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MOUNT PETER STRUCTURE PLAN PART 5 - TECHNICAL REPORT WATER SUPPLY, SEWERAGE AND RECYCLED WATER

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MOUNT PETER MASTER PLANNING PART 5 - WATER SUPPLY, SEWERAGE & RECYCLED WATER TECHNICAL REPORT

This report is a Technical background report that informs the Mount Peter Structure Plan. Specifically, this report is in support of, and in response to, elements of item 3.3 (Integrated Water Cycle Management Plan / Waterways and Catchment Management) of Section 4.1 (Outputs) of the Mount Peter Master Planning Specification. DISCLAIMER This Technical Report is one of a series of reports which forms part of the draft Structure Plan for Mount Peter. Please note that this Technical Report is a draft document only. Whilst every care is taken to ensure the accuracy of this Technical Report and draft Structure Plan, Cairns Regional Council (CRC) accepts no liability for the accuracy of or inferences from the material contained in this publication, or for any action as a result of any person's or group's interpretations, deductions or conclusions relying on this material. The CRC accepts no liability for any loss, damage or injury (including consequential loss, damage or injury) from any use of this Technical Report and draft Structure Plan. COPYRIGHT This document is and shall remain the property of the Cairns Regional Council. Using or copying this document or any part of it without specific authorisation is absolutely prohibited. P.O. Box 359 Cairns, Qld., 4870 Tel: (07) 4044 3044 Fax: (07) 4044 302

Document Control

Version Date Author Reviewer

Name Initials Name Initials

Ver A May 2010 Christopher Smith CS MPMPG AS

MOUNT PETER MASTER PLANNING GROUP

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WATER SUPPLY, SEWERAGE AND RECYCLED WATER

TECHNICAL REPORT

TABLE OF CONTENTS

1 BACKGROUND ................................................................................................................... 1

1.1 STUDY OBJECTIVE ................................................................................................. 1 1.2 STUDY AREA ............................................................................................................ 1 1.3 RELEVANT DOCUMENTS ....................................................................................... 1

2 ASSUMPTIONS/METHODOLOGY ..................................................................................... 3

2.1 EQUIVALENT POPULATION .................................................................................... 3 2.2 DESIRED STANDARDS OF SERVICE .................................................................... 5 2.3 FLOW ASSESSMENT ............................................................................................. 10 2.3.1 BASE CASE ............................................................................................................ 10 2.3.2 INTEGRATED WATER CYCLE MANAGEMENT DEMANDS ................................ 11 2.4 METHODOLOGY .................................................................................................... 13

3 OPPORTUNITIES/CONSTRAINTS .................................................................................. 14

3.1 WATER SUPPLY .................................................................................................... 14 3.2 WASTEWATER ....................................................................................................... 15 3.3 WATER CYCLE MANAGEMENT ............................................................................ 16

4 ISSUES .............................................................................................................................. 17

5 DISCUSSION ..................................................................................................................... 18

5.1 WATER CONSERVATION ...................................................................................... 18 5.1.1 QUEENSLAND DEVELOPMENT CODE ................................................................ 18 5.2 POTABLE WATER SUBSTITUTION ...................................................................... 18 5.2.1 RECYCLED WATER ............................................................................................... 18 5.3 POTABLE WATER SUPPLY ................................................................................... 19 5.3.1 WATER SUPPLY PROJECTS ................................................................................ 19 5.3.2 STORAGE ............................................................................................................... 20 5.3.3 DISTRIBUTION ....................................................................................................... 21 5.4 WASTEWATER ....................................................................................................... 21 5.4.1 TREATMENT ........................................................................................................... 21 5.4.2 SEWERAGE COLLECTION .................................................................................... 22

6 SUMMARY RECOMMENDATIONS .................................................................................. 23

6.1 SUMMARY .............................................................................................................. 23 6.2 ACTION PLAN ......................................................................................................... 26

APPENDICES APPENDIX A SUPPORTING INFORMATION

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EXECUTIVE SUMMARY

This report considers water supply, sewerage and recycled water issues relating to development of the Mount Peter Master Planned Area (MPA) as part of an integrated approach to water cycle management.

In order to assess water and sewerage issues an equivalent population (EP) for water and sewerage had initially been assumed between 58,103 to 77,138 EP (i.e. total including non-residential) based on an initial estimate of the developable area of 1,236ha excluding the industrial area to the north east. The current estimate is 57,946 EP and is composed of 51,755 EP for the residential component based on 18,484 dwellings at 2.8 EP per ET for water and sewerage in accordance with CRC and FNQROC and an allowance of 10% for the non-residential component (equivalent to approximately 32EP/ha) and a further 1,000 EP for open space/community. The industrial area to the north east with the exception of the parcel fronting Deppeler Road (Lot 3 SP 105994) is proposed to be serviced by existing and proposed water supply and sewerage infrastructure on Thomson Road and in the Edmonton area. Therefore, planning and the future infrastructure charges for this land will be prepared and considered by Council separately to Mount Peter and has been excluded from this analysis. A small area of the north east industrial area has been allowed for in Mount Peter and is an additional approximate 1,350EP (i.e. 43.4 ha at approximately 32EP/ha). Therefore, the total population for Mount Peter is 59,296EP. The total industrial area to the north east is approximately 251ha and at 32 EP per ha is equivalent to approximately 8,043EP. Ultimately, the EP demand is dependant on the nature of the ultimate industrial and commercial uses. Recycled water provision to the industrial land to the north east will depend on final end use which is currently unknown. Therefore, it is not possible to forecast and plan the infrastructure requirements. However, a proposed supply of recycled water to the whole of the north east area has been allowed through the provision of nominal trunk mains to the area that will need to be addressed during Master Planning or through individual infrastructure agreements as re-use opportunities are defined. The water and sewerage demands will also be refined along with the infrastructure during Master Planning.

Based on the above water and sewerage population, the forecast average day (AD) water demand for the development would be up to 20.8 ML/day and the sewage average dry weather flow (ADWF) would be up to 20.6 ML/day. For the current estimated population these demands would be approximately 15.6ML/d and 15.4 ML/d for AD water demands and ADWF sewage demands respectively and 16 ML/d and 15.7 ML/d including the small area of the north east industrial area respectively.

The current key water sources for Cairns; Copperlode Falls Dam, with intakes at Crystal Cascades and Behana Creek have been identified as having insufficient capacity to meet the forecast future demands and growth. The State Government, local governments and key regional stakeholders have developed a Draft Regional Water Supply Strategy to meet the future water supply demands and accommodate the significant population growth anticipated for the region including Mount Peter. This strategy includes for the development of new water supplies for Cairns.

Cairns Regional Council have investigated two key future water supplies which will be needed to support the ultimate development for Mount Peter; the Barron River Water Scheme and the Mulgrave River Aquifer as outlined in the Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009). This report has been adopted by Council and recommends the Barron River Water Scheme and the Mulgrave River Aquifer be developed starting with Stage 1 of the Mulgrave River Aquifer. In addition, Cairns Regional Council are implementing measures to reduce per capita demand to defer the timing of these new water supplies. The new water supply sources and timing will need to continue to be

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progressed to provide certainty that water is available for the ultimate development. This works will benefit other areas of Cairns. Therefore, the cost of these works will also be shared. The sharing of costs of will need to be refined as developed by Council as part of their planning. The development of the Mulgrave River Aquifer as recommended will require a future Behana- Mulgrave Water Treatment Plant and associated infrastructure and as part of this planning, Cairns Regional Council have identified a potential site in the southern Mount Peter area. The associated infrastructure includes a main through the site that alignment for which will need to be considered during Master Planning.

