Groundwater Management in Asian Coastal Cities: A …...Asian Science and Technology Seminar (ASTS) in Thailand March 11, 2008, Swisshotel Nai Lert Park, Bangkok Dr. Mukand S. Babel

Asian Science and Technology Seminar (ASTS) in ThailandMarch 11, 2008, Swisshotel Nai Lert Park, Bangkok

Dr. Mukand S. BabelWater Engineering and Management, AIT

Groundwater Management in Asian Coastal Cities: A proposal for climate change impact

and adaptation study

Mukand S. BabelAIT. March 2008

Presentation Outline

IntroductionCoastal aquifer issues

Research studies at AITOther studies in Asia

Potential impacts of climate change on coastal aquifersProposed researchNext steps


IntroductionGlobally, groundwater provides

about 50% of current potable water supplies (serving nearly 2 billion people)40% of self-supplied industries20% of water use in irrigation

Asia and the Pacific: groundwater provides drinking water to nearly 32% of population Coastal aquifers: important source of water in coastal zones

Indian coast (7,000km): 2nd richest GW reservoirCoastal water supplies dependent on interaction between fresh and saltwater


IntroductionUrbanization, increase in population and water demand due to economic development put immense pressure on groundwater resources leading to undesirable consequencesGroundwater use trends in Asia

Philippines: industrial and domestic use increase annually by 14% and 11.5%, resp. (1988-2001)HCMC, Vietnam: GW use steadily increases, 34% of total demand (2005)Tianjin, China: exploitation (1991-2002) has exceeded available in most districts


Introduction

Asian Cities(selected)

Role of Groundwater

Groundwater Problems

Dhaka, Bangladesh Sole source Falling groundwater levels

Tianjin, China Major source Land subsidence

Nagpur, India Major source Pollution from urban area

Jakarta, Indonesia Minor source Salinity intrusion

Cebu City, Philippines

Major source Sal. Intrusion, Pollution (urban)

Jaffna, Sri Lanka Sole source Sal. Intrusion, Pollution (urban)

Bangkok, Thailand Major source Sal. Int., Poll. (urb), subsidence

Hat Yai, Thailand Minor source Sal. Intrusion, Pollution (urban)

Hanoi, Vietnam Major source Pollution from urban areaSource: World Bank (1998). Groundwater in urban development.


Coastal Aquifer Issues

Major groundwater management issues in coastal aquifers

Decline of piezometric levelLand subsidenceGroundwater contamination (more especially salinity intrusion)


AIT Research in Bangkok AquiferPast studies (selected)

1978-1981: Investigation of Land Subsidence1978-1982: Groundwater Resources Development and Management Study1987-1992: Simulation Study of the Bangkok Aquifer System

Most recent studies (selected)2004-2007: Sustainable Groundwater Management in Bangkok (IGES) 2006-2007: Estimation of Safe Yield for the Bangkok Aquifer System

Current studies2007-2008: Groundwater Quality Management Policy Research in Bangkok and Vicinity (IGES)


AIT Research in Bangkok Aquifer

10,300 km2 total area10.6 million people (2003)



8 aquifer layersMost of extraction from 3 aquifers at depths 100-250 m (PD, NL, and NB Aquifers)Nonthaburi (NB) Aquifer: one of the most productive, yielding up to 200 m3/hr of excellent quality water Deeper aquifers seldom used by domestic wells550-m zonePN8 Pak Nam Aquifer

450-m zoneTB7 Thonburi Aquifer

350-m zonePT6 Phaya Thai Aquifer300-m zoneSK5 Sam Khok Aquifer

200-m zoneNB4 Nonthaburi Aquifer150-m zoneNL3 Nakhon Luang Aquifer

100-m zonePD2 Phra Pradaeng Aquifer50-m zoneBK1 Bangkok Aquifer

ZoneCodeAquifer

550-m zonePN8 Pak Nam Aquifer450-m zoneTB7 Thonburi Aquifer

350-m zonePT6 Phaya Thai Aquifer300-m zoneSK5 Sam Khok Aquifer

200-m zoneNB4 Nonthaburi Aquifer150-m zoneNL3 Nakhon Luang Aquifer

100-m zonePD2 Phra Pradaeng Aquifer50-m zoneBK1 Bangkok Aquifer

ZoneCodeAquifer



Groundwater Pumpage in Bangkok and Surrounding Areas

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002Year

Pum

page

(m3 /d

)

