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Water quality management of the ChaoPhraya River (a case study)Samorn Muttamara a & Candelaria L. Sales aa Environmental Engineering Program, School of Environment, Resources andDevelopment , Asian Institute of Technology , G.P.O. Box 2754, Bangkok,ThailandPublished online: 17 Dec 2008.

To cite this article: Samorn Muttamara & Candelaria L. Sales (1994) Water quality management of the ChaoPhraya River (a case study), Environmental Technology, 15:6, 501-516

To link to this article: http://dx.doi.org/10.1080/09593339409385457

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Environmental Technology, Vol. 15. pp 507-516© Publications Division Selper Ltd., 1994

WATER QUALITY MANAGEMENT OF THE CHAOPHRAYA RIVER (A CASE STUDY)

SAMORN MUTTAMARA AND CANDELARIA L. SALES

Environmental Engineering Program, School of Environment, Resources and Development,Asian Institute of Technology, G.P.O. Box 2754, Bangkok, Thailand

(Received 29 November 1993; Accepted 7 March 1994)

ABSTRACT

The Chao Phraya River is the largest river in Thailand. It is formed from the four main rivers inthe northern part of Thailand, the Ping, Wang, Yom and Nan rivers and drains an area of about178,000 sq. km. This mighty river has been exhaustively used to its full extent for hundred ofyears for consumption, industries, agriculture, fisheries, transportation and worse thananything else, as a receiving body of liquid and solid wastes from all sorts of human activities.With the continuing growth of urban population and industrial outputs, the pressure on waterquality is becoming intense in Thailand. The river water characteristics (dissolved oxygen,biochemical oxygen demand, coliform bacteria and etc.) especially in the lower part, are muchinferior to the standard values. Thus, appropriate water quality management and an urgentmitigation plan should be implemented. The implications of pollution of the Chao Phraya Riverare wide ranging and could affect various socio-economic aspects of life. Likewise, the rapidurbanization and industrialization also require a dramatic increase in water demand, leading towater shortage. This problem is attributed mainly due to lack of an efficient water managementsystem; discharge of untreated effluents from domestic and industrial activities; deforestation;lack of co-operation and co-ordination among private and government sectors concerned; noexisting laws and regulations related to water resource conservation; and non-effectiveness ofwater quality standards, regulations and penalties. To effectively minimize the wastage of waterresources and pollution in the Chao Phraya River, water conservation program should be adoptedby the Bangkok Metropolitan Region while regulations and standards should be framed up in apractical and flexible way. Besides, there should be a permanent system of incentives based onappropriate regulations and economic measures and a rational and effective pricing system.

Keywords: Water quality, water pollution, impacts, management, regulations

INTRODUCTION

Thailand, a tropical country having an areaof about 513,115 sq. km is divided into four mainregions: the mountainous north, the semi-aridplateau in the northeast, a fertile plain of thecentral region and the isthmus of the south. Thecountry has three major rivers namely: the ChaoPhraya, Thatchin and Maeklong (Figure 1) whichare originating from the mountainous northernregion.

The Chao Phraya is the largest river of thecountry which drains an area of about 178,000 sq.km and holding a volume of 30,000 million cubicmeters. Geographically, it is formed from fourmain rivers in the northern part of Thailand,viz. the Ping, Wang, Yom and Nan rivers which

meet at Nakhon Sawan. This is one of the mostimportant rivers with about 380 km from theorigin of Nakhon Sawan to the outfall at SamutPrakarn. The benefits derived from this riverare multifarious, for industries, fisheries,agriculture, t ransporta t ion, domesticconsumption, etc. wherein most of thecommunities and consumers especially inBangkok depend largely on this river. There arealso many commercial establishments whichbenefit from both sides of the river, such asrestaurants, hotels, condominiums, and piers. Inthe contrary, those people who get the most benefitfrom the river have done nothing to protect it,instead, they continue to discharge pollutants intothe river.

The continuing deterioration of water

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quality in the Chao Phraya River has become aserious environmental concern brought about bythe discharge of industrial, domestic, andagricultural wastewaters into the river. In 1990,the total BOD discharged by domestic sewage andindustrial waste was estimated to be 183,634 kg ofBOD day1 (1). It has been reported that the upperpart of the river though not much affected bypollution, has shown slight indications ofpollution at certain places. The water quality inthe middle part of the river has begun to bepolluted at a rather high rate especially at thelocation where water is abstracted for producingwater supply to the city of Bangkok. Apparently,the lower part has been indicated as highlypolluted, with dissolved oxygen levelsapproaching zero.

