environment of sg. sarawak: relationships between city and river

Sarawak Government/DANCED

Sustainable Urban Development Project, Sarawak

ENVIRONMENT OF

SG. SARAWAK:

RELATIONSHIPS

BETWEEN CITY AND RIVER

nreb State

Government

Danced

ENVIRONMENT OF

SG. SARAWAK:

RELATIONSHIPS

BETWEEN CITY AND RIVER

River Quality Baseline Study, Volume 1:

Main Report.

Existing River Quality,

Pollution Sources & Environmental Management of Sg. Sarawak

COWI Danwaste

Environment of Sg. Sarawak - Relationships Between City and River

Prepared by Erling Povlsen, COWI A/S with

Local Consultants Chemsain Konsultant Sdn. Bhd.

Daya Rancang 1st Edition (1st Print) September 2001

Copies: 400 The Authors and Danced Copenhagen

Quotations permitted with source credit

Printed by UM Colour Printing Company Report No. SUD-02-25

ISBN 983-40546-5-3

DANCED SARAWAK GOVERNMENT

Sustainable Urban Development Project

Natural Resources and Environment Board

River Quality Baseline Study Volume 1

Main Report

Existing River Quality, Pollution Sources and Environmental Management of Sg. Sarawak

Final

September 2001

NREB

Natural Resources and

Environment Board

DANCED

Danish Cooperation for

Environment and Development

DANCED SARAWAK GOVERNMENT

Sustainable Urban Development Project


River Quality Baseline Study Volume 1

Main Report

Existing River Quality, Pollution Sources and Environmental Management of Sg. Sarawak

Final

September 2001

Report no. SUD-02-25

Issue no. 02

Date of issue 4 September 2001

Prepared ERP, HBJ, Chemsain, Daya Rancang

Checked ILA

Approved ILA

River Quality Baseline Study. Vol. 1

C:\Documents and Settings\user\Desktop\SUD-02-25 - River quality baseline study Vol.1 by Erling\final\River Quality Baseline main report.doc

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Table of Contents

1 Summary 4

2 Introduction 13

2.1 Background 13

2.2 River Quality Baseline Study 14

3 Data Compilation 18

3.1 Compilation of Existing Data 18

3.2 Supplementary Field and Desk Studies 19

3.3 Assessment of Collected Data 19

4 Background Conditions 21

4.1 River and Catchment areas 21

4.2 Physical Background Conditions 25

4.3 River Ecosystem 28

4.4 Landuse 32

4.5 River Quality Management in Kuching 39

5 River Quality 43

5.1 Potential Impacts of the Discharge of Wastewater 43

5.2 Surface Water Quality 46

5.3 Sediment Quality 60

5.4 Accumulation of Pollutants in Organisms 76

5.5 Ecosystem Impacts 77

5.6 Floating Debris 81

6 Sources of Pollution and Pollution load 83

6.1 Overview of Pollution Sources 83

6.2 Pollution from Households 84

6.3 Pollution from Food Outlets 91

6.4 Pollution from Industries 95

6.5 Pollution from Agriculture 100

6.6 Other Sources of Pollution 103

6.7 Other Sources of River Quality Deterioration 106



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7 Discussion and Conclusion 108

7.1 Degree of Pollution 108

7.2 Sources 108

7.3 Existing Technical Measures to Reduce Pollution Loading 115

7.4 Existing Control and Enforcement Measures 116

7.5 Assessment of Preliminary Indicators 116

8 References 121

Appendix 1. Data on surface Water Quality 1999 and 2000

Appendix 2. An Overview of the State Administration

Appendix 3. A summary of Relevant Activities and Mandates



3

Abbreviations

Amm-N Ammoniacal Nitrogen

As Arsenic

BOD Biochemical Oxygen Demand

Cd Cadmium

Cl Chlorine

CBD Central Business District

COD Chemical Oxygen Demand

Cr Chromium

Cu Copper

DBKU Dewan Bandaraya Kuching Utara (Kuching North City Hall)

DID Department of Irrigation and Drainage

DO Dissolved Oxygen

DOE Department of Environment

EMS Environmental Management System

EMT Environmental Management Team

EQA Environmental Quality Act

Fe Iron

Hg Mercury

INWQS Interim water quality standard

JKR Jabalan Karja Raya (Department of Public works)

KBM Kuching Barrage Management Sdn Bhd

KWB Kuching Water Board

L & S Land and Survey Department

LSI Large Scale Industries

MBKS Majlis Bandaraya Kuching Selatan (Kuching City South Coun-

cil)

MID Ministry of Industrial Development

Mn Manganese

MPP Majlis Perbandaran Padawan (Padawan Municipal Council)

NO3-N Nitrate – Nitrogen

NREB Natural Resources and Environment Board

O & G Oil and Grease

PAH Polyaromatic Hydrocarbon

Pb Lead

Sg. Sungai (River)

SHD State Health Department

SMI Small-Medium Industries

SPU State Planning Unit

SRB Sarawak Rivers Board

SUD Sustainable Urban Development

Tot-N Total Nitrogen

Tot-P Total Phosphorous

TPH Total Petroleum Hydrogen

TSS Total Suspended Solids

UNIMAS University of Malaysia Sarawak

Zn Zinc



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1 Summary

A baseline study of the river quality of Sg. Sarawak and tributaries has been

carried out in connection with the development of an Environmental Manage-

ment System (EMS) for Kuching. The objective of the baseline study is to pro-

vide a description of the river quality and sources of pollution with a view to

make it possible to set realistic goals and indicators for the future river quality

in the EMS.

The report describes:

The background conditions necessary for the interpretation of river quality

data (climate, geology, hydrography, river bed sediments, flora, fauna, river

ecosystems and landuse);

The present river quality in terms of surface water quality, sediment quality

and ecosystem impacts of pollution;

The existing sources of pollution and the load from these; and

The recommendations for revision of preliminary indicators based on re-

sults of the baseline study.

The report will be used as a basis for the specifications of formats for the EMS,

in terms of River Quality. The major findings are summarised below.

THE SG. SARAWAK RIVER SYSTEM

Sg. Sarawak has two principal tributaries namely Sg. Sarawak Kiri and Sg. Sa-

rawak Kanan, rising in the mountain ranges to the south of Kuching at the bor-

der to Indonesia. The two tributaries meet near Batu Kitang, some 34 km up-

stream of Kuching. From Batu Kitang the mainstream Sg. Sarawak meanders

across a wide coastal flood plain and through the city of Kuching. Downstream

of Pending, the industrial area in the eastern part of the city of Kuching, Sg.

Sarawak confluence with Sg. Kuap and further downstream by Loba Batu Belat

at further downstream before discharging to the South China Sea at Muara Te-

bas.

In Kuching City, several small tributaries discharge to Sg. Sarawak including

Sg. Maong, Sg. Bintangor, Sg. Padungan Sg. Sekama, Sg. Bintawa and Sg.

Biawak.



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A total of 21 drainage sub-catchement areas in Kuching are discharging into the

part of Sg. Sarawak, which is flowing through Kuching. The remaining part of

the city, including the Sama Jaya Free Industrial Zone drains to Sg. Kuap.

In 1997, a gated barrage was constructed through the Sejingkat Isthmus and the

river was blocked by causeways at Jalan Keruing and Jalan Bako in order to

regulate the tidal influence on the river.

RIVER QUALITY

The present river quality has been assessed in terms of:

Surface water quality

River Sediment quality

Pollutants in organisms

Ecosystem impacts

General

The baseline study has documented that the tributaries of Sg. Sarawak situated

in Kuching City and the part of Sg. Sarawak, which is flowing through

Kuching, is significantly polluted.

The major issues are serious pollution with faecal derived coliform bacteria,

which is posing a health risk and pollution with organic matters and nutrients,

leading to oxygen deficiency, deleterious impact on bottom fauna and offensive

odours. The main source of the pollution is raw and insufficiently treated sew-

age and wastewater, which is discharged to the open drains in the city.


The water quality of different zones of the entire river system have been classi-

fied according to the Malaysian Interim National Water Quality Standards

(INWQS). A summary of the results of the classification is presented in Table

1.1.

The water quality in the tributaries Sg. Maong, Sg. Bintangor, Sg. Padungan

Sg. Sekama and Sg. Tabuan in the city is very poor and falls between the class

IV and class V of the INWQS. Very high concentrations of BOD and ammo-

niacal nitrogen and very poor oxygen conditions are encountered. The concen-

trations of oxygen are in fact so low that only very few organisms, if any can

survive in the water (i.e. concentrations consistently below 2 mg/l). The content

of faecal derived bacteria is extremely high and the water poses a health risk.



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Table 1.1 Summary of INWQS classification of the different zones of the Sg.

Sarawak system.

Zone INWQS

Physical-chemical

parameters

INWQS

Bacteriological pa-

rameters

Zone A (Sg. Sarawak Kanan) IIA/IIB

Zone B (Sg. Sarawak Kiri) IIA/IIB

Zone C (Sg. Sarawak Proper from Batu

Kawa to upstream Satok bridge)

IIA/IIB III

Zone D (Sg. Sarawak Proper from Sa-

tok Bridge to downstream of barrage)

III V

Zone E (Sg. Maong) IV/V V

Zone F (Sg. Bintangor) IV/V V

Zone G (Sg. Padungan) IV/V V

Zone H (Sg. Sekama) IV/V V

Zone I (Sg. Tabuan) IV/V V

The water quality in the stretch of the Sg. Sarawak Proper, which is running

through Kuching, is better than in the tributaries but relatively low concentra-

tions of oxygen and somewhat elevated concentrations of NH4-N are encoun-

tered. The water can be classified as Class III in terms of physico-chemical pa-

rameters. However, in terms of bacteriological parameters, the water is only

Class V.

The water quality in Sg. Sarawak upstream of Kuching, including Sg. Sarawak

Kiri and Kanan is quite good and generally complies with class IIA/IIB in

terms of physico-chemical parameters. However, the water does not meet the

class IIB standards for faecal derived bacteria.

There is no or very little odour in the water of Sg. Sarawak Proper. In contrast,

the water in the tributaries such as Sg. Bintangor and Sg. Sekama as well as

some drains is quite smelly.

The levels of heavy metals in water are generally very low and below the detec-

tion limits even in the very polluted tributaries.

The concentrations of iron and manganese are generally high and violating the

INWQS standards. The high iron and manganese concentrations are not primar-

ily due to human activities. The presence of high concentrations of iron and

manganese in surface water are common in tropical natural waters, especially in

swampy areas. Here, the anaerobic conditions in soils induce the mobilisation

of insoluble iron compounds to soluble iron due to chemical reduction proc-

esses. Manganese reacts the same way as iron.

The concentrations of agrochemical and pesticides are generally below detec-

tion limits in surface water samples.



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Sediment Quality

Organic matter and heavy metals from outlets in Kuching are clearly accumu-

lated in the sediments of Sg. Sarawak. This results in elevated loss on ignition

and elevated concentrations of Tot N, Tot P, NH4-N, Pb, Cu, Ni, Cd, Cr, As and

Zn along the stretch of the river from downstream of the confluence of Sg.

Maong and Sg. Sarawak to the area off Kuching Port Authority.

The concentrations of pollutant decrease further downstream around Pending;

probably due to the flushing procedure at the barrage. If the flushing were not

carried out it is expected that elevated concentrations of pollutants would also

be encountered in this area.

The concentrations of heavy metals, except Hg, are well below potentially toxic

levels. Hg is found in concentrations, which is potentially toxic to sensitive or-

ganisms according to recently developed Canadian Sediment Quality Criteria.

The major source of Hg is not from the city as potentially toxic levels are al-

ready encountered at the upstream of Kuching. The possible source may be

from previous mining activities between Bau and Buso.

Metals originated from the previous gold mining activities and perhaps quarry

operations in the area between Bau and Buso have resulted in elevated concen-

trations of heavy metals significantly in the sediments of Sg. Sarawak Kanan.

Very high and toxic concentrations of As and Hg have been encountered. Quite

high concentrations of Cd, Cr and Pb have also been found.

The concentrations of heavy metals in Sg. Maong are higher than those found

in Sg. Sarawak and potentially toxic levels of Cd, Pb and Zn are encountered.

Heavy metals from the Sama Jaya Free industrial Zone are accumulated in the

sediments of Sg. Kuap. The concentrations of heavy metals (Cu, Pb, Ni, Cr, Cd

and Zn) increase markedly from upstream of the industrial estate to the areas

off and downstream of the estate. Although heavy metals are accumulated in

the sediments, the concentrations are below levels, which are likely toxic to

aquatic organisms.

Pesticides and Polyaromatic Hydrocarbons (PAH) are not found in the sedi-

ments at the studied sites in Sg. Sarawak and Sg. Kuap. Elevated concentrations

of total hydrocarbons were encountered at Satok Bridge and off Sg. Bintawa.

Pollutants in organisms

Freshwater molluscs living in the contaminated sediments between Buso and

Bau have accumulated Cu and Zn to levels, which could pose a risk to consum-

ers. The levels of As are also considerably high. There are no data from the part

of the river running through Kuching.

Ecosystem impacts

The high load of organic matter from Kuching clearly affects the benthic fauna

in Sg. Sarawak.



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At some sites, the organic load is apparently so high and the supply of oxygen

from exchange of oxygen rich water so low that poor oxygen conditions in

sediments results in the decrease in density (abundance) and number of species.

This seems to be the case downstream of the confluence to Sg. Maong and at

the Satok Bridge.

Off Sg. Bintagor and off Kuching Port Authority high organic loads apparently

results in a significantly increased abundance and number of species, the reason

probably because of the organic matter constitute an increased amount of food

without being so high as to cause oxygen depletion.

SOURCES OF POLLUTION AND POLLUTION LOAD

The poor water quality in the tributaries and the part of Sg. Sarawak traversing

through Kuching is clearly due to the discharge of untreated sewage from the

drains in the city.

Estimation of pollution loads to Sg. Sarawak from households, food outlets and

industries has been carried out in order to identify the source of the most severe

pollution of Sg. Sarawak in Kuching City. The estimations include loads from

the sub-catchment areas discharging to Sg. Sarawak from (and including) Sg.

Maong to the causeway east of Pending. The areas discharging to Sg. Tabuan

and Sg. Kuap are not included in the estimates.

In general, untreated sewage from households is identified as the most signifi-

cant source of pollution as a whole. The loads of BOD, COD, TSS, Tot-N, Tot-

P and oil and grease from households are orders of magnitude larger than the

loads from food outlets (markets, food centres, restaurants etc.), industries and

other sources (Table 1.2).

However, food outlets (restaurants, markets etc.) are the significant local source

of pollution in the Central Business Centre immediately south of Sg. Sarawak.

In sub-catchment areas Bintangor 2, Bintangor 3, Padungan, Periok and Bia-

wak, 20-40% of the BOD load and as much as 71-83% of the load of oil &

grease are discharged from food outlets. In Sekama and Bintawa, 83 and 71%

of the oil and grease is from food outlets. Presently, the Local Councils actually

spend huge resources in cleaning the oil and grease in the drains downstream

due to the inadequate treatment facilities.

The most significant load of organic pollution is at the Maong sub-catchment

area, followed by Padungan, Bintawa1 and Seman Lama. The highest loads of

heavy metals are encountered in the Pending area (Sekama 1, Periok, Biawak,

Bintawa, Bintawa 1), Padungan and Maong.

The total load of BOD from the Sg. Kuap catchment (not included in the esti-

mates above) has been roughly estimated at 3,000-4,500 kg/day, which is the

same magnitude as the discharge from the Sg. Maong catchment.

Pig farm located at the upstream of Kuching is also one of the significant

sources of pollution to Sg. Sarawak.



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Table 1.2 Estimated loads of pollutants to Sg. Sarawak and tributaries from

different types of sources in Kuching. (Rounded figures).

Households Food outlets

(Markets, Food

centres, Restau-

rants etc)

Industries Other

BOD kg/day 5900-9700 650 15 50

COD kg/day 19900-26000 800 40 90

TSS kg/day 5400-8000 260 60 40

Tot-N kg/day 2600-3400 30 5 2

Tot-P kg/day 500-600 10 3 2

Oil & grease kg/day 200-350 60 2 2

Pb kg/day - - 0.02 -

Cd kg/day - - 0.002 -

Cu kg/day - - 0.01 -

Zn kg/day - - 0.7 -

Fe kg/day - - 0.9 -

Mn kg/day - - 0.07 -

Al kg/day - - 0.9 -

AOX kg/day - - 0.009 -

STATE OF TECHNICAL MEASURES TO REDUCE POLLUTION

The City of Kuching does not have a functional wastewater treatment system.

Almost all houses in Kuching discharge untreated greywater directly to the

stormwater drains in the city, which later drain into the tributaries (Sg. Maong,

Sg. Bintangor, Sg. Padungan etc.) or directly to Sg. Sarawak. Consequently, the

sewage from the houses does not comply with the standards, which are stipu-

lated in the Environmental Quality (Sewage and Industrial Effluents) Regula-

tions, 1979.

The houses are equipped with individual septic tanks, which receive the black-

water. Septic tanks are generally not very efficient. Only about 30 % of the or-

ganic matter and no nutrients are removed prior to discharge, even with the

most efficient type of septic tanks. In addition, the septic tanks in Kuching are

generally not functioning due to improper desludging. As a consequence,

blackwater is discharged almost untreated to the drainage system. Untreated

blackwater is undoubtedly the main source contributing to the extremely high

levels of faecal coliforms in the tributaries and Sg. Sarawak Proper.

The food outlets also generally discharge untreated wastewater directly to the

drains although thereare some inefficient treatment facilities exist. At present,

information on the number of food outlets with treatment facilities is not avail-

able.

In general, the sewage from food outlets does not comply with the regulations

of 1979.



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Many industries have their own wastewater treatment system. However, there

are a few industries with or without inadequate systems. Presently, data on the

number of industries with or without a proper wastewater treatment system are

not available.

In the SUD field study, it was observed that the industries equipped with proper

treatment facilities complied with the regulations, whereas those without facili-

ties or with inadequate facilities did not.

The findings of this study clearly indicate that the water quality of the Sg. Sa-

rawak and its tributaries could be improved by establishing efficient sewage

treatment of sewage for households.

The study has also shown that introduction of regular desludging of septic tank

will not improve the water quality significantly. Estimates has indicated that

even if all septic tanks in Kuching were desludged regularly and functioning

properly, the effect in terms of reducing the load to the tributaries and The

River still be insignificant. The discharge of BOD from blackwater will still be

high and the discharge of nitrogen and phosphorous are not reduced at all.

Introduction of proper treatment facilities at food outlets in the Central Busi-

ness Centre at the south of Sg. Sarawak will also significantly improve the wa-

ter quality locally.

STATE OF CONTROL AND ENFORCEMENT MEASURES

The enforcement measures are generally passive, i.e. only in case of com-

plaints, authorities carry out inspections and may impose a fine to the offender.

There is currently no specific active enforcement measure carried out by the

authorities to control the sewage discharge from households and/or food out-

lets. Other than cleanliness campaigns and awareness programmes, no direct

inspection or regular checks on the discharge has been made.

The Department of Environment (DOE) is monitoring the wastewater from a

small fraction of the industries in Kuching for compliance to the Environmental

Quality Act, 1974 (EQA). The monitored industries include: industries dis-

charging more than 60 m3 wastewater per day or where the total load of BOD

in effluents exceed 6 kg per day, industries involved in the processing of oil

palm fruit and raw rubber.

NREB is regulating the outlets from pig farms and other livestock.

EFFECT OF THE BARRAGE

Kuching Barrage Management is currently operating a flushing scheme to miti-

gate environmental impacts of the barrage. Potential impacts, which are miti-

gated by the flushing scheme, include:

Reduction of saltwater intrusion and river flow velocity;



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Increase of sedimentation of suspended matter due to reduction of flow ve-

locities;

Increased risk of oxygen depletion and accumulation of organic material,

nutrients and bacteria upstream of the barrage;

Risk of impacts on mangroves and nipah forests due to the decreased salin-

ity;

Risk of reduction of the stock of the giant freshwater prawn which is an

important commercial species, due to blocking of migration routes to and

from spawning and nursery grounds downstream of the barrage; and

Reduction of the population and catch of marine and brackish-water species

fish in the river due to reduced salinity.

Should the flushing scheme for some reason be inadequate in the future, there

is a risk that measures to improve the water quality may be affected by the

presence of the barrage. The interpretations of state indicators in the EMS

should therefore always be related to the operation of the barrage.

RECOMMENTATIONS IN TERMS OF EMS

The baseline study has indicated that:

Some of the selected preliminary indicators are not suitable as indicators;

Some of the preliminary indicators should be modified; and

Some new indicators should be added.

An overview of the proposed modifications of the preliminary state indicators

is presented in Table 1.3. Arguments for the proposals are discussed in section

7.5.

It is proposed that all preliminary load indicators be used in the EMS. In addi-

tion it is proposed, that estimates of loads from households, food outlets and

industries be used, applying the methods used in the baseline study.



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Table 1.3 Overview of modifications of preliminary state indicators for the

EMS for river quality.

Preiminary indicators

proposed to be included

in EMS

New indicators proposed

to be added

Preliminary indicators

proposed to be excluded

from the EMS

Surface water

quality

DO, pH, BOD, COD,

TSS, Ammoniacal ni-

trogen (NH4-N), Nitrate

(NO3), Phosphate (P),

Faecal coliforms, Total

coliforms.

Heavy metals (Hg, Pb,

As, Zn, Cd, Cr, Cu, Ni,

Fe, Mn)

PAH, Total petroleum

hydrocarbons

Sediment

quality

Nutrients (NH4-N, NO3),


As, Zn, Cd, Cr, Cu, Ni, )

PAH, Total petroleum

hydrocarbons

Loss on ignition

Total N

Total P

Fe, Ni

Pollutants in

aquatic organ-

isms


As, Zn, Cd, Cr, Cu, Ni)

Polyaromatic Hydrocar-

bons, PAH, Total petro-

leum hydrocarbons

(TPH) in transplanted

mollucs

Ecological

(biological)

parameters

Diversity of benthic

macroinvertebrates

(Shannon Wiener).

Cpu (catch per unit effort

of giant prawn (Macro-

brachium rosenbergii)

and the fish species Mys-

tus spp. and Oxyeleotris

marmorata

Number of species,

abundance (no individu-

als/m²) and species com-

position of benthic inver-

tebrates

Catch per unit effort of

all fish and prawn spe-

cies in a catch

Invertebrates of zz

family

Aesthetics Volume of floatables

collected from Sarawak

River.

Threshold odour number

Number of complaints of

smell in river, drains and

tributaries



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2 Introduction

2.1 Background

In June 1999, the State Government of Sarawak initiated the Sustainable Urban

Development Project in collaboration with the Danish Cooperation on Envi-

ronment and Development (DANCED).

The purpose of the project is to develop and implement an Environmental

Management System (EMS) for the City of Kuching within two areas of con-

cerns; namely river water quality and waste management.

The project has elaborated a generic model for a coherent EMS, which will

form the basis for developing a concrete EMS, adapted to the local Kuching

context.

An important part of the SUD Project is the elaboration of a baseline study on

river quality and river quality management of Sg. Sarawak and its tributaries.

The baseline study is carried out as a first step in the implementation of the

concrete Environmental Management System for the River Quality for the

Kuching City. The objective of the baseline study is to be able to set realistic

goals and indicators for the future river quality.

The Environmental Management Team (EMT) of the SUD Project has carried

out a process of selecting preliminary goals, targets and indicators for the se-

lected areas of concern. The EMT consists of representatives for the core agen-

cies dealing with aspects of Environmental Management for Kuching. The se-

lected goals, targets and indicators have been reported in the SUD report “Pre-

liminary Goals, Targets and Indicators for sustainable Urban Development in

Kuching, Sarawak”(SUD-02-03/SUD-021-07).

The preliminary indicators have constituted the starting point for elaborating

the baseline study.

A survey of existing and lacking data related to the selected indicators has been

carried out to facilitate the elaboration of the baseline study. The results of the

survey have been reported in the SUD report “Survey of Existing and Lacking

Data on the SUD Project Indicators” (SUD-02-05).



14

Based on this report, a data collection report was elaborated, specifying the

compilation of extisting data and supplementary field studies in and elaboration

of existing data (SUD report. River Quality Baseline Study. Data Collection

(SUD-02-10)).

A pilot study has been carried out for one of the Sg. Sarawak tributary Sg. Bin-

tangor catchment area. The study aimed at gaining experience in getting and

accessing relevant data from field studies and public files (SUD-02-09).

2.2 River Quality Baseline Study

The baseline study focuses on the selected preliminary indicators and the nec-

essary background data (physical-, ecological- and social data etc.) to identify

relations between sources and levels of deterioration of the environment. The

indicators include:

State indicators (water quality, quality of sediments, concentration of pol-

lutants in aquatic organisms and ecosystem parameters);

Load indicators (discharge from point and non-point sources); and

Effort indicators (measures taken by the authorities to affect the constrains

to the environment (e.g. inspection, enforcement) and the outcomes of the

measures (performance)).

