Clean Drinking Water Clean Drinking Water

Source for Source for CKDuCKDu Effected Effected

Areas through Rain Water Areas through Rain Water

Harvesting Harvesting

Tanuja Ariyananda, Tanuja Ariyananda,

DirectorDirector

Lanka Rain Water Harvesting ForumLanka Rain Water Harvesting Forum

RAINWATER RAINWATER HARVESTINGHARVESTING

COLLECTING RAINWATER WHEN COLLECTING RAINWATER WHEN

AND WHERE IT FALLS FOR USE AND WHERE IT FALLS FOR USE

DURING DRYMONTHSDURING DRYMONTHS

StorageStorage

RechargingRecharging

Traditional Rain Water HarvestingTraditional Rain Water Harvesting

Agriculture “tanks”Agriculture “tanks”

Open air collectionOpen air collection

Square brick tank collectionSquare brick tank collection

Tree trunk collectionTree trunk collection

Traditional Rain Water HarvestingTraditional Rain Water Harvesting

Uptake of Rain Water HarvestingUptake of Rain Water Harvesting

CWSSPCWSSP

Initiated in 1992 by WB and SL GovernmentInitiated in 1992 by WB and SL Government

Operated in 3 districtsOperated in 3 districts

Introduced RWH in 1995Introduced RWH in 1995

Designed 2 systemsDesigned 2 systems

Rural

CWSSP

Tanks

NERD LRWHF

Other RWH tanks

Piliyandala Colombo

Nugegoda Polgolla NWS&DB

Training Center

ADRAADRA -- Adventist Development & Relief Agency Adventist Development & Relief Agency Sri LankaSri Lanka

Asia Asia OnlusOnlus --

BLIABLIA -- Buddha's Light International AssociationBuddha's Light International Association

Care InternationalCare International

CWSSPCWSSP -- Community Water Supply &Community Water Supply & Sanitation Sanitation ProjectProject

EkamuthuEkamuthu CultivatorsCultivators

GTZ GTZ -- GTZ GTZ

HKL HKL MenikeMenike

IOM IOM --

Practical ActionPractical Action

KOPBMO KOPBMO -- Kala Kala OyaOya River Basin Management River Basin Management OfficeOffice

LRWHFLRWHF-- Lanka Rain Water Harvesting ForumLanka Rain Water Harvesting Forum

NCCNCC -- National Christian CouncilNational Christian Council

NGO Water Supply and Sanitation Decade ServiceNGO Water Supply and Sanitation Decade Service

NWS&DB NWS&DB -- National Water Supply & Drainage National Water Supply & Drainage BoardBoard

ORDEORDE -- Organization for Resource Development Organization for Resource Development and Environmentand Environment

OXFAM OXFAM

PALM FoundationPALM Foundation

Plan Sri LankaPlan Sri Lanka

PRDA PRDA -- People’s Rural Development AssociationPeople’s Rural Development Association

SarvodayaSarvodaya ––

SDA SDA -- Southern Development AuthoritySouthern Development Authority

USIP USIP -- Urban settlement Improvement ProjectUrban settlement Improvement Project

WV WV -- World VisionWorld Vision

Distribution of Rain water Harvesting Systems in Sri LankaDistribution of Rain water Harvesting Systems in Sri Lanka

Basic components of Roof RWH Basic components of Roof RWH

systemsystem catchment or surface to catchment or surface to

collect water.collect water.

delivery system to delivery system to transport the water from transport the water from the catchment to the the catchment to the storage reservoir.storage reservoir.

storage reservoir or storage reservoir or tanks to store the water tanks to store the water until it is used. until it is used.

aan extraction device.n extraction device.