It is necessary therefore, to upgrade thecondition of the river and thus better ways andmeans to solve the river pollution problems mustbe worked out and an appropriate water qualitymanagement of the Chao Phraya river should beimplemented. Effective water pollution control

as well as precise and accurate water qualitysurveillance and monitoring data should becarried out.

Water Quality of Chao Phraya River

The mighty Chao Phraya River has beenexhaustively used to its full extent for hundreds ofyears for consumption, agriculture, fishery,industries, communication and worse thananything else, as a receiving body for liquid andsolid wastes from all sorts of human activities.In recent modern times, the pollution of thisriver is becoming a glaring problem due toexcessive organic waste load entering the riverhas already crossed the "Natural AssimilativeCapacity" of the river (2).

Zoning and Classification of the River

In order to mitigate the problem of waterpollution, the Ministry of Science, Technologyand Energy (3) in 1986 has set surface water

CENTRAL PLAIN

Z SOUTHEAST COAST

NORTHEAST PLATEAU

4 CENTRAL HKHLANOS

9 NORTH ANO WEST

CONTINENTAL HKHLANOS

rCNWSULAR THAILAND

Figure 1. Physiographic regions and main rivers of Thailand.

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quality standards for Thailand (Table 1) anddeveloped 5 classes or levels of water qualitystandards according to their major usage,namely: a) Class 1, refers to extra clean freshwater resources used for conservation and onlyrequire ordinary treatment process forpathogenic destruction; b) Class 2, very cleanfresh surface water which is used forconsumption, aquatic organisms conservation,fishery and recreation; c) Class 3, medium cleanfresh surface water used for consumption and

agriculture; d) Class 4, fairly clean surfacewater resource used for consumption but requirea special treatment process before use; and e)Class 5, the resources which are not qualified inclass 1-4 and is mainly used for navigation.However, only 3 classes of these standards havebeen attributed to the Chao Phraya River. Theupper part (stretching from 142-379 km from thenorth of the river) comes under class 2, themiddle part (from 62-142 km) under class 3, andthe lower part (from 7-62 km) under class 4.

Table 1. Surface water quality of Chao Phraya River.

Parameters

TemperaturepHDOBOD 5d, 20°CColiform bacteriaTotalFecal

NO3-NNH3-NPhenolsCuNiMnZnCdCr (+6)PbHg (total)AsCNRadio-activity- Gross a- Gross ß

Pesticides- DDT- BHC- Dieldrin- Aldrin- Heptachlor &

Heptachlor epoxide- Endrin

Units

°C

mg Hmg l"1

MPN 100 ml*1

MPN 100 ml-1

mg 1'1

II

II

II

II

Becquerel l"1

mg I'1

MglJ

"••<•

"

Statistic

--

P20P80

P80P80

Max. allowance

H

"

H

"

"

"

1

nnnn

nnnnnnnnnnnnn

nnnnnnn

nn

Standard Values for2n

5-96

1.5

50001000

0

3

n5-94

2.0

200004000

< 5.0>0.5

0.0050.10 .11.01.0

.005*, 0.05**0.050.050.0020.010.005

0.11.0

0.051.0

0.020.10 .1

0.2

<none>

Class***4 5n

5-92

4.0

-

-----

---

--

------

-

Note:

Source:

Percentile value= naturally= naturally but changing not more than 3 C= Water Classification= When water hardness not more than 100 mg I"1 as CaCO3= Water Classification

Notification of the Ministry of Science, Technology and Energy B.E. 2528 (1985), published in the RoyalGovernment Gazette, Vol. 103, Part 60, dated April 15, B.E. 2529 (1986).

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Monitoring Stations

Thirty-two sampling stations have beenselected to monitor the water quality in the ChaoPhraya River starting from its estuary (km 0) tothe farthest upstream station (km 379). Resultsobtained showed that the downstream of ChaoPhraya dam was influenced by sea water,especially when the flow was so small that seawater intrusion could be found up to 175 km (4).In case of flow rate over 4,000 cu. cm, the impactwas obvious only at 75 km. However, the waterflow rate in Chao Phraya River variesseasonally, i.e: - low steady flow in January toMay and gradually higher from May onwards.This flow variation also influences the waterquality.