The preliminary indicators are presented in Table 2.1.

Table 2.1 Preliminary indicators for river quality (from “Preliminary goals,

targets and indicators for sustainable urban development in Kuching, Sara-

wak (SUD report No SUD-02-03, SUD-02-07).

Parameters

State indicators Water quality pH, Dissolved oxygen, Biological oxy-

gen demand (BOD), Chemical oxygen

demand (COD), Total Suspended Sol-

ids (TSS), Ammoniacal nitrogen (NH4-

N), Nitrates, Phosphorous, Oil and

grease, Hg, Pb, As, Zn, Cd, Cr, Cu, Fe,

Ni, Cyanide, Mn, Polyaromatic Hydro-

carbons (PAH), Total Petroleum Hy-

drocarbon (TPH),Faecal and total coli-

forms

Sediment pH, Ammoniacal nitrogen (NH4-N),

Nitrates, Phosphorous, Oil and grease,

Hg, Pb, As, Zn, Cd, Cr, Cu, Fe, Ni,

Cyanide, Mn, Polyaromatic Hydrocar-

bons (PAH), Total Petroleum Hydro-

carbon (TPH), Pesticides.



15

Table 2.1 (continued)

Parameters

State indicators Pollutants in aquatic

organisms

Concentration of contaminant XX and

YY in aquatic organisms (mussels)

Ecological parameters 1) Diversity index

2) Species of fish of yy family

3) Species of invertebrates of zz fam-

ily.

Aesthetics 1) Level of smell by using standard

method.

2) Estimated weight of floatables col-

lected from Sarawak River

Load/effort indica-

tors

Households 1) Number of households

with/without septic tanks or other

treatment facilities treating sewage

to standard X (Equivalent or better

than standard B)

2) Type of septic tanks or treatment

facility (efficiency)

3) The concentration of pH, TSS,

Ammoniacal nitrogen, phospho-

rous, BOD,COD and E. Coli in

treated effluent from households

not exceeding xx based on labora-

tory analyses

Agriculture 1) Total number of pig farms

2) No of large pig farms with efficient

waste treatment system

3) Volume of discharge and SPP at

large piggeries. The discharge of

pH, TSS, Ammoniacal Nitrogen,

Phosphorous, BOD and COD in

discharge

4) Yearly survey of agricultural plan-

tations on the use of agrochemical

xx

5) Concentration of agrochemical xx

in mainstreams draining planta-

tions (upstream and downstream)

6) Yearly inspection of extent of

buffer zones around plantations



16


Parameters

Load/effort indica-

tors

Food outlets 1) Total number of food outlets

2) Number of food outlets having

efficient waste treatment facilities

treating wastewater to level X

(yearly inspection)

3) Concentration of oil and grease and

total suspended solids in wastewa-

ter based on laboratory analysis.

Large Scale industries

(LSI) and Small Me-

dium Industries (SMI)

1) Number of LSI and SMIs having

efficient wastewater treatment sys-

tem based on yearly inspection

2) Concentration of xx and yy in

treated effluent based on laboratory

analysis

River Vessels 1) Load of paint residue discharged to

Sg. Sarawak by inspection of ship

repair

2) Concentration of organo-tin in

mussels

3) Number of oil spill incidents re-

corded

The River Quality Baseline study is reported in three volumes:

Volume 1: River Quality Baseline Study. Main Report. Existing River

Quality, Pollution Sources and Environmental Management of Sg. Sarawak;

Volume 2: River Quality Baseline Study. Mapping of Pollution Sources and

Estimation of Pollution Load to Sg. Sarawak; and

Volume 3: River Quality Baseline Study. Field Studies of Sediment Con-

tamination and Benthic Invertebrate Fauna in Sg. Sarawak.

Volume 1 of the river quality baseline study report is structured as follows:

Section 3 briefly outlines the data collection;

Section 4 provides general background information, which is relevant for

the interpretation of the selected indicators for river quality. The section de-

scribes the physical background conditions (i.e. river catchment characteris-

tics, climate, geology, hydrography and riverbed sediments). The river eco-

system in terms of vegetation, benthic invertebrate fauna and fish fauna is

also described. Landuse in the catchment area for Sg. Sarawak and tributar-

ies is described as well. The relevant institutions and the legal measures to

administer the river quality are also briefly outlined;



17

Section 5 describes the present river quality in terms of surface water qual-

ity, sediment quality, aesthetics and concentrations of pollutants in organ-

isms as well as ecosystem impacts. The description is focused on the se-

lected preliminary indicators for river quality;

Section 6 outlines the sources of pollution and provides estimates of pollu-

tion loads from different sources in the sub-catchment areas for Sg. Sara-

wak, which are situated in Kuching City. Control and enforcement meas-

ures taken by the authorities to mitigate impacts on the environment are de-

scribed as well. Other sources deteriorate river quality, including the effect

of the downstream barrage of Kuching are also outlined.

Section 7 is the discussion and conclusion section. The section provides:

1. Characterisations of the degree of pollution of Sg. Sarawak;

2. Identification of major sources of river pollution and the relative contri-

bution to pollution of different sources;

3. Assessment of the existing technical measures to reduce pollution load;

4. Evaluation of the existing control and enforcement measures to manage

river quality; and

5. Assessment of the relevance of preliminary indicators and recommen-

dations for indicators to be included in the EMS.



18

3 Data Compilation

The baseline study is based on the existing data provided by agencies and local

authorities, and supplementary field and desk studies.

3.1 Compilation of Existing Data

Existing data were compiled and provided by the following aencies and Local

Councils:

National Resources and Environmental Board (NREB);

Department of Irrigation and Drainage (DID);

Department of environment (DOE);

Kuching North City Hall (DBKU);

Kuching City South Council (MBKS);

Padawan Municipal Council (MPP);

Land and Survey Department (L&S);

State Health Department (SHD);

Sarawak River Board (SRB);

Department of Public Works (JKR);

Kuching Barrage Management Sdn Bhd (KMB);

Kuching Water Board (KWB);

State Planning Unit (SPU);

Ministry of Industrial Development (MID); and

University of Malaysia Sarawak (UNIMAS).



19

Details of the compilation are elaborated in the SUD report of “River Quality

Baseline Study - Data Collection.” (SUD-02-10) A list of the compiled data is

presented in section 8.

3.2 Supplementary Field and Desk Studies

During the initial preparation of the baseline study, the following types of data

were identified as lacking and imperative for the baseline study:

Point Source/Pollution load inventory;

Biological/Ecosystem indicators; and

Sediment data.

The following field and desk studies were therefore conducted:

Mapping and enumeration of different pollution sources, measurements of

discharge of pollutants from households, food outlets (markets, restaurants

etc.) and industries for the estimation of pollution loads from different

sources;

Field investigations of sediment contamination; and

Field study of benthic fauna.

Details on the methods applied for the estimation of pollution loads is presented

in the Volume 2 of the River Quality Study. The methods applied for the sedi-

ment and benthos studies are outlined in the Volume 3.

3.3 Assessment of Collected Data

The compiled data and the supplementary field studies generally provide an

adequate basis for the elaboration of the baseline study. However, additional

data on enforcement measures and other effort indicators needs to be compiled

to allow proper assessment. In addition, there are some data, which were identi-

fied as relevant but not collected due to various constraints such as:

Technical constraints, which include:

- Lack of standardising of data

- Lack of standardised data registration forms

- Technical procedures

- Lack of computerising of files

Institutional constraints, which include:



20

- Classified data

- Possessiveness to data

- Competencies and capacities

In the next phase of the SUD Project measures for overcoming some of these

constraints will be prepared and specified, mainly standardising, registration

forms, administrative procedures and computerising of files.



21

4 Background Conditions

4.1 River and Catchment areas

Sg. Sarawak has two principal tributaries: Sg. Sarawak Kiri and Sg. Sarawak

Kanan, rising in the mountain ranges to the south of Kuching at the border of

Indonesia. The two tributaries meet near Batu Kitang, some 34 km upstream of

Kuching. From Batu Kitang, the mainstream Sg. Sarawak meanders across a

wide coastal flood plain and traverse Kuching. Downstream of Pending, the

industrial area in the eastern part of Kuching, Sg. Sarawak confluence with Sg.

Kuap and further downstream by Loba Batu Belat before discharging to the

South China Sea at Muara Tebas (Fig. 4.1).

In Kuching City, several small tributaries‟ discharges to Sg. Sarawak include

Sg. Maong, Sg. Bintangor, Sg. Padungan Sg. Sekama, Sg. Bintawa and Sg.

Biawak. Fig 4.2 shows the location of the tributaries in Kuching.

A total of 21 drainage sub-catchment areas in Kuching are discharging to Sg.

Sarawak on the stretch of the river from Sg. Maong to the Biawak causeway,

east of Pending. The locations of these sub-catchment areas are indicated on

Fig 4.3.

The remaining part of the city, including the Sama Jaya Free Industrial Zone

drains into Sg. Kuap, mainly via Sg. Tabuan.

In 1997 a gated barrage was constructed through the Sejingkat Isthmus (Fig.

4.2) and the river was blocked by causeways at Jalan Keruing and Jalan Bako

in order to regulate the tidal influence on the river.



22

Figure 4.1. Sg. Sarawak and its main tributaries.



23

Figure 4.2. Tributaries of Sg. Sarawak in the Kuching City.



24

Figure 4.3. Sub-catchment areas for tributaries and drains in Kuching discharging to Sg. Sarawak along the stretch from (and including) Sg.

Maong to the causeway east of Pending.



25

4.2 Physical Background Conditions

4.2.1 Climate

The climate in the catchment area of Sg. Sarawak is governed by the movement

of the Inter-Tropical Convergence Zone and the associated movement of the

warm air with the monsoons.

The catchment area has high rainfall. The annual rainfall for Kuching varies

between 3,000 and 5,000 mm. The wettest season is during the Northeast mon-

soon from November to March, with a peak rainfall in December to January

typically higher than 400 mm per month.

The minimum rainfall occurs in June and July. From April to July the mean

monthly rainfall is in the range of 200 to 300 mm. The mean relative humidity

is 85% with a maximum peak observed in December – March and a minimum

peak occurring during the period of lowest rainfall in June – July.

The temperature in the area ranges from about 220C to 340C. The warmest pe-

riod is April to June and the lowest temperatures are encountered during the

months from December to February (Meteorological Services Department

Kuching, 2000).

4.2.2 Geology

The Sg. Sarawak river basin is geologically made up of rocks of Palaeozoic and

Early Mesozoic ages (Annual Report Geological Survey of Malaysia, 1980).

The oldest rocks are considered to be the pre-Upper Carboniferous schist and

phyllite. Intrusive granite rocks are also common. The Sg. Sarawak delta depo-

sition north of Kuching in a marine trough occurred throughout Jurassic giving

rise to a sequence of predominantly argillaceous rocks with subordinate arena-

ceous rocks, chert, conglomerate and boulder slate and few lenses of conglom-

erate and limestone.

Sedimentary rocks of Sg. Sarawak Kiri are mainly acid igneous and metamor-

phic. Limestone, shale and mudstone with thin beds of siltstone and fin-grained

sandstone are common rock types of Sg. Sarawak Kanan (DID, 1988).

The soils of Sg. Sarawak Kiri and Sg. Sarawak Kanan are mainly composed of

recent alluvial and red yellow podzolic soils. Along the river valley, there are

recent alluvial soils with generally shallow to deep, yellow to red loamy sands

to clays on sedimentary, acid igneous and metamorphic rocks. To the north of

the Sg. Sarawak Kanan catchment, patches of hard limestone can be found,

while grey white podzolic soils are prominent in the south.



26

4.2.3 Hydrography

The upper reaches of Sg. Sarawak Kiri and Sg. Sarawak Kanan are narrow and

shallow. They are situated in steep terrain with gradients in excess of 1 % and

are therefore fast flowing.

Downstream of the confluence of Sg. Sarawak Kiri and Sg. Sarawak Kanan

below Batu Kitang and down to the sea, the river flows through a flat plain and

is becoming gradually wider and the current speed decreases.

Before the establishment of the barrage, the river was strongly influenced by

the tide and intruding saltwater. The tidal influences propagated as far as Buso

at Sg. Sarawak Kanan and Sebua at Sarawak Kiri, some 60 km from the estuary

mouth.

After the establishment of the barrage, the tidal influences and saltwater intru-

sions have been significantly reduced and a relatively stable water level has

been established. The barrage has also reduced the river flow velocities. The

reduced flushing effect of the tide and the reduced flow velocities have in-

creased sedimentation of suspended matter.

Today inflow of saltwater takes place when the barrage is opened for flushing

every second weekday in contrast to the pre-barrage period when intrusion of

saltwater took place twice a day.

The barrage is opened for flushing in order to prevent oxygen depletion in im-

poundments in front of the barrage and to flush out organic matter accumulated

in the sediment.

4.2.4 Riverbed Sediments

The sediments in the narrow, fast flowing upper reaches of Sg. Sarawak Kiri

and Sg. Sarawak Kanan mainly consists of gravel (Table 4.1).

Downstream of the confluence, where the current speed decreases, the riverbed

sediments are mainly composed of fine-grained silt and clay (Table 4.1).

The sand contents increase markedly in the Pending area, however, the sedi-

ments become silty again downstream of the barrage. The predominance of

sand off Pending is probably an effect of the flushing procedure at the barrage.

During flushing, the fine-grained particles of the sediment are suspended and

transported downstream of the barrage where they resettle. This is supported by

the fact that samples collected at Pending before the construction of the barrage

had a silt content of 70%. After the construction of the barrage, the silt content

in the Pending area decreased to 24% and the sand content increased to 76%

(Table 4.1, Fig 4.4).



27

Table 4.1 Grain Size Distribution of River Bed Sediments.

Location Gravel

(%)

Sand

(%)

Silt (%) Clay (%) Refer-

ence

Upper reaches of Sg. Sarawak Kiri 96 4 0 0 1

Upper reaches of Sg. Sarawak Kanan 97 3 0 0 1

Sg. Sarawak main

At Batu Kawa Bridge 2 20 63 15 1

Upstream confluence Sg. Maong 0 24 68 8 2

Downstream confluence Sg. Maong 0 30 64 23 2

At Satok Bridge (pre-barrage) 5 95 0 0 1

At Satok Bridge (post-barrage) 0 20 53 27 2

Confluence Sg. Bintangor 0 4 59 37 2

At Holiday Inn (pre-barrage) 2 98 0 0 1

At Holiday Inn (post-barrage) 0 22 56 22 2

Off Kuching Port Authority 0 25 49 26 2

Downstream confluence Sg. Bintawa 0 52 37 11 2

At Pending (pre-barrage) 0 19 70 11 1

At Pending (post barrage) 0 76 24 0 2

Downstream of Barrage 0 22 72 0 2

Tributaries

Sg. Maong (tributary of Sg. Sarawak) 0 20 56 24 1

Ref 1: “Water Quality and Sediment Monitoring for Sg. Sarawak Flood Mitigation Options

Study” as prepared by Chemsain Konsultant Sdn Bhd for Jurutera Jasa Sdn Bhd.

Ref 2: SUD sediment study November 2000. Reported in Vol 3 of the River Baseline Study

Figure 4.4. Composition of sediments in Sg. Sarawak at Pending before and

after the establishment of the barrage. Percentage of sand, silt and clay frac-

tions.

Hydrographic Section in Marine Department has carried out a survey on sedi-

mentation for SRB. This study showed a slight increase of sedimentation rates

after two years of operation of the barrage, due to the reduced river flow veloci-

ties. Samples collected at the Satok Bridge and at Holiday Inn before the estab-

0

10

20

30

40

50

60

70

80

before barrage after barrage

%

% sand % silt % clay



28

lishment of the Barrage, were much sandier compared to samples collected af-

ter (Table 4.1, Fig 4.5). This may reflect the increased sedimentation rate due to

the barrage, but may of course also simply be due to the difference in sampling

locations.

Figure 4.5. Composition of sediments in Sg. Sarawak at Satok Bridge and

Holiday inn before and after the establishment of the barrage. Percentage of

sand silt and clay fractions.

4.3 River Ecosystem

4.3.1 Riverbank Vegetation

Sg. Sarawak Kiri and Sg. Sarawak Kanan flow through heavily vegetated pri-

mary and secondary rainforest in varying stages of succession that grows close

to the waters edge.

The vegetation changes below Batu Kitang, where the two tributaries meet.

Wide beaches with reeds are encountered downstream of Batu Kitang. This is a

result of the slowing down of the river flow rate.

The vegetation along the river between Batu Kawa and the barrage is mainly

mangrove- and nipah forest. Mangroves and nipah forests are encountered in

tidal areas with fluctuating salinity. There is a concern that the decrease in sa-

linity due to the barrage may impact the mangrove trees and nipah palms.

4.3.2 Aquatic Vegetation

Water hyacinth (Eichhornia crassipes) is abundant particularly at the conflu-

ence of feeder streams, channels and riverbank settlements where the concen-

tration of nutrients is high. Explosive growth of water hyacinth is associated

with increased discharge of nutrients in slow flowing waters. The establishment

of the barrage resulting in slower water flow and reduced water exchange may

cause rapid proliferation of water hyacinth especially in areas with high nutrient

0

20

40

60

80

100

120

Satok before Holiday inn before Satok after Holiday inn after

%

%gravel % sand % silt % clay



29

load. Reduction of the present sewage/nutrient discharge to the river will re-

duce the risk of water hyacinth growth.

4.3.3 Benthic Invertebrates

The SUD Project carried out a study of benthic invertebrates in Sg. Sarawak

from upstream of Sg. Maong to downstream of the Barrage in November 2000.

The study showed that oligochaete worms dominate the fauna in Sg. Sarawak

upstream of the barrage. Tubificidae are the most common, with Tubifex occur-

ring as the most common genus. Downstream of the barrage, oligochates were

absent and marine molluscs dominate the fauna. The study is further discussed

in section 5.5 in this volume and in the Volume 3 of the Baseline Study Report.

A study carried out in 1995-1996 (KTA, 1997) indicated the presence of a large

stock of the giant freshwater prawn (Macrobrachium rosenbergii) in the river

from the Kuching area to the lower reaches of Sg. Sarawak Kiri and Sg. Sara-

wak Kanan. The giant freshwater prawn migrates downstream to spawn in

brackish water. The installation of the barrage may have reduced the stock of

the prawn in the river because the barrage acts as a barrier for the movement of

sexually mature indivuduals to the brackish water downstream for spawning

activities and the movement of juvenile stages upstream. However, the barrage

does not completely block the migration of prawns as it is opened every second

weekday. A interview with a fisherman in connection with the sediment and

benthos studies carried out by the SUD Project in November 2000 indicated

that Macrobrachium rosenbergii were often caught at the confluence of Sg.

Bintangor and Sg. Sarawak.

4.3.4 Fish

A study of the composition of the fish fauna was undertaken prior to the estab-

lishment of the barrage. The study was carried out in the main river of Sg. Sa-

rawak, Sg. Sarawak Kiri and Sg. Sarawak Kanan during the period from May

1995 to February 1996 (KTA, 1997).

Table 4.2 and 4.3 show the fish families and species encountered in the three

sections of the river system. It is evident that the composition of the fish fauna

in the main river Sg. Sarawak is very different from the fauna in the upstream

tributaries, Sg. Sarawak Kiri and Sg. Sarawak Kanan. Fish fauna composition

changes gradually along the river due to changes in environmental conditions.

The most important being: depth and width of stream/river, current velocity,

riverbed substrate, turbidity, availability of preferred food and influence of

tide/salinity.

The upper reaches of Sg. Sarawak Kiri and Sg. Sarawak Kanan are narrow,

shallow, fast flowing and clear streams, which flow over gravel and rocky bot-

toms. Here species from the Balitoridae and Sisoridae families are dominant.

Fish from the Bagridae family are also common. Further downstream, species

from the Cyprinidae family gradually become dominant and at the confluence

of Sg. Sarawak Kiri and Sg. Sarawak Kanan, the fish Mystus sp. replaces the

Cyprinids.



30

Downstream of the confluence, the river flows through a flat plain and is be-

coming gradually wider. The current speed decreases, the waters are turbid and

the riverbed is silty. All these environmental changes affect the composition of

the fish fauna. In 1995-1996, this part of the river was tidally influenced with

intrusion of saltwater/brackish water twice a day. The fish fauna comprised

both freshwater and marine species. About 66% of the total numbers of species

caught were marine or brackish and the remaining 34% were freshwater spe-

cies. After the establishment of the barrage in 1997, the inflow of saltwater has

been reduced. Today, the inflow of saltwater takes place when the barrage is

opened for flushing every second weekday compared to the pre-barrage period

when intrusion of saltwater took place twice a day. The stocks of marine and

brackish water species in the lower reaches of Sg. Sarawak will therefore,

probably decrease due to the presence of the barrage.

Table 4.2 Number of species of different fish families caught in Sg. Sarawak,

Sg. Sarawak Kiri & Sg. Sarawak Kanan during the period May 1995-

February 1996.

Family Number of species

Sg. Sarawak Kiri

Number of species

Sg. Sarawak Kanan

Number of species Sg.

Sarawak Proper

Antennariidae 1

Anguillidae* 1

Ariidae* 3

Bagridae 3 3 2

Balitoridae 3 1

Carangidae* 1

Channidae 2 1

Clariidae 1

Cyprinidae 11 4 1

Dasyathidae 1

Eleotrididae* 3

Gobiidae* 2

Hemiraphidae 1 1

Lutjanidae* 1

Mastacembelidae 1 1 1

Mugilidae* 1

Ophicephalidae 1

Plotosidae 1

Polynemidae 1

Scianenida 3

Siluridae 1

Siganidae 1

Sisoridae 3 1

Tetradontidae 1 1 1

Toxotidae 1 1 1

*Anguillidae, Ariidae, Carangidae, Eleotridae, Gobiidae, Dermogenys sp. Mugilidae and Lutjanidae

are primarily marine or brackish water fish families that may swim upstream into fresh water (Ref. 2).



31

Table 4.3 List of species of fish caught in Sg. Sarawak, Sg. Sarawak Kiri and

Sg. Sarawak Kanan during the period May 1995-February 1996.

Family Species Sg. Sara-

wak Kiri

Sg. Sara-

wak

Kanan

Sg. Sara-

wak

Main

Antennariidae Antennarius sp X

Anguillidae* Anguilla sp. X

Ariidae* Arius bilineatus X

Arius maculatus X

Arius venosus X

Bagridae Leiocassius micropogon X X

Mystus sp. 1 X X X

Mystus sp. 2 X X X

Balitoridae Gastromyzon danumensis X X

Homaloptera nebulosa X

Nemachilus kapuaensis X

Carangidae* Caranx sp X

Channidae Chana lucius X X

Cyclocheiltichtys apogon X

Clariidae Clarias sp X

Cyprinidae Paracrossochiluys vittatus X X

Puntius binonatus X

Puntius brevis X

Punthius lateristriga X X

Punthius sealei X

Rasbora borneensis X X

Rasbora caudimaculata X

Rasbora sarawakensis X

Rasbora spilotaenia X

Rasbora sp. X X

Tor sp X X

Dasyathidae Himantura signifer X

Eleotrididae* Bunaka gyrinoides X

Oxyeleotris marmorata X

Eleotris sp. X

Gobiidae* Glossogobius sp X

Periohthalmus sp X

Hemiraphidae Dermogenys sp* X

Hemiraphodon sp X

Lutjanidae* Lutjanus johnii X

Mastacembelidae Mastacembelus sp. X X X

Mugilidae* Liza sp X

Ophicephalidae Ophicephalus sp X

Plotosidae Plotosus sp X

Polynemidae Eleutheronema tetradactylum X

Scianenida Boesemania microlepis X

Pana microdon X

Johnius coitor X



32


Family Species Sg. Sara-

wak Kiri

Sg. Sara-

wak

Kanan

Sg. Sara-

wak

Main

Siluridae Kryptoterus lais X

Siganidae Siganus vermiculatus X

Sisoridae Glyptothorax plathypogon X X

Glyptothorax platypogon-

oides

X

Glyptothorax major X

Tetradontidae Xenopterus sp X X X

Toxotidae Toxotes sp X X X

*Anguillidae, Ariidae, Carangidae, Eleotridae, Gobiidae, Dermogenys sp. Mugilidae and Lutjanidae

are primarily marine or brackish water fish families that may swim upstream into fresh water (Ref. 2).

4.4 Landuse

Kuching is the principal urban center at the Sg. Sarawak River system. There

are numerous smaller towns and villages in the river valleys upstream of

Kuching including Batu Kawa, Batu Kitang, Siniawan and Bau. River valleys

have been developed for agriculture and the river is used for transportation,

fishing and water extraction.

4.4.1 Urban Landuse

Kuching

Kuching is a quite large city with a population of about 450,000 according to

the recent population census.