There is an existing 800mm diameter trunk main that runs along the eastern boundary of the Mount Peter site between Gordonvale and Edmonton that has been identified by Cairns Regional Council to provide a future connection point(s) to supply the MPA, possibly near Maitland Road. The connection point would supply dedicated trunk mains to the proposed local reservoir storage for Mount Peter. The potential exists to use the existing 400mm diameter main to provide a direct connection into the initial stages of development.

Additional local storage capacity will be required to service the development. This can be staged to match future population growth during Master Planning. In discussions with Cairns Regional Council the existing Draper Road reservoir has been identified to have spare capacity to service the initial stages of development. However, a new main on Peterson Road and storage at Coombak Close is proposed for the northern area and will be confirmed during Master Planning. There is a potential opportunity to recommission the existing Coombak Close Reservoir to defer the timing of the future reservoir(s). Total storage capacity of approximately 36ML (potable and non-potable) will ultimately be required (based on an equivalent population for water of 59,296EP) and Cairns Regional Council has identified potential reservoir sites to service Mount Peter as shown on Figure 1 together with the indicative trunk water supply infrastructure.

High level storage or booster pump station(s) will be required to supply higher elevation areas depending on the final developable area and will be confirmed during Master Planning. The internal infrastructure requirements can not be finalised until the developable area and yields are confirmed during Master Planning.

A sewerage planning study into the existing nearby Edmonton and Gordonvale Wastewater Treatment Plant catchments commissioned by Cairns Regional Council has completed a report the Edmonton – Gordonvale Sewerage Planning Report (Arup, February 2010). Flow from Mount Peter is proposed to be directed to both of these plants in the interim using existing and interim spare capacity following augmentation as identified initially in the Edmonton Gordonvale Sewerage Planning Network Reserve Capacity for Mount Peter development (Arup, 28 July 2009) and confirmed in the Edmonton and Gordonvale Sewerage Planning Report (Arup, February 2010). There is the option to make the interim transfer to Gordonvale permanent subject to an augmentation of the existing Treatment Plant.

Given the scale of the proposed development and need to provide recycled water, a new wastewater and recycled water treatment plant in proximity to the development area is proposed based on the Mount Peter MPA to Edmonton WWTP Sewerage Infrastructure Investigation (Cardno, June 2009) that identified there is an additional cost in transporting the sewage and returning recycled water approximately 7km compared to the option of local treatment. However, the option of local treatment is subject to obtaining the necessary regulatory approvals and appropriate land during Master Planning and design and is likely to be required in 5 to 10 years depending on growth.

The treatment of sewage from Mount Peter will need to consider the management of wastewater/treated effluent generated from the development recognising the Far North Queensland Regional Plan 2009 -2031 target of 100% reuse of average dry

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weather flows by 2018 and the requirement to eliminate wastewater point source discharges where possible. Therefore, the plant will need to incorporate sufficient onsite wet weather storage. Recycled water infrastructure in the MPA is mandatory and will assist in achieving the reuse target. However, the plant is likely to require a provision of land for the irrigation and disposal of effluent over and above that reused by households, industry in the north east and any potential agricultural irrigation opportunities. For the purposes of this initial study, it is assumed that potable substitution would apply to toilet flushing and outdoor uses, which is equivalent to approximately 55% of household demand. Fire fighting is proposed from the potable network in accordance with FNQROC. The recycled water infrastructure required in Mount Peter will require a network of pipes, pump stations and storages similar to the proposed water albeit at a different size and will be supplied from the proposed Mount Peter wastewater/recycled water treatment plant and will be confirmed during Master Planning. The proposed interim sewerage discharge points for the development ultilises existing and proposed spare capacity in the existing networks at the GO5 pump station part of the existing Gordonvale network and the ED1 pump station (or upstream gravity trunk main at Mill Rd) part of the existing Edmonton network depending on proposed augmentations. Two pump stations and associated rising mains are proposed from Mount Peter to discharge to these points. The detailed internal sewerage infrastructure requirements cannot be determined until the developable area, yields and survey and final surface levels are confirmed during Master Planning. However, the natural contours across the site appear to be generally suitable for a gravity based trunk collection system as indicated on Figure 3. The proposed location for key trunk sewers is along natural drainage paths and creek lines. However, it is likely that some localised pump stations will likely be required during Master Planning. The design requirements for gravity sewers on steep slopes will need to be considered during detailed design.

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1 BACKGROUND

1.1 STUDY OBJECTIVE

This report considers the existing water supply and sewerage trunk infrastructure available within the vicinity of the Mount Peter MPA and provides an indication of the additional external infrastructure required to maintain Desired Standards of Service following the inclusion of the proposed development. This will be completed during Master Planning pending the finalisation of the loads and availability of detailed survey data.

1.2 STUDY AREA

The location and extent of the Mount Peter MPA is illustrated on the Figures contained in Appendix A.

The topography of the site varies significantly between the ridges which form the western boundary with the Wet Tropics World Heritage Area, down to low lying areas to the east along the Bruce Highway.

1.3 RELEVANT DOCUMENTS

The following studies have provided background information for this report:

• Far North Queensland Regional Plan 2009 - 2031;

• FNQ Draft Regional Water Supply Strategy, September 2007;

• Preliminary State Agency Position Paper V3;

• Southern Corridor Water and Wastewater Investigation, SKM, December 2007 (Note: document was lodged with Council in support of an earlier DA application for CEC and Straguzi);

• The Cleaner Seas Project Concept Design Report for Edmonton (Hold Point 2), November 2005;

• The Cleaner Seas Project Concept Design Report for Southern (Hold Point 2) resubmission, March 2006;

• Edmonton Wastewater Treatment Plant Planning Report, March 2004;

• Planning Report for Gordonvale Sewerage, August 1991;

• Gordonvale Sewerage Treatment Plant Supplementary Planning Report Alternatives, June 1992;

• FNQROC Development Manual Operational Works Design Guidelines, Draft Version 07/08;

• Water Quality Guidelines for Recycled Water Schemes, Draft June 2008;

• Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council , March 2009) which has been adopted by Council;

• Edmonton and Gordonvale Sewerage Planning Report (Arup, February 2010)*;

• Edmonton Gordonvale Sewerage Planning Network Reserve Capacity for Mount Peter development (Arup, 28 July 2009); and

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• Mount Peter MPA to Edmonton WWTP Sewerage Infrastructure Investigation (Cardno, June 2009).

There are a few minor additional comments from Cairns Regional Council on the above study(*) to be addressed before it is finalised. However, these have not been identified as affecting the assumptions and outcomes incorporated in this report.

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2 ASSUMPTIONS/METHODOLOGY

2.1 EQUIVALENT POPULATION

The Equivalent Population (EP) for water, recycled water and sewerage for the development will be determined by the allowable developable footprint, density, land use breakdown and other factors during Master Planning. The Table below outlines the initial provisional estimate of the future residential population for the purpose of estimating water, recycled water and sewerage demand.

Estimated Residential Equivalent Population

Land use Quantity Unit Source

Developable area 1,236 Ha Assumptions Report

Residential population density 15-20 dw/ha Assumptions Report

Equivalent population (water) density 2.8 EP/dw CRC & FNQROC

Residential population 51,912 – 69,216 EP Calculated for water and sewerage demands

Additional water, recycled water and sewerage demand or EP will be associated with non-residential land uses such as retail, commercial and community facilities. Based on a typical master planned community structure, the non residential EP had been estimated to be equivalent to approximately 10% of the residential development EP. The table below includes a provisional estimate of the total development population, to be finalised during Master Planning.

In addition, a small demand will be associated with the open space and recreational land uses. As outlined in the Assumptions Report, open space is expected to be equal to approximately 4ha/1000 persons. Therefore, the open space area would constitute around 200ha. Based on a load of 5 EP/ha, this equates to an estimated total of 1,000 EP.