Two sampling intervals were performed:twice in the upper part (April and October) andfour times in the middle/lower part (February,April, July and October). From the existing waterquality monitoring data collected by variousgovernment agencies, it is evident that ChaoPhraya River is in a very critical condition. Thevisual characteristics of water like colour andodour emphasize this fact. The characteristicswhich signify the extent of organic pollution usedin this evaluation are dissolved oxygen,biochemical oxygen demand, total and fecalcoliforms, ammonia nitrogen, total phosphorus,lead and dieldrin. Such water qualitycharacteristics are depicted in graphs as shownin Figures 2 to 9. These data were obtained fromthe Office of the National Environment Board(ONEB), Metropolitan Water Works Authority ofThailand (MWA) and from the Department ofPublic Health (DPH).

The existing water pollution in the ChaoPhraya River is described below.

Dissolved oxygen (DO):The monitoring result during 1985-1989

revealed that there was a yearly declining trendof dissolved oxygen in the Chao Phraya River. DOin the lower portion of the river nowadays is lessthan the standard limit of level 4 (2 mg I"1). Itoften occurs that especially, the lowest value indry season, the DO in the lower Chao Phraya wasdecreased to less than 1 mg I'1.

In the middle or upper portions of ChaoPhraya River, the DO levels were inferior tostandard levels 3 and 2 (4 and 6 mg I"1) and had atendency to decrease. Despite of a little bit highertrend during the year 1986-1987, the under-standard value again occurred during 1988-1989when the DO in the monitoring station dropped

into the range of 2.8-3.5 mg I'1. Hence, a criticalDO situation in the middle and lower portions ofthe Chao Phraya River is going to decrease everyyear.

Biochemical oxygen demand (BOD):The BOD levels in some stations in the

upper, middle and lower portions of Chao PhrayaRiver were inferior to the BOD standard levels 2and 4 (1.5 and 4 mg I'1). Therefore, an urgentmitigation plan must be implemented before thewater quality becomes critical.

Coliform bacteria:The total coliform bacteria in the lower

Chao Phraya River in 1990 was 1.07-3.55xl05

MPN 100 ml"1 from the previous figures of 0.78-1.24xlO5 MPN 100 ml"1 in 1985. On the other hand,the coliform bacteria in some stations in themiddle portion of the river has already exceededthe standard level 3 (20,000 MPN 100 ml"1) and isforeseen to be even higher these years. In theupper portion of the river, the increasingcoliform bacteria level was in the range of 8,000-51,800 MPN 100 ml'1 in 1989 from the range of7,000-24,000 MPN 100 ml"1 in 1985. Similarly,the fecal coliform bacteria concentration since1985 has already exceeded the standard valuesespecially in the lower and middle parts of theriver. This is also expected to increase evenhigher these years.

Ammonia nitrogen (NH3-N) and phosphorus (P):The NH3-N and P concentrations were

observed higher in the lower part of the river.The analysis also showed that NH3-Nconcentration in the lower part was found greaterthan that of the standard (0.5 mg I"1) whereas inthe middle and upper parts were still within thestandard. Unfortunately, there is no existingstandard for phosphorus as of these days. Thus, amove to implement a standard for phosphorusshould be carried out.

Regarding the pollution caused by heavymetals and insecticide residues, which wereanalyzed from the data of lead and dieldrincontent, respectively, there is some indicationthat this problem may exist; however a clear cutconclusion cannot be drawn due to the limitedavailability of data. Other parameters were foundto be multiples of the standard levels.

In summary, the increasing trends along the376.4 km length of Chao Phraya River was due tothe increased of domestic loading beingdischarged directly into the river from the rapidpopulation growth and also due to the lack of

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"¡WO 1989 19881987

enE

w

OP

Year

S

oQ

Sid. level 2

'80 '82 '84 '86Year

'88 *90 '80i i

"82

Sid. level 4

'9U

2.1 DO at Upper part (km 286 2.2 DO at Middle part (km

from River moulli, Chaînât 95J f r o m R i v e r I n o u l h >

„ . Sainlae, PathumlhaniProvince) „

rrovuicej

'84 '86 '88 '90 '80 »82 '84 '86Year Year

2.3 DO at Lower part (km27 from River inoulli,('lira. KJianung)

sn

OQ

level 2

level 3 l/<h\

level 4 \i i i._

VX) 200"100Distance from Hie River

Mouth (km)2A DO (1981)

200 100Distance from the River

Muutli (km)

2.5 DO (1986)

2OO IOO

Distance from the RiverMoulli (kin)

2.6 DO (1990)

Figure 2. DO in Chao Phraya River (1981-1990).

appropriate wastewater management. It isevident that water quality degradation problem ofChao Phraya River is very complex and is goingto be worst as time goes. Thus, mitigation andabatement of pollution should be given highpriority since the impacts of pollution areadverse and numerous. It affects the economic,

social status and personal health of all theindividuals depending on the river.

