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Drinking Water Quality Management Plan
Service Provider No. 176
Drinking Water Quality Management Plan
Mapoon ASC Service Provider No. 176
Viridis Consultants Pty Ltd
PO Box 131
Bulimba Qld 4171
Australia
www.viridis.net.au
ABN: 49 129 185 271
Telephone: 1300 799 310
Date: 28 February 2019
Reference: 18QU39
Status: Final
© Viridis Consultants Pty Ltd 2019
Citation: Viridis Consultants 2019, Drinking Water Quality Management Plan - Mapoon ASC DWQMP, prepared for Mapoon ASC by Viridis Consultants Pty Ltd.
Drinking Water Quality Management Plan – Mapoon ASC
18QU39-REC-19-030-4.4 i June 2019
Contents 1. Introduction ................................................................................................................................... 1
2. Registered service details ......................................................................................................... 2 3. Details of infrastructure for providing the service ........................................................... 3
3.1. Schematic ....................................................................................................................................... 3 3.2. Source ............................................................................................................................................. 3 3.3. Treatment ....................................................................................................................................... 4 3.4. Reservoirs ....................................................................................................................................... 4 3.5. Distribution .................................................................................................................................... 5 3.6. Key Stakeholders ........................................................................................................................... 7
4. Identify hazards and hazardous events ................................................................................ 8 4.1. Catchment ...................................................................................................................................... 8 4.2. Bores .............................................................................................................................................. 9 4.3. Water Quality Assessment ........................................................................................................... 11 4.3.1. Raw Water ..................................................................................................................................................... 11 4.3.2. Treated Water ............................................................................................................................................. 13 4.3.3. Customer Complaints ............................................................................................................................... 14
4.4. Hazard Identification .................................................................................................................... 15 4.4.1. Hazard Identification and Risk Assessment Team ...................................................................... 15
5. Assessment of risks ................................................................................................................... 16 5.1.1. Methodology ................................................................................................................................................ 16 5.1.2. Acceptable Risk ........................................................................................................................................... 17
6. Managing risks ............................................................................................................................ 18 6.1. Risk management measures ......................................................................................................... 18 6.1.1. Critical Control Points .............................................................................................................................. 18 6.1.2. Staff Training ............................................................................................................................................... 18 6.1.3. Existing preventative measures .......................................................................................................... 18 6.1.4. Proposed preventative measures ....................................................................................................... 19 6.1.5. Cybersecurity ............................................................................................................................................... 19
6.2. Operation and maintenance procedures ....................................................................................... 19 6.3. Management of incidents and emergencies ................................................................................. 21 6.3.1. Alert Levels ................................................................................................................................................... 21 6.3.2. Response Actions ....................................................................................................................................... 21 6.3.3. Process for incident reporting ............................................................................................................. 24 6.3.4. Notification of Alerts about water quality ....................................................................................... 28 6.3.5. Staff Training for Incident Response ................................................................................................. 28
6.4. Service Wide Support – Information Management ..................................................................... 29 6.5. Customer Complaints ................................................................................................................... 30
7. Operational and verification monitoring programs ...................................................... 31 7.1. Regular Checks ............................................................................................................................ 31 7.2. Operational Monitoring ................................................................................................................ 31 7.3. Verification Monitoring ............................................................................................................... 35
Appendices Critical Control Points ................................................................................................................................................................................. A Boil Water Alert .............................................................................................................................................................................................. B Do Not Drink Alert ......................................................................................................................................................................................... C Drinking Water Alert Lifted ...................................................................................................................................................................... D
Figures Figure 1 Map of the Mapoon region ....................................................................................................................................................... 1
Drinking Water Quality Management Plan – Mapoon ASC
18QU39-REC-19-030-4.4 ii June 2019
