsumption slab

Demand Management : Revised Tariff Regime

Monitoring

Thanks to the Arghyam Foundation, Bangalore, Biome has now just begun a comprehensive monitoring exercise with the RWA to :

1. Monitor and Document impact of interventions over 1 year2. Evolve a Best Water Management practices document for layouts3. Evolve “List of Questions housing consumers should ask developers”

Summary of key metrics

Currently no treated waste-water reuseCurrent garden areas are water intensive (lawn based)

24.5 sq m / capita39 sq m / capitaPer capita road area

59 sq m / capita61 sq m / capitaPer capita roof area

20 ML per annum20 ML per annumRainfall runoff from roads (25% land use)

72 ML per annum47 ML per annumRainfall runoff on rooftops (60% land use)

133.23ML per annum133.23 ML per annumTotal rainfall endowment

300 KL/day 127 ML per annum

200 KL/day84 ML per annum

Demand (220 lpcd)

@ full occupany@ current occupancy (65%)

Learnings – Three dimensions

People’s participationProcess

Knowledge

People’s participation• Mixture of short-term self-interest, longer-term

collective interest & “green thinking”. Laws help.• Collectives around property boundaries – best

scale of intervention seems at the (HH level + RWA level) – better catchment control

• Tend to equate RWH with Borewell recharge• Collectives have “champions” who drive the

whole process. The champions role is very critical.

• Characterized by low water literacy

Process• Direct dialogue with community• Collectives have “champions” who drive the

whole process. The champions role is very critical.

• Urban citizenry characterized by low water literacy. The process is one of increasing “water literacy”

• Need to integrate services into the process for intentions to convert to actions

KnowledgeChallenges :• integrate many knowledge streams • Human capital along the entire chain – from

dialogue to implementation

Learnings :• Best is the enemy of the good• Opportunity for new knowledge generation

Biome Environmental Solutions Pvt Ltd and Rainwater Club

water@biome-solutions.comwww.biome-solutions.com

1022, 1st floor, 6th Block,HMT Layout, Vidyaranyapura,

Bangalore – 560 097,Phone : 080 41672790

A Large premier educational institution

What is the technical framework ?What is the overall framework for ecological understanding?

Integrating Knowledge of different types,

using the opportunity for continuous new knowledge generation

What should the legal framework be?What should the institutional framework be?What are the financial sustainability issues?What do social constructs such as RWA mean for the above ?

People’s participation,

scales of decentralisation,

Knowledge and Services delivery

Questions for discussionsLearnings

WaterTank

WaterTank

STP

Club House

Borewell 1

Water Softener

Borewell 2

Borewell 3

1. Developer buys land

2. Developer develops infrastructure

3. Developer markets to consumers

4. RWA formed after critical occupancy

5. Transfer of ownership of common areas to RWA

6. RWA completely takes over management.

Developer leaves the scene

Common areas : Roads, bore wells,

Water tanks, STP, Club house etc

RECHARGE WELL - SCALABLE & PLUGGABLE

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 Bharadwaj

Management Committee member and Key driver of RBD’s Water Reforms

The Media loved this story…

• “Water supply bottom up” on http://bangalore.citizenmatters.in/

• The Times of India, Vijaya Karnataka, The Hindu, Live Mint

• Four part Series of “How to achieve RWH in IUWM context for Gated Layouts” in http://bangalore.citizenmatters.in/

• Featured in the TV by local kannada channels

The Team

Mr Nathan Stell,

Biome, lead investigator

Of the Monitoring Exercise at RBD

Mr Vishwanath S, Biome,

Mentoring and Guidance

Mrs Shubha Ramachandran,

Project Manager, Biome

The design and implementation of RBD was anchored by Shubha and Sunil

Mr Muniyappa and his Well Digging team

Mr Chitti Babu and MrNarayanaswamy and their

Plumbing Teams

Mrs Chitra Vishwanath and the

Architecture team at Biome !!!

Mr Sunil M S,

Project Manager, Biome