water supply & sewerage infrastructure for yaroomba beach

Yaroomba Beach Water Supply & Sewerage Infrastructure Assessment

3 May 2017

REVISION 6

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Water Supply & Sewerage Infrastructure for Yaroomba Beach | i

TABLE OF CONTENTS

1 INTRODUCTION ......................................................................................................................2

2 DESIGN CRITERIA ....................................................................................................................3 2.1 Water Supply ............................................................................................................................. 3

2.1.1 Demand and Peaking Factors ............................................................................................... 3 2.1.2 Storage ................................................................................................................................. 3 2.1.3 Fire Fighting .......................................................................................................................... 3 2.1.4 Residual Pressures ................................................................................................................ 4 2.1.5 Hazen-Williams Coefficient & Velocity ................................................................................. 4

2.2 Sewerage.................................................................................................................................... 4 2.2.1 Gravity Sewer ....................................................................................................................... 4 2.2.2 Pumping Stations .................................................................................................................. 4 2.2.3 Rising Mains .......................................................................................................................... 4

3 ESTIMATED POPULATION AND FLOW ......................................................................................5 3.1 Equivalent Population ................................................................................................................ 5 3.2 Staging Plan ................................................................................................................................ 7 3.3 Projected Water Demands and Sewage Loads .......................................................................... 8 3.4 Outdoor Water Use.................................................................................................................... 9 3.5 Comparison to Previous Development Proposal ....................................................................... 9

4 INTEGRATED WATER CYCLE MANAGEMENT .......................................................................... 10 4.1 Demand Management .............................................................................................................10 4.2 Alternative Water Sources .......................................................................................................10

5 WATER SUPPLY INFRASTRUCTURE ........................................................................................ 12 5.1 Bulk Water Source Capacity .....................................................................................................12 5.2 Bulk Water Network Capacity ..................................................................................................12 5.3 Storage Requirements .............................................................................................................12 5.4 Trunk Network .........................................................................................................................14 5.5 Connection & Metering ...........................................................................................................14 5.6 Reticulation Network ...............................................................................................................14

6 SEWERAGE INFRASTRUCTURE ............................................................................................... 15 6.1 Sewage Treatment Strategy.....................................................................................................15 6.2 Trunk Network .........................................................................................................................15 6.3 Reticulation Network ...............................................................................................................16 6.4 Recycled Water ........................................................................................................................16

7 CONCLUSIONS ...................................................................................................................... 18

Appendix A Masterplan Layout ................................................................................................ 20

Appendix B Previously Proposed Augmentations (2013) ........................................................... 21

DOCUMENT / REPORT CONTROL FORM ....................................................................................... 22

Water Supply & Sewerage Infrastructure for Yaroomba Beach | 2

1 INTRODUCTION

SMEC Australia has been engaged by SH Coolum Pty Ltd to undertake civil engineering services for the proposed re-visioning of the Coolum Beachside Precinct, now called Yaroomba Beach, which is located on the eastern side of the David Low Way in Yaroomba.

The historical plans for the site developed in 2005 included a gated housing and apartment residential subdivision. The current plan for the site is a revised concept to create a coastal village to promote public access and a change in the use and density to accommodate a 5-star international resort, public amenities and a range of residential products.

This report has been developed to document the outcomes of a Water Supply and Sewerage Assessment undertaken as part of the broader project for the proposed new development. The objectives of this assessment are to identify opportunities for integrated water cycle management and to assess likely water and sewerage trunk infrastructure requirements.


2 DESIGN CRITERIA

The Design Criteria and Desired Standards of Service (DSS) adopted for this study are the South East Queensland Water Supply and Sewerage Design and Construction Code (SEQ Code) – Design Criteria, July 2013. Key criteria are detailed in the sections below for the Unitywater service area.

2.1 Water Supply

2.1.1 Demand and Peaking Factors

Average Day Consumption (AD) = 230 L/EP/day

Non-revenue Water (NRW) = 30 L/EP/d

Residential:

Mean Day Maximum Month/Average Day (MDMM/AD) = 1.5

Peak Day/ Average Day (PD/AD) = 2

Peak Hour/ Peak Day (PH/PD) = 2

Peak Hour/ Average Day (PH/AD) = 4

High Density Residential:

Mean Day Maximum Month/Average Day (MDMM/AD) = 1.5

Peak Day/ Average Day (PD/AD) = 2

Peak Hour/ Peak Day (PH/PD) = 1.75

Peak Hour/ Average Day (PH/AD) = 3.5

2.1.2 Storage

Ground Level Reservoir = 3 x (PD – MDMM) + Emergency Storage

(Emergency Storage - Greater of 4hrs at MDMM or 0.5 ML)

Elevated Reservoir = 6 x (PH – 1/12 MDMM)+150kL fire storage

(PH is in kL/h, MDMM is in kL/d and reservoir storage is in kL)

In supply zones where 8xPH is less than or equal to MDMM the following equation is used: (2 x PH) + 150 kL fire storage.