Figure 2 Schematic for the Mapoon scheme ....................................................................................................................................... 3 Figure 3 Mapoon reticulation schematic .............................................................................................................................................. 6 Figure 4 Map of the Wenlock catchment .............................................................................................................................................. 9 Figure 5 Mapoon supply scheme bore locations ............................................................................................................................ 10 Figure 6 Typical bore compound construction (RN 92522) ..................................................................................................... 10 Figure 7 Treated Water Free Chlorine (November 2017 – November 2018) .................................................................. 13 Figure 8 Treated Water pH (November 2017 – November 2018) ......................................................................................... 13 Figure 9 Preliminary Incident/Emergency Flow Chart .............................................................................................................. 22 Figure 10 Actions and Reporting for Detection of E. coli ........................................................................................................... 25 Figure 11 Actions and Reporting for Detection of Chemical Parameters above ADWG Health Guideline Values
................................................................................................................................................................................................................... 26 Figure 12 Actions and Reporting during a Disaster ..................................................................................................................... 27
Tables Table 1 Registered service details ........................................................................................................................................................... 2 Table 2 Details of bores ................................................................................................................................................................................ 4 Table 3 Treatment details ........................................................................................................................................................................... 4 Table 4 Reservoir details ............................................................................................................................................................................. 5 Table 5 Summary of the reticulation system ...................................................................................................................................... 5 Table 6 Mapoon drinking water supply key stakeholders ........................................................................................................... 7 Table 7 Summary of catchment characteristics ................................................................................................................................ 8 Table 8 Raw water quality ....................................................................................................................................................................... 11 Table 9 Summary of treated water verification results (November 2017-‐ July 2018) ................................................. 14 Table 10 Risk review team (January 2019 Review) ..................................................................................................................... 15 Table 11 Risk review team (Initial assessment in 2016) ........................................................................................................... 15 Table 12 Risk assessment likelihood descriptions ....................................................................................................................... 16 Table 13 Risk assessment consequence descriptions ................................................................................................................. 16 Table 14 Likelihood-‐consequence matrix used for the assessment ...................................................................................... 17 Table 15 Risk assessment uncertainty descriptions .................................................................................................................... 17 Table 16 Critical control points for the Mapoon drinking water supply system. ............................................................ 18 Table 17 Mapoon water supply procedures .................................................................................................................................... 20 Table 18 Overview of alert levels ......................................................................................................................................................... 21 Table 19 Summary of actions for each alert level ......................................................................................................................... 23 Table 20 Incident reporting requirements ....................................................................................................................................... 24 Table 21 Vulnerable consumers ........................................................................................................................................................... 28 Table 22 Information Management Activities/Document Summary ................................................................................... 29 Table 23 Regular checks and inspections ......................................................................................................................................... 31 Table 24 Operational monitoring locations ..................................................................................................................................... 31 Table 25 Operational monitoring details .......................................................................................................................................... 33 Table 26 Verification monitoring sampling sites .......................................................................................................................... 35 Table 27 Verification monitoring program ...................................................................................................................................... 35
Drinking Water Quality Management Plan – Mapoon ASC
18QU39-REC-19-030-4.4 iii June 2019
Document History and Status Revision Date Approved by Initials Details
4.1 22.02.19 Tasleem Hasan TH Internal Review
4.2 28.02.19 Tom Smith TS MASC Review
4.3 31.05.19 Tom Smith TS Updated based on DNRME comments.
4.4 3.06.19 Tom Smith TS Updated based on DNRME comments.
Author: Glen Luscombe
Project manager: Glen Luscombe
Name of client: Mapoon ASC
Name of project: Drinking Water Quality Management Plan
Name of document: Mapoon ASC DWQMP Document number REC-19-030
Document version: 4.4
Project number: 18QU39
The Mapoon Aboriginal Shire Council considers this document contains matters relating to the business and financial affairs of Mapoon Aboriginal Shire Council and its disclosure may be contrary to the public interest under section 49 and Schedule 4 of the Right to Information Act 2009 (RTI Act). Mapoon Aboriginal Shire Council would therefore be substantially concerned if this document was to be released publicly. Given this, Mapoon Aboriginal Shire Council provides this copy of the Drinking Water Quality Management Plan to the recipient agency on the understanding that if the agency receives a Right to Information (RTI) request that captures this document; it will formally consult with Mapoon Aboriginal Shire Council under section 37 of the RTI Act before a decision is made on the RTI request.