Historically, the built-up area of the city was concentrated on the south bank of

the river. Apart from the village settlements along the river, the north bank was

largely undeveloped until the early 1970s when the major bridge crossing at

Satok and the new State legislative and administrative hub were constructed.

The development of the major government establishments therefore created the

growth impetus for the development „across river‟ called Petra Jaya, which had

continued to gain momentum with the road connection to the resort areas at

Santubong and Damai.

The landuse pattern of Kuching has been analysed in connection to the SUD

Project and comprised the landuse of the catchment areas discharging to Sg.

Sarawak.

The City‟s industrial zone is concentrated to the eastern sector at Pending (fig.

4.6). In addition, there is an industrial area southeast of the study area near Sg.

Kuap, the Sama Jaya Free Industrial Zone. There is also a smaller industry zone

at Demak Laut.



33

The Central Business Centre is located in the middle of the City where there are

also residential and institutions areas. Predominantly residential areas are lo-

cated to the south and west (Fig 4.6).

Industrial development has haphazardly proliferated into the Batu Kawa and

Batu Kitang areas in recent years, due to the lack of such sites in the existing

industrial zones and of their proximity to population areas. The establishments

include garage workshops, cement batching plants, warehouses, etc.

A number of major commercial centres are spread over the south bank. They

include the Sekama and the Kenyalang Park shopping centres in the eastern

sector and the Satok/Rubber Road, the Green Road and the Central

Park/Timberland commercial centres in the western sector. A major commer-

cial centre is also currently being constructed at Batu Kawa.

At the north bank, government establishment forms the core of the develop-

ment, and a new town centre named Medan Raya is currently being built in that

vicinity. There are also a number of institutional buildings located in the area,

including a private hospital, the State mosque and library. Residential devel-

opment is also rapidly being undertaken in Petra Jaya.

The landuse in Kuching is described in detail in terms of pollution sources in

Volume 2 of the River Baseline Study and in section 6 of this report.

Batu Kawa

Batu Kawa is a small bazaar, with only two rows of shophouses situated on the

left bank of Sg. Sarawak.

Batu Kitang

Batu Kitang is a small service centre, situated at the Jalan Batu Kitang/Sg. Sa-

rawak Kiri Bridge crossing near the Kuching Water Board water treatment

plant.

Siniawan

Siniawan is a small bazaar situated on the south bank of Sg. Sarawak Kanan

approximately mid-way between Kuching and Bau.

Bau

Bau is an urban centre situated some 30 km from Kuching along Sg. Sarawak

Kanan. It is the administrative centre of Bau district. The town was founded on

gold and antimony mining, an activity which has gradually declined.



34

Figure 4.6. Landuse of catchment areas in Kuching discharging to Sg. Sarawak



35

4.4.2 Agriculture

Around 70% of the catchment areas of the Sg. Sarawak system are used for ag-

riculture. The most significant farming activities are shifting cultivation, horti-

culture mixed farming and pig rearing. The importance of oil palm farming is

increasing.

Shifting cultivation

Shifting cultivation covers by far the largest area within the catchment area (i.e.

47%). Shifting cultivation in Sarawak is a hill-padi based cropping system,

which is practised by the indigenous people. Shifting cultivation is a slash-and-

burn cultivation system in which the use of the fields is rotated. There has been

a general decline in the cultivated area over the last decade due to the gradual

switch to cash crops.

Horticulture and mixed farming

Around 10% of the catchment area are utilised for horticulture and mixed farm-

ing. This settled form of agriculture involves a wide range of crops such as

vegetables, fruits, cocoa, rubber and pepper (Table 4.4). These crops are culti-

vated on a small holder basis on scattered individual farms. Most of the fruits

and vegetables are sold on the markets in Kuching City.

Table 4.4 Main vegetables and fruits grown in the catchment area.

Vegetables Leafy vegetables: Chai Sim, Kai Lan, Kang Kong, Bayam, Pak

Choi, Changkor Manis etc

Tubers: yam, sweet potato, Lobak, groundnuts

Fruity vegetables: Cucumber, long bean, french bean, ladies

fingers, chilli, angle luffa, bitter gourd, pumkin, white gourd,

winged bean

Fruit Durian, rambutan, mango, mangosteen, langsat, guava coconuts.

papaya, banana, guava, citrus and starfruit

Pig rearing

There are several large commercial pig farms in the catchment area. They are

located in the Batu Kawa, Batu Kitang, Semaba/Kung Phin, Siniawan/Tg.

Durian and Buso areas (Fig. 4.7). The farm size ranges from farms with 100

heads to sizeable commercial farms of 3500 heads (Table 4.5).

Table 4.5 Number and size of large commercial pig farms in the catchment

area.

Number of pigs Number of farms

100-500 8

500-1000 8

1000-2000 8

2000-3500 3



36

Oil palm

Oil palm plantation has recently been introduced into the study area. The oil

palms are grown on estates of 100 –1,000 ha. Significant development of oil

palm estates is expected to take place in the future.



37

Figure 4.7. Location of pig farms in the catchment areas of the Sg. Sarawak

system.



38

4.4.3 Fishery and Aquaculture

A study of the fishery in the river was carried out in 1995-1996 prior to the es-

tablishment of the barrage.

The lower sections of the river from the confluence of Sg. Sarawak Kiri and Sg.

Sarawak Kanan to the Pending area in Kuching was an important fishing

ground supporting a commercial fishery of some significance. In 1995-96, there

were some 15 full time fishermen and 30 part time fishermen. In addition, a

considerable leisure fishery was taking place especially in the weekends by up

to 100 people.

Although fishing takes place in Sg. Sarawak Kiri and Sg. Sarawak Kanan they

are not important fishing grounds and they do not support any commercial fish-

ing activities.

The fishery in the mainstream Sg. Sarawak was carried out by the use of gill

nets, hook and lines, long trap nets (belat), cast nets and scoop net.

Gill nets were mainly used from downstream of Holiday Inn to Pending Port.

Long trap nets (belat) were used upstream of Satok Bridge and cast nets and

hook lines were used throughout the whole stretch of the river.

The total annual revenue generated from Sg. Sarawak fishery between Pending

Port and the confluence Sg. Sarawak Kiri and Sg. Sarawak Kanan was esti-

mated at RM 275,000. The most common species caught were freshwater giant

prawns (Macrobrachium rosenbergii) and the fish species Mystus spp. and

Oxyeleotris marmorata.

Brackish fish species made up about 75 % of the number of fish species caught

in 1995-96. With the construction of the barrage, the number of brackish spe-

cies above the barrage is expected to decline significantly. So is the stock of

giant freshwater prawn, which spawns in brackish water (Cf. sections 4.3.2 and

4.3.3). It is not known to what extent the barrage has affected the fishery today,

but it will probably not be possible to sustain the 1995-96 level of fishing. A

fisherman interviewed in November 2000 indicated that freshwater giant

prawns are still often caught at the confluence of Sg. Bintangor and Sg. Sara-

wak, but only a thorough fishery investigation can elucidate the effects of the

barrage on the fishery.

There are no aquaculture activities in the Sg. Sarawak Proper. However, pond

culture is very common among farmers in the catchment area. In 1996, it was

estimated about 1,900 fishponds were operated by 1,200 farmers (Ref. 1). The

ponds were mainly located along the Bau Kawa/Bau-Lundu road, the Musi area

and in Bau. Most of the ponds are rainfed with no connection to the river.



39

4.4.4 Mining

There are gold, silver, mercury, antimony and kaolinitic clay deposits in the Sg.

Sarawak catchment area. Occurrences of copper, lead, zinc and iron have also

been noted but are not of great significance.

Most of the known mineral deposits are located in the Bau district. Since the

beginning of the last century gold and silver has been mined here. Previously

mercury and antimony was exploited as well. No mining activities take place

today.

4.4.5 Water Extraction

Approximately 95% of the water supplies for Kuching City are obtained from

Sg. Sarawak Kiri via Kuching Water Boards pumping station at Batu Kitang.

The river basin of Sg. Sarawak Kiri above this point has been gazetted as a wa-

ter catchment area to protect this important water resource.

4.5 River Quality Management in Kuching

Several agencies undertake and/or have a mandate to undertake separate func-

tions relevant to river water quality management. Below follow a brief descrip-

tion of the functions and related agencies. In Appendix 2, there is an overview

of the State administration, which is organised in a Chief Minister‟s Depart-

ment, 10 ministries and local authorities. In Appendix 3, there is a brief sum-

mary of relevant activities and mandates.

4.5.1 Goals Setting

With the recent amendment to the Natural Resources and Environment Ordi-

nance (NREO) in May 2001, the overall State‟s environmental management has

explicitly been delegated to the Natural Resources and Environment Board

(NREB). According to section 5m, the Board may set environmental quality

goals and determine and take the necessary measures for achieving such goals.

According to section 5c, this power includes issuing of directions or orders to

other environmental authorities.

The present baseline study is conducted as a precondition for determining the

future goals for river water quality. According to section 5n the NREB can di-

rect any environmental authority to undertake monitoring and reporting of envi-

ronmental quality. This power is required for procuring the comprehensive

baseline studies as well as for the continuous updating of the data for the peri-

odical environmental statements.

On a federal level the Environment Quality Act (EQA) delegates a broad man-

date to the Department of Environment (DOE) to recommend on environmental

policies to the Minister and to conduct environmental planning (section 3c&o).

According to section 51(ee), the Minister can issue regulations on ambient wa-

ter quality standards. Until now, no regulation has been issued but a set of “In-



40

terim National Water Quality Standards” (INWQS) has been prepared. State

goals will as, a minimum, have to conform to federal standards.

Other State‟s ordinances also include the aspect of river quality management.

According to the Water Ordinance (WO), issues on conservation, protection,

development and management of the water resources of the State are among the

duties and functions of the Water Resources Council.

Landuse related to riverbanks is regulated by Land and Survey Department

(L&S). Development of land is regulated by State Planning Authority (SPA).

Sarawak Rivers Board (SRB) has specific powers to regulate activities along

the banks of gazetted river (SRC 16 & 22).

4.5.2 Water Quality Monitoring and Reporting

It is the duty of DOE to produce a yearly report on the state of the environment

in Malaysia (EQA, section 3). This yearly report includes the status of the wa-

ter quality in the major Malaysian rivers. The information presented is based on

an overall index, calculated from 7 main water quality parameters.

NREB undertakes river monitoring of certain water quality parameters in the

main rivers.

Other State agencies carry out monitoring for specific purposes. There are no

explicit legal provisions regarding this monitoring. Monitorings are carried out

by SRB for river water quality, Public Works Department (JKR) and Kuching

Water Board (KWB) for drinking water quality. Drainage and Irrigation De-

partment (DID), JKR and Kuching Barrage Management carry out hydraulic

measurements to monitor flooding, drainage etc.

4.5.3 Regulatory Measures

A substantial number of agencies are involved in regulation of the discharge of

wastewater, sewage and solid waste to the river.

Standards for discharge to inland waters are generally issued by DOE accord-

ing to EQA section 21 and 51(ee). The present standards are issued as the 1979

Environmental Quality Sewage regulations. NREB can similarly regulate dis-

charge according to NREO 18(u&v).

Hazardous (scheduled) waste is separately regulated by the EQA.

Prior approval of activities, which may cause discharge to inland waters, is

conducted by several agencies.

Approval of EIAs for specific activities is conducted by DOE and NREB re-

spectively. The division of tasks is specified in the regulations. DOE generally

deals with industrial and infrastructural projects while NREB deals with lan-

duse projects.



41

Licensing of specific activities is conducted by:

DOE (Crude palm oil, raw natural rubber and activities discharging higher

concentrations of polluting substances than determined in the Environ-

mental Quality Sewage regulations);

Public Health Authorities and Local Authorities (markets, food outlets,

preparation and processing of food, hotels, petroleum storage);

Veterinary Health Authorities (abattoirs, meat processing, rearing of live-

stock);

Ministry of Agriculture (aquaculture); and

Land and Survey Department (mining, certain activities within prescribed

urban areas).

Permission from Sarawak Rivers Board (SRB) is required for discharge of ef-

fluents or sewage into navigable (gazetted) rivers or into drains that discharge

into gazetted rivers (Sarawak Rivers Cleanliness bylaw (SRC) section 13).

Discharge of pollutants into inland waters is prohibited according to EQ Sew-

age Regulation (Section 6), NREO (section 30a), the Local Authorities Ordi-

nance (section 117), Local Authorities (Cleanliness) By-law (section 18) and

Sarawak Rivers Ordinance (gazetted rivers) (Section 33). Specific prohibitions

are issued according to the Water Ordinance (WO) for designated water catch-

ment areas.

Orders or directives relating to discharge into inland waters may be issued by

DOE (EQA section 31), NREB (NREO 10(j)), Local Authorities (LAO section

112 (nuisances)) and SRB (SRC section 22 (gazetted rivers)).

4.5.4 Wastewater and Sewage Systems

In general, the local authorities have an obligation to keep the area under their

jurisdiction clean and hygienic in accordance with the Local Authority Ordi-

nance (section 91). Section 104 and 105 give mandates to establish, maintain

and carry out sanitary services including removal or otherwise dealing with

night-soil and all kinds of effluent, and to issue relevant rules and by-laws.

Today, the public stormwater drains serve as the main sewage system. Con-

struction and maintenance of public drains and sewage systems are included in

the powers delegated to the Local Authorities (LAO 132 & 138). The works are

typically carried out by JKR on behalf of the Local Councils. DID have been

increasingly involved in planning and implementing the major drainage sys-

tems (trunk systems) because of the accelerated urbanisation of the State. The

involvement is not based on specific legal provisions. Drainage integrated in

development projects for new areas are conducted by the developer and handed

over to the Local Councils at project completion. However, the Local Councils

have no obligation to accept such hand over.

Construction and operation of sewage treatment (sewage farms and sewage

disposals works) are similarly delegated to the local authorities (LAO 134).



42

However, State major development projects typically derive from the State

Planning Unit (SPU) as special projects. Future centralised sewage treatment

for Kuching is in accordance with this expected to be initiated by SPU.

Every Government agencies and Local Authorities shall submit projects for the

protection and the environment to the NREB for its recommendation before

submitting to the State Parliament for approval (NREO 9).

Establishment of sewers or drains carrying sewage or effluents to be discharged

into a gazetted river requires a permission from SRB (SRC 9). In addition, SRB

has specific powers to order dismantling, demolishing or alteration of the posi-

tion of drains and sewers to avoid discharge of effluents and sewage into gazet-

ted rivers (SRC 8 & 10). Similarly SRB has specific powers to require the

treatment of the effluents (SRC 10).



43

5 River Quality

Sg. Sarawak and its tributaries in Kuching are receiving sewage and wastewater

from a wide variety of sources in Kuching including households, food outlets

(markets, restaurants etc.) and industries. In addition, Sg. Sarawak receives pol-

lutants from agriculture, mining and landclearing activities as well as sewage

from cities and villages upstream of Kuching. The sources of pollution and pol-

lution loads from different sources are described in section 6.

5.1 Potential Impacts of the Discharge of Wastewater

Sewage and wastewater deteriorate the water quality of the tributaries and the

main river, the extent of deterioration depending on the amount of sewage and

the water exchange.

The potential impacts from sewage discharge can be grouped into:

Impacts of organic matter and nutrients;

Impacts due to pathogenic microorganisms; and

Impacts of toxic substances.

Organic matter

The impacts of the discharge of organic matter in sewage are basically caused

by the microbial degradation of organic compounds. In a river, some significant

effects are:

After discharge, microorganisms (bacteria, fungi and ciliates) on the river-

bed and other surfaces degrade the organic matter in the sewage, consum-

ing oxygen during the process;

The Biological Oxygen Demand (BOD), which is a measure of the biode-

gradable organic matter in the water, increases dramatically at the outlet,

but succeedingly the BOD decreases due to sedimentation of particulate

matter and to degradation of dissolved organic matter (Fig 5.1 A);

The oxygen consumption of the sediment increases immediately down-

stream of the outlet due to the microbiological activity and the concentra-



44

tion of oxygen in the sediment and water decrease. However, the oxygen

consumption of the sediment decrease further downstream concurrently

with the decrease of organic matter and the concentration of oxygen in-

creases again (Fig 5.1A);

The degradation of organic matter result in the release of ammonium

(NH4+) and phosphate (PO4

3-). The ammonium is nitrified by microorgan-

isms to NO3- consuming oxygen in the process (Fig 5.1 B);

These processes affect the invertebrate fauna in the river due to changes in

the supply of food, structure of sediment and concentration of oxygen. Low

oxygen levels and high organic content of the sediment favours organisms

which can tolerate low oxygen concentrations and which are deposit feed-

ers subsiding on organic detritus and its associated microflora. When dis-

solved oxygen reaches very low level, the organisms die.

The degradation of organic matter may also cause offensive odours. In

oxygen depleted environments, extremely malodorous compounds like

methane and hydrogensulphide is thus released.

Pathogenic organisms

Sewage may contain pathogens (disease-causing organisms) such as hepatitis

B, cholera, and typhoid. Faecal coliforms, which are bacteria found in the intes-

tinal tracts of mammals, including humans, are measured as an indicator of the

extent of contamination by pathogens. Most faecal coliforms are not hazardous

to humans; however, they provide an indication of the amount of faecal matter

present, which may be contaminated with other pathogens.

Toxic substances

Hundreds of potentially toxic substances are found in sewage effluent. These

include metals (such as mercury, arsenic, lead, chromium, copper, cadmium,

and silver), hydrocarbons, synthetic organic chemicals, and chlorine.

The contaminants are continuously accumulated in the sediments of the river.

They are generally adhered to fine-grained particles in the sewage and settled

with sediments on the riverbed. Some of these contaminants can remain in the

environment for a long time and many of them cannot be degraded (such as

heavy metals).

Some metals and organic compounds may accumulate in organisms and are

passed up the food chain to predator species. This process, known as biomag-

nification or bioaccumulation, is one of the ways that contaminants in sewage

effluent may affect people.



45

Figure 5.1. The effects on the discharge of sewage in a river in terms of con-

centrations of oxygen, BOD, NH4+ and NO3

- in the water column with increas-

ing distance from the outlet.



46

5.2 Surface Water Quality

The assessment of the surface water quality of Sg. Sarawak focuses on parame-

ters, which have been chosen as preliminary indicators for water quality in the

EMS for Kuching i.e.:

pH, DO, BOD, COD, Total Suspended Solids, Oil & Grease;

Nutrients (Ammoniacal Nitrogen, Nitrate, Total Nitrogen, Phosphorus);

Heavy Metals (Hg, Pb, As, Zn, Cd, Cr, Cu, Fe, Ni, CN, Mn); and

Coliform Counts.

Evaluation of the present water quality is based on water quality data collected

by NREB, KWB and UNIMAS in year 1999 and 2000. Descriptions of changes

in water quality since 1984 are based on data from DOE.

For the assessment of the present water quality the selected monitoring loca-

tions are grouped in various zones as follows (Cf. Table 5.1):

Zone A, comprising sampling sites on Sg. Sarawak Kanan;

Zone B, comprising sampling sites on Sg. Sarawak Kiri;

Zone C, comprising sampling sites on Sg. Sarawak Proper from Batu Kawa

to upstream of Satok Bridge;

Zone D, comprising sampling sites on Sg. Sarawak Proper from Sg. Satok

Bridge to downstream of Barrage;

Zone E, comprising sampling sites on comprising sampling sites on Sg.

Maong (Tributary discharging to Sg. Sarawak);

Zone F, comprising sampling sites on Sg. Bintangor (Tributary discharging

to Sg. Sarawak);

Zone G, comprising sampling sites on Sg. Padungan (Tributary discharging

to Sg. Sarawak);

Zone H, comprising sampling sites on Sg. Sekama (Tributary discharging to

Sg. Sarawak); and

Zone I, comprising sampling sites on Sg. Tabuan (Tributary discharging to

Sg. Kuap).



47

Table 5.1 provides an overview of assessment zones and data sources and Fig-

ure 5.2 indicates the location of monitoring sites in the City of Kuching.



48

Table 5.1 Overview of data and monitoring sites used in the assessment of the

present water quality. Numbers in parentheses refer to station numbers. The

locations of these stations are presented in Fig. 5.2.

Selected Monitoring Location Sources

Zone A

SMK Bau

Wind Cave

Bau Water Intake Point

(a) NREB‟s River Watch Monitoring Programme: Water

Quality Data for Southern Region

May – December 1999

January – August 2000

(b) Kuching Water Board: Raw Water Quality Report for

the year 1999 and 2000 (up to Oct.)

Zone B

Kpg. Bukit Panchor

Batu Kitang Intake Point

(c) NREB‟s River Watch Monitoring Programme: Water


January – December 1999


(d) Kuching Water Board: Raw Water Quality Report for

the year 1998, 1999 and 2000 (up to Oct.)

Zone C

Kampung Batu Kawa

Batu Kawa Bridge

(e) Kuching Water Board Raw Water Quality Reports for

the years 1998, 1999 and 2000.

Zone D

Under Satok Bridge (W2)

Near Holiday Inn Discharge

Point (W3)

Bako Causeway (W9)

Upstream Barrage (W7)

Downstream of Barrage (W8)

(f) NREB‟s River Watch Monitoring Programme: Water


January – November 1999

January – August 2000

Zone E

Sg. Maong (N1)

Sg. Maong (N2)

Sg. Maong (N3)

Sg. Maong (N4)

(g) NREB‟s River Watch Monitoring Programme: Water


January – November 1999


Zone F

Sg. Bintangor (W2)

h) NREB‟s River Watch Monitoring Programme: Water

Quality Data for Southern Region. January – September

2000

Zone G

Sg. Padungan (W4)

i) NREB‟s River Watch Monitoring Programme: Water

Quality Data for Southern Region. January – September

2000

Zone H

Sg. Sekama (W5)

j) NREB‟s River Watch Monitoring Programme: Water


January – September 2000

Zone I

Sg. Tabuan (St 1-St 6)

k) UNIMAS study. Sampling in September and December

1999



49

Figure 5.2. Water Quality Monitoring Sites in the City of Kuching.



50

5.2.1 General Overview

The water quality data from NREBs‟ River watch programme for year 2000 is

used to compare the degree of pollution of different stretches of Sg. Sarawak

and tributaries. For this year, there are simultaneous monthly measurements

from Sg. Sarawak Kiri, Sg. Sarawak Kanan, Sg. Sarawak Proper, Sg. Maong,

Sg. Bintangor, Sg. Padungan and Sg. Sekama, which are not available from

previous years.

Organic matter, nutrients and oxygen

The concentrations of BOD and ammoniacal nitrogen are low in Sg. Sarawak

Kiri and Kanan. Correspondingly, the oxygen conditions are good with mean

concentrations of oxygen of more than 5 mg/l (Figure 5.3).

The concentrations of BOD and ammoniacal nitrogen are also low in the part of

Sg. Sarawak, which is facing Kuching. However, the concentration of oxygen

is significantly decreased compared to the zones upstream of Kuching. The

mean concentration is around 4 mg/l. Oxygen concentrations, which are below

4 mg/l may cause harmful effects on sensitive organisms in the river. The low

BOD values along this stretch of the river may not be literally taken as an indi-

cation of low organic loading in the river water. In a warm tropical climate

where biodegradation of organic material is rapid, low dissolved oxygen con-

centrations as those observed in the lower reaches of Sg. Sarawak are most

likely due to decomposition of the high loading of organic matter.

The tributaries situated in Kuching are extremely polluted with very high con-

centrations of BOD and ammoniacal nitrogen with very poor oxygen condi-

tions. In fact, concentrations below 2mg/l are consistently encountered. Very

few organisms can survive in such low concentrations of oxygen.

The poor water quality in the tributaries and Sg. Sarawak in Kuching is mainly

due to the discharge of untreated sewage from the drains in the city.



51

Figure 5.3. Mean concentration of Dissolved oxygen, BOD and ammoniacal

nitrogen (NH4-N) in 2000 in different zones of the Sg. Sarawak as defined

above. (Sg. Sarawak corresponds to Zone D: i.e.to the main stretch of Sg. Sa-

rawak Proper from Sg. Satok Bridge to downstream of Barrage.

Odours

The SUD Project has introduced an internationally recognised standard method

for the assessment of the intensity of smell in river and drain water in Kuching.

The method determines Threshold Odour Number (TON) by a panel of smell-

ers. The TON is defined as the number of dilutions of a water sample which is

necessary in order to obtain a mixture in which odour is just perceived with cer-

tainty by the panellists, i.e. the higher the threshold odour number the higher

intensity of smell. The method is described in SUD document SUD-02-29 “De-

termination of odour characterisation in water”.

Table 5.2 presents the results obtained during the introduction of the method. It

is evident that there is no or very little odour in Sg. Sarawak Proper. In contrast,

the waters in the tributaries Sg. Bintangor and Sg. Sekama are very smelly and

the drain water from the market at Petanak smell extremely strong.