2.1.3 Fire Fighting

Fire Flow Detached Res (<= 3 storeys): 15 L/s for 2hrs with background Demand

Multi story Res (> 3 storeys): 30 L/s for 4hrs with background Demand

Commercial/Industrial: 30 L/s for 4hrs with background Demand

Single fire event only

Where the background demand for Residential Areas (Detached/ Multi storey) is the Highest of 2/3 PH or AD, and for Commercial / Industrial is PH demand (between 10am and 4pm).


2.1.4 Residual Pressures

Maximum pressure = 55 m

Minimum pressure = 22 m

Minimum pressure firefighting = 12 m

2.1.5 Hazen-Williams Coefficient & Velocity

Hazen Williams Friction Factors for internal diameter as follows:

<=150 C=100

>150 -300mm, C=110

Additional Design Criteria for Head Loss rate limits (PH) as follows:

DN<=150, 5m/km

DN>=200, 3m/km

Maximum allowable velocity: 2.5m/s

2.2 Sewerage

2.2.1 Gravity Sewer

Per Capita Flow:

Average Dry Weather Flow (ADWF) = 200 L/EP/d

For RIGS1

Peaking Factor:

Peak Wet Weather Flow (PWWF) = 5 x ADWF

Friction Coefficient – Manning’s ‘n’ =0.0128

2.2.2 Pumping Stations

Minimum Operational Volume of Wet Well (m3) = (0.9 x Pump Rate)/N

Where pump rate is in L/s

N=12 for motors<100kw

N=8 for 100-200kw

N=5 of motors >200kw

Single Pump Capacity = C1 x ADWF

Where C1 = 15 x (EP) – 0.1587

Total Pump Station Capacity = 5 x ADWF

2.2.3 Rising Mains

Preferred Velocity: 1.0 – 1.5 m/s

1 RIGS: Reduced Infiltration Gravity Sewers


3 ESTIMATED POPULATION AND FLOW

3.1 Equivalent Population

Various methods have been used to calculate the demand, with the demand assumptions summarised in Table 1. Rates used in other SEQ tourism areas2 have been considered in this assessment as they provide a further breakdown for hotel rooms and multi-unit dwellings not currently covered by the Unitywater guidelines. The equivalent population associated with the full proposed development has been calculated in Table 2 to allow assessment of the impact of the development on the surrounding water supply and sewerage networks.

Table 1 – Demand Assumptions, for three calculation methods

Type of Dwelling Assumed Development

Type Unit EPW/Unit EPS/Unit

Method 1: Unitywater Schedule of Works3

Single Dwelling Detached Residential Dwelling ET 2.7 2.7

Hotel Rooms Serviced Apartments Apartments

Attached Residential Dwelling ET 1.8 2.7

Retail (Internal/External) Commercial (Retail/Hotel)

Centres 100 m2 GFA 1.32 1.54

Community Space (Internal/External)

Community 100 m2 GFA 3.13 3.13

Method 2: Unitywater proposed Schedule of Works changing Hotels4, still subject to review

As per Method 1, except hotel

Hotel Rooms Hotel 100 m2 GFA 2.4 2.4*

Method 3: Alternative SEQ Tourism Rates2 ET/Unit EP/Unit**

Single Dwelling Detached Dwelling dwelling 1 2.7

Hotel Rooms Motel / Hotel bedroom 0.6 1.62

Serviced Apartments Apartments

Multi Unit Dwelling 1 bedroom Multi Unit Dwelling 2 bedroom

dwelling 0.47 0.63

1.27 1.70

Retail (Internal/External) Retail 100 m2 GFA 0.6 1.62

Commercial (Retail/Hotel) Commercial (other) 100 m2 GFA 0.6 1.62

Community Space (Internal/External)

Conference / meeting venue 100 m2 GFA 1.6 4.32

*Assumed to be the same as EPW ** EP/ET = 2.7 for Unitywater as per SEQ Code Design Criteria, Appendix A

2 SEQ Code Design Criteria – Table A2 Typical Water and Wastewater Supply Demand Generation Rates for Development Types (Gold Coast Area), Version 1.0 – 1 July 2013 3 Unitywater Schedule of Works, Version 1.0, 25 June 2014 – Section 1.3 4 As supplied by Unitywater 20/02/2017


