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Drinking Water Quality

Annual Report 2012/13

2 Title 2 Drinking Water Quality Annual Report 2012/13

Contents

Common terms .............................................................. 2

Summary ....................................................................... 5

Our commitment to you ................................................. 6

Introduction .................................................................. 7

Where does your water come from? .............................. 8

Perth Metropolitan Region.................................................. 8

South West Region ......................................................... 11

Goldfields and Agricultural Region..................................... 12

Great Southern Region .................................................... 13

North West Region .......................................................... 14

Mid West Region............................................................. 15

What drinking water guidelines must we meet? .......... 16

Case Studies ................................................................ 22

Case Study 1: Introduction to the Framework for

Management of Drinking Water Quality ............................. 22

Case Study 2: Source Protection Signage and

Barrier Project ............................................................... 24

Case Study 3: Feed Forward Control ................................. 25

How is your water treated? ......................................... 27

Understanding water quality test results .................... 31

Performance at a glance .............................................. 36

Customer expectations ................................................ 39

Improving your water quality ..................................... 41

Appendix A – List of parameters within sampling

groups ......................................................................... 43

Appendix B – List of all sampling parameters ............. 46

Appendix C – Summary of test results ......................... 48

Appendix D - Supporting information for water source

location maps .............................................................. 49

ISSN 2202-879X October 2013


About this report

The Water Corporation’s 2012/13 Drinking Water Quality

Annual Report is a review of our performance for the financial

year ending 30 June 2013.

This report is specifically designed to provide our customers

and the Western Australian public with information on the

quality of their drinking water.

Publication of this report allows us to meet the requirements of

the Australian Drinking Water Guidelines, our Operating

Licence requirements with the Economic Regulation Authority,

the requirements of the Memorandum of Understanding with

the Department of Health and the reporting requirements of

the National Water Commission.

http://www.erawa.com.au/cproot/4438/2/20110125%20D58407%20Water%20Corporation%20Water%20Operating%20Licence%2032.pdf


http://www.watercorporation.com.au/-/media/Files/About%20us/Our%20performance/Drinking%20water%20quality/Drinking-water-MoU.pdf


ADWG Australian Drinking Water Guidelines

CAWS Country Areas Water Supply

DOC Dissolved organic carbon

DPaW Department of Parks and Wildlife

DoW Department of Water

EDR Electrodialysis Reversal

GAWS Goldfields and Agricultural Water Supply

GSTWS Great Southern Towns Water Supply

IWSS Perth Integrated Water Supply Scheme

LGSTWS Lower Great Southern Towns Water Supply

LTE Long Term Evaluation

MIEX Magnetic Ion Exchange

ML One megalitre (equals one million litres)

MWSSD Metropolitan Water Supply, Sewerage and Drainage

NHMRC National Health and Medical Research Council

PDWSA Public Drinking Water Source Area

RO Reverse Osmosis

UV Ultra-violet Disinfection

WSAA Water Services Association of Australia

WSP Water Safety Plan

Common terms


Supplying safe drinking water is our highest priority. In

2012/13, we achieved outstanding compliance results for

health-related characteristics and met all our health targets for

drinking water quality set by the Department of Health.

Health related performance:

100 per cent compliance with microbiological guidelines

100 per cent compliance with health related chemical

guidelines

Non-health (aesthetic) related performance:

64 per cent compliance with aesthetic guidelines

We strive to meet guidelines for aesthetic characteristics,

however, this is very difficult to achieve in a state as vast as

Western Australia with a wide variety of water sources. This is

especially the case in some of our small country water

schemes where there can be few sources of water drinking

available and where installation of treatment can be very

costly.

Although we meet all our obligations under the Operating

Licence, we recognise there are always opportunities for

improvement.

This is our 11th Drinking Water Quality Annual Report and we

trust this report provides our customers with the information

they require about their drinking water quality. We welcome

any comments and feedback by contacting us on 13 13 75 or

[email protected]

Summary

Two Peoples Bay, Great Southern Region




We are committed to providing our customers with safe, high-

quality supply drinking water that consistently meets the

Australian Drinking Water Guidelines (ADWG), customers and

other regulatory requirements.

To achieve this, we will in partnership with stakeholders and

relevant agencies:

Take a ‘catchment to tap’ approach to managing and

protecting water quality from the source through to our

customers.

Strongly advocate source protection and primacy of

drinking water quality over other land uses.

Use a risk-based approach to identify and manage

potential threats to water quality.

Comply with the health-related criteria of the ADWG

and work to progressively improve compliance with

aesthetic criteria.

Use appropriate contingency planning and incident

response capability.

Incorporate the needs and expectations of our

customers, stakeholders, regulators and employees.

Routinely monitor the quality of drinking water and use

effective reporting mechanisms to provide relevant and

timely information, and promote confidence in the

water supply and its management.

Participate in research and development activities to

ensure continued understanding of drinking water

quality issues and performance.

Contribute to setting industry regulations and

guidelines, and other standards relevant to public

health and the water cycle.

Continually improve our practices by assessing

performance against corporate commitments and

stakeholder expectations.

We will implement and maintain a management system

consistent with the ADWG to protect our drinking water

quality. All managers and employees involved in the supply of

drinking water are responsible for understanding,

implementing, maintaining and continuously improving the

drinking water quality management system.

Our commitment to you


We provide drinking water to Perth and over 220 small

communities scattered throughout Western Australia.

This year we delivered 357.3 billion litres of drinking water

from 126 dams and weirs, 94 licensed borefields and the Perth

and Southern Seawater Desalination plants, to over a million

properties through 33,823 kilometres of water mains.

To put that into perspective, that means that last year we

supplied enough water to fill Pattersons Stadium to its

goalposts nearly 358 times.

Under our Operating Licence we comply with a Memorandum

of Understanding with the Department of Health. We act in

accordance with the microbiological, health chemical and

radiological parameters as specified by the National Health and

Medical Research Council (NHMRC) in the ADWG.

Our health performance (chemical, microbiological, and

radiological) has this year again resulted in 100 per cent of

metropolitan and country localities meeting the high standards

set by the Department of Health.

An extensive drinking water quality monitoring program

confirms the safety of the water we provide to our customers.

Bacterial and chemical analyses are carried out by

independent laboratories, approved by the Department of

Health.

Victoria Dam

Introduction





This section provides an overview of the water supplies in each

of our six regions.

Perth Metropolitan Region

Our largest scheme, the Integrated Water Supply Scheme

(IWSS) delivers 285 billion litres of water each year to more

than 1.9 million customers in Perth, the Goldfields and

Agricultural Region, and parts of the South West.

Surface water comes from eight dams in the Darling Range:

South and North Dandalup, Serpentine, Wungong, Churchman

Brook, Canning, Victoria and Mundaring Weir. Water is also

supplied from Stirling and Samson Dams in our South West

Region.

Groundwater is drawn from the Yarragadee, Leederville,

Mirrabooka and other shallow aquifers. Most of the 180 bores

are located in Perth's northern suburbs. Groundwater is

treated at six groundwater treatment plants. There are also 12

independent artesian bores which pump water directly into

service reservoirs.

In 2012/13, drinking water production for the IWSS was

delivered on target and within overall water allocation and

license parameters. Total groundwater abstracted was 140.2

billion litres, against an allocation of 140.3 billion litres. Water

supplied consisted of 33 per cent surface water, 40 per cent

Where does your water come from?

9 Drinking Water Quality Annual Report 2012/13

Diagrammatic representation of the main Drinking Water sources for Perth (from Water Corporation's How water gets to my tap Lesson Plan

groundwater and 27 per cent from desalination. The

proportion of desalinated water will increase to above 40 per

cent when the second stage of the Southern Seawater

Desalination Plant is fully commissioned in late 2013.

To optimise the amount of water available for the IWSS,

customers may receive a mix of groundwater, surface water

and desalinated seawater. The percentage of each depends on

seasonal factors. Yanchep and Two Rocks are special cases in

the Perth region, as they have their own independent

groundwater supplies. Eventually these suburbs will join the

IWSS.