0

1

2

3

4

5

6

7

8

9

10

Kiri Kana Sg Sarawak Sg Maong Sg Bintangor Sg Padungan Sg Sekama

DO

;BO

D m

g/l

0

0,5

1

1,5

2

2,5

3

3,5

4

NH

4 m

g/l

DO BOD NH4



52

Table 5.2 Results of testing of odours in river water. April and May

2001.Threshold odour number determined by a panel of smellers. For the

results indicated as <(less than) some of the panellists could not smell even

the most concentrated samples.

Sample point Result

Satok Bridge 2

Sg. Sarawak (middle) No odour

Sg. Sarawak (bank) 3

Sg. Maong <530

Sg. Bintangor 17

Sg. Bintangor 240

Pasar Petanak 560

Pasar Petanak 6200

Sg. Sekama <680

Bacteria

Sg. Sarawak is polluted significantly by faecal-derived coliform bacteria. The

waters, particularly along the part of the Sg. Sarawak Proper and the tributaries

in Kuching, have extremely high bacteria counts and the water pose a serious

health risk (Table 5.3).

Table 5.3 Mean bacterial counts in the different zones of the river in the year

2000.

Zone Mean conc. of Total

Coliform (MPN/100ml)

Mean conc. of Faecal coli-

forms (MPN/100ml)

Zone A Sg. Sarawak Kanan 9400 5100

Zone B Sg. Sarawak Kiri 11800 7500

Zone C (Batu Kawa to Satok bridge) 4300 -

Zone D (Satok to Barrage) > 16000 > 16000

Zone E (Sg. Maong) > 16000 > 16000

Zone F (Sg. Bintangor) > 16000 > 16000

Zone G (Sg. Padungan) > 16000 > 16000

Zone H (Sg. Sekama) > 16000 > 16000

Heavy metals and other hazardous pollutants

The levels of heavy metals in water are generally very low and below the detec-

tion limits, except for iron and manganese (Cf. Appendix 1). The levels of iron

and manganese is generally violated the Malaysian water quality standards (Cf.

below) at all monitoring stations in the Sg. Sarawak system.

The high iron and manganese concentrations are due to natural processes and

not primarily a result of human activities, although the discharge of wastewater

may contribute to increased levels. Results from 1999 indicate that the concen-

trations of iron in Sg. Sarawak Kiri are at the same level as those encountered



53

in the heavily polluted Sg. Maong and higher than the levels in Sg. Sarawak

main fronting Kuching (Zone D) (Table 5.4).

High background concentrations in surface water are common in tropical natu-

ral waters as iron is constantly leached from the iron-rich soil and rocky sub-

strates (Menon & Murtedza, 1999). Leaching of iron is particularly significant

in swampy areas such as peat and freshwater swamps, nipah forests and man-

groves, which are abundant in the Sg. Sarawak catchment area. The soils in

such areas are waterlogged and anaerobic. In the anaerobic, waterlogged soil,

the solubility of iron increases. Insoluble Fe+++ is reduced to soluble Fe++,

which is then transported via groundwater to the river. The solubility of man-

ganese increases in anaerobic swampy area in the same way as iron (Chapman,

1997).

The available data indicate that agrochemicals and pesticides are generally be-

low detection limits (Menon & Murtedza, 1999).

Table 5.4 Mean concentrations of iron in different zones of the river in the

year 1999. Wet season: Nov-Feb. Dry season: Mar-Oct. Data not available

for year 2000 and for Zone A and Zones F-H

Zone Mean concentration

wet season (mg/l)

Mean concentration

dry season (mg/l)

Zone B Sg. Sarawak Kiri 2.3 1.0

Zone C (Batu Kawa to Satok bridge) 0.7 0.8

Zone D (Satok to Barrage) 0.9 0.8

Zone E (Sg. Maong) 2.0 1.3

5.2.2 Water Quality Classification of Different Zones

The data have been compared to the Malaysian Interim National Water Quality

Standards (INWQS) in order to make a classification of the water quality of the

different zones of the river. The INWQS operates six classes of water quality:

Class I, representing water bodies of excellent quality, most suitable for

water extraction for human consumption. This type of water is typically en-

countered in uninhabited areas without antropogenic discharge. Very sensi-

tive aquatic species thrive in Class I waters;

Class IIA, representing water bodies of good quality. Most existing raw wa-

ter supply sources in Sarawak come under this category. Conventional low

cost treatment required;

Class IIB water, which is suitable for recreational use with body contact. If

used for water supply for human consumption, excessive treatment is re-

quired which incurs relatively high costs;



54

Class III, representing polluted water. The class is used primarily to protect

common and moderately tolerant aquatic species of economic value. Water

under this classification may be used for water supply with exten-

sive/advanced treatment;

Class IV, representing heavily polluted water which must only be used for

irrigation purposes; and

Class V, representing heavily polluted water, which must not even be used

for irrigation purposes.

The concentration limits for pollutants in the different classes of water quality

are stipulated in DOE, 1993. Selected values are presented in Table 5.5.

A classification according to the INWQS of the different zones of the Sg. Sa-

rawak system based on the 1999 and 2000 data is presented below.

Table 5.5 Selected water quality parameters used in the classification under

the DOE Interim National Water Quality Standards for Malaysia.

Parameters Class

I

Class

IIA

Class

IIB

Class

III

Class

IV

Class

V

NH4-N (mg/l) 0.1 0.3 0.3 0.9 2.7 >2.7

BOD (mg/l) 1 3 3 6 12 >12

COD (mg/l) 10 25 25 50 100 >100

DO (mg/l) 7 5-7 5-7 3-5 < 3 < 1

TSS (mg/l) 25 50 50 150 300 >300

Faecal Coliforms *

(counts/100ml)

10 100 400 5000

(20,000)

5000

(20,000)

Total Coliforms

(counts/100 ml)

100 5000 5000 50,000 50,000 >50,000

* Geometrical mean. Values in parentheses must not be exceeded

Zone A (Sg. Sarawak Kanan)

The data from Sg. Sarawak Kanan are summarised in Tables 1-2 in Appendix

1. Mean concentrations of selected parameters are presented in Table 5.6.

The water quality of Sg. Sarawak Kanan is quite good in terms of physico-

chemical parameters (DO, BOD, COD, TSS, Turbidity and Ammoniacal-

Nitrogen etc). In general, these parameters comply with Class IIA/IIB limits.

However, the water does not meet the class IIA/IIB standards for coliform bac-

teria, which is probably due to discharge of untreated domestic wastewater

from the riverine communities, including Bau and Siniawan areas.



55

Table 5.6 Mean concentrations of selected water quality parameters in Zone

A (Sg. Sarawak Kanan). Wet season: Nov-Feb. Dry season: Mar-Oct.

Parameter Wet Sea-

son 1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB

No samples 6 18 6 18

NH4-N (mg/l) 0.1 0.1 0.08 0.1 0.3

BOD (mg/l) <0.2 <0.2 0.52 0.6 3

COD (mg/l) 16.1 12.6 6.8 6.9 25

DO (mg/l) 6.0 4.8 6.0 6.1 5-7

TSS (mg/l) 29.3 22.1 24.0 13.2 50

Faecal coliforms

(counts /100ml)

6167 6239 3850 6528 400

Total coliforms

(counts/100ml)

10,500 10,183 9504 9339 5,000

Zone B (Sg. Sarawak Kiri)

The water quality of Sg. Sarawak Kiri is also generally good for most physical

chemical parameters, which conform to class IIA/ IIB standards (Tables 3 and 4

in Appendix 1 and Table 5.7).

However, TSS levels are relatively high. In 1999, the average levels recorded

during dry (87.1 mg/l) and wet seasons (82.7 mg/l) were almost the same. The

average TSS trends in year 2000 shows that the value was higher during wet

season 141.8 mg/l) compared to dry season (59.1 mg/l). This may due to sur-

face run-off during downpour. The values were higher than the Class IIB limits.

Land clearance, earthworks, shifting cultivation and logging activities at some

sections upstream could contribute to the high TSS values.

High levels of coliforms were also detected in Sg. Sarawak Kiri and the water

quality standards for class IIB was violated. Dwelling units with poor sanitation

facilities along the river are possible sources.


B (Sg. Sarawak Kiri). Wet season: Nov-Feb. Dry season: Mar-Oct.

Parameter Wet Sea-

son 1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB


NH4-N (mg/l) <0.1 <0.1 0.1 0.1 0.3

BOD (mg/l) <2.0 <2.0 0.4 0.8 3

COD (mg/l) 17.5 13.8 15.0 10.6 25

DO (mg/l) 5.3 4.5 5.7 5.4 5-7

TSS (mg/l) 82.7 87.1 141.8 59.1 50

Faecal coliforms

(counts /100ml)

4100 3974 5975 9010 400



56

Zone C (Sg. Sarawak Proper from Batu Kawa Bridge to upstream Satok

Bridge)

In general the water quality values in zone C complies with class IIA/IIB. The

average Total Coliform levels are however marginally higher than the Class IIB

limits (Table 5.8, Tables 5-6 in Appendix 1).


C (main Sg. Sarawak from Batu Kawa Bridge to upstream of Satok Bridge).

Wet season: Nov-Feb. Dry season: Mar-Oct.

Parameter Wet Season

1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB


NH4-N (mg/l) <0.1 <0.1 <0.1 <0.1 0.3

BOD (mg/l) <2.0 <2.0 <0.2 <0.2 3

COD (mg/l) 10.3 18.1 19.3 20.1 25

DO (mg/l) - - - - 5-7

TSS (mg/l) - - - - 50

Faecal coliforms

(counts/100ml)

- - - - 400

Total coliforms

(counts/100ml)

5400 6150 5400 3328 5,000

Zone D (Sg. Sarawak Proper from Satok Bridge to Downstream of

Barrage)

The water quality in Zone D can be classified as class III in terms of physico-

chemical parameters. This is mainly due to a relatively low level of oxygen and

elevated level of NH4-N. However, in terms of bacteriological parameters, the

water is only class V, due to very high levels of bacteria consistently exceeding

16,000 (Table 5.9 and Tables 7-8 in Appendix 1).


D (main Sg. Sarawak from Satok Bridge to Downstream of Barrage). Wet

season: Nov-Feb. Dry season: Mar-Oct.


1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB


NH4-N (mg/l) 0.9 1.5 0.1 0.3 0.3

BOD (mg/l) 1.1 1.2 0.4 1.2 3

COD (mg/l) 10.7 14.8 6.7 14.9 25

DO (mg/l) 4.3 4.1 6.9 3.8 5-7

TSS (mg/l) 25.3 27.8 43.7 73.5 50

Faecal coliforms

(counts/100ml)

>16,000 >16,000 >16,000 >16,000 400

Total coliforms

(counts/100ml)

>16,000 >16,000 >16,000 >16,000 5,000



57

Tributaries in Kuching

The water qualities in the tributaries Sg. Maong (Zone E), Sg. Bintangor (Zone

F) Sg. Padungan (Zone G), Sg. Sekama Zone (H) and Sg. Tabuan (Zone I) are

very poor and fall between class IV/V (Tables 5.10-5.14 and Tables 9-10 in

Appendix 1).


E (Sg. Maong). Wet season: Nov-Feb. Dry season: Mar-Oct.


1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB


NH4-N (mg/l) 2.2 4.6 2.0 4.7 0.3

BOD (mg/l) 9.6 11.9 3.6 6.0 3

COD (mg/l) 35.2 37.5 27.0 32.3 25

DO (mg/l) 1.3 1.4 2.6 0.8 5-7

TSS (mg/l) 15.6 17.5 12.0 27.8 50

Faecal coliforms

(counts/100ml)

>16,000 >16,000 >16,000 >16,000 400

Total coliforms

(counts/100ml)

>16,000 >16,000 >16,000 >16,000 5,000


F (Sg. Bintangor). Wet season: Nov-Feb. Dry season: Mar-Oct.


1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB

No samples - - 2 10

NH4-N (mg/l) - - 1.7 3.1 0.3

BOD (mg/l) - - 3.6 5.6 3

COD (mg/l) - - 11.4 25.4 25

DO (mg/l) - - 2.2 2.4 5-7

TSS (mg/l) - - 19.5 39.7 50

Faecal coliforms

(counts/100ml)

- - >16,000 >16,000 400

Total coliforms

(counts/100ml)

- - >16,000 >16,000 5,000



58


G (Sg. Padungan). Wet season: Nov-Feb. Dry season: Mar-Oct


1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB

No samples - - 2 10

NH4-N (mg/l) - - 4.2 3.2 0.3

BOD (mg/l) - - 3.9 5.8 3

COD (mg/l) - - 23.6 31.8 25

DO (mg/l) - - 1.9 2.2 5-7

TSS (mg/l) - - 24 46.6 50

Faecal coliforms

(MPN/100ml)

- - >16,000 >16,000 400

Total coliforms

(counts/100ml)

- - >16,000 >16,000 5,000


H (Sg.Sekama). Wet season: Nov-Feb. Dry season: Mar-Oct


1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB

No samples - - 2 10

NH4-N (mg/l) - - 1.2 2.2 0.3

BOD (mg/l) - - 3.1 4.5 3

COD (mg/l) - - 14.7 22.5 25

DO (mg/l) - - 3.3 2.9 5-7

TSS (mg/l) - - 44.5 39.6 50

Faecal coliforms

(counts/100ml)

- - >16,000 >16,000 400

Total coliforms

(counts/100ml)

- - >16,000 >16,000 5,000



59


I (Sg. Tabuan. Wet season: Nov-Feb. Dry season: Mar-Oct


1999

Dry Season

1999

Wet Season

2000

Dry Season

2000

INWQS

class IIB

No samples 54 54 - -

NH4-N (mg/l) 2.6 2.9 - - 0.3

BOD (mg/l) 19.9 14.5 - - 3

COD (mg/l) 73.7 94.2 - - 25

DO (mg/l) 0.9 1.4 - - 5-7

TSS (mg/l) 19.0 37.0 - - 50

Faecal coliforms

(counts/100ml)

- - - - 400

Total coliforms

(counts/100ml)

- - - - 5,000

Overview

The water qualities of different zones classified according to the Malayisan In-

terim National Water Quality Standards (INWQS) is summarised in Table 5.15

Table 5.15 Summary of INWQS classification of the different zones of the Sg.

Sarawak system.

Zone DOE INWQS Class

Physical-chemical

parameters

DOE INWQS Class

Bacteriological pa-

rameters

Zone A (Sg. Sarawak Kanan) IIA/IIB

Zone B (Sg. Sarawak Kiri) IIA/IIB

Zone C (Sg. Sarawak main from Batu

Kawa to upstream Satok bridge)

IIA/IIB III

Zone D (Sg. Sarawak main from Satok

Bridge to downstream of barrage)

III V

Zone E (Sg. Maong) IV/V V

Zone F (Sg. Bintangor) IV/V V

Zone G (Sg. Padungan) IV/V V

Zone H (Sg. Sekama) IV/V V

Zone I (Sg. Tabuan) IV/V V

5.2.3 Change in Water Quality

Historical data from DOE indicates that the water quality of Sg. Sarawak de-

clined during the period of 1987-1997 prior to the establishment of the barrage,

mainly due to increased concentration of suspended solids and ammoniacal ni-

trogen (Memon and Murtedza, 1999).



60

5.3 Sediment Quality

The assessment of the sediment quality of Sg. Sarawak focuses on parameters,

which have been chosen as preliminary indicators for sediments in the EMS for

Kuching i.e.:

Nutrients (Ammoniacal Nitrogen, Nitrate, Total Nitrogen, Phosphorus);

Heavy Metals (Hg, Pb, As, Zn, Cd, Cr, Cu, Fe, Ni, CN, Mn);

Polyaromatic hydrocarbons (PAH) and Total Petroleum Hydrocarbon

(TPH); and

Oil & Grease.

Evaluation of the present sediment quality is based on studies performed by the

SUD Project in November 2000 (Sg. Sarawak) and July 2001 (Sg. Kuap) and

by a research group from UNIMAS and the Geological Survey Malaysia (Lau

Seng et al, 1995 and Lau Seng et al, 1998).

5.3.1 SUD Field Study of Sg. Sarawak

The findings of the SUD field study on sediment pollution in Sg. Sarawak con-

ducted in November 2000 are reported in detail in the Volume 3 of the River

Quality Baseline Study Report. The locations of sampling sites are presented in

Figure 5.4

The SUD field study clearly indicates that pollutants from outlets in Kuching

were accumulated in the sediments of Sg. Sarawak. The major findings in terms

of composition of sediments (which is important for the interpretation of the

data on pollutants) and the accumulation of different types of pollutants are

presented below.



61

Fig 5.4. Sampling locations for sediments in Sg. Sarawak in November 2000



62

Composition of sediment

The sediment mainly consists of clay and silt along the stretch of Sg. Sarawak

from S1, upstream of Sg. Maong to S6, downstream of Petanak (Fig. 5.5). Fur-

ther downstream, the sand content increase markedly to S8 at Pending, where

as much as 76% of the sediment consist of sand particles. Downstream of the

barrage at S9, fine grained sediment predominates again. The sandy sediment at

S7 and S8 is probably a result of the flushing procedure at the barrage. During

flushing, the fine-grained particles of the sediment are suspended and trans-

ported downstream of the barrage where they resettled.

Figure 5.5. Composition of sediments at the sampling stations. (The locations

of sampling sites are presented in Fig 5.4)

Organic matter and nutrients

Organic matter from the outlets in Kuching clearly accumulates in the sedi-

ments of Sg. Sarawak. This is indicated by the concentration patterns of loss on

ignition (which is a measure of the content of organic matter), Total N, Total P

and NH4-N observed at the monitoring stations (Fig. 5.6, Fig. 5.7 and Fig. 5.8).

The loss on ignition, which is a measure of the content of organic matter and

the concentrations of Total N and total P, increases from upstream of Kucing

(S1) to Sg. Bintangor (S4). From S4, a gradual decrease is observed and at Kg

Bintawa (S7), the levels have dropped to levels comparable to those encoun-

tered upstream of Kuching (Fig 5.6 and 5.7). The decrease from S4 and further

downstream is probably primarily the result of the flushing procedure at the

barrage.

NH4-N increases dramatically from station S1 upstream of Sg. Maong to S2,

downstream of Sg. Maong from where a gradual decrease is observed to almost

undetectable levels a S7 at Kp Bintawa. (Fig.5.8). NH4-N in the sediment arises

Composition of sediment

0

20

40

60

80

100

120

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

%

Sand, % Silt+clay %



63

from the degradation of nitrogenous organic matter. In aerobic environments,

NH4-N is oxidised to nitrite and further to nitrate. The fact that the highest lev-

els of NH4-N are encountered at S2 and S3 indicates poorer oxygen conditions

in the sediments at these stations compared to further downstream. Improved

oxygen conditions further downstream may be an effect of the flushing at the

barrage, bringing oxygen rich water into the river.

Figure 5.6. Loss on ignition of sediments in Sg. Sarawak in November 2000.

(The locations of sampling sites are presented in Fig 5.4)

Figure 5.7. Concentrations of total N and P in sediments in Sg. Sarawak in No-

vember 2000. (The locations of sampling sites are presented in Fig 5.4).

Loss on ignition

0

2

4

6

8

10

12

14

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

%

Total N and P in sediments

0

500

1000

1500

2000

2500

3000

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

mg

/kg

Tot-N Tot-P m



64

Figure 5.8. Concentrations of total NH4-N in sediments in Sg. Sarawak in No-

vember 2000 (The locations of sampling sites are presented in Fig 5.4).

Heavy metals

The results of the SUD study in November 2000 also clearly show that heavy

metals from outlets in Kuching are accumulated in the river sediments.

The heavy metal concentrations gradually increase from S1 upstream of the

confluence of Sg. Maong to maximum levels at S4, off Sg. Bintangor and S5 at

Holiday Inn. From S5, a gradual decrease of heavy metals is observed to the

downstream location S9, off the Barrage (Figures 5.9-5.12).

This pattern is observed for Pb, Cu, Ni, Cd, Zn, Cr. and Fe. The concentrations

of Mn and Hg do not increase to any appreciable extent downstream of S1, in-

dicating that the City of Kuching is not a major source of Mn and Hg pollution.

The decreasing concentration of heavy metals from Petanak (S6) to Pending

(S8) is probably an effect of the flushing procedure at the barrage. It is evident

from the results of the grain size analysis that the sediment becomes more

sandy around Pending compared to further upstream, indicating that the finer

grained fractions to which heavy metals are mainly adhered/absorbed, are

flushed out to sea.

NH4-N in sediment

0

20

40

60

80

100

120

140

160

180

200

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

mg

/kg



65

Figure 5.9. Concentrations of copper (Cu), lead (Pb), nickel (Ni), chromium

(Cr) and arsenic (As) in sediments in Sg. Sarawak in November 2000 (The lo-

cations of sampling sites are presented in Fig 5.4).

Figure 5.10. Concentrations of Cadmium (Cd) and mercury (Hg) in sediments

in Sg. Sarawak in November 2000 (The locations of sampling sites are pre-

sented in Fig 5.4).

Heavy metals in sediment

0

5

10

15

20

25

S1 S2 S3 S4 S5 S6 S7 S8 S9

station

mg

/kg

Cu Pb Ni Cr As

Cadmium and mercury in sediment

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

mg

/kg

Cd Hg



66

Figure 5.11. Concentrations of zinc (Zn) and manganese (Mn) in sediments in

Sg. Sarawak in November 2000 (The locations of sampling sites are presented

in Fig 5.4).

Figure 5.12. Concentrations of iron (Fe) in sediments in Sg. Sarawak in No-

vember 2000 (The locations of sampling sites are presented in Fig 5.4).

In order to assess the potential adverse biological effects due to heavy metals in

the sediment, the results have been compared to recently developed Canadian

Sediment Quality Standards which relates sediment chemistry data to the poten-

tial for adverse biological effects (CCME, 1999).

Based on a considerable number of studies on the correlation between concen-

tration and toxicity, a Probable Effect Level (PEL) was established for a wide

number of pollutants in sediments. Concentrations equivalent to and above PEL

represents concentrations, which are likely to cause adverse biological impacts.

Zinc and manganese in sediment

0

50

100

150

200

250

300

350

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

mg

/kg

Zn Mn

Iron in sediments

0,00

5.000,00

10.000,00

15.000,00

20.000,00

25.000,00

30.000,00

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

mg

/kg



67

Hg is found above the PEL level on all sampled sites in Sg. Sarawak. Conse-

quently, there may be a risk of adverse biological impacts due to Hg (Cf. Table

5.16). The main source of Hg is however, not the City. Toxic levels are already

encountered upstream of Kuching. The source may be mining activities up-

stream (Cf. section 5.3.2).

The concentrations of the other heavy metals are below PEL and are therefore,

not expected to cause any adverse impacts on organisms.

Table 5.16 Concentration of heavy metals in sediment collected in November

2000 in Sg. Sarawak (mg/kg dry weight). The Canadian Probable Effects

Level (PEL) for the different metals are also shown. Figures in bold exceed

the PEL.

Cu

ppm

Pb

ppm

Zn

ppm

Cd

ppm

Cr

ppm

Hg

ppm

As

Ppm

S1 Upstream Maong 10 10.2 48.6 0.44 3.8 0.73 6.9

S2 Downstream Maong 14.7 17.4 106.0 0.54 4.9 0.92 4.5

S3 Satok bridge 17.6 21.9 131.0 0.63 6.3 0.84 11.6

S4 Bintangor 17.2 22.5 140.0 0.61 6.8 0.81 10.6

S5 Holiday inn 17.5 23.3 134.0 0.63 7.1 0.93 6.5

S6 Petanak 15.0 20.9 100.0 0.52 9.4 0.62 10.7

S7 Kp Bintawa 12.3 14.9 82.9 0.41 4.2 0.77 4.9

S8 Pending 4.1 6.9 26.9 0.34 3.7 0.64 9.2

S9 Downstream barrage 4.8 9.0 32.4 0.37 4.8 0.63 6.3

PEL 197.0 91.3 315.0 3.5 90.0 0.49 17.0

Pesticides

Pesticides were not found in any of the sediment samples. All pesticides ana-

lysed were below the detection limits (0.001 mg/kg for organochlorinated pes-

ticides (0.005 mg/kg for chlordane) and 0.01 mg/kg for organophosphorated

pesticides.

Petroleum hydrocarbons

Polyaromatic Hydrocarbons PAHs were also not found. All individual PAHs

analysed for were below the detection limit of 0.1 mg/kg.

Elevated concentrations of Total Petroleum Hydrocarbons (TPH) compared to

upstream of Kuching were encountered at Satok Bridge (S3) and Sg. Bintawa

(S7) (Fig. 5.13).



68

Figure 5.13. Concentrations of Total Petroleum Hydrocarbons (TPH) in sedi-

ments in Sg. Sarawak, November 2000. The locations of sampling sites are pre-

sented in Fig 5.4)

5.3.2 SUD Field Study Sg. Kuap

The findings of the SUD field study on sediment pollution in Sg. Kuap con-

ducted in July 2001 are reported in detail in the Volume 3 of the River Quality

Baseline Study Report. The sampling locations are indicated in Fig. 5.14.