Total PumpageMWA Pumpage (Various Studies) MWA Pumpage (collected from MWA in 2004)MWA Pumpage (DMR, 1998)Estimated Private Pumpage (Various Studies)Estimated Private Pumpage (DMR, 1998)Estimated Private Pumpage (Kasetsart Univ., 2004)Estimated Public Pumpage (Kasetsart Univ., 2004)Total Pumpage (Kasetsart Univ., 2004)

Mid-1950’s: extensive use of GW startedContinuous increase in GW use until 1997According to DGR, in 2004:

Total GW use = 2.2 MCM/dPrivate Pumpage = 1.8 MCM/d

Private Users: largest groundwater users



Decline of piezometric levelPhra Pradaeng Aquifer

0

5

10

15

20

25

30

35

Apr-78 Jan-81 Oct-83 Jul-86 Apr-89 Dec-91 Sep-94 Jun-97 Mar-00 Dec-02

Wat

er L

evel

(m b

elow

G.L

.)

PD0055 Bang Bauthong, NonthaburiPD0002 Muang, Samut PrakanPD0040 Minburi, BangkokPD0068 Bang Sai, AyutthayaPD0059 Lat Lumkaew, Pathm ThaniPD0053 Nakhon Chaisiri, Nakhon PathomPD0018 Kra Thumbaen, Samut Sakhon



Decline of piezometric levelNakhon Luang Aquifer

0

10

20

30

40

50

60

70

80


Wat

er L

evel

(m b

elow

G.L

.)

NL0005 Bang Bauthong, NonthaburiNL0055 Muang, Samut PrakanNL0016 Minburi, BangkokNL0012 Bang Sai, AyutthayaNL0071 Lat Lumkaew, Pathum ThaniNL0068 Nakhon Chaisiri, Nakhon PathomNL0032 Kra Thumbaen, Samut Sakhon



Decline of piezometric levelNonthaburi Aquifer

0

10

20

30

40

50

60

70

80


Wat

er L

evel

(m b

elow

G.L

.)

NB0004 Bang Bauthong, NonthaburiNB0049 Muang, Samut PrakanNB0046 Minburi, BangkokNB0069 Bang Sai, AyutthayaNB0015 Lat Lumkaew, Pathum ThaniNB0020 Nakhon Chaisiri, Nakhon PathomNB0025 Kra Thumbaen, Samut Sakhon Samut Sakhon

Bangkok



Land subsidence Land subsidence still occurring (~1.0 cm/yr in most parts)Since 1978: Max. subsidence= ~1.0 m observed1979-1981: Reached 5-10 cm/yr in some areasSubsiding areas coincide with GW depression zonesSurrounding areas at riskLand Subsidence in 2003 (Source: DGR)



Land subsidence



Groundwater contamination

20 0 20 40 Kilometers

N

EW

S

Chloride levels (mg/L) in PD aquifer, 1990

Chloride levels (mg/L)0-250250-600600-10001000-30003000-50005000-1000010000-20000N D



N

EW

S







N

EW

S







1969: Land subsidence given public attention1978: Enforced Groundwater Act, B.E. 2520 (1977); Start licensingfor groundwater activities1983: Critical Zone identified (4 provinces)1984: Groundwater tariff of 1 Bt/m3 imposed (6 provinces)1992: Groundwater Act amended1994: Tariff increased to 3.5 Bt/m3 (6 provinces)1995: All provinces must pay groundwater charge; Critical Zone expanded (7 provinces)2000-’03: Tariff increased from 3.5 to 8.25 Bt/m3 (in Critical Zone)2003: Groundwater Act amended2004: Tariff increased to 8.5 Bt/m3 (Critical Zone); Groundwater Preservation Charge imposed in Critical Zone