Estimated Total Equivalent Population for Water and Sewerage


Residential population 51,912 – 69,216 EP Calculated

Non-residential population % 10% % Residential

EP Typical master planned

community

Non-residential population 5,191 - 6,922 EP Calculated

Open space population 1,000 EP Calculated for water. Assummed none or minimal sewerage

demand

Total population 58,103 - 77,138 EP Calculated for water and sewerage demands

Small area of the north east industrial area

1,350 EP Calculated for water and sewerage demands

Total population including 59,453 EP Calculated for water and

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a small area of the north east industrial land

sewerage demands

The current estimate is 57,946 EP and is composed of 51,755 EP for the residential component based on 18,484 dwellings at 2.8 EP per ET for water and sewerage in accordance with CRC and FNQROC and an allowance of 10% for the non-residential component (equivalent to approximately 32EP/ha) and a further 1,000 EP for open space/community. The current estimate of 57,946 EP is similar to the initial estimate range of 58,103 EP. The industrial area to the north east with the exception of the parcel fronting Deppeler Road (Lot 3 SP 105994) is proposed to be serviced by existing and proposed water supply and sewerage infrastructure on Thomson Road and in the Edmonton area. Therefore, planning and the future infrastructure charges for this land will be prepared and considered by Council separately to Mount Peter and has been excluded from this analysis. A small area of the north east industrial area has been allowed for in Mount Peter and is an additional approximate 1,350EP (i.e. 43.4 ha at approximately 32EP/ha). Therefore, the total population for Mount Peter is 59,296EP. The industrial area to the north east is approximately 251ha and at 32 EP per ha is equivalent to approximately 8,043EP.

Recycled water provision to the industrial land to the north east will depend on final end use which is currently unknown. Therefore, it is not possible to forecast and plan the infrastructure requirements. However, a proposed supply of recycled water to the whole of the north east area has been allowed. The water and sewerage demands will also be refined along with the infrastructure during the master planning process.

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2.2 DESIRED STANDARDS OF SERVICE

Cairns Regional Council is committed to maintaining and increasing its standards of services to its customers. The standards of service relevant to this project have been sourced from the FNQROC Development Manual Operational Works Design Guidelines Draft Version 07/08 unless otherwise advised by Council. These are summarised below. Adopted Desired Standards of Service for Water Supply

# Design Criteria Value

Water Supply Flows:

1 Average Daily Consumption (AD) 270 L/EP/d (as advised by Council. See note below) 2 Mean Day Maximum Month (MDMM) 1.5 x AD 3 Peak Day (PD) 2.25 x AD 4 Peak Hour (PH) 1/12 x PD Equivalent Demands1:

5 Typical Detached Dwelling 2.8EP/Lot as advised by Council (equivalent to average of lots 401m2 – 900m2 and lots < 400m2 in FNQROC)

6 Units > 3 bedrooms 0.4EP/Unit + 0.6EP/bedroom

7 Units = 3 bedrooms 2.2EP/Unit

8 Units = 2 bedrooms 1.6EP/Unit

9 Units < 2 bedrooms 1.0EP/Unit 10 Caravan Parks 1.2EP/ Van Site or Camping Site 11 Shops/Office 1.0EP/ Per 90m² GFA Pressure Parameters

12 Minimum Pressure 22 metres head at peak hourly consumption

13

Minimum Pressure Location For lots at or below road reserve level at the property boundary.

For lots above the road reserve level at a nominated level practical building site. Or in the absence of a natural or benched building site the mean lot level shall be used.

14

Minimum Pressure Network Condition (for modelling from a reservoir).

Based on the reservoir level for Peak Hour of the third day of three consecutive Peak Day events (for dynamic models).

In the absence of dynamic model results the minimum reservoir level shall be assumed at 15% of storage height.

Liaise with Council to confirm minimum pressure constraints available at the connection to the existing system.

15 Maximum Pressure 60 metres head2

16 Maximum Pressure Location At the building pad

17 Maximum Pressure Network Condition (for modelling from a reservoir).

Based on reservoir level at 95 percent of top water level

Fire Fighting Parameters:

18 Residential (i.e. An area comprising of predominantly residential dwellings of a maximum of 3 storeys)

1 at 15 L/s for 2 hours

19 Commercial (i.e. An area comprising of shop and office accommodation of a maximum of 3

1 at 30 L/s for 4 hours

For schemes serving a population of less than 1000 a fire

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storeys) and Industrial flow of 15 L/s for 2 hours should be satisfactory except where a special hazard or risk development exists

20

High Risk (i.e. A development where there is a probability of a fire occurring or there is a high cost of resultant damage (personal injury or property)

Adopt a special hazard or risk fire

21 Residual pressure Minimum of 12m at hydrant

22 Dynamic fire flow analysis The base flow will be that represented by the peak demand section of the diurnal flow curve for the adopted peak day, taking into account the period of the design fire event

23 Static fire flow analysis

Peak hour for schemes servicing more then 3000 population;

⅔ of peak hour for schemes servicing less than 2000 population;

An interpolation between ⅔ PH and PH for schemes servicing between 2000 and 3000 population

Storage Parameters

24 Reservoirs (ground level) 3 (PD-MDMM) + (greater of Emergency Storage/Firefighting Storage)

25 Elevated reservoir

6 (PH – MDMM) 12

+ firefighting reserve Pump Parameters

26 Treated water pumps feeding a ground level reservoir

MDMM over 20 hours

27

Treated water pumps feeding an elevated reservoir

Capacity (L/s) =

6PH – reservoir operating volume

6 x 3600

Volume in litres

28 Standby pumps Standby pump capacity to match the largest single unit pump capacity

29 Reticulation booster pump station PH + fireflow

30

Pumped System Peak instantaneous flow + fireflow

This situation may exist in smaller systems if variable speed pumps would replace any elevated storage. In these instances it would be necessary to calculate instantaneous flow based on concurrent demand. This would exceed PH by a significant margin.

Pipeline Parameters:

31 Pipe capacity – Trunk & Reticulation Mains

Size for PH + Fire Flow

32 Friction Equation Hazen-Williams

33 Maximum Velocity 2.5m/s

34 Minimum Velocity N/A

Headloss Calculations3:

35 Hazen-Williams headloss calculation shall be adopted

36 Pipe Diameter < 150mm C =100

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37 150mm < Pipe Diameter > 300mm C =110

38 300mm < Pipe Diameter > 600mm C = 120

39 Pipe Diameter >600mm C = 125 1. For undeveloped land equivalent populations shall be calculated in accordance with the maximum allowable

population density in the Planning Scheme. 2. Where the pressure in a main exceeds 600 kPa, Council shall require the installation of Pressure Reducing

Valves (PRV) that may (at Council’s discretion) include telemetry control. Prior to proceeding with any design, Council shall be provided with details of the area affected and the number of lots involved.

3. The C values take into account losses for pipe fittings such as bends, valves, tees, crosses etc and the effect of pipeline ageing.

Cairns Regional Council has advised that an EP per Domestic Connection of 2.8 Equivalent Persons/Equivalent Domestic Connection (EP/EDC) applies. This is equivalent to the average occupancy for single family dwellings for lots 401m2 to 900m2 (3.1 EP/EDC) and lots less than 400m2 (2.5 EP/EDC).