The study clearly indicates that heavy metals from the Sama Jaya Free Indus-

trial Zone are accumulated in the sediments of Sg. Kuap.

The concentrations of heavy metals increase markedly from upstream of the

industrial estate to the area off the estate. Further downstream, a slight decrease

is observed for most metals (Figs 5.15-5.17). This pattern indicates that the in-

dustrial estate is a source contributing heavy metals to the sediments.

Although heavy metals are accumulated in the sediments, the concentrations

are below levels, which are likely to be toxic to aquatic organisms. The concen-

trations are below the Canadian Probable Effect Levels (Cf. Table 5.17).

Similar to Sg. Sarawak, pesticides were not found in any of the sediment sam-

ples from Sg. Kuap. All pesticides analysed were below the detection limits.

TPH in sediments

0

50

100

150

200

250

300

350

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

mg

/kg

(C

15-C

36)



69

Fig 5.14. Sampling locations for sediments in Sg. Kuap and Sg. Sarawak in

July 2001. The Red box indicate the Samajaya Free Industrial Zone.

SD1

SD2

SD3

SD4

N



70

Figure 5.15. Concentrations of copper (Cu), lead (Pb) nickel (Ni), chromium

(Cr) and arsenic (As) in sediments in Sg. Kuap July 2000.

Figure 5.16. Concentrations of cadmium (Cd) in sediments in Sg. Kuap July

2000.

0

5

10

15

20

25

30

SD4 SD3 SD2

mg

/kg

Cu Pb Ni Cr As

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

SD4 SD3 SD2

mg

/kg



71

Figure 5.17. Concentrations of zinc (Zn) in sediments in Sg. Kuap July 2000.

Table 5.17 Concentration of heavy metals in sediment collected in July 2000

in Sg. Kuap (mg/kg dry weight). The Canadian Probable Effects Level (PEL)

for the different metals are also shown.

Cu

ppm

Pb

ppm

Zn

ppm

Cd

ppm

Cr

ppm

As

ppm

SD4 Upstream 0.8 3.0 6.6 0.24 2.00 5.3

SD3 28.0 27.8 121.0 0.78 7.4 0.03

SD2 10.3 23.5 72.9 0.83 20.9 2.1

PEL 197.0 91.3 315.0 3.5 90.0 17.0

5.3.3 Previous Research Studies

All results from the previous research studies carried out by the research group

from UNIMAS and the Geological Survey Malaysia is summarised in Table

5.18. Sampling sites are indicated on Figure 5.18 and 5.19.

Zn

0

20

40

60

80

100

120

140

SD4 SD3 SD2

mg

/kg



72

Figure 5.18. Sediment sampling sites. S1= upstream of confluence of Sg. Sara-

wak and Sg. Maong. S2= Downstream of the confluence of Sg. Sarawak and

Sg. Maong. S3= At the Satok Bridge. S4= Off Sg. Bintangor. S5= Off Holiday

Inn. S6= Off Kuching Port Authority. S7=Off tributary west of Kp Bintawa.

S8= Off Pending. S9=Downstream of the Barrage.



73

Figure 5.19. Sediment sampling sites.



74

Sg. Sarawak Kiri

The concentrations of heavy metals in the sediments of Sg. Sarawak Kiri was

generally very low, in many cases below the detection limit and all cases below

levels which may be toxic to sensitive organisms. However, high concentra-

tions of iron were encountered.

As described in section 5.2.1, this is not related to human activities, as high

background concentrations of iron are to be expected in the river system.

Sg. Sarawak Kanan

The contents of heavy metals in the sediments of Sg. Sarawak Kanan were sig-

nificantly higher than in Sg. Sarawak Kiri. Very high and toxic concentrations

of As and Hg were encountered. The concentrations of Cd, Cr and Pb were also

quite high. The study indicates that the source of these metals is located be-

tween Bau and Buso where previous gold mining activities and quarry opera-

tions has taken place (Fig 5.20). The polluted sediments will gradually be

transported downstream and may affect the sediments in the part of the river

running through Kuching.



75

Table 5.18 Heavy metals in sediments in the Sg. Sarawak system found by

UNIMAS and the Geological Survey Malaysia. (- = not measured; nd = not

detected). The Canadian Probable Effects Level (PEL) for the different met-

als are also shown. Figures in bold exceed the PEL.

As

ppm

Cd

ppm

Cr

ppm

Cu

ppm

Hg

Ppm

Ni

ppm

Pb

ppm

Se

ppm

Zn

ppm

Fe

ppm

Ref

Sg. Sarawak Kiri

Padawan <2 <0.4 2.4 <1 <0.04 1.6 7.8 7.2 6.4 3160 1

Sg. Nibong <2 <0.4 3.2 <1 <0.04 3.9 7.8 3.4 18.4 7120 1

Annah Rais <2 <0.4 1.8 <1 <0.04 <1 6.8 4.2 4.4 2380 1

Batu Kitang <2 2.8 10.8 4.2 <0.04 5.2 27.4 <2 41.2 12160 1

Sg. Sarawak

Kanan

Pejiru/Sg. Noren <2 <0.4 1.2 <1 <0.04 1.2 2.8 10.3 8 3460 1

Bau 9.8 <0.4 3.8 <1 <0.04 2.2 10 <2 14.4 5680 1

Bau water intake 1.2 nd - 1.1 nd - 0.52 - 3.3 - 2

Sg. Bau 83.7 0.67 - 4.4 0.1 - 3.5 - 21.2 - 2

Bau confluence 6.3 nd - 3.4 0.02 - 0.7 - 6.95 - 2

Buso 147 3.2 15 3.6 160 5.6 46.8 30.6 44.1 19400 1

Buso 6.3 nd - 1.4 0.01 - 1.1 - 3.5 - 2

Siniawan 4.3 0.25 - 1.95 0.01 - 0.8 - 6.5 - 2

Kp Keranji 51.4 2.8 16 3.8 52 5.8 40 20.2 26.2 18220 1

Kp Keranji 5.3 0.08 - 1.2 0.03 - 0.8 - 3.3 - 2

Sg. Sarawak

Main

Rantau Panjang 22.6 3.8 11.8 4 56 6 33.8 19.2 39.8 16880 1

Batu Kawa 19.8 3.2 16 5.2 <0.04 6.4 39.2 <2 39 18320 1

Batu Kawa 1.8 0.25 - 1.7 0.02 0.6 4.7 - 2

North J. Point 9.2 3 9.2 10 <0.04 7.2 46.6 22.4 48.4 17780 1

Muara Tebas 12.4 4.4 6 10 <0.04 8 187 13.4 37 19560 1

Sg. Maong -

Sg. Maong main - 4.3 19.7 21.2 - - 31.5 - 179.2 - 3

Sg. Maong main - 3.3 20.1 24.2 - - 41.6 - 207.5 - 3

Sg. Maong Kanan - 4.5 22.6 29.5 - - 50.2 - 352.7 - 3

Sg. Maong Kanan - 5.8 24.2 30.2 - - 122.5 - 1315.1 - 3

Sg. Maong Kiri - 3.2 20.8 28.9 - - 38.5 - 190.4 - 3

Sg. Maong Kiri - 4.7 18.9 39.6 - - 52.9 - 321.2 - 3

Sg. Maong Kiri - 3.5 16.2 24.0 - - 24.1 - 105.8 - 3

Sg. Maong Kiri - 2.9 4.0 8.2 - - 20.6 - 82.4 - 3

Sg. Maong Kiri - 5.3 19.3 31 - - 41.1 - 200.3 - 3

Sg. Maong Kiri - 4.9 21.4 63 - - 60.5 - 395.9 - 3

PEL 17.0 3.5 90.0 197.0 0.49 - 91.3 - 315 -

1) S Lau, M. Mohamed and Subtuyah Suùt (1995) Profile of heavy metals in water and bottom

sediments of Sg. Sarawak. Malaysian Chemical congress 95.

2) S. Lau, M. Mohamerd, A. Tan Chi Yen and S. Suùt (1998). Accumulation of heavy metals in

freshwater molluscs. The Science of the Total Environment 214 (1998) 113-121

3) S. Lau Pereira T.J Wong L.K. and Chai (1998) The study of sediment and Water qualities of Sg.

Maong, Sarawak. Malaysian Chemical congress



76

Figure 5.20. Concentration of As and Hg in sediments of Sg. Sarawak Kanan

(Bau, Buso and Kp Keranji) and Sg. Sarawak Main (Batu Kawa and Muara

Tebas) found by Lau Seng et al 1995.

Sg. Sarawak Proper

The studies show that concentrations of heavy metals increase between Batu

Kawa and Muara Tebas, which are in accordance with the SUD study.

Sg. Maong

The concentration of heavy metals in Sg. Maong was significantly higher than

those found in Sg. Sarawak (compare Table 5.16 and 5.18). Potentially toxic

levels of Cd, Pb and Zn were encountered in Sg. Maong.

5.4 Accumulation of Pollutants in Organisms

Following the discovery that sediments were polluted by heavy metals from

gold mining and quarry operations in the Bau areas, the research group from

UNIMAS and Geological Survey Malaysia carried out a study on accumulation

of heavy metals in freshwater molluscs (Lau Seng et al. 1998). Sediment sam-

ples and freshwater molluscs (Clithon sp., Brotia costula and Melanoides tu-

berculata) were collected at the same sites and analysed for heavy metals

The molluscs obviously accumulated As, Cu and Zn from the sediments and the

results clearly indicated that the heavy metal source was Sg. Bau. Figure 5.21

shows an example (Concentration of Arsenic in sediments and the molluscs

Clithon sp. and Brotia costula).

All the molluscs collected from the study area were found contaminated with

As and the levels of Cu and Zn were at the maximum concentration allowable

for seafood as stipulated by the Food Act (1983). Levels of Cd, Hg and Pb were

however low in the molluscs tissues collected for the study.

0

20

40

60

80

100

120

140

160

180

Bau Buso Kp Keranji Batu Kawa Muara Tebas

mg

/kg

As Hg



77

There are no data from the river system in the Kuching area.

Figure 5.21. Concentration of Arsenic in sediment and two freshwater mol-

luscs (Brotia costula and Melanoides tuberculata) upstream and downstream of

heavy metal sources at Sg. Bau.

5.5 Ecosystem Impacts

In order to be able to assess the impacts of the pollution of the river on aquatic

organisms, a pilot study on benthic macroinvertebrates was carried out by the

SUD Project in November 2000 in connection with the sediment study.

Benthic macroinvertebrates (benthos) in the lower reaches of rivers and in the

sea are from a wide variety of species of mainly oligochaete and polychaete

worms, mussels, snails, starfish, sea urchins and crustaceans living in burrows

in the sediment or on the sediment surface.

Benthos samples were collected at the same time and at the same sites as the

sediment samples (Cf. Fig 5.4) in order to be able to relate sediment contamina-

tion impacts on benthic fauna.

The findings of the SUD field study on sediment pollution in Sg. Sarawak con-

ducted in November 2000 are reported in detail in the Volume 3 of the River

Quality Baseline Study Report. The major findings are presented below.

Composition of fauna

Oligochaete worms dominates the fauna in Sg. Sarawak upstream of the bar-

rage. Tubificidae worms are the most common, with Tubifex occurring as the

most common genus. Downstream of the barrage oligochates were absent and

marine molluscs dominate the fauna.

0

10

20

30

40

50

60

ST 1 upstream ST 3 downstream

mg

As/

kg d

ry w

t.

Sediment Brotia Cliton



78

Diversity index

The diversity and species richness of macrobenthos generally show an increase

downstream from S1 to S10 (Fig 5.22).

Figure 5.22. Diversity index (H`=Shannon Wiener index) and species richness

(R1= Margaleffs index) at each sampling site. For calculations of these refer-

ence is made to Volume 3 of the river quality baseline study. The locations of

sampling sites are presented in Fig 5.4.No organisms were encountered at S5

due to hard substrate on which the sampler did not function.

Environmental factors affecting the fauna

There are strong indications that the organic matter discharged from Kuching

affects the benthos, upstream of the barrage.

Based on a substantial amount of data, Pearson & Rosenberg (1978) found a

general succession pattern of benthic infauna in response to increased input of

organic material to the sediment:

Initially increasing input of organic matter will result in an increase in the

number of species, the biomass and the density (abundance) of organisms

because the amount of food for organisms increases (many benthic species

feed on organic matter on the seabed);

When the input reaches a certain level, the number of species and, the bio-

mass and the density decline. The reason behind this is that the oxidised

layer of the sediment becomes thinner because the organic matter consumes

oxygen;

0

0,5

1

1,5

2

2,5

3

3,5

4

S1 S2 S3 S4 S5 S6 S7 S8 S9

Station

Div

ersi

ty I

nd

ex (

H')

Sp

ecie

s R

ichnes

s (R

1)

Shannon Weaver Diversity Index Margalef Richness Index



79

At very heavy loads, oxygen depletion in the sediment may periodically

take place. Only very few species can tolerate in such conditions. As a re-

sult, the numbers of species decrease further. Longer periods of oxygen de-

pletion lead to the extinction of the fauna. In case of oxygen conditions

have improved, the area will be re-colonised rapidly by a very few known

as opportunistic species, which may be found in high densities.

The benthos data from Sg. Sarawak can be interpreted in the context of the

Pearson & Rosenberg succession of benthos in relation to increasing organic

load.

Abundance (number of individuals) and number of species of benthos are com-

pared to the content of organic matter in the sediment (measured as loss on ig-

nition) in Figure 5.23.

It is evident that the abundance of species and the number of species increase

concurrently with an increase in the content of organic matter when moving

from Pending (S8) and upstream to Petanak (S6) and off Sg. Bintangor (S4).

This is probably as a result of increasing amount of food in the form of organic

matter.

At the Satok Bridge (S3) and downstream of Maong (S2), the abundance and

number of species drop dramatically despite the fact that the organic contents

are similar to S6 and S4. The drop is probably an effect of poor oxygen condi-

tions in the sediment. High levels of NH4-N are thus encountered here indicat-

ing poor oxygen conditions (Fig 5.24). The relatively better oxygen conditions

further downstream at S4 and S6 may be an effect of the flushing at the barrage,

bringing oxygen rich water into the river.

This interpretation is strongly supported by the fact that the fauna is completely

dominated by species of Oligochaete worms and that the changes in abundance

and number of species described above is largely changes in abundance and

number of species of Oligochaetes. Oligochaetes have been recognised as bio-

indicators for organic pollution (Canfield et al 1994, 1996). They are deposit

feeders, subsisting on organic detritus and its associated microflora feeding on

detritus in the sediment. Generally, they can tolerate quite low oxygen concen-

trations and may be found in large numbers in organical polluted habitats.



80

Figure 5.23. Abundance (number of individuals) and number of species of ben-

thos compared to the content of organic matter in the sediment (measured as

loss on ignition). The locations of sampling sites are presented in Fig 5.4.

0

200

400

600

800

1000

1200

1400

1600

1800

S8 S7 S6 S4 S3 S2 S1

Station

ind

ivid

uals

/m3

0

2

4

6

8

10

12

14

% L

oss o

n ig

nit

ion

Abundance LOI, %

0

1

2

3

4

5

6

7

S8 S7 S6 S4 S3 S2 S1

Station

nu

mb

er

0

2

4

6

8

10

12

14

% L

oss o

n ig

nit

ion

No species LOI, %



81

Figure 5.24. Abundance (number of individuals) and number of species of ben-

thos compared to the content of NH4-N in the sediment. The locations of sam-

pling sites are presented in Fig 5.4.

The higher diversity and species richness at S9 downstream of the barrage is

probably due to the fact that the salinity in this area is higher. The fauna is be-

ing dominated by the presence of marine molluscs and bivalves. Higher species

diversity is generally encountered in more saline waters compared to more

brackish waters.

5.6 Floating Debris

The presence of floating debris is aesthetically unpleasant and presents a hazard

to river travel. In a study carried out by DHV Consultants in Nov/Dec 1990 and

Jan/Feb, a generation of floating waste was estimated at 18,800 – 22,000

0

200

400

600

800

1000

1200

1400

1600

1800

S8 S7 S6 S4 S3 S2 S1

Station

ind

ivid

uals

/m3

0

20

40

60

80

100

120

140

160

180

200

mg

/kg

NH

4-N

Abundance NH4-N

0

1

2

3

4

5

6

7

S8 S7 S6 S4 S3 S2 S1

Station

Nu

mb

er

of

sp

ecie

s

0

20

40

60

80

100

120

140

160

180

200

mg

/kg

NH

4.-

N

No species NH4-N



82

m3/year. DBKU has the yearly measurements of the volume of floatables. The

amount of floatables has decreased from some 125,000 m3/year in 1994 to

45,000 m3/year in 1999 (Figure 5.25). The DHV study estimated the composi-

tion of floating debris as follows:

About 80% of the debris were river and river bank vegetation (bamboo, ni-

pah palm cut-offs, water hyacinth, branches and logs);

About 15 % were wood waste (tree branches, logs, sawdust, sawn timber

planks and off cuts); and

About 5 % were municipal solid waste (plastic bottles and containers, plas-

tic bags, steel and aluminium cans, paper/cardboard packaging, polystyrene

foam, aerosol cans, etc.).

Another study carried out by KTA (Sarawak) Sdn Bhd in 1997 confirmed that

majority of the floatables found in Sg. Sarawak were still bamboo and vegeta-

tion. However, inspection by boat used during the study revealed that the pro-

portion of wood waste appeared to be greater than the previously determined of

15%.

Figure 5.25. Amount of floatables (m3) collected by DBKU on Sg. Sarawak.

1994-1999.

0

20000

40000

60000

80000

100000

120000

140000

year 1994 year 1995 year 1996 year 1997 year 1998 year 1999

m3

flo

ata

ble

s



83

6 Sources of Pollution and Pollution load

6.1 Overview of Pollution Sources

Sg. Sarawak and its main tributaries are receiving large amounts of sewage and

wastewater from a wide variety of sources both from Kuching and upstream of

Kuching.

At the SUD workshop on Preliminary Goal setting in November 1999, the pos-

sible sources of pollutants to the river were identified (reported in SUD report

“Preliminary goals, targets and indicators for sustainable urban development in

Couching Sawara (SUD-02-03, SUD-02-07). The major sources were identified

as:

Households;

Food outlets including markets, restaurants and coffee shops;

Small and Medium Industries (SMI) and Large Scale Industries (LSI);

Agriculture; and

River vessels.

The pollutants generated from these activities were identified during the work-

shop (Table 6.1). The amounts of wastewater and contaminants were not quan-

tified during the workshop. Previously, there has been no attempt to estimate

the pollution load from different sources in Kuching. During the baseline study,

the first attempt to quantify load from different sources were made. Details on

the estimation of pollution load from different sources are presented in Volume

2 of the River Quality Baseline Study Report and the major findings are pre-

sented in the following sections.



84

Table 6.1 Factors affecting the Sarawak River quality.

Source Pollutants

Upstream based

sources

Agriculture, including live-

stock

Faecal and total coliforms

Nutrients (especially N and P)

BOD

COD

Pesticides

Mining Cyanide

Mined minerals and metals (Hg, As etc.)

Kuching based

sources:

Food outlets and house-

holds

Faecal and total coliforms

Nutrients(especially N and P)

BOD

COD

Suspended solids

Grease and oil

Industries

(A detailed outline of pol-

lutants from different types

of SMIs and LSIs is pre-

sented in Table 6.8)

Heavy metals

Oil and grease

Other inorganic substances and compounds

Organic compounds, such as organic solvents,

residue from industrial processes and products

Micro organisms

COD, BOD, AOX

Vessels Heavy metals

Organic solvents

Oil spills

Types of pollutants, discharge, treatments facilities, number of sources as well

as estimated loads from households, food outlets and industries are described in

sections 6.2, 6.3 and 6.4 below. Pollution from agriculture and other sources are

described in sections 6.5 and 6.6.

6.2 Pollution from Households

6.2.1 Types of Pollutants from Households

Domestic sewage can be separated into blackwater, which is body wastes (fae-

ces and urine) and greywater, and all other liquid wastes of the household, in-

cluding laundry, bathroom/washroom and kitchen wastewater. Body wastes are

the most hazardous due to the possibility of contact with intestinal disease or-

ganisms. Greywater has fewer disease organisms unless the laundry has con-

tained garments soiled by faecal discharges.

The most significant pollutants in grey- and blackwater which have been cho-

sen as indicators for pollution from households are ammoniacal nitrogen, phos-

phorous, BOD, COD, faecal coliforms, total coliforms and TSS.



85

6.2.2 Estimated Population and Number of Households

The SUD Project has estimated the population size and the number of different

types of houses in the twelve catchment areas, which are discharging to Sg. Sa-

rawak upstream of the barrage (Cf. Fig. 4.3 in section 4.1). Details are pre-

sented in Volume 2 of the River Quality Baseline Study Report. In year 2000, a

total population of 215,000 people living in about 26,000 houses was identified

in these catchment areas. The most important residential areas being (Table

6.2):

1. The Maong sub-catchment area with 94,192 inhabitants;

2. Padungan (15,619 inhabitants);

3. Bintawa 1 (11,901 inhabitants);

4. Seman Lama (11,485 inhabitants); and

5. Sinjan (10,641 inhabitants).

Not included in these estimates is a residential area in the catchment of Sg.

Kuap (mainly around Sg. Tabuan). The population in this area has been esti-

mated at about 100,000 (SPU, 1998).



86

Table 6.2 Population and numbers of different types of Households in differ-

ent Sub-catchment areas. Locations of the sub-catchment areas are shown on

Fig 4.3 Section 4.1.

Catchment Popu-

lation

De-

tached

houses

Semi-

detached

houses

Terrace

houses

Flats Kam-

pung

houses

Total

house-

holds

South of Sg.

Sarawak

Bintangor 1 4,402 136 28 - - 131 295

Bintangor 2 6,645 176 140 176 250 336 1078

Bintangor 3 5,749 14 - 14 102 52 182

Padungan 15,619 512 250 1,596 670 - 3028

Sekama 3,513 65 86 194 - - 345

Sekama 1 2,253 64 32 82 - - 178

Periok 741 55 20 10 - - 85

Biawak 2,810 - - 100 144 - 244

Bintawa 1,601 - - - - - -

Bintawa 1 11,901 32 152 605 - - 789

Kudei 8,151 64 223 1,102 - 96 1485

Maong 94,192 3,150 3,208 4,944 1,186 - 12,488

North of Sg.

Sarawak

Gita 8,937 69 188 346 - - 603

Laruh 5,975 139 290 409 - - 838

Turong 1,356 30 12 28 - 141 211

Sinjan 10,641 196 78 578 - 390 1242

Bedil 9,167 - - - - 801 801

Gersik 2,504 - - - - 258 258

Seman Lama 11,487 - - - - 1719 1719

Siol Kandis 1 7,489 2 450 - - 23 475

Siol Kandis 2 558 85 - - - - 85

Total 215,664 4,789 5,157 10,184 2,352 3947 26,429

6.2.3 Treatment Facilities and Draining Systems

Greywater

Almost all houses in Kuching discharge untreated greywater directly into the

stormwater drains in the city. The stormwater drain is an extensive open chan-

nels system which discharges into smaller tributaries (Sg. Maong, Sg. Bintan-

gor, Sg. Padungan, Sg. Sekama etc) or directly to Sg. Sarawak.

The only measure to reduce contaminants from entering the drains is the usage

of coarse filtering equipment installed at washing sinks.



87

Blackwater

Houses are generally equipped with individual septic tanks for the treatment of

blackwater. Then, the effluent from the septic tanks discharge to the drains and

then to the river.

Septic tank serve as a combined settling and skimming tank and an anaerobic

digester, which decompose organic matter.

Heavier solids from the incoming wastewater settle and form a sludge layer at

the bottom of the tank. Grease and other light materials float on the surface

where a scum layer is formed as floating materials accumulated.

The organic material retained in the bottom of the tank undergoes anaerobic

decomposition and is degraded to more stable compounds and gases such as

carbon dioxide (CO2), methane (CH4) and hydrogen sulphide (H2S).

Even though the volume of the solid material being deposited is reduced con-

tinuously by anaerobic decomposition, there is always a net accumulation of

sludge in the tank. Materials from the bottom of the tank, which is buoyed up

by the decomposition gases, will often stick to the bottom of the scum layer and

increase its thickness. The long-term accumulation of scum and sludge can re-

duce the effective volumetric capacity of the tanks. Therefore, in order to func-

tion the tanks must be desludged regularly (according to Danish experience at

least once a year).

There are basically three types of septic tank i.e. tanks with one-, two- or three

chambers. The function of the compartments is basically to limit the discharge

of solids in the effluent from the septic tank. According to the Sg. Bintangor

study, the most common type used in the Sg. Bintangor catchment area is a

conventional two-compartment tank of a standard size of 2.3-2.6 m3.

