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Rylstone WS R iver Pumping Station

Concept Design Report

Prepared for Mid-Western Regional Council

Report No. WSR 09022A (Final Draft)September 2009


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Forward

This document has been prepared by the NSW Public Works for Mid-Western Regional

Council. Public Works acknowledges the assistance provided by the staff of Mid-WesternRegional Council. Especially, the assistance of Brett Corven, Carrie Hooper, Steve Hanthorn,Scott Jackson and Peter Dunn in providing information pertinent to the preparation of thisreport is greatly appreciated.

NSW Water Solutions Project Team members involved in this investigation were:

Dayan Gunasekera

Ken Kay

Vu Dao

Abdur Razzak

George Fuller

Sisitha Pathirana

Nicholas Kaparos

Document History

Version Date Issued

Draft 11th September 2009

Final Draft 20th September 2009

Final To be issued

Contact: Kamal FernandoT 02 9372 7869F 02 9372 7877E [email protected]


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Pumping Station Building

The pumpwell would be enclosed in a building (13m x 7m) which would consist of two rooms,i.e. Switch Room and PAC Room. The Switch Room would be directly above the pumpwelland would accommodate the electrical and telemetry switch gear assembly. The Switch Roomalso provides the access to the pumpwell and supports the monorail. The existing PAC plant

at the WTP site would be relocated in the PAC room. The Switch Room would have two doors(1.2m and 2-3m wide) while the PAC room would have a GI mesh front with a door made ofsimilar material. The building would be a brick building on reinforced concrete floor supportedon concrete piers founded on the bedrock.

System Hydraulics and Operation

In order to minimise the depth of the pumpwell, the suction main and the trunnion arm(except the trunnion & the pipe through the damwall) would be DN 300. The delivery mainwould be DN250.

For efficient and flexible operation, the pump would be provided with variable speed drives. Apressure sustaining valve would also be provided at the end of the rising main near the

treatment plant.

Trunnion

The trunnion, if made of stainless steel, would last more than 70 years. If made in mild steel(epoxy coated after fabrication) it would last about 50 years. Without designing and preparingshop drawings, the price of the trunnion cannot be estimated/obtained. The supply cost ofstainless steel is generally 3-4 times higher than mild steel, however, with the labour involvedin fabrication and the epoxy coating, the overall price difference between the two is notexpected to be significant.

It is recommended to include a mild steel trunnion in the tender as a conforming bid with analterative tender price invited for a stainless steel trunnion.

The trunnion arm would be made of epoxy coated mild steel.

Pipelines

Due to the rocky condition and the high overburden (3-4m backfill), rubber ring jointedcement lined ductile iron (DICL) pipes are recommended on a well-graded bedding. For thesuction main, rock excavation is anticipated for about 70% of its excavation volume.However, a lesser quantity of rock excavation is expected for the delivery main (~25%). Bothpipelines will be buried except the first 10m length of the suction main which will besupported on concrete piers founded on the bedrock.

The pipelines would be connected to the existing lines with Tees enabling the use of the

existing system during construction and afterward.

Electrical and Telemetry

The existing transformer (100 kVA) would be sufficient for the new pumps and the PAC plant.It is proposed to provide a new 100kVA transformer on a new pole near the new pumpingstation. The existing transformer and the associated overhead powerlines would be removedonce the existing system is de-commissioned. Underground power and communication cablesshould be laid from the new pump station to the dam.

The pumps would be automatically controlled depending on the requirements of the WTP. Inaddition to pump controls, necessary monitoring, alarms and warnings signals would beprovided to the treatment plant control centre via telemetry. A lightening protection system

would also be provided.


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Environmental aspects

The proposed pipeline alignment is not expected to disturb much vegetation, especiallymature trees. As such, for the purpose of the concept design there are no real constraints toconsider. It is recommended, however, that vegetation removal be kept to a minimum and nomature eucalypts be removed during the construction. The pipeline alignments have beenselected avoiding these trees.