An Average Daily Consumption (AD) of 500L/person/d is specified in FNQROC (07/08) as the average of all dwellings (i.e. residential and non-residential). However, as advised by Cairns Regional Council a rate of 270 L/EP/d has been adopted for residential demands for this study to reflect the actual average demand for detached Class 1 residential property in Cairns in 2006/07. Both of these figures are in the absence of recycle water use and water efficiency measures being considered. Adopted Desired Standards of Service for Sewerage


Sewage Flows:

1 Average Dry Weather Flow (ADWF) 270L/EP/d

2 Design Flow (DF) or Peak Wet Weather Flow (PWWF)

Maximum of: 5 x ADWF or C1 x ADWF Where: C1 = 15x(EP)-0.1587

3 Peak Dry Weather Flow C2 x ADWF Where: C2 = 4.7x(EP)-0.105

Gravity Sewer Design:

4 Flow Equation Gravity Sewers – Manning’s Pressure Mains – Hazen Williams

5 Manning’s friction factor 'n' All gravity pipes 'n' = 0.013

6 Minimum Velocity at PWWF 0.6 m/s

7 Minimum Velocity at PDWF 0.3 m/s

8 Depth of Flow @ PWWF (proposed sewers) Depth of flow <= 75% of diameter

Sewage Pumping Station Design:

9 Pump Motor Drives Variable speed drives may be used when approved

10

Wet Well Storage Requirements (m3 between pump "start and "stop" levels) This applies to both fixed and variable speed pump stations (for a VFD it is the discharge of a single pump at 50 Hz speed)

= (0.9 x Single Pump Capacity)/N Where: Single pump capacity measured in L/s, N=10 starts per hour for <50 kW motor and; N= Manufacturers Spec. > 50 kW motor

11 Well diameter

Minimum internal well diameter 2100mm, internal well diameter may be increased in increments of 300mm depending upon considerations such as: a) Clearance around pumps and pipework. b) Depth of pump station, and

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c) Geotechnical conditions.

12 Single Pump Capacity Greater than: C1 x ADWF Where: C1 = 15x(EP)-0.1587

13 Total SPS Capacity 5 x ADWF or Design Flow

14 Duty Point

With static head corresponding to top water level and pipe friction factors as follows: Duty Point 1 – Single Pump Operation: C1 x ADWF (L/s) vs. Static Head + Friction Head (m) Duty Point 2 – Duty Pump operating in parallel with Standby Pump: 5 x ADWF (L/s) vs. Static Head + Friction Head (m)

15 Pump Selection

Select a pump that is capable of operating at both duty points and which operates within the range of the system resistance curves that are determined by the Conditions detailed below: Condition 1 – Normal Operating Condition lower limit system resistance curve: Static head corresponding to Top Water Level with rising main friction factors as follows: C = 120 (dia. < 300mm) C = 140 (dia. > 300mm) Condition 2 – Normal Operating Condition Upper limit system resistance curve: Static Head corresponding to Bottom Water Level with rising main friction factors as follows: C = 100 (dia.< 300mm)

16 Top Water Level Must be set 300mm below invert level of inlet sewer.

17 Bottom Water Level

a) For fixed speed pumps: 100mm above minimum submergence level of pumps. b) For variable speed pumps: minimum of 100mm above top of motor casing

18 Operating Range (TWL-BWL) Generally this range should be between 1000mm and 2800mm.

19 Emergency Storage

6 hours at ADWF (local gravity catchment) May vary dependent on locating of overflow. Emergency storage may include gravity sewers, manholes and pump station wet well volume above TWL.

Rising Main Design:

20 Flow Equation Hazen Williams

21 Minimum Diameters 100 mm dia unless approved by Council

22 Hazen Williams friction factor 'C'

Lower limit system curve: 'C' = 120 pipes <= 300 mm dia; 'C' = 140 pipes > 300 mm dia Upper limit system curve: 'C' = 100 pipes <= 300 mm dia; 'C' = 120 pipes > 300 mm dia;

23 Minimum Velocity (single pump) 0.75 m/s

24 Design Velocity 1.0 to 1.5 m/s

25 Maximum Velocity (all pumps) 2.5 m/s

26 Interconnection of Rising Mains from Different Pump Stations Permitted only with approval of Council.

Recycled water demands shall be determined based on the predicted usage of drinking water and non-drinking water for the end uses nominated in accordance with FNQROC and Water Services Association of Australia (WSAA) and are required to be agreed with Cairns Regional Council.

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FNQROC will require future amendment to incorporate additional details on recycled water (e.g. if different peaking or demand factors are to apply). However, this is likely to be predominately based on and reference to current WSAA and DERM guidelines (i.e. WSA 02 – 2002 Water Supply Code of Australia and the Supplemental Dual Water Supply Systems, Queensland Water Recycling Guidelines, Water Supply and Sewerage Planning Guidelines). Fire fighting is proposed from the potable network in accordance with FNQROC. The WSAA code identifies operating the recycled water system at a lower pressure to reduce the risk of cross contamination from an unauthorised cross connection as an additional differentiation measure. However, this is not identified as a requirement unless specified by the Water Agency. The most recent Queensland Water Recycling Guidelines state that where the recycled water system does not have to provide the high flows or pressure required for fire fighting, the potable supply can be protected by the risk of backflow by operating the recycled water system at a lower pressure than the potable water system. Therefore, a lower differential pressure on the recycled water network is likely to be a requirement in Mount Peter. In providing the preliminary sizing of the recycled water network different peaking factors have been analysed. In determining an indicative recycled water network a peaking factor higher than currently specified for potable water has been assumed based on the residential multi family land use category for recycled water developed by Gold Coast City Council. Appropriate peaking factors will need to be agreed with Cairns Regional Council.

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2.3 FLOW ASSESSMENT

2.3.1 BASE CASE

The tables below provide a summary of the projected water supply demand and sewerage loads associated with the proposed development based on the Equivalent Population and Desired Standards of Service outlined in Section 2.2. Further potential reductions in per capita potable water consumption may be achieved through the water savings targets and efficiency mandatory under the Queensland Development Code. Section 2.3.2 provides an assessment of Integrated Water Cycle Management Demands, which considers the impact of water conservation measures and potable water substitution scenarios. Estimated Development Total Water Demand – Base Case 270L/EP/d

Land use EP AD MDMM MD MH

(L/s) (L/s) (L/s) (ML/d) (L/s)

Residential 51,755 162 243 365 31.4 728

Non-residential 5,191 16 24 37 3.2 73

Public Open Space 1,000 3 5 7 0.6 14

Subtotal 57,946 181 272 407 35.2 815

Small area of the North East Industrial

1,350 4 6 9 0.8 19

Total 59,296 185 278 417 36.0 834

*Total Water Demand to be supplied by a combination of potable and non-potable water sources. Estimated Development Sewage Flows – Base Case 270/EP/d

Land use EP ADWF C1 Flow PWWF ADWF

(L/s) (L/s) (L/s) (ML/d)

Residential 51,755 162 433 809 14.0

Non-residential 5,191 16 63 81 1.4

Public Open Space

Subtotal 57,103 178 497 892 15.4

Small area of the North East Industrial 1,350 4 6 9 0.8

Total 58,296 182 502 899 16.2

Where: C1 = 15x(EP)-0.1587 Based on tables above and recycled water outlined in Section 2.3.2 approximately 45% of the 15.4 ML/d ADWF flow will be available for recycled water to the industrial area to the north east or will require disposal and/or is available for irrigation/agriculture.

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2.3.2 INTEGRATED WATER CYCLE MANAGEMENT DEMANDS

Integrated water cycle management is a concept which seeks to promote a whole of water cycle planning approach, from source through to the use and disposal, or alternatively to treatment and reuse, forming a continual cycle. As part of the integrated water cycle management approach, three basic scenarios have been considered for Mount Peter which include water conservation and potable water substitution measures. On a development level, potable water substitution measures could be adopted for the irrigation of public open space areas, to achieve potable water savings and increase reuse. Available measures include recycled water, stormwater harvesting, dual function detention basin (lakes) and/or groundwater harvesting. On a household level, a reduction in per capita water consumption shall be achieved through mandatory compliance with the Queensland Development Code. Water efficiency measures covered under MP4.1 Sustainable Buildings include:

• Shower roses;

• Pressure management;

• Dual Flush Toilets; and

• Efficient Hot Water Systems. Water saving target measures covered under MP4.2 Water Saving Targets include:

• Rainwater Tanks; or

• Greywater; or

• Alternative Water Substitution method (e.g. Recycled Water, Stormwater harvesting, dual function detention basin (lakes) and/or groundwater harvesting), or

• Combinations of above. Recycled water has been advised as mandatory including the provision of a supply to the north east industrial area. The following internal water balance for a typical residential household has been assumed in this study.