The Perth Seawater

Desalination Plant in

Kwinana exceeded its

rated annual production

capacity of 45 billion litres

by delivering 48.3 billion

litres into the IWSS. This

is the fourth year in a row

this climate independent

source has achieved above

average production. This is

the result of ongoing

improvements and

efficiency measures at the

plant. The desalinated water enters the IWSS through

Thomsons Reservoir where it is blended with Jandakot

groundwater and surface water from dams. A portion can be

stored in Canning Dam and Wungong Dam during periods of

low demand in the winter.

The Southern Seawater Desalination Plant in Binningup, which

last year won Desalination Plant of the Year at the Global

Water Awards, continued to increase production, delivering

47.4 billion litres for the 2012/13 year. In response to our

drying climate the decision was made to double the capacity of

the plant to 100 billion litres of water per year.

Southern Seawater Desalination, Binningup


Together, these two climate independent water sources will be

able to provide above 40 per cent of drinking water to the

IWSS.

The Mundaring Water Treatment Plant and pump station is

being commissioned with first water due from the plant due

into the system at the end of 2013. Launched in 2011, this

work is being funded, built and operated by Helena Water

consortium (compromising ACCIONA Agua, TRILITY and Lloyds

Bank Corporate Markets), in Western Australia’s first Public

Private Partnership (PPP) in the water industry. Helena Water

will provide us with drinking water to meet the needs of the

Goldfields and Agricultural Water Supply (GAWS) for up to 35

years, when the plant will be handed over to us in full

operating condition. We are combining private sector

commerciality with our technical expertise, to drive efficient

operations and lowest possible cost. The Aroona Alliance

manages our metropolitan water production and the Perth

Region Alliance has responsibility for the operations and

maintenance of all our metropolitan services.

Mundaring Weir Wall


South West Region

Towns in the South West Region are supplied with water from

a number of surface and groundwater sources that are largely

independent. Harvey, Waroona, Hamel, Binningup, Myalup and

Yarloop are supplied from the IWSS.

Bridgetown, Nannup, Hester, Boyup Brook, Greenbushes,

Balingup and Manjimup are now connected to the Warren

Blackwood Regional Water Scheme and can be supplied from a

Yarragadee Bore near Nannup via the Millstream and

Manjimup Dams. In December 2012, we completed an

upgrade to Millstream Dam near Bridgetown, which is central

storage for the Warren-Blackwood Regional Water Supply

Scheme. The upgrade doubled the dam’s capacity to 1.06

billion litres.

Australind, Eaton, Pelican Point, Millbridge, Treendale,

Kingston, Brunswick Junction, Roelands and Burekup are

supplied with water sources from Leederville and Yarragadee

bores, via water treatment plants in Australind, Eaton and

Picton. Harris Dam supplies Collie, Allanson and Darkan as well

around 35 towns in the Great Southern Region.

The Margaret River was used for the last time in 2012/13 to

ensure the Ten Mile Brook Dam had adequate storage for the

summer 2012/13. The pump back is no longer required due to


commissioning of the Lilly Road Water Treatment Plant and

the Margaret River Production Bore 1/10.

Some of our customers in Australind experienced discoloured

water in 2012/13. Discoloured water is caused by an increase

in flow or change in direction of water, which can stir up

harmless sediment that has settled in pipes over a long period

of time. We conducted an extensive pipe and tank cleaning

program to alleviate the issue.

We review similar schemes across the state and initiate

cleaning programs as required to reduce the chance of

discoloured water for our customers.

Goldfields and Agricultural Region

The Goldfields and Agricultural Water Supply (GAWS) draws

most of its water from Mundaring Weir near Perth and supplies

the majority of towns in the Goldfields and Agricultural Region.

The remaining towns, Laverton, Leonora, Menzies and Wiluna

are supplied from local groundwater sources.

Water supplied to most of the towns is chloraminated with the

remainder being chlorinated (refer to “Disinfection” on page

27). In Kalgoorlie-Boulder, a recently commissioned separate

inlet system to Mt Percy and Mt Charlotte tanks enables all of

the supply to be delivered via tanks, resulting in a more


consistent amount of chlorine in the water being supplied to all

customers.

Work is due to start on the construction of the Cunderdin

storage tanks which will replace the old unroofed Cunderdin

Reservoir.

Great Southern Region

In the Great Southern Region, we have two main water supply

schemes - the Great Southern Towns Water Supply Scheme

(GSTWS) and the Lower Great Southern Towns Water Supply

Scheme (LGSTWS). Harris Dam near Collie is the main source

for the GSTWS and the South Coast borefields are the main

source for the LGSTWS, although a number of towns have

local sources which can contribute to the supply if required.

The area known as the South Coastal District recently joined

our Great Southern Region from the Goldfields and Agricultural

Region. This includes the Condingup, Gibson, Esperance and

Hopetoun groundwater schemes and Grass Patch, Salmon

Gums, Munglinup and Ravensthorpe surface water schemes.

Ravensthorpe has both ground and surface water components

to the scheme.

As part of the long term plan to reduce draw from less suitable

bores, we drilled two additional production bores in Esperance


this year. In addition, a number of monitoring bores were

drilled in Albany to improve monitoring of groundwater.

We began a source protection initiative in the region last year

and have completed a number of projects. We upgraded

fences and gates at Two People’s Bay, Jerramungup, Narrogin

(Bottle Creek) and Ongerup. We will continue these upgrades

to protect our water sources.

North West Region

The West Pilbara Water Supply Scheme supplies customers in

Karratha, Dampier and the neighbouring towns of Roebourne,

Wickham, Point Samson, Cape Lambert and the Burrup

Peninsula. The scheme currently has two sources: Harding

Dam and Millstream borefield. Rio Tinto Iron Ore is developing

a groundwater source in the Bungaroo Valley, which will free

up water for the scheme.

The East Pilbara Water Supply Scheme supplies customers in

Port Hedland, South Hedland, Wedgefield Industrial Area and

the local port operations. The scheme is supplied with

groundwater from the Yule and De Grey River borefields.

In the Kimberley area, the town of Kununurra is supplied by a

local groundwater source. The remaining towns in the North

West Region are supplied by local independent groundwater

sources, with the exception of Wyndham which is supplied by

Moochalabra Dam.

Additional water sources are coming online with the expansion

of the Cane River borefield in Onslow due to be complete by

the end of 2013. The Yule and De Grey River borefield


expansion to supply the Hedland scheme will be complete by

2014. Discussions are continuing with Chevron, who are

working with the Water Corporation on new water sources for

Onslow.

Projects driven by sustained growth in the Kimberley Region

are underway to upgrade water supply schemes and

infrastructure. In Broome, work has been completed on a

second storage tank increasing storage capacity by 40 per

cent and a pH correction dosing plant has been installed.

Mid West Region

The Mid West Region, which supplies drinking water to 52

localities, uses independent groundwater sources. In a region

facing challenges from scarce and brackish (highly saline)

water supplies, we are working to ensure reliable access to a

quality drinking water supply.

Over the past 10 months, extensive work has been completed

in the coastal towns (Horrocks, Yerecoin, Seabird, Woodridge,

Moora, Dandaragan and Bindoon) on refurbishing filters within

the water treatment plants in order to improve aesthetic water

quality through the removal of dissolved metals, specifically

iron and manganese.

We also appointed the region’s first Catchment Ranger in

September 2012, a role which reinforces drinking water quality

management processes and water source protection across

the vast Mid West Region.


The National Health and Medical Research Council (NHMRC)

define the requirements for safe drinking water in Australia

through the ADWG. These guidelines include a Framework for

best practice management of drinking water supplies designed

to integrate all facets of the drinking water quality

management and assurance system. We, along with the

Department of Health, contribute to the rolling revision of the

ADWG.

We have a Memorandum of Understanding with the

Department of Health which requires our compliance with the

microbiological, health chemical and radiological parameters

as specified in the ADWG. This forms part of our Operating

Licence as issued by the Economic Regulation Authority. We,

along with the Department of Health, recognise that the

practices and processes used to establish and maintain high

levels of drinking water quality need to be open and

transparent to the community.

A key enhancement of the 2011 ADWG has been the

strengthening of operational monitoring. This means moving

away from just meeting drinking water quality guideline

values, towards a total system management, understanding

risks and continuous improvement. In addition to this, there is

now the requirement of undertaking a Long Term Evaluation

(LTE) when there is a microbiological detection, chemical or

radiological result above the ADWG health guideline. LTE is

used to evaluate whether the system is sufficiently robust to

deliver safe drinking water under all foreseeable conditions.