Table 2 – Estimated Equivalent Full Development Population, for three calculation methods

Type of Dwelling Qty Unit

Method 1: Unitywater

Method 2: Unitywater

Proposed, with Hotel adjusted

Method 3: Alternative

SEQ Tourism Rates

EPW EPS EPW EPS EP

(EPW & EPS)

Hotel

Rooms 220

(16,202) Bedroom

(GFA) 396 594 389 389 356

Dual Key Serviced Apartments* (42 x 1 bed, 28 x 2 bed)

70 dwelling

392 589 293 388 335

Serviced Apartments (35 x 1 bed, 43 x 2 bed)

78 dwelling

Sub Total Hotel 368 - 788 1,183 682 777 691

Residential

Apartment (2 bed) 757 dwelling 1,363 2,044 1,363 2,044 1,288

Single Dwelling 102 dwelling 275 275 275 275 275

Sub Total Residential 859 - 1,638 2,319 1,638 2,319 1,563

Retail / Commercial 3,549 GFA 47 55 47 55 58

Community 356 GFA 11 11 11 11 15

TOTAL 2,484 3,568 2,378 3,162 2,327

* Note for the dual key apartments the following has been assumed for the calculation of loads: 1-bedroom apartment = 2 x hotel rooms 2-bedroom apartment = 1 x hotel room + 1 x 1 bedroom apartment

There is a significant variance between the EP loads calculated using the Alternative SEQ Tourism and Unitywater demand rates. Method 2: Unitywater Proposed, will be adopted in this report as it provides a conservative estimate, while still recognising the difference between a hotel and a detached dwelling. The reduced load using Method 3: Alternative SEQ Tourism Rates, should also be considered for this development given the adoption of water saving initiatives discussed in Section 4.

It should also be noted that some of the GFA included in the Retail / Commercial use is located within the hotel, and therefore the load may already be covered by the hotel load calculation. However, at this stage, for a conservative approach, it has been included separately.


3.2 Staging Plan

The proposed development is to be implemented in five precinct stages, as shown in Appendix A. The configuration of the precincts is outlined in Table 3. This staging plan has been factored into the assessment of water and sewerage infrastructure requirements.

Table 3 – Staging Plan (Using Method 2: Unitywater Proposed calculation method)

Precinct Type of Dwelling Qty EPW EPS

1

Hotel Rooms 220

(16,202 m2 GFA) 389 389

Serviced Apartments 148 293 388

Single Dwellings 16 43 43

Retail / Commercial / Community 3,905 m2 GFA 58 66

SUB-TOTAL 783 886

2

Apartments (2 bed) 139 250 375

Single Dwelling 10 27 27

SUB-TOTAL 277 402

3



SUB-TOTAL 360 497

4



SUB-TOTAL 385 545

5



SUB-TOTAL 572 832

TOTAL 2,378 3,162


Based on the staging plan in Table 3, a cumulative growth curve is illustrated in Figure 1.

Figure 1 Projected Growth Curve

3.3 Projected Water Demands and Sewage Loads

The projected water supply demand and sewage loads for the proposed development site have been assessed based on the estimate equivalent population and the design criteria as outlined in Section 2. These are outlined in Table 4 and Table 5 respectively.

Table 4 – Projected Potable Water Demand (Using Method 2: Unitywater Proposed)

Precinct EPW AD* MDMM PD PH

L/s kL/day kL/day kL/day L/s

Hotel 682 2.1 177 256 334 7.5

Residential 1,638 4.9 426 614 803 18.0

Retail / Commercial / Community

58 0.2 15 22 28 0.6

Total 2,378 7.2 618 892 1,165 26

*including NRW

0

500

1,000

1,500

2,000

2,500

3,000

3,500

1 2 3 4 5

Esti

mat

ed

Po

pu

lati

on

(EP

)

Stage

Total EP Water Total EP Sewer

Water - Hotel & Serviced Apartments Sewer - Hotel & Serviced Apartments

Water - Retail / Community Sewer - Retail / Community

Water - Residential Sewer - Residential


Table 5 – Projected Sewage Loads (Using Method 2: Unitywater Proposed)

Precinct EPS ADWF PWWF

kL/d L/s kL/d L/s

Hotel 777 155 1.8 777 9

Residential 2,319 464 5.4 2,319 27

Retail / Commercial / Community

66 13 0.2 66 0.8

Total 3,162 632 7.3 3,162 37

3.4 Outdoor Water Use

The proposed development consists of large areas of open space that would require irrigation. These areas include a central Lake area, generous landscaped corridors and buffer strips along David Low Way.