Water Use Proportion of Demand (%)

Demand (L/EP/d)

Kitchen 11% 30

Bathroom 19% 51

Laundry 15% 41

Toilet 15% 41

Outdoor 40% 108

Total 100% 270

Three basic scenarios were considered which have potable water substitution implications and these are outlined in the following table.

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Option Household Fixtures (potable)

Household fixtures (non-potable)

Public Open Space

Base Case Incorporates Water Efficiency required in the QDC

Rainwater Tanks Potable

Scenario 1 Incorporates Water Efficiency required in the QDC

Rainwater Tanks Stormwater / Groundwater harvesting

Scenario 2 Incorporates Water Efficiency required in the QDC

Recycled Water Recycled Water

The scenarios include potable water substitution within households using rainwater tanks or dual reticulation recycled water respectively. As shown below, the permissible end uses for rainwater and recycled water class A+ are similar. For the purpose of this initial study, it has been assumed that potable substitution would apply to toilet flushing and outdoor uses, which is equivalent to approximately 55% of household demand subject to agreement with Cairns Regional Council. Permissible End Uses for Rainwater and Recycled Water Class A+

Source Recycled Water Class A+ Rainwater

Guidelines Water Quality Guidelines for Recycled Water Schemes, Draft June 2008

Queensland Development Code, April 2008

Suitable Uses

Toilet flushing Toilet flushing

Washing machine cold water taps Washing machine cold water taps External uses such as gardening, irrigation, ponds and outdoor cleaning

External uses such as gardening, irrigation, ponds and outdoor cleaning

- Filling swimming pools

- Other fixtures as specified by the local government in a local planning instrument

An indicative assessment on how each of these scenarios would impact on the base case flow assessment and associated infrastructure sizing is summarised below:

• Base Case and Scenario 1: Rainwater tanks would reduce the average annual residential potable water demand component by approximately 55%. However, the water supply infrastructure sizing would be unchanged from the base case, as it would need to be sized to deliver peak flow during prolonged dry periods when rainwater tanks are empty and stormwater is unavailable.

• Scenario 2: Dual reticulation recycled water would reduce the average annual residential potable water demand component by approximately 55%. The potable water supply infrastructure could be down sized from the base case, and a second dual reticulation network would be required. The volume of surplus treated effluent requiring disposal would be reduced from approximately 15.4ML/d to 6.9ML/d less potential reuse in the north east industrial area. However, the potable water infrastructure constructed will

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need to meet the desired standards of service in the interim until recycled water is made available.

2.4 METHODOLOGY

The methodology adopted for this preliminary water supply and sewerage infrastructure assessment is based on a desktop review of regional strategies published by State Agencies and analysis of available GIS datasets and CRC Planning Reports.

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3 OPPORTUNITIES/CONSTRAINTS

3.1 WATER SUPPLY

The following opportunities and constraints have been identified for Mount Peter in relation to water supply:

Opportunities

• Cairns Regional Council has advised that the development could be supplied through a future connection(s) to the existing 800mm diameter trunk main which runs along the eastern site boundary between Edmonton and Gordonvale. A direct connection to Mount Peter is not desirable as the main acts as a bulk trunk main supplying other surrounding reservoirs. Therefore, any connection from the 800m diameter main will need to be a dedicated trunk main supplying only the proposed local reservoirs to service the Mount Peter MPA. The potential exists to use the existing 400mm diameter main to provide a direct connection into the initial stages of development. Further information and investigation (i.e. model analysis) is required to confirm the condition and capacity of the external network during Master Planning. In discussions with Cairns Regional Council the existing Draper Road reservoir has been identified to have spare capacity to service the initial stages of development. However, a new main on Peterson Road and storage at Coombak Close may be required for the northern area and will be confirmed during Master Planning. There is a potential opportunity to recommission the existing Coombak Close Reservoir to service the initial development and to defer the timing of future reservoir(s).

• Local storage capacity will be needed to service the development. The higher elevation areas within Mount Peter (around 100m AHD) provide opportunity to site future storage reservoirs. Council have specifically identified three sites for the location of future reservoirs, this includes a potential water treatment plant site for the “Behana-Mulgrave WTP”. It is assumed that alternative sites could also be investigated and considered as required during Master Planning.

• The Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) has been adopted by Cairns Regional Council. This report recommends two new future water sources, the Barron River Water Scheme and the Mulgrave River Aquifer be developed, starting with Stage 1 of the Mulgrave River Aquifer. The development of the Mulgrave River Aquifer as recommended in the report will require a future Behana-Mulgrave water treatment plant as indicated by Cairns Regional Council to be located in the southern end of the Mount Peter MPA to support development in the area.. This report also identifies a trunk main through Mount Peter. The alignment of which will need to be considered and incorporated during Master Planning and design.

Constraints

• High level storage or booster pump station(s) are likely to be required to supply higher elevation areas (i.e. above approximately 65m AHD). Additionally, pressure management is likely to be required to service areas below approximately 40m AHD. These factors would increase the cost of servicing these areas. However, this would not restrict or constrain development.

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• The Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) that identifies and makes recommendations on the future water sources required to support growth in Cairns City and the greater Cairns area including Mount Peter has recently adopted by Cairns Regional Council. The condition and capacity of the existing and future external trunk main network under various different potential operational philosophies with the addition of the new water supplies will be confirmed during Master Planning and will be updated as required for the latest forecast growth rates for the Mount Peter MPA. The capacity in the interim/short term to service the Mount Peter MPA incorporating the timing of Stage 1 of the Mulgrave River Aquifer will also be confirmed during Master Planning. However, it should be noted the Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) has not identified any constraints and confirmation of the suitability of the trunk main network proposed by current planning is expected.

3.2 WASTEWATER

The following opportunities and constraints have been identified for Mount Peter in relation to wastewater:

Opportunities

• Flow from Mount Peter can be directed to the existing wastewater treatment plants at Edmonton and Gordonvale, in the interim. The Edmonton Gordonvale Sewerage Planning Network Reserve Capacity for Mount Peter development (Arup, 28 July 2009) and the Edmonton and Gordonvale Sewerage Planning Report (Arup, February 2010) indicates there is spare capacity in the Gordonvale sewerage network up to 1,000 EP. This report also indicates that there is an opportunity in the existing Edmonton sewerage network to accept load from the Mount Peter MPA in the interim at ED1 pump station and rising main or further upstream in the gravity network depending on an augmentation scheduled by Cairns Regional Council at ED1 and forecast augmentation required of the gravity network.

• Given the scale of the proposed development and need to provide recycled water, a new wastewater and recycled water treatment plant in proximity to the development area is proposed based on the Mount Peter MPA to Edmonton WWTP Sewerage Infrastructure Investigation (Cardno, June 2009) subject to obtaining the necessary regulatory approvals.

• The new treatment plant is proposed to supply recycled water for reuse within Mount Peter including the north east industrial and there is an opportunity to also supply it for agricultural irrigation.

• The natural contours across the site appear generally suitable for a gravity based collection system, with a limited number of pumping stations.