For aesthetic parameters, the Memorandum of Understanding

states that we should comply as far as practical with the

ADWG for non-health related characteristics. It is accepted

that the achievement of this may take a number of years

bearing in mind the high levels of public expenditure which

would be required to achieve full compliance. For more

information on our program of water quality improvements

please refer to “Improving Your Water Quality” on page 41.

Drinking Water Quality Team, Perth Seawater Desalination Plant

What drinking water guidelines

must we meet?






Reservoir Protection sign, Mundaring Weir

Multiple barrier approach

Preventing contamination and minimising potential hazards is

an essential part of providing our customers with safe drinking

water. The ADWG emphasise the importance of using multiple

barriers to ensure the safety of drinking water. Barriers

include:

Protected catchments and groundwater recharge areas

Large reservoirs with long water detention (storage)

times

Water treatment (refer to “How is your water treated?”

on page 26)

Disinfection of water

Maintaining chlorine residuals through the distribution

system

Ensuring tanks and bores are sealed to prevent

contamination.

We have been working over an extended period of time to

implement the multiple barrier approach throughout our

drinking water systems.

Water Safety Plans

The development of Water Safety Plans is a process we use to

meet the Department of Health requirement to implement the

Framework for Management of Drinking Water Quality. Water

Safety Plans use a systematic risk management approach from

catchment to tap assessing the risks to each water supply,

ensuring that appropriate preventative measures are in place,

and identifying the operational controls necessary to

consistently ensure the safety of drinking water. Last year’s

report celebrated the completion of all Water Safety Plans

across the state and this year an in-depth review of 41

schemes in the country and 13 in the metropolitan region have

been completed. All Water Safety Plans are continually

reviewed every four years, to re-evaluate the scheme and

update any site or treatment details.

Source Protection

Protection and management of drinking water catchments is

the most important barrier to drinking water contamination as

it ensures the highest quality raw water is used for drinking

water. The ADWG recognises that “prevention of

contamination provides

greater surety than removal

of contaminants by

treatment, so the most

effective barrier is

protection of source water

to the maximum degree

practical”.

Western Australia’s water

regulator, Department of

Water (DoW), has statutory

responsibility for water


Canning Reservoir - Erosion control

matting to reduce gullying

source protection in Western Australia. Groundwater and

surface water Public Drinking Water Source Areas (PDWSAs)

are proclaimed, gazetted and protected under the Metropolitan

Water Supply, Sewerage and Drainage (MWSSD) Act 1909 or

the Country Areas Water Supply (CAWS) Act 1947 and their

associated by-laws. These by-laws outline activities that

cannot occur in drinking water catchments because they have

the potential to contaminate drinking water supplies.

As of January 2013 the Water Corporation was delegated

catchment management powers from the DoW for all drinking

water sources proclaimed under the CAWS Act 1947. Until this

time, delegated powers only applied to specific delegated

sources in country areas and all metro sources proclaimed

under MWSSD. Among other things, this gives us the power to

prosecute for by-law infringements. You can obtain more

information on Proclaimed public drinking water source areas

through the DoW website www.water.wa.gov.au.

As a delegated source protection authority, we work closely

with the DoW to develop State-wide source protection policies,

guidelines and standards. We have an Operational Agreement

with the DoW which delegates on-the-ground management of

many catchments to us. We have documented procedures and

manuals to guide catchment operations and ensure compliance

with our delegated responsibilities.

Catchment Management

Strategies have been

developed for every

drinking water source to

identify, assess, manage

and minimise adverse

impacts on water quality

which may result from

land uses and other

activities within the

catchment. Each

Catchment Management Strategy includes a risk assessment

of the land uses and catchment activities. Potential risks to

drinking water quality are identified and the assessment is

used to determine the many management options, water

sampling and catchment surveillance programs.

Regular catchment surveillance ensures we are aware of

activities and changes in our catchments. It also provides an

opportunity to educate members of the public that are

performing activities that could contaminate drinking water.

Other responsibilities include feral animal control, weed

control, fencing and sign inspections, rubbish removal, event-

based water sampling, assisting with research, recreation

event inspections, mining and forestry operation inspections

and pollution response.

http://www.water.wa.gov.au/PublicationStore/first/104030.pdf


These actions protect the natural purification processes in our

dams and aquifers and reduce the risk of contamination of our

raw water sources. In this way, our source protection program

also works towards corporate sustainability goals, minimising

the need for water treatment plants at our sources.

We carry out extensive catchment protection to minimise the

possibility of water sources being contaminated with

pathogens, particularly those carried by humans and domestic

animals such as cows and dogs. These microorganisms can be

carried and transferred into our drinking water sources by

direct body contact with the water, run-off over land when it

rains or dust blown in on the wind. Activities in or close to the

reservoir and feeder streams pose the greatest risk.

To provide extra protection around our catchments where it is

needed the most, DoW legislation includes provisions for

special exclusion zones, detailed below:

• 2 kilometre exclusion areas around the high water

mark of reservoirs known as ‘Reservoir Protection

Zones’

• ‘Wellhead Protection Zones’ of either 300 metres or 500

metres around drinking water production bores.

In the outer catchment areas, the risk of pathogen

contamination is minimised by restricting access to only

passive recreational activities such as hiking and mountain-

biking on designated trails.


Water Corporation staff collecting a sample

Monitoring

In accordance with the

ADWG, we run an extensive

drinking water quality

monitoring program to

confirm the safety of the

water we provide to our

customers. We take more

than 65,000 water samples

each year from water

sources, treatment plants

and pipe networks which

supply our customers, and

have in excess of 275,000

individual analyses

performed by our

contracted analytical laboratories.

All our water quality monitoring and reporting is coordinated

through our Water Quality Management System. This software

provides many aspects of water quality management and acts

as the central database for all information on drinking water

quality including sampling program design, sampling analysis,

monitoring and reporting. The Water Quality Management

System also automatically issues alerts for results outside

guideline and operational limits and prompts remedial action.

Engagement with Department of Health

Department of Health is the regulator of drinking water quality

in Western Australia. In November 2007, we entered into our

third Memorandum of Understanding with the Department of

Health for managing drinking water quality, our area of

control. The Memorandum of Understanding connects all

facets of nationally and internationally recognised drinking

water guidelines, standards, and quality management

assurance systems. It requires us to notify the Department of

Health within 24-hours when any sample exceeds a set health

value or where any other event could pose a risk to public

health. The Department of Health reviews our monitoring

results and corrective actions. The current Memorandum of

Understanding

provides for the

Department of

Health to conduct a

performance review

of our systems and

databases used to

manage and report

drinking water

quality. In

consultation with the

Economic Regulation

Authority, the

Department of Department of Health, Department of Water

and Water Corporation at Victoria Dam



Health commissions audits to cover a three year period in line

with our Operating Licence audit. For more information on the

latest audit, please visit the Drinking water quality section of

our webpage www.watercorporation.com.au.

Incident response

We are committed to protecting our water sources and while

every effort is made to prevent water quality incidents from

happening, there will inevitably be times when issues may

occur. We have incident management plans and procedures to

manage any issues with the minimum possible impact on

water quality and our customers.

Gascoyne River floods, December 2010

http://www.watercorporation.com.au/about-us/our-performance/drinking-water-quality


We have three case studies which illustrate some of the

initiatives we have undertaken to improve drinking water

quality.

Case Study 1: Introduction to the Framework for

Management of Drinking Water Quality

Summary

The 2004 version of the ADWG endorsed a Framework for

Management of Drinking Water recommending a

comprehensive and systematic suite of day-to-day

management practices to ensure the supply of safe drinking

water to our customers. Since then we have implemented the

Framework as a basis for our Drinking Water Quality process

planning and management, as well as the driver of strategy to

reach our desired state.

This best practice Framework aims to assure drinking water

quality and protect public health through a risk prevention

approach encompassing all steps in water production and

supply from catchment to tap. It incorporates the appropriate

elements of the ISO 9001 Quality Management Standard, the

AS/NZS 4360:2004 Risk Management Standard and the

HACCP (Hazard Analysis Critical Control Point) system adopted

internationally by the food industry. The Framework applies

and tailors the key elements of these systems specifically to

the supply of drinking water.