The landscape architects have previously estimated peak irrigation demand would be in the order of 0.14 ML/d (based on irrigating 50% of the softscape). At this stage irrigation demand has been based on this estimated.

It is proposed that an alternative non-potable water source such as spear bores or rainwater harvesting be used for outdoor irrigation, supplemented by potable water only when necessary. Refer to Section 4.2.

3.5 Comparison to Historical Development Proposal

In 2005, a development proposal was assessed for the Yaroomba Beach site, as part of the Hyatt Coolum project. The proposal covered a larger area, with the area covered in this assessment known as the Beachside Precinct. Since this previous assessment, both the estimated population for the site and the applied DSS have changed, impacting on the water and sewerage infrastructure required to accommodate growth at the site.

Key changes and their impacts are outlined below:

The estimated population of the proposed development has increased since 2005

Unit water demands have reduced significantly since 2005

The estimated water demand for the site has increased since 2005

For the wider Coolum Area, the total projected water demand has reduced by around 40%, resulting in significant spare capacity in the existing water network

Unit sewage loads have reduced since 2005

The estimated sewage load for the site has increased since 2005.


4 INTEGRATED WATER CYCLE MANAGEMENT

4.1 Demand Management

The historical plans for the site were developed in 2005, since then unit water demands have significantly reduced, due to changed community behaviours around water conservation, the widespread introduction of water efficient appliances and improved system management. Therefore, opportunities to achieve significant water savings through targeted demand management strategies have also reduced.

Current average water usage across the Unitywater service area is reported to be lower than the design unit demand of 230L/EP/day.

It is possible that the development of Yaroomba Beach can maintain lower than average water consumption through strategies such as:

Native vegetation and drought tolerant landscapes

Source substitution (refer Section 4.2).

4.2 Alternative Water Sources

There are a range of non-potable water sources that could be considered as part of an integrated water strategy for Yaroomba Beach.

Alternative Water Sources include:

Rainwater harvesting

Stormwater harvesting

Ground water extraction

Recycled water from a centralised facility

Localised sewer mining.

The key non potable water uses include:

Toilet Flushing (via Dual Reticulation) – not feasible or endorsed by Unitywater

Irrigation of gardens and landscaped areas – recommended

Topping up the Lake (not included in EP calculations) – recommended.

Table 6 – Preliminary Assessment of Alternative Water Sources

Option Advantages Constraints Recommendation

Rainwater Harvesting (roof)

Reduces runoff and erosion

Potential improvement in local waterway health

Widely accepted by community

Minimal design requirements

Controlled catchment and first flush devices achieve a relatively high water quality

Increased electricity consumption to operate rainwater pumps

Limited yield per dwelling due to spatial constraints i.e. limited roof space and large water tanks etc.

Should be considered


Option Advantages Constraints Recommendation

Stormwater harvesting

Utilises future impervious surfaces

Large storage capacity reduces localised flooding

Improves water quality

Can be aesthetically pleasing e.g. wetlands, buffer zones etc.

Opportunity to incorporate WSUD principals such as swales and litter traps

Large investment required upfront for design and construction

Larger ongoing maintenance requirements / costs for WSUD treatment devices to be borne by body corporate or Council

Risk of over extraction of stormwater flows impacting on natural environment

Impact on development layout

Should be incorporated

where possible

Groundwater Harvesting

Reduced storage and distribution requirement as can be extracted as needed and where needed

Limited treatment required

Over extraction could impact on lake levels and cause salt water intrusion

Increased energy consumption through use of pumps

Should be incorporated for

Open Space Irrigation

Recycled water

Reliable supply achieves large reduction in potable water usage

Reduction in wastewater discharge volume and loading

Effective short-term water supply for irrigation while Coolum STP operational

Potentially sunk costs if infrastructure becomes redundant once the STP is decommissioned

Large investment required upfront for design and construction of distribution network

Large maintenance/labour costs

Further treatment is likely to be required to bring the water quality up to Class A+ required for public irrigation and topping up of the lake.

Not considered feasible due to loss of supply in

the future.

Sewer mining

Source for non-potable water for irrigation of open spaces after decommissioning of Coolum STP i.e. long-term solution

Potentially large reduction in potable water usage

Reduces wastewater loads on trunk network, reduces sewer overflows

Reduction in wastewater discharge volume and loading

Large investment required upfront for design and construction

Larger ongoing maintenance requirements / costs to be borne by body corporate or Council

Most expensive solution

Should be considered only if a need for a large

and reliable source of non-

potable water is identified

While demand management through source substitution could be implemented at Yaroomba Beach to reduce potable water demand, significant work would be required to develop a sound business case to negotiate an associated reduction in potable water supply infrastructure requirements.