Rain Water QuantityRain Water Quantity

mm

Runoff coefficient =04-0.9

evaporation

Roof run off = Catchment area (mRoof run off = Catchment area (m22 )x Rain fall m x Run off coefficient)x Rain fall m x Run off coefficient

= 50 m= 50 m2 2 x 1000mm x 0.8x 1000mm x 0.8

= 40 m= 40 m3 3 = 40,000 liters= 40,000 liters

Roof run off = Catchment area (mRoof run off = Catchment area (m22 )x Rain fall m x Run off coefficient)x Rain fall m x Run off coefficient

= 50 m= 50 m2 2 x 1000mm x 0.8x 1000mm x 0.8

= 40 m= 40 m3 3 = 40,000 liters= 40,000 liters

Leakage, overspill

Mean rainfall m/a(m, d)

Calculating Roof rainwater run off

QUANTITYQUANTITY

Jaffna

Mannar Jaffn

a

Puttlam Jaffn

a

Anuradhapura Jaffn

a

Trincomalee Jaffn

a

Batticaloe

Wariyapola

Kandy

Colombo

Galle

Hambantota

Pellwatte

Ratnapura

Nuwara Eliya

Bibile

Badulla

Wattawala

Minneriya

How to calculate what capacity Rain Water Harvesting Tank you need

Click on the nearest climatic zone to your location

Read from table below according to your roof size and service level

you require

Colombo Zone

Tank Size m3

3 5 8 10 15 20 25 30 40 50

Roof Size m2

Minimum Daily Service level ( liters)

50 50 60 75 80 90 95 98 100 105 110 100 70 90 125 130 150 160 175 180 195 200 150 85 115 145 170 195 225 235 250 275 280 200 95 130 170 190 238 255 280 305 335 360

Hambantota Zone

Calculation of RWH tanks capacity for

Different Climatic Zones in Sri Lanka

Tank Size m3

3 5 8 10 15 20 25 30 40 50

Roof Size m2

Minimum Daily Service level ( liters)

50 46 65 80 98 115 125 130 133 138 140 100 55 80 115 130 170 197 220 233 253 270 150 60 82 130 153 195 240 170 195 330 357 200 68 95 135 168 220 260 305 335 392 435

Anuradhpura zone

Rain Water Quality: How Rain Water Quality: How Rain Rain

water can get contaminatedwater can get contaminated AtmosphereAtmosphere

RoofRoof

TankTank

ExtractingExtracting

Microbiological

contamination

Chemical

contamination

Carried by

vector Blown dust

Rooftop

Direct Entry

into tank

Residence in

the tank

Carried by water

entering the

tank

Washed out

of air

Tank outlet

Ingestion

tank environment

First flush

Filters

Overflow diversion

Inlet arrangements Screens

Screens

Outlet arrangements

Post-tank processing

Roof environment

Environmental reduction

Barriers

0

1

10

100

26/Aug 26/Sep 26/Oct

E.C

oli

(C

ou

nt/

100m

l)

0

10

20

30

40

50

60

Rain

fall

(m

m)

Rainfall E.Coli

Microbiological contamination

Roof Contamination PreventionRoof Contamination Prevention

flush out the first 2.5 mm of rainfall

Different fist flush usedDifferent fist flush used

1 2

3

Water Quality Water Quality SSurvey Resultsurvey Results Tank No. Name of beneficiary Village Roof type pH

Conductivity (

µs/cm)

TDS ( mg

l-1)

Salinity

(ppt) Temp ( OC)

E.Coli (

per 100

ml) Date sampled

43-154 T. Gneshan Thallikulum Tile 10.1 6.69 47.1 33.6 2 19/11/2012

43-153 K. Saroja Deva Thallikulum Asbestose 9.9 114.5 79.9 57.1 0 19/11/2012

43-193 Markandu Thallikulum Tile 9.9 57.6 82.3 41.1 1 19/11/2012

43-152 Pushparasa Nalini Thallikulum Tile 9.6 76 54.3 108.6 39 19/11/2012

43-169 R. Thevarsa Thallikulum Tile 10.3 143 100.1 71.8 1 19/11/2012

43-159 Marimuthu Thallikulum Tile 10.6 176.6 123.5 88.3 0 19/11/2012

43-162 Nahamuthu Letchimi Thallikulum Tile 9.9 140 98.2 70 32.7 0 19/11/2012

43-157 Rasiyah Thevarajah Thallikulum Tile 11.1 348 243 172 28.8 0 19/11/2012

43-165 R. Ramaskrishna Thallikulum Tile 8.9 154.2 107.7 77 29.8 120 19/11/2012

43-184 Subramanium VishawanathanThallikulum Tile 10.3 160.8 112.9 80.9 29 0 19/11/2012