• Current technology will allow the future sewerage network to be designed to minimise stormwater infiltration, groundwater intrusion and sewer overflows.

Constraints

• The future wastewater strategy will need to allow for the sustainable management and reuse of treated effluent generated from the development. Recycled water infrastructure is mandatory within Mount Peter. However, additional recycling opportunities (e.g. agricultural, additional land for irrigation) shall need to be considered where possible as obtaining a licence

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for discharge to environmentally sensitive waterways is likely to be a limiting factor in the future and would not meet key environmental objectives.

• The potential location of key trunk sewers is along natural drainage paths and creek lines, and environmental and construction issues could present constraints that would need to be addressed in the detailed planning and design phases.

• No site has been identified or acquired for the option of a local Wastewater/Recycled Water Treatment Plant near Mount Peter including land for any excess effluent disposal.

3.3 WATER CYCLE MANAGEMENT

The following opportunities and constraints have been identified for Mount Peter in relation to water cycle management:

Opportunities

• The Greenfield site provides an opportunity to implement total water cycle management, which shall promote water conservation and potable water substitution measures. The use of recycled water (dual reticulation) including providing a supply to the north east industrial area has been identified as mandatory.

• In addition, potential options to use treated greywater, harvest stormwater runoff or groundwater shall also be considered as part of an overall water cycle management strategy.

Constraints

• The suitability of options shall be assessed against local climatic factors and the urban setting. In addition, consideration shall be given to scale (i.e. local, source versus regional options) issues.

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4 ISSUES

Water supply and sewerage options shall be developed with specific consideration of the following issues:

• Draft Regional Water Supply Strategy

The Draft Strategy provides the framework, information and guidance for the management of water supply issues in the region over the next 50 years. Information and actions identified in the strategy will be used when considering statutory regional planning and water resource planning in the area.

• Total Water Cycle Management

As set out in the FNQ Regional Plan water is a valuable and finite regional resource that needs to be managed on a total water cycle basis.

Strategies to implement Total Water Cycle Management will be developed specifically for the Mount Peter MPA in collaboration with Cairns Regional Council, to suit the local environment and to reflect the outcomes of regional water management initiatives.

Demand management measures shall be incorporated into an overall water cycle management strategy.

• Water Sensitive Urban Design

As part of a holistic water cycle management approach, best practice Water Sensitive Urban Design (WSUD) measures shall be implemented to suit the natural environment and meet water quality objectives set out in FNQ Regional Plan.

• Pressure and Leakage Control

The internal water supply network shall be designed with a target maximum operating pressure of approximately 60m in accordance with topography.

• Mandatory Water Savings Targets set by Queensland Development Code

Water savings targets and efficiency are mandatory under the Queensland Development Code (QDC).

Households in the Cairns Regional Council are required to achieve water savings of 44,000 litres per annum for new detached houses and 26,000 litres for other new Class 1 dwellings.

The key issues to be resolved are presented in the Action Plan in Section 6.2.

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5 DISCUSSION

5.1 WATER CONSERVATION

5.1.1 QUEENSLAND DEVELOPMENT CODE

Households are required to meet mandatory water savings targets set by the Queensland Development Code.

Households in the Cairns Regional Council are required to achieve water savings of 44,000 litres per annum for new detached houses and 26,000 litres for other new Class 1 dwellings.

On a household level, a reduction in per capita water use shall be achieved across Mount Peter through compliance with the Queensland Development Code and mandatory recycled water infrastructure in Mount Peter. Water efficiency measures covered under MP4.1 Sustainable Buildings include:

• Shower roses;

• Pressure management;

• Dual Flush Toilets; and

• Efficient Hot Water Systems. Water saving target measures covered under MP4.2 Water Saving Targets include:

• Rainwater Tanks; or

• Greywater; or

• Alternative Water Substitution method (e.g. Recycled Water, Stormwater harvesting, dual function detention basin (lakes) and/or groundwater harvesting), or

• Combinations of above.

5.2 POTABLE WATER SUBSTITUTION

Mandatory recycled water infrastructure in Mount Peter limits the opportunities for additional substitution at a whole of development level. However, the possibility of using treated greywater across the Mount Peter MPA can still be considered by individuals at a household level and potential options to harvest stormwater runoff or groundwater could also be considered for specific developments at the development application stage as part of an overall water cycle management strategy.

Careful consideration at the development application stage will be required to determine if the options are suitable given local climatic factors and urban setting. In addition, consideration will need to be given to scale (i.e. local, source versus regional options).

5.2.1 RECYCLED WATER

The Draft Regional Water Supply Strategy lists recycled water as a key opportunity for a new urban supply of non-potable water for Cairns. Recycled water infrastructure in Mount Peter including the provision of a supply to the north east industrial area is mandatory.

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Identified opportunities for recycling water include treated effluent primarily from the proposed centralised new Mount Peter wastewater treatment plant. However, there is also an opportunity to consider on-site treatment plant/s, sewer mining and on-site commercial and industrial reuse.

Effluent treatment in Cairns has traditionally been treated to a secondary standard (effluent to meet specified chemical and biological parameters) and is a combination of activated sludge and biological filter treatment processes.

A future new wastewater treatment plant near Mount Peter to produce recycled water is considered to be one of the most practical options. This would require the addition of additional treatment processes to meet recycled water quality standards.

It is proposed that limited recycled water would be stored on the treatment plant site and the rest pumped to Mount Peter through a trunk network with the addition of recycled water storage/s within Mount Peter. The design flow of this treatment process and trunk infrastructure will depend on the sewage generated and demand for recycled water to be determined during Master Planning. The quality of recycled water produced would also dictate the range of potential uses.

As outlined in the Water Quality Guidelines for Recycled Water Schemes (NRW, November 2008), the production of Class A+ recycled water will be required to enable a dual reticulation scheme in Mount Peter, to deliver recycled water to households for uses such as outdoors, the cold water supply to a washing machine and flushing toilets.

The water quality criteria for Class A+ recycled water is outlined in Schedule 3C of the Public Health Regulation 2005.

5.3 POTABLE WATER SUPPLY

The majority of Cairns' water comes from Copperlode Falls Dam (via an intake at Crystal Cascades) and Behana Creek. Many of the smaller rural communities within the Cairns Regional area are supplied from separate creek intakes. The capacity of the Copperlode Falls Dam (Lake Morris) is outlined below:

• Crystal Cascades Water Intake* (hydraulic capacity ~ 120ML/d)#

• Behana Creek Water Intake* (take authorised by license conditions – season and flow dependant. Maximum licensed extraction is 44ML/d; maximum hydraulic extraction achieved to date is 39ML/d)#

Existing sources have insufficient capacity to meet future regional demands.

5.3.1 WATER SUPPLY PROJECTS

The FNQ Regional Water Supply Strategy (currently in draft format) and Cairns Regional Council are developing a strategy to meet future water supply demands and accommodate the significant population growth anticipated for the region.

Key water supply projects identified by Cairns Regional Council include:

• Barron River Water Scheme, which will include a new water source, pipelines and a treatment plant; and

* Information provided by Cairns Regional Council (18/8/09) # Note – safe yield average day demand is 72ML/d

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• Mulgrave River Aquifer, which could be further developed for water supply purposes depending on the outcomes of engineering and environmental feasibility studies currently being undertaken by Council.

In addition, measures to reduce per capita demand shall be used to defer the timing of the new water supplies.

The Draft FNQ Regional Water Supply Strategy includes further details of alternative sources and potential contingency supplies for the Cairns Region. Information and actions identified in the strategy will be used when considering regional planning and water resource planning in the area.

A Council decision on the future water source(s) for Cairns to support growth including Mount Peter has been made (Council adopted the report on 15 April 2009) based on the completed Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) that recommends Mulgrave Aquifer Stages 1 and 2 followed by the Barron River Stage 1 depending on manageability of the environmental impacts of higher abstraction from the aquifer associated with Stage 2.

