power and water corporation DRINKING WATER QUALITY A POWER AND WATER CORPORATION ANNUAL REPORT 2011 DRINKING WATER QUALITYQUALIT Y ANNUAL REPORT 2011 Y Y SAFETSAFETY INTEGRITINTEGRITY we value we value TEAMWORK TEAMWORK COMMITMENT COMMUNICATION COMMUNICATION we value SAFETY power and water corporation DRINKING WATERW ATER QUALITYQUALITY 1 ANNUAL REPORREPORTT 2011

CONTENTS

From the Managing Director ...... 3

Section A: Framework for Drinking Water Quality Management ...... 4

1. Commitment to drinking water quality management ...... 6

2. Assessment of the drinking water supply system ...... 8

3. Preventative strategies for drinking water supply ...... 10

4. Operational procedures and process control ...... 13

5. Verification of drinking water quality ...... 14

6. Incident and emergency response ...... 16

7. Employee awareness and training ...... 16

8. Community involvement and awareness ...... 17

9. Research and development ...... 18

10. Documentation and reporting ...... 20

11. Evaluation and audit ...... 21

12. Review and continual improvement ...... 22

Section B: Drinking Water Quality and Performance ...... 25

Microbiological results summary ...... 25

Chemical and physical results summary ...... 29

Customer satisfaction ...... 32

Appendices ...... 36

Glossary of Acronyms ...... 42

Units of Measurement ...... 43

Standards ...... 43 we value SAFETY power and water corporation DRINKING WWATER ATER QUALITQUALITYY 3 ANNUAL REPORREPORTT 2011

FROM THE MANAGING DIRECTOR

PowPowerer anda nd WatWater er plays anan impor tant ta nt role in ensuring the safe andand sustainable supply of good quality drinkidrinkin ngg wawatterer forfor Terri Territtoriaorians.ns . We deliver water to customers across This Annual Report provides the 1.3 million square kilometres of further details on our water quality the Northern Territory, from the management system and the results Central Australian deserts to the of our water quality monitoring tropics of the north, in major centres for 2010-11. However, as our and remote communities. communities continue to grow and change, the Report also outlines our Our sources are as varied as priorities for future investment and underground aquifers that are more continual improvement. than 10,000 years old and above ground reservoirs that overfl ow nearly Work to raise the spillway of Darwin every year in the tropical wet season. River Dam, increasing its capacity by near 20 per cent was completed in Across these varied conditions, Power readiness for the 2010-11 Wet Season. and Water has an established program Investigations into returning Manton of monitoring at local water sources Dam to service as a surface water and throughout its distribution supply also continued this year. systems to ensure the quality of the water delivered to customers. These projects combined are part of a strategy to secure a quality water Multiple barriers against supply for the Darwin region in the contamination provide the maximum years to come. protection for water supplies and we continue to identify and carry Sustainable water supply continues to out suitable improvements to our be a priority for utilities across Australia systems right across the Territory. and Power and Water Corporation faces the same issues. These improvements include the installation of a second chlorination We will continue to work with our unit at Ti Tree, providing valuable communities to encourage responsible backup to the existing unit and use of this precious resource. improving security of safe supply.

ANDREW MACRIDES MANAGING DIRECTOR we value INTEGRITY

SSECTIONECTION A: FRAMEWORK FOR DRINKING WWATERATER QUALITYQUALITY MANAGEMENT

The Australian Drinking Water Guidelines (the 2004 ADWG) are the primary reference on drinking water quality in Australia. These Guidelines were published by a joint committee of the National Health and Medical Research Council (NHMRC) and Natural Resource Management Ministerial Council (NRMMC) in 2004. Based on the best available scientifi c evidence, these national guidelines provide a framework for good management of drinking water supplies and an authoritative reference on what defines safe, good quality water, how it can be achieved and assured. Power and Water is committed to providing safe drinking water by adopting and implementing the “Framework for Management of Drinking Water Quality” included as a key part of the 2004 ADWG. There are 12 elements to the Framework, which is based on a proactive approach to ensuring the safety of drinking water by managing all steps in water supply from catchment to consumer. The 12 elements are outlined in this report. A draft of the ADWG was released in 2009 and the NHMRC issued revised sections in draft form for public comment. The comment period closed on 15 January 2010. During the course of writing this report the new ADWG were released on 28 October 2011. In response this annual report has been extended to address changes to the Guidelines specifi cally the increased emphasis on multiple barriers and assessment of their performance. power and water corporation DRINKING WATERW ATER QUALITYQUALITY 5 ANNUAL REPORREPORTT 2011

ABOVE > DARDARWINWIN RIVERR I VER DAM SPILLSPILLWAYWAY IN FLOOD AFTER CYCLONE CARLOS FEBRFEBRUARY UARY 202011. 11. we value INTEGRITY

1. COMMITMENT TO DRINKING WATERW ATER QUALITQUALITY Y MANAGEMENT PowPowerer anda nd WatWaterer is committedcommitt ed tot o being a trusted providerpro vider of safe,goodsafe, good quality drinkingdrinking water . ThisThis is outlined in our DrinkingDrinking WaterWat er QualiQuality ty PolicyPolic y and Customer Contract. A copy of the Customer Contract is availabavailable l e at anyany PowerPowe r and Water Water officeofice f or at www.powerwater.com.auwww.powerw ater.com.au

While Power and Water has a primary the interest of public health. During responsibility for providing safe 2010 - 11, collaborative work continued drinking water through the Water between Power and Water and DoH on Supply and Sewerage Services Act, a Memorandum of Understanding for a number of government agencies Drinking Water (MoU). The MoU seeks are also involved. to define the roles, responsibilities, and obligations of both organisations with Department of Health (DoH) has a key the aim of improving drinking water role in applying the 2004 ADWG and quality management. The MoU was monitors compliance against them in approved in July 2011. power and water corporation DRINKING WATER QUALITY 7 ANNUAL REPORT 2011

ABOVE > MANTON RIVER RESERVOIR FROM DDARWINAR WIN RIVER RESERVOIR

The Department of Natural Resources, SUMMARY OF POWER AND • Implement any arrangements Environment, The Arts and Sport WATER’S DRINKING WATER notified by the Chief Health Offi cer (NRETAS) also has a role in protecting QUALITY POLICY in an emergency, to ensure the water quality, including the regulation safety of supply. We aim to provide our customers with and management of water resources a good quality, safe and reliable water • Respond promptly to any problem and the regulation of pollution control. supply. We will: identifi ed. The Department of Resources (DoR) • Supply drinking water, appropriate • Consult with the community where undertakes independent analyses of to the environment in which health-related physical, chemical or water samples in its laboratories in the community is located, in radiological parameters exceed the Darwin and Alice Springs. accordance with parameters Guideline value. The Department of Construction set by the 2004 ADWG. In May 2011 a review of the policy was and Infrastructure (DCI) also has a • Monitor the quality of drinking initiated. This will be completed in the major role in protecting water quality water in line with the Drinking first half of 2011 - 12. through land use planning. Water Monitoring Program and report the results to the Chief These agencies coordinate and Health Offi cer, DoH. cooperate to ensure highest standard of water quality is • Develop contingency and response achieved and maintained. plans to deal with incidents that may adversely affect drinking water quality. we value INTEGRITY

2. ASSESSMENT OF THE DRINKING WATERW ATER SUPPLSUPPLYY SYSTEM

PowPowerer anda nd WatWater er supplies wawatterer tot o five majormajor centres andand 14 minor centres illustrated in figure 1 below.below. FIGURE 1:1: POWER AND WATERW ATER CORPORATION WATERW ATER SUPPLSUPPLYYS SERVICE ERVICE AREAS

ARAFURA SEA

Melville Bathurst Island Island

COX PENINSULA ROAD

BATCHELOR ARNHEM HIGHWAY

KAKADU HIGHWAY TIMOR SEA PINE CREEK CENTRAL ARNHEM ROAD Groote Eylandt

GULF OF CARPENTARIA ROPER HIGHWAY

TIMBER CREEK LARRIMAH

VICTORIA HIGHWAY DALY WATERS

CARPENTARIA HIGHWAY TABLELANDS HIGHWAY TABLELANDS

NEWCASTLE WATERS ELLIOTT

BUNTINE HIGHWAY CALVERT ROAD

STUART HIGHWAY

BARKLY HIGHWAY TENNANT CREEK

TANAMITANAMI ROAD

DESERT TANAMI ROAD

QUEENSLAND

TI-TREE WESTERN AUSTRALIA AUSTRALIA WESTERN

SANDOVER HIGHWAY

PLENTY HIGHWAY KINTORE ROAD

ALICE SPRINGS

SIMPSON KINGS CANYON DESERT Water Supply Licence Area STUART HIGHWAY Water Supply Licence Area (Restricted Services Area)

YULARAA LASSETER HIGHWAY Water Supply and Sewerage Service Licence Area Major Urban Minor Urban SOUTH AUSTRALIA

Major centres have larger and usually This year Garawa, a town camp of from the Garawa supply. To assist the more complex infrastructures. Borroloola, is included in this report. Mabunji Aboriginal Resource Centre Power and Water provides the While the Mabunji Aboriginal Power and Water monitors Garawa technical services to maintain these Resource Centre is the custodian of the potable water quality by appending supplies. With these resources in Garawa water supply infrastructure it to the Borroloola water quality place, major centres are able to it is operated by Power and Water’s monitoring program. extend these services to minor centres Essential Services Officer (ESO) based functioning both as a technical and at Borroloola. The Borroloola ESO administrative hub. also collects routine water samples power and water corporation DRINKING WATERW ATER QUALITYQUALITY 9 ANNUAL REPORREPORTT 2011

TABLE 1: SUMMARY OF EXISTING DRINKING WATER SOURCES IN MAJOR AND MINOR CENTRES

Centre1 Source Adelaide River Ground water Alice Springs Ground water (Roe Creek borefield) Batchelor Ground water Borroloola2 Ground water Cox Peninsula Ground water Daly Waters Ground water Darwin Surface water (Darwin River Reservoir) + ground water (10%) Elliott Ground water Gunn Point Ground water Katherine Surface water (Katherine River) + ground water (30%) Kings Canyon Ground water Larrimah Ground water Mataranka Ground water Newcastle Waters Ground water Pine Creek Surface water (Copperfield Reservoir) + ground water (40%) Tennant Creek Ground water (Kelly Well, Kelly Well West and Cabbage Gum borefi elds) Timber Creek Ground water Ti Tree Ground water Yulara Ground water

1 With local names where in common use. 2 The water source for the Borroloola town camp Garawa is groundwater and is separate from the Borroloola source.

