Presentation: S4-1

Groundwater Management in Asian Coastal
Cities: A proposal for climate change impact
and adaptation study
Asian Science and Technology Seminar (ASTS) in Thailand
March 11, 2008, Swisshotel Nai Lert Park, Bangkok
Dr. Mukand S. Babel
Water Engineering and Management, AIT
Presentation Outline
„ Introduction
„ Coastal aquifer issues
ƒ Research studies at AIT
ƒ Other studies in Asia
„ Potential impacts of climate change
on coastal aquifers
„ Proposed research
„ Next steps
Mukand S. Babel
AIT. March 2008
Introduction
„ Globally, groundwater provides
ƒ about 50% of current potable water supplies
(serving nearly 2 billion people)
ƒ 40% of self-supplied industries
ƒ 20% 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
ƒ Indian coast (7,000km): 2nd richest GW reservoir
ƒ Coastal water supplies dependent on interaction
between fresh and saltwater
Mukand S. Babel
AIT. March 2008
Introduction
„ Urbanization, increase in population and water
demand due to economic development put
immense pressure on groundwater
resources leading to undesirable
consequences
„ Groundwater use trends in Asia
ƒ Philippines: industrial and domestic use increase
annually by 14% and 11.5%, resp. (1988-2001)
ƒ HCMC, Vietnam: GW use steadily increases,
34% of total demand (2005)
ƒ Tianjin, China: exploitation (1991-2002) has
exceeded available in most districts
Mukand S. Babel
AIT. March 2008
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 area
Source: World Bank (1998). Groundwater in urban development.
Mukand S. Babel
AIT. March 2008
Coastal Aquifer Issues
„ Major groundwater management issues in
coastal aquifers
ƒ Decline of piezometric level
ƒ Land subsidence
ƒ Groundwater contamination (more especially
salinity intrusion)
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
„ Past studies (selected)
ƒ 1978-1981: Investigation of Land Subsidence
ƒ 1978-1982: Groundwater Resources Development and
Management Study
ƒ 1987-1992: Simulation Study of the Bangkok Aquifer
System
„ Most recent studies (selected)
ƒ 2004-2007: Sustainable Groundwater Management in
Bangkok (IGES)
ƒ 2006-2007: Estimation of Safe Yield for the Bangkok
Aquifer System
„ Current studies
ƒ 2007-2008: Groundwater Quality Management Policy
Research in Bangkok and Vicinity (IGES)
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
„ 10,300 km2 total area
„ 10.6 million people (2003)
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
Aquifer
Code
Zone
1 Bangkok Aquifer
BK
50-m zone
2 Phra Pradaeng Aquifer
PD
100-m zone
3 Nakhon Luang Aquifer
NL
150-m zone
4 Nonthaburi Aquifer
NB
200-m zone
5 Sam Khok Aquifer
SK
300-m zone
6 Phaya Thai Aquifer
PT
350-m zone
7 Thonburi Aquifer
TB
450-m zone
8 Pak Nam Aquifer
PN
550-m zone
„ 8 aquifer layers
„ Most of extraction from 3
aquifers at depths 100250 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 wells
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
2,500,000
Pumpage (m3/d)
2,000,000
1,500,000
Groundwater Pumpage in Bangkok and Surrounding Areas
Total Pumpage
MWA 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)
1,000,000
500,000
0
1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002
Year
„ Mid-1950’s: extensive
use of GW started
„ Continuous increase
in GW use until 1997
„ According to DGR, in
2004:
ƒ Total GW use =
2.2 MCM/d
ƒ Private Pumpage
= 1.8 MCM/d
„ Private Users: largest
groundwater users
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Decline of piezometric level
Phra Pradaeng Aquifer
Apr-78 Jan-81 Oct-83
0
Water Level (m below G.L.)