Evaluation of Water Quality

It is apparent that the deterioration of waterquality in rivers usually increases during the dryseason due to low flow thus, providing inadequate

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1981

en6,

ÛO«

QOm

•8ü '82 '84 '86Year

'88 '90 '80 '82 '84 '86Year

•88 '90 '80

3.1 UOD at Upper part(km 286 I rom Rivermouth, Chaînât Province)

3.2 BOD at Middle part(km 95.7 from Rivermuiilh, Sitmlae,Patliumlhani Province)

•84 '86 '88 '90

Year

3.3 BOD at Lower part(kin 27 from River inoulli,Phra KJianong)

5SO

QOm

level 4

level 3

level 2

1 .

Distance from the RiverMouth (km)

34 uoD (1981) 3.5

100400 300 200 100 0 400 300 200 100 0 <KX) 300 200 .v~ ,Distance from the River Distance from the River

Mouth (kin) Mouth (km)UOD (1986) 3.6 UOD (1990)

Figure 3. BOD in Chao Phraya River (1981-1990).

dilution. Simulation study revealed that duringthe March-April period, if the flow volume of 100cu.m sec"1 was released from the dam, the waterproduction was 28 cu.m sec"1, and the salinity was0.1-0.3 g I '1 . When the dam flow decreased to 70cu.m sec"1, the flow available for mitigation ofsalinity intrusion was less than 30 cu.m sec"1,resulting to a high salinity levels of 11.75 ppt (4).

On the other hand, simulation of water quality inthe Chao Phraya River showed that BOD5 willreach its maximum value at 50 km from the rivermouth and which will increase from 11 mg I"1 inthe year 1990 to 13-16 mg I"1 in 2000 and 2010,respectively. The length of river over which thedissolved oxygen sag curve will fall below 2 mgI"1 will extend upstream from a point 50 km from

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Year

4.1 Tolal Col i/brin Bacteriaat Upper part (km 252from River mouth.Chaînât Province)

4.2 Total Col i form Bacteriaal Middle part (km 114

from River mouih,Ayuthaya Province;

o

m

ôx

4.4

level 2

"83 '85 *87 '89Year

4.3 Total Coliform Bacteriani Lower part (km 42from River mouth, Krunj;Thep Bridge)

? u

V

» 0 t>0 NK) »0 «> M

Distance from the RiverMouth (km)

Tolal Col i Ion n Bacteria(1981)

Distance from the RiverMouth (km)

4.5 Total Coliform Bacteria(1986)

Dislance from RiverMouth (km)

4.6 Total Col i form Bacteria(1990)

Figure 4. Total Coliform Bacteria in Chao Phraya River (1981-1990).

the sea by approximately 5 km in the year 2000and by 10 km in 2010. These predictions indicatethe necessity of introducing control measuresfor wastewater discharges to the Chao PhrayaRiver.

Sources of Water Pollution

The main sources of water pollution inThailand are: 1) domestic wastewater(residential and commercial), 2) industrial

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pi TC d

(4,009 »4.000 «1.000

IL,

V

OT8i;87838<i'858687*8889*90 °'81182'83'8'f8586'8T88'8990 'h '83 '85 '87 '89Year *ear Year

5.1 Fecal Colironn Bacteria at 5.2 Fecal Colirorm Bacteria at 5.3 Fecal Coliform BacteriaUpper part (km 252 from Midille part fkm 114 ironi RiverRiver month, Chaînât Province) »"«uili. Ayulhaya Province)

at Lower part (km 42 Iro.n

•c

lm 2

II58i l

5.4

level 2

f io t?O MO 140 «O V> lO

Distance I rom (lie RiverMouth (km)

Fecal Colilbrin Bacleriíi(1981)

»i, 000

level 3

level 2

\

level 3

level 2 11

5.5

Distance from .the RiverMouth (km)

Fecal Colifonn Bacteria(1986)

Distance from the RiverMouth (km)

5.6 Fecal Coliform Bacteria.(1990)

Figure 5. Fecal Coliform Bacteria in Chao Phraya River (1981-1990).

wastewater, 3) agricultural runoff, and 4) miningactivities (5, 6). ONEB reported that 40% of thepopulation load is generated from the residentialareas and about 32% of the waste load iscontributed by service-oriented activities, such

as restaurants, hotels, dormitories, marketplaces etc., 25% by the industries, and 3% by othersources. Other sources of wastes include:poultry, leachate from solid waste dumps, touristindustry, navigation, schools and golf courses.