WATER SOURCES RAISING THE DARWIN RIVER DAM additional permanent water supply FULL SUPPLY LEVEL (EMBANKMENT for Darwin began in 2007-08. The primary water source for centres AND SPILLWAY WORKS) across the Northern Territory is ground Power and Water instigated the water. Exceptions are Darwin, Katherine A major project completed in bathometric measurement and and Pine Creek which also access 2010-11 increased the capacity modelling of Manton Dam Reservoir surface water. Table 1 lists existing of Darwin River Reservoir by and is currently investigating water sources for major and minor approximately 17 per cent. The “in reservoir” strategies for the centres in the Northern Territory. spillway was reinforced and raised improvement of water quality. This by approximately 1.3 metres. A work continued through 2010-11. Most of Darwin’s water supply comes prolonged Wet Season and from Darwin River Reservoir. To ensure record-breaking rainfall from Power and Water has developed a good quality water, no development or Cyclone Carlos caused the newly semi-quantitative risk assessment uncontrolled public access is permitted raised dam to spill for the fi rst method to identify and rank water within the catchment. The reservoir time on 16 February 2011. quality hazards posing risks to Territory is drawn down through the year with water supplies. This assessment is the majority of use in the Dry Season In a period of five days, the dam based on water quality measurements (May to October) with subsequent rose from 85 per cent of capacity to of health and aesthetic parameters recharging during the Wet Season 106 per cent of capacity. At this level taken in all centres from 2006 to 2011 (November to April). The balance of peak discharge was approximately and generates a score for each centre. supply (at least 10 per cent) is ground 11,000 mega litres per day or 25 per This score enables them to be ranked water from the McMinns and Howard cent of annual consumption. A special according to the scale of the risks and East borefi elds. investigation is currently operating to this information is used to allocate assess the impact of this project on resources to improve water quality. The water quality (refer page 18). assessment is presented in Section 12 Investigations into the use of - Review and continual improvement Manton River Reservoir as an (refer page 22). we value INTEGRITY

TThehe multiple barrier approach is uni versallyversally recognisedrecognised as the foundation forfor ensuriensuring ng safe drinkingdrinking water

3.PREVENTATIVE3. PREVENTATIVE STRATEGIES FOR DRINKING WWATER ATER SUPPLSUPPLYY Hazards may occur or be introduced throughout the waterwat er system andand preventiveprev enti ve measures as welw elll as the activities andand processes used toto control hazards should be comprehensivecomprehensive and have the capacity toto prprevevent hazardshazards or reduce them toto acceptable levelslev els from catchment to consumer.consumer . Preventive measures should focus A barrier may be comprised of pathogen contamination is inherently on catchments rather than rely on several components including: unsafe. Because pathogens are downstream processes. The extent • physical structures; efficiently disseminated via drinking of water treatment required is water throughout a community, • processes (which include determined by the effectiveness effective public health protection maintenance); and robustness of the measures must involve more than one barrier implemented to protect the water • policies; to disease transmission by this route. source. The signifi cance of the • engagement/agreement Pathogens have the potential to enter protection of water sources with stakeholders; a water supply at almost any point cannot be overstated. • legislation/ regulation; and within the system, therefore barriers Identification and implementation • assessment (to determine need to be present at all vulnerable of preventive measures requires effectiveness) sections of the water supply system. consideration of the important These barriers need to be robust to Power and Water has adopted the principle of the multiple barrier withstand the inevitable vagaries multiple barrier principle to protect approach. Many preventive measures of human error and the challenges drinking water supplies. The strength may control more than one hazard presented by nature and circumstance. of the multiple barrier approach is and some hazards may require more that a failure of one barrier may be In most water supply systems the than one preventive measure for compensated for by the remaining majority of barriers are placed effective control. The drinking water barriers, minimising the likelihood to protect against microbial system must have, and continuously of contaminants passing through contamination. maintain, robust multiple barriers the entire treatment system. The appropriate to the level of potential Table 2 summarizes the multiple multiple barrier approach is universally contamination facing the water barriers in place in major and minor recognised as the foundation for supply. The types of barriers required centres to mitigate hazards and ensuring safe drinking water. The and the range of preventive measures ensure the supply of safe placement of barriers in a conventional employed will be different for each drinking water. multiple barrier system is shown in water supply and determined by figure 2 below. characteristics of the source water and surrounding catchment. Microbial pathogens represent the most pervasive and consistent proven It is important to appreciate risk to drinking water safety. A drinking the barriers that comprise a water supply that is not explicitly and multi-barrier system are not effectively secured from potential restricted to physical barriers. power and water corporation DRINKING WATERW ATER QUALITYQUALITY 11 ANNUAL REPORREPORTT 2011

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ve ention

Barrier ev er Quality Back Flo Prevention PrPrevention Prevent introduction introduction Prevent Examples: • Pathogens • Chemicals Wat Management Objecti

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er Quality Z Barrier Barrier Residual Chlorine P Neutralise Neutralise microbiological througout hazards of hazards Example of hazards: Wat Management Objecti Water by SA original diagram Adapted from Objective Objective Objective systems • athogens

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er Quality Barrier eatment Tr Management Management Water Quality WatWater Management ObjectiObjective Remove most Remove Examples • Iron • Turbidity hazards hazards of hazards: • Pathogens oir v ve

er Quality Barrier Barrier Barrier Closed Chlorine Back Flow ReserReservoir Treatment Disinfection System Residual Manganese Hy Ir Minimise of hazards and of hazards hazards of hazards: introduction introduction some remove Examples Water Quality WatWater Management ObjectiObjective •• drocarbons and on

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er Quality Barrier Manganese Hy Ir Water Quality WatWater Management ObjectiObjective Minimise introduction introduction into of hazards water source Examples of hazards: • drocarbons •and on Catchments FIGURE 2: MULTIPLE BARRIERS AGAINST PATHOGENIC AND CHEMICAL HAZARDSCHEMICAL AND PATHOGENIC AGAINST BARRIERS MULTIPLE FIGURE 2: 2: MULTIPLE BARRIERS AGAINST PATHOGENIC AND CHEMICAL HA ARDS value value we

TWTABLEABLE 2: WATER ATER QUALITYQUALIT YB BARRIERS ARRIERS IN MAJOR AND MINOR CENTRES INTEGRITY

DDetention e te n t i o n CCoagulation, o a g u l a t i o n , MMaintenance a i n te n an c e DDisinfection i s i n fe c t i o n iin n rreservoirse s e r vo i r s BBore o re hhead e a d filfi ltration t ra t i o n oor r SStorage to ra g e ttankan k oof f ppositive o s i t ive BBack-fl a c k- flow ow reresidual s i d u a l to CaCatchment t c h m e n t aandn d pprotection ro te c t i o n BBore o re hhead e a d mmembrane e m b ran e iintegrity n te g r i t y and ppressure re s s u re ini n pprevention reve n t i o n iin n ccustomer’s u s to m e r’s CCentres e n t re s pprotection ro te c t i o n aaquifers q u i fe r s ZZone o n e iintegrity n te g r i t y filfi ltration t ra t i o n DDisinfection i s i n fe c t i o n ccleaning l e an i ng rereticulation t i c u l a t i o n rereticulation t i c u l a t i o n mmeter e te r Adelaide River Alice Springs Batchelor Borroloola Cox Peninsula N/A N/A Daly Waters Darwin Ground water Darwin N/A Surface Water Elliott Gunn Point Katherine Ground water Katherine N/A Surface Water Kings Canyon Larrimah Mataranka Newcastle Waters Pine Creek Ground water Pine Creek N/A Surface Water Tennant Creek Timber Creek Ti Tree Yulara

KEY Presence of Water Quality Barrier Absence of Water Quality Barrier power and water corporation DRINKING WATERW ATER QUALITYQUALITY 13 ANNUAL REPORREPORTT 2011

4. OPERATIONAL Power and Water’s systems and these systems can provide continuous processes are based on International monitoring for specific water quality PROCEDURES AND Standards Organisation (ISO) parameters such as chlorine, fl uoride, PROCESS CONTROL standards Environment (AS/ NZS conductivity, turbidity and pH. In-fi eld PowePowerr and Water ISO 14001:2004), Quality (AS/NZS measurements, such as temperature ISO 9001:2008) and Occupational and chlorine residuals help to identify has documented Health and Safety (AS/ NZS 4801:2001). performance issues and provide procedures in Power and Water continues to direction for corrective actions. routinely review and enhance its place toto ensure the Corrective and preventative actions systems and processes in accordance cover all aspects of operation and uninterrupted supply with Power and Water’s commitment include health, safety and quality. to continual improvement. of quality drinkingdrinking Corrective actions specifi c to a waterwater across the Operational monitoring is included procedure usually form part of that NorthernNor thernTerritory. Territory. as a component of Power and Water’s procedure. Corrective actions can be monitoring program and addresses linked to operational monitoring, Operators havehave chemical, physical and biological providing a formalised response to access toto these parameters relevant to water quality. deviations from set point values at critical control points. procedures via PowerPower To support the MoU between DoH and and Water’s intranet.intr a net. Power and Water Corporation for the Materials used by Power and Water management of drinking water quality, that contact potable water must Power and Water are continuing to comply with AS/NZS 4020:2005, develop the Protocol for the Notifi cation Testing of products for use in of Drinking Water Quality and Supply contact with drinking water Reportable Incidents and Events. This or other relevant standards. Protocol will ensure relevant persons Suppliers of chemicals used by are notified promptly of water quality Power and Water for water treatment incidents and events through a are required to provide an analysis structured and coordinated response. report of the chemical to be supplied. Critical control points in water supplies Chemicals must comply with the are monitored using a range of online relevant ANSI/AWWA standard and monitoring systems in each centre. the management system at the site of Apart from monitoring the status manufacture of the chemical must be and performance of infrastructure, certified to ISO 9001. we value INTEGRITY

5. VERIFICATION OF procedures are complex, protracted Power and Water introduced an and require a specific test for each extensive monitoring program for DRINKING WATER pathogen. The time taken for these N. fowleri in all major and minor QUALITQUALITYY analyses makes it impractical to centres in 2006-07 following the detection of this organism in South WATER QUALITY MONITORING directly test for pathogens, therefore indicator organisms are used to Australia and Western Australia. PowePowerr and Water determine if contamination with Monitoring was continued through designed andand faecal material has occurred. 2010-11 (refer page 28). implemented a The indicator organisms Power and The 2004 ADWG recommend an action Water monitors are: level of two N. fowleri organisms per 12 month monitoringmonitoring • Escherichia coli (or E. coli): indicates litre in the treated water system. program for the yeary ear faecal contamination from The 2004 ADWG also recommend 202010-11,1 0-1 1, which was warm-blooded animals, including controlling N. fowleri by maintaining submitsubm ittedt ed for approvalapproval humans and hence, the potential a minimum free chlorine level of for the presence of disease-causing 0.5 mg/L. Power and Water aims to to DoH in May 2010.2010. micro-organisms; and do this in all distribution systems Power and Water’s Drinking Water • Total coliforms: a range of bacteria except Tennant Creek where Monitoring Program 2010-11 is used found in many soil and aquatic continuous chlorination has to verify the effectiveness of water environments. Total coliforms provide not been implemented. quality management strategies. The a measure of the effectiveness of During the 2010-11 monitoring program is based on the 2004 ADWG’s the treatment system and a general period N. fowleri was detected in recommendations, however, knowledge indication of the cleanliness of the the Darwin supply. Details are of specific water quality issues for a drinking water supply. presented on page 27. water supply may require an increase The 2004 ADWG requires that for in monitoring frequency or monitoring Power and Water monitors for the assessment of microbiological of additional parameters. presence of Burkholderia pseudomallei performance: in reticulated water. B. pseudomallei Microbiological samples are collected • At least a minimum number of is the agent responsible for the from locations closer to the point routine samples have been tested disease melioidosis. This primarily of supply to the customer, typically for E. coli; and tropical disease causes a potentially from within the reticulation system • At least 98 per cent of scheduled fatal human infection that generally (e.g. from fire hydrants) or at samples (as distinct from repeat or manifests itself as a localised soft customers’ taps. Physical, chemical special purpose samples) contain tissue infection, pneumonia, abscesses and radiological properties are no E. coli. of the liver and spleen, or acute, rapid generally subject to less variation. and often fatal septicaemia. As a consequence, physical and The number of routine samples chemical samples are generally collected for E. coli testing is defi ned The monitoring program was collected from locations post-treatment in the 2004 ADWG and is based developed in 2006-07 in consultation while radiological samples are on the population served by each with the Department of Health and normally collected at sources. water supply. Community Services and focussed on the Tennant Creek water supply. The types of monitoring in the Power and Water monitors for the Monitoring was continued during program include: presence of Naegleria fowleri. N. fowleri 2010-11 (refer page 29). is a free-living ameboflagellate found MICROBIOLOGICAL MONITORING in soil and aquatic environments. CHEMICAL AND Waterborne disease-causing organisms This amoeba causes primary PHYSICAL MONITORING (pathogens) pose a serious risk to amoebic meningoencephalitis (HEALTH PARAMETERS) human health. The risk from pathogens (PAM), a very rapid and usually fatal Power and Water monitors numerous in water supplies can vary signifi cantly infection acquired when water chemical and physical parameters within a short period of time therefore contaminated with N. fowleri to ensure that water supplied to frequent microbiological monitoring enters the nasal passages. customers is safe to drink. is used to assess the potential for Testing for N. fowleri is included their presence. separately in the monitoring program The potential risk to human health increases as the levels of chemical The primary source of pathogens is as the indicator organisms described and physical parameters increase. faecal material either directly from above are not suitable indicators for Monitoring by Power and Water animals or from sewage. Pathogens are the presence of N. fowleri. difficult to detect and the analytical power and water corporation DRINKING WATERW ATER QUALITYQUALITY 15 ANNUAL REPORREPORTT 2011