5
10
Jul-86
Apr-89 Dec-91 Sep-94 Jun-97 Mar-00 Dec-02
PD0055 Bang Bauthong, Nonthaburi
PD0002 Muang, Samut Prakan
PD0040 Minburi, Bangkok
PD0068 Bang Sai, Ayutthaya
PD0059 Lat Lumkaew, Pathm Thani
PD0053 Nakhon Chaisiri, Nakhon Pathom
PD0018 Kra Thumbaen, Samut Sakhon
15
20
25
30
35
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Decline of piezometric level
Nakhon Luang Aquifer
Apr-78 Jan-81 Oct-83
Jul-86
Apr-89 Dec-91 Sep-94 Jun-97 Mar-00 Dec-02
0
Water Level (m below G.L.)
10
20
30
40
50
60
70
80
NL0005 Bang Bauthong, Nonthaburi
NL0055 Muang, Samut Prakan
NL0016 Minburi, Bangkok
NL0012 Bang Sai, Ayutthaya
NL0071 Lat Lumkaew, Pathum Thani
NL0068 Nakhon Chaisiri, Nakhon Pathom
NL0032 Kra Thumbaen, Samut Sakhon
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Decline of piezometric level
Nonthaburi Aquifer
Apr-78 Jan-81 Oct-83
Jul-86
Apr-89 Dec-91 Sep-94 Jun-97 Mar-00 Dec-02
0
Water Level (m below G.L.)
10
20
30
40
50
60
70
80
NB0004 Bang Bauthong, Nonthaburi
NB0049 Muang, Samut Prakan
NB0046 Minburi, Bangkok
NB0069 Bang Sai, Ayutthaya
NB0015 Lat Lumkaew, Pathum Thani
NB0020 Nakhon Chaisiri, Nakhon Pathom
NB0025 Kra Thumbaen, Samut Sakhon
Bangkok
Samut Sakhon
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Land subsidence
Land Subsidence in 2003 (Source: DGR)
„ Land subsidence still
occurring (~1.0 cm/yr in
most parts)
„ Since 1978: Max.
subsidence= ~1.0 m
observed
„ 1979-1981: Reached 510 cm/yr in some areas
„ Subsiding areas
coincide with GW
depression zones
„ Surrounding areas at
risk
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Land subsidence
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Groundwater contamination
N
W
E
S
20
0
20
40 Kilometers
Chloride levels (mg/L)
0-250
250-600
600-1000
1000-3000
3000-5000
5000-10000
10000-20000
N D
Chloride levels (mg/L) in PD aquifer, 1990
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Groundwater contamination
N
W
E
S
20
0
20
40 Kilometers
Chloride levels (mg/L)
0-250
250-600
600-1000
1000-3000
3000-5000
5000-10000
10000-20000
N D
Chloride levels (mg/L) in PD aquifer, 1995
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
ƒ Groundwater contamination
N
W
E
S
20
0
20
40 Kilometers
Chloride levels (mg/L)
0-250
250-600
600-1000
1000-3000
3000-5000
5000-10000
10000-20000
N D
Chloride levels (mg/L) in PD aquifer, 2005
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
Measures undertaken by the Government
„ 1969: Land subsidence given public attention
„ 1978: Enforced Groundwater Act, B.E. 2520 (1977); Start licensing
for groundwater activities
„ 1983: Critical Zone identified (4 provinces)
„ 1984: Groundwater tariff of 1 Bt/m3 imposed (6 provinces)
„ 1992: Groundwater Act amended
„ 1994: 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 amended
„ 2004: Tariff increased to 8.5 Bt/m3 (Critical Zone); Groundwater
Preservation Charge imposed in Critical Zone
Mukand S. Babel
AIT. March 2008
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
THB 17.00
Total Groundwater Charge
Groundwater Preservation Charge
TOTAL CHARGE
Groundwater Use Charge
THB 8.50
THB 8.50
THB 3.50
Jan-06
Jan-05
Jan-04
Jan-03
Jan-02
Jan-01
Jan-00
Jan-99
Jan-98
Jan-97
Jan-96
Jan-95
Jan-94
Jan-93
Jan-92
Jan-91
Jan-90
Jan-89
Jan-88
Jan-87
Jan-86
Jan-85
THB 1.00
Jan-84
3
Charge (Bt/m )
AIT Research in Bangkok Aquifer
Date
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
Major Deficiencies Identified (2004-07 study)
1. Lack of institutional thrust (Resulting in ineffective laws and
regulations)
ƒ
Illegal wells still exist; Not all wells metered despite regulations
2. Inadequate inspection and budgetary constraints
