overview of water supply in asian cities

Overview of Water Supply in

Asian Cities

Exploring Water City Planning for Bangkok

Final Workshop: Extending Urban Metabolism

Novotel Siam Square, Bangkok Thailand

13 November 2014

Dr. Vitor Vieira Vasconcelos

CNPq scholarship (Brazil)

Stockholm Environment Institute

Developed with the support of CNPq – National Council for

Technological and Scientific Development – Brazil.

Contents

• Challenges faced by Asian cities

• Constraints on choices for water supply

• Comparison of water sources and losses for 10

cities in Asia

• General trends of water supply

– How Bangkok fits into these patterns

• Open questions on strategies for water

management

Challenges of Asian Megacities

• Urban Growth

– Increasing demand

– Pollution of existing resources

• Private or non-formal water extraction

• Limited budget or revenue capacity

Water Quantity Constraints

• Surface water

– Rivers and Reservoirs capacity

– Is there a water supply

structure available?

• Groundwater

– Aquifer depletion

– Subsidence

Which option

to use?

Water Quality Constraints

• Surface water

– Sewage

• Groundwater

– Aquifer geochemistry

– Saltwater intrusion

– Leakage from surface water

• Rivers and canals

• Flood

Which option

to use?

A Comparison on Water Sources

• Each city has a different natural potential

• Each city has as a different societal history

• What is similar? What is different?

• Can we learn with the history of each other?

Water Sources

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok

Surface Water Groundwater

Rain Harvest Reclamation Water

Desalinization

IGES - Institute for

Global Environmental

(2007). Sustainable

Groundwater

Management in Asian

Cities. Japan. 179p.

Haq, KA (2006) Water Management in Dhaka.

Water Resources Development 22(2): 291–311.

Singapore National Water Agency. (2013). Our

Water, Our Future. http://www.pub.gov.sg/

Grönwall, JT, et al. (2010) Groundwater, self-

supply and poor urban dwellers: A review with

case studies of Bangalore and Lusaka (26). IIED

Taniguchi, M 2011,03 “Groundwater and

Subsurface Environments – Human Impacts in

Asian Coastal Cities – “. Springer, 312pp

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok

Surface Water GroundwaterRain Harvest Reclamation WaterDesalinization

Water Sources

Large

infrastructure

for surface

water supply

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok


Water Sources

Large deltas,

but unequal

infrastructure for

surface water

supply

Water Sources

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok


Plateaus -

limited surface

and groundwater

sources

Water Sources

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok


Small basins,

relying on

inter-basin

transfer

Water Sources

Coastal cities:

risk of

saltwater

intrusion

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok


0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok


Water Sources

Coastal cities:

risk of salt

intrusion

Deltas

0% 20% 40% 60% 80% 100%

Singapore

Bangalore

Manila

Dhaka

Kandy

Colombo

Tianjin

Ho Chi Minh

Bandung

Bangkok


Water Losses

• Pressure X Losses

• Pipes age

• Subsidence

• Reforms:

– Management focus

– Capital

Efficiency changing along time

Wa

ter

Loss

es

(%)

0

10

20

30

40

50

60

70

19

93

19

95

19

97

19

99

20

01

20

03

20

05

20

07

20

09

20

11

20

13

Manila (east)

Dhaka

Colombo

Bandung

Bangalore

Bangkok

Ho Chi Minh

Kandy

Singapore

Source: WMA and many reference databases

What could we learn?• The private or public choice for surface or groundwater

depends on constraints of quantity and quality

• Developing surface water supply is an essential policy to deal with groundwater over-abstraction

• Coastal, deltaic and plateau cities face different challenges on constraints to surface and groundwater use

• Dealing with water loss is a challenging but rewarding measure

Typical evolution of water supply sources in large cities (surrounded by high-yielding aquifers)

Foster, S., Vairavamoorthy, K. (2013). GWP- Urban Groundwater: Policies and Institutions for Integrated Management. GWP Perspectives Papers. 20p.

Water table trend in Bangkok

Source : Department of Groundwater Resources

Water table trend in Bangkok

Endo, T. Sinking Cities and Governmental Action:

Institutional Responses to Land Subsidence in

Osaka and Bangkok. In: Taniguchi, M 2011,03

“Groundwater and Subsurface Environments –

Human Impacts in Asian Coastal Cities – “.

Springer, 312pp

Mil

lio

n m

3/d

ay

1st critical zoning

(1983)

2st critical zoning

(1994)

3st critical zoning

(2000)

4.94

(2013)

1st Revision of GW Act

(1992)

2nd Revision of GW Act

(2003)

Water table trend in Samutprakarn

History of Groundwater Use

Yoshikoshi, A. Urban Development and Water Environment Changes in Asian Megacities. In: Taniguchi, M (2011) Groundwater

and Subsurface Environments: Human Impacts in Asian Coastal Cities. Springer, 312pp

Dhaka

Ho Chi Min

Household Demand

Taniguchi, M (2011) Groundwater and Subsurface Environments: Human Impacts in Asian Coastal Cities. Springer, 312pp

Pattern for

cities in

developing

countries?

50

70

90

110

130

150

170

190

Residential Water Use Per Capita in Bangkok

Water Use Per Capita

m3/y

ea

r

Source: WMA

Concluding Reflections• Policy enforcement and tariff scheme in Bangkok

were effective in returning the overall level of

water table over 15 years.

– A new zoning could evidence

• Remaining critical areas where there is still subsidence, in

Bangkok and expanded neighborhood

• If we should prepare for the risk of uplifting

• Household demand tends to stabilize

– And what is next? Could we decrease household

demand?

Knowing where we are,

and estimating the possible trends,

where should we prioritize the investments?

- Network rehabilitation?

- Enforcement on control of groundwater use?

- Development of surface water supply?

- Wastewater treatment?

Concluding Reflections

Comments? Questions?

��!

Dr. Vitor Vieira Vasconcelos

[email protected]