rainwater harvesting - global water for sustainability

8/9/2019 Rainwater Harvesting - Global Water for Sustainability

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Rainwater Harvesting

EVR 5332 Integrated Solutions forWater in Environment and

Development

November 5, 2007

John Stiefel Research AssistantGlobal Water for Sustainability (GLOWS) Program

Florida International University


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Rainwater harvesting (RWH):

= the collection and storage of rainwater insurface or sub-surface reservoirs, therebyreducing water losses to runoff and evaporation

(1) the direct capture and storage of rainwater for future humanuse

(2) manipulation of the landscape to slow and harness runofffrom rainfall


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Rainwater harvesting in arid areas

Map courtesy of United States Geographical Surveyhttp://pubs.usgs.gov/gip/deserts/what/world.html
http://pubs.usgs.gov/gip/deserts/what/world.htmlhttp://pubs.usgs.gov/gip/deserts/what/world.html


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RWH in highly seasonal climates


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INDIA:the worldsleader in

RWH
http://images.google.com/imgres?imgurl=http://www.cnn.com/2000/ASIANOW/south/08/01/india.rain.ap/story.india.rain.jpg&imgrefurl=http://www.cnn.com/2000/ASIANOW/south/08/01/india.rain.ap/index.html&h=168&w=220&sz=12&hl=en&start=33&tbnid=xShvySCY-MRxvM:&tbnh=82&tbnw=107&prev=/images%3Fq%3Drain%2Bindia%26start%3D18%26ndsp%3D18%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN


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Rooftoprainwaterharvesting


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Anicut


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Anicut


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Nadi / Johad

Source: adapted from Sukhija et al., 2005

T k


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Tanka

L d b di / il b di


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Land bunding / soil bunding


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RWH is a technology that can be applied in bothurban and rural areas

Several RWH approaches have been used and

many may be climate or eco-region specific

RWH can be implemented and managed at

various levels City level

Village level

Household level

RWH in an IWRM context


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Many international organizations and

governments are promoting RWH as astrategy for improving access to watersupply

Example: seasonal variability in water supply

RWH is being applied to demonstratecorporate social consciousness and as asolution to conflicts Example: groundwater mining


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The case of

Coca-Cola Environmental and

social problems in India;

intense use ofgroundwater

Criticism on the basis ofclaims that thecompany is depletinggroundwater resourcesto make Coke 9L of water = 1L of Coke

Many people are angry

and want Coke out ofIndia


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Coca-Colas response

In June 2002, began implementing RWH as awater conservation program Specific objective was to increase groundwater

recharge

By 2006, had RWH programs at 26 bottlingplants in India and in 9 communities

Claim to have harvested 1.65 million m3rainwater in 2005 Amount corresponds

to 56% of groundwaterwithdrawn by Coke inthat year

Plans to expand RWHinitiatives throughout IndiaSource: BusinessWeek 2/10/2003


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Considerations:

Rooftop rainwaterharvesting

Pros and cons? Pros:

Can provide a clean watersource, especially in urban

areas Can decrease urban

flooding

Groundwater recharge

increased through artificialrecharge

Cons:

Should not be a substitutefor a solution to problemsof surface water quality


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Considerations:

land and soilbunding

Pros and cons? Pros: Decreases runoff and

makes water available for

agriculture Cons:

Causes majormodifications to the way

water moves through thelandscape

Could deplete surfacewater resources in

downstream areas

C id ti RWH f


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Considerations: RWH forgroundwater recharge

Pros and cons? Pros:

Can recharge shallowaquifers

Cons: Traditional RWH doesnt

recharge water indeeper, confinedaquifers

Downstream impact

Few scientific studieshave actually examinedthe effectiveness ofRWH for groundwaterrecharge


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SUMMARY RWH is an old technique used to capture and store

water for human use

Used to improve access to water supply especially inarid regions or highly seasonal climates

Cost-effective and applicable at many scales;decentralized in nature

Needs to be considered alongside other approaches for

water supply and storage, and in an IWRM context

A need more information on the groundwater rechargedynamic of RWH.


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THE EFFECTIVENESS OF RAINWATER HARVESTING FORTHE ARTIFICIAL RECHARGE OF GROUNDWATER IN THE

WAKAL RIVER BASIN, INDIA

John M. Stiefel Research Assistant

Global Water for Sustainability (GLOWS) Program

Florida International University

Masters Thesis Research


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Study Area

The Wakal River Basinoriginates at an altitudeof 762 m in the Aravalli

Hills of southernRajasthan

Catchment area of 1,625km2

Source of the greaterSabarmati River Basin

Trans-boundary riverflowing 371 km throughRajasthan and Gujaratbefore discharging into the

Arabian Sea

W t S it i R j th


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Increasing demand for water has led to over-exploitation of the groundwater resources Only 32 of the 236 blocks (sub-districts) in

Rajasthan are categorized as safe, with respect totheir groundwater resources

General decline in the water table Increase in groundwater quality problems

Groundwater is the primary source ofreliable water supply in Rajasthan 90% of the drinking water and 60% of water

used for irrigation

Water Scarcity in Rajasthan

Rajasthan is Indias driest and mostdrought prone state 10% of Indias geographic area, along with 5%

of its population, yet it contains only 1% of the

nations total surface water resources

K l d G


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Knowledge Gap

Rajasthan and Gujarat have been at the center of a majorgrassroots mass movement to revive rainwater harvesting for thelast two decades.

Recent government investments to promote rainwater harvesting.

