Metropolitan Waterworks Authority

Bangkok Water Supply Improvement Projects

Project Management Department

July 3, 2006

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Table of contents

Page

1. Introduction 1

2. Water Supply Remedial Plan 5

3. Permanent plan for Water Supply 7

4. Project Implementation and Management 15

5. Conclusion 20

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Introduction

Bangkok has been the capital of Thailand since the year 1782. From its

precapital days as a quiet village, it has grown to be one of the world’ s major

metropolitan areas. Like most such cities the construction of adequate water supply

facilities has not kept pace with the demands made by the rapidly increasing

population and made by the industrial and business growth.

Before the establishing of the Metropolitan Waterworks Authority (MWA) the

four municipals, Bangkok, Thonburi, Nontaburi and Samut Prakarn took own

responsibility in supplying portable water for people inhabited in their provinces with

the total population of approximately 3,000,000 and the responsible area of 3,192

square kilometers. At that time, only about 1.8 million people or 60% of population

benefited from individual water connections. The sources of supply came from Sam

Sen Water Treatment Plants in Bangkok with the production capacity of 550,000

CMD. Thonburi Water Treatment Plants in Thonburi province (now becomes a part

of Bangkok) with the production capacity of 170,000 CMD and many deep wells in

the four areas with total capacity of 150,000 CMD. Only about 50% of the amount of

water produced were accounted caused by water transmission and distribution

system leakages, illegal connections, public stanposts and ineffective metering etc.

The four municipalities formed the core of the Bangkok metropolitan area and

MWA assumed responsibility for supplying water to customers in 1967. Water

problems had been experienced in the metropolitan area more or less continuously

for many years. The degree of such problems, varied from year to year depending

upon the rainfall, the amount of additional water supply facilities provided and the

amount of new water demand made upon the system. In addition, complete lack of

water for hours or even days were experienced in some portions of the system which

were remote from the treatment plants or from deep wells. Without water supply

improvement project, the problems will never be solved since the annual butget

allowance or subsidy from the government was not sufficient for constructing

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adequated facilities to cope with the increasing of demand. Hence, the situation would

be more and more critical.

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Water Supply Remedial Plan

This short term plan had the objective to remedy the water supply shortage

situation only. The primary method used in the past many years to combat the water

shortage was to drill the deep wells in the general vicinity of the area with great

need. MWA kept on following this method using the annual budget made from his

own income and the government subsidized for the deficit amount of capital

expenditures. MWA also installed more trunk-mains and distribution pipelines in

continuing annual program and did the maintenance and reparation work for

existing facilities. But, with budgetary limitation, not much quantity of these facilities

could be increased each year. When the time passed by, instead at improving the

situation, it was found that it became worse and worse. Many complaint messages

or telephone calls regarding to the lack of water supply were sent to MWA every

day.

To supply the population with ground water, it was discovered that there

were both advantages and weak points, these were:

Advantages: 1. The construction of each deep wells costed not much, MWA could afford

some each year.

2. It required short period to complete the construction work, MWA could

supply water to the trouble people faster than other methods.

3. Generally, ground water contains no microorganism except when it

exposes into the air.

Disadvantages: 1. The water level drawn down and it increased the saline content to ground

water.

2. Usually, the ground water contains no dissolved oxygen, the heavy metal

like iron and Manganese could be found in many areas.

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3. Large scale withdrawal of ground water by public and private wells

appeared to exceed the water recharge capability and caused the land

subsidence in many parts of the responsible area.

For the above reasons. MWA intended to gradually discontinue the use of

ground water as source of public supply and by the year 2000 all

MWA’ s deep wells were abandoned.

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Permanent plan for Water Supply

MWA realized that the ground water could not be used for supplying the

population in the responsible area sufficiently and permanently. The only way to

solve such problems for long term was to serve them with surface water but this

would take time for the Master Plan to be accomplished and the First Stage Water

Improvement Project could be implemented.

Prior to establishing of MWA, the government had recruited Camp Dresser

and Mckee Inc. from Boston to study and prepare the Master Plan for Water Supply

Improvement Project. By that time, not various records were available for the

Consultants to study. They conducted numerous field investigation, collected and

analyses information form a wide variety of sources and finally the Master Plan was

completed in 1970. The purpose of the Master Plan was to present the estimated of

population, rate of water consumption and water demand up to the design year

2000, to recommend the water treatment process, the water treatment and

distribution facilities necessary to satisfy the expected requirements. The proposed

major improvements and extension should result in a water supply system capable

of satisfying the need of the people.

MWA learned that they need to continue using the Chao Phay river as the

principal source of water supply and it was expected that the Royal Irrigation

Department could regulate the flow in the river to insure an adequate amount for

water supply required in the design year.

The proposed surface raw water facilities include a new intake pump station

at Sam Lae, improvements to 21 kilometers of the existing raw water canal (Klong

Prapa) to conduct the river water to the treatment plant site and a new siphon

structure to allow the flow in the raw water canal to pass under Klong Rangsit which

is a major irrigation drainage canal so that the raw water for water supply will not

mixed with water from natural canal.