For the purpose of this initial investigation, zero reduction in potable water demand has been adopted as a conservative basis for the water supply infrastructure assessment outlined in Section 5.


5 WATER SUPPLY INFRASTRUCTURE

The following sections outline the water supply infrastructure required to accommodate for the proposed development of Yaroomba Beach.

For the purpose of this initial investigation, zero reduction in potable water demand has been adopted as a conservative basis for the assessment of water supply infrastructure requirements.

5.1 Bulk Water Source Capacity

Water supply for the Coolum area is sourced from Image Flat WTP, which is located approximately 30km to the south west of Coolum. A new off take and cross connection to the Northern Pipeline Interconnector (NPI) is currently being implemented downstream of Image Flat WTP, to supplement supply to the Coolum area from the SEQ Water Grid.

On this basis, source water capacity is considered adequate to support future growth in the area, including the proposed development.

5.2 Bulk Water Network Capacity

Planning undertaken by Unitywater in 2010 identified that the existing bulk water network which extends between Image Flat WTP / NPI and Coolum and onto the Peregian Springs growth area, is currently operating at capacity. Parts of this system have a history of frequent failure.

Based on past planning, any future growth in Coolum or Peregian Springs would trigger a major augmentation of this system known as the North Shore Mains, at an estimated capital cost of $40M - $50M. Unitywater developed a staged implementation plan extending between 2011 and 2021. The practicality of this solution is problematic due to alignment issues and is subject to detailed planning.

The adoption of new design standards in June 2013 as part of the SEQ Design and Construction has resulted in a 40% reduction in adopted water demands. It is likely that this significant change will effectively defer the need for future augmentation of the North Shore Mains until 2026. Renewal or reconfiguration of this system may still be required to address recent failures.

The impact of reduced demands on planned augmentations was being assessed by Unitywater in 2013. Based on discussions with Unitywater in 2013, the assessment and augmentation of the North Shore Mains is considered to be a regional issue outside the scope of a development application for Yaroomba Beach. Further assessment by Unitywater and liaison between regional stakeholders is required to determine the need for augmentation and the preferred approach.

5.3 Storage Requirements

The proposed development site falls within the Coolum Intermediate Level Zone (ILZ), supplied from the 13.3ML Lang Street Reservoir (TWL 70m AHD) which is located directly north of the site. Supply currently passes through the Lang Street Reservoir before being delivered to both the Coolum Low Level and Peregian Springs zones.

The Ground Level storage requirements for Yaroomba Beach are 1.3 ML based on the current DSS. Based on current DSS the capacity of the Lang Street Reservoir is adequate across all planning horizons, as shown in Table 7, and has sufficient spare capacity at 2031 (4.8 ML) to accommodate the proposed development at Yaroomba Beach.


Table 7 – Reservoir Storage Analysis (2017 DSS and Population Forecast, Unitywater) – Excluding current Yaroomba Beach Proposal

Year Population

Demand L/s Demand ML/d

Current Capacity

Required Capacity

Spare Capacity

Storage Capacity

EP AD MDMM MD PH AD MDMM MD ML ML ML ML

2014 14,841 45 64 84 163 3.9 5.6 7.3 13.3 6.0 7.3 Adequate

2016 15,331 46 67 87 169 4.0 5.7 7.5 13.3 6.2 7.1 Adequate

2021 16,584 50 72 94 182 4.3 6.2 8.1 13.3 6.8 6.5 Adequate

2026 18,429 55 80 105 203 4.8 6.9 9.0 13.3 7.5 5.8 Adequate

2031 20,373 61 88 116 224 5.3 7.6 10.0 13.3 8.3 5.0 Adequate

2036 20,924 63 91 119 230 5.4 7.8 10.3 13.3 8.5 4.8 Adequate


Previous planning allows for a 6ML augmentation of the Lang Street reservoir in 2026 to cater for growth in the area outside of the Coolum Intermediate Level zone (therefore not relevant to Yaroomba Beach) as construction of additional storage at both Coolum High Level Reservoir and the Coolum Low Level Reservoirs sites is not feasible.

5.4 Trunk Network

In 2010, Unitywater constructed a dedicated DN375 outlet main from Lang Street Reservoir down Wattle Street, over a length of 670 m. This main increased the capacity of supply to the area and improved general system operation, and was required to accommodate future growth at Yaroomba Beach.

The capacity of the remaining external trunk network is adequate to cater for the proposed development. An existing DN300 trunk water main runs along David Low Way, directly past the proposed development site. Under worst case conditions (Fire flow plus peak demand) the velocity in this main does not exceed the maximum allowable velocity of 2.5 m/s and sufficient pressure can be maintained across the development.