Measures undertaken by the Government



THB 17.00

THB 8.50THB 8.50

THB 3.50

THB 1.00

0123456789

101112131415161718

Jan-

84

Jan-

85

Jan-

86

Jan-

87

Jan-

88

Jan-

89

Jan-

90

Jan-

91

Jan-

92

Jan-

93

Jan-

94

Jan-

95

Jan-

96

Jan-

97

Jan-

98

Jan-

99

Jan-

00

Jan-

01

Jan-

02

Jan-

03

Jan-

04

Jan-

05

Jan-

06

Date

Cha

rge

(Bt/

m3 )

Total Groundwater Charge

Groundwater Preservation Charge

Groundwater Use Charge TOTAL CHARGE



1. Lack of institutional thrust (Resulting in ineffective laws and regulations)

Illegal wells still exist; Not all wells metered despite regulations2. Inadequate inspection and budgetary constraints3. Groundwater Database and Monitoring System not updated

and maintainedMonitoring well system does not cover all aquifers

4. Lack of alternative sources of waterLimits control of groundwater use and effectiveness of charges

5. Groundwater Development FundDifficult to use Fund by other stakeholders especially by academic institutions, and even by DGR

6. Groundwater Preservation ChargeImposed at a flat rate

Major Deficiencies Identified (2004-07 study)



Regulatory or Direct ControlControlling illegal users of groundwaterControlling the use of water in industriesRelocation of large groundwater users (ex. Industries)Allow some authority (existing or new) to extract groundwater and supply to customers

Economic MeasuresAlso charge agro-wells for groundwater useModification of Groundwater Preservation Charge ratesFurther increase of groundwater use charges

Proposed Policy Options/Improvements (2004-07 study)



Technical MeasuresConduct artificial recharge (ASR)Provision of alternative water sources

Supporting MeasuresUpdating/redefining the Critical ZonesImproved monitoring of groundwater activitiesDemand-side management in domestic and industrial sectors, such as leakage management in pipe networksAmendment of the Groundwater Act or relevant regulations regarding the procedural changes in the use of the Groundwater DevelopmentFund (GDF)Promote the sustainable use of groundwater instead of complete stoppage as well as the conjunctive use of groundwater and surface waterPromotion of knowledge and public awareness on groundwaterEstablish regulations at national and local levelsBuild local capacities in managing groundwater

Proposed Policy Options / Improvements



Objectives of the current study on GW quality (2007-2008)

Collect background data and assess the extent of groundwater pollution (more particularly chloride contamination) in Bangkok aquifer system focusing on the three aquifers: PD, NL, NB;Collect and analyze the existing policies on groundwater quality management to determine their effectiveness and identifying gaps with respect to the current situation;Suggest options and/or policy measures to address the flaws in existing groundwater quality management


Other Studies in Asia

Decline of piezometric levelManila, Philippines: groundwater abstraction has lowered the piezometric level by 2.4m per year HCMC, Vietnam: groundwater table declines down to 1.95m annually (1994-2003)Tianjin, China: water level has continually dropped in saltwater regions

Source: Agenda for Water Sector Strategy for North China. Ministry of Water Resources,

World Bank and AUSAID, 2001

Difference between deep groundwater levels in 1958 and 1998 in the Hai Basin Plains in northern China


Other Studies in Asia

Land subsidenceMetro Manila, Philippines: subsidence ranges from 0.12 to 1.20 cmTianjin, China: 7,300 km2 is affected, max subsidence at 3m (1959-1994)


Other Studies in AsiaSalinity intrusion

Andhra Pradesh, India: brackish groundwater have been observedManila, Philippines: intrusion in aquifers reaching 5km inland, upconing of saline connate water; Cl levels in some parts exceeded 17,000mg/LHCMC, Vietnam: 2,359 damaged wells due to saltwater intrusion S. Korea (west): 5% of wells within 10km from coast with Chloride levels above standards


SEVERITY OF ISSUES WERE MAINLY DUE TO INCREASE IN GROUNDWATER EXTRACTION….