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1985

M

S

1983

Year

s2 Std. level 2 Sid. level 3

'83 '85 *87Year

'89 *89•83 '85 '87 '89 '83 '8$ «87Year Year

6.1 NH,-N at Upper part 6.2 NI13-N at Middle part 6.3 NH,-N at Lower part

(km 286 from River mouth, Palhumtliani Province) (kin 27 from River mouth,

Cliainat Province) (k n l l ü l f r o i n R i v e r «n o u l h ' Pra Kanong. Bangkok)

--mi

CO

& 3level 4 I

level 3

level 2

<OO iOO KO 100

Distance from the RiverMouth (km)

level 4

level 3

level 2

6.4 NIlj-N (1983) 6.5

«ro 110 KO ¿o ¿

Diülance from the RiverMouth (km)

NU,-N (1986)

level 4

level 3

level 2

Distance from the RiverMouth (km)

6 - 6 Nllj-N (1990)

Figure 6. NH -N in Chao Phraya River (1983-1990).

The major polluting industries in Thailandare food brewery, paper and pulp, rubber, andtanneries. It has been reported that the number ofpolluting industries has increased from 159 in1969 to 20,221 in 1989. Industries in 1991 wereestimated to discharge about 525,235 tons of BODin the form of untreated wastewater (6).

Agriculture and farming contributesignificant BOD loads to the river. Agriculturalwaste includes organic matter, such as animalmanure, fish faeces, poultry wastes or drainagewater from plantations, and other substancessuch as pesticides runoff. Mining is anothermajor source of water pollution. In 1987, about 43

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Year

1°

oa.

1/??

on0.7

Ofi

050 1

030 ?P.»0

-

1 .n n

7.1

'83'84'85 '86'87 "88 '89 '90Year

Total Phosphorus atUpper part (kin 244 fromRiver inoulli, Chaînât

Province)

'83 "84 '85Year

•89 '90

Total Phosphorus atMiddle part (km lOlfrom River mouth,Palhumthani Province)

'83 '84 85 86 87 88 '89 90Year

7.3 Total Phosphorus atLower part (km 41 fromRiver mouth. Krunj;Thep Bridge)

•ioo soo

-0.6

as

0.1

0.3

02

a i

_ . . . . — - - <1O0 3O0 ZOO 100 0 <«OO SCO ?00 100 O

Distance from the River Distance from the River Distance from the RiverMouth (km) Mouth (km) Mouth (km)

7.4 Total Phosphorus (1983) 7.5 Total Phosphorus (1986) 7.6 Total Phosphorus (1990)

Figure 7. Total Phosphorus in Chao Phraya River (1981-1990).

million cubic meters of sediments have enteredThailand's river system. It is believed that 40million tons of sediments have been added to thenearshore area in Southern Thailand during thepast 20 years.

Environmental Impacts of Chao Phraya RiverPollution

Like the Thames or the Rhine river, the ChaoPhraya could be considered as a litmus test for

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Year

1983 1981

'87 89

Lead at Upper part 8.2 Lead at Middle part 8.3 Lead at Lower part(km 333 from River mouth, (km 114 from River (km 57 from River mouth,Naklmn Sawan Province) mouth. Ayuthaya Province) Nonlliabiiri Province)

I1

01035O.'

0 2507OIF01

005O - i -

100—j

300 ÎOO M)

Distance from Mie RiverMouth (km)

400 3f>0 ?00 100Distance from th1* River

Mould (km)

300 700 100Distance from the River

Mouth (km;

8.4 Lead (1981) 8.5 Lead (1986) 8.6 Lead (1990)

Figure 8. Lead in Chao Phraya River (1981-1990).

the environmental protection efforts of thegovernment. Chao Phraya River is severelypolluted, in which deterioration of water qualityhas been observed along almost the entirestretch. If effective wastewater control measuresare not adopted soon in Bangkok Metropolis,anaerobic conditions will persist in the lowerpart of the Chao Phraya River during low water

conditions. In such case, most of the micro-organisms normally will breakdown and thewater will become black and foul-smelling andthe low DO levels will hardly affect aquatic lifein the river. It has been reported (7) that somespecies of fish, such as Synaptura orientalis,Kryptopterus and Cynoglossus sp are no longerpresent in the lower section of the

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Sid.

*ioo 300 200 100

Distance from Hie River Mouth (km)

a) at Chao Phraya River (1985)0.16

2

Sid.