5.5 Connection & Metering

The proposed connection to the Unitywater network is at the proposed main entry to the development on David Low Way. It is a Unitywater requirement to install a master meter at the boundary of community title developments, with sub-meters within the development. Unitywater may give approval for independent water services, with no master meter, if there is no common property usage. For this development, common property usage is expected and therefore a master meter, with sub-meters will be required.

5.6 Reticulation Network

Preliminary internal layouts for water supply infrastructure have been developed based upon the proposed internal road layout. The internal layouts are within private property and are therefore subject to Plumbing Approval through Council, rather than Unitywater approval. The exact configuration and sizing of the network will be developed at a later stage of the project, however it is expected that it will consist of the following:

A potable water supply loop main

A boosted fire main to service street hydrants, and hose reels and sprinklers in the apartment buildings and hotel.


6 SEWERAGE INFRASTRUCTURE

6.1 Sewage Treatment Strategy

Sewage for the Coolum area is currently directed to Coolum Sewage Treatment Plant (STP), located approximately 3km west of the proposed development area. A small recycled water scheme is also in place to distribute treated effluent from the Coolum STP to irrigate the Palmer Coolum Resort & Golf Course and nearby public golf course on an as needed basis. The remainder of treated effluent from this plant is transported south and discharged to the Maroochy River downstream of the confluence with Coolum Creek.

The Coolum STP is generally considered to be in fair to good condition. A demonstration wetland was constructed at the STP, with the trial due to finish in 2019.

In 2013 Unitywater was developing a long term treatment strategy which provided a blueprint for investing in wastewater infrastructure for the Sunshine Coast over the next 50 years (CH2MHill Treatment Services Strategy - Strategy Report, November 2012). This strategy involved the decommissioning of Coolum STP in 2019 and diverting the sewage south to the Kawana STP. Unitywater has since revisited this strategy and it is likely that Coolum STP will be diverted to the Maroochydore STP instead, however the timing of this is not yet known.

The timing of this diversion will be subject to future detailed planning and business case development by Unitywater. However, based on the adopted strategy, projected growth at Yaroomba Beach (3,162 EP) would ultimately need to be catered for at the Maroochydore or Kawana STPs.

The scope and associated cost of infrastructure required to implement the diversion of sewage from Coolum STP to the Maroochydore or Kawana STPs will be significant and subject to extensive further investigation by Unitywater. This strategic diversion is considered outside the scope of a development application for Yaroomba Beach.

6.2 Trunk Network

The overall treatment strategy is likely to have a minimal impact on the local sewerage network. Sewage will continue to be transferred to the Coolum STP site, where it will be re-pumped to the Maroochydore or Kawana STP.

Previous planning for the area was based on the assumption that growth within Yaroomba Beach area would be directed south to the existing pump station CLM087 which injects into a common rising main with CLM085, extending directly west to the Coolum STP. With any additional growth on the western side of David Low Way directed north to CLM091, which injects into a large common rising main system which extends down from CLM081 and receives injected flow from CLM097, CLM091 and CLM096 prior to discharging to Coolum STP.

It is proposed that this plan is maintained, and all loading from Yaroomba Beach directed towards pump station CLM087. This system would have sufficient capacity to cater for flow from over half of the development, up to Precinct 4. For Precinct 4 and 5, pump station CLM087 would need to be augmented to increase the flow by 17 L/s. These calculations are based on Method 2: Unitywater Proposed (Table 2), however if a less conservative load was adopted, as per Method 3: Alternative SEQ Tourism Rates (Table 2), the flow rate would be reduced by 10 L/s to 27 L/s, bringing the projected load at 2031 for CLM087 to 60 L/s, reducing the augmentation of the pump station to only 7 L/s and delaying it until Precinct 5.


Table 8 – Pump Station Assessment

Pump Station

Existing dual pump

capacity (L/s)

Projected Load at 2036

(L/s)

Spare Capacity at

2036 (L/s)

Load from Yaroomba

Beach (L/s)

New Projected

Load at 2036 (L/s)

Capacity

CLM087 53 33 20 37 70 Augmentation

Needed

Increase 17

In an earlier assessment undertaken in 2013, for a different layout, it was estimated that the increase in flow at CLM087 would be 21 L/s. This required a pump station augmentation. While the single rising main downstream of CLM087 would have sufficient capacity across all planning horizons, the length of combined rising main downstream of CLM085 (Points B to C) would have required augmentation (approximately 1,500 m of DN300) when the pump station was upgraded. Appendix B shows a marked-up excerpt of the Coolum Sewerage Scheme Network Master Plan - Existing Sewer Network (South) from 2013 showing the layout of the existing and proposed system upgrade (Green line).