3. Groundwater Database and Monitoring System not updated
and maintained
ƒ
Monitoring well system does not cover all aquifers
4. Lack of alternative sources of water
ƒ
Limits control of groundwater use and effectiveness of charges
5. Groundwater Development Fund
ƒ
Difficult to use Fund by other stakeholders especially by academic
institutions, and even by DGR
6. Groundwater Preservation Charge
ƒ
Imposed at a flat rate
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
Proposed Policy Options/Improvements (2004-07 study)
„ Regulatory or Direct Control
ƒ
ƒ
ƒ
ƒ
Controlling illegal users of groundwater
Controlling the use of water in industries
Relocation of large groundwater users (ex. Industries)
Allow some authority (existing or new) to extract
groundwater and supply to customers
„ Economic Measures
ƒ Also charge agro-wells for groundwater use
ƒ Modification of Groundwater Preservation Charge
rates
ƒ Further increase of groundwater use charges
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
Proposed Policy Options / Improvements
„ Technical Measures
ƒ Conduct artificial recharge (ASR)
ƒ Provision of alternative water sources
„ Supporting Measures
ƒ Updating/redefining the Critical Zones
ƒ Improved monitoring of groundwater activities
ƒ Demand-side management in domestic and industrial sectors, such as
leakage management in pipe networks
ƒ Amendment of the Groundwater Act or relevant regulations regarding
the procedural changes in the use of the Groundwater Development
Fund (GDF)
ƒ Promote the sustainable use of groundwater instead of complete
stoppage as well as the conjunctive use of groundwater and surface
water
ƒ Promotion of knowledge and public awareness on groundwater
ƒ Establish regulations at national and local levels
ƒ Build local capacities in managing groundwater
Mukand S. Babel
AIT. March 2008
AIT Research in Bangkok Aquifer
„ Objectives of the current study on GW quality
(2007-2008)
ƒ 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;
ƒ Collect and analyze the existing policies on
groundwater quality management to determine their
effectiveness and identifying gaps with respect to the
current situation;
ƒ Suggest options and/or policy measures to address
the flaws in existing groundwater quality management
Mukand S. Babel
AIT. March 2008
Other Studies in Asia
„ Decline of piezometric level
ƒ Manila, Philippines: groundwater abstraction has
lowered the piezometric level by 2.4m per year
ƒ HCMC, Vietnam: groundwater table declines
down to 1.95m annually (1994-2003)
ƒ Tianjin, China: water level has continually
dropped in saltwater regions
Difference between deep groundwater levels in 1958 and 1998 in
the Hai Basin Plains in northern China
Source: Agenda for Water Sector Strategy for
North China. Ministry of Water Resources,
World Bank and AUSAID, 2001
Mukand S. Babel
AIT. March 2008
Other Studies in Asia
„ Land subsidence
ƒ Metro Manila,
Philippines: subsidence
ranges from 0.12 to
1.20 cm
ƒ Tianjin, China: 7,300
km2 is affected, max
subsidence at 3m
(1959-1994)
Mukand S. Babel
AIT. March 2008
Other Studies in Asia
„ Salinity intrusion
ƒ Andhra Pradesh, India: brackish
groundwater have been observed
ƒ Manila, Philippines: intrusion in
aquifers reaching 5km inland,
upconing of saline connate water;
Cl levels in some parts exceeded
17,000mg/L
ƒ HCMC, Vietnam: 2,359 damaged
wells due to saltwater intrusion
ƒ S. Korea (west): 5% of wells
within 10km from coast with
Chloride levels above standards
Mukand S. Babel
AIT. March 2008
SEVERITY OF ISSUES WERE MAINLY DUE
TO INCREASE IN GROUNDWATER
EXTRACTION….