There are no evident Aboriginal cultural heritage constraints to the project.

Cost Estimation

The estimated capital cost for the pumping station and associated works is $0.94M. Theanticipated annual O&M cost (excluding replacement cost) is $31,000/year.

Testing and commissioningThe existing raw water supply needs to be interrupted at various times for connections of thenew system to the existing infrastructure. It will be necessary to maintain the supply duringthe period of construction and installation of the new system. It is therefore considered thatthe connection and installation should be carried out in a manner which will allow for achange over before the old system is de-commissioned.

____ . ____


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Rylstone Water Supply NSW Water SolutionsRiver Pumping Station Concept Design NSW Public Works

d:\rylstone\intake\final draft report\rylstone rps - concept report ( finaldraft).doc i

Table of Contents

Forward i

Executive Summ ary ii

Table of Content s i

1 Introduction 3 1.1 Project Background 31.2 Existing Raw Water Pumping Station 31.3 Proposed Pumping Station 31.4 Concept Design 41.5 Report Structure 4

2

Proposed pumping Station 5

2.1 Infrastructure components 52.2 Pumpwell 5

2.2.1 Location 52.2.2 Dimensions 52.2.3 Type of well 82.2.4 Constructability 82.2.5 Pumping Machinery 8

2.3 Pumping Station Building 112.4 Pits for valves and PAC injection 122.5 Electrical works 12

2.5.1 Electrical works 12

2.5.2

Telemetry 122.5.3 Power supply to site 13

3 Hydraulic Analysis 14 3.1 Size of trunnion and pipelines 143.2 Operational aspects 143.3 Pump duties and system characteristics 15

4 Pipelines 17 4.1 Suction Pipeline 174.2 Delivery Pipeline 184.3 Trunnion 18

5 Miscellaneous 20 5.1 Environmental assessment 20

5.1.1 Ecological Issues 205.1.2 Aboriginal Cultural Assessment 205.1.3 Consultation 20

5.2 Temporary water supply 205.2.1 Testing and commissioning of pumps 215.2.2 Access to the Pumping Station 21

6 Cost estimates 22 6.1 Capital Cost 226.2 Operation and Maintenance Costs 22


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d:\rylstone\intake\final draft report\rylstone rps - concept report ( finaldraft).doc ii

7 Conclusion & Recommendation 24

8 Reference 25

Appendices

Appendix 1: Preliminary Geotechnical Assessment

Appendix 2: Capital and O&M Cost Estimates

Figures

Figure 1: Proposed Pumping Station and Pipelines Concept Layout 6

Figure 2: Ground Profile across Pumpwell 7

Figure 3: Proposed Pump Installation Arrangement 9

Figure 4: Pumpwell Plan & Sectional Elevation (4m well) 10

Figure 5: Pumping Station Building Layout Plan 11

Figure 6: Hydraulic Grade Lines for 67 L/s & reduced flows. 15

Figure 7: System characteristics and a typical pump curve 16

Figure 8: Connection of new suction pipeline to existing pipe 17

Figure 9: Long Section of Suction Pipeline 17

Figure 10: Long Section of Delivery Pipeline 18

Tables

Table 1: Cost estimates for the pumping station and associated works 22

Table 2: Annual Operation & Maintenance Cost for the pumping station 23


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d:\rylstone\intake\final draft report\rylstone rps - concept report ( finaldraft).doc 3

1 Introduction

1.1 Project BackgroundThe Rylstone water supply system currently provides potable water to Rylstone, Kandos,Charbon and Clandulla villages.

Mid-Western Regional Council (MWRC) engaged the NSW Public Works to carry out aninvestigation of the Rylstone water supply system. The investigation included a detailedreview of major infrastructure components of the system and an assessment of upgradesnecessary for the future demands.

Provision of a new raw water pumping station for the Rylstone water supply system is one ofthe priority augmentation works recommended in this strategy study.