5.3.2 STORAGE

The Mount Peter MPA is located between the existing Edmonton and Gordonvale water supply areas. These areas are connected by parallel 800mm and 400mm diameter trunk mains which run along the eastern boundary of the Mount Peter MPA.

Local storage capacity will be needed to service the development. Further investigation is required during Master Planning to confirm the following:

• The existing storages located outside the study area, in the vicinity of Mount Peter (as shown on Figure 1), have spare capacity and capability to service any initial development stages particularly the Draper Road Reservoir and if a main along Petersen Road and storage at Coombak Close is required in the interim;

• Detailed staging of future storage capacity required within Mount Peter to match future population growth.

Council GIS data indicates that the Edmonton water supply network has a limited amount of local storage located in close proximity to Mount Peter, provided by a reservoir at Centenary High (2ML, TWL 131m), Plantation Reservoir (0.2ML, TWL 150m) and major reservoirs at Robert Road (30ML, TWL 90m) and Edmonton West (20ML, TWL 125m) within the Southern water supply area. There is also decommissioned 0.9ML Intermediate Level Reservoir (TWL 97.5m) at Coombak Close, which has been identified as a potential site for a new reservoir to service Mount Peter.

Similarly, the Gordonvale area has local storage in proximity to Mount Peter, provided by reservoirs at Dempsey St (two 0.18ML, TWL 110m) and Draper Road (20ML, TWL 92m).

Storage capacity of approximately 36ML will be required ultimately (based on equivalent population for water of 59,296EP).

The optimal location and level for future storage reservoirs will be determined through consideration of the existing network operation (model analysis) and consideration of the extent of developable land within the Mount Peter MPA during Master Planning. Council have identified 3 potential sites within Mount Peter, this includes a potential site for a WTP, as shown on Figure 1. It is assumed that alternative sites could also be investigated as required during Master Planning.

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High level storage or booster pump station(s) are likely to be required to supply the higher elevation areas, for example along the western and southern boundaries of the site, depending on the extent of developable land. The provision of additional emergency storage for these areas will also need to be considered. Typically emergency storages in residential areas are sized to include at least 2 hours of fire flow (15L/s) or greater depending on the outcome of a risk assessment undertaken by the service provider and in consultation with the Queensland Fire and Rescue Service (QFRS).

5.3.3 DISTRIBUTION

There are two parallel trunk mains of 800mm and 400mm diameter which run along the eastern boundary of the site, connecting the Edmonton and Gordonvale water supply areas. Cairns Regional Council has advised that the Mount Peter MPA will likely be supplied through the existing 800mm diameter trunk main, possibly at a future connection(s) near Maitland Road (refer to Figure 1). A direct connection to Mount Peter is not desirable as the main acts as a bulk trunk main supplying other surrounding reservoirs. Therefore, any connection from the 800m will need to be a dedicated trunk main supplying only the local reservoirs servicing the Mount Peter MPA. The potential exists to use the existing 400mm diameter main to provide a direct connection into the initial stages of development from Draper Road as discussed above.

An indicative internal trunk water supply layout based on a reduction in size to take account of recycled water is shown on Figure 1. However, further investigation (i.e. model analysis) is required to confirm the future infrastructure augmentations required to service the proposed ultimate development during Master Planning.

5.4 WASTEWATER

5.4.1 TREATMENT

A future sewage treatment and augmentation strategy commissioned by Cairns Regional Council for the Edmonton and Gordonvale catchment has produced the Edmonton and Gordonvale Sewerage Planning Report (Arup, February 2010).

There is an existing wastewater treatment plant located at Edmonton, north of the site that is proposed to be upgraded. The Cleaners Seas Report states that additional space is available at the site to allow further expansion.

There is also an existing wastewater treatment plant located at Gordonvale, south of the site. Council previously considered an upgrade of this plant in the future to meet projected urban growth within the catchment area.

Flow from the Mount Peter MPA is proposed to be directed to the existing wastewater treatment plants at Edmonton and Gordonvale (refer to Figure 3) in the interim using a proposed interim two interim pump stations and associated rising mains.

Given the scale of the proposed development and need to provide recycled water, the option to implement a new sewerage treatment plant in proximity to the development area is proposed based on the Mount Peter MPA to Edmonton WWTP Sewerage Infrastructure Investigation (Cardno, June 2009) subject to obtaining the necessary regulatory approvals.

Consideration will need to be given to the management of wastewater/treated effluent generated from the development at the proposed new plant at Mount Peter

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i.e. wet weather storage and land for irrigation above that reused. The management of treated effluent will also need to consider recycling opportunities where possible to nearby farmland and agriculture.

It should be noted that there is likely to be a reduction in wastewater generation at a household level due to the installation of water efficient appliances and compliance with the mandatory targets set by the Queensland Development Code. As a result, the volume of wastewater requiring disposal and/or reuse is expected to also be reduced.

5.4.2 SEWERAGE COLLECTION

The natural contours across the site appear generally suitable for a gravity based collection system. The proposed location of key trunk sewers is shown on Figure 3, based on natural drainage paths and creek lines and an assumed grade depending on survey and finished surface levels to be established during Master Planning. It should be noted that environmental and construction issues would need to be addressed in the detailed planning and design phases.

It is likely that some local pump stations will also be required to service the proposed development, and limit the depth of major trunk sewers. The number and optimal location of these pump stations shall be determined based on final ground levels and the developable area during Master Planning.

The majority of the site drains towards the east and the intersection of the Bruce Hwy and Harris Road. The natural site for any new Mount Peter treatment plant is as near as possible to this location, as indicated on Figure 3.

The Edmonton Gordonvale Sewerage Planning Network Reserve Capacity for Mount Peter development (Arup, 28 July 2009) and the Edmonton and Gordonvale Sewerage Planning Report (Arup, February 2010) indicates there is spare capacity in the Gordonvale sewerage network up to 1,000 EP. This report also indicates that there is an opportunity in the existing Edmonton sewerage network to accept load from the Mount Peter MPA in the interim at the ED1 pump station and rising main or further upstream in the gravity network depending on an augmentation scheduled by Cairns Regional Council at ED1 and forecast augmentation required of the gravity network.

As outlined in the Assumptions report, the future sewerage network shall be designed to minimise stormwater infiltration, groundwater intrusion and sewer overflows.

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6 SUMMARY RECOMMENDATIONS

6.1 SUMMARY

This report considers the existing water supply and sewerage trunk infrastructure available within the vicinity of the Mount Peter MPA. External and internal infrastructure required to maintain Desired Standards of Service following the inclusion of the proposed development will require confirmation during Master Planning.

An initial estimate of the equivalent population for water and sewerage demands for the development is 58,103 to 77,138 EP excluding the industrial area to the north east. The current estimate is 57,946 EP and is composed of 51,755 EP for the residential component based on 18,484 dwellings at 2.8 EP per ET for water and sewerage in accordance with CRC and FNQROC and an allowance of 10% for the non-residential component (equivalent to approximately 32EP/ha) and a further 1,000 EP for open space/community. The industrial area to the north east with the exception of the parcel fronting Deppeler Road (Lot 3 SP 105994) is proposed to be serviced by existing and proposed water supply and sewerage infrastructure on Thomson Road and in the Edmonton area. Therefore, planning and the future PIP for this land will be prepared and considered by Council separately to Mount Peter and has been excluded from this analysis. A small area of the north east industrial area allowed for in Mount Peter and is an additional approximate 1,350EP (i.e. 43.4 ha at approximately 32EP/ha). Therefore, the total population for Mount Peter is 59,296EP.