WHAT ABOUT THE IMPACTS OF
CLIMATE CHANGE???
Mukand S. Babel
AIT. March 2008
Climate Change Impacts
1. Potential impacts by changes in
temperature and precipitation
ƒ
ƒ
ƒ
ƒ
Changes in precipitation and evaporation
will influence recharge, including
temporal changes
Increased evapotranspiration in semi-arid
and arid regions may lead to salinization
of shallow aquifers
Droughts result to declining water levels,
while increased rainfall intensity may lead
to more runoff and less recharge
Reduced groundwater head caused by
lower rainfall will exacerbate the impacts
of sea level rise
Mukand S. Babel
AIT. March 2008
Climate Change Impacts
1. Potential impacts by changes in temperature
and precipitation
ƒ
ƒ
Coastal aquifers in Peninsular India is expected to
lose 0.075-0.078% of fresh groundwater per year
from 2000-2099 due to increased salinity
Increased 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
Mukand S. Babel
AIT. March 2008
Climate Change Impacts
2. Potential impacts due to sea level rise
(globally, 2 to 3 mm/yr in the early 21st century)
ƒ Sea level rise leads to intrusion of saltwater into
fresh groundwater in coastal aquifers (India, China
and Bangladesh are especially susceptible)
ƒ 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 0.1m
ƒ In Ho Chi Minh City, saltwater intrusion has been
observed and is escalating
ƒ Tidal inflow into the Pasig River
(Philippines) contributes to high
salinity of groundwater
Mukand S. Babel
AIT. March 2008
Climate Change Impacts
„ Adaptation issues
ƒ Increasing knowledge and awareness of
vulnerability of coastal aquifers to climate change
ƒ Increasing storage capacity: groundwater
recharge, rainwater harvesting and conservation
ƒ Enabling environment for groundwater
governance – more inclusive management of
groundwater resources
ƒ Capacity of institutions and suitability of
institutional arrangements to cope with the
impacts of climate change Æ capacity building
ƒ Financial resources to support adaptation
measures
Mukand S. Babel
AIT. March 2008
WHAT HAS BEEN DONE???
At present, there has been only very little
research on the impact of climate change on
groundwater resources
Mukand S. Babel
AIT. March 2008
OUR PROPOSAL….
Mukand S. Babel
AIT. March 2008
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
Mukand S. Babel
AIT. March 2008
Proposed Research
Assessing the impacts of climate change on
coastal aquifers (some ideas)
„ Groundwater quantity
„ Groundwater quality
„ Natural ecosystems
„ Society and economy
„ Etc.
Mukand S. Babel
AIT. March 2008
Proposed Research
Groundwater Quantity (some ideas)
„ Identification of recharge areas of deep aquifers
„ Effects of changes in precipitation, temperature
and land use on recharge amount in these areas
„ Estimation of safe yield
„ Identification of appropriate measures for
sustainability of deep aquifers in coastal areas
Mukand S. Babel
AIT. March 2008
Proposed Research
Groundwater Quality (some ideas)
„ Understanding the mechanism of salinity
intrusion in coastal aquifers
„ Assessment of sea level rise in selected coastal
areas
„ Characterization of salinity intrusion in selected
coastal aquifers in Asia under climate change
scenarios
Mukand S. Babel
AIT. March 2008
Proposed Research
Recommendation of policy options/measures for
adaptation (some ideas)
„ Adaptive measures grouped according to the
following categories
ƒ Regulatory or Direct Control Measures
ƒ Economic Measures
ƒ Technical Measures
ƒ Informative Measures
ƒ Supporting Measures
Mukand S. Babel
AIT. March 2008
Next Steps
„ Development of research partnership
„ Development of concept paper and full proposal
to be initiated by AIT (with inputs from this
forum)
„ Funding by donor agencies??
„ Research implementation (3-5 years)
Mukand S. Babel
AIT. March 2008
Thank you