1.2 Existing Raw Water Pumping StationThe existing raw water pump station draws water from the Rylstone Dam which is located onthe Cudgegong River. The pump station is located approximately 35m downstream of thedam by the side of the Cudgegong River. The suction pipeline which runs through the damwall to the pump station consists of a trunnion enabling drawing off water just below thewater surface. The dam and the pump station were constructed in the early 1950s and havebeen in operation since then.

Prevailing issues with the existing intake include: (a) an inability to draw water below RL577m level (30% unusable storage), (b) high head losses through the suction main; (c)

splash flooding of the pumping station during spilling of the dam; (d) aging of the pumps andthe pumping station; (d) poor condition of the trunnion; and (e) insufficient pumping capacityto meet the future demand.

1.3 Proposed Pumping StationThe recommended augmentation works for the Rylstone intake are as follows.

- A dry pump well accommodating pumping units (one duty/one standby);

- A building to accommodate: (a) electrical switchgear and other instrumentsassociated with pump operation and (b) the PAC plant which is currently at thetreatment plant;

- A new suction pipeline from the dam to the pumpwell;

- A new delivery pipeline from the pumpwell to the existing rising main;

- A new trunnion (replacement);

- Pits for valves and PAC injection;

- Electrical and telemetry works; and

- Associated minor works for the proper completion and operation of the system.


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1.4 Concept DesignMWRC engaged the NSW Public Works to undertake a concept and detailed designs including

tender documentation for the proposed pumping station. Specific tasks required to be carriedout at the concept stage included the following.

1. Engineering survey, geotechnical investigation and environmental assessment;

2. Concept design of the pump well (location, diameter, bottom floor level, top level)including constructability (rock excavation, stability, type of pump well material etc.);

3. Finalisation of the hydraulic analysis to determine the pump duties, sizes of trunnion armand suction/delivery pipelines, pipework configuration within the well and operationalcontrol requirements;

4. Concept design of the suction and delivery pipelines including alignment, depth, rock

excavation, constructability etc.;

5. Design methodology of the trunnion including type of material;

6. Adequacy of the power supply requirements; and

7. Identification of any environmental issues related to the above works.

1.5 Report StructureThe report structure is as follows.

Chapter Contents

1 Project background and concept design tasks

2 Concept design of the pumpwell and the building including location selection,type, size and constructability of the well and geotechnical aspects

3 Hydraulic analysis including sizing of the trunnion, suction/delivery pipelinesand pumps including operational aspects

4 Pipelines and trunnion including material types, alignments, geotechnicalaspects, connection to the existing pipes and constructability

5 Miscellaneous information such as environmental issues, temporary watersupply during construction, testing and commissioning

6 Capital and O&M cost estimates

7 Conclusion followed by References and Appendices


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2 Proposed pumping Station

2.1 Infrastructure componentsThe main civil infrastructure associated with the pumping station are:

-A dry well to accommodate pumps (pumpwell);

-A building to accommodate electrical switch gear assembly, other control units and a PACplant;

-Pits for valves and PAC injection;

The trunnion and suction/delivery pipelines are discussed in Chapter 4.

2.2 Pumpwell2.2.1 Location

An approximate location of the pumpwell was identified during a joint site inspection carriedout at the inception meeting. The final location of the well was determined taking intoconsideration the topography, slope of the bank, depth to bedrock, environmental aspects,suction main invert level, flood levels and other constraints such as an overhead power line.

It was not possible to locate the well 10m away from the powerline due the steepness of theslope. Therefore it was decided to re-locate the powerline to suit the well and the building. Anew transformer would be installed on a new pole closer to the new pumping station. Theexisting transformer including the power line would be removed after commissioning of the

new pumping station. The proposed location of the well and the new power pole are shown inFigure 1.

2.2.2 DimensionsGeotechnical investigation results show that the bedrock is of very high strength andtherefore rock excavation would be very costly. The size of the pumpwell has therefore beensized as small as possible to minimise the cost of construction.