Framework for Management of Drinking Water Quality

The 12 elements of this comprehensive Framework are shown

below.

Case Studies


Audit (Internal)

In response to the Framework’s formalisation in the ADWG an

internal auditing tool, AQUALITY, was designed by the

Australian water industry and produced by the Water Services

Association of Australia (WSAA). The tool is based on 196 sub-

element questions around the 12 elements in the Framework

and acts as a self-assessment for water utilities, allowing a

rating out of 100 for each element. The tool is a highly

valuable aid to our business of providing safe water to our

customers. The incorporation of the Framework within the

Drinking Water Quality Branch is also internally audited

through our Management Review and Audit Branch.

Audit (External)

The Water Corporation is externally audited every three

years by the Department of Health. Additionally, as part of

our Asset Management Branch’s external Aquamark audit in

2012, the International Water Association (IWA) and WSAA,

rated a key part of our Framework, the Water Quality

Management System, at 98 per cent. This was then written

up as an IWA/WSAA Leading Practice Case Study in the

WSAA Leading Practices Compendium.

Highlights

The Water Corporation uses AQUALITY continuously to assess

Framework implementation progress. A number of elements

have been assessed as “industry best practice” with key

examples given below.


Case Study 2: Source Protection Signage and

Barrier Project

Challenge

As a result of an internal audit of ‘Drinking Water Source

Protection Management’, we upgraded and increased source

protection barriers in country regions (including fences, gates

and signage) to meet the requirements of our Source

Protection Operations Manual (SPOM).

A number of regional drinking water catchments had

inappropriate, damaged or no signage to

• Mark the catchment boundary or prohibited zones

• Educate people on their presence within a catchment

• Inform the public of by-laws that apply, restricting

certain activities with the potential to contaminate the

water supply

• Inform the public where they can do certain activities

• Provide information on who to call in an emergency at

the site

Solution

In 2012/13 funding was made available under the Water

Quality Capital Improvement Program to:

• Purchase and install about 500 drinking water source

protection signs across the state.

• Manufacture and install swinging boom gates and

associated safety signs to prevent unauthorised access

to South West Region catchments by off-road vehicles.

• Upgrade security fencing and gates at high priority

sources in the Great Southern Region, including: - Two

People’s Bay (Albany), Jerramungup, Bottle Creek

(Narrogin), Gnowangerup, Ongerup and Pinwernying

Dam (Katanning).

Results

The majority of drinking water source protection signs have

been installed and those that remain, in the Mid West Region,

are generally in more remote locations and will be installed as

part of routine work over the next year.

Signage at Mount Magnet


The program of works to install swinging boom gates at our

catchments in the South West Region was completed in

September 2013. The Department of Parks and Wildlife

(DPaW) (formerly Department of Environment and

Conservation, DEC) approved the installation of all the

proposed gates in South West Region and understood their

value to protect the water supply.

Way forward

In addition to these barrier installations, there will be on-going

work to digitally record the location, condition and details of

these barriers across the state and integrate the information

into our corporate database. Regular inspections of the signs

will occur to check whether the signs are still legible to the

public.

Case Study 3: Feed Forward Control

Challenge

Over the past decade optimising the way in which our

treatment plants respond to changing water source quality has

been an ongoing challenge. Although the use of portable and

online sensor based global technologies has not advanced

significantly during this time, recent advances have been

made in the way in which we utilise this data. As a result, this

project aimed to increase control of our treatment plant to

maximise performance, minimise the use of treatment

chemicals and reduce operating costs, complementing our

“Reduce Reuse Recycle” key management priority.

Solution

An innovative movement towards using feed back control

loops has shown a revolutionary step forward in the way in

which we could operate treatment plants. This has meant, for

the first time, treatment operators can manage treatment

process conditions from a proactive rather than theoretical

reactive approach. This technology is based on integrating

portable online UV/Vis sensor technology (S::CAN) with

predictive coagulant demand software, controlling the

coagulation dose in a proactive (feed forward) way.

Picture of S::CAN Unit at Harding Treatment Plant


Results

In March 2010, the Mirrabooka Ground Water Treatment Plant

was selected as the test site to trial Feed Forward Control

capacity for advanced natural organic matter and dissolved

metals (Iron and Manganese) removal. In parallel with the

Water Quality Research Australia Project 1020, “Use of on-line

Surrogate Parameters for Rapid Hazard Detection and

Improved System Performance”, process performance for the

removal of natural organic matter (precursors of disinfection

by-products) was assessed.

Outcomes from this work were so successful that Feed

Forward Control was instated as a permanent operational and

process tool. A partial cost benefit analysis was performed

where initial cost impacts, covering the first 15 months of

operation under Feed Forward Control, showed significant cost

reduction per million litres (Chart 1). Furthermore, the

concentration of disinfection by-products in the reticulation

system were about 10 per cent lower, regardless of sample

point.

Way forward

After the successful trial and implementation of the system at

Mirrabooka Ground Water Treatment Plant, we have begun

Stage 2 of a trial at Harding Dam Water Treatment Plant.


Water treatment plants

The specific water quality of each source dictates the type of

treatment required. Where water comes from fully protected

catchment areas, very little treatment is required – just

disinfection. In other cases, more intensive treatment

processes may be required to ensure the drinking water

delivered to every house is safe and aesthetically pleasing.

Groundwater, which is pumped from underground aquifers,

can be treated to remove dissolved gases, iron, manganese,

colour and turbidity. In Perth, groundwater treatment plants at

Jandakot, Wanneroo, Lexia, Mirrabooka and Gwelup oxidise

the water (via aeration and/or chlorination) to increase the

amount of dissolved oxygen and remove both carbon dioxide

and hydrogen sulphide. A coagulant (alum) is also added, that

increases the settling of fine particles caused by iron and

natural organic matter. Clarified water then passes through

sand filters to remove any remaining particles. Similar

processes occur in many country supplies.

At Neerabup Water Treatment Plant, technology has been

introduced to soften the water and reduce salinity. This is the

first time this process has been applied in the southern

hemisphere, and reduces the problems of scale in kettles and

hot water systems, and soap that fails to lather. Naturally

occurring organic substances present a problem for many

water sources because they add colour to the water, which can

increase taste and odour and provide precursors for

disinfection by-products. Since 2001, we have used a water

treatment technology known as MIEX (magnetised ion

exchange) to prevent an intermittent “swampy” odour

occurring in treated groundwater supplied to Perth’s northern

suburbs. Unlike conventional processes, MIEX resin more

effectively removes dissolved organic carbon (DOC) from

drinking water, the source of the odour and taste concerns.

How is your water treated?

Schematic showing the MIEX treatment process


The schematic figure above shows how the resin mixes with

raw water in the stirred contactors. In the contactors, the

resin rapidly adsorbs DOC from the raw water. In the settler,

the resin (with attached DOC) is then separated from the

treated water. Since commissioning, the MIEX Treatment Plant

has provided a considerable reduction in swampy odour

contact from customers supplied from the Wanneroo

Groundwater Treatment Plant.

Desalination

Desalination, using reverse osmosis, has been used in Denham

for many years, to treat brackish groundwater. Reverse

osmosis was the desalination process chosen for both the 45

gigalitre per year Perth Seawater Desalination Plant, which has

been operational since November 2006 and the Southern

Seawater Desalination Plant, which began supply ahead of

schedule in September 2011.

Similar technology exists at

Leonora and Gascoyne Junction

to improve the aesthetic water

quality (hardness and total

dissolved solids). Other

methods of desalination

available include Electrodialysis

Reversal (EDR) installed at

Wiluna during 2009.

Ultra-filtration

Ultra-filtration treatment is a form of membrane filtration

where source water is forced through a semi-permeable

membrane. It is designed to remove suspended solids,

bacteria, viruses and other pathogens to produce water with

very high purity.

Ultra-filtration is being used at Wyndham, Harding Dam,

Pemberton, Denmark, Margaret River, Hyden, Walpole,

Gascoyne Junction, Salmon Gums, Greenbushes and Kirup.

Disinfection

Disinfection is our primary barrier against harmful pathogenic

bacteria and viruses in our water supply systems. Chlorination

is the most common form of disinfection we use, along with

other water utilities throughout the world. The chlorine dose is

maintained within a narrow range to ensure adequate

disinfection is achieved while only having a minimal effect on

the taste of our water.