A large scale of water treatment plant with the total capacity of 4.8 million

cubic meter per day in the design year 2000 was recommended to be constructed

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as close as possible to Klong Prapa (raw water canal) and as close as possible to

the center of demand in order to minimize the cost of water transmission facilities.

This should be divided into 4 construction stage with the capacity 1.2 million cubic

meter per day each and the first stage program for most of the major facilities

should be completed by about 1975 and should have adequate capacity to serve

until about 1980. As a general rule, it is proposed to construct major facilities ie

water treatment plant, pumping stations and equipment so that they will have

adequate capacity for about five years after their completion. Before the end of this

five years period, a second group of facilities should be completed which also will

have sufficient capacity to serve short term future need.

In fact, to have two or three smaller water treatment plants should have more

reliability than one large scale water treatment plant because if there is unexpected

incident happen to either one of the plants, the others can still be in operation. But if

we consider in term of economic, one large scale water treatment plant should be

more economical than to have two or three smaller ones.

For water transmission system, MWA was recommended to construct a

transmission pump station at Bangkhen. The treated water from the clear water

tanks would be pumped into a transmission system of large diameter conduits. The

conduits were expected to be constructed mostly as tunnels because of their large

diameter and the fact that most of them must be constructed in congested area.

These conduits will deliver the treated water to the reservoirs of distribution pump

stations at various centers of demand.

It was proposed that at least 12 distribution pump stations would be

constructed up to the design year 2000. From there, the water will be pumped into

the distribution piping system.

The major facilities shall be constructed in increments or stages as required.

High interests rates and competing uses for the financial resources of Thailand

make it unwise to construct facilities much larger than required for the immediate

needs.

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Besides the said major facilities, MWA was also needed to install many

thousands kilometers of trunk mains and distribution pipelines to transmit water

from pump stations to customers. These kind of facilities including the service pipe

could be constructed in continuing annual program.

Moreover, the maintenance and reparation of existing facilities will be

continued annually.

To have all the aforesaid facilities constructed, it was of course, required a

massive amount of capital for investment. The cost estimation and several possible

financing method must be studied in order to form the project proposed to the

cabinet for approval.

To serve the population in the metropolitan area with surface water, the first

thing to think about or regard to is the raw water resource(s) . It does not mater

whether it will be the lake, the reservoir, river, stream or spring water, the significant

factor is that it shall be reliable in term of quantity and quality. Luckily, there is the

Chao Phya river passes through the responsible area. The catchment areas are in

the Northern part of Thailand and the tributaries, Ping, Wang, Yom, Nan, combine

together at Paknam Pho and becomes the Chao Phaya river. However, the water

storages at Phumipol and Sirikit Dams has some limitation of capacity. They could

store altogether less than 30% of the amount of rainfall in the catchment area each

year. The main purpose in utilizing water from these sources is heavily for irrigation

(Aggriculture), power, and navigation but there still be some excessive amout of

water for water supply. Though the Chao Phya river is so huge, there still be some

limitation in abstracting water in dry season because Bangkok is flat and low land

compare to the mean sea level. It happens that there is salinity intrusion along Chao

Phya river every year and if the water is withdrawn more than 45 cms. in dry

season, it is possible that the saline water will reach Sam Lae water intake and

causes a serious problem because the water treatment plants are not designed to

treat this saline water at all. Therefore it is obvious that regulation of flow from the

dams will be necessary for water supply.

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Project Implementation and Management

Since each stage of Bangkok Water Supply Project required great amount of

capital for investment, MWA had to reduce the project scale by dividing the scope of

work of each stage into phases provided that all facilities to be constructed each

phase must be completed as a whole water supply system covering water

production, water transmission and water distribution facilities. The plots of land

acquired and the facilities shall be designed with regarding to future extension.

To have the project implemented, MWA had to make plan and managed for

all relevant matter such as sources of fund, engineering consultants for detailed

design and construction supervision, project staff, project organization, coordination

from concerned government agencies ie. Bangkok Metropolitan Administration,

Highway Department, Royal Irrigation Department, Budget Bureau etc. MWA had to

reorganized not only in the engineering departments but also in the operation and

maintenance side, accounting and finance departments and other related working

units.

The First Bangkok Water Supply Improvement Project had been

implemented during the years 1974-1979 financed by two international lending

agencies, I.B.R.D., and A.D.B., MWA’ s own incomes and the government subsidy.

MWA keep on carrying out the continuing projects phase by phase in accordance

with the Master Plan. Though the completion of the project always behind the work

schedules due to various factors such as financial constraints, heavy traffic along

the construction sites etc., the water shortage situation still improved obviously. The

new Master Plan was accomplished in 1990 prepared by a group of many Thai and

a foreign engineering consulting companies and it recommended MWA to construct

another water treatment plant on the west bank of Chao Praya River called

Mahasawat Water Treatment Plant, using raw water from Maeklong River about

106 kilometers away from Bangkok for more reliability regarding the treatment

plants and raw water resources. The total capacity up to design year in 2017 is 3.2

million cubic meter per day. At present the construction of the first three phases of

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1.2 million CMD total production capacity were completed and the plants are on

operation. Up to date, the Sixth Bangkok Water Supply Improvement Project is 96%

completed and the Seventh Project has been done more than 70% progressively.

