environment of sg. sarawak: relationships between city and river
TRANSCRIPT
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
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
Report no. SUD-02-25
Issue no. 02
Date of issue 4 September 2001
Prepared ERP, HBJ, Chemsain, Daya Rancang
Checked ILA
Approved ILA
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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
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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.
Surface water quality
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),
Heavy metals (Hg, Pb,
As, Zn, Cd, Cr, Cu, Ni, )
PAH, Total petroleum
hydrocarbons
Loss on ignition
Total N
Total P
Fe, Ni
Pollutants in
aquatic organ-
isms
Heavy metals (Hg, Pb,
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).
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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.
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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
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Table 2.1 (continued)
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;
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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.
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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).
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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:
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- 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.
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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.
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Figure 4.1. Sg. Sarawak and its main tributaries.
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Figure 4.2. Tributaries of Sg. Sarawak in the Kuching City.
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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.
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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.
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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).
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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
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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
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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.
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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).
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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
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Table 4.2 (continued)
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 south- east of the study area near Sg.
Kuap, the Sama Jaya Free Industrial Zone. There is also a smaller industry zone
at Demak Laut.
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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.
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Figure 4.6. Landuse of catchment areas in Kuching discharging to Sg. Sarawak
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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
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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.
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Figure 4.7. Location of pig farms in the catchment areas of the Sg. Sarawak
system.
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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.
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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-
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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.
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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).
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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).
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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-
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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.
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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.
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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).
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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.
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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
Quality Data for Southern Region
January – December 1999
January – December 2000
(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
Quality Data for Southern Region
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
Quality Data for Southern Region
January – November 1999
January – December 2000
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
Quality Data for Southern Region
January – September 2000
Zone I
Sg. Tabuan (St 1-St 6)
k) UNIMAS study. Sampling in September and December
1999
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Figure 5.2. Water Quality Monitoring Sites in the City of Kuching.
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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.
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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
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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
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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;
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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.
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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.
Table 5.7 Mean concentrations of selected water quality parameters in Zone
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
No samples 8 16 8 12
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
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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).
Table 5.8 Mean concentrations of selected water quality parameters in Zone
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
No samples 8 18 4 16
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).
Table 5.9 Mean concentrations of selected water quality parameters in Zone
D (main Sg. Sarawak from Satok Bridge to Downstream of Barrage). Wet
season: Nov-Feb. Dry season: Mar-Oct.
Parameter Wet Season
1999
Dry Season
1999
Wet Season
2000
Dry Season
2000
INWQS
class IIB
No samples 16 50 12 36
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
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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).
Table 5.10 Mean concentrations of selected water quality parameters in Zone
E (Sg. Maong). Wet season: Nov-Feb. Dry season: Mar-Oct.
Parameter Wet Season
1999
Dry Season
1999
Wet Season
2000
Dry Season
2000
INWQS
class IIB
No samples 12 32 4 24
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
Table 5.11 Mean concentrations of selected water quality parameters in Zone
F (Sg. Bintangor). Wet season: Nov-Feb. Dry season: Mar-Oct.
Parameter Wet Season
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
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Table 5.12 Mean concentrations of selected water quality parameters in Zone
G (Sg. Padungan). Wet season: Nov-Feb. Dry season: Mar-Oct
Parameter Wet Season
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
Table 5.13 Mean concentrations of selected water quality parameters in Zone
H (Sg.Sekama). Wet season: Nov-Feb. Dry season: Mar-Oct
Parameter Wet Season
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
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Table 5.14 Mean concentrations of selected water quality parameters in Zone
I (Sg. Tabuan. Wet season: Nov-Feb. Dry season: Mar-Oct
Parameter Wet Season
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).
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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.
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Fig 5.4. Sampling locations for sediments in Sg. Sarawak in November 2000
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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 %
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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
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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
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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
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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
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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).
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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)
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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
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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
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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
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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.
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Figure 5.19. Sediment sampling sites.
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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.
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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
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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
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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
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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
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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.
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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, %
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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
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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
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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.
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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 black- water which have been cho-
sen as indicators for pollution from households are ammoniacal nitrogen, phos-
phorous, BOD, COD, faecal coliforms, total coliforms and TSS.
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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).
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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.
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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.
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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
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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.
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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.
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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.
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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
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6.3.3 Treatment Facilities and Draining Systems
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.
6.3.4 Control and Enforcement Measures
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.
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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.
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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
Siol Kandis 2 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.
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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-
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.
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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
Bintangor 1 - - - - -
Bintangor 2 - - - - -
Bintangor 3 - - - - -
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
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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
6.4.3 Treatment Facilities and Draining Systems
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.
6.4.4 Control and Enforcement Measures
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;
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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).
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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-1 0 0 0 0 0
Bintangor-2 0 0 0 0 0
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
Siol Kandis 1 0 0 0 0 0
Siol Kandis 2 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.
