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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

Sri LankaE

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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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