Septic tanks are not very efficient. According to Danish experience (Danish

EPA pers comm., 2000), only about 30 % of the organic matter are removed

prior to discharge, even in the most efficient three-chambered type with a ca-

pacity of at least 2 m3. Tanks with less number of chambers and in smaller ca-

pacity are apparently less efficient. In addition, nutrients are basically not all

removed in septic tanks. As much as 72% and 76 % of the total discharge of

Phosphorous and Nitrogen, from households are from blackwater (SUD-02-13).

Consequently, even an optimal functional septic tank in Kuching is a one of th

esignificant sources of organic matter and nutrients.

The Rule of “Compulsory desludging of septic tanks, 1988” gazetted 15th Octo-

ber 1998 specifies that every septic tank in the city must be desludged every

second year. The Sg. Bintangor study showed that this rule is not complied

with. It was estimated that only 840 septic tanks of around 3,000 in the Sg. Bin-

tangor catchment area was desludged in a two year period i.e. only about 30%

of those which should have been desludged according to the rule. Presently,

tanks are only pumped out at the request of the owner when there is a problem

or blockage of the system.



88

On 1st January 2000, DBKU launched a programme in which the two-year

desludging period for septic tanks must be applied. The two subcontractors

ENV and TRAMAS carry out the desludging for DBKU and the sludge is

treated at the Matang Septic Sludge Treatment Plant. It may, however, be very

difficult to achieve the intention of programme. According to the Sg. Bintangor

study (SUD-02-09), more than 95 % of the septic tanks were in fact not acces-

sible and many people did not even know whether they had septic tanks or not.

As a consequence of the improper function of septic tanks, blackwater is dis-

charged more or less untreated to the drainage system in Kuching. Untreated

blackwater from households is undoubtedly the main source of the extremely

high levels of faecal coliforms in the tributaries and Sg. Sarawak Proper as well

as a major source contributing the organic matter and nutrients.

It must be stressed that even if all septic tanks in Kuching were desludged regu-

larly and functioning properly, the effect of reducing the load to the tribuatries

and Sg. Sarawak Proper will be insignificant. Rough estimates of the discharge

of BOD, Nitrogen and Phosphorous to Sg. Sarwak in the case of all septic tanks

are not functioning and in case of all septic tanks are functioning optimally are

presented in Fig. 61. The discharge of BOD will still be very high and the dis-

charge of nitrogen and phosphorous are not reduced at all.

Figure 6.1. Estimated discharge to Sg. Sarawak of BOD, Nitrogen and Phos-

phorous in blackwater in case none of the septic tanks are functioning and in

case all are functioning optimally. The estimates are based on the population

size of 215,000 in the sub-catchment areas discharging to Sg. Sarawak and a

generation of 20g BOD/person/day, 11g Nitrogen/person/day and 1,6 g Phos-

phorous/person/day and an efficiency of 30% removal of BOD in a functioning

septic tank)

There are some central treatment-facilities (mostly septic tanks and Imhoff

tanks) servicing larger housing schemes. The locations of these are presented in

Fig. 6.2.

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

BOD Nitrogen Phosphorous

kg/d

ay

None functioning All functioning



89

6.2.4 Control and Enforcement Measures

Presently, there are no active control and enforcement measures implemented

for household discharge in Kuching. As mentioned above, septic tanks are

pumped out at the request of the owners. However, there is no control on

whether the tanks comply with the stipulated water quality standards or whether

the two-year desludging period is complied with especially when the public

awareness regarding septic tanks is quite low.

6.2.5 Estimated Ttotal Load of Pollutants from Households

The total load of different pollutants from households in the twelve sub-

catchment areas have been estimated based on the results of measurements on

greywater from the households and the numbers of different households. Alter-

native estimates based on population size and estimated loads per person from

the measurements in Kuching and European values were also elaborated. Esti-

mated load from blackwater was based on European values. It was assumed

that the blackwater is discharged untreatedly. Details are presented in Volume 2

of the River Quality Baseline Study Report. The main findings are presented

below.

None of the households visited in the SUD study complied with the standards

as stipulated in the Environmental Quality (Sewage and Industrial Effluents)

Regulations, 1979. The levels in the outlets generally exceeded the standard A

2-17 times for BOD, 1.1-11 times for COD and 1.5 times for TSS (Cf. Table

6.3). Non-compliance with the standards is most likely the case for the bulk of

the houses in Kuching as the sewage is not treated before discharge.



90

Table 6.3 Households. Results analysis of pollutants in greywater. The values

are compared to the standards as stipulated in the Environmental Quality

(sewage and industrial effluents) regulations, 1979. Figures in italic bold in-

dicate values exceeding the Standard A and figure in bold also exceed the

Standard B values.

De-

tached

Semi-

de-

tached

Terrace Kam-

pung

Squat-

ter

Stan-

dard A

Stan-

dard B

PH 6.6 9.6 6.7 7.9 6.4 6-9 5.5-9

BOD, mg/l 43.0 159.0 333.0 114.0 47.0 20 50

COD, mg/l 76.2 400.0 533.0 133.0 57.1 50 100

TSS, mg/l 30.0 74.0 225.0 101.0 174.0 50 100

NH4-N mg/l 0.2 2.7 43.4 80.3 0.3

Tot-N, mg/l 4.8 17.4 58.5 93.9 2.2

Tot-P, mg/l 5.6 19.2 56.7 6.4 5.9

Oil & Grease, mg/l 2.8 <0.5 55.3 31.4 11.0 n.d 10

n.d. = not detectable

The estimates of the discharge of pollutants are presented in Table 6.4. In ac-

cordance with the distribution of houses, the highest pollution load was dis-

charged from the Maong sub-catchment area followed by Padungan, Bintawa 1,

Seman Lama and Sinjan (Table 6.1).

The load of BOD from the residential area in the Sg. Kuap catchment can be

roughly estimated at 3,000-4,500 kg/day, i.e. in the same order of magnitude as

the discharge from households in the Sg. Maong catchment area. The estimate

is based on European value of 20g BOD/person/day in blackwater and 25g

BOD/person/day in greywater as well as the value of 11.5g/person/day meas-

ured in greywater during the SUD field study in Kuching.



91

Table 6.4 Households. Estimated loads of different pollutants from different

catchment areas (kg/day) from both grey and blackwater.

Catchment BOD

Kg/day

COD

Kg/day

TSS

Kg/day

Tot N

Kg/day

Tot P

Kg/day

South of Sg.

Sarawak

Bintangor-1 106-198 349-528 100-167 53-70 9-12

Bintangor-2 199-299 595-797 178-253 80-105 17-18

Bintangor-3 126-259 434-690 123-218 68-91 10-16

Padungan 494-703 1452-1874 439-594 189-249 42

Sekama 91-158 290-422 85-133 43-56 8-9

Sekama 1 56-101 181-270 53-86 27-36 5-6

Periok 20-33 63-89 18-28 9-12 2

Biawak 71-126 229-337 66-107 34-44 6-8

Bintawa 32-72 115-192 32-61 18-25 3-4

Bintawa 1 286-536 942-1428 271-452 144-188 23-32

Kudei 254-367 747-978 225-310 99-129 21-22

Maong 2646-4239 8131-11303 2407-3579 1140-1488 219-254

North of Sg.

Sarawak

Gita 216-402 709-.072 204-340 108-141 18-23

Laruh 171-269 521-717 155-227 72-94 14-16

Turong 40-61 120-163 36-52 16-21 3-4

Sinjan 288-478 898-1.274 264-403 128-168 24-29

Bedil 232-413 747-1.100 217-348 111-145 19-25

Gersik 66-113 208-300 61-95 30-40 5-7

Seman Lama 335-517 1.013-1.378 302-437 139-181 28-31

Siol Kandis 1 179-337 591-899 170-285 91-118 15-20

Siol Kandis 2 16-25 49-67 15-21 7-9 1-2

Total 5925-9705 19927-25880 5421-8195 2610-3407 490-582

6.3 Pollution from Food Outlets

6.3.1 Types of Food Outlets and Types of Pollutants

Food outlets comprise:

Food centres with several different stalls serving food;

Individual restaurants, coffee shops and fast food restaurants; and

Markets.

The most significant pollutants in wastewater, which have been chosen as indi-

cators from food outlets are ammoniacal nitrogen, phosphorous, BOD, COD,

TSS and Oil & Grease.



92

6.3.2 Estimated Number of Different Food outlets

The SUD Project has estimated the number of different types of food outlets in

the twelve catchment areas, which are discharging to Sg. Sarawak upstream of

the barrage. The result is summarised in Table 6.5. The food centres and indi-

vidual restaurants are mainly located at the south of Sg. Sarawak, mainly at the

Sg. Maong and Sg. Padungan sub-catchment areas (Table 6.5). Large markets

with more than 100 stalls are located in Bintangor 2, Bintangor 3, Padugan and

Maong.

Table 6.5 Number of different types of Food-outlets in different Sub-

catchment areas. Locations of the sub-catchment areas are indicated on Fig

4.3 in section 4.1

Catchment Food Center Individual

Restaurants,

Coffee Shops

and Fast Food

Restaurants

Big Markets

(more than

100 stalls)

Medium

Markets (Be-

tween 50 and

100 stalls)

Small Mar-

kets

(Less than 50

stalls)

South of Sg.

Sarawak

Bintangor 1 - - - - -

Bintangor 2 1 48 2 1 -

Bintangor 3 2 88 1 2 -

Padugan 2 108 2 - -

Sekama - 73 - - -

Sekama 1 - 6 - - -

Periok - 16 - - -

Biawak 1 22 - 1 -

Bintawa - 8 - - -

Bintawa 1 - - - - 1

Kudei 1 8 - - 1

Maong 1 131 1 - -

North of Sg.

Sarawak

Gita 1 - - - -

Laruh 1 - - - -

Turong - - - - -

Sinjan - 4 - - 1

Bedil - - - - -

Gersik - - - - -

Seman Lama - - - - -

Siol Kandis 1 - - - - -

Siol Kandis 2 - - - - -

Total 10 512 6 4 3



93


The food outlets discharge wastewater to the open drains in the city. Most food

outlets discharge untreated water while have equipped with some form of

treatment facilities. The treated water from such facilities is also discharged to

the drain. Treatment facilities include:

Crude devices in the form of steel basins, which serves to trap oil and

grease and collect solid food residues washed down from the kitchen sinks

in restaurants;

Filtration systems consisting of “sponge-like” filter material installed at the

bottom of the washing sink of restaurants to trap large solid food residues

washed into the sink‟s piping system; and

Grease traps installed at the outlet to the peripheral drains.

The Sg. Bintangor study (SUD-02-09) indicated that the grease traps are gener-

ally not functioning because they were not emptied and in the case they are ac-

tually emptied, it seemed that this generally took place in the drain downstream

of the trap.

At present, information on numbers of food outlets with treatment facilities is

not available.


Presently, the Local Councils spend huge resources in cleaning the oil and

grease in the drains downstream of food outlets.

6.3.5 Estimated Total Load of Pollutants from Food Outlets

The total load of different pollutants from different types of food outlets in the

twelve sub-catchment areas have been estimated based on the results of meas-

urements on wastewater from different types of outlets and the estimated num-

ber of different types of food outlet. Details are presented in Volume 2 of the

River Quality Baseline Study Report. The main findings are presented below.

The greywater from the food outlets investigated in this study does not comply

with the standards as stipulated in the Environmental Quality (Sewage and In-

dustrial Effluents) Regulation, 1979 (Table 6.6). The levels in the outlets gener-

ally exceed the Standard A:

13-42 times for BOD;

2-21 times for COD; and

2-7 times for TSS.



94

Compliance for the food centre, coffee shop and market could not be expected,

as the water is not treated in any way before discharge. The restaurant has a col-

lection basin after outlet from kitchen sink and the fast food restaurant has a

filtration system after the outlet from kitchen sink. These systems are not suffi-

cient for a proper wastewater treatment.

Table 6.6 Food outlets. Results of pollutants in wastewater. The values are

compared to the standards as stipulated in the Environmental Quality (sew-

age and industrial effluents) regulations, 1979. Figures in italic bold indicate

values exceeding the Standard A and figure in bold also exceed the Standard

B values.

Food

Centre

Restau-

rant

Coffee

Shop

Fast-

food

Market Stan-

dard A

Stan-

dard B

PH 6.8 6.2 8.0 7.9 6.0 6-9 5.5-9

BOD, mg/l 660 833 278 390 260 20 50

COD, mg/l 676 1,040 405 624 295 50 100

TSS, mg/l 372.0 268.0 90.7 220.0 110.0 50 100

NH4-N, mg/l 0.26 67.10 0.15 0.13 12.6

Tot-N, mg/l 8.34 0.43 1.84 16 26.5

Tot-P, mg/l 8.72 2.68 3.62 1.73 9.22

O&G, mg/l 124.0 2.14 12.0 155.0 17.8 n.d 10

The estimates of the discharge of pollutants are presented in Table 6.7. The

highest pollution load is discharged from the Padungan sub-catchment area fol-

lowed by Maong, Bintangor 3 and Bintangors.



95

Table 6.7 Food-outlets. Estimated loads of different pollutants from food out-

lets in the different catchment areas (kg/day).

Catchment BOD COD

TSS

Tot N

Tot P

South of Sg.

Sarawak

Bintangor-1 0 0 0 0 0

Bintangor-2 122.4 146 50 9 3

Bintangor-3 124 156 50 7 3

Padungan 153 192 62 8 3

Sekama 51 71 20 1 0

Sekama 1 4 6 2 0 0

Periok 11 16 4 0 0

Biawak 28.4 35 11 1 1

Bintawa 6 8 2 0 0

Bintawa 1 4 4 2 0 0

Kudei 10 13 4 0 0

Maong 131 171 52 5 2

North of Sg.

Sarawak

Gita 0.4 0 0 0 0

Laruh 0.4 0 0 0 0

Turong 0 0 0 0 0

Sinjan 7 8 3 0 0

Bedil 0 0 0 0 0

Gersik 0 0 0 0 0

Seman Lama 0 0 0 0 0

Siol Kandis 1 0 0 0 0 0


Total 651.4 827 263 33 12

6.4 Pollution from Industries

6.4.1 Types of Industries and Types of Pollutants

There are three main industrial estates in Kuching:

Pending Industrial Estate. This estate comprises industries of food proc-

essing, wood ,wood/cork processing, furniture manufacturing, chemical

products and plastic product processing;

Demak Laut Industrial Park at the north of the Barrage. This estate com-

prises industries of wood and wood/cork processing, furniture manufactur-

ing and food processing;

Sama Jaya Free Industrial Zone. This estate is dominated by electronics

industries.



96

In addition to the large industrial estates, small workshops (such as automobile

and garage shops) are distributed all over the city especially to the south of Sg.

Sarawak (Cf. Section 6.4.5, Table 6.10).

The industries generate a wide variety of pollutants. Table 6.8 provides an

overview of typical pollutants from different types of industries.

Table 6.8 Overview of types of wastewater pollutants produced by different

types of industries in Kuching.

Point Sources Type Pollutants Indicators

Workshops Repair Shops, Ga-

rages

Oil and Grease, Spent

Solvents, etc

pH, Oil and Grease, TSS,

Colour

Printing

Paper mill, News-

print

Spent solvents, wasted

ink

Colour, COD, TSS, Chlo-

rine, Chromium, Barium,

Silver

Food Processing

Noodles, Biscuit,

Seafood, Poultry,

Soy Sauce, Canning,

Beverages, etc

Wash water, Effluent

wastewater

pH, Oil & Grease, COD,

BOD, TSS, Nitrogen,

Phosphorus, Colour.

Rubber Processing Smoked Rubber

Sheet

Effluent Wastewater pH, TSS, BOD, COD,

Nitrogen

Metal Industry

Steel Manufacturing Spent acid, spent sludge,

rinse water

pH, COD, TSS, Oil and

Grease, Lead, Arsenic,

Zinc, Iron, Chromium,

Aluminium, Manganese

Aluminium Extru-

sion

pH, COD, TSS, Nickel,

Chromium III and V, Tin,

Lead, Aluminium, Sul-

phate

Galvanising (Zinc &

Nickel)

pH, COD, TSS, Nickel,

Chromium III and V, Iron,

Lead, Zinc

Electronics /

Semi-Conductors

Industry

Microchips, Printed

Circuit Board, etc

Spent Solvent, spent

acid, wash water

pH, COD, TSS, Lead,

Tin, Nickel, Copper, Zinc,

Cadmium, Selenium,

Arsenic, AOX.

Ceramic process-

ing

Floor Tile, Wall

Tile, Sanitary Fix-

tures

Wash water, effluent

wastewater

TSS, Colour, COD, Iron,

Lead, Zinc, Cadmium

Glue Manufactur-

ing

Adhesives for ply-

wood

Wash water, spillage pH, phenol, formalde-

hyde, urea, methanol

Batteries Manu-

facturing

Assembly of batter-

ies

Spent acid, spent

sludge/slurry

pH, TSS, COD, Lead,

Sulphate

Paint Industry

Water-base Paint,

Solvent Paint

Spent Solvent, Spent

Sludge, Rinse Water

pH, COD, TSS, Oil and

Grease, Lead, Nickel,

Copper, Zinc, Cadmium.



97

6.4.2 Estimated Number of Different Types of Industries

The SUD Project has estimated the number of different types of industries in

the twelve catchment areas, which are discharging to Sg. Sarawak upstream of

the barrage. This area includes only the industrial estate at Pending. The indus-

trial estates: Demak Laut Industrial Park and Semajaya Free Industrial Zone are

not included.

The results of the estimate are summarised in Table 6.9. The industries are

clearly concentrated in the Pending area (i.e. sub-catchment areas: Sekama 1,

Periok, Biawak, Bintawa, Bintawa 1). Most of the industries in the Pending

area are SMIs, which are engaged in food processing (baking, canning, bever-

age production, preserving of fish and crustacean); wood processing, printing

and metal works (aluminium extrusion, steel manufacturing and galvanising).

Table 6.9 Number of different types of Industries in different Sub-catchment

areas

Catchment Printing Food proc-

essing

Rubber

processing

Alumi-

nium

Steel Galvanis-

ing

South of Sg.

Sarawak




Padugan 2 - - - -

Sekama - - - - -

Sekama 1 1 2 1 - -

Periok 1 5 1 - -

Biawak 4 17 13 2 6 1

Bintawa 5 2 - 2 2 -

Bintawa 1 3 61 3 2 5 3

Kudei - - - - - -

Maong - 6 - - 5 2

North of Sg.

Sarawak

Gita - - - - - -

Laruh - - - - - -

Turong - - - - - -

Sinjan - - - - - -

Bedil - - - - - -

Gersik - - - - - -

Seman Lama - - - - - -

Siol Kandis 1 - - - - - -

Siol Kandis 2 - - - - - -

Total 16 93 18 6 18 6



98

Table 6.10 Number of different types of Industries in different Sub-

catchment areas.

Catchment Wood

process-

ing

Ceramic

process-

ing

Batteries

manu-

facturing

Paper

Mills

Work-

shops

Petrol

stations

Others

Bintangor 1 - - - - 2 1 3

Bintangor 2 - - - - 28 - 34

Bintangor 3 - - - - 23 - 24

Padugan 12 - - - 131 9 31

Sekama 1 - - - 113 1 1

Sekama 1 3 - - - 2 - 2

Periok 12 - - - 47 1 2

Biawak 8 2 2 1 22 - 2

Bintawa 10 - - - - - 3

Bintawa 1 49 - 2 - 11 - 7

Kudei 2 - - - 2 - 2

Maong 38 4 - - 135 14 53

Gita - - - - 3 1 4

Laruh - - - - 17 3 3

Turong - - - - 3 - -

Sinjan - - - - 2 1 8

Bedil - - - - - - 5

Gersik - - - - - - 3

Seman Lama - - - - - - 2

Siol Kandis 1 - - - - - - 1

Siol Kandis 2 - - - - - - -

Total 135 6 4 1 551 31 521


Many Industries would have a wastewater treatment system in place. However,

there are quite a few industries without any or insignificant wastewater treat-

ment. Presently, data on number of industries with a proper wastewater treat-

ment system and number of industries without is not available. An overview of

treatment facilities at the industries visited during the SUD field study is pre-

sented in the Volume 2 of the River Quality Baseline Study Report.


Currently, the enforcement with regards to compliance to the Environmental

Quality Act 1974 (EQA) Standards is carried out by the Department of Envi-

ronment (DOE) who conducts regular sample collection and analysis of the fol-

lowing industries:

Industries discharging more than 60 m3 wastewater per day or where the

total load of BOD in effluents exceed 6 kg per day;



99

Industries involved in processing of oil palm fruit; and

Industries involved in the processing of rubber.

The industries regulated by DOE only constitute a minor fraction of the total

number of industries situated in Kuching.

6.4.5 Estimated Total Load of Pollutants from Industries

The total load of different pollutants from different types of industries in the

twelve sub-catchment areas have been estimated based on results of the meas-

urements on wastewater from different types of outlets and the estimated num-

ber of different types of industries. Details are presented in Volume 2 of the

River Quality Baseline Study Report. The main findings are presented below.

It was found that the wastewater from the industries with treatment facilities

generally complies with the standards as stipulated in the Environmental Qual-

ity Regulation. This clearly showed at the visited cases for steel-, aluminium-,

galvanising-, rubber-, beverage- and seafood- industries as well as the slaugh-

terhouse. On the other hand, the wastewaters from the industries without treat-

ment systems significantly violate the standards especially for the parameters of

BOD, COD TSS, Oil & Grease. This is conformed to the case for the ceramic-,

the paint- and the printing industries.

The highest load is of pollutants from industries is unsurprisingly from the

catchment areas in Pending (Sekama1, Periok, Biawak, Bintawa, Bintawa 1)

followed by Padungan and Maong (Table 6.11).



100

Table 6.11 Industries. Estimated loads of different pollutants from industries

in the different catchment areas (kg/day).

Catchment BOD COD

TSS

Tot N

Tot P

South of Sg. Sara-

wak



Bintangor-3 0 0 0 0

Padungan 0.14 0.23 0.061 0.021 0.0084

Sekama 0 0 0 0 0

Sekama 1 0.26 0.74 0.53 0.12 0.0676

Periok 0.43 1.26 0.79 0.25 0.1606

Biawak 3.76 10.39 18.60 1.18 0.628

Bintawa 1.61 6.63 8.33 0.21 0.099

Bintawa 1 4.12 13.67 7.44 3.11 2.018

Kudei 0 0 0 0 0,00000

Maong 3.30 6.92 24.99 0.45 0.303

South of Sg. Sara-

wak

Gita 0 0 0 0 0

Laruh 0 0 0 0 0

Turong 0 0 0 0 0

Sinjan 0 0 0 0 0

Bedil 0 0 0 0 0

Gersik 0 0 0 0 0

Seman Lama 0 0 0 0 0



Total 13.62 39.85 60.75 5.33 3.285

6.5 Pollution from Agriculture

6.5.1 Types of Agricultural Activity and Types of Pollutants

One of the main sources of pollution from agriculture is from livestock farm-

ing, particularly from pig farms.

Based on the list from the NREB Livestock Unit, there are currently fifty-nine

pig farms within the Kuching, Serian, Bau and Samarahan regions. The stand-

ing pig population is about 61,000.

Pollutants, which have been chosen for indicators for pig farms, include BOD,

COD, TSS, Tot-N, Amm-N, Phosphorus, Faecal Coliforms and Total Coli-

forms.



101

Other sources of pollution from agriculture include oil palm plantations and

horticulture farms upstream of Kuching. Pollutants from these include nutrients

(fertilisers) and pesticides. At present, there is no available information on the

amount of agrochemicals used or discharged.


The wastewater from most pig farms in the Kuching area is treated in a two-

pond system, in which organic matter is digested by anaerobic bacteria in one

pond and by aerobic bacteria in the other. These ponds are normally con-

structed from earth and are generally rectangular in shape, with dimensions of

typically about 10m x 12m each for a farm with a standing pig population

(SPP) of about 1,000-2,000.

Farmers who do not have sufficient space for the two-pond system use other

treatment methods. Among the ones more commonly used are the solid-liquid

slurry separator machines which separates the solids from the liquids of the

wastewater from the pig farms. This technology is not very efficient in degrad-

ing organic matter.

None of the systems are very efficient. One major problem being that is the

sludge ultimately ends up in the river.


Currently the enforcement with regards to compliance to the Natural Resources

and Environment (Control of Livestock Pollution) Rules, 1996 is carried out by

the Natural Resources and Environment Board (NREB). NREB receives two

reports from licensed pig farms each year. The concentrations of BOD, COD

and TSS in the discharge must be reported and certain limits in three successive

phases must be complied with (Cf. Table 6.12). In addition, NREB carries out

their own sampling and analysis of water from the ponds at licensed and unli-

censed pig farms.