WHAT ABOUT THE IMPACTS OF CLIMATE CHANGE???


Climate Change Impacts1. Potential impacts by changes in

temperature and precipitationChanges in precipitation and evaporation will influence recharge, including temporal changes Increased evapotranspiration in semi-arid and arid regions may lead to salinization of shallow aquifersDroughts result to declining water levels,while increased rainfall intensity may lead to more runoff and less rechargeReduced groundwater head caused by lower rainfall will exacerbate the impacts of sea level rise


Climate Change Impacts

1. Potential impacts by changes in temperature and precipitation

Coastal aquifers in Peninsular India is expected to lose 0.075-0.078% of fresh groundwater per year from 2000-2099 due to increased salinityIncreased extraction of groundwater (more particularly in deep aquifers) as surface water becomes more unreliable

BUT, overexploitation of the deep aquifers will cause arsenic contamination in deep aquifers, e.g. in western Bangladesh


Climate Change Impacts2. Potential impacts due to sea level rise

(globally, 2 to 3 mm/yr in the early 21st century)Sea level rise leads to intrusion of saltwater into fresh groundwater in coastal aquifers (India, China and Bangladesh are especially susceptible)In two small, flat coral islands off the coast of India, the thickness of freshwater lens was computed to decrease from 25m to 10m and from 36m to 28m for a sea level rise of only 0.1mIn Ho Chi Minh City, saltwater intrusion has been observed and is escalatingTidal inflow into the Pasig River (Philippines) contributes to high salinity of groundwater


Climate Change ImpactsAdaptation issues

Increasing knowledge and awareness of vulnerability of coastal aquifers to climate changeIncreasing storage capacity: groundwater recharge, rainwater harvesting and conservationEnabling environment for groundwater governance – more inclusive management of groundwater resourcesCapacity of institutions and suitability of institutional arrangements to cope with the impacts of climate change capacity buildingFinancial resources to support adaptation measures


WHAT HAS BEEN DONE???

At present, there has been only very littleresearch on the impact of climate change on groundwater resources


OUR PROPOSAL….


Proposed Research

Assessing the impacts of climate change on coastal aquifers

Groundwater quantity Groundwater quality

Recommendation of policy options/measures based on technical findings for adaptation


Proposed Research

Groundwater quantityGroundwater qualityNatural ecosystemsSociety and economyEtc.

Assessing the impacts of climate change on coastal aquifers (some ideas)


Proposed Research

Identification of recharge areas of deep aquifersEffects of changes in precipitation, temperature and land use on recharge amount in these areasEstimation of safe yieldIdentification of appropriate measures for sustainability of deep aquifers in coastal areas

Groundwater Quantity (some ideas)


Proposed Research

Understanding the mechanism of salinity intrusion in coastal aquifersAssessment of sea level rise in selected coastal areasCharacterization of salinity intrusion in selected coastal aquifers in Asia under climate change scenarios

Groundwater Quality (some ideas)


Proposed Research

Adaptive measures grouped according to the following categories

Regulatory or Direct Control MeasuresEconomic MeasuresTechnical MeasuresInformative MeasuresSupporting Measures

Recommendation of policy options/measures for adaptation (some ideas)


Next Steps

Development of research partnershipDevelopment of concept paper and full proposalto be initiated by AIT (with inputs from this forum)Funding by donor agencies??Research implementation (3-5 years)

Thank you

Documents

Groundwater Management in Asian Coastal Cities: A …...Asian Science and Technology Seminar (ASTS) in Thailand March 11, 2008, Swisshotel Nai Lert Park, Bangkok Dr. Mukand S. Babel