Other forms of disinfection include chloramination and

ultraviolet light. Chloramination involves the use of chlorine

and ammonia to produce a longer lasting disinfectant.

Chloramination is used in the Goldfields and Agricultural Water

Supply Scheme to maintain a disinfectant residual along the

length of the extensive pipe network. Ultraviolet light is used

in combination with chlorination at some towns. Reverse Osmosis racks, Newman


Fluoridation

Public water supplies are fluoridated due to the properties of

fluorine which reduce dental cavities. Poor dental health is

extremely debilitating and remains a major public health

concern. Fluoride strengthens the enamel (surface) of teeth

making them more resistant to cavities.

In Western Australia, fluoridation is regulated by the

Fluoridation of Public Water Supplies Act (1966) which is

administered by the Department of Health. The Fluoridation of

Public Water Supplies Advisory Committee (FAC) oversees

fluoridation and makes recommendations to the Minister for

Health who may issue or rescind directives as appropriate.

To maximise the public health benefit from fluoridation the

FAC has initially sought to ensure larger towns with a

population exceeding 3,000 are given priority for fluoride.

Currently, over 90per cent of the state’s population receive the

benefits of fluoridation.

Dose rates have been set to provide consumers with a

prescribed amount of fluoride based on water consumption.

As average water consumption is proportional to ambient

temperatures different dose rates have been set out for

various parts of the state.

A maximum dose rate of 2 milligrams per litres (mg/L) is

prescribed in the Fluoridation of Public Water Supplies Act.

Notwithstanding the Act, the maximum health related criteria

for fluoride is 1.5 mg/L in the 2011 ADWG.

Most water supplies have some natural fluoride concentration

varying from less than 0.1 mg/L in surface waters through to

greater than 1.5 mg/L in some groundwater sources. Hence

the water fluoridation process involves adding or removing

fluoride to the necessary targeted fluoride concentration.

Fluoridated water supplies (see Table 1) are sampled at least

weekly to confirm acceptable fluoridation performance.

Fluoridation performance is reported monthly to the

Department of Health and periodically to the Fluoridation

Advisory Committee and the Advisory Committee for Purity of

Water.

Water fluoridation is supported by the World Health

Organisation, the Australian Dental Association, the Australian

Medical Association and the National Health Medical and

Research Council. Table 1 shows the localities and schemes

which we are required to fluoridate.


Table 1: Localities requiring fluoridation under Fluoridation of Public Water Supplies Act (1966)

Locality

Advisory Committee

recommended fluoride

range

Advisory Committee

recommended optimum

fluoride concentration

LocalityAdvisory Committee

recommended fluoride range

Advisory Committee

recommended optimum

fluoride concentration

Broome 0.6 - 0.8 mg/L 0.7 mg/L Buckland Hill 0.7 - 1.0 mg/L 0.9 mg/L

Derby 0.5 - 0.7 mg/L 0.6 mg/L Foothills 0.7 - 1.0 mg/L 0.9 mg/L

Dunsborough (de-fluoridated)* 0.7 - 1.0 mg/L 0.9 mg/L Greenmount 0.7 - 1.0 mg/L 0.9 mg/L

Esperance 0.7 - 1.0 mg/L 0.9 mg/L Greenmount/Darlington 0.7 - 1.0 mg/L 0.9 mg/L

Exmouth 0.6 - 0.8 mg/L 0.7 mg/L Hamilton Hill 0.7 - 1.0 mg/L 0.9 mg/L

Manjimup 0.7 - 1.0 mg/L 0.9 mg/L Harvey 0.7 - 1.0 mg/L 0.9 mg/L

Hills Direct 0.7 - 1.0 mg/L 0.9 mg/L

Kalgoorlie 0.7 - 1.0 mg/L 0.8 mg/L Lake Thompson 0.7 - 1.0 mg/L 0.9 mg/L

Merriden 0.7 - 1.0 mg/L 0.8 mg/L Lexia 0.7 - 1.0 mg/L 0.9 mg/L

Northam 0.7 - 1.0 mg/L 0.8 mg/L Mandurah 0.7 - 1.0 mg/L 0.9 mg/L

York 0.7 - 1.0 mg/L 0.8 mg/L Melville 0.7 - 1.0 mg/L 0.9 mg/L

Mirrabooka 0.7 - 1.0 mg/L 0.9 mg/L

Collie 0.7 - 1.0 mg/L 0.8 mg/L Mt. Eliza 0.7 - 1.0 mg/L 0.9 mg/L

Katanning 0.7 - 1.0 mg/L 0.8 mg/L Mt. Hawthorn 0.7 - 1.0 mg/L 0.9 mg/L

Narrogin 0.7 - 1.0 mg/L 0.8 mg/L Mt. Yokine 0.7 - 1.0 mg/L 0.9 mg/L

Mundaring 0.7 - 1.0 mg/L 0.9 mg/L

Albany 0.7 - 1.0 mg/L 0.9 mg/L Neerabup 0.7 - 1.0 mg/L 0.9 mg/L

Mt Barker 0.7 - 1.0 mg/L 0.9 mg/L Pinjarra 0.7 - 1.0 mg/L 0.9 mg/L

South Perth/Kewdale 0.7 - 1.0 mg/L 0.9 mg/L

Geraldton 0.7 - 1.0 mg/L 0.8 mg/L Tamworth Hill 0.7 - 1.0 mg/L 0.9 mg/L

Wanneroo 0.7 - 1.0 mg/L 0.9 mg/L

Karratha 0.6 - 0.8 mg/L 0.7 mg/L Waroona 0.7 - 1.0 mg/L 0.9 mg/L

West Yokine 0.7 - 1.0 mg/L 0.9 mg/L

Armadale/Kelmscott 0.7 - 1.0 mg/L 0.9 mg/L Whitfords 0.7 - 1.0 mg/L 0.9 mg/L

Bold Park 0.7 - 1.0 mg/L 0.9 mg/L

*Defluoridation is currently not covered by the Fluoridation Act. The recommended range and optimum concentration have been specified to provide a duty of care target.

Goldfields & Agricultural Water Supply Scheme

Great Southern Towns Water Supply Scheme

Lower Great Southern Towns Water Supply Scheme

Geraldton Regional Water Supply Scheme

West Pilbara Water Supply Scheme

Perth Integrated Water Supply Scheme


The following summaries are intended to assist you to

interpret the results presented in this report. Additional

information can be obtained by referring to the Fact Sheets

contained in the ADWG published by the National Health and

Medical Research Council and our website

www.watercorporation.com.au.

For the purposes of this report, all data are assessed in

relation to the ADWG.

Escherichia coli

Escherichia coli (E. coli) replaced thermotolerant coliforms as

the key indicator of microbiological performance during

2010/11. E. coli are a subgroup of thermotolerant coliforms

and a more specific indicator for faecal contamination. Any

detection of E. coli is responded to immediately to ensure

water supplied to customers is free of any potential

microbiological contamination.

Thermophilic Naegleria

Thermophilic Naegleria refers to a group of amoebae which

includes Naegleria fowleri, the organism that causes the

waterborne disease primary amoebic meningoencephalitis. In

the context of this report, Thermophilic Naegleria refers to

those tolerant to 42°C. Any detection of Thermophilic

Naegleria is responded to immediately to ensure the risk to

public health is minimised. For information on the Department

of Health’s Naegleria protocol please refer to their website.

Fluoride

Fluorine is one of the most

abundant elements in the

Earth’s crust, and is typically

found as the fluoride ion or

as organic or inorganic

fluorides. It is found

naturally in groundwater

supplies, and is present in

most food and beverage

products and toothpaste.

Additional fluoride is added

to a number of water

supplies in Western Australia

as directed by the Minister for Health (refer to “Fluoridation”

on page 29). The fluoride concentration after dosing is set by

the Fluoridation of Public Water Supplies Advisory Committee,

and does not exceed 1 mg/L. Notwithstanding this, the ADWG

health guideline for fluoride is 1.5 mg/L, applicable to both

fluoridated and non-fluoridated localities.