ABOVE > DARDARWINWIN RIVER RESERVORESERVOIR I R IN FLOOD FEBRFEBRUARY UARY 202011 11 ensures any risk to human health is assess the results and examine pesticides were not detectable in any identified and quickly minimised. options to reduce the levels of water supply. More precisely, the level exposure (Secondary response level). of pesticides in all supplies was below The safe levels of these chemicals in the level of detection. In respect of drinking water are specifi ed in the Details of the radiological assessment these results, pesticide monitoring of 2004 ADWG, based on assumptions are reported on page 29. drinking water supplies during 2010-11 including water consumption and was restricted to Darwin and Katherine potential exposure to chemicals DISINFECTION BY-PRODUCTS supplies. The results for all samples from other sources. The results of Chlorine introduced into a water from these supplies were below the this monitoring is presented in supply as a disinfectant reacts with level of detection. the appendices tables A3 and A4 naturally occurring organic matter pages 38-41. such as decaying leaves and other CHEMICAL AND PHYSICAL MONITORING RADIONUCLIDES vegetation to produce several by-products of disinfection, primarily (AESTHETIC PARAMETERS) Radionuclides or radiation-emitting trihalomethanes (THMs). Numerous chemical and physical elements are sometimes found The concentration of THMs is typically parameters are monitored by Power in drinking water supplies. In the proportional to the amount of organic and Water in order to supply customers Northern Territory these elements material in the water. Surface water with aesthetically acceptable drinking are natural and characteristic of the supplies have higher levels of naturally water. Aesthetic parameters are the local hydrogeology. occurring organic matter than ground chemical and physical characteristics The 2004 ADWG defi ne corrective water supplies and hence higher THM of water quality which pose no threat action responses when guideline levels after disinfection. to human health but can affect limits are exceeded: drinking water appearance, taste, feel All major and minor centres were and odour. This includes total dissolved • If the total annual dose is less monitored for THMs in 2010-11 solids (TDS), hardness (calcium and than 0.5 mSv, Power and Water will as part of the Drinking Water magnesium carbonates and sulfates), continue monitoring in accordance Monitoring Program. with 2004 ADWG; colour, pH and a few common metals. • If the total annual dose lies between PESTICIDES The aesthetic quality will affect the 0.5 and 1.0 mSv, discussions should Pesticides (insecticides and acceptance of drinking water by the be held with the relevant health herbicides) are sometimes used in consumer and is usually the fi rst authority (DoH) to determine the our catchments to control insects change in water quality observed frequency of ongoing sampling and weeds. DoH requires testing for by the consumer. Results for the (Primary response level); and pesticides where there is the potential annual assessment of aesthetic • If the total annual dose exceeds for water supply contamination. parameters are shown in tables 1.0 mSv intervention is required. A3 and A4 pages 38-41. Results from the pesticide monitoring Power and Water and DoH should program from 2007-10 revealed that we value INTEGRITY

6.INCIDENT6. INCIDENT AND 7. EMPLOYEEEMPLO YEE OHS CONSTRUCTION INDUCTION WHITE CARD ‘WORK SAFELY IN THE EMERGENCY AWARENESS CONSTRUCTION INDUSTRY’

RESPONSRESPONSEE AND TRAINING The Northern Territory Code of Practice Appropriate andand PowePowerr and Water for Induction for Construction Work systematic responses ensures that alla ll commenced as an approved Code of Practice in the Northern Territory on to incidents that cancan emploemp loyyees ar are e 31 October 2009. Power and Water compromise waterwater appropriately trained has a legal obligation under the NT quality are essential and aware of their Workplace Health and Safety Act for the health and safety of its employees as in order toto protect rresponsibilities.esponsibilities . well as contractors performing works publicpublic health andand Procedures aandnd at its various work sites. Power and Water initiated the identifi cation and prprovideo vide best serservice vice documentation areare training of all relevant employees in to customers.customers. frequentlyfrequent l y revirevie ewwed anda nd relation to this legislative requirement A response procedure approved by the training requirements and set an initial completion date Chief Health Officer DoH, exists for are identified aandnd for 1 September 2010. The majority of any microbiological levels that exceed Power and Water’s Water Services staff the agreed limit. Power and Water programmed intointo completed this requirement in the responses include re-sampling, mains schedulesschedul es.. TrTrainingainin g is 2010-11 reporting period. flushing and manual disinfection continually monitored toto WATER SERVICES ESSENTIAL of storage tanks with sodium ensure staff knowledge SERVICE OPERATOR (ESO) hypochlorite. DoH is notifi ed promptly TRAINING COURSE of any substantial microbiological and skills are current. failure and the management of more Training course was held in Katherine serious incidents may trigger the use TRAINING TO NATIONAL for the Katherine Region ESOs in of Power and Water’s Corporate Crisis STANDARDS November 2010. The course focused and Recovery Manual. The Power and Water Corporation is primarily on chlorine awareness, dosing system checks and chlorine Emergencies and incidents during committed to gaining industry training measurement, safety and water quality. 2010-11 year are reported on page 35. to either Certificate III or IV for all the Water Operators. Certificates III and IV In April 2011 the Water Industry in Water Operations provide training Operators Association presented a for operators in the water industry seminar to Power and Water’s Water and the opportunity for specialisations Services’ staff titled Water Quality in water treatment, wastewater Awareness and Distribution System treatment, water supply distribution Management. Valuable knowledge (network), trade waste, catchment was shared with Water Service’s operations, irrigation, dams safety, staff and the concept of disinfection dams operations and source protection, performance assessment presented river groundwater diversions and in this seminar has been adopted by licensing, and construction and the Power and Water’s Water Quality maintenance. Section and will be the subject of an investigation over the next 12 months. power and water corporation DRINKING WATERW ATER QUALITYQUALITY 17 ANNUAL REPORREPORTT 2011

FIGURE 3 8.COMMUNIT8. COMMUNITYY AN EXAMPLE OF AAT TYPICAL YPICAL NEWSPAPER INVOLVEMENT ADVERTISEMENT INFORMING CUSTOMERS AND AWARENESS OF WATER QUALITQUALITY Y ISSUES PowePowerr and Water seeks community POWER AND WATER CORPORATION ininvolvementv olvement in andand Tennant Creek water supply awareness of water quality issues.issues. As part of Power and Water's efforts to maintain a healthy drinking We would like the community to: water supply, frequent and comprehensive tests are conducted on • Understand issues associated with Tennant Creek’s non-disinfected water supply. their drinking water quality; and Recent water quality indicators highlighted potential risks. As a result • Help Power and Water ensure the Power and Water initiated manual dosing of chlorine from 1 to 17 May in security and integrity of their supply the Cabbage Gum Borefield storage facility. by reporting: Chlorine is used in small amounts in accordance with the Australian – problems with water quality; Drinking Water Guidelines to disinfect the water and prevent disease. – damage to water supply or sewage For more information, visit powerwater.com.au/waterquality infrastructure; or call 1800 245 092. – suspicious activity or unauthorized access to powerwater.com.au | Call 1800 245 092 Power and Water’s facilities. Water quality specialists visit schools if requested and present classes on water science and other water-related subjects. Information on this, as well as our previous water quality reports, can be viewed at www. powerwater.com.au Customers are informed of current and predicted water quality issues through placement of newspaper advertisements. In Darwin advertisements are placed to inform customers of predicted seasonal water quality changes that may produce discoloured water. In Tennant Creek advertisements are placed to notify customers that risks identified during routine monitoring are to be remediated by manual dosing of the supply with chlorine. we value INTEGRITY

Power and Water sponsors various Power and Water Managing Director community activities and technical Andrew Macrides is Power and Water’s events to promote awareness of industry membership representative water quality by: for WQRA. • Sponsoring the Water in the Bush Power and Water, as a member of conference hosted by the Northern WQRA, plays an active role in the Territory branch of Australian Water Regional and Rural Water Supplies Association (AWA); Program. This program aims to: • Providing grants as part of • Address key issues that impact the annual Power and Water on the provision of good quality Melaleuca Awards; drinking water to regional and rural • Staging open days at facilities communities in Australia; such as Darwin River Dam; • Identify research that will provide • Making presentations at major affordable and sustainable solutions events including regional shows, to water supply problems; the Tropical Garden Spectacular • Help represent regional and rural in Darwin and the Sustainability water supply areas in setting Festival in Alice Springs; and industry policy, regulation and • Publishing pamphlets to promote strategic directions. better understanding of the Power and Water maintains direct Territory’s various water issues. involvement in a range of research projects to improve water quality 9.RESEARCH9. RESEARCH AND throughout the Territory. DEVELOPMENT Power and Water has also WaterWater QualQuality ity commissioned a number of Research Australia internal and external reports on water quality issues during 2010-11. Limited (WQRA) is a national research MANTON RIVER RESERVOIR RETURN TO SERVICE centre established • Altering the consecution of This is an internal Power and phytoplankton populations during to succeed the Water project. the year; CooperatiCooperativeve Research • Precipitation of iron and manganese During 2010-11 Power and Water by oxidation: and Centre (CRC) for Water continued to investigate seasonal Quality andand TrTreatment eatment water quality trends in Manton • Displacement of low quality water in River Reservoir. deeper sections of the reservoir with when the CRC ended rainfall infl ow. on 30 June 2008. The study focused on water quality variation through the water column DARWIN RIVER RESERVOIR WQRA undertakes collaborative and seasonal algal population MONITORING PROGRAM research of national application on trends, specifically blue green In 2010 Power and Water increased drinking water quality, recycled water algae (cyanobacteria) populations. and relevant areas of wastewater the level of the spillway at the dam by management. Modelling of seasonal vertical 1.3 metres with a resultant increase hydraulics has been completed in its capacity of approximately 17 per The main focus of the research in preparation for artifi cial cent and its surface area of 20 per cent. program is on urban water issues mixing of the reservoir. The increase in surface area constitutes related to public health and a significant inundation of surrounding Artificial mixing by aeration has the acceptability aspects of water supply, vegetation with obvious potential capacity to signifi cantly improve water recycling and aspects of water quality issues. Following the quality of water in Manton wastewater management. WQRA also unprecedented rainfall in early 2011, River Reservoir by: has an education program, utilising Darwin River Reservoir fi lled to the the most successful elements of the new capacity shortly after completion CRC program. of the infrastructure, elevating the risks to water quality. power and water corporation DRINKING WATERW ATER QUALITYQUALITY 19 ANNUAL REPORREPORTT 2011

ABOVE > DOWNSTREAM FROM DARWINDAR WIN RIVER DAMDOOWAM OVERFLOW VERFL .