DW Sudakesvaran Thallikulum 7.4 865 608 437 520 19/11/2012

43-051 Baliyah Srirampura Asbestose 9.1 107.5 75.2 53.4 24.6 1 20/11/2012

43-052 M. Arudsgivaran Srirampura Asbestose 9.3 344 240 171 24.7 2 20/11/2012

43-124 Rukamani Devi Srirampura Asbestose 8.9 112 78.4 56 26.5 3 20/11/2012

43-118 Murughan Jaydevi Srirampura Asbestose 9.1 120.5 84.6 60.3 28.2 100 20/11/2012

43-076 Kokilarajah Srirampura Asbestose 9.2 290 204 148 28.7 14 20/11/2012

43-114 S. Parawathi Srirampura Asbestose 9.2 107.2 75.2 52.7 28.5 100 20/11/2012

43-087 Muna Selvanatha Srirampura Asbestose 9.3 91.7 63.7 45.7 28.5 100 20/11/2012

S2 Parameshwarna VidayalayaAnnanagar Tile 9.6 81.3 57 41 26.8 3 20/11/2012

43-150 Ganeshan Annanagar Asbestose 9.7 113.2 79.2 56.7 29.8 15 20/11/2012

DW Pushpaswari Srirampura 7.4 648 454 324 26.6 2 20/11/2012

TW Thirugnanasampathai VidayalayaSrirampura 6.7 659 456 329 9 20/11/2012

TW Parameshwarna VidayalayaAnnanagar 6.9 489 342 244 29.5 100 20/11/2012

WHO guideline for drinking water 6.5-8.5 1000 0

SL Standards for drinking water quality ( Max. desirable level) 7-8.5 750 500 100 0

Improvement of Quality in a Rain Improvement of Quality in a Rain

water systemwater system

Good O&M and awareness Good O&M and awareness raisingraising

First flush and inlet filterFirst flush and inlet filter

Lid/Cover Lid/Cover to prevent algae to prevent algae formation and insect formation and insect breedingbreeding

Prevent metal contamination Prevent metal contamination from rooffrom roof

Simple treatment of drinking Simple treatment of drinking water water ( ( boiling)boiling)

Location : Vavuniya District

Raise awareness among Officials and Beneficiaries.

Demonstrate methods of provision of clean drinking

waterfacilities for IDP returnees in resettlement areas

750 rain water harvesting system in resettled

households

develop their home gardening

establish 10 plant nurseries

9 rain water harvesting systems for schools and

hospitals.

Creating a pool of trained masons (10) on

constructing RWH systems.