Nitrate

In Western Australia, elevated nitrate concentrations are

usually due to the natural process of plant decay underground

Fluoride injection point, Perth Seawater Desalination Plant

Understanding water quality test results

http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/eh52_aust_drinking_water_guidelines.pdf

http://www.watercorporation.com.au/faults/water-quality-issues

http://www.public.health.wa.gov.au/cproot/3649/2/Amoeba%20Response%20Protocol%20v3.pdf


that has occurred over geological time. The ADWG specify a

health guideline of 11.3 mg/L (measured as nitrogen) for

infants less than three months old and a guideline of 22.6

mg/L (measured as nitrogen) for adults and children over

three months old. Nitrate poisoning is very rare and to date no

case, due to nitrate in drinking water, has been recorded in

Western Australia. Where the nitrate concentration is between

11.3 and 22.6 mg/L, and there is no alternative supply, water

providers may apply to the Department of Health for an

exemption from the guideline.

The following localities have been granted exemption from

compliance with the nitrate guidelines by the Department of

Health:

• Mid West Region - Cue, Meekatharra, Mt Magnet,

Nabawa, New Norcia, Sandstone, Wiluna and Yalgoo.

• Goldfields and Agricultural Region - Laverton, Leonora

and Menzies.

In these towns, the Community Health Nurse provides advice

to nursing mothers regarding the use of alternative water for

the preparation of bottle feeds. We provide bottled water free

of charge via the Community Health Nurse as required.

Trihalomethanes

Trihalomethanes (THMs) are present in drinking water as a by-

product of disinfection using chlorination (and chloramination

to a lesser extent). We are required to comply with the ADWG

health guideline of 0.25mg/L expressed as an average long

term exposure. For the purposes of this report, THM

compliance is assessed comparing the guideline with the mean

annual THM concentration.

Alkalinity (as calcium carbonate)

Alkalinity is a measure of the parameters in water that have

acid-neutralising ability, typically expressed in mg/L of

equivalent calcium carbonate. Alkalinity can be affected by

naturally occurring minerals or water treatment chemicals.

There are no aesthetic or health considerations for alkalinity,

and therefore the ADWG 2011 do not provide any guideline

values.

Aluminium (acid-soluble)

Acid-soluble aluminium in water primarily originates from the

addition of coagulants such as aluminium sulphate or poly-

aluminium chloride in the water treatment process. These

coagulants are added to aid the removal of colour and

turbidity. Aluminium can accumulate in pipe sediments, and be

re-suspended during periods of rapid changes to flow patterns.

The ADWG specify an aesthetic guideline of 0.2 mg/L. No

health guideline is set.

Chloride


Chloride is present in natural waters from the dissolution of

salt deposits. In surface water, the concentration of chloride is

typically less than 100 mg/L while groundwater can have

higher concentrations, particularly if there is salt water

intrusion. In Australian drinking water supplies chloride levels

range up to 350 mg/L depending on local source

characteristics.

Chloride is essential for humans and animals. It contributes to

the osmotic activity of body fluids. Based on aesthetic

considerations, the chloride concentration in drinking water

should not exceed 250 mg/L (ADWG 2011).

Hardness (as calcium carbonate)

Hard water requires more soap to obtain a lather. It can also

cause scale to form on hot water pipes and fittings. Hardness

is caused by the presence of dissolved calcium and

magnesium. Water with hardness:

• Less than 60 mg/L is soft and possibly corrosive

(depends on pH, alkalinity and dissolved oxygen

concentration),

• Between 60 and 200 mg/L is deemed good quality for

all domestic uses,

• Between 200 and 500 mg/L will increase scale

formation and

• Greater than 500 mg/L will cause high scaling.

Hardness can be an important issue when purchasing

appliances such as dishwashers. To convert the hardness

values presented in this report to dH (German degree) units,

divide by 17.8. To convert hardness to millimol (mmol) units,

divide by 100 and to convert to milliequivalent (mEq) divide by

50.The ADWG specify an aesthetic hardness guideline of 200

mg/L.

Iron

Iron occurs naturally in water as a result of contact with soil or

rock in the catchment. It can accumulate in pipe sediments,

and be re-suspended during periods of rapid changes to flow

patterns. Elevated concentrations cause discoloured water and

can stain laundry. The ADWG specify an aesthetic guideline of

0.3 mg/L.

Manganese

Manganese in water can come from contact with soil or rock in

the catchment. It can accumulate in pipe sediments, and be

re-suspended during periods of rapid changes to flow patterns.

Elevated manganese can make water look black and stain

laundry. The ADWG specify an aesthetic guideline of 0.1 mg/L.

pH

pH is a measure of water acidity (pH 7 is neutral). The ADWG

specify a lower and upper aesthetic value of 6.5 and 8.5

respectively. The guidelines allow for a pH of up to 9.2 for new


concrete tanks and cement-lined pipes, which can significantly

increase the pH for a short period of time. Elevated pH is often

caused by calcium carbonate leaching from the protective

cement lining of the pipes after long transit times. This

characteristic is found at a number of localities on our large

water supply schemes. Where low pH is experienced, this is

typically a consequence of the source characteristic rather

than the influence of treatment. Buffering is a treatment

process that stabilises the pH of the water.

Silica

In Australia, dissolved silica can range between 0.6 mg/L in

some surface waters to 110 mg/L in ground waters. Dissolved

silica can precipitate on some surfaces forming a white

residue. In cases where customer complaints occur due to

scale build-up, water hardness and silica concentrations are

often identified as the primary cause. There is no adverse

health considerations associate with silica in drinking water,

but to minimise scale build up on surfaces silica should not

exceed 80 mg/L (ADWG 2011).

Sodium

Sodium is widespread in water due to the high solubility of

sodium salts and the abundance of mineral deposits. In major

Australian reticulated supplies, sodium concentrations range

from 3 mg/L to 300 mg/L. While sodium is essential to human

life, there is no agreed minimum daily intake level. Based on

aesthetic consideration the concentration of sodium in drinking

water should not exceed 180 mg/L (ADWG 2011).

Total Dissolved Solids

Total Dissolved Solids (TDS) consist of inorganic (natural) salts

and small amounts of organic matter dissolved in water. Total

dissolved solids comprise sodium, potassium, calcium,

magnesium, chloride, sulphate, bicarbonate, carbonate, silica,

organic mater, fluoride, iron, manganese, nitrate and

phosphate.

Water with low TDS can taste flat, while water with high TDS

tastes salty and causes scaling in pipes, fittings and household

appliances. The ADWG provide guidance in the palatability of

drinking water according to TDS concentration:

• Between 0 and 600 mg/L is good quality

• 600 to 900 mg/L is fair

• 900 to 1200 mg/L is poor, and

• Greater than 1200 mg/L, TDS is

unacceptable/unpalatable.

The ADWG guideline of 600 mg/L is based on taste.

True colour

Colour in water originates mainly from natural drainage

through soil and vegetation in a catchment. Corroding metal

pipes can also discolour the water, with iron producing a

brownish colour and copper a faint blue colour. The ADWG


specify an aesthetic guideline of 15 TCU (True Colour Units).

As a guide, 15 TCU is just noticeable in a glass.

Turbidity

Turbidity is the cloudy appearance of water caused by the

presence of suspended matter. The ADWG specify an aesthetic

guideline of 5 Nephelometric Turbidity Units (NTU) which is

just noticeable in a glass of water.

Summary table and sample groups

Appendix A contains a list of the constituents within the

metals, hydrocarbons, pesticides, radiological and chemical

(other) sample groups, and their respective guideline values,

and sampling location.


Health related performance

Again we have achieved excellent microbiological performance

in 2012/13 with 100 per cent of schemes complying with the

Escherichia coli requirement which is the most important

indicator of faecal contamination (see graph below).

Compliance with health-related chemical guidelines is also high

with 100 per cent of all schemes meeting the guidelines. As

most chemical guidelines are based on lifetime exposure and

have large safety factors, an occasional result outside the

guidelines does not mean the water is unsafe to drink. For this

report, compliance is met if the mean chemical concentrations

for the year are less than the guideline value.

However, if a sample result exceeds the maximum

concentration recommended in the ADWG, it is responded to

quickly and appropriate remedial action undertaken.

The Department of Health is notified of all exceptions and is

closely involved in the response process.

Non-health (aesthetic) related performance

While we strive to meet the ADWG for aesthetic

characteristics, this is very difficult to achieve in a state as

vast as Western Australia with a wide variety of water sources.

