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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
Recommended