Post on 01-Feb-2021
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Our Role in Better WaterManagement
Srikantha HerathEnvironment and Sustainable
Development ProgrammeUnited Nations University
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Outline
Water problems Water use Trends, consumption and Irrigation Floods - too much water
Communities Managing Water Decentralized approach Infiltration and Rainwater harvesting
Water Cycle and its changes Global water cycle Recovery of water cycle
Actions we can take for better water management Conserve water Adopt water harvesting methods Preserve local and water cycles Use ecological services
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How much water do we use?
We need water and our needs aregrowing
How much water do we use? How do we know if we do not have
enough water? Who is affected most?
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Agriculture
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Hunger, Food and Water by 2030
Hunger 800 million suffer
from chronic hunger
Population Additional 2 billion
by 2030
Food Need to increase by
60%
Water Agriculture use 70% of all water withdrawals (industry: 20%,
domestic: 10%). Daily drinking water 4 l/p Water for daily food varies between 2000 and 5000 litres.
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Irrigation
Agriculture Developing countries would increase
agriculture area from 202 million to 242million ha.
60% developing countries’ food comes from80% of arable land without irrigation
40% remaining food is produced in 20% ofirrigated land
Expansion of irrigation in the future will benecessary
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Agriculture Share in GDP in 1999 < 6%6-9%10-19%20-29%> 30%
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Hydrometerological
Geological
Biological
Water: Challenges to Development andSustainability
Water Scarcity W /Q Developing Countries Shared Water
Food Security Agriculture share 70% Low efficiency 25-
50% (GWSP) Developing countries
60% comes from un-irrigated 80% arableland. Balance from20% irrigated land
Water Quality Disasters
WaterScarcity1995Kassel U.
Hydro meteorological disasterscause the biggest losses amongall disasters – source ISDR
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Sustainability and DevelopmentMillennium Development Goals
At the Millennium Summit in September 2000 world leadersadopted the UN Millennium Declaration, committing their nationsto reduce extreme poverty and setting out a series of time-boundtargets, with a deadline of 2015, that have become known as theMillennium Development Goals.They are also basic human rights-the rights of each person on theplanet to health, education, shelter, and security.
Goal 1: Eradicate Extreme Hunger and PovertyGoal 2: Achieve Universal Primary EducationGoal 3: Promote Gender Equality and Empower WomenGoal 4: Reduce Child MortalityGoal 5: Improve Maternal HealthGoal 6: Combat HIV/AIDS, Malaria and other diseasesGoal 7: Ensu re Environmental SustainabilityGoal 8: Develop a Global Partnership for Development
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Goal 7: Ensure EnvironmentalSustainability
Target 10. Halve, by 2015, the proportion of people withoutsustainable access to safe drinking water and basic sanitation
Indicators30. Proportion of population with sustainable access to animproved water source, urban and rural (UNICEF-WHO)31. Proportion of population with access to improvedsanitation, urban and rural (UNICEF-WHO)
Target 9. Integrate the principles of sustainabledevelopment into country policies …..
Target 11. Have achieved by 2020 a significant improvement inthe lives ………
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Target 10, Action Area 1: Halve by 2015 theproportion of people without sustainable access tosafe drinking water.
This translates into reaching 210 millionpeople in 2005, 486 million people in2010 and 880 million people in 2015.
Access towater
LowLower middleUpper middleHighNo data
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Investment needs Financing achieving these targets is one of
the most important challenges to theinternational communities.
Cost – still not very clear: many estimatesat present
Water Supply and Sanitation CollaborativeCouncil and Global Water Partnershiphave estimated an expenditure of 9 – 30billion dollars a year (review of 10 reports).
Financial support at this level is notavailable at development agencies ornational governments.
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What is the real situation ?
Infrastructure not adequate to meet thedemand
Service providers with inadequate funds Infrastructure marked with resource
losses Conservative pricing of water services Ad hoc approaches – the “quick fix” not
working
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Paradigm ShiftParadigm ShiftE
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WHAT HAVE WE LEARNED ?
Technology alone is not enough Appropriate technology maximizes the value
of investments Innovative cost recovery programs are
essential to sustainable water and sanitationprojects
Community management is key to successfuloverall system performance
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Harvesting Rainwater
How did communities andindividuals been responding?
Rainwater harvesting examples
In the Takhar Province ofAfghanistan, snow is collectedin large baskets, which arethen transported by donkeycarts to communal silos forcompaction. Once full, theyare covered with soil forinsulation. A snow silo of 300cu. m. can supply a communityof 10 families for up to twoyears. (UNEP 1983, andGould: Rainwater catchmentSystems for Domestic Supply,1999)
Source: Rainwater Technology Handbook, Klaus W. Konig, Pub. Wilo-Brain
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Rainwater harvesting
Brick water duct to undergroundcistern in Cas Concos, Mallorca,Balearic Islands.