In order to reduce the size and provide clear space as much as possible within the well, theinlet (suction) bifurcation has been made outside of the well. It is envisaged that thisarrangement would be suitable because of the method of rock excavation/removal. The

discharge isolation valves and non return valves have been arranged in a separate valve pitoutside the pump well to once again to provide clear space in the well.

The minimum size of the well which could accommodate the above pumps would be 3.6m,however a 4m diameter well is recommended considering other issues such as access,working space etc. This is further discussed in section 2.2.3 to 2.2.5.

The bottom level of the well should suit the invert level of the incoming suction pipeline andthe depth required for the pump installation. Allowing a gradient equivalent to the headlossand another 0.5m for the pump installation, the floor level of the well was selected as RL570.0 m.

The top level of the well was selected as RL 575.5m which is 2.2m above the 100 year flood

level. A cross section of the pumpwell showing the profile of the bedrock is given in Figure 2.


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Suction Main

Connection to

the existing pipe

35m

New power pole

& transformer

Pumpwell

NRV Pit

0 5m 10m

Figure 1

Dam Wall

Existing Pumping StationExisting Suction Pipeline

Pumping

station building

Proposed Works are

shown in red

Indicative alignment for the

access road is shown in green


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2.2.3 Type of wellThe well could be constructed either in-situ or with pre-cast concrete cylinders. Pre-castmethod is generally cheaper in excavatable materials, if sunk as a caisson, than cast-in-situ

construction especially for smaller diameters. Because of the anticipated rock, an open cutexcavation would be required which lends itself to cast-in-situ construction. The otheradvantage of a cast-in-situ well is that it would be a monolithic construction unlike the pre-cast concrete wells which have joints between each cylinder (i.e. at 1.22m spacing). On theother hand, the available largest pre-cast concrete cylinder size is 3.6m.

It is recommended to design a 4m diameter cast-in-situ well, however, an alternative tenderprice for a pre-cast concrete well of 3.6m diameter should also be invited. If the alternativetender price (3.6m pre-cast well) is significantly less than the conforming tender (4m cast in-situ well), it would be worth re-considering a 3.6m well.

2.2.4 ConstructabilityThe major constraint in the construction of the well would be the excavation of rock whichwould be encountered at a depth of around 0.5m. The rock has a yield strength of 110 -130MPa requiring blasting. Because the site is on close proximity to the dam blasting would notbe allowed except pre-splitting which is a slow process. Excavation works, if carried out bypre-splitting the rock, would take 3-4 weeks as it has to be done stage by stage.

It may be possible to excavate vertically without shoring, however, it should be carried outafter a thorough examination of rock characteristics and on advice from geotechnical experts.

Vertical excavation would enable construction of the well either in-situ or with pre-cast units.

The access to the well during construction may be from the trench excavated for the suctionmain. Accordingly, the excavation near the suction main entry point to the well would be

larger than the normal pipeline trench enabling installation of the bifurcation pipework outsidethe well.

2.2.5 Pumping MachineryVertically mounted axially split centrifugal pumps (one duty/one standby) each with a duty of67 L/s at 23 m are recommended for the Rylstone river pumping station. These pumps havean efficiency around 80-83%.

The pump installation arrangement is shown in Figure 3. As shown in the figure, the pumpswould be installed with thrust bearing dismantling joints on the discharge side, to assist pumpremoval.

By using standard joints for pumping machinery to deliver 67 L/s larger pumps can beinstalled for 85 L/s by substituting these with short bodied thrust bearing dismantling joints, ifrequired, in the future.

The plinth height to 67 L/s pumps and pipework centre height will also allow for theinstallation of larger pumps for flow rates up to 85 L/s.

As discussed before, the non return valves would be installed outside the pumpwell tomaximise the space within the well. The two delivery pipes from the pumps would come upthrough the wall and then under the building. Each pipeline will have a non return valve andan isolation valve on either side prior joining together. The PAC injection point would be onthe common main.


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The pump motors are air cooled and do not require mechanical ventilation. However, forOH&S reasons, an air ventilation system (a duct consisting of a blower or fan) would be

provided.