18QU39-REC-19-030-4.4 1 June 2019
1. Introduction
This Drinking Water Quality Management Plan (DWQMP or plan) documents the risk management approach taken by Mapoon Aboriginal Shire Council (MASC) to maintain and improve the safety of the Mapoon drinking water supply scheme. The document is a ‘living document’, representative of current practice and must be regularly reviewed and updated.
The DWQMP has been developed to meet the requirements of the Water Supply (Safety and Reliability) Act 2008 (the Act). The structure and content of this plan was based on the Drinking Water Quality Management Plan Guideline (DNRME, 2018).
This plan contains or references the relevant documentation which underpins the drinking water quality management for the Mapoon water supply scheme. The following documents make up the DWQMP:
• Main DWQMP Document (this document) • Risk Register and Risk Management Improvement Plan (RMIP) • Critical Control Point (CCP) Procedures
The Mapoon Aboriginal Shire Council Local Government area is situated in a coastal area of far north Queensland approximately 80 km north of Weipa and is the land described as lots 4 and 6 on Crown Plan WP53 and lot 2 on Crown Plan WP839186 and is comprised of an area of about 183,960 hectares (refer Figure 1).
Figure 1 Map of the Mapoon region
18QU39-REC-19-030-4.4 2 June 2019
2. Registered service details
Details for the water supply service are provided in Table 1.
Table 1 Registered service details
Service description Details
Service Provider Identification Number (SPID) 176
Council Name and Contact Details Mapoon Aboriginal Shire Council Red Beach Road Mapoon 4874 ABN: 15 093 924 706 Phone: 07 4082 5203 Technical Services E-Mail: [email protected] CEO E-Mail: [email protected] Website: http://www.mapoon.qld.gov.au
Communities serviced Mapoon
Current population (2019)* 325
Current connections (2019) 126
Current demand (2019) ML/day 0.9
Projected population (2029)* 342
Future connections (2029) 132
Future demand (2029) ML/day 0.95
*Note, population projected from 2016 census data using an annual growth rate of 0.58% based on similar localities published in the Queensland Government Projected Population (medium series) 2016.
18QU39-REC-19-030-4.4 3 June 2019
3. Details of infrastructure for providing the service
3.1. Schematic
A schematic for the supply system is provided in Figure 2.
Figure 2 Schematic for the Mapoon scheme
3.2. Source
Source water for the Mapoon supply scheme is provided by four bores drawing water from the aquifer (refer Table 2). Bores are operated on a duty/duty/duty/standby basis. The bore field includes a fifth bore, however this is used for irrigation supply.
The bores are protected are secured in a fenced compound and sealed to prevent surface water infiltration. During power outages, power to the borefield is supplied through a backup generator.
18QU39-REC-19-030-4.4 4 June 2019
The capacity of the bores is regularly challenged by demand, and Council will be installing an additional bore in 2020. This will help to ensure water security during peak periods and provide redundancy where equipment failure or water quality issues arise from a bore.
Table 2 Details of bores
Item Bore 1 Bore 2 Bore 3 Bore 4 Bore 5
Bore Number RN 92524 RN 92522 RN 92525 RN 92523 RN 72882
Service Drinking Water Supply
Drinking Water Supply
Drinking Water Supply
Drinking Water Supply Irrigation
Constructed 1996 1996 1996 1996 1989
Aquifer Type Unconfined Unconfined Unconfined Unconfined Unconfined
% of Supply 30% - 3L/s 30% - 3L/s 30% - 3L/s 10% - 1L/s 3L/s
Reliability Good – 100% Good – 100% Good – 100% Good – 100% Good – 100%
Pump Submersible Pump Grundfos SP8A-12
Submersible Pump Grundfos SP8A-12
Submersible Pump Grundfos SP8A-12
Submersible Pump Grundfos SP8A-12
Submersible Pump Grundfos SP8A-12
Capacity 8m3/hr 8m3/hr 8m3/hr 3m3/hr 8m3/hr
Bore Depth 30m 30m 30m 30m 30m
Bore Head Details Raised and sealed Raised and sealed Raised and sealed Raised and sealed Raised and sealed
Casing and Materials PVC, Cased PVC, cased PVC, Cased PVC PVC, Cased
Water Quality Issues Low pH Low pH Low pH Low pH Low pH
3.3. Treatment
Raw water supplied from the bores is pumped to Mapoon WTP for treatment. The plant is operated manually by operators based on reservoir level, including start-stop of the plant. At Mapoon WTP, the following treatment processes are undertaken:
• pH Correction using soda ash • Disinfection using chlorine gas.