This project is a 12 month limnological TOXIC CYANOBACTERIA UPDATE Project outcomes: monitoring program to assess any WQRA 1022 – Cyanosurvey – A National • Within two years, produce up-to-date changes in Darwin River Reservoir Update on Toxic Cyanobacteria and data on toxic cyanobacterial species that might impair water quality in their Distribution 2009-11 is an external and strain distributions in Australia; the supply source due to the water quality project supported by • During the project, provide a series increase in the spillway height. Power and Water. of reports to individual industry Water quality parameters may include partners on their specific risk profi les This project will: but have not been confi ned to: from toxic cyanobacteria; • Identify changes in distributions of • colour; • At the end of the project (two years) cyanobacterial species since 1991 in report on the changes that have • turbidity; order to support an up-to-date risk occurred in the Murray-Darling Basin • iron and manganese; assessment and help predict future since 1991, with trend analysis to trends in species distribution and • changes in the seasonal support conclusions about future changes in toxicity; concentrations and ratios of changes due to climate change; and nutrients; • Cross-validate a range of analytical • Extrapolation of conclusions to the methods for detection of toxic • algal biomass of dominant groups national level where possible, and to species and toxin production; and including Botryococcus braunii; and the local level when project fi ndings • aquatic and terrestrial weeds • Develop a compendium of can be integrated to historical specifi cally Olive hymenachne and national data on cyanobacterial monitoring data. Mimosa pigra. species and strain distribution, linking water quality parameters, This project concludes December 2011. toxicity, morphology and genetic characterisation to support current risk assessment and future climate change studies. we value INTEGRITY

1010. . DOCUMENTATION Operational data from the online (WIMS) was completed by the Asset monitoring supervisory control and Management Capability Project AND REPORTING data acquisition system (SCADA) is steering committee last fi nancial year. TThehe majority of made available to operators through a IBM was announced as the successful Power and WaWater’s te r’ s data historian application. This process tenderer in September 2009. IBM information system (PI System) allows Maximo Asset Management and ESRI documentation andand operators to record, analyse, and will replace the current WIMS and rrecordsecords are stored monitor the real-time status of water FIS applications. Development and electronicallyelectronical ly.. supply infrastructure and water quality. testing was undertaken during 2010 - 11 with implementation Research and development data is Power and Water’s Integrated planned for the 2011 - 12 year. Management System (IMS) maintained in Power and Water’s integrates all of Power and Water’s electronic data management The Asset Management Capability systems and processes into one system (TRIM). Project is critical to Power and Water to ensure: complete framework, enabling the Technical and operational details organisation to work as a single unit of the water supply system including • There is a consistent approach with unifi ed objectives. technical drawings and maps to managing assets; Core components of the IMS are the are contained in the Facilities • Data is accurate, complete and maintenance of documentation and Information System (FIS). regularly updated; the dissemination of information All of the above information is • The current outdated and infl exible through a formalised reporting system. accessible through the Power systems WIMS and FIS are replaced; and Data generated from the drinking and Water intranet. • Greater focus on maintenance water quality monitoring program The evaluation of replacement planning and reporting is needed. is maintained in a purpose-specifi c systems for the current FIS and Work Oracle database. Information Management System power and water corporation DRINKING WATERW ATER QUALITYQUALITY 21 ANNUAL REPORREPORTT 2011

ABOVE > NEWLNEWLYY RAISED SPILLSPILLWAYWAY AT DDARWIN AR WIN RIVER DAM 20201111

Maximo will enable customer service supplied to consumers, regulatory The preparation of the Annual to systematically record customer bodies and stakeholders. Drinking Water Quality Report 2011 queries and complaints. Power and is a valuable component of the The intrinsic relationship between Water’s Water Quality Section has review and evaluation process. Audits potable water and public health constructed call scripts that will ensure ensure that operational procedures means Power and Water and DoH correct categorisation of complaints and processes are in place so that share common responsibilities and received from customers and simplify accurate water quality data is collected are required to work together to the collation of this data in preparation and appropriate management systems resolve water quality health-related for the submission to the National are maintained. issues. Protocols are in place to Performance Report (NPR). ensure any exceedance of the 2004 Power and Water’s certifi cations to Power and Water provides information ADWG is reported promptly to DoH ISO 9001 (Quality Endorsed Company), to the public via its website. This by Power and Water. AS/NZS 4801 (Occupational Health includes technical information, guides and Safety) and ISO 14001 (Certifi ed to water conservation and media 11. EVALUATION Environmental Management) require releases. Power and Water reports to six monthly independent external the National Water Commission and AND AUDIT audits. The 2011 audit was conducted the information provided forms part of TheThe evaluatione v aluation andand in May by SAI Global. the National Performance Report (NPR) audit of PowerPower and Information obtained from these and affords the Northern Territory and audits and annual reports have Australian public with a reliable and Water’Water’ss WaterW ater Quality led to more comprehensive and transparent source of information on Management System targeted reforms to the Drinking urban water utilities. ensures successful Water Monitoring Program which Power and Water’s Annual Drinking mamanagementnagement of contribute to our program of Water Quality Report 2011 provides continual improvement. an objective account of the quality watwaterer quality datadata of Northern Territory potable water and processes.processes. we value INTEGRITY

12. REVIEW AND • Aquality – Elements 10, 11 and improve long term protection of the 12 of the 2004 ADWG; water supply for the community of CONTINUAL Tennant Creek. IMPRIMPROVEMENT O VEMENT • Case studies of water quality incidents; Power and Water continues to work PowePowerr and Water • Delivery of major projects with DoH to review disinfection is committedcommitt ed tot o addressing water quality issues. practice in Tennant Creek and routinely publishes a monthly dedevelopingv eloping andand REVIEW OF DRINKING WATER public notice highlighting imprimprovingo ving its drinkingdrinking QUALITY SYSTEM manual chlorine dosing practice. waterwater quality This report has a significant role in MICROBIOLOGICAL RISKS managementmanagement system the identification of water quality issues and helps to identify where N. fowleri presents a signifi cant health and the safety of operational and management system risk to consumers. To control this risk, drinkingdrink i ng waterwater supplies.supplies. improvements are required. Power and Water has set a minimum free chlorine residual of 0.5 mg/L to In early 2011 a new position of Water MICROBIOLOGICAL WATER QUALITY be maintained in all supplies at all Quality Information Management times. The effectiveness of this control Officer (WQIMO) was recruited to the Microbiological water quality is can be assessed by monitoring the Water Quality Section, This position is assigned the highest precedence free chlorine residual and recording to ensure water quality results from and is assured by assessing the all incidents where the free chlorine laboratories are scrutinized prior to number and effectiveness of residual falls below 0.5 mg/L. In a water transfer into the database. The WQIMO barriers that prevent the introduction supply the ability to maintain a free also reports on the execution of the of disease-causing organisms. chlorine residual above 0.5 mg/L is a monitoring program by documenting Table 2 shows Tennant Creek has direct measure of the ability to control sample collections and submissions, the least number of protective the N. fowleri risk in that supply. significantly reducing sample barriers therefore is monitored more collection failures. frequently to ensure system security. Maintaining a minimum free chlorine residual of 0.5 mg/L has the inevitable The WQIMO is also responsible for A referendum held on Saturday, consequence that the free chlorine the development of the Water Quality 29 May 2004 in Tennant Creek level will frequently exceed the Monitoring Data Management Manual. resulted in a strong community rejection of chlorination as a means aesthetic guideline value of 0.6 mg/L. This manual outlines the process of disinfecting the drinking water Free chlorine has therefore been required for validating water (75% against, 25% for). excluded as an aesthetic parameter quality data for entry into the in the risk assessment. water quality database. Validation Power and Water maintains that Although Tennant Creek has no of data is a key aspect of quality continuous chlorination is the significant chemical, physical management ensuring accuracy preferred method to disinfect drinking or radiological risk factors, the and constancy of records. water and that without it there exists an elevated and unnecessary level of greatest risk to this water supply is Power and Water has formed a risk to public health which must be microbiological as this supply does Water Quality Network with SA accepted. However, Power and Water not have continuous chlorination. Water (South Australia) and Water respects that the people of Tennant Power and Water continues to work Corporation (Western Australia). The Creek have voiced their opinion with DoH to review management of network provides a forum to share strongly against chlorination. microbiological risks and is considering information, knowledge and discuss the introduction of an Ultra Violet emerging issues. This allows us to A significant improvement in Tennant disinfection system. benchmark our performance and Creek microbiological water quality identify other ways to improve drinking was reported for the 2010-11 period water quality. The network group with more than 98% of programmed met in Adelaide in April 2011 and was samples free from E. coli. However, attended by Water Services’ staff. failures due to E. coli are still remediated by manual dosing storage The topics addressed at the tank water with sodium hypochlorite meeting were: and flushing the reticulation system. • Specifi c water quality challenges This approach is not an appropriate to each water utility; long term solution and does not power and water corporation DRINKING WATERW ATER QUALITYQUALITY 23 ANNUAL REPORREPORTT 2011

INFRASTRUCTURE DEVELOPMENT replaced. As part of the same project The values of each of these risks are Power and Water completed the new pumps were installed at Cabbage then summed and a final risk value refurbishment of the Katherine Gum to supply the distribution tanks. for that water supply obtained. Inlet and outlet pipe work on the water treatment plant sand fi lters in The risk calculation is based on distribution tanks was upgraded March 2011. This project included the the 95th percentile for chemical to improve displacement of water replacement of filter sand and nozzles, health parameters and average through the tanks. Modifications to the structural repairs, and replacement of concentration for aesthetic values. tank pipe work included connection auxiliary equipment. The project was The percentile is a value calculated points for the anticipated installation undertaken to improve the plant’s from a set of measurements. The of a UV disinfection system. efficiency including improvements percentile dictates what percentage in water quality. CHEMICAL, PHYSICAL AND of all the measurements are below The drilling of a new borefield at Elliott RADIOLOGICAL RELATIVE RISK this value. The 95th percentile is the was completed in July 2010 providing ASSESSMENT value below which 95 per cent of the measurements are found. four new production bores. Septic A risk assessment procedure has been systems located within the protection developed to prioritise improvements If a valid 95th percentile is not available zone of the original borefi eld are in chemical and physical water quality. the maximum value is used. The total believed to be the primary cause of It focuses on a scoring system for risk value for each water supply is microbiological water quality failures centres that exceed the 2004 ADWG compared to the total risk value of all in the Elliott supply. This new water values for one or more chemical, other water supplies. The results are source also addresses the issues physical or radiological parameters. then compiled to rank water supplies of elevated hardness and iodide in according to the scale of the risks from the original source. These bores are Power and Water combines likelihood highest to lowest. scheduled to be brought online in 2012. and consequences to assess risk. The likelihood of a parameter resulting in a This method provides a means for Elevated levels of iron and manganese problem is assumed to be proportional determining priorities for further in the Adelaide River water supply to the ratio of the annual assessed action. Actions may include collection often exceed the 2004 ADWG aesthetic value to the 2004 ADWG value. That of additional water quality data, value. Customer complaints relating to is, where the annual assessed value carrying out more detailed studies, or discoloured water, in particular staining exceeds a guideline value by double, investigation into alternative sources of laundry, increased during the 2010-11 the likelihood is given a value of two. of supply and water treatment options. period. The current system employed to minimise this problem is sequestration The consequence of any exceedance Table 3 shows Kings Canyon, and of the iron and manganese with is given a weighting according to its Timber Creek have the highest sodium silicate. The aim has been effect on human health. Weightings risk scores. to prevent the iron and manganese were developed in conjunction with The primary water quality issue for precipitating out of the water at the the DoH’s predecessor the Department Kings Canyon is iodide which is greater consumer’s tap. As the sequestration of Health and Community Services and than four times the 2004 ADWG value. of iron and manganese has only been are as follows: In the 2011 ADWG, the health guideline partly effective, Power and Water has • Relatively signifi cant health value for iodide has been raised from commissioned a consultant to design a impact: 10; 0.1 mg/L to 0.5 mg/L. In this report, water treatment plant for the Adelaide • Relatively minor health impact: 5; the 2010-11 ADWQR, the level of iodide River supply that will remove the iron and reported for the Kings Canyon’s water and manganese before water enters supply is 0.43 mg/L. Although this level • Relatively signifi cant aesthetic the distribution system. Construction exceeds the 2004 ADWG value it would impact: 3. should commence in the second half not exceed 2011 ADWG value. of 2012. For example, under this system arsenic Five other of the 19 water supplies have is given a weighting of 10 and salinity Infrastructure improvements to the slightly elevated levels of iodide. Tennant Creek water supply were (TDS) is given a weighting of 3. The primary water quality issues completed in 2010-11. For each water supply the risk for Timber Creek are barium and contributed by each parameter To allow repairs and routine cleaning lead which are approximately exceeding the 2004 ADWG value of the Cabbage Gum ground level tank twice 2004 ADWG value. the decommissioned elevated tank was is calculated. we value INTEGRITY