Table 6.12 Water quality standards for wastewater from pig farms

Permitted concentration in discharge from

existing farms

Phase 1 Phase 2 Phase 3

BOD, mg/l 1.300 250 50

COD, mg/l 2.500 1.000 500

TSS, mg/l 1.500 300 100

Permitted concentration in discharge from

new farms:

Phase 1 Phase 2 Phase 3

BOD, mg/l 500 250 50

COD, mg/l 2.500 1.000 500

TSS, mg/l 1.500 300 100



102

6.5.4 Pollutant Concentration in Wastewater from Pig Farms

Table 6.13 shows the results of NREB analysis of pond water from different pig

farms in the Kuching area. In most cases, the pig farms recorded marginally

comply with the Phase 3 discharge limit posed by the legislation (Cf. Table

6.12 and Table 6.13). Most of the farms however, comply with the Phase 2 dis-

charge limits.

Table 6.13 Results of NREB measurements of concentrations of BOD, COD

and TSS in water collected from wastewater ponds at pig farms upstream of

Kuching.

Standing Pig

Population

BOD (mg/l) COD (mg/l) TSS (mg/l)

1 89 69 69 123

2 80 0 0 0

3 2000 515 3400 500

4 200 45 164 55

5 1600 40 132 38

6 200 17 82 60

7 300 219 952 760

8 500 23 126 100

9 305 47 246 75

10 1220 59 278 135

11 150 10 10 10

12 800 169 636 300

13 150 23 74 230

14 1800 25 58 170

15 300 0 0 0

16 5000 120 354 158

17 1200 0 0 0

18 2000 31 60 180

19 200 117 224 130

20 1200 97 462 160

21 3200 137 434 105

22 2000 90 528 170

23 1500 30 108 65

24 3000 0 0 0

25 300 137 348 293

26 1100 11 58 320

27 500 51 60 45

28 1500 143 510 215

29 1500 51 278 105

30 na na na na

31 500 117 224 130

32 800 49 208 100

333 700 51 186 55

34 1200 33 74 590

35 300 25 70 40

36 280 39 222 120



103

Table 6.13 continued

Standing Pig

Population

BOD (mg/l) COD (mg/l) TSS (mg/l)

37 180 99 300 140

38 2500 105 264 118

39 150 35 202 80

40 350 507 1198 530

41 500 67 252 1350

42 3500 50 152 235

43 1000 16 72 21

44 1500 67 316 77

45 2500 75 126 75

46 1500 100 338 235

47 60 na na na

48 1500 16 84 98

49 300 59 124 86

50 800 219 952 760

51 800 168 374 165

52 800 89 302 210

53 500 62 274 85

54 300 18 174 12

55 1800 20 74 70

56 2500 26 214 95

There is no information on flow of wastewater from the pig farms. Therefore, it

is not possible to estimate the total load from the farms as for households, food

outlets and industries.

According to the NREB records, the standing pig population in the Kuching

area is about 61,000. According to Danish experience, one pig produces as

much as 200g BOD/day. This is 3-4 times more than the amount produced by

humans. The total amount of BOD produced by pigs in the Kuching area can

thus be estimated at some 12,000 kg BOD/day, which is of the same magnitude

as the amount of BOD estimated to be discharged from households in Kuching

(exclusive of the households in the Sg. Kuap catchment). Some reduction of

BOD levels takes place in the treatment ponds, consequently, the amount of

organic pollutants discharged to the river would be smaller than the 12,000 kg

BOD/day. However, it would seem that pig farms are the significant source of

pollution of organic and faecal bacteria to the river system.

6.6 Other Sources of Pollution

Other sources of pollution to the river include: Hospitals and clinics, shopping

centres, large commercial buildings, river vessels, port, dockyards and ship re-

pair areas along Sg. Sarawak. These sources are less importance compared to

those described above.



104

Hospitals and clinics

Hospitals and clinics generally have their own sewage treatment systems.

Clinical waste (infectious refuse, bodily parts and organs, blood supplies, trans-

fusion bags, disposable syringes, expired medicines, used chemicals, bandaging

materials, etc) is incinerated and is not discharged to the river.

Shopping centres, large commercial buildings and hotels

Large establishments such as shopping centres, which mainly comprise various

types of commercial businesses ranging from textile vendors, hairdresing sa-

loons, electronics shops produced varied liquid waste. Other than sewage from

the septic tanks, other types of waste which are water-based include chemicals

used in cleaning floors and windows, used aerosol cans, fluorescent tubes and

other mercury-containing waste, used batteries, solvents, ink residues, dyes, etc.

Most hotels have their own treatment systems. Many commercial buildings that

have their own treatment facilities (mostly septic tanks) are often inducing con-

siderable pollution problems locally, and often give rise to complaints from

neighbours due to the odour. The septic tanks are not regularly maintained and

as mentioned above, septic tanks are not very efficient even when they function

properly.

River vessels, port, dockyards and ship repair areas

Liquid waste from river vessels mainly oil and grease-based and is mostly pro-

duced onboard during machinery or engine servicing/maintenance works and

fuel refilling at the docks. Unused fuels are kept in metal drums and stored on

board the ships (for those with the capacity to do so) or at the docks. It is as-

sumed that used fuel is discarded off the vessels into drums and stored at the

docks or storage areas. Paint substances would be related to repair works con-

ducted at the dry docks.

Mining areas

Within the Kuching region, the main mining activities are associated with lime-

stone and sand mining (for the cement and construction industry) and loam/clay

mining for brick-production industry. These areas are located mostly south and

south-west of the city towards Bau-Serian areas. In Bau, there are abandoned

gold mines and presently no active ones. There is presently no record of any

mining waste within Kuching City. From the limestone and loam/clay mining

activity, the types of waste generated would mainly be solid waste in the form

of fine dust and debris, soil erosion effects and sedimentation into waterways

and nearby streams/rivers. There are indications that sediments polluted by

heavy metals in the gold mining areas in the past that may be transported down-

stream of the river (Cf. Section 5.3)



105

INSERT NEW MAP FROM DAYA RANCANG

Fig 6.2. Location of housing schemes connected to centralised treatment systems and commercial buildings, government buildings, hospitals, ho-

tels etc, with own treatment systems.



106

6.7 Other Sources of River Quality Deterioration

In addition to the discharge of pollutants, the spillage and discharge of soil due

to logging, dredging and transportation of sand by barges and construction of

roads and highways and landclearing for plantation and urban projects are po-

tentially affect the river quality. In addition, the presence of the barrage may

have a deleterious impact on the river quality.

Logging activity

Most logging activities operated upstream are located far from the Sg. Sarawak

catchment, therefore, impacts from such activity is minimal, if any. There may

be logging activities at the areas bordering Kalimantan, however at this stage,

there is no record available. For the State of Sarawak, the most affected river

systems are those located towards the north and north-east, i.e. Batang Rajang

in Sibu and Sg. Baram in Miri. Logging activities would generally impact river

water quality in terms of the accumulation of runoff from soil erosion forming

sediments, which flow into the streams, rivers and existing waterways.

Transportation of extracted sand by barges downstream

Extraction of sand from the riverbed and transportation of the sand is one of the

potential contributers to increase in sedimentation levels in the river. This is

mainly due to small spillage, which occurs during extraction from the river bot-

tom and during travelling from the extraction point to the final destination, lo-

cated further downstream and/or outside of the barrage area. Wind-blown sand

for instance from the uncovered top of the sand-carrying barrage would settle

onto the river banks and river bed at any location along the river during the oc-

currence of strong winds and in time, the cumulative effect would be such that

sediment levels will rise at these locations.

Construction of roads, clearing for plantations and urban development

Construction of roads, clearing for plantations and urban development located

along tributaries of Sg. Sarawak or along Sg. Sarawak itself has the potential

contributing sedimentation of soil runoff due to surface erosion from rainfall

effects. The construction of the Borneo Heights Road Project, for example,

which approximately 25 km and located close to the upstream tributaries of Sg.

Sarawak Kiri (Sg. Abang, Sg. Semadang and Sg. Temurang), would have also

contributed to the potential increase in sedimentation in the streams and even-

tually in the river. Runoff from the construction areas reaches the tributary

streams via a network of roadside and cascading drain system installed for the

road project. Another recent project is work-in-progress of the road built almost

parallel to the Sg. Sarawak northern bank, i.e. Petra Jaya region. The construc-

tion of this road would presumably has some impacts on the sedimentation lev-

els of the river, particularly in relation to surface runoffs during rainfall.

Effect of the Barrage

Kuching Barrage Management is currently operating a flushing scheme to miti-

gate environmental impacts of the barrage. Potential impacts, which are miti-



107

gated by the flushing scheme, are discussed in various previous sections. They

are:

Reduction of saltwater intrusion and river flow velocity;

Increase of sedimentation of suspended matter due to reduction of flow ve-

locities

Increased risk of oxygen depletion and accumulation of organic material,

nutrients and bacteria upstream of the barrage;

Risk of impacts on mangroves and nipah forests due to the decreased salin-

ity;

Risk of reduction of the stock of the giant freshwater prawn which is an

important commercial species, due to blocking of migration routes to and

from spawning and nursery grounds downstream of the barrage; and

Reduction of the population and catch of marine and brackish water species

fish in the river due to reduced salinity.

Should the flushing scheme for some reason be inadequate in the future, there

is a risk that measures to improve the water quality may be affected by the

presence of the barrage. The interpretations of state indicators in the EMS

should therefore always be related to the operation of the barrage.



108

7 Discussion and Conclusion

7.1 Degree of Pollution

The baseline study has documented that the tributaries of Sg. Sarawak situated

in Kuching City and Sg. Sarawak fronting Kuching are significantly polluted.

The major problems are serious pollution with faecal-derived coliform bacteria

and pollution with organic matter, leading to oxygen deficiency, deleterious

impact on bottom fauna and offensive odour. The source of the pollution is un-

treated and insufficiently treated sewage and wastewater, which is discharged

directly to the open drains in the city.

The water qualities of different zones of the entire river system have been clas-

sified according to the Malaysian Interim National Quality Standards

(INQWS). A summary of the results of classification is presented below.

The water qualities in the tributaries Sg. Maong, Sg. Bintangor, Sg. Padun-

gan Sg.Sekama and Sg. Tabuan in the city are very poor and fall between

class IV and class V of the INWQS standards.

The water quality in the stretch of the main Sg. Sarawak Proper. The water

can be classified as class III in terms of physico-chemical parameters.

However, in terms of bacteriological parameters, the water is only class V.

The water quality in Sg. Sarawak upstream of Kuching, including Sg. Sa-

rawak Kiri and Kanan is quite good and generally complies with class

IIA/IIB in terms of physico-chemical parameters. However, the water does

not meet the class IIB standards for faecal-derived bacteria.

7.2 Sources

From the results of the pollutant load estimation exercise carried out for house-

hold, food outlets and industry in the previous section, a comparison of their

combined yearly loading were made to assess their respective contribution to

the pollutant load of Sg. Sarawak and tributaries.

Table 7.1 presents an overview of the estimated total loads of pollutants to Sg.

Sarawak and tributaries from households, food outlets, industries and others.



109

Untreated sewage from households is identified as the most significant source

of pollution as a whole. The loads of BOD, COD, TSS, Tot-N, Tot-P and oil

and grease from households are orders of magnitude larger than the loads from

food outlets (markets, food centres, restaurants etc.), industries and other

sources.

Food outlets (restaurants, markets etc.) are, however, the significant local

source of pollution in the central business centre immediately south of Sg. Sa-

rawak. In sub-catchment areas Bintangor 2, Bintangor 3, Padungan, Periok and

Biawak, 20-40% of the BOD load and as much as 71-83% of the load of oil and

grease are discharged from food outlets. In Sekama and Bintawa, 83 and 71%

of the oil and grease are from food outlets (Table 7.3, 7.4 and Fig. 7.1).

Presently, the Local Councils spend huge resources in these areas cleaning the

oil and grease in the drains downstream of food outlets due to inadequate

treatment facilities at the food outlets.


different types of sources in Kuching. (Rounded figures)

Households Food outlets

(Markets, Food cen-

tres, Restaurants etc)

Industries

BOD kg/day 5900-9700 650 15

COD kg/day 19900-26000 800 40

TSS kg/day 5400-8000 260 60

Tot-N kg/day 2600-3400 30 5

Tot-P kg/day 500-600 10 3

Oil & grease kg/day 200-350 60 2

Pb kg/day - - 0.02

Cd kg/day - - 0.002

Cu kg/day - - 0.01

Zn kg/day - - 0.7

Fe kg/day - - 0.9

Mn kg/day - - 0.07

Al kg/day - - 0.9

AOX kg/day - - 0.009



110

Table 7 2 Percentage of total load of BOD from households, food outlets and

industries in each of the 21 sub-catchment areas discharging to Sg. Sara-

wak.The shadings indicate areas where food outlets are contributing signifi-

cantly to the total load.

Catchment Households

% of

total load from the

three types of sources

in the sub-catchment

area

Food outlets

% of

total load from the



area

Industries

% of

total load from the



area

South of Sg. Sara-

wak

Bintangor-1 100 0 0

Bintangor-2 67 33 0

Bintangor-3 61 39 0

Padungan 79 20 1

Sekama 100 0 0

Sekama 1 98 0 1

Periok 69 28 3

Biawak 75 21 4

Bintawa 89 9 2

Bintawa 1 97 1 2

Kudei 97 3 0

Maong 96 3 1

North of Sg. Sara-

wak

Gita 100 0 0

Laruh 100 0 0

Turong 100 0 0

Sinjan 98 2 0

Bedil 100 0 0

Gersik 100 0 0

Seman Lama 100 0 0

Siol Kandis 1 100 0 0




111

Table 7.3 Percentage of total load .Oil and grease from households, food out-

lets and industries in each of the 21 sub-catchment areas discharging to Sg.

Sarawak.The shadings indicate areas where food outlets are contributing

significantly to the total load.

Catchment Households

% of

total load from the



area

Food outlets

% of

total load from the



area

Industries

% of

total load from the



area

South of Sg. Sara-

wak

Bintangor-1 100 0 0

Bintangor-2 17 83 0

Bintangor-3 9 91 0

Padungan 29 71 0

Sekama 17 83 0

Sekama 1 56 44 0

Periok 20 80 0

Biawak 21 79 0

Bintawa 30 70 0

Bintawa 1 87 13 0

Kudei 76 24 0

Maong 70 30 0

North of Sg. Sara-

wak

Gita 100 0 0

Laruh 100 0 0

Turong 100 0 0

Sinjan 82 18 0

Bedil 100 0 0

Gersik 100 0 0

Seman Lama 100 0 0





112

Figure 7.1. Areas in Kuching City where more than 70% of the total load of oil

and grease is discharged from food outlets (in green).



113

Table 7.4 and 7.5 indicate the total loads of pollutants from the different sub-

catchment areas (sum of load from all sources in each area).

The load of organic pollution (BOD, COD, TSS, Tot-N, Tot-P and O&G) is the

highest from the Maong sub-catchment area followed by Padungan, Bintawa1

and Seman Lama (Table 7.4).

The highest loads of heavy metals are encountered in the Pending area (Sekama

1, Periok, Biawak, Bintawa, Bintawa 1), Padungan and Maong. However, it is

noted that the load estimate only includes loads from industries. There are no

information of concentrations of heavy metals in outlets from households, food-

outlets, workshops and other sources. The load from these sources might actu-

ally exceed the load from the industries, due to the sheer number of sources.


different sub-catchment areas in Kuching.(Rounded Figures). The shading

indicates the four highest loads for each parameter.

Catchment BOD

kg/day

COD

kg/day

TSS

kg/day

Tot-N

kg/day

Tot-P

kg/day

O&G

kg/day

Bintangor-1 100-200 350-530 100-170 50-70 9-11 3-7

Bintangor-2 320-420 750-950 230-300 90-120 22-23 19-20

Bintangor-3 290-420 650-900 170-270 100-120 33-37 13-20

Padungan 670-880 1700-2100 500-655 200-270 54-55 37-40

Sekama 150-220 370-500 100-150 45-60 10-12 9-11

Sekama 1 60-100 190-280 55-90 30-40 5-6 2-4

Periok 30-40 80-100 20-30 9-12 2 2

Biawak 100-160 280-390 100-140 40-50 9-11 5-7

Bintawa 40-80 130-200 40-70 20-30 3-4 1-4

Bintawa 1 300-540 960-1,400 280-460 150-190 26-33 7-19

Kudei 270-380 760-1,000 230-315 100-130 23 13-14

Maong 2,800-4,400 8,300-11,400 2,500-3,600 1,100-1,500 220-250 120-155

Gita 200-400 700-1,000 200-340 100-140 18-23 5-13

Laruh 170-270 520-720 155-230 70-95 14-16 7-9

Turong 40-60 120-160 40-50 15-20 3-4 2

Sinjan 300-480 900-1,280 270-400 130-170 24-28 11-17

Bedil 230-400 750-1,100 220-350 110-145 19-24 7-14

Gersik 70-100 200-300 60-95 30-40 5-7 2-4

Seman Lama 340-500 1,000-1,380 300-440 140-180 28-30 15-17

Siol Kandis 1 180-340 590-900 170-290 90-120 15-19 4-11

Siol Kandis 2 15-25 50-70 15-20 5-10 1 1



114


different sub-catchment areas in Kuching.

Catchment Pb

g/day

Cd

g/day

Cu

g/day

Zn

g/day

Fe

g/day

Mn

g/day

Al

g/day

AOX

g/day

Bintangor-1 0 0 0 0 0 0 0 0

Bintangor-2 0 0 0 0 0 0 0 0

Bintangor-3 0 0 0 0 0 0 0 0

Padungan 0 0 0 0.3 2 0.1 2 0

Sekama 0 0 0 0 0 0 0 0

Sekama 1 0.3 0.02 0 1 20 2 10 0.2

Periok 0.7 0.04 0 2 30 3 1.6 0.2

Biawak 4.0 0.5 0.2 200 300 20 300 3

Bintawa 0.4 0.07 0 0 40 3 100 1

Bintawa 1 10 0.9 0 100 300 30 100 2

Kudei 0 0 0 0 0 0 0 0

Maong 2 0.2 0.4 0.4 100 7 400 1

Gita 0 0 0 0 0 0 0 0

Laruh 0 0 0 0 0 0 0 0

Turong 0 0 0 0 0 0 0 0

Sinjan 0 0 0 0 0 0 0 0

Bedil 0 0 0 0 0 0 0 0

Gersik 0 0 0 0 0 0 0 0

Seman Lama 0 0 0 0 0 0 0 0

Siol Kandis 1 0 0 0 0 0 0 0 0

Siol Kandis 2 0 0 0 0 0 0 0 0



115

7.3 Existing Technical Measures to Reduce Pollution Loading

In general, there is no technical means currently imposed to reduce pollutant

load, for households. Most households discharge greywater directly to the

stormwater drains and probably the only measure to reduce contaminants from

entering the drains is the usage of coarse filtering equipment or apparatus in-

stalled at their washing sinks or wash basins.

Houses are generally equipped with septic tanks for treatment of blackwater,

but they are not well functioning due to inadequate desludging. A programme,

however, was launched to enforce the Rule of “Compulsory desludging of sep-

tic tanks, 1988” gazetted 15th October 1998, which specifies that every septic

tank in the city must be desludged every second year.

However, it must be stressed that even if all septic tanks in Kuching were

desludged regularly and functioning properly, the effect in terms of reducing

the pollution load to the tributaries and main river will still be insignificant.

Consequently, the sewage from the houses does not comply with the standards

as stipulated in the Environmental Quality (Sewage and Industrial Effluents)

Regulation, 1979.

Most of the food outlets also discharge wastewater directly to the drains. Some

of them do have treatment measures for physical filtration and removal of

heavy oil and grease residue (grease traps) in place. However, the grease traps

are generally not functioning, because they are not emptied and even in the case

they are actually emptied, it seems that this generally takes place in the drain

downstream of the trap.

At present, information on the numbers of food outlets with treatment facilities

is not available.

In general, the sewage from food outlets does not comply with the standards as

stipulated in the Environmental Quality (Sewage and Industrial Eeffluents)

Regulation, 1979.

Many industries have their wastewater treatment system in place. However,

there are a few industries without any wastewater treatment. Presently, data on

the number of industries with and without proper wastewater treatment ssystem

is not available.

In the SUD field study, it was generally observed that the industries equipped

with proper treatment facilities complied with the regulations, whereas those

without or with inadequate facilities did not.



116

7.4 Existing Control and Enforcement Measures

The enforcement measures are generally passive, i.e. only in case of com-

plaints, authorities carry out inspections and may impose a fine to the offender.

There is currently no specific active enforcement measure carried out by the

authorities to control the discharge of sewage from households and/or food out-

lets. Other than cleanliness campaigns and awareness programmes, no direct

inspection or regular checks on the discharge has been made.

The Department of Environment (DOE) is monitoring the wastewater from a

small fraction of the industries in Kuching for compliance to the Environmental

Quality Act 1974 (EQA). The monitored industries include: industries dis-

charging more than 60 m3 wastewater per day or where the total load of BOD

in effluents exceed 6 kg per day, industries involved in processing of oil palm

fruit and industries involved in the processing of rubber.

NREB is regulating the outlets from pig farms and other livestock activities.

7.5 Assessment of Preliminary Indicators

One of the important objectives of the river quality baseline study has been to

assess the suitability of the selected preliminary indicators for river quality in

the EMS for Kuching.

The baseline study has indicated that:

Some of the selected preliminary indicators are not suitable as indicators;

Some of the preliminary indicators should be modified; amd

Some new indicators should be added.

The proposed modifications of the preliminary indicators and the rationale for

the modifications are presented in the following.

7.5.1 State Indicators


Preliminary indicators proposed not to be included in the EMS

The baseline study has clearly showed that concentrations of heavy metals in

surface water are not suitable as indicators for water quality of the river.

The levels of the heavy metals Hg, Pd, As, Zn, Cd, Cr, Cu and Ni in water

measured in NREBs‟ water quality monitoring of the Sg. Sarawak system are

generally very low and below the detection limits even in the very polluted

tributaries. It is a worldwide experience, that dissolved heavy metals are gener-

ally encountered in very low levels in surface water and that analytical detec-

tion limits are sometimes higher than natural levels. The reason for the low lev-



117

els of dissolved heavy metals in even very polluted areas is that most trace ele-

ments are readily adsorbed onto particulate matter, which is subject to sedimen-

tation. Data on heavy metals in sediments are therefore, more suitable as indi-

cators because discharged metals are accumulated in the sediments (Cf. below).

The general low levels of dissolved trace elements also make it very difficult to

measure concentrations correctly, as there is a high risk of contamination dur-

ing sampling, pre-treatment and storage. Therefore, there is a high risk that an

observed increase in concentration between two sampling rounds may be due to

a slight contamination of the sample and not a real increase.

The same problems may be encountered for PAHs and Total Petroleum Hydro-

carbons.

The levels of Fe and Mn in water measured in NREBs‟ water quality monitor-

ing of the Sg. Sarawak system are generally very high also in areas not affected

by human activities.

The high iron and manganese concentrations are due to natural processes and

not primarily a result of human activities, although discharge of wastewater

may contribute to increased levels. Results from 1999 indicates that the concen-

trations of iron in Sg. Sarawak Kiri are at the same level as those encountered

in the heavily polluted Sg. Maong and higher than the levels in Sg. Sarawak

main fronting Kuching.

High background concentrations in surface water are common in natural wa-

ters. Leaching of iron is particularly significant in swampy areas such as fresh-

water swamps, nipah forests and mangroves, which are abundant in the Sg. Sa-

rawak catchment area. The soils in such areas are waterlogged and anaerobic.

In the anaerobic, waterlogged soil, the solubility of iron increases. Insoluble

Fe+++ is reduced to soluble Fe++, which is then transported via groundwater to

the river. The solubility of manganese increases in anaerobic swampy area in

the same way as iron does.

Occurrences of Fe and Mn in ground and surface waters are very much depend-

ent on environmental conditions, especially oxidation and reduction have re-

sulted in that Fe and Mn are not included in many priority lists or water quality

standards, internationally.

Based on the above considerations, it is therefore proposed that the following

preliminary indicators for surface water quality are not to be included in the

EMS for Kuching: Hg, Pd, As, Zn, Cd, Cr, Cu, Ni, Fe, Mn, Polyaromatic hy-

drocarbons (PAH) and total petroleum hydrocarbons (TPH).



118

Indicators proposed to be included in the EMS

The baseline study has confirmed that the following preliminary indicators for

water quality are suitable and are therefore proposed to be included in the EMS

for river quality:

pH, DO;

BOD, COD, TSS;

Nutrients (Ammoniacal Nitrogen (NH4-N), Nitrates, Phosphorous); and

Bacteria (Faecal coliforms and total coliforms).

Sediment quality


As outlined above, Fe and Mn are not suitable as indicators for the river quality

because natural processes may result in the discharge of very large quantities of

Fe and Mn not associated with human activities. These two metals finally end

up in the sediment. It is therefore, proposed that Fe and Mn are not included in

the indicators for sediment quality.