1981 1982 1983 1984 1985 1986 1987 (988 1989 1990

Year

b) at Samlae, Pathumthani Province (1981-1990)

Figure 9. Dieldrin concentration.

river. In addition, red tide has become a commonphenomenon in the upper Gulf of Thailanddue to the excessive blooms of Noctilucacaused by the huge amount of nutrientsand organic pollutants that are drained into theGulf.

With the continuing growth of urbanpopulation and industrial outputs, the pressure onwater quality is becoming intense in Thailand.In short, the implications of pollution of the ChaoPhraya River are wide ranging and could affectvarious socio-economic aspects of life such asthe health of the community, agriculture,

transportation, and the economy as a whole. TheTDRI studies revealed that if the river is notrestored soon, the society will lose an income ofabout Baht 1,000 million per year in terms of highcost water supply production, reduction of landprices, and low quality of life and health andsanitation. This problem is believed to beaggravated if the population of Bangkok reaches12 million by the year 2000 (8).

Managing Water Supply and Demand

Water use in the Bangkok Metropolitan

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Region (BMR) is mainly for: 1) domesticconsumption and commercial activity, 2)industry, and 3) agriculture. Water demands fordomestic consumption, commercial andindustrial purposes are provided by severalpublic utilities as well as by extraction fromgroundwater sources. Water for agriculture ismainly taken from the rivers and canals.

As a consequence of urbanization,industrialization and income growth, the demandfor water for non-agricultural use has increasedto a high level. The demand for water in BangkokMetropolitan Region grew at a compound rate of8% per year in the 1980's and is expected to groweven faster in the 1990's (9). The water demandfor industrial sector and tourism is increasingdramatically leading to water shortage which canonly be satisfied by environmentally destructivemethods such as intensive abstraction and overabstraction of groundwater aquifers (10).

Another reason for the current watershortage is due to late rains in which the water inmajor dams on the Chao Phraya river has fallenwell below the "safety" levels. It was reportedthat Bhumibol dam has only 67 million cubicmeters of water compared with 181 million cubicmeters in 1991. Similarly, the Sirikit dam hasonly 87 million cubic meters of water comparedwith 347 million cubic meters in 1991.According to the Department of Irrigation, thisproblem could be attributed due to increaseddemand for water by farmers in irrigated areas,lack of an efficient water management system,fierce competition among farmers upstream anddownstream for the reduced amount of wateravailable, contamination of water by industrialplants and use of chemicals by farmers, andfailure by farmers and residential users to co-operate with the authorities in waterconservation.

Therefore, it is evident that water is beingoverexploited and that a water shortage islooming. As man's activities require arelatively constant and increasing amount ofwater, water will gradually become more likeprecious ores. Users will have to pay for it aswell as for wastewater discharge, which will becharged on the basis of both quantity and quality.Water rights and allocation plans will have to beset up to minimize and mediate conflicts.

Water Pricing

Water charges have been in effect inBangkok since 1914 and the present pricingsystem is provided in Table 2. The response of

residential water demand to change in waterprice is slightly less elastic than that of theservice sector. The elasticities of demandobtained indicate that a 10% increase in pricewill reduce water demand in residential sectorby 2.8% and service sector by 3.1% (9).

The demand management can be donethrough appropriate price setting. Water shouldbe charged according to its full marginal cost.Appropriate price setting not only regulateswater demand but also recovers full cost ofsupply and provide incentive and resources forsupply expansion. The importance of the twoeffects is given in Table 3.

The estimated water consumption and pricefor 1990 is used as a base scenario. Based on theprice elasticities of demand and assuming waterprice increases from the effective rate of Baht6.2 per cubic meter per month to Baht 9 per cubicmeter per month, water demand declines by 13%and the revenue increases more than a quarter.Thus, a less than 50% increase in the effectiveprice reduces the pressure on water supply bymore than 90 million cubic meters. In addition,more than Baht 1.1 billion of revenue isgenerated which can be used to expand the supplyby more than 120 million cubic meters of water atan average cost of Baht 9 per cubic meter.

This procedure does not apply to large priceincreases above the current price. Beyondcertain level the increase in price may not resulton any reduction in the quantity of waterdemanded but the resulting grievance andhardship can create social and politicalpressures.