TTABLEABLE 3: RELATIVE RISK SCORING FOR ALL WATERW ATER SUPPLIES 202010-111 0-1 1

Rank Centre Relative Risk Score Parameters Exceeding 2004 ADWG aandnd DoH TDS Value 20102010 -11 1 Kings Canyon 44.1 Chloride, Hardness, Iodide, Lead, TDS 2 Timber Creek 38.1 Barium, Lead, Hardness 3 Daly Waters 33.2 Chloride, Hardness, Iodide, Sodium, TDS 4 Adelaide River 30.2 Chloride, Hardness, Sodium, TDS, Iodide 5 Tennant Creek 23.3 Fluoride, Iodide 6 Ti Tree 17.3 Hardness, Iodide, Nitrate 7 Elliott 11.9 Hardness, Iodide, 8 Pine Creek 11.0 Arsenic, 9 Larrimah 10.7 Hardness, TDS 10 Mataranka 10.3 Hardness, TDS 11 Yulara 5.2 Nitrate 12 Newcastle Waters 4.4 Hardness 13 Alice Springs 3.2 Hardness 14 Borroloola 3.0 pH 15 Batchelor 0.0 None 16 Cox Peninsula 0.0 None 17 Darwin 0.0 None 18 Gunn Point 0.0 None 19 Katherine 0.0 None

FIGURE 4:4 : RELATIVE RISK SCORES SHOWING CONTRIBUTING PROPORTIONS FROM HEALTH AND AESTHETIC PARAMETERS FOR 202010-111 0-1 1

Total Health Aesthetic 45.0

40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0

RELATIVE RISK 0.0

ree i T Waters River T Elliott Yulara Creek Waters Darwin Canyon Larrimah Springs Borroloola Batchelor Katherine Daly Pine Creek Mataranka Peninsula Alice Gunn Point Kings Timber Adelaide Tennant Creek Cox Newcastle CENTRE power and water corporation DRINKING WATERW ATER QUALITYQUALITY 25 ANNUAL REPORREPORTT 2011

S:SECTIONECTION B:B DRINKING WWATER ATER QUALITQUALITYY AND PERFORMANCE

MICROBIOLOGICAL system to determine the quality supply system to have zero indicator of water received by consumers. bacteria at all times. It is common in RESULTS SUMMARYSUMMARY The possibility for water quality to most water supplies that: BACTERIA diminish increases the further into • at times E. coli maybe detected the distribution system it travels. A and remedial action required; MICROBIOLOGICAL treatment system may be operating • there is no absolute certainty MONITORING OBJECTIVE within required parameters but this disinfection is 100 per cent is not a guarantee that quality can be Microbiological monitoring under the effective; and maintained to the farthest points of risk management approach is used the distribution system at all times. • human error may result in sample for operational purposes and as a fi nal Occasionally unsatisfactory water collection and laboratory mistakes. check to verify water quality. Tests of quality is recorded. microbial quality are a valuable adjunct The complete absence of E. coli to assessing source water protection, Whether from a supply breach detections in any water supply treatment, and the integrity of the or loss of adequate disinfection, system is an unreasonable expectation. barriers through to the consumer’s undesirable microorganisms in water The 2004 ADWG allows one failure tap. Monitoring of drinking water can be delivered to consumers. Ideally (E. coli detection) in 50 samples or quality should be regarded as the fi nal verification monitoring will identify that 98 per cent of samples contain check that the barriers and preventive such failures. no E. coli. measures implemented to protect LIMITATIONS OF MONITORING COMPLIANCE PERFORMANCE public health are working effectively. Performance can be regarded as Disinfection with chlorine provides a Power and Water’s Drinking Water satisfactory if over the preceding major barrier against microbiological Monitoring Program 2010-11 requires 12 months: hazards. The condition of this barrier that samples are representative of the can be determined by measurement quality of water supplied to consumers • at least the minimum number of of chlorine residuals however this is be collected and analysed for E. coli at programmed samples have been not an assessment of the effectiveness a minimum frequency determined by tested for E. coli; of the barrier. Microbial indicators can the population served by the supply. • samples tested are representative be used for verifying the effectiveness The results from this monitoring of the quality of water supplied to of disinfection, treatment and for provide an appraisal of the status and consumers; and effectiveness of the disinfection system assessing system cleanliness. • at least 98 per cent of programmed and in the extreme case whether this samples contain no E. coli (excludes MONITORING PROGRAM barrier has been compromised. The repeat or special purpose samples). confidence provided by this appraisal Verification or compliance diminishes as the number of samples Figure 5 shows for 2010-11 all major monitoring is performed routinely collected decrease and every time centres achieved the 98 per cent but less frequently than operational E. coli is detected. E. coli free target. monitoring. Where operational monitoring provides information to Although the objective of disinfection Tennant Creek was the only major maintain a treatment within defi ned is to eradicate microorganisms, it is centre to record E. coli detections but parameters, verification monitoring is unrealistic to expect results from a was able to comply with the target. performed deeper into the distribution monitoring program to show a water we value TEAMWORK

FIGURE 5 PERCENTAGE OF SAMPLES TAKENT AKEN IN MAJOR CENTRES IN WHICH NO E. COLI WERE DETECTED FROM 2007-12007-111

CENTRE 2007-08 2008-09 2009-10 2010-11

Alice Springs Darwin Katherine Tennant Creek Yulara 100%

99%

98%

97%

96%

95%

94%

93%

92%

91%

90%

Figure 6 presents results for all the minor centres in the Northern Territory 2010-11. E. coli was detected in Cox Peninsula, Elliott and Newcastle Waters water supplies. Elliott and Newcastle Waters failed to meet the 98 per cent E. coli free target.

FIGURE 6 PERCENTAGE OF SAMPLES TAKENT AKEN IN MINOR CENTRES IN WHICH NO E. COLI WERE DETECTED FROM 2007-12007-111

CENTRE 2007-08 2008 -09 2009-10 2010-11 100%

99%

98%

97%

96%

95%

94%

93%

92%

Tree i Waters Elliott T y Batchelor Borroloola Peninsula Larrimah Dal Mataranka Pine Creek Gunn Point Adelaide River Cox Kings Canyon Timber Creek Newcastle Waters power and water corporation DRINKING WATERW ATER QUALITYQUALITY 27 ANNUAL REPORREPORTT 2011

MONITORING PERFORMANCE throughout the entire supply, not less of thermophilic amoeba indicates than 0.5 mg/L. conditions in the water supply are The Power and Water’s Drinking conducive for the growth of N. fowleri Water Monitoring Program 2010-11 The effectiveness of chlorine to control and further investigation or remedial scheduled 1448 drinking water samples the growth of N. fowleri is better action may be warranted. Naegleria to be collected for bacteriological understood when comparisons can spp other than N. fowleri were detected assessment from 19 centres across be made between non-chlorinated in the Darwin, Gunn Point and Tennant the Northern Territory. The collection (source) waters and chlorinated Creek distribution systems, and Darwin and assessment of all programmed (distribution system) water. For the groundwater. Naegleria spp were not samples was not achieved. Bad 2010-11 period a total of 563 routine detected in surface waters. weather, communication failure and samples were collected from water logistical issues contributed to only supplies across the Territory. The Special investigations during sediment 98.3 per cent of these samples being program included samples from source removal from six tanks in the Darwin collected. Some centres were more waters and distribution systems. distribution system found N. fowleri successful than others. Detail of the Special investigations were instigated present in the sediment of four tanks. performance of individual centres is during tank cleaning in Darwin. These results are reported in table 4. presented in Appendices tables A1 Samples of sediment and water were In response the cleaning of tanks and A2. (refer pages 36-37) collected from several storage tanks in was completed, dosed to 1 mg/L the Darwin distribution system. free chlorine and held off-line until laboratory results confi rmed them NAEGLERIA FOWLERI Table 4 show the results from 2010-11 to be clear of N. fowleri. Long term N. fowleri N. fowleri monitoring program. Since the initial detection of strategies to control N. fowleri in tanks in the Darwin distribution system N. fowleri was detected only in the include an increase in the frequency of in 2005, Power and Water have Darwin distribution system. N. fowleri tank cleaning to minimise sediment undertaken extensive monitoring was detected on four occasions at the accumulation. of water supplies and implemented Manton Dam Park Tap sampling point. procedures to control this amoeba. The Manton Dam Park Tap is the At the time the free chlorine residual drinking water supply for visitors to Providing a chlorine residual was low. Remedial action included Manton Dam. As this site is at the end mains flushing and re-establishment throughout the distribution system of the distribution system and is used can provide protection against of an effective free chlorine residual. infrequently, the free chlorine residual Follow-up investigations did not fi nd contamination and limit the regrowth is often inadequate. As a consequence N. fowleri N. fowleri present at that location. of . Free chlorine at there have been several detections 0.5 mg/L or higher will control All other distribution systems and of N. fowleri over the past few years. N. fowleri, provided the disinfectant sources monitored during the 2010-11 Power and Water has improved the persists at that concentration period were free of N. fowleri. free chlorine residual at this site by throughout the water supply system. installing an automatic irrigation The 2004 ADWG action level focuses Power and Water now require all system which routinely draws water on N. fowleri but any detection continuously chlorinated water through the pipeline displacing of any thermophilic amoeba is supplies to maintain a minimum chlorine depleted water. free chlorine residual, considered signifi cant. The detection value value we *Amoeba detection refers*Amoeba detection to samplesfoundto contain amoeba. No reference insamples. the numberofamoeba detected to ismade TABLETABLE 4: THERMOPHYLIC AMOEBA DETECTIONSDETECTIONS,, MONITORED SUPPLIES AND INVESTIGATION 202010-111 0-1 1 TEAMWORK

POSITIVE SAMPLES Centre Routine Samples Amoebae* Amoebae* Acanthamoeba Willaertia Naegleria Naegleria spp Naegleria Naegleria Naegleria Monitoring collected Total Total (solids) group III HartmHartmannellaannella magna spp Total Total (solids) australiensis lolovaniensisvaniensis fowleri Alice Springs 3 0 N/A 0 0 0 0 N/A 0 0 0 Distribution Cox Peninsula 8 0 N/A 0 0 0 0 N/A 0 0 0 Surface Water Cox Peninsula 51 3 N/A 0 3 0 0 N/A 0 0 0 Distribution Darwin 208 54 N/A 1 54 0 11 N/A 1 10 4 Distribution Darwin Source 10 2 N/A 0 1 0 1 N/A 0 1 0 Bores Darwin Source 12 1 N/A 0 1 0 0 N/A 0 0 0 Reservoir Gunn Point 22 1 N/A 0 1 0 1 N/A 0 1 0 Distribution Katherine 28 0 N/A 0 0 0 0 N/A 0 0 0 Distribution Pine Creek 2 0 N/A 0 0 0 0 N/A 0 0 0 Source Dam Pine Creek 6 0 N/A 0 0 0 0 N/A 0 0 0 Distribution Tennant Creek 205 28 N/A 4 10 0 15 N/A 0 15 0 Distribution Yulara 6 0 N/A 0 0 0 0 N/A 0 0 0 Distribution Yulara Source 2 0 N/A 0 0 0 0 N/A 0 0 0 Bores TOTAL SAMPLES 563 InInvestigationvestigation Monitoring Darwin Tank 8 0 7 1 4 3 3 2 0 1 5 Sediments Darwin Tank 7 3 N/A 1 2 1 0 N/A 0 0 0 and Hydrant power and water corporation DRINKING WATERW ATER QUALITYQUALITY 29 ANNUAL REPORREPORTT 2011