Details cost of each project are as shown in the attached table.

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Bangkok Water Supply Improvement Projects

Expected

Area

Served

Population

Served

Construct

ion

Period

Project

Cost

(Sq.Km) (Mils.) Projects

(Mil.

Baht) % %

1967 240 7.5 1.8 60

First Bangkok Water Supply

Improvement

1974 -

1979 4672.9 290 9.1 2.8 46.6

Second Bangkok Water

Supply Improvement

1980 -

1986 5489.6 475 14.9 3.6 54.3

Third Bangkok Water Supply

Improvement

1985 -

1992 9846.1 740 23.2 5.4 75.7

Fourth Bangkok Water Supply

Improvement

1991 -

2000 6706.5 1240 38.8 6.3 84.2

Fifth Bangkok Water Supply

Improvement

1992 -

2002 6972 1450 45.4 6.7 86.3

Network System Improvement

1994 -

2003 4690.1 - - - -

West Bank Raw Water Canal

1994 -

2002 5611.7 - - - -

Sixth Bangkok Water Supply

Improvement

1995 -

2003 10113 1480 46.4 6.9 86.9

Seventh Bangkok Water

Supply Improvement

1999 -

2006 25177.3 1855 58.1 7.5 89.9

Eight Bangkok Water Supply

Improvement

2007 -

2012 7800.0 2035 63.7 8.3 95.5

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Conclusion

After the economic recession in 1997, the existing supply capacity has become

slightly over the demand. In now a day MWA is able to serve portable water to

customer more than 7.5 million inhabitants which is about 91% of the population in

responsible area covering the served area of 1885 square kilometers which is about

59% of responsible area. Considering that more than 32% of the responsible area still

be farmland requiring water from river, canals or deep wells, we may say that MWA

had relieved from critical water shortage situation nearly completely. Most of the people

that has not yet been served live in the scatter and remote area from present piping

networks, however, MWA shall continue implementing the projects in order to extend

the water service to those areas.

At present, the plan for Eighth Bangkok Water Supply Project has been

approved by the Board of Director and forwarded to the Ministry of Interior and the

National Economic and Social Development Board (NESDB) for review and

concurrence. Under this plan, it is expected that all people in the whole responsible

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area would be served with portable water supply sufficiently from the year 2011 to

2017.

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Water Distribution Plan Branch 1,000 CMD.

Office 2002 2003 2004 2005 2006 2007

Sukhumvit 242 252 270 282 292 300

Prakanong 207 221 245 256 269 282

Samut Prakarn 172 194 218 251 271 292

Mansri 235 237 237 241 242 243

Phayatai 208 217 230 237 242 248

Thoongmahamek 167 169 177 183 187 190

Ladprao 180 192 212 225 235 247

Nontaburi 280 282 155 156 158 160

Bangbuathong - - 114 129 140 157

Prachachuen 135 139 142 149 154 158

Bangkhen 123 130 134 143 151 157

Minburi 69 74 96 107 120 132

Bangkoknoi 140 143 148 152 157 161

Taksin 320 335 352 367 380 391

Pasicharoen 182 195 210 222 232 242

Total 2,660 2,780 2,940 3,100 3,230 3,360

Water Loss 35.6 33.1 30.1 30.5 30.0 30.0

Water

Transmission 4.13 4.15 4.20 4.46 4.62 4.80

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Commerce, Government

Agency, Residence

State Enterprise, Industry and

others

Water Tariffs Water Tariffs Volume

(cu.m.) (Baht/cu.m.)

Volume

(cu.m.) (Baht/cu.m.)

0-30 8.50 0-10 9.50

(Not less than 45.00

Baht)

(Not less than

90.00 Baht)

31-40 10.30 11-20 10.70

41-50 10.35 21-30 10.95

51-60 10.68 31-40 13.21

61-70 11.00 51-60 13.54

71-80 11.33 61-80 13.86

81-90 12.50 81-100 14.19

91-100 12.82 101-120 14.51

101-120 13.15 121-160 15.16

121-160 13.47 161-200 15.49

161-200 13.80 Over 200 15.81

Over 200 14.45

Water TARIFFS

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Major Problems for Project Implementation

1. Low cash liquidity sometimes due to low water tariff rate.

2. Limitation of Raw Water Resources.

3. Difficulty from Land Acquisition process and unavailable plot of land for

construction.

4. Unavailable space for installation of pipelines under the road surface in

congestion area.

5. Much time required for obtaining permission to lay pipes in public and

private property.

6. Change of construction method for the installation of trunk mains from

open cut to pipe jacking method causes higher cost to the project.

7. Limitation of construction time in Bangkok each day (10.00 p.m. to 5.00

a.m.)

8. High rate for liquidated damage related to traffic control affects cost of

pipelines installation contracts.