This is especially the case in some of our small country water

supplies where there can be few sources of drinking water

available and where installation of treatment can be very

costly. We are committed to improving all aspects of drinking

water quality, however, improvements in aesthetic water

quality are often hard to achieve. The State Government

(through the Ministers for Health and Water) has recognised

that meeting the aesthetic requirements of the ADWG will

require considerable expenditure and may take many years.

Detailed performance review for 2012/13

Performance at a glance


Appendix C shows a detailed summary of test results for each

scheme throughout the state. The following graph shows the

overall aesthetic performance for 2012/13. The left-hand bar

shows the percentage of 245 schemes where the mean

concentration for the year is less than the aesthetic guidelines.

In 2012/13, around 64 per cent (157 out of 245) of our

schemes met all of the aesthetic guidelines. The right-hand

bar shows our performance for all aesthetic analyses

(aluminium, true colour, hardness, iron, manganese, pH, TDS,

turbidity, sodium, chloride, sulphate and silica) across our 245

schemes. Our total performance was 95 per cent, with 10,297

out of 10,868 analyses complying with the aesthetic

guidelines.

The results in Appendix C show a relatively small number of

excursions above the guidelines in aesthetic quality. These

excursions are caused by the unique quality of local sources,

lack of alternative sources, impact of the drying climate on

groundwater production and abstraction from groundwater in

proximity to the coast.

For many schemes, these excursions have only minimal

influence on the taste of the drinking water.

The graph below shows the challenge of supplying

aesthetically pleasing drinking water to many smaller towns

with limited available water resources.


Health performance review 2009 to 2013

For the past five years, the microbiological performance has

been excellent with 100 per cent of the metropolitan and

country localities complying with the Escherichia coli (or

thermotolerant coliform) requirements. For chemical-health,

there is similar high performance over this period.


Customer contacts

Water quality related customer contacts (enquiries and

complaints) are recorded and monitored continuously to

identify any trends and areas for improvement. In 2012/13

our Operations Centre received 7,724 water quality related

customer contacts (compared with 7,898 in 2011/12). Below

shows the breakdown of these.

For customer contacts regarding poor water quality (water

quality faults) our Customer Charter states we will respond

within two hours or at an agreed time. We have an agreed

customer and business target of 95 per cent. In 2012/13 once

a fault was recorded we responded to 95.4 per cent within the

target of two hours (see figure below).

Customer research

Customer expectations


We measure community perceptions of the quality of their

drinking water through our quarterly Customer Performance

Index (CPI) survey. In this survey, customers are asked to

indicate the degree to which they either agree or disagree with

two statements in relation to water quality (where 1 is ‘poor’

and 10 is ‘excellent’). The average rating for these two statements in June 2013 was 7.1 and previous survey results

are shown below.

Survey Questions September 2012 December 2012 March 2013 June 2013

How would you rate the Water Corporation on

providing an acceptable standard of water quality?

6.7 7.2 7.2 7.0

How would you rate the Water Corporation on

providing a consistent level of water quality?

6.8 6.7 6.8 7.1

Average scores 6.8 7.0 7.0 7.1


Monitoring and reporting improvements

We have been strengthening our operational monitoring to

ensure continual barrier risk assessments, as prompted by the

ADWG revision. Extensive work has been undertaken on our

Locality Barrier Tool project which allows continuous visibility

of the critical processes during water treatment stages. Work

is still in progress but has already assisted in identifying areas

of progression for our capital project programs.

Water quality capital improvements

We have embarked on an extensive program of water quality

capital improvements. These projects ensure robust multiple

barriers to contamination are in place from “catchment to tap”

for all our schemes. Examples of work undertaken are

described through the following

sections.

Monitoring and control

systems

Installation of instrumentation

that allows continuous

monitoring of key water quality

parameters at each water supply

ensures unsatisfactory

performance is detected quickly

and remedial actions initiated.

Chlorination

We have begun a state-wide chlorination program to upgrade

all chlorinators to the latest corporate standards which

includes a body of work to modernise older chlorinators that

were not replaced in the original ADWG program.

Improvements will ensure enhanced alarming, automation and

reporting capability.

Water treatment

New treatment plants, and upgrades to existing plants,

continue to be installed in order to meet the lower chemical

concentrations recommended by the ADWG and to provide an

additional barrier to microbiological contamination.

Picton Water Treatment Plant was completed in 2012 and the

plant is now providing a significant contribution to the

Australind/Eaton schemes. The Picton plant is providing highly

treated water, importantly including iron removal to reduce

discoloured water, from a redeveloped Yarragadee bore.

Ensuring safe drinking water during times of crises

We have five mobile emergency ultra-filtration plants which

allow us to rapidly restore high quality drinking water supplies.

In the past, the only practical option was to transport drinking

water by road tankers to affected areas. These plants are

mobilised quickly to provide a minimum of 500,000 litres of

high quality water per day. Other treatment units are available

for specialised applications including a reverse osmosis unit. Water Corporation staff, Perth Seawater Desalination Plant

Improving your water quality


In 2012/13 mobile units were deployed in Salmon Gums,

Kirup, Greenbushes, and Gascoyne Junction. Units were also

deployed to Manjimup last summer but are now on standby for

the coming summer pending the final yield from this winter

and the impact of a new pipeline bringing water from a

Yarragadee Bore near Nannup.

Tank roofs

Construction, repair or replacement of roofs on all reservoirs

and tanks ensures stored water cannot be contaminated with

rainwater or pests and vermin.

Pipes and pipelines

Construction of new pipelines and modification to the flow of

water through tanks and reservoirs prevents stagnation of

water in storage.

Disinfection in long pipes

A major corporate project has been running for eight years to

improve the persistence of chloramine through the long

pipelines of the Goldfields and Agricultural Water Supply

(GAWS), the only chloraminated water supply system in

Western Australia. This has involved a series of detailed

investigations across the scheme. One component included

determining the areas of nitrification, which is when natural

aquatic bacteria within the pipelines convert ammonia to

nitrite, causing a reduction in the extent of effective

disinfection. We have been working internally, and with

Research Organisations to overcome this issue.

Measures that have been taken to expand the maintenance of

chloramine and chlorine residuals further into the distribution

system have included the installation of numerous chlorine

and ammonia dosing plants at strategic points in the system.

Modifications have also been made to many of the tanks by

installing specially designed separate inlets to each tank to

ensure complete mixing. This, together with operating at lower

water levels in the tanks during the winter low demand period,

minimises water stagnation and loss of residuals. These

measures have succeeded in significantly improving the water

quality of the supply on the GAWS.

Goldfields Pipeline


ConstituentHealth Guideline

(mg/L)Guideline Sampling Location Constituent

Health Guideline

(mg/L)Guideline Sampling Location

2,4,5-trichlorophenoxyacetic acid 0.1 2011 Reticulation System Fluometron 0.05 2011 Reticulation System

2,4-dichlorophenoxyacetic acid 0.03 2011 Reticulation System Heptachlor & heptachlor epoxide (total) 0.0003 2011 Reticulation System

Aldrin 0.0003 2011 Reticulation System Hexachlorobenzene * 2011 Reticulation System

Atrazine 0.02 2011 Reticulation System Hexazinone 0.3 2011 Reticulation System

Azinphos-methyl 0.003 2011 Reticulation System Lindane 0.01 2011 Reticulation System

Bromophos-ethyl 0.01 2011 Reticulation System Maldison 0.05 2011 Reticulation System

Chlordane 0.002 2011 Reticulation System Methoxychlor 0.3 2011 Reticulation System

Chlorothalonil 0.03 2011 Reticulation System Metolachlor 0.3 2011 Reticulation System

Chlorpyrifos 0.01 2011 Reticulation System Metsulfuron-methyl 0.03 2011 Reticulation System

Clopyralid 1 2011 Reticulation System Molinate 0.005 2011 Reticulation System

DDT (total isomers) 0.009 2011 Reticulation System Parathion-ethyl 0.01 2011 Reticulation System

Diazinon 0.003 2011 Reticulation System Parathion-methyl 0.1 2011 Reticulation System

Dicamba 0.1 2011 Reticulation System Picloram 0.3 2011 Reticulation System

Diclofop-methyl 0.005 2011 Reticulation System Propazine 0.05 2011 Reticulation System