BURKHOLDERIA PSEUDOMALLEI

Burkholderia pseudomallei is the agent responsible for melioidosis and despite being ubiquitous throughout the tropics its ecology is poorly understood. Epidemiological evidence has established melioidosis can be contracted by exposure to contaminated soil or water where the bacteria enter via skin cuts and lesions. Human infections have a high mortality rate. The latent phase between infection and disease can be extremely long, up to months or even years, and relapse is quite common. Other routes of transmission, specifically gastrointestinal, have not been confirmed. Despite its apparent ubiquity there have been few waterborne outbreaks. Power and Water’s Drinking Water Monitoring Program 2010-11 includes B. pseudomallei as an investigative and research activity. Initially monitoring sites and frequency were in response to the identifi cation of clusters of melioidosis cases. During 2010-11 Power and Water worked closely with Menzies School of Health Research (MSHR) to identify water supplies likely to be at risk of colonisation by B. pseudomallei. Recent research has confi rmed an association between B. pseudomallei ABOVE > WWATERATER SAMPLE COLLECTION AT DDARWINAR WIN RIVER RESERVOIR OFF-TAKE TOWERTO WER and bore water which has low salinity, high iron levels, low pH and low hardness. This finding aids in particularly the aerator and reactivator, CHEMICAL AND PHYSICAL identifying water supplies at risk of are uncovered, unsealed and therefore RESULTS SUMMARY contamination with this pathogenic susceptible to dust. Samples were Health-related water quality bacterium. Borroloola source waters collected from points within the parameters are reported as the have pH values as low as 5.1, iron Katherine water treatment plant and 95th percentile. If data is limited levels as high as 12.2 mg/L, very soft distribution system. B. pseudomallei values are reported as the maximum water with hardness measured as was detected in the treatment plant value. Aesthetic parameters are low as 4.5 mg/L (CaCO3) and low filter sand and treatment plant clarifi er reported as an average as specifi ed salinity EC = 50μS/cm (2010-11 sludge but not in water leaving the in the 2004 ADWG. values) and was therefore considered treatment plant. vulnerable to B. pseudomallei Details of the health and aesthetic As the Tennant Creek water supply colonization. Water samples collected parameters for each major and minor is a non-chlorinated supply it lacks from the Borroloola water supply centre are shown in the Appendices a crucial barrier against bacterial were negative for B. pseudomallei. tables A3 and A4. (refer pages 38-41) contamination. Power and Water has Clinical literature documents infection continuously monitored this supply for RADIOLOGICAL by the inhalation of contaminated dust the past five years. As in previous years suggesting water supplies open to the B. pseudomallei was not detected in All water supplies are investigated to environment are at risk. Components the Tennant Creek water supply in the gain an initial measure of gross alpha of the Katherine water treatment plant, 2010-11 monitoring period. and gross beta activity concentrations. we value TEAMWORK

The 2004 ADWG recommend further To comply with 2004 ADWG Kings Canyon’s water supply has higher radiological measurements be radiological data used in the levels of radionuclides than other undertaken to ascertain the total calculation of the total annual Northern Territory water supplies and annual radiation dose if the gross radiation dose must be no more than is intensely monitored. Eighty one activities are higher than 0.5 Bq/L. two years outside the reporting period samples were collected from the Kings The 2004 ADWG recommend the for ground water supplies and no more Canyon supply during 2010-11. Four of total annual radiation dose not than five years for surface water. these samples exceeded the 1.0 mSv/ exceed 1 mSv/year. year limit with the highest value, 1.24 ANNUAL ASSESSMENT mSv/year, recorded at the ground tank To precisely calculate the annual outlet. The annual radiological dose radiological dose, all radioactive species When a water supply passes both for the two year monitoring period is in the water supply must be identifi ed the gross alpha and potassium-40 0.99 mSv/year (95th percentile). and their activity concentrations corrected gross beta screening determined. Generally radium-226 assessment or, the estimated annual The annual radiological dose for and radium-228 are the major dose is below 0.5 mSv/year, sampling Borroloola is calculated from a small radionuclides contributing to the can be less frequent – every two years data set. The gross alpha level of four gross alpha and beta values. When for groundwater supplies, every fi ve samples was greater than 0.5 Bq/L and radium-226 and radium-228 do not years for surface water supplies. failed the screening level. The annual account for all gross alpha and beta All water supplies included in this radiological dose for the Borroloola values other radionuclides present report draw some, if not all water, water supply is reported as 0.37 mSv/ must be identified and their levels from ground water sources. As year the maximum value recorded. determined. radiological data from groundwater Results for the radiological assessment The likely worst case leading to is valid for two years, supplies of all supplies are shown in the the highest exposure is where the monitored during 2009-10 may not Appendices tables A3 and A4. (refer gross alpha and gross beta activities have been required to be monitored pages 38-41) are due entirely to radium-226 during 2010-11. The radiological results (an alpha emitter) and radium-228 presented in this report therefore TRIHALOMETHANES cover the period 2009-11. (a beta emitter). THMs in Power and Water supplies If the analysis fails to include all Water from 12 minor centres and were initially measured in 2002-03 to radionuclides the total annual four major centres complied with establish a baseline data set. Values radiation dose is calculated by treating the 2004 ADWG screening level, with ranged from less than 0.004 mg/L in the gross alpha value as if it were due radioactivity levels below 0.5 Bq/L. All Alice Springs to less than 0.08 mg/L entirely to radium-226 and the K40 19 centres passed annual radiological in Darwin. These concentrations corrected gross beta value as if it assessment with no water supply were well below the 2004 ADWG were due entirely to radium-228. exceeding the annual guideline limit level of 0.25 mg/L. of 1.0 mSv/year. As described previously, this treatment During the 2010-11 monitoring period of the assessment calculates the Water for the Borroloola town camp all water supplies except Tennant Creek maximum possible exposure. Garawa is drawn from ground water. and Ti Tree were assessed for THMs. This source was not assessed for The concentration of THMs for these This approach derives its validity radiological characteristics during water supplies ranged from <0.004 from the knowledge that radium-226 the two year period leading up to to 0.070 mg/L. Tennant Creek is not and radium-228 are the most this report. consequential radionuclides present included in this assessment as it is not in water and on a concentration- Eleven bores supplying Alice Springs a continuously chlorinated supply. passed annual radiological assessment based comparison, contribute more Long term THM levels (2006-2011) at the screening level. to the annual dosage than any other are shown in the Appendices tables radionuclide. The annual radiation Four bores exceeded either 0.5 Bq/L A3 and A4. (refer pages 38-41) dose calculated by this method is a for gross alpha or 0.5 Bq/L for K-40 THMs in all water supplies remain at conservative solution and produces a corrected gross beta. No bore exceeded levels similar to those measured in total annual radiation dose estimate the annual guideline limit of 1.0 mSv/ previous years and appear to be stable. in excess of the true value. year. The annual radiological dose An estimation of the total annual is reported as 0.43 mSv/year, the The low levels of THMs measured in radiation dose cannot be made maximum value measured in all of NT water supplies is due to the low without values for gross alpha and the 15 bores. level of total organic carbons (TOC), the gross beta activities. precursors of THMs, in these waters. The highest levels of THMs power and water corporation DRINKING WATERW ATER QUALITYQUALITY 31 ANNUAL REPORREPORTT 2011

ABOVE > MEASURINGMEASUR I NG CHLORINE RESIDUALS WWITH ITH A PORPORTABLE TABLE CHLORINE METER are in Darwin, Katherine and Pine Creek been found to contain pesticides or catchment. Dicamba is moderately supplies all of which use surface water. where local pesticide usage suggests a persistent in soil and breaks down to water supply may be at risk. very simple substances such as carbon HERBICIDES AND PESTICIDES dioxide and water. Its reported half-life Good management of surface in soil ranges from one to six weeks. The 2004 ADWG health values for water sources and bores reduce the This herbicide is applied two to three pesticides are very conservative and risk of drinking water becoming times a year as part of the mimosa include a range of safety factors. contaminated with pesticides. control program. The values are derived from the Bores are required to be constructed acceptable daily intake (ADI) and set to standards that guarantee bore Although monitored for several at about 10 per cent of the ADI for an head integrity and prevent surface years, pesticides in the Northern adult weight of 70 kg for a daily water water (potentially containing Territory water supplies have not consumption of two litres. Although pesticides) from entering the bore. been detected despite limited use in guideline values have been provided Surface waters (dams and rivers) are some areas. In consideration of these for a large number of pesticides, most managed to strictly control pesticide results, pesticide monitoring during are unlikely to be present in Australian use in their catchments. 2010-11 was restricted to Darwin and Katherine water supplies. These drinking water supplies. Occasionally, weed problems in supplies are considered potentially reservoirs and catchments can only The pesticide monitoring program vulnerable to pesticide contamination be managed effectively through focuses on 43 commonly used due to agricultural activities close the use of herbicides. Dicamba pesticides including organochlorine, to production bores and surface (Banvel, 3,6-dichloro-2-methoxybenzoic organophosphate and triazine water sources. Results for all samples acid) is a moderate to low toxicity pesticides, insecticides and acidic collected from these supplies were herbicide used to control weeds and herbicides. Monitoring is undertaken below the level of detection. on water supplies that have previously mimosa in the Darwin River Reservoir we value TEAMWORK

CUSTOMER SATISFACTION WATER QUALITY CUSTOMER COMPLAINTS

Appearance, taste and odour are Power and Water records all water Table 5 shows the total number of monitored as they are generally the quality complaints made by customers water quality specifi c complaints characteristics by which customers and reports them to the National received during 2010-11. judge water quality. Water Commission for publication, as do other Australian water utilities. TTABLEABLE 5: WATER W ATER QUALITQUALITY Y COMPLCOMPLAINTS AINTS 2006-202006-201111

Total Number of Complaints Centre Properties 2006-07 2007-08 2008-09 2009-10 2010-11 (2010-11) Adelaide River 102A DNA DNA 1 1 3 Alice Springs 11510B 5 1 4 5 22 Darwin 50694B 147 373 355 123 134 Katherine 2163A 2 DNA DNA 1 48 Tennant Creek 1237A DNA DNA DNA DNA 0 Total 65706 154 374 360 130 207 Complaints per 1000 2.44 6.13 5.77 2.44 3.15 properties (all NT)

A Properties based on number of meters B As reported to NWC in 2010-11 NPR DNA Data not available The pattern of complaints made due to stratifi cation, oxygen consumed Dry Season, as fl ows in the distribution about the Darwin water supply is in the lower layers is not replenished system increase, the settled iron and largely governed by changes in water from the surface resulting in oxygen manganese are mobilised by the quality associated with the seasonal depletion at the bottom of the reservoir. higher velocity water and become the variation in reservoir water quality cause of further customer complaints. The decomposition of organic material and customer demand. under anaerobic conditions lowers The levels of iron and manganese in the As with many water supply reservoirs, the pH and encourages production drinking water do not constitute a health Darwin River Reservoir is subject to of hydrogen sulphide. This process risk due to the relatively short duration stratifi cation. Stratifi cation is the reduces iron and manganese in the of the discoloured water events. development of distinct layers of water sediments to soluble forms. The frequency of drinking water of different temperature or density at Once the reservoir has stratifi ed, a complaints for the Darwin water supply various depths in a water body and large amount of energy is required during 2010-11 is shown in Figure 7. the subsequent restriction of mixing to disrupt the layered structure. between these layers. Stratifi cation Power and Water works to minimise develops when the upper layers of the De-stratifi cation occurs with a decrease the frequency and the magnitude of reservoir are heated by solar radiation in surface temperature, in-fl ow and these events primarily through a mains faster than the heat can disperse into wind-induced mixing processes that flushing program in major centres the lower depths of the reservoir. The cause the layers to mix and bring low where customers frequently report generated difference in the surface quality anoxic water from the bottom discoloured water. Mains are fl ushed and bottom densities limit circulation of the reservoir to the surface where before anticipated increased demands between these layers and can lead it is drawn into the supply. associated with seasonal changes. If to these layers having signifi cantly a customer reports discoloured water, Soluble iron and manganese entering different water qualities. Power and Water fl ushes the mains the distribution system can be supplying the customer’s residence. Atmospheric oxygen is absorbed by oxidized and precipitate out of solution water at the interface between air creating discoloured water resulting In addition to this, water quality is and water. Algal photosynthesis near in customer dissatisfaction and monitored at a number of locations the surface also supplies oxygen to complaints. During the Wet Season, as in the Darwin water supply to gauge the water. Oxygen at the bottom water demand drops and flow rates are the extent of discoloured water of a reservoir is consumed by the reduced, oxidised iron and manganese and determine when routine fl ushing decomposition of organic material. can settle out in the distribution is required. As water circulation is restricted system. At the beginning of the next power and water corporation DRINKING WATERW ATER QUALITYQUALITY 3333 ANNUAL REPORREPORTT 2011