A lack of technical evaluations of RWH has prevented theseinvestments to be properly scrutinized

Many RWH structures are built without a clear understanding of their hydrologicimpact


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Research Objectives

Research Objectives:1. To contextualize the rainwater harvesting efforts in the

larger hydrologic context2. To quantify the amount of artificial recharge added to

groundwater supplies

3. To determine the impact of artificial recharge on thequality of groundwater.

Research Goal: to assess the

effectiveness of rainwaterharvesting for the artificialrecharge of groundwater in the

Wakal River Basin, India


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Research Objectives

Research Objectives:1. To contextualize the rainwater harvesting efforts in the

larger hydrologic context2. To quantify the amount of artificial recharge added

to groundwater supplies

3. To determine the impact of artificial recharge onthe quality of groundwater.

Research Goal: to assess the

effectiveness of rainwaterharvesting for the artificialrecharge of groundwater in the

Wakal River Basin, India

St d Sit


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UPPER PortionLOWER Portion

Study Sites

Nadi:medium-large earthen damAnicut:small-medium masonry dam

St d Sit


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Study Sites

Anicut Anicut


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Methods

Field Methods:

Groundwater tracers Groundwater level measurements

Groundwater quality measurements

Reservoir Mapping

Analytical Methods:

GIS analysis tools

Geochemical mixing models


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Results & Discussion

Impact of Artificial Recharge on Groundwater Supplies


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Artificial Recharge Lower Portion Upper Portion

Depth (mm) 94 107

Area of Influence (m2) 50,000 250,000

Volume (m3) 4,682 26,659


How much artificial recharge is added to groundwater?



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Artificial Recharge Lower Portion Upper Portion

Depth (mm) 45 44

Area of Influence (m2

) 37,600 44,300Volume (m3) 1,701 1,958




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StudySite

RWHStructure

Area ofInfluence

(m2)

2006 Rateof ArtificialRecharge(mm/yr)

Jharapipla JP.Dam 250,000 107

50,000

44,300

37,600

Jharapipla LY.ANI 94

Godawara GD.ANI 44

Godawara GD.ANI(2) 45


ArtificialRecharge

(m3)

4,682

1,958

1,701

Implication: the amount of artificial recharge can varysignificantly between similar anicutslocated a mere 10 kmapart

Artificial Recharge in Context of Rural Water Supply


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Artificial Recharge in Context of Rural Water Supply

Study SitePortionof Site

ArtificialRecharge

within Areaof Influence

(TCM)

ApproximateTotal Annual

Withdrawal withinthe Study Area

(TCM)

Upper Portion(JP.Dam)

26.7 60.1

Lower Portion(LY.ANI)

4.7 43.7

Upper Portion(GD.ANI)

2.0 15.0

Lower Portion(GD.ANI(2))

1.7 15.2Godawara

Jharapipla

*TCM = thousand cubic meters

Artificial recharge vs. withdrawal

Larger Nadiaugments 44% of 2006groundwater withdrawal

Smaller Anicutsaugment between 11-13% of 2006 groundwater withdrawal

11.2%15.21.7Lower Portion(GD.ANI(2))

13.0%15.02.0Upper Portion(GD.ANI)

Godawara

10.7%43.74.7Lower Portion(LY.ANI)

44.3%60.126.7Upper Portion(JP.Dam)

Jharapipla

Artificial Rechargeto Groundwater

Withdrawal Ratio

ApproximateTotal Annual

Withdrawal withinthe Study Area

(TCM)

ArtificialRecharge

within Areaof Influence

(TCM)

Portionof Site

Study Site

Implication: artificialrecharge compensates a

significant portion ofannual groundwaterwithdrawal

Impact of Artificial Recharge on Groundwater Quality


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Chloride(mg/l)

Sulfate(mg/l)

Fluoride(mg/l)

ElectricalConductivity

(S/cm)

Alkalinity(CaCO3)

(mg/l)

TotalHardness(CaCO3)

(mg/l)

CalciumHardness(CaCO3)

(mg/l)

MagnesiumHardness(CaCO3)

(mg/l)

TotalDissolved

Solids(mg/l)

Turbidity(NTU)

ReceivesArtificialRecharge

Mean 82.8 37.0 0.3 800.0 244.3 185.0 128.0 57.0 455.0 1.3

(JP.DW3,LY.DW1)

S.E. 6.1 11.0 0.1 27.5 7.9 9.0 5.9 4.4 29.9 0.2

NoArtificialRecharge

Mean 102.7 55.3 0.8 866.8 236.2 251.3 158.7 92.7 466.7 5.3

(JP.UW1,GD.UW2,GD.DW2)

S.E. 21.1 14.0 0.3 86.9 30.9 28.1 16.0 12.9 39.2 0.8

How does artificial recharge effect groundwater quality?



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p g Q y

Chloride(mg/l)

Sulfate(mg/l)

ElectricalConductivity

(S/cm)

Receive Artificial Recharge Mean 96.6 6.0 827

JP.DW2, JP.DW3, LY.DW0,

LY.DW1, LY.DW2, LY.DW3,GD.DW0, GD.DW3,GD.DW4 S.E. 10.8 0.5 32

No Artificial Recharge Mean 109.1 11.8 939

JP.UW1, JP.DW5, JP.DW4,GD.UW2, GD.DW2,GD.DW6 S.E. 10.8 1.0 28

The water quality pattern is maintained forthe larger data set.

An ANOVA on this data reveal that thereis a significant difference (p


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Conclusions

Groundwater supply: Artificial recharge compensates a significant

portion (11-44%) of annual groundwaterwithdrawal

The amount of artificial recharge can varysignificantly between similar anicutslocated amere 10 km apart

Groundwater quality: Artificial recharge improves groundwaterquality through the dilution of many chemical

constituents


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QUESTIONS?

rainwater harvesting - global water for sustainability

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