Dieldrin 0.0003 2011 Reticulation System Propiconazole 0.1 2011 Reticulation System

Dimethoate 0.05 2011 Reticulation System Simazine 0.02 2011 Reticulation System

Diuron 0.03 2011 Reticulation System Terbutryn 0.3 2011 Reticulation System

Endosulfan 0.03 2011 Reticulation System Triclopyr 0.1 2011 Reticulation System

Ethion 0.003 2011 Reticulation System Trifluralin 0.05 2011 Reticulation System

Fenitrothion 0.01 2011 Reticulation System

Pesticides

* The guidelines state there is insufficient data to set a guideline based on health considerations

Appendix A – List of parameters

within sampling groups


ConstituentHealth Guideline

(mg/L)Guideline Sampling Location Constituent

Health Guideline

(mg/L)Guideline Sampling Location

Benzene 0.001 2011 Reticulation System Hexachlorobutadiene 0.0007 2011 Reticulation System

Carbon tetrachloride 0.003 2011 Reticulation System Nitrilotriacetic acid (NTA) 0.2 2011 Reticulation System

Chlorobenzene 0.3 2011 Reticulation System Organotins 2011 Reticulation System

Dichlorobenzenes 2011 Reticulation System Tributyltin oxide 0.001 2011 Reticulation System

1,2-dichlorobenzene 1.5 2011 Reticulation System Plasticisers 2011 Reticulation System

1,3-dichlorobenzene * 2011 Reticulation System di(2-ethylhexyl) phthalate (DEHP) 0.01 2011 Reticulation System

1,4-dichlorobenzene 0.04 2011 Reticulation System Polycyclic aromatic hydrocarbons (PAHs) 2011 Reticulation System

Dichloroethanes 2011 Reticulation System Benzo(a)pyrene 0.00001 2011 Reticulation System

1,2-dichloroethane 0.03 2011 Reticulation System Styrene (vinylbenzene) 0.03 2011 Reticulation System

Dichloroethenes 2011 Reticulation System Tetrachloroethene 0.05 2011 Reticulation System

1,1-dichloroethene (1,1-DCE) 0.03 2011 Reticulation System Toluene 0.8 2011 Reticulation System

1,2-dichloroethene (1,2-DCE) 0.06 2011 Reticulation System Trichlorobenzenes (total) 0.03 2011 Reticulation System

Dichloromethane 0.004 2011 Reticulation System Trichloroethylene (TCE or trichloroethene) * 2011 Reticulation System

Ethylbenzene 0.3 2011 Reticulation System Vinyl chloride 0.0003 2011 Reticulation System

Ethylenediamine tetraacetic acid (EDTA) 0.25 2011 Reticulation System Xylene 0.6 2011 Reticulation System

Hydrocarbons



In addition to the above specific analyses, screening for a

large number of other pesticides is undertaken on all samples

(refer Appendix B for full list). Any detection is further

analysed and the result reported to the Water Corporation.

Other Health-related Chemicals

This group currently includes Cyanide (health guideline of

0.08 mg/L) and Iodide (health guideline of 0.5mg/L).

ConstituentHealth

Guideline

(mg/L)

Guideline Sampling Location

Antimony 0.003 2011 Reticulation System

Arsenic 0.01 2011 Reticulation System

Barium 2 2011 Reticulation System

Beryllium 0.06 2011 Reticulation System

Boron 4 2011 Reticulation System

Cadmium 0.002 2011 Reticulation System

Chromium (as Cr[VI]) 0.05 2011 Reticulation System

Copper 2 2011 Reticulation System

Lead 0.01 2011 Reticulation System

Mercury 0.001 2011 Reticulation System

Molybdenum 0.05 2011 Reticulation System

Nickel 0.02 2011 Reticulation System

Selenium 0.01 2011 Reticulation System

Silver 0.1 2011 Reticulation System

Uranium 0.017 2011 Reticulation System

Zinc * 2011 Reticulation System

Metals



This appendix lists all constituents for which we routinely sample. Additional information is available by telephoning us on 13 13 75

Acrylamide Dichloromethane 2,4,5-trichlorophenoxyacetic acid Heptachlor & heptachlor epoxide (total)

Benzene Ethylbenzene 2,4-dichlorophenoxyacetic acid Hexachlorobenzene

Carbon tetrachloride Ethylenediamine tetraacetic acid (EDTA) Aldrin Hexazinone

Chloroacetic acids Epichlorohydrin Atrazine Lindane

Chloroacetic acid Hexachlorobutadiene Azinphos-methyl Maldison

Dichloroacetic acid Nitrilotriacetic acid (NTA) Bromophos-ethyl Methoxychlor

Trichloroacetic acid Organotins Chlordane Metolachlor

Chlorobenzene Tributyltin oxide Chlorothalonil Metsulfuron-methyl

Chlorophenols Plasticisers Chlorpyrifos Molinate

2-chlorophenol di(2-ethylhexyl) phthalate (DEHP) Clopyralid Parathion-ethyl

2,4-dichlorophenol Polycyclic aromatic hydrocarbons (PAHs) DDT (total isomers) Parathion-methyl

2,4,6-trichlorophenol Benzo(a)pyrene Diazinon Picloram

Dichlorobenzenes Styrene (vinylbenzene) Dicamba Propazine

1,2-dichlorobenzene Tetrachloroethene Diclofop-methyl Propiconazole

1,3-dichlorobenzene Toluene Dieldrin Simazine

1,4-dichlorobenzene Total Trihalomethanes Dimethoate Terbutryn

Dichloroethanes Trichloroacetaldehyde (chloral hydrate) Diuron Triclopyr

1,2-dichloroethane Trichlorobenzenes (total) Endosulfan Trifluralin

DichloroethenesTrichloroethylene (TCE or

trichloroethene)Ethion

1,1-dichloroethene (1,1-DCE) Vinyl chloride Fenitrothion

1,2-dichloroethene (1,2-DCE) Xylene Fluometron

Organic Compounds Pesticides

Appendix B – List of all sampling

parameters


Physical Characteristics Microbiological Radiological

Aluminium (acid soluble aluminium) Hardness (Ca, Mg) Escherichia coli Radium 226 & 228

Antimony pH Naegleria tolerant to >42°C Radon 222

Arsenic Total dissolved solids (calculated)

Barium True colour

Beryllium Turbidity

Boron

Cadmium

Chloride

Chromium (as Cr[VI])

Copper

Cyanide

Fluoride

Iodide

Iron

Lead

Manganese

Mercury

Molybdenum

Nickel

Nitrate / Nitrite

Selenium

Silicon

Silver

Sodium

Sulphate

Uranium

Zinc

Inorganic Chemicals


Perth Metropolitan Region

Health-related Tables 1 and 2

Aesthetic Tables 3 and 4

Mid West Region



Goldfields and Agricultural Regions



South West Region



Great Southern Region



North West Region



Appendix C – Summary of test

results


The information contained in the maps of this report is the exclusive

property of the Water Corporation and the respective copyright

owners. It is subject to ongoing review and should be viewed in

conjunction with the associated materials. No part of this production

should be copied, modified, reproduced or published in any form

other than that intended by the author. The respective data owners,

other than the Water Corporation, are acknowledged below:

Public Drinking Water Source Areas (Department of Water)

Hydrography Linear Hierarchy (Department of Water)

Road Centrelines (Landgate)

Townsites (Landgate)

Australian Coastline (Geoscience Australia)

The following metadata applies to all 6 maps:

Author: Drinking Water Quality Branch, Water Corporation of WA

Date created: 18 October 2013

Coordinate System: Geographic Coordinate System, GDA 1994

Vertical Datum: Australian Height Datum (AHD)

Original map names and AquaDoc numbers:

GAR_DWQB report map_v2.mxd (AquaDoc # 9510417)

GSR_DWQB report map_v2.mxd (AquaDoc # 9510418)

MR_DWQB report map_v2.mxd (AquaDoc # 9510420)

MWR_DWQB report map_v2.mxd (AquaDoc # 9510421)

NWR_DWQB report map_v2.mxd (AquaDoc # 9510422)

SWR_DWQB report map_v2.mxd (AquaDoc # 9510424)

Appendix D – Supporting information

for water source location maps

drinking water quality - water corporation · drinking water quality set by the department of...

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