Average precipitation at 605mm/year, and population densityat 140/sq.km water is not thatscared in Baleric islands.However, the 7.5 million touristsper year who on the average aresaid to use 3 times the water theyuse at home make rainwaterharvesting a practical necessity.
Source: Rainwater Technology Handbook, Klaus W. Konig, Pub. Wilo-Brain
Rainwater harvesting
Miyake is a Japanese island of volcanicorigin located 200 km south of Tokyo.Water was traditionally fetched from springsthrough channels and stored in storagereservoirs or rainwater jugs or drums athome. Rainwater is harvested by extendinggutter pipe into a cistern. Another way nownot used much is to collect from treesthrough a network of channels.
Source: Rainwater TechnologyHandbook, Klaus W. Konig, Pub.Wilo-Brain
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Sri Lanka from MODISsatellite shows the reservoirsclearly as dark patches
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Rain-fed reservoirs in irrigationsystems
Number of reservoirs in Sri Lanka arerecorded as more than 30,000 in numbers in anarea of about 40,000 km2 built from around 5BC to 12 AD.
They are mainly found in the dry zone with ahigh seasonal variation and with an annualevaporation of about 1700mm
Facilitate the management of water for thepaddy cultivation in the dry zone for twoseasons per year.
MINNERIYA Tank(WEWA) Constructed in227 A.D
2,000 A.D
1,730YEARS
Later,irrigatingrice fields
Volume135,683,790 cu. m
Circumference
32 km
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Multi-functions of a village tank
The village tank also serves as thecommunity bathing place and plays animportant role as a place for socialgatherings.
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Feeder Canals the modern and the ancient A recent feeder canal
(top) that runs close tothe ancient feeder canal(bottom). The velocityis much higher in therecent construction andthe high embankmentsisolate the canal fromthe intermediaterunoff. In the ancientone flow is alongcontours andembankment is only onthe lower side enablingit to trap intermediateinflow.
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Water Cycle Stability of water environment is
important to our existence What happens to water?
Water does not perish. Recycles naturally. ItCIRCULATES WATER CYCLE
WATER CIRCULATION RATES areCRITICAL for OUR SURVIVAL Water Cycle is in a balanced state. If we
change one component it would affect theother parts. It can start a chain reaction andwe may not foresee the consequences
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Human activity impactsUrbanization and floods
Human activities alter the water cycle –knowingly or unknowingly: This canlead to unexpected consequences.
Urbanization is one of the best examples Frequency and magnitude of floods increase
How should we respond? By recovering the natural water cycle
Slow water flow Infiltrate water (recharge ground water)
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Restoring water cycle Similar systems applied to the whole
urban basins reduces floods andincrease infiltration: Can restore thewater cycle Hachioji new town example
Replacing drainage with infiltratingtype can off-set the adverse effects ofurbanization Case study:
Substituting the functions of naturalsystem – storage and infiltration – byartificial means could help in preservingthe original water cycle.
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Actions Conserve water, reduce waste
A number of European countries have succeeded inreducing water consumption
Practice rainfall harvesting and infiltration Adopt the use of infiltration systems to recharge
groundwater and reduce direct discharge as anintegral component of urban development.
Be conscious of water cycle and the try torestore it to original stable state. The natural stable water cycle will often be affected
by various human activities. It is necessary toestimate these changes and design measures torestore the original water cycle.
Use of ecological, natural systems formanaging water
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Institutions for linking Global to Local
Global Problems and solutions
Local Actions
Institutions totransform and
assess
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Thank You for your Attention
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Current global water use
0
1000
2000
3000
4000
5000
6000
1900 1940 1960 1980 2000Year
km
3/y
ear
Total use
Agricultural use
Industrial use
Domestic use
Source: Biswas (1977)
Global consumption has increased by more than 5 times since 1940’sdue to agricultural, industrial and domestic increases respectively.Increasing water demand over the past century are populationgrowth, industrial development and the expansion of irrigatedagriculture. Agriculture accounted for most freshwaterwithdrawal in developing economies in the past two decades.
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How much water do we use?
Consumption vary widely among differentcountries.
75 % of the population in Africa live on lessthan 40 l/d.
85% of the population in Asia live on lessthan 80 l/d.
Consumption in Japan is between 300 – 400l/d
Average consumption in USA is over 700 l/d Consumption is related to water availability
as well as economic state of a country.
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100
150
200
250
300
350
400
1960 1970 1980 1990 2000
Year
Aver
age
amount of
wat
er u
se p
er
per
son d
ay (
lite
r/per
son d
ay)
Water Consumption Change in Japan
Water consumption also change with time - economic development
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Water Stress
Water stress: According to onetheory, a country faces water stresswhen its annual supply ofrenewable freshwater is between1,000 and 1,700 cubic meters perperson. Such countries can expectto experience temporary or limitedwater shortages.