Given the increase in flow is now 17 L/s, it is likely that similar upgrades will be required to the pump station and rising main. Further discussions with Unitywater will be required during the approval phase to determine the need for and the timing of any upgrades required.

6.3 Reticulation Network

The early stages of the original Beachside Precinct are currently serviced by a private sewerage network, including a pump station which was designed to cater for the historical 2005 development proposal. This pump station has sufficient depth to receive gravity flow from across the Yaroomba Beach site. Negotiation with the asset owners is required to determine the possibility of utilising available capacity in the existing private sewerage network.

While details of the existing private assets have not been provided, it is understood that this pump station and rising main have sufficient capacity to cater for 27 L/s PWWF, which is sufficient for up to and including Precinct 3 (23 L/s PWWF) plus the previous residential precinct. Augmentation or a new pump station and rising main would be required ahead of Precinct 4 on the basis of the proposed staging plan.

Preliminary internal layouts for sewerage reticulation infrastructure have been developed based upon the site contours and finished surface levels, with consideration to the final internal road layout. The internal layouts are within private property and are therefore subject to Plumbing Approval through Council, rather than Unitywater approval. The exact configuration and sizing of the network will be developed at a later stage of the project.

6.4 Recycled Water

A small recycled water scheme is also in place to distribute treated effluent from the Coolum STP to irrigate the Palmer Coolum Resort Golf Course and nearby public golf course on an as needs basis.

The overall sewerage treatment strategy for the Sunshine Coast involves decommissioning the Coolum STP, which will end the supply of recycled water to the Coolum area. All wastewater will be redirected to the Maroochydore or Kawana STP, and Unitywater does not have plans to implement a new recycled water scheme to distribute treated effluent for open space irrigation at this stage. The timing for this has not yet been finalised.

Given that a long term supply of recycled water supply is unavailable, a localised sewer mining facility could be considered to maintain recycled water supply to the Coolum area, however it is unlikely


that this system would be feasible for Yaroomba Beach in isolation and should be considered on a regional scale. The preferred location for a facility would be at the existing Coolum STP site to utilise available treatment, storage and recycled water distribution infrastructure where possible.


7 CONCLUSIONS

The following conclusions can be drawn from this study:

Population and Demand

The estimated population of the proposed development is approximately 2,378 Equivalent Persons for Water (EPW) and 3,162 EP for Sewer (EPS).

The estimated population is made up of three areas:

o Short-term (Hotel & Serviced Apartments): 682 EPW & 777 EPS

o Residential: 1,638 EPW & 2,319 EPS

o Retail / Commercial & Community: 58 EPW & 66 EPS

Unit water demands have reduced significantly (40%) since 2005 across South East Queensland.

The proposed water demand for Yaroomba Beach is 0.62 ML/day (average day).

The projected sewage load for Yaroomba Beach is 0.63 ML/day (average dry weather flow).

The demand for non-potable water for irrigation is estimated to be 0.14 ML/day (peak day).

Demand Management

Given water demands have significantly reduced since 2005, there is limited opportunity to achieve additional water savings through targeted demand management strategies.

The following demand management initiatives are recommended at Yaroomba Beach:

- Native vegetation and drought tolerant landscapes

- A combination of stormwater and ground water harvesting (spear bores) to source water for open space irrigation.

The supply of recycled water to the Coolum area will stop following the planned decommissioning of Coolum STP. A localised sewer mining facility could be implemented to maintain a reliable non-potable supply to irrigate local golf courses and open spaces; however, it is unlikely that this system would be feasible for Yaroomba Beach in isolation and should be considered on a regional scale.

Water Supply Assessment

Water supply for the Coolum area is sourced from Image Flat WTP, supplemented by the SEQ Water Grid via a cross connection to the NPI. Source water capacity is adequate to support projected future growth in the area.

Water supply to the Coolum area is currently constrained by the capacity of the North Shore Trunk Mains. Unitywater are investigating the staged augmentation of this system and advised in 2013 that this bulk supply issues are outside the scope of a development assessment.

The proposed development site falls within the Coolum Intermediate Level Zone (ILZ). There is adequate storage capacity to accommodate growth across all planning horizons and the external trunk network has sufficient capacity to cater for growth.


The internal water reticulation network will be within private property and therefore subject to Plumbing Approval through Council, rather than Unitywater approval. It will consist of both a potable water supply loop main and a separate fire main. The exact configuration and sizing of the network will be developed at a later stage of the project.