Soda ash dosing and chlorination systems are activated on start-up of the plant. Operators adjust dosing levels manually based on grab sampling results. No online instruments are installed in the plant. Further details on the treatment system are available in Table 3.
Table 3 Treatment details
Parameter Details
Process Soda Ash Dosing Gas Chlorination
Design capacity (20-hour operation) 0.9 ML/d
Daily flow range 0.4-0.9 ML/d
Chemicals added Soda Ash Chlorine
Standby chemical dosing facilities (Y/N) No
Bypasses/variations No
Alarms No PLC/SCADA installed for process alarms
3.4. Reservoirs
Treated water is stored in a ground level reservoir and is delivered to the reticulation system by a town water pump station. During power outages, the ground level reservoir is isolated and treated water is pumped to the
18QU39-REC-19-030-4.4 5 June 2019
elevated reservoir, using gravity distribution to the reticulation network. Details of the reservoirs are available in Table 4.
A replacement reservoir is planned to replace the ground level reservoir in 2020. This renewal will increase the storage capacity to approximately 1.2ML, providing an increased buffer for equipment or treatment failure.
Table 4 Reservoir details
Parameter Reservoir 1 Reservoir 2
Capacity 0.22ML 50kL
Location Mapoon WTP Mapoon WTP
Type Reinforced concrete, ground level tank. Steel tank, elevated approximately 20m from ground level.
Roofing Sloped corrugated steel roof, runoff directed off tank.
Sloped corrugated steel roof, runoff directed off tank.
Vermin-proofing Openings covered in vermin-proof mesh. Openings covered in vermin-proof mesh.
Cleaning schedule Tank inspections on a five-year basis. Tank drained while not in use.
Filling Manual filling control using a float and slug indicator on the tank. Manual filling control.
3.5. Distribution
Water from the ground level reservoir is pumped into the reticulation using a town water supply pump station. During a power outage, the reticulation system is gravity fed from the elevated storage tanks.
The distribution and reticulation of water services is largely fed from PVC and HDPE pipework, although some legacy asbestos cement remains. There is no copper or steel pipework in the council reticulation system, although copper and steel may be used in customer piping. A summary of the reticulation system is available in Table 5.
A monthly flushing program is conducted to maintain chlorination at dead ends.
Table 5 Summary of the reticulation system
Parameter Details
Pipe materials PVC HDPE Asbestos Cement
Age range Some areas installed in 2002, with areas renewed as required.
Length of mains 20km
Dead ends and high detention period areas
Cullen Point End Cullen Point Valve 2 Thungoo End 1 Thungoo End 2 Central Valve All dead ends are flushed on a monthly basis to maintain chlorine levels.
Areas of low pressure None.
A schematic of the reticulation system, noting sampling and hydrant locations, is provided in Figure 3. Sampling points are used for operational and verification sampling. For more information on operational and verification monitoring, refer to section 7.
18QU39-REC-19-030-4.4 6 June 2019
Figure 3 Mapoon reticulation schematic
18QU39-REC-19-030-4.4 7 June 2019
3.6. Key Stakeholders
Key stakeholders for the Mapoon drinking water supply scheme are noted in Table 6.
Table 6 Mapoon drinking water supply key stakeholders
Organisation Contact details Relevance to management of drinking water quality
How the stakeholder is engaged in the DWQMP
Mapoon Community Various - Contacted via letter drops, posters, door knocking and word of mouth.