Laws Concerning Water Quality Management

In Thailand, laws concerning waterpollution are fragmented. There are more than20 Acts addressing issues relating to theutilization, management and conservation ofwater, including the treatment of wastewater (6).However, only a few regard the prevention ofpollution as their primary goal, as follows:Public Health Act B.E. 2535 (1992); Cleanlinessand Tidiness of the Country Act B.E. 2503 (1960);Building Construction Control Act B.E. 2522(1979); Factories Act B.E. 2535 (1992);Navigation in Thai Water Act B.E. 2456 (1913);Enhancement and Conservation of NationalEnvironmental Quality Act B.E. Act 2535 (1992);Announcement No. 286 of the RevolutionaryCouncil, 1972; Hazardous Substances Act, 2535;The Minerals Act B.E. 2510; The GroundwaterAct B.E. 2520; The Fisheries Act B.E. 2490; The

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Table 2. Water tariffs in Bangkok (Source: TDRI, 1990).

Category 1

Volume (cu.m)

0-30

31-4041-5051-6061-7071-8081-9091-100101-120121-160161-200Over 201

: Residence

Rates(Baht cu.m"1)

4.0 (but not lessthan Baht 20)4.254.504.755.005.256.156.406.656.907.157.65

Category 2:Enterprise,

Business StateGovernment

Agency, OthersVolume(cu.m)

0.1

11-2021-3031-4041-5051-6061-7081-100101-120121-160161-200Over 201

Rates(Baht cu.m"1)

Package rateBaht506.206.456.706.957.207.457.707.958.208.458.70

Category 3:

Volume(cu.m)

0-10

11-2021-3031-4041-5051-6061-7081-100101-120121-160161-200201-20002001-40004001-60006001-1000010001-2000020001-3000030001-4000040001-50000Over 50001

Industrial

Rates(Baht cu.m"1)

Package rateBaht 506.206.456.706.957.207.457.707.958.208.458.608.408.007.507.006.506.005.505.00

Table 3. Changes in water demand and revenue resulting from price increase.

Quantity (Million Baht cu.m'1) Revenue (Million Baht)Scenario

Base

With priceincrease

Change

Price(Baht cu.m'1)6.2

9.0

+2.8

Residential400

349

-51

Services300

258

-42

Total700

607

-93

Residential2,480

3,141

+661

Services1,860

2,322

+462

Total4,340

5,463

+1,123

Provincial Authority Act, Municipal GovernmentAct, Sanitary District Act, City of Pattaya Act, andBangkok Metropolitan Act; and etc.

Policies Under the Seventh Economic andSocial Development Plan Development (1992-1996) - Guidelines and Measures forManagement of Water Resources are givenbelow:1. Prepare budgetary allocation plan for

development of all the water resources.

Require medium-scale water resourcedevelopment projects.Allocate budget for small-scale waterresources development.Designate pattern of administration andmanagement of the already constructed waterresources projects for agriculture, and forhousehold consumption.Accelerate setting up of a nationalorganization under the law to formulate plans

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for administration and management of waterresources.

6. Formulate work programs for procurement ofwater resources for water supply production,and formulate measures controlling waterquality.

7. Encourage detailed studies concerning thepotential of various sources of groundwater,as well as formulate a master plan forgroundwater resource development.

8. Encourage setting up of water resourcesinformation system to support planning andpolicy formulation.

9. Revise rates of water fees as collected fromthe agricultural and non-agricultural sectors.Within the agricultural sector, the fees shouldreflect only the maintenance costs of thedistribution system, while in the non-agricultural sector, the fees should takeaccount of the construction and maintenancecosts of water distribution system.

Basic Strategy

The basic strategy for developing waterresources (11) consists of the followingelements: a) preparation of a work plan andbudget; b) large-scale multi-purpose waterresources projects shall need EIA study; c)control pumping of water for agriculture isnecessary; d) large-scale agricultural waterresources development projects shall bepreceded by full-scale feasibility studies; and e)development of water's use plan and databasesshall be fostered.

CONCLUSIONS

1. Since the water quality of Chao Phraya Riveris becoming worse every year, appropriateinvestment in wastewater treatment system,according to the economic situation and bestavailable technology for wastewatertreatment system should be implemented.The restricted zones in the river wherewastewater cannot be discharged should benotified. Furthermore, to ensure adequatemonitoring of river and effluent, moresample numbers should be carried out.

2. Recycling and re-use of water should becomethe rule wherever the resource is limited,with drinking water taking the priority in thecycle, followed by industry and, lastlyirrigation where the water is used up.

3. In order to limit the wastage and pollution inthe Chao Phraya, it is essential that there

should be a permanent system of incentivesbased on appropriate regulations andeconomic measures and increased rationaland effective pricing system. "Polluters payprinciple" presupposes the existence of asystem and facilities for measuring andassessing the quantity of water used and ofeffluents discharged by each user. Therevenues earned can be used for regional orlocal pollution-abatement programs and canalso be allocated as subsidies to industriesfor construction of wastewater treatmentfacilities.