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Water Scarcity
Water scarcity: A country faceswater scarcity when its annualsupply of renewable freshwater isless than 1,000 cubic meters perperson. Such countries can expectto experience chronic andwidespread shortages of water thathinder their development.
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A widely used index for a macroscopic evaluation ofwater resources.
Rs = W / Q where , W : annual total water withdrawal
Q : annual available water resources
• Categorization of the extent of water scarcity ;
Rs < 0.1 : no stress
0.1 < Rs < 0.2 : low stress
0.2 < Rs < 0.4 : moderate stress
0.4 < Rs : high stress
Water Scarcity INDEXE
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Water Scarcity 1995Kassel U.
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Implications for the DevelopingCountries
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Population Population (Global Scenario)(Global Scenario)
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In 1950, 68% of the worldIn 1950, 68% of the world’’s population was ins population was in developing countries, and developing countries, and
32% was in developed countries32% was in developed countries
By 2030, it is expected that 85% of the worldBy 2030, it is expected that 85% of the world’’ss population will be in developing countries, and population will be in developing countries, and
15% in developed countries 15% in developed countries
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Population (Global Scenario)Population (Global Scenario)
Expected Growth (2000-2030): 2 billionExpected Growth (2000-2030): 2 billion
Mostly concentrated inMostly concentrated inUrban Areas of lessUrban Areas of lessDeveloped CountriesDeveloped Countries
1.9 billion in 20001.9 billion in 2000
to to
3.9 billion in 20303.9 billion in 2030
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What are the future trends ?
Renewable (rivers and lakes) waterRenewable (rivers and lakes) wateravailability per capitaavailability per capita
compared with 1950 (compared with 1950 (Shiklomanov Shiklomanov 2000)2000)
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Effect of urbanization
Increase flow speed Accumulate quickly Rainfallsof small duration can produce floods! More frequent
Reduction of infiltration Less ground water, less baseflow, water quality deterioration
Floods become more frequent and larger
Rainfall
InterceptionEvaporation
Transpiration
(Interception storage)
Evaporation(from soil)
Infiltration
Interflow
Unconfined Aquifer
Confined Aquifer
Human water useSupply
Drainage
What happens to Water ? (Rainfall and water supply)
Distributed Hydrologic Model...
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Urbanization and Floods
Reduction of retention and infiltration capacity of thebasin causes urban floods
Before UrbanizationAfter Urbanization
Flooding in Oomiya, SaitamaPrefecture, 1998
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Temporary storage of flood watersE
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Ground Storage at School Yard
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• Permeablepavement
• Permeableconnection box
• Permeable trench
Contribution to ;
• Flood runoffreduction
• Groundwaterrecharge andbase-flow increase
• Trap of non-pointsource pollutant
On-site Storm-water Infiltration FacilitiesE
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Effect of InfiltrationFacilities
Each point represent discharge forheaviest observed rain events
120100806040200
0
20
40
60
80
100
120
Q3 (mm)
Q2 (
mm
)
W
ith In
filtr
atio
n fa
cilit
ies
Without Infiltration facilities
0.45
• Tested two sites of similar characteristics
• In one site storm drainage pipes wereconverted to infiltration type and perviouspavements were provided.
• More than 50% reduction of flood runoff wasobserved.
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Source:
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Infiltration trenches andpond+trench use in Germany
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Association for rainwater storageand infiltration technology
An NGO formed in Japan about 15 yearsago to promote infiltration and rainwaterstorage.
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Atlantis Ecological Tank system
Association for rainwater storageand infiltration technology
Source’
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Rainwater harvesting examplesAccording to the regulationof Town of Remshalden,Germany, all new buildingsrequire installation ofseepage and percolationsystems for rainwater.Motivated by financial andeconomic consideration adeveloper decided to installrainwater utilizationsystems in town houses. Thesystem has beenprominently featured inadvertisements for the townhouses.
Source: Rainwater Technology Handbook, Klaus W. Konig, Pub. Wilo-Brain
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①Excavation andspreading geo-textile
②Installation ofplastic unit
③Plastic unit assembly
④wrapping by geo-textile
Source:
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Sinsin Block Foam Styrene(EUP) Ring Cycle
Aqua Pla Cross Wave System Honeycomb
Plastic Unit
Ecoro Wave (steel)
TUTTNew Trench Gio Box
Source:
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D-Raintank unit
H:400mmW:810mmL:860mm
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Installation procedure of D-Raintank
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Image of DRAIN-MAX system
GermanyINTEWA
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Measures to restore local water cycle
Hachioji New Town Project
Design: 1989-90Implementation: 92-96
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Physically baseddistributed hydrologic modeling
Rainfall
InterceptionEvaporation
Transpiration
(Interception storage)
Evaporation(from soil)
Infiltration
Interflow
Unconfined Aquifer
Confined Aquifer
Human water useSupply
Drainage
What happens to Water ? (Rainfall and water supply)
Distributed Hydrologic Model...