Training Plant Nursery farmers

Water Security for Resettlement Areas in the Northern Province of Sri Lanka

through Rainwater Harvesting

Reasons for not using RWHS

Rain Water Usage HouseholdRain Water Usage Household

Utilization of Rain Water Harvesting Systems

-- After the projectAfter the project

0

10

20

30

40

50

60

70

Drinking Cookoing Washing Bathing Toilet use Gardening Other Not Mention

Wet season

Dry season

Rain Water Usages

Lanka Rain Water Harvesting ForumLanka Rain Water Harvesting Forum

Never used it 0%

Used initially not

anymore 7%

used only raininy

season 4% filled with bowser

water 2% Use all the

time 24%

Use whenever

water available in

tank 52%

Not recorded

11%

7 %

Utilization of Rain Water Harvesting Utilization of Rain Water Harvesting

Systems Systems ( National Survey 2011( National Survey 2011

Never Used

8% Used at intial

stages, not now15%

Used in Wet

Season21%

Used to fill water

from other water sources

28%

Used aroud the

year28%

Reasons for the Use of Rainwater Reasons for the Use of Rainwater

1.1. No alternative water sourcesNo alternative water sources

2.2. Drying up of alternative water Drying up of alternative water sources during dry periodssources during dry periods

3.3. Convenient to use at Convenient to use at homesteadhomestead

4.4. Prefer to use rainwaterPrefer to use rainwater

5.5. No one available in the No one available in the household to carry water household to carry water from outsidefrom outside

6.6. No cost involvedNo cost involved

7.7. Low quality of water in the Low quality of water in the alternative water sourcesalternative water sources

8.8. Other reasonsOther reasons

National Survey 2011

Reasons for not Using Rainwater Reasons for not Using Rainwater

Harvesting Systems Harvesting Systems

1.1. Incomplete constructionIncomplete construction 2.2. System is not functionalSystem is not functional 3.3. Harvested water is not sufficientHarvested water is not sufficient 4.4. Do not like Do not like to use rainwaterto use rainwater 5.5. Un acceptable Un acceptable colourcolour of waterof water 6.6. Water leakage in the tankWater leakage in the tank 7.7. Entry of other fauna into the Entry of other fauna into the tanktank 8.8. Have a wellHave a well 9.9. Have pipe waterHave pipe water 10.10. Other reasonsOther reasons

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1 2 3 4 5 6 7 8 9 10

2.87

27.60

7.53

14.70

1.08

4.30

19.71

7.89

16.49

10.39

Pe

rce

nta

ge

Reason

O&M

Social

Technical

National Survey 2011

Average Duration of Rainwater Use (As Average Duration of Rainwater Use (As

Perceived by % of Beneficiaries)Perceived by % of Beneficiaries)

3

27

43

8

13

6

1

2623

30

19

1

0

5

10

15

20

25

30

35

40

45

50

<1 month 1-3 months

4-6 months

7-9 months

10-12 months

>12 months

% o

f P

eo

ple

Dry Zone Wet Zone

National Survey 2011

Cost of Rain Water Harvesting

Tank System

Tank Type

Estimated Cost in Rs. Tank size m3

3 5 8 10 20 30 50 Ferrocement 30,000 50,000 60,000 70,000 200,000 300,000 500,000

Plastic 37,500 55,000 100,000 Brick under ground*

40,000 45,000 50,000 90,000

Partial under

ground*

45,000 50,000 60,000 120,000 200,000 300,000

*Does not include labour cost for digging

•Legislation: Amendment of UDA by laws

to incorporate RWH April 2009

•15th SAARC Declaration, August

2008

…. at the looming global water crisis, recognized that

South Asia must be at the forefront of bringing a new

focus to the conservation of water resources. For this

purpose they directed initiation of processes of building

and encouraging of research, combining conservation

practices such as rain water harvesting, water

conservation……

•Amendment to Urban Development

Authority Drainage Act No.36, of 2007

published by gazette September 2007

•Kandy Declaration, by SAARC Ministers,

September 2007

……Signed by 5 minister of SAARC to promote

RWH in their prospective countries

•National Rain Water Policy and

Strategies, June 2005 . . aimed at encouraging communities to control

water near its source by harvesting rain water

Policy and Legislation

Rain water Harvesting : SolutionRain water Harvesting : Solution

To achieve To achieve MDG MDG for Water Supply & for Water Supply &

SanitationSanitation

Climate Adaptation Climate Adaptation for drought and for drought and

floodsfloods

Reduce Reduce health problems health problems due to drinking due to drinking

contaminated watercontaminated water

flourosisflourosis and kidney problems and kidney problems

Urban areas Urban areas reduce expenditure reduce expenditure on on

water and energy and to control floodswater and energy and to control floods