FIGURE 7 NUMBER OF MONTHLMONTHLYY DRINKING WWATER ATER CUSTOMER COMPLAINTS FOR DDARWINAR WIN 202010-11 1 0-1 1 Number of Complaints Number of

April 2011 May 2011 June 2011 August 2010 March 2011 October 2010 January 2011 February 2011 September 2010 November 2010December 2010

Month

Customers have also complained about by-products when water is disinfected is carried out and, when necessary, cloudy water, floating particles, odour, with chlorine. water samples are taken and analysed. taste and high chlorine levels. Sometimes a customer will report As a response to the detection of High chlorine levels manifest cloudy or milky water. This is generally N. fowleri in some NT water supplies, themselves as chlorinous taste and due to the presence of dissolved air free chlorine residuals are now odour complaints. in the water. Milkiness or cloudiness maintained at a minimum of 0.5 mg/L. most commonly occurs after water This level of chlorine is objectionable to Figure 8 shows a breakdown of mains repairs and repressurising of some customers who have complained customer complaints for 2010-11. water mains causes trapped air to about the chlorinous taste. Taste and odour complaints often be dissolved. When a tap is turned While Darwin water quality complaints relate to varying chlorine levels due to on, minute air bubbles are released remained the same as last year a changing water demand. The chlorine causing the water to appear milky. marked increase from Alice Springs residual in the reticulation network When left to stand, this cloudy water and Katherine were received. All is regularly monitored and adjusted will clear rapidly. Other causes of complaints received in Katherine as required. Online water quality cloudy water are tap aerators and related to discoloured water on two monitoring units have been installed hot water systems. distinct occasions each event lasting in most centres to improve monitoring Occasionally harmless white algae approximately one week. One event across the entire network. can be observed in the Darwin water has been attributed to a sudden rise Objectionable tastes and odours can supply. These algae grow naturally in chlorine concentration and the also result from compounds produced in Darwin River Reservoir and their second to replacement of valves by certain types of algae, cyanobacteria original green colour is lost during requiring excavation and cutting of (blue-green algae), bacteria and the disinfection process. major pipe work. Complaints received sometimes protozoa. A number of in Alice Springs related to discoloured If there is doubt as to the cause of a organic compounds causing tastes and cloudy water and attributable to water quality problem an investigation and odours can be produced as mains repairs. we value TEAMWORK

FIGURE 8 BREAKDOWN OF CUSTOMER COMPLAINTS FOR DARWINDAR WIN 202010-11 10 -1 1 SHOWING MAJOR WWATERATER QUALITYQUALIT Y ISSUES

1% 1%

3%

6%

Discoloured

11% Taste and odour

Cloudy

Other

77% Blue green

Alleged illness power and water corporation DRINKING WATERWATER QUALITQUALITYY 35 ANNUAL REPORREPORTT 2011

RECORDED EMERGENCIES/ INCIDENTS

No water quality emergencies were recorded in 2010-11. Continual investment in the upgrading of facilities and securing of systems has reduced risks and the potential for contamination or failure. In the 2010-11 year there were fi ve incidents in which E. coli was detected in water supplies: Response to these incidents included manual chlorination of tanks, fl ushing of mains and re-sampling of the water supply as agreed with DoH. Water supplies were tested immediately following remedial action and all supples were negative for the presence of E. coli.

TABLE 6 E. COLICOLI INCIDENTS 202010-111 0-1 1

Samples with Number of E.coliE. coli Water Supply Centre E.coliE. coli detected Date of Detection in sample Elliott1 2 samples 07/03/2011 3 and 6 Newcastle Waters 1 sample 09/05/2011 3 Tennant Creek 1 sample 17/01/2011 1 Tennant Creek 1 sample 28/03/2011 1

1 Single incident we value COMMITMENT

APPENDICES

T:BTABLEABLE A1: A1 BACTERIOLOGICAL ACTERIOLOGICAL MONITORING IN MAJOR CENTRES 202010-111 0-1 1

Samples Total NoNo. .ofof Total NoNo. .ofof Total Passing Parameter Samples Samples Exceedences Reporting Centre (mpn/100 mL) Target Level Required Collected* (No.) LeLevelvel (%) Alice Springs E. coli <1 in 98% of samples 104 104 0 100.0 104 104 0 100.0 Total Coliforms <10 in 95% of samples Darwin E. coli <1 in 98% of samples 468 465 0 100.0 468 465 0 100.0 Total Coliforms <10 in 95% of samples Katherine E. coli <1 in 98% of samples 104 104 0 100.0 104 104 0 100.0 Total Coliforms <10 in 95% of samples Tennant E. coli <1 in 98% of samples 104 104 2 98.1 Creek Total Coliforms <10 in 95% of samples 104 104 18 82.7 Yulara E. coli <1 in 98% of samples 52 52 0 100.0 52 52 0 100.0 Total Coliforms <10 in 95% of samples

*Numbers in bold indicate samples collected are less than the number specified in the monitoring program. power and water corporation DRINKING WATERWATER QUALITQUALITYY 37 ANNUAL REPORREPORTT 2011

TBTABLEABLE A2: BACTERIOLOGICAL ACTERIOLOGICAL MONITORING IN MINOR CENTRES 202010-111 0-1 1

Samples Total NoNo. .ofof Total NoNo. .ofof Total Passing Parameter Samples Samples Exceedances Reporting Centre (mpn/100 mL) Target Level Required Collected (No.) LeLevelvel (%) Adelaide River E. coli <1 in 98% of samples 24 24 0 100.0 24 24 0 100.0 Total Coliforms <10 in 95% of samples Batchelor E. coli <1 in 98% of samples 52 52 0 100.0 52 52 2 96.1 Total Coliforms <10 in 95% of samples Borroloola E. coli <1 in 98% of samples 24 24 0 100.0 24 24 0 100.0 Total Coliforms <10 in 95% of samples Cox Peninsula E. coli <1 in 98% of samples 52 51 1 98.0 Total Coliforms <10 in 95% of samples 52 51 1 98.0 Daly Waters E. coli <1 in 98% of samples 24 24 0 100.0 Total Coliforms <10 in 95% of samples 24 24 2 91.7 Elliott E. coli <1 in 98% of samples 104 91 2 97.8 Total Coliforms <10 in 95% of samples 104 91 2 97.8 Garawa1 E. coli <1 in 98% of samples 24 18 0 100.0 Total Coliforms <10 in 95% of samples 24 18 0 100.0 Gunn Point E. coli <1 in 98% of samples 12 22 0 100.0 Total Coliforms <10 in 95% of samples 12 22 0 100.0 Kings Canyon E. coli <1 in 98% of samples 104 100 0 100.0 Total Coliforms <10 in 95% of samples 104 100 0 100.0 Larrimah E. coli <1 in 98% of samples 24 24 0 100.0 Total Coliforms <10 in 95% of samples 24 24 0 100.0 Mataranka E. coli <1 in 98% of samples 24 24 0 100.0 Total Coliforms <10 in 95% of samples 24 24 1 95.8 Newcastle E. coli <1 in 98% of samples 24 23 1 95.7 Waters Total Coliforms <10 in 95% of samples 24 23 0 100.0 Pine Creek E. coli <1 in 98% of samples 24 24 0 100.0 Total Coliforms <10 in 95% of samples 24 24 0 100.0 Ti Tree E. coli <1 in 98% of samples 24 20 0 100.0 Total Coliforms <10 in 95% of samples 24 20 0 100.0 Timber Creek E. coli <1 in 98% of samples 24 24 0 100.0 24 24 1 95.8 Total Coliforms <10 in 95% of samples

1 Although Garawa is not a Power and Water minor centre it is included in this table for convenience. we value COMMITMENT

TTABLEABLE A3: HEALTH, AESTHETIC AND OTHEROP THER PARAMETERS ARAMETERS IN MAJOR CENTRES 202010-111 0-1 1

Guideline Alice Parameter/Centre Value1 Units Springs Darwin Katherine Tennant Creek Yulara HEALTH PARAMETERS - 95TH PERCENTILE VALUES Antimony 0.003 mg/L 0.0002 0.0002 0.0002 0.0002 0.0002 Arsenic 0.007 mg/L 0.0005 0.0005 0.0007 0.0026 0.0006 Barium 0.7 mg/L 0.10 0.05 0.05 0.05 0.06 Boron 4 mg/L 0.13 0.02 0.02 0.52 0.84 Cadmium 0.002 mg/L 0.0002 0.0002 0.0002 0.0009 0.0008 Chlorine (free) 5 mg/L 1.11 1.71 0.84 N/A 0.66 Chromium 0.05 mg/L 0.005 0.005 0.005 0.006 0.006 Copper 2 mg/L 0.16 0.33 0.08 0.08 0.15 Fluoride 1.5 mg/L 0.5 0.8 0.5 1.6 0.1 Iodide 0.1 mg/L 0.09 0.02 0.01 0.36 0.05 Lead 0.01 mg/L 0.005 0.002 0.002 0.001 0.002 Manganese 0.5 mg/L 0.005 0.047 0.014 0.006 0.006 Mercury 0.001 mg/L 0.0001 0.0001 0.0001 0.0001 0.0001 Molybdenum 0.05 mg/L 0.005 0.005 0.005 0.006 0.006 Nickel 0.02 mg/L 0.005 0.002 0.002 0.002 0.003 Nitrate 50 mg/L 8 3 1 49 52 Radiological4 1.0 mSv/yr 0.43 PASS PASS PASS PASS Selenium 0.01 mg/L 0.002 0.001 0.001 0.005 0.001 Silver 0.1 mg/L 0.01 0.01 0.01 0.01 0.01 Sulfate 500 mg/L 62 12 12 59 438 THMs5 0.25 mg/L <0.004 0.101 0.065 <0.004 0.014 Uranium 0.02 mg/L 0.00901 0.00009 0.00022 0.00875 0.00005 AESTHETIC PARAMETERS - MEAN VALUES Aluminium 0.2 mg/L 0.02 0.02 0.04 <0.02 <0.02 Chloride 250 mg/L 79 9 8 101 134 Chlorine (free) 0.6 mg/L 0.76 0.62 0.67 N/A 0.52 Copper 1 mg/L 0.05 0.06 0.02 0.02 0.06 mg/L Hardness 200 210 50 166 170 25 (CaCO3) Iron 0.3 mg/L 0.04 0.09 0.28 0.06 0.04 Manganese 0.1 mg/L 0.005 0.023 0.006 <0.005 <0.005 pH 6.5-8.5 pH 8.0 7.6 7.8 7.8 7.7 units Sodium 180 mg/L 79 3 5 125 59 Sulfate 250 mg/L 51 3 5 47 106 TDS 800 mg/L 443 64 187 609 224 Zinc 3 mg/L 0.02 0.01 0.01 0.01 0.06 OTHER PARAMETERS - MEAN VALUES Alkalinity mg/L 237 49 156 278 35 Beryllium mg/L 0.001 0.001 0.001 <0.001 <0.001 Bromide mg/L 0.28 0.02 0.02 0.73 0.67 Calcium mg/L 46 10 38 26 20 Electrical uS/cm 803 109 318 971 604 conductivity Magnesium mg/L 24 6 16 25 8 Potassium mg/L 5.9 0.4 0.8 29.3 9.6 Silica mg/L 18 13 18 74 11 Tin mg/L 0.01 0.01 0.01 <0.01 <0.01 power and water corporation DRINKING WATERW ATER QUALITYQUALITY 39 ANNUAL REPORREPORTT 2011

LEGEND (TABLE A3 & A4)