Sewerage Assessment

Sewage for the Coolum area is currently directed to Coolum Sewage Treatment Plant (STP). Based on a long term servicing strategy, this STP shall be decommissioned and flow diverted south to the Maroochydore or Kawana STPs. The timing of this diversion is not yet confirmed and will be subject to future detailed planning. Sewage from Coolum will continue to be transferred to the Coolum STP site, where it will be re-pumped to the Maroochydore or Kawana STP.

The preferred strategy for Yaroomba Beach is to direct flow to the existing pump station CLM087 which injects into a common rising main with CLM085, extending directly west to the Coolum STP. It is expected that this has capacity for up to the first three precincts, however further discussions with Unitywater will be required during the approval phase to determine the need for and the timing of any upgrades required.

There is a private sewerage network which provides an existing connection to the Yaroomba Beach site and should have sufficient capacity to cater for the first three precincts, plus the existing residential precinct. Coordination with the Body Corporate / asset owner is required to facilitate the connection. Augmentation or a new internal pump station and rising main would be required prior to Precinct 4.

Preliminary internal layouts for sewerage reticulation infrastructure have been developed based upon the site contours and finished surface levels, with consideration to the final internal road layout. The internal layouts are within private property and are therefore subject to Plumbing Approval through Council, rather than Unitywater approval. The exact configuration and sizing of the network will be developed at a later stage of the project.


APPENDIX A MASTERPLAN LAYOUT

5-7 STOREY RESORT COMPLEX2, 7 STOREY SERVICED APARTMENTS

4 STOREY APARTMENTS

4 STOREYAPARTMENTS

EXISTING RESIDENTIAL

4 STOREY APARTMENTS

3 STOREY DWELLINGS

4 STOREYAPARTMENTS

VILLAGE CENTRE

FRONTAL DUNE

PARABOLIC DUNE

LAKE

LAKE

PARK

BEACH

DAVID LOW WAY

4 STOREY APARTMENTS

1 STOREYTRANSFERSTATION

ENTRY

PRECINCT 5LAKESIDE NORTH

3 STOREY DWELLINGS

PRECINCT 4LAKESIDE SOUTH

PRECINCT 2YAROOMBA BEACHCENTRAL

PRECINCT 3YAROOMBA BEACH SOUTH

4 STOREYAPARTMENTS

2STO

REY

DWEL

LING

S

3 STOREY DWELLINGS3 STOREY DWELLINGS

PRECINCT 1YAROOMBA BEACH NORTH

3 STOREY DWELLINGS

LOT 14 SP238214

LOT 902 SP269561

1 STOREY RETAIL & SURFLIFE SAVING AMENITIES

LOT 19 SP238214

EXISTING BEACHACCESS PATH

EXISTING BEACHACCESS PATH

COOLUMBEACHSIDECTS 38537

BELLE MARECTS 431571-2 STOREY

RETAIL,EDUCATIONCENTRE,COMMERCIAL

KEYEXISTING TREESTO BE RETAINED

PRECINCT BOUNDARY

DEVELOPMENT ZONE

0 20 40 80m

1:1000

Scale Project Name Drawing

HASSELLOriginal Sheet Size A1- 841 x 594mm

Revision Date

1 : 1000 @ A1 A_0002YAROOMBA BEACHMASTERPLAN MASTERPLAN - PROPOSED

A DEVELOPMENT APPROVALAPPLICATION

10-03-17


APPENDIX B PREVIOUSLY PROPOSED AUGMENTATIONS (2013)


DOCUMENT / REPORT CONTROL FORM

Project Name: Yaroomba Beach Water Supply & Sewerage Infrastructure Assessment

Project Number: 30031110

Revision Number: 6

Revision History

Revision # Date Prepared by Reviewed by Approved for Issue by

1 30-07-2013 Alice Twomey Sarah Board Chris Green

2 9-08-2013 Sarah Board Chris Green Chris Green



5 24-04-2017 Karina Thiele Carl Wilkinson Carl Wilkinson

6 03-05-2017 Karina Thiele Carl Wilkinson Carl Wilkinson

Issue Register

Distribution List Date Issued Number of Copies

Unity Water 1

SH Coolum Pty Ltd 1

Office Library [South Brisbane] 1

SMEC Project File 1

SMEC Company Details

Carl Wilkinson

Level 1, Building C, 6 Innovation Pkwy, Birtinya QLD 4575

Tel: +61 7 3029 6700 Fax: +61 7 5437 6525

Email: [email protected] Website: www.smec.com

The information within this document is and shall remain the property of:

SH Coolum Pty Ltd

http://www.smec.com/

water supply & sewerage infrastructure for yaroomba beach

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