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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.
6.5.2 Treatment Facilities and Draining Systems
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.
6.5.3 Control and Enforcement Measures
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
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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
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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.
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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)
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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.
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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-
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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.
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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.
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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.
Table 7.1 Estimated loads of pollutants to Sg. Sarawak and tributaries from
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
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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
three types of sources
in the sub-catchment
area
Industries
% of
total load from the
three types of sources
in the sub-catchment
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
Siol Kandis 2 100 0 0
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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
three types of sources
in the sub-catchment
area
Food outlets
% of
total load from the
three types of sources
in the sub-catchment
area
Industries
% of
total load from the
three types of sources
in the sub-catchment
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
Siol Kandis 1 100 0 0
Siol Kandis 2 100 0 0
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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).
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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.
Table 7.4 Estimated loads of pollutants to Sg. Sarawak and tributaries from
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
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Table 7.5 Estimated loads of pollutants to Sg. Sarawak and tributaries from
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
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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.
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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
Surface water quality
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-
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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).
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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
Preliminary indicators proposed not to be included in the EMS
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.
Indicators proposed to be included in the EMS
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.
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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.
Indicators proposed to be included in the EMS
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.
Preliminary indicators proposed not to be included in the EMS
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.
Indicators proposed to be included in the EMS
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).
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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.
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APPENDIX 1
WATER QUALITY DATA
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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
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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
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 6,7 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
Total Colifom Count (MPN/100mL) 6333 13667 1367 11667 16000 16000 3000 8000 9504 9339
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Table 3. Water quality parameters Zone B (Sg. Sarawak Kiri) 1999. Mean of two sampling sites. Wet season: Nov-Feb. Dry season:
Mar-Oct.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
No. of Samples Analysed 2 2 2 2 2 2 2 2 2 2 2 2 2 2
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
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Table 4. Water quality parameters Zone B (Sg. Sarawak Kiri) 2000. Mean of two sampling sites. Wet season: Nov-Feb. Dry season:
Mar-Oct.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
No. of Samples Analysed 2 2 2 2 2 2 2 2 2 2 2 2 2 2
pH Value 6,9 6,7 7,2 7,1 7,0 6,9 7,0 7,0 6,8 7,0
Dissolved Oxygen mg/kg 7,6 3,8 6,9 7,0 7,1 6,8 2,6 2,2 5,7 5,4
Biochemical Oxygen Demand mg/kg 0,3 0,5 0,4 1,2 0,5 0,7 0,8 1,2 0,4 0,8
Chemical Oxygen Demand mg/kg 7,2 22,8 5,0 12,2 8,2 15,4 3,9 18,8 15,0 10,6
Total Suspended Solids mg/kg 27,0 256,5 65,0 27,0 130,5 35,7 7,7 88,5 141,8 59,1
Ammoniacal Nitrogen mg/kg 0,05 0,05 0,05 0,10 0,05 0,12 0,10 0,12 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
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
Total Colifom Count (MPN/100mL) 6000 16000 8800 10500 16000 12500 8120 16000 11740 11987
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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.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
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
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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.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
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
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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.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
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
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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.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
No. of Samples Analysed 6 6 6 6 6 6 6 6 6 6 6 6 6 6
pH Value 6,5 6,4 7,0 7,0 6,9 7,0 7,0 6,7 6,5 6,9
Dissolved Oxygen mg/kg 7,8 6,0 5,2 4,6 5,0 2,2 2,8 3,0 6,9 3,8
Biochemical Oxygen Demand mg/kg 0,5 0,3 1,0 0,5 0,5 0,4 0,7 3,9 0,4 1,2
Chemical Oxygen Demand mg/kg 9,4 4,0 6,2 13,7 7,8 14,4 22,5 25,0 6,7 14,9
Total Suspended Solids mg/kg 49,8 37,7 18,0 51,0 24,3 248,0 50,2 49,5 43,7 73,5
Ammoniacal Nitrogen mg/kg 0,10 0,10 0,21 0,15 0,05 0,05 0,14 1,21 0,1 0,3
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
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Table 9. Water quality parameters Zone E (Sg. Maong) 1999. Mean of four sampling sites. Wet season: Nov-Feb. Dry season: Mar-
Oct.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
No. of Samples Analysed 4 4 4 4 4 4 4 4 4 4 4 4 4 4
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
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Table 10. Water quality parameters Zone E (Sg. Maong) 2000. Mean of four sampling sites. Wet season: Nov-Feb. Dry season:
Mar-Oct.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Average Average
Parameter Wet Wet Dry Dry Dry Dry Dry Dry Dry Dry Wet Wet Wet Dry
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
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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
Natural Resources and Environment Board
6. Ministry of Industrial Development
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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
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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-
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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