Consumers Informed of water quality issues as they arise.
Ixom Enquiries: 1300 559 262 Emergencies: 1800 033 111
Provides chlorine Chlorine is ordered as required.
Northern Chemicals, Cairns Phone: 4035 4622 [email protected]
Provides soda ash Soda ash is ordered as required.
DNRME, WSR
Water Supply Regulation Incident Hotline: 1300 596 709 (24/7) Email: [email protected]
Regulator
Report incidents on 1300 596 709 when detection of E. coli and chemical parameters above health guideline value in ADWG in potable water supply; Report an event likely to affect drinking water quality in potable water supply. Approval of the DWQMP.
Queensland Health, Public Health Unit
Director Environmental Health Ph.: 4226 5604
Point of contact for assistance with public health issues related to water supply.
Provides advice during public health incidents.
Cairns Regional Council Water Laboratory
Laboratory Manager Ph.: 4044 8344
NATA certified laboratory where water samples are sent for analysis.
Scheduled water samples from the drinking water supply are collected and sent to this laboratory for analysis.
CEO and Elected Council As per Council directory Overall management, budget and finance
Kept up to date and informed of water operations. Submits Overall responsibility for DWQMP.
Mapoon Primary Health Care Centre
Ph.: 4082 9400 Address: Red Beach Road, Mapoon QLD 4874
Vulnerable consumer Informed during water quality incidents.
School Ph.: 4082 9333 Address: Red Beach Road, Mapoon QLD 4874
Vulnerable consumer Informed during water quality incidents.
A new aged care centre is being constructed in Mapoon and will be contacted for inclusion/engagement in the DWQMP process as the centre opens.
18QU39-REC-19-030-4.4 8 June 2019
4. Identify hazards and hazardous events
4.1. Catchment
Mapoon township is situated at the mouth of the Wenlock River, which is fed by its associated tributaries (refer Figure 4) of the Wenlock River. The reach of the catchment extends back to the Iron Range approximately over 240Km. The main water source is derived from aquifers in the Mapoon Peninsula, fed from the Wenlock catchment.
The Wenlock River catchment is heavily forested, containing dense bushland and swamps. The soil in the region predominantly consists of bauxite in the top layers with sandy, loamy soils in the lower layers. The area does not support agriculture or pasture for grazing, the main industry is bauxite mining which is 30 km away, and unlikely to impact the aquifer.
Mapoon experiences two distinct seasons, wet and dry. The wet season runs from late November to late March and the dry season for the remainder of the year. Mapoon receives most of its annual rainfall in the form of heavy thunderstorms and/or cyclonic weather conditions. The area suffers occasional flooding and bushfires, both of which do not interfere with the water supply aquifer. There have been no occasions where water supply from the aquifer has been limited.
Table 7 Summary of catchment characteristics
Characteristic Details
Area 7435 km²
Topography Flat
Soil type Sand (Bauxite) and soil
Monthly rainfall (min, max, average) Min: 1400mm per annum Max: 2600mm per annum Average: 2200mm per annum
Incidence of flooding and bushfires Occasional flooding, bushfires (dry season only)
Land use Low density rural and residential Swamps, forest and bushland
Agriculture, industry, mining Bauxite mining
18QU39-REC-19-030-4.4 9 June 2019
Figure 4 Map of the Wenlock catchment
4.2. Bores
The water supply system is fed from four bores located in a single borefield located near the Mapoon township. The bores are located within a 1km zone (refer Figure 5). The bores used to feed the drinking water supply system are:
• RN 92522 • RN 92523 • RN 92524 • RN 92525
18QU39-REC-19-030-4.4 10 June 2019
Figure 5 Mapoon supply scheme bore locations
The bores are protected are secured in a fenced compound and sealed to prevent surface water infiltration. Bore heads are raised above the pad surface to reduce the likelihood of surface water infiltration (refer Figure 6), and bores are fenced to prevent vandalism or damage from wildlife. For further information about bore infrastructure, refer to section 3.2.
Figure 6 Typical bore compound construction (RN 92522)
.