Radiological Results are reported as ‘Pass’ if screening levels of gross alpha and gross beta (K corrected) are less than 0.5 Bq/L. Water supplies passing the screening level do not require an annual dosage assessment. Where assessment is required data used is not more than two years older than the starting date of the reporting period for bores and five years for surface water. Annual dosage is reported as 95th percentile for large data sets and maximum value for small data sets. Data covers the period 2006-11. THMs Reported as the maximum values as data sets are small. Health Assessments are reported as the 95th percentile. Data covers the period 2006-11. Exceedances are shown bold parameters Aesthetic Assessments are reported as the mean. Data covers the period 2006-11. Exceedances are shown bold and Other parameters N/A Not applicable * No guideline value applicable mSv/yr millisieverts per year μS/cm microsiemens per centimetre mg/L milligrams per litre DNA Data not available - supplies for which there is insufficient data, incomplete data or where the only data available is outdated are reported as data not available (DNA). < All values reported preceded with “<” indicate the value is below the level of detection of the analytical method. 1 2004 ADWG value for health and aesthetic parameters. TDS value set by DoH. we value COMMITMENT

TTABLEABLE A4: HEALTH, AESTHETIC AND OTHEROP THER PARAMETERS ARAMETERS IN MINOR CENTRES 202010-111 0-1 1 Guideline Adelaide Cox Daly Parameter/Centre Value1 Units River Batchelor Borroloola Peninsula Waters Elliott HEALTH PARAMETERS - 95TH PERCENTILE VALUES Antimony 0.003 mg/L 0.0013 0.0002 0.0002 0.0002 0.0004 0.0002 Arsenic 0.007 mg/L 0.0057 0.0006 0.0006 0.0005 0.0012 0.0005 Barium 0.7 mg/L 0.05 0.06 0.06 0.05 0.08 0.17 Boron 4 mg/L 0.02 0.02 0.05 0.02 0.44 0.34 Cadmium 0.002 mg/L 0.0002 0.0002 0.0002 0.0002 0.0003 0.0002 Chlorine (free) 5 mg/L 1.88 1.16 0.96 1.41 1.28 1.67 Chromium 0.05 mg/L 0.005 0.006 0.006 0.005 0.006 0.005 Copper 2 mg/L 0.48 0.17 0.83 0.12 0.27 0.02 Fluoride 1.5 mg/L 0.4 0.2 0.1 0.1 0.5 0.8 Iodide 0.1 mg/L 0.01 0.01 0.02 0.01 0.25 0.12 Lead 0.01 mg/L 0.002 0.001 0.004 0.003 0.003 0.003 Manganese 0.5 mg/L 0.246 0.006 0.033 0.008 0.153 0.005 Mercury 0.001 mg/L 0.0001 0.0001 0.0001 0.0001 0.0002 0.0001 Molybdenum 0.05 mg/L 0.005 0.006 0.006 0.005 0.006 0.005 Nickel 0.02 mg/L 0.002 0.002 0.004 0.003 0.005 0.004 Nitrate 50 mg/L 7 2 1 8 12 41 Radiological4 1.0 mSv/yr PASS PASS 0.37 PASS PASS PASS Selenium 0.01 mg/L 0.001 0.001 0.001 0.001 0.007 0.003 Silver 0.1 mg/L 0.01 0.01 0.01 0.01 0.01 0.01 Sulfate 500 mg/L 3 2 3 28 234 852 THMs5 0.25 mg/L 0.007 <0.004 0.013 <0.004 0.019 <0.004 Uranium 0.02 mg/L 0.00006 0.00042 0.00024 0.00003 0.00784 0.00623 AESTHETIC PARAMETERS - MEAN VALUES Aluminium 0.2 mg/L 0.02 0.02 0.02 0.02 0.02 0.02 Chloride 250 mg/L 28 11 11 10 358 153 Chlorine (free) 0.6 mg/L 1.12 0.70 0.77 0.83 0.87 1.12 Copper 1 mg/L 0.10 0.04 0.15 0.04 0.05 0.01 mg/L Hardness 200 100 191 22 8 526 396 (CaCO3) Iron 0.3 mg/L 0.74 0.06 0.16 0.03 0.21 0.10 Manganese 0.1 mg/L 0.118 0.004 0.012 0.005 0.032 0.005 pH 6.5-8.5 pH units 7.1 7.6 6.5 6.7 7.5 8.0 Sodium 180 mg/L 26 5 6 7 215 95 Sulfate 250 mg/L 2 1 1 12 193 245 TDS 800 mg/L 188 224 53 51 1310 782 Zinc 3 mg/L 0.03 0.02 0.04 0.05 0.02 0.01 OTHER PARAMETERS - MEAN VALUES Alkalinity mg/L 110 214 37 20 433 359 Beryllium mg/L 0.001 0.001 0.001 0.001 0.001 0.001 Bromide mg/L 0.06 0.01 0.02 0.01 1.74 0.76 Calcium mg/L 17 31 7 3 127 88 Electrical uS/cm 323 408 80 54 2107 1300 conductivity Magnesium mg/L 14 34 1 0 61 44 Potassium mg/L 1.0 0.3 1.1 1.0 24.9 22.1 Silica mg/L 35 30 14 22 38 57 Tin mg/L 0.01 0.01 0.01 0.01 0.01 0.01 2 Although Garawa is not a Power and Water minor centre it is included in this table for convenience. power and water corporation DRINKING WATERWATER QUALITQUALITYY 41 ANNUAL REPORREPORTT 2011 gggg

Kings Newcastle Timber Garawa2 Gunn Point CaCanyonnyon Larrimah Mataranka Waters Pine Creek TiTreeTi Tree Creek

DNA <0.0002 0.0005 0.0005 0.0005 0.0002 0.0002 0.0002 0.0002 DNA <0.001 0.0044 0.0005 0.0005 0.0005 0.0077 0.0010 0.00100.0016 DNA <0.3 0.06 0.05 0.05 0.28 0.05 0.10 1.851.83 DNA <0.02 0.36 0.23 0.26 0.28 0.02 0.37 0.13 DNA <0.0002 0.0003 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.85 1.42 0.78 0.76 0.82 1.16 1.19 1.25 0.66 DNA <0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.006 DNA <0.02 0.49 0.06 0.08 0.03 0.07 0.01 0.040.36 DNA 0.4 0.5 0.2 0.4 0.9 0.6 0.8 1.4 DNA <0.01 0.43 0.10 0.09 0.09 0.09 0.17 0.03 DNA <0.002 0.011 0.001 0.002 0.001 0.003 0.001 0.0020.019 DNA 0.045 0.006 0.005 0.008 0.005 0.179 0.005 0.1930.190 DNA <0.0001 0.0004 0.0002 0.0002 0.0001 0.0001 0.0001 0.0001 DNA <0.005 0.006 0.005 0.005 0.005 0.005 0.005 0.006 DNA <0.004 0.013 0.004 0.003 0.007 0.002 0.002 0.007 DNA <1 10 4 3 10 1 58 1 DNA PASS 0.99 PASS PASS PASS PASS PASS PASS DNA <0.001 0.009 0.002 0.003 0.001 0.001 0.002 0.001 DNA <0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 DNA 4 200 100 143 144 73 102 6 DNA 0.016 0.005 0.005 0.011 <0.004 0.029 0.005 0.007 DNA 0.00109 0.00270 0.00262 0.00334 0.00524 0.00022 0.00942 0.00219

DNA <0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 DNA 13 261 203 174 49 13 71 30 0.61 0.85 0.54 0.60 0.64 0.68 0.76 0.99 0.48 DNA <0.02 0.09 0.02 0.03 0.02 0.03 0.02 0.020.05 DNA 166 365 487 470 293 121 202 395

DNA 0.07 0.21 0.06 0.17 0.05 0.14 0.04 0.060.08 DNA 0.045 0.004 0.005 0.005 0.005 0.058 0.005 0.0230.022 DNA 8.7 6.9 7.6 7.7 7.9 7.1 8.0 7.3 DNA 11 115 114 130 53 30 66 22 DNA 3 177 100 119 48 27 43 5 DNA 184 809 914 862 539 216 514 454 DNA 0.18 0.06 0.04 0.03 0.02 0.02 0.02 0.02

DNA 185 129 447 470 380 142 210 442 DNA <0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 DNA 0.01 1.39 0.97 0.81 0.17 0.05 0.40 0.13 DNA 23 71 119 114 67 20 45 61

DNA 370 1380 1549 1516 883 360 786 867

DNA 26 44 51 51 33 17 22 62 DNA 3.9 23.6 11.6 17.6 29.3 1.4 18.3 6.7 DNA 12 21 43 40 58 42 94 22 DNA <0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 we value COMMUNICATION

GLOSSARGLOSSARY Y OF ACRONYMS

ADI Acceptable Daily Intake ADWG Australian Drinking Water Guidelines (2004). Referred to in this report as “2004 ADWG” ANSI American National Standards Institute AS/NZS Australian/New Zealand Standards AWA Australian Water Association AWWA American Water Works Association CRC Cooperative Research Centre DCI Department of Construction and Infrastructure (from 4 December 2009) DHCS Department of Health and Community Services (until 1 July 2008) DNA Data not available DNRETAS Department of Natural Resources, Environment, The Arts and Sport DoH Department of Health DoR Department of Resources DRD Darwin River Dam EMS Electronic management system ESO Essential service operator FC/TC Free chlorine/Total chlorine ratio FIS Facilities Information System IBM International Business Machines IMS Information Management System ISO International Organization For Standardization ML mega litres MSHR Menzies School of Health Research N/A Not applicable NF Naegleria fowleri NHMRC National Health and Medical Research Council NPR National Performance Report NRMMC National Resources Management Council NT Northern Territory NWC National Water Commission OHS Occupational Health and Safety PAM Primary amoebic meningoencephalitis PI System Process information system for the management of real time data and events PWC Power and Water Corporation SAI Global Standards Australia International (Global) SCADA Supervisory control and data acquisition TDS Total dissolved solids THMS Trihalomethanes TOC Total organic carbons TRIM Power and Water’s electronic document management system UV Ultra violet WIMS Work information management system WIOA Water industry operators Association WQRA Water Quality Research Australia WSAA Water Services Association of Australia power and water corporation DRINKING WATERW ATER QUALITYQUALITY 43 ANNUAL REPORREPORTT 2011

UNITS OF STANDARDS MEASUREMENT AS/NZS ISO 14001:2004 AS/NZS 4801:2001 Bq/L Becquerel per litre Environmental management systems – Occupational health and Requirements with guidance for use safety management systems – μg/L micrograms per litre Specifi cation with guidance for use The objective of this Standard is mg/L milligrams per litre to specify requirements for an The objective of this Standard is to mpn/100mL Most probable environmental management system set auditable criteria for an number per (EMS) to enable an organization occupational health and safety 100 millilitre to develop and implement a management system. policy and objectives which take mSv/yr millisieverts per year The Standard is a specifi cation that into account legal requirements ML mega litres aims to encompass the best elements and other requirements to which of such systems already widely used in μS/cm microsiemens the organization subscribes, and Australia and New Zealand. per centimetre information about signifi cant environmental aspects. AS/NZS 4020:2005 AS/NZS ISO 9001:2008 Testing of products for use in contact with drinking water Quality management systems – Requirements This Standard specifi es requirements for the suitability of products for This Standard promotes the use in contact with drinking water, adoption of a process approach with regard to their effect on the when developing, implementing and quality of water. improving the effectiveness of a quality management system, to enhance These products include all items such customer satisfaction by meeting as pipes, fittings, components, and customer requirements. materials used in coating, protection, lining, jointing, sealing and lubrication For an organization to function applications in the water supply and effectively, it has to determine and plumbing industry. manage numerous linked activities. Chemicals and media used directly An activity or set of activities using for treating raw water to provide resources, and managed in order a suitable drinking water supply to enable the transformation (e.g. lime, coagulants, activated carbon, of .inputs into outputs, can be ion-exchange resins) are not covered considered as a process. by this Standard. Often the output from one process directly forms the input to the next. we value INTEGRITY

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