Rain
FlowSurface flow
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Three case studies 1. Infiltration/Storage in
Public 2. In Public + Private 3. In all feasible land use
classes Infiltration / Storage
systems restore the watercycle Reduce Floods Contribute to sustainability
Cautions Estimation of infiltration
capacities as well as theirbasin wide impact is acomplex task.
Groundwater protection aswell as precaution againstover recharge (salinity,flood control) should beconsidered
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和泉川流域図
●流域諸元 流域面積:11.5km2 流路延長:11.5km
東山の水辺
地蔵原の水辺
Source:
IZUMI RIVER, YOKOHAMA
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昭和30年代
平成8年
和泉川流域土地利用の変遷
●和泉川流域諸元 流域面積:11.5km2 流路延長:11.5km
市街地:約7%
市街地:約52%
凡 例
: 市 街 地
: 水 田
: 畑・荒 地
: 林・果樹園
Source:
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将来(2025年)の水収支
降雨100
地下水流出27
生活排水 0
蒸発散23
表面流出50
下水処理場へ
・市街化率約67%・地下水流出量が更に減少・表面流出量は5割・蒸発散量が更に減少
Source:
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和泉川流域水循環再生の行動計画目標
①「過去」(昭和30年代)の水量、水質を再生する。
②「過去」の清澄な湧水を再生する。
現在(和泉川下流の鍋屋橋付近) 概ね40年後(水循環再生後)のイメージ
Source:E
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Assessment of Hydrological System in Study AreaAnnual Water Balance ; Annual Preciptation 1586mm =100%
Annual Water Balance estimated by SHER Model
!"#$"!#% "$#"
!!#&
"'#%
()#%(%
""#*
"#)"%
"+#&
("#)
!'#' !(#% "+#&!(#"
$#$$#)$#)"#+
$#$
"$#$
*$#$
&$#$
)$#$
($$#$
("$#$
,-./012(+%% "$$$ "$*$23456./5
7./058-98,:/-8
3456
7./058-98,:/-8
;,54.2.<2=.9>.0805?@A
B-./013,58-2C5.-,D8 B-./013,58-2;876,-D8 C/-4-,54.0 B-8G2H,58-2I4:76,-D8
Source:
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Water CYCLE
Earth
Sky
Image:NOAA
Water Circulates inAtmosphere, surface andground
We do not lose water – it isin transition
Average time of stayAtmosphere
Tr = 12,900/577,000
= 8.2 days
Rivers = 17 days
Ground water 10,000 years
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Changes in Urbanizationof a suburb city:1990-1999
0
50000
100000
150000
200000
250000
300000
1991 1993 1995 1997 1999
Year
Incr
emen
t /Y
ear
(Sq.
m)
Total floor area New Construction Renovation
b
New construction: 1.2%dense residential areas,5.3% residential areasincrease
Reconstruction: 9% change
Converting existingdrainage toinfiltrating types canoffset the adverseeffects of urbanizationon urban water cyclein cities.
0
100
200
300
400
500
600
700
Evaporation Ovland Flow Recharge Interflow
Water Cycle Component
mm
/year
No Landuse Change
Landuse change
Landuse change with Infiltration Facilities
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GDP and Water Consumption
USA
Japan
Mean 214 L/p/c/d
European countries provide exemplary conduct in waterconservation practice. With awareness raising campaigns andlegislature, W. Germany has brought consumption to around 127l/d, Netherlands to 128 l/d and England to 150 l/d. Thesecountries are setting up exemplary standards with about 1/3 ofwater consumption compared to countries with similareconomies.
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GDP and Water Consumption
Mean 64 L/p/c/d
Lower Middle Low Income
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Domestic Water Consumption and GDP
In the past water consumption increased withGDP growth
Recently decrease of consumption because ofefforts due to ‘Sustainable DevelopmentConcept’
West Germany – 127, E.Germany – 100, Dutch128, England 150 l/p/d
New developments target about 112 l/p/d
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Campaign by ARSIT
Association for rainwater storageand infiltration technology
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平成17年度のPR活動
平成17年6月5日福祉バザー 平成17年6月11日南瀬谷 地域の集い
平成17年9月17日 和泉川水辺めぐり
出前講座 歩く様子 宮沢町会館雨水浸透ますの見学
Association for rainwater storageand infiltration technology
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