The industrial area to the north east is approximately 251ha and at 32 EP per ha is equivalent to approximately 8,043EP. Recycled water provision to the industrial land to the north east will depend on final end use which is currently unknown. Therefore, it is not possible to forecast and plan the infrastructure requirements. However, a proposed supply of recycled water to the whole of the north east area has been allowed through the provision of nominal trunk mains to the area that will need to be addressed during Master Planning or through individual infrastructure agreements as re-use opportunities are defined. The above is based on developable area and density assumptions which are subject to change and shall be reviewed during Master Planning.

As requested by Cairns Regional Council, a water demand rate of 270 L/EP/d for residential properties has been adopted for this study to reflect the actual average demand for a residential property in 2006/07, rather than the 500L/person/d gross consumption for residential and non-residential users as specified in FNQROC (07/08). A design sewage flow rate of 270L/EP/d has been adopted for this study as specified in FNQROC and confirmed by Cairns Regional Council.

The projected flow rates for the proposed development (i.e. excluding the industrial area to the north east) are as follows:

• Total Water Demand up to 16ML/d (Average day) to be supplied by a combination of potable and non-potable water sources;

• Sewage Load up to 15.7ML/d (Average Dry Weather Flow)

Further potential reductions in per capita water consumption and sewage flow rates may be achieved through the water savings targets and efficiency mandatory under the Queensland Development Code.

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Integrated Water Cycle Management Under an integrated water cycle management approach, scenarios shall be considered which include potable water substitution measures (i.e. recycled water) during Master Planning. A future new wastewater treatment plant at Mount Peter to produce recycled water is considered to be one of the most practical options to supply Mount Peter with recycled water and the preferred site shall be confirmed in collaboration with Cairns Regional Council during Master Planning.

Mandatory recycled water infrastructure in Mount Peter including the north east industrial area limits the opportunities for additional substitution at a whole of development level. However, the possibility of using treated greywater across the Mount Peter MPA can still be considered by individuals at a household level and potential options to harvest stormwater runoff or groundwater could also be considered for specific developments at the development application stage as part of an overall water cycle management strategy. The suitability of options shall be assessed against local climatic factors and the urban setting. In addition, consideration shall be given to scale (i.e. local, source versus regional options) issues.

Potable Water Supply

Key existing water sources currently supplying Cairns include Copperlode Falls Dam, and intakes at Crystal Cascades and Behana Creek. Existing sources have insufficient capacity to meet future demands.

The Draft Regional Water Supply Strategy and Cairns Regional Council are developing a future strategy for the region. Key water supply projects currently under investigation by Cairns Regional Council include the Barron River Water Scheme and the Mulgrave River Aquifer. In addition, measures to reduce per capita demand shall be used to defer the timing of these new water supplies.

A Council decision on the future water source(s) for Cairns to support growth including Mount Peter has been made (Council adopted the report on 15 April 2009) based on the completed Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) that recommends Mulgrave Aquifer Stages 1 and 2 followed by the Barron River Stage 1 depending on manageability of the environmental impacts of higher abstraction from the aquifer associated with Stage 2.

Potable Water Supply Infrastructure Cairns Regional Council have advised that the development could be supplied through a future connection(s) to the existing 800mm diameter trunk main which runs along the eastern site boundary between the Edmonton and Gordonvale. The potential also exists to use the existing Draper Road Reservoir and the existing 400mm diameter main to provide a direct connection into the initial stages of development particularly to the southern areas. The northern areas may require a new main along Petersen Road and storage at Coombak Close either through interim recommissioning of the existing reservoir or a new reservoir. Further investigation (model analysis) is required to confirm the future external infrastructure augmentations to service the proposed development during Master Planning.

Local storage capacity will be needed to service the development. High level storage or booster pump station(s) are likely to be required to supply higher elevation areas.

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Wastewater Treatment Flow from Mount Peter is proposed to be directed to the existing wastewater treatment plants at Edmonton and Gordonvale in the interim.

Given the scale of the proposed development and need to provide recycled water, a new wastewater and recycled water treatment plant in proximity to the development area is proposed based on the Mount Peter MPA to Edmonton WWTP Sewerage Infrastructure Investigation (Cardno, June 2009) subject to obtaining the necessary regulatory approvals.

Consideration will need to be given to the management of wastewater/treated effluent generated from the development recognising the FNQ Regional Plan reuse targets and requirement to eliminate wastewater point source discharges during Master Planning. This will need to consider recycling opportunities where possible to nearby farmland and agriculture.

Sewerage Infrastructure The natural contours across the site appear generally suitable for a gravity based collection system. The proposed location of key trunk sewers is shown on Figure 3, based along natural drainage paths and creek lines. Environmental and construction issues will need to be addressed in the detailed planning and design phases.

It is likely that pump stations will be required. The number and optimal location of these pump stations shall be determined based on survey and final ground levels and the developable area during Master Planning.

The future sewerage network shall be designed to minimise stormwater infiltration, groundwater intrusion and sewer overflows.

The Edmonton Gordonvale Sewerage Planning Network Reserve Capacity for Mount Peter development (Arup, 28 July 2009) and the Edmonton and Gordonvale Sewerage Planning Report (Arup, February 2010) indicates there is spare capacity in the Gordonvale sewerage network up to 1,000 EP. This report also indicates that there is an opportunity in the existing Edmonton sewerage network to accept load from the Mount Peter MPA in the interim at the ED1 pump station and rising main or further upstream in the gravity network depending on an augmentation scheduled by Cairns Regional Council at ED1 and forecast augmentation required of the gravity network.

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6.2 ACTION PLAN

No. Item Responsibility Timeline Cost

1 Council has decided on the future water source(s) for Cairns to support growth including Mount Peter based on the completed Draft Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) that recommends Mulgrave Aquifer Stages 1 and 2 followed by the Barron River Stage 1 depending on manageability of the environmental impacts of higher abstraction from the aquifer associated with Stage 2.

Council Decision Complete – Council has adopted the Overall Water Supply Strategy Planning Report

Study Previously funded

2 Following on from the outcome of 1.

Confirm the future external trunk main infrastructure augmentations to support the Mount Peter MPA based on Council’s current planning, PIP and the incorporation of the future water sources adopted by Council in the Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009). Specifically, confirm the future external trunk main augmentations in Council’s existing and future hydraulic models under various operational philosophies and update as required with the latest forecast growth rates for the Mount Peter MPA. The capacity in the interim/short term to service Mount Peter incorporating the timing of Stage 1 of the Mulgrave River Aquifer will also be confirmed during Master Planning. However, it should be noted Council’s current planning and the Overall Water Supply Strategy for Cairns Planning Report (Cairns Regional Council, March 2009) has not identified any constraints and confirmation of the suitability of the trunk mains network proposed by current planning is expected.

Council Master Planning Stage

TBA

3 There are a few minor additional comments from Cairns Regional Council on the Edmonton and Gordonvale Sewerage Planning Study study(*) to be addressed before it is finalised. However, these have not been identified as affecting the assumptions and outcomes incorporated in this report

Council Revised report completed February 2010. Final - TBA.

Study previously funded

4 Finalise planning decision on location of ultimate wastewater treatment capacity for Mount Peter subject to obtaining the necessary relevant approvals.

Council Master Plan Stage

-

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No. Item Responsibility Timeline Cost

5 Pending outcomes of above and confirmation of developable area and yields determine key internal water, sewerage and recycled water infrastructure.

Council Master Planning Stage

TBA

TBA – To be advised


APPENDIX A

SUPPORTING INFORMATION

Figure 1 Indicative Water Supply Layout

Figure 2 Indicative Recycled Water ayout

Figure 3 Indicative Sewerage Layout

mount peter structure plan part 5 - technical report … · in order to assess water and sewerage...

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