The baseline study has confirmed that the following preliminary indicators for

sediment quality are suitable and are therefore, proposed to be included in the

EMS for river quality:

Nutrients (Ammoniacal Nitrogen (NH4-N), Nitrates);

Heavy metals (Hg, Pb, AS, Zn, Cd, Cr, Cu, Ni);

CN; and

Oil and grease, Polyaromatic Hydrocarbons, PAH, Total Petroleum Hydro-

carbons (TPH).

In the preliminary indictors, phosphorous is included. However, the type of

phosphorous is not specified. It is proposed that Tot P is measured (Cf. below).

It is further proposed to add the following parameters, which were not proposed

during the selection of preliminary indicators:

Loss on ignition; and

Total N.



119

The reason for proposing these parameters is than the baseline study has indi-

cated that one of the major pollution problems of Sg. Sarawak is the discharge

of organic matter. Loss on ignition is a measure of the organic matter content of

the sediment. Total N and Total P are measures of all forms of N and P found

in the sediment, including that incorporated in dead organic matter, irrespective

of the chemical form (ammonium, nitrate, etc) which is highly dependent on

redox processes in the sediment as well as biological activity.

Pollutants in aquatic organisms

The most suitable organisms for monitoring purposes are molluscs. The base-

line study has indicated that it may be difficult or impossible to collect suffi-

cient amounts of molluscs for monitoring in Sg. Sarawak and the tributaries in

Kuching. However, molluscs transplanted in cages can be used.


It is proposed that transplanted mollucs be measured in their tissues for the

concentration of the following polutants:

Heavy metals (Hg, Pb, As, Zn, Cd, Cr, Cu, Ni and organotin); and

Polyaromatic Hydrocarbons, PAH, Total petroleum hydrocarbons (TPH).

The feasibility of this approach must be assessed from a pilot study.

Ecological parameters

Diversity index, species of fish of yy family and species of invertebrates of zz

family have been chosen as preliminary indicators.


It is proposed not to use “Invertebrates of zz family” as indicators because even

in the unpolluted state the part of Sg. Sarawak running through Kuching will

not house the families of invertebrates which are clear indicators of the unpol-

luted state. These families are typically encountered further upstream of the

river system where the river is narrower and flowing faster.


It is proposed to apply the Pearson and Rosenberg 1978 method of assessment

of pollution impacts on benthos in which number of species and abundance (no

individuals/m²) and species composition to be used as indicators. This method

has been used in the baseline study (described in detail in Volume 3).

It is proposed that the diversity of benthic macroinvertebrates be used as indica-

tor (Shannon Wiener diversity index).

It is proposed that catch per unit effort (cpu) of all fish and prawn species in a

catch to be used as indicators. Catch per unit effort is a standard measure of ef-

fort (including fishing time, length of net etc, dependent on fishing method).



120

Cpu of giant prawn (Macrobrachium rosenbergii) and the fish species Mystus

spp. and Oxyeleotris marmorata are also proposed as indicators. These species

are the commercially most significant species in Sg. Sarawak.

Aeasthetics

The preliminary indicators chosen are proposed to be included in the EMS. i.e.

Estimated volume of floatables collected from Sg. Sarawak; and

Level of smell by using standard method.

The baseline study has shown that the internationally recognised standard

method using the Threshold Odour Number is a good method.

In addition, the number of complaints of smell in river, drains and tributaries

should be used as indicators as well.

7.5.2 Load Indicators

It is proposed that all preliminary load indicators be used in the EMS. In addi-

tion, it is proposed that estimates of loads from households, food outlets and

industries to be used applying the methods used in the baseline study.



121

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wak

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Development Corporation (S) Sdn. Bhd. Sarawak



126

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2000, 16-18 October 2000, Ipoh, Perak, Malaysia



127

APPENDIX 1

WATER QUALITY DATA



128

Table 1. Water quality parameters Zone A (Sg. Sarawak Kanan) 1999. Mean of three sampling sites. Wet season: Nov-Feb. Dry season:

Mar-Oct.

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Mean Mean

Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry

No. of Samples Analysed 3 3 3 3 3 3 3 3 3 3 3 3 3 3

pH Value - 6,9 6,9 7,0 7,1 6,9 7,2 6,9 6,8 6,9 7,0

Dissolved Oxygen mg/kg - 5,4 4,3 3,0 3,8 4,9 7,2 5,9 6,2 6,0 4,8

Biochemical Oxygen Demand mg/kg - <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0

Chemical Oxygen Demand mg/kg - 13,1 2,0 4,0 9,6 11,3 35,9 19,7 12,5 16,1 12,6

Total Suspended Solids mg/kg - 30,8 8,3 30,4 12,0 24,2 27,0 32,0 26,7 29,3 22,1

Ammoniacal Nitrogen mg/kg - 0,07 0,10 0,10 0,08 0,08 0,15 0,10 0,17 0,1 0,1

Faecal Coliform Count (MPN/100mL)- 7800 2067 1267 8000 6633 11667 5000 7333 6167 6239

Total Colifom Count (MPN/100mL) 16000 6433 8000 11667 7333 11667 8667 12333 10500 10183



129

Table 2. Water quality parameters Zone A (Sg. Sarawak Kanan) 2000. Mean of three sampling sites. Wet season: Nov-Feb. Dry

season: Mar-Oct.

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average



pH Value 6,7 6,3 7,2 7,2 6,8 6,9 6,8 6,9 6,5 7,0

Dissolved Oxygen mg/kg 7,3 3,8 6,8 7,3 7,5 7,4 3,9 3,9 6,0 6,1

Biochemical Oxygen Demand mg/kg 0,4 0,3 0,2 1,3 0,3 0,4 0,6 0,6 0,52 0,6

Chemical Oxygen Demand mg/kg 7,3 5,5 4,6 10,9 3,5 4,7 9,5 8,4 6,78 6,9

Total Suspended Solids mg/kg 43,0 69,7 3,7 26,0 18,3 20,1 1,5 9,3 24,0 13,2

Ammoniacal Nitrogen mg/kg 0,05 0,05 0,20 0,10 0,05 0,05 0,10 0,1 0,08 0,1

Faecal Coliform Count (MPN/100mL) 1367 6333 800 6867 16000 7300 1067 7133 3850 6528




130

Table 3. Water quality parameters Zone B (Sg. Sarawak Kiri) 1999. Mean of two sampling sites. Wet season: Nov-Feb. Dry season:

Mar-Oct.




pH Value 7,0 7,1 6,7 6,9 7,1 7,1 6,9 7,1 7,3 7,1 6,9 6,7 6,9 7,0

Dissolved Oxygen mg/kg 3,5 3,7 2,8 2,6 4,5 2,9 1,9 9,6 - 7,4 7,1 6,9 5,3 4,5

Biochemical Oxygen Demand mg/kg <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0

Chemical Oxygen Demand mg/kg <6.0 <6.0 27,0 12,0 10,0 6,0 6,0 16,0 12,0 21,0 16,0 19,0 17,5 13,8

Total Suspended Solids mg/kg - - - - 31,4 126,5 28,4 128,0 - 121,5 132,4 33,0 82,7 87,1

Ammoniacal Nitrogen mg/kg <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1

Nitrate mg/kg <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Mercury mg/kg - - <0.0002 - <0.0002 - - <0.0002 - - <0.0002 - <0.0002 <0.0002

Lead mg/kg - <0.02 <0.02 - <0.02 - - <0.02 - - <0.02 - <0.02 <0.02

Arsenic mg/kg - <0.001 <0.001 - 0,006 - - <0.001 - - <0.001 - <0.001 <0.001

Zinc mg/kg - <0.01 <0.01 - <0.01 - - 0,02 - - 0,02 - 0,01 0,01

Cadmium mg/kg - <0.001 <0.001 - <0.001 - - <0.001 - - <0.001 - <0.001 <0.001

Chromium mg/kg - <0.001 <0.001 - <0.001 - - <0.001 - - <0.001 - <0.001 <0.001

Copper mg/kg - <0.01 <0.01 - <0.01 - - <0.01 - - <0.01 - <0.01 <0.01

Iron mg/kg 0,95 0,56 1,39 1,2 1,03 0,65 1,09 1,16 - 0,7 1,56 6,05 2,28 1,03

Manganese mg/kg - 0,86 0,43 - 1,31 - - 1,5 - - 0,94 - 0,90 1,08

Faecal Coliform Count (MPN/100mL) - - - - 6000 3000 4500 370 - 6000 4500 3700 4100 3974

Total Colifom Count (MPN/100mL) - - - - >16000 10500 9200 9500 - >16000 9500 9200 9350 12240



131

Table 4. Water quality parameters Zone B (Sg. Sarawak Kiri) 2000. Mean of two sampling sites. Wet season: Nov-Feb. Dry season:

Mar-Oct.




pH Value 6,9 6,7 7,2 7,1 7,0 6,9 7,0 7,0 6,8 7,0






Nitrate mg/kg <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Mercury mg/kg <0.0002 <0.0002 - - <0.0002 <0.0002 <0.0002

Lead mg/kg <0.02 <0.02 - - <0.02 <0.02 <0.02

Arsenic mg/kg <0.001 <0.001 <0.001 <0.001 <0.001

Zinc mg/kg 0,01 <0.01 - - 0,02 0,01 0,01

Cadmium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001

Chromium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001

Copper mg/kg <0.01 <0.01 <0.01 <0.01 <0.01

Iron mg/kg 1,13 0,34 0,8 0,65 0,65 0,38 0,54 0,97 0,74 0,67

Manganese mg/kg 0,05 0,01 0,02 0,01 0,03 0,01 0,02 0,03 0,03 0,02

Faecal Coliform Count (MPN/100mL) 2750 9200 2650 8450 16000 2950 8012 16000 5975 9010




132

Table 5. Water quality parameters Zone C (main Sg. Sarawak from Batu Kawa bridge to upstream of Satok bridge) 1999. Mean of

two sampling sites. Wet season: Nov-Feb. Dry season: Mar-Oct.



No. of Samples Analysed 2 2 2 2 2 2 2 2 2 2 2

pH Value 7,1 7,1 6,7 7 7,1 7,2 7,2 6,9 7,4 6,8 6,9 6,8 7,0 7,0

Biochemical Oxygen Demand mg/kg <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0

Chemical Oxygen Demand mg/kg 6 6 13 9 8 10 13,0 22 39 31 22 7 10,25 18,1

Ammoniacal Nitrogen mg/kg <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1

Nitrate mg/kg <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Mercury mg/kg <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Lead mg/kg <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

Arsenic mg/kg 0,004 0,003 0,004 0,003 0,019 0,005 0,006 0,001 0,005 0,006 0,002 0,003 0,003 0,006

Zinc mg/kg <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Cadmium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.01

Chromium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Copper mg/kg <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Iron mg/kg 0,90 0,55 0,56 0,81 0,56 0,58 1,04 1,28 0,85 0,83 0,86 0,61 0,73 0,81

Manganese mg/kg 0,02 0,04 0,02 0,06 0,11 0,04 0,04 0,04 0,04 0,03 0,03 0,02 0,03 0,05

Total Colifom Count (MPN/100mL) 9200 3500 1600 5400 9200 17000 1700 5400 5400 3500 3500 5400 5400 6150



133

Table 6. Water quality parameters Zone C (main Sg. Sarawak from Batu Kawa bridge to upstream of Satok bridge) 2000. Mean of

two sampling sites. Wet season: Nov-Feb. Dry season: Mar-Oct.



No. of Samples Analysed 2 2 2 2 2 2 2 2 2 2 2

pH Value 6,7 6,9 6,9 6,9 6,7 6,9 6,9 6,9 7,1 6,9 6,8 6,9

Biochemical Oxygen Demand mg/kg <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0

Chemical Oxygen Demand mg/kg 18 14 8 9 15 32 35,0 19 22 21 19,3 20,1

Ammoniacal Nitrogen mg/kg <0.1 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1

Nitrate mg/kg <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Mercury mg/kg <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Lead mg/kg <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

Arsenic mg/kg 0,005 0,002 0,008 0,002 0,004 0,002 0,004 0,004 0,004 0,003 0,004 0,004

Zinc mg/kg <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Cadmium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.01

Chromium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Copper mg/kg <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Manganese mg/kg 0,71 0,66 0,72 0,60 0,65 0,79 3,91 0,75 0,60 0,80 0,69 1,10

Total Colifom Count (MPN/100mL) 9200 1600 1800 5400 9200 920 1800 2400 3500 1600 5400 3328



134

Table 7. Water quality parameters Zone D (main Sg. Sarawak from Satok bridge to downstream of barrage) 1999. Mean of five/six

sampling sites. Wet season: Nov-Feb. Dry season: Mar-Oct.



No. of Samples Analysed 5 5 5 5 5 6 6 6 6 6 6 6

pH Value 6,8 6,6 6,7 7,0 7,2 7,0 7,3 7,0 7,0 7,1 6,8 6,7 7,0

Dissolved Oxygen mg/kg 3,1 5,2 5,0 3,0 2,5 3,8 2,6 6,4 4,3 5,6 4,6 4,3 4,1

Biochemical Oxygen Demand mg/kg 1,0 2,0 3,1 1,1 1,3 0,7 1,3 1,5 0,7 0,4 0,2 1,1 1,2

Chemical Oxygen Demand mg/kg 14,5 12,4 12,4 10,6 27,7 22,3 24,9 5,4 8,3 7,0 5,3 10,7 14,8

Total Suspended Solids mg/kg 16,0 12,1 29,6 16,0 10,9 18,7 21,2 33,7 61,7 30,8 47,7 25,3 27,8

Ammoniacal Nitrogen mg/kg 2,56 0,11 0,16 11,2 0,10 0,08 0,13 0,17 0,17 0,16 0,10 0,9 1,5

Nitrate mg/kg <0.5 <0.5 <0.5 <0.5 <0.5 1,20 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Mercury mg/kg <0.0002 <0.0002 <0.0002 <0.0002 0,0012 <0.0002 0,0002 0,0003 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Lead mg/kg 0,02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

Arsenic mg/kg 0,004 0,003 0,002 0,006 0,012 0,022 0,003 0,019 0,009 0,007 0,003 0,003 0,010

Zinc mg/kg <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0,02 0,01 0,02 0,02 0,01 0,01 0,02

Cadmium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Chromium mg/kg <0.001 <0.001 <0.001 0,001 0,001 0,002 0,001 <0.001 0,001 <0.001 <0.001 <0.001 <0.001

Copper mg/kg <0.01 <0.01 <0.01 <0.01 0,02 <0.01 0,03 0,01 <0.01 <0.01 <0.01 <0.01 <0.01

Iron mg/kg 0,79 0,92 0,73 0,59 0,92 0,57 0,91 0,61 0,96 1,03 1,09 0,933 0,790

Manganese mg/kg 3,00 1,07 0,68 9,82 135,55 110,29 152,40 105,37 52,56 11,22 8,85 4,307 72,24

Faecal Coliform Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000

Total Colifom Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000



135

Table 8. Water quality parameters Zone D (main Sg. Sarawak from Satok bridge to downstream of barrage) 2000. Mean of five/six

sampling sites. Wet season: Nov-Feb. Dry season: Mar-Oct.




pH Value 6,5 6,4 7,0 7,0 6,9 7,0 7,0 6,7 6,5 6,9






Nitrate mg/kg 0,20 0,06 0,16 0,18 0,21 0,21 0,39 0,33 0,1 0,2

Phosphorus mg/kg 0,23 0,12 0,12 0,13 0,16 0,20 0,34 0,10 0,2 0,2

Mercury mg/kg <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Lead mg/kg <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

Arsenic mg/kg 0,002 0,002 0,025 0,007 0,008 0,003 0,008 0,025 0,006 0,002 0,01 0,01

Zinc mg/kg 0,02 0,01 <0.01 <0.01 <0.01 <0.01 0,01 0,01 0,02 0,01 0,01 0,01

Cadmium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Chromium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Copper mg/kg <0.01 <0.01 0,03 <0.01 <0.01 <0.01 0,02 <0.01 <0.01 <0.01 <0.01 0,03

Manganese mg/kg 0,76 0,79 0,38 88,37 28,90 82,70 29,92 0,83 0,92 0,79 0,8 33,1

Faecal Coliform Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 9000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 15000

Total Colifom Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000



136

Table 9. Water quality parameters Zone E (Sg. Maong) 1999. Mean of four sampling sites. Wet season: Nov-Feb. Dry season: Mar-

Oct.




pH Value 6,9 7,2 6,9 6,7 7,0 7,1 7,1 7,1 7,0 7,0 6,5 6,9 7,0

Dissolved Oxygen mg/kg 0,6 0,6 0,4 0,7 0,5 0,1 0,8 1,5 2,3 4,8 2,5 1,3 1,4

Biochemical Oxygen Demand mg/kg 13,1 13,6 11,1 7,9 11,0 36,5 11,3 8,5 6,6 2,5 2,0 9,6 11,9

Chemical Oxygen Demand mg/kg 32,5 40,6 28,4 24,1 37,9 49,3 43,5 62,5 28,0 26,1 32,4 35,2 37,5

Total Suspended Solids mg/kg 21,3 17,6 17,6 17,5 12,3 19,8 7,6 17,3 14,0 34,3 7,8 15,6 17,5

Ammoniacal Nitrogen mg/kg 0,98 4,67 2,06 1,14 3,19 7,74 5,85 9,83 6,20 0,45 0,92 2,2 4,6

Nitrate mg/kg <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Mercury mg/kg - - - - 0,0006 <0.0002 <0.0002 0,0005 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Lead mg/kg <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

Arsenic mg/kg 0,005 0,003 0,004 0,003 0,004 0,008 0,003 0,014 0,004 0,005 0,003 0,004 0,006

Zinc mg/kg 0,24 0,13 0,02 <0.01 <0.01 <0.01 <0.01 <0.01 0,01 0,03 0,03 0,13 0,02

Cadmium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Chromium mg/kg <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Copper mg/kg <0.01 <0.01 0,03 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Iron mg/kg 2,93 2,1 1,82 0,82 1,38 1,44 0,64 0,91 2,57 1,64 1,01 2,01 1,34

Manganese mg/kg 0,17 0,12 0,10 0,05 0,07 0,05 0,05 0,12 0,13 0,13 0,04 0,11 0,09

Faecal Coliform Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 9000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 15000

Total Colifom Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000



137

Table 10. Water quality parameters Zone E (Sg. Maong) 2000. Mean of four sampling sites. Wet season: Nov-Feb. Dry season:

Mar-Oct.



No. of Samples Analysed 4 4 4 4 4 4 4 4 4 4 4 4 4

pH Value - 6,6 7,0 6,9 7,1 7,0 6,9 6,7 6,6 6,9

Dissolved Oxygen - 2,6 0,3 2,7 0,5 0,3 0,7 0,4 2,6 0,8

Biochemical Oxygen Demand - 3,6 6,8 1,6 9,4 4,0 5,9 8,5 3,6 6,0

Chemical Oxygen Demand - 27,0 28,4 21,6 40,6 37,2 37,1 28,9 27,0 32,3

Total Suspended Solids - 12,0 23,0 28,3 25,0 31,5 33,0 26,0 12,0 27,8

Ammoniacal Nitrogen - 1,99 8,05 0,05 6,37 3,57 3,75 6,38 2,0 4,7

Nitrate - <0.5 <0.5 0,90 <0.5 1,40 <0.5 <0.5 0,90 0,90 <0.5 <0.5

Mercury <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Lead <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

Arsenic 0,004 0,003 0,013 0,003 0,002 0,003 0,003 0,002 0,003 0,003 <0.001 <0.001

Zinc 0,10 <0.01 <0.01 <0.01 0,01 <0.01 0,04 0,33 0,03 0,06 0,10 0,09

Cadmium <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Chromium <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001

Copper <0.01 <0.01 0,03 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Manganese 0,80 0,99 0,92 1,22 0,70 1,11 21,20 3,40 3,25 0,67 0,90 4,06

Faecal Coliform Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000

Total Colifom Count (MPN/100mL) > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000 > 16000

River Quality Baseline Study. Vol. 1 138


APPENDIX 2

AN OVERVIEW OF THE STATE ADMINISTRATION

TYT YANG DI-PERTUA NEGERI

LEGISLATIVE EXECUTIVE JUDICIARY

SPEAKER CHIEF MINISTER BORNEO HIGH COURT

DEWAN UNDANGAN CABINET (MMKN) SESSION COURT

CHIEF MINISTER'S DEPARTMENT MAGISTRATE COURT

ADAT COURT

MINISTRIES

1 Ministry of Planning & Resource Management

2 Ministry of Finance and Public Utilities

3 Ministry of Rural and Land Development

4 Ministry of Environment and Public Health

5 Ministry of Tourism

6 Ministry of Housing

7 Ministry of Industrial Development

8 Ministry of Agriculture and Food Industry

9 Ministry of Social Development & Urbanisation

10 Ministry of Infrastructure Development

& Communications

1. Chief Minister’s Department

State Planning Unit (SPU)

Kuching City North Hall (DBKU)

2. Ministry of Planning and Resources Management

Land and Survey Department

Forest Department

3. Ministry of Finance and Public Utilities

Water Authority

Water Boards (Water Supply)

4. Ministry of Rural and Land Development

Drainage and Irrigation Department (DID)

5. Ministry of Environment and Public Health (MOEPH)

Kuching City South Council (MBKS)

Padawan Municipal Council (MPP)

District Councils (Bau, Samarahan, Serian)

State Health Department


6. Ministry of Industrial Development



7. Ministry of Agriculture and Food Industry

Department of Agriculture

8. Ministry of Infrastructure Development and Communication

Public Works Department (JKR) – the Water Resources Division

Kuching Port Authority

Sarawak Rivers Board (SBR)

9. Minsitry of Tourism

10. Minsityr of Housing

11. Ministry of Social Development & Urbanisation

12. Other Relevant Committees and Councils

State Planning Authority

Water Resources Council



APPENDIX 3

A SUMMARY OF RELEVANT ACTIVITIES AND MANDATES

Name of Agency Relevant activities Relevant regulation

State Planning Unit Overall economic plan-

ning. Infrastructure pro-

jects including waste and

wastewater projects

State Planning Author-

ity

Approval of develop-

ment projects

Water Resources

Council

Policy and programmes

for conservation, man-

agement and use of water

resources

WO 4

Water Authority Water supply.

Identification of water

catchments, control of

contamination and pollu-

tion of water or sources

of water supply, licenses

for water abstraction

WO 8 and 17

Land and Survey De-

partment

Agency for landuse (e.g.

sand extraction from riv-

ers and utilization of river

banks), land classifica-

tion and development –

Secretariat to the SPA

Drainage and Irriga-

tion Department

Irrigation and drainage

works, river engineering,

flood mitigation, hydrol-

ogy, data collection,

No regulation

State Health Depart-

ment

License of businesses,

discharge from hospitals

and certain food outlets

PHO

21, 25, 33, and 38

Local Authorities

Approval of building

plans

Construction and mainte-

nance of public drains

Sewage treatment

Collection and disposal

of waste

License of businesses

Operation of markets

Nuisances

LAO

104, 105, 112, 132,

134, 136, 138

Entire LAC in par-

ticular

9-17, 18- 20, 41, 44-

50

Natural Resources and

Environment Board

Broad powers within pol-

icy making, coordination

and monitoring. Pollution

control powers e.g. EIA,

NREO

5, 10, 11, 18 and 30

and subsidiary rules

under these provi-



environmental manage-

ment systems and issu-

ance of rules and orders.

sions

Ministry of Industrial

Development

License for industrial ac-

tivities (in Industrial Es-

tates)

Only licenses for

operation

Department of Agri-

culture

Soil conservation

Drainage and irrigation

Crop water requirement

Pollution from non-point

sources

License of aquaculture

SIFR 6

State Veterinary

Health Department

License of businesses

(lifestock rearing, meat

processing)

VPHO

7, 22, 29, 42, 44, 69,

102

Public Works Depart-

ment

The Water Resources

Division

Responsible for infra-

structure development for

water supply and sewer-

age - Secretariat to The

Water Authority and the

Water Resources Council

advising the Minister on

water resources issues

and identification of wa-

ter catchment areas

Sarawak Rivers Board Regulate river traffic –

power to prohibit dis-

charge to gazetted rivers

from public and private

sources and regulate ac-

tivities in the rivers and

on the banks of gazetted

rivers

SRO

4, 9, 12, 13, 16,17,

20, 33, 38

SRCR

3, 6, 8, 10, 12, 15,

17, 12, 22

Kuching Port Author-

ity

Provide port facility

Department of Envi-

ronment

(Federal Agency)

Broad powers within na-

tional policy making,

monitoring and co-

ordination. Pollution con-

trol powers e.g. EIA, li-

censing of industry, stan-

dard setting

EQA

3, 11, 12, 18, 21 and

32

EQA Sewage Regu-

lation

4, 6, 8, 11