4. Water conservation program such as low-flow toilet and shower systems should beadopted by BMR in order to minimize theusage of water. Besides, toilet and wastewaterpipes should be maintained properly.Detection and repair of leak should becarefully done to prevent leakage.

5. The poor enforcement by the governmentagencies concerned and their lack ofcommitment to the cause of solving ChaoPhraya pollution problem has in part beenresponsible for the failure to control thepollution level. Hence, effectiveenforcement of laws and regulations shall begiven more emphasis.

- Public awareness for environmentalconcerns should be effectively focused, thatboth the government and local authoritieswould have to undertake on a regular andsustained basis.Ministerial regulations for setting up aminimum standard for wastewater frombuildings as empowered by the BuildingControl Act should be issued and by-laws tohandle rubbish wastewater problems withinthe jurisdiction of each local authority asauthorized by the Public Health Act and theBuilding Control Act should be enacted.The penalty for violation of laws intended forthe protection of the environment should beraised and that trained manpower in agenciesresponsible for the enforcement of lawconcerning water pollution be increased. Co-operation and co-ordination among relevantagencies or industries in tackling waterpollution problems is highly needed so as toefficiently utilize the existing resources.Provisions shall be made to plan industrialestates, if possible shall shift the industriesto industrial estates. The industrial estates aswell as the big cities of Thailand shall beprovided with common treatment plants.

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A working group that is wholly responsibleand competent for management of the river,and revise on a long-term basis all the lawsrelating to water pollution should be created.In here, the Industrial State Authority ofThailand should be promoted and shall begiven the power to control environmentalproblems created by industries.The water shortage can be attributed mainlydue to lack of an efficient water managementsystem, discharge of untreated effluents fromdomestic activities and by the industrialsector polluting major water resources,deforestation, and rapid industrialization andurbanization. At the official level, theproblems are mainly due to lack of co-operation and co-ordination among privateand government sectors concerned, no lawsand regulations related to water resource andconservation, non-effectiveness of waterquality standards, regulations and penalties.

Hence, regulations and standards should beframed in a practical and flexible way, andthus easy to amend and adjust (in line withscientif ic , t echnica l and economicdevelopment).

7. Both supply management and demandmanagement for water resources must beconcurrently implemented. In Thailand thedemand management for water resources(e.g.. to conserve water) has been neglectedso far, while supply management (e.g..reservoir construction) predominates.

8. A study on the contribution of leachate fromdumpsites and wastewater from agricultureand mining to pollution in the Chao Phrayashould be commissioned. In addition, anintegrated computerized information centershould be set up and analytical quality controland in tercal ibra t ion program, amongdifferent concerned laboratories should becarried out.

REITEBENCES

1. ONEB/DPH, Annual Reports (1981-1990).2. AIT Research Report, Mathematical Optimization Model for Regional Water Quality

Management: A Case Study of Chao Phraya River. AIT, Bangkok, Thailand, 1978-1980.3 . Notification of the Ministry of Science, Technology and Energy B.E. 2528 (1985). Published in the

Royal Government Gazette, Vol. 103, Part 60, dated April 15, B.E. 2529 (1986).4 . Bangkok Metropolitan Region Wastewater Management Plan. Pollution Control Department,

Ministry of Science, Technology and Environment, Bangkok, Thailand (1993).5. UNDP/WORLD BANK, Sewage and Wastewater Management for Urban Areas in Thailand: Sector

Development. Asia Water Supply and Sanitation Sector Development Project, May 1991.6. Thailand Environmental Profile, Vol. 1 & 2 (O.E.C.F.), Soil and Water Ltd. (1992).7. AIT, Master Plan for Rural Water Supply and Sanitation in Thailand. Final Report, 3 Vols.

Prepared for the National Economic and Social Development Board, Bangkok, Thailand (1985).8. Proceedings of the National Seminar of Wastewater Management on Bangkok Metropolitan

Region with Reference to the Chao Phraya River. Bangkok, Thailand (1990).9. TDRI, Research Report No. 3, Water Shortages: Managing Demand to Expand Supply. Bangkok,

Thailand (1990).10. JICA Report, Final Report for the Study on the Effective Use of Industrial Water in the Kingdom of

Thailand. (1989).11. NWRC, Policies for the Development of Water Resources. Office of the National Water

Resources Committee, Bangkok, Thailand (1992).

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