Figure 3: Proposed Pump Installation Arrangement

A sump will be provided within the well with a submersible dewatering pump. A level censor

will also be provided in the sump to give warning if flooding occurs inside the well. In case ofemergency, the isolation valve on the suction main near the dam could be closed if theisolation valves in the pump well cannot be reached.

The operational aspects of the pumps are discussed in Section 3.2. A typical cross section ofthe pumpwell is shown in Figure 4.


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Figure 4: Pumpw ell Plan & Sectional Elevation (4m well)


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2.3 Pumping Station BuildingThe pumping station building would be above the pumpwell enclosing the well within the

building. The building would consist of two rooms. The room directly above the pumpwell(Switch Room) would accommodate the electrical switchgear for the pumps, telemetrycontrol, monorail etc.. The other room (PAC Room) would accommodate the PAC plantwhich is currently at the treatment plant. The layout plan of the building is shown in Figure 5.

Figure 5: Pumping Station Building Layout Plan

The building would be a brick building with a steel portal framed structure on a reinforcedconcrete foundation. The walls would be single brick. The foundation would be a concreteslab and beam arrangement supported on concrete piers founded on bedrock. The pier heightwould vary from 0.5m to 2m and would be anchored to the bedrock using dowel bars. Thefoundation (slab, beams and piers) would be a monolithic structure including the pumpwell.The building would have a single pitched roof made of metal sheet cladding.

The switch room would have two exits i.e. a 1.2m wide door on the southern side (facing theexisting access to the dam) and a 2-3m wide door on the eastern side (facing the dam).

Vehicular access would be provided to both these sides as shown in Figure 1. The PACbuilding would consist of brick walls except the front (southern side) which would be a 25mmgalvanised steelmesh and a door of similar material.

A monorail would be provided for the pumps. The monorail would be extended outside thebuilding through the 3m wide door for about 2m length. The monorail would be hung to across girder which is fixed to the portal frame.

Other necessary features in the building would include handrails around the pumpwell, accessladder to the well with removable ladder entry rail, a davit, ventilation system, switchgearassembly and PLC.

70005500

7000

PAC ROOM

SWITCH

ROOM

SCA

PUMPWELL

Retaining wall

for access road

Davit

Mono Rail

Door

Door

25mm GI mesh & sliding door

Access towell

Service

lines

1200

1200

12001200


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2.4 Pits for valves and PAC injectionNon return valves and isolation valves would be on individual delivery mains from each pump

whereas the PAC injection would be on the common line.

Reinforced concrete pits will be provided for the non return valves (NRV) and PAC injectionpit. The pits will be covered with aluminium gratings. The pit for the NRVs would be commonto both pipelines.

Installation of a new magflow meter near the pumping station is not considered as there is anexisting magflow meter on the rising main near the treatment plant. It is envisaged that lowPAC dosages would not affect the magflow metering performance.

2.5 Electrical works2.5.1 Electrical work s

Main components of the electrical works would include:

- New consumers main from the proposed pole-mounted transformer to the newswitchboard in the pump station building.

- Metering Enclosure (Meter Box);

- Main Switchboard indoor type, Form 3b. This Switchboard will contain a mainswitch, motor starters, feeder for PAC Switchboard, Telemetry compartment, feederfor supplying power to existing Dam equipment, and other essential components;

- Cables and cable supports;

- A lightening protection system; and

- Building services lighting and general purpose power outlets.

A performance based technical specification (clauses) will be prepared for design, supply,installation, testing, demonstration and commissioning of all electrical components. Severalstandard (typical) drawings will be included as part of the specification, however, detaileddesign drawings and related documents would be prepared by the Contractor.

It is assumed that the Council will relocate the existing PAC system including the electrical

switchboard from its present location to the new pump station site. Necessary clauses forprovision of power supply to the PAC electrical switchboard/control panel from the mainswitchboard will be included in the technical specification.

2.5.2 TelemetryIt is understood that the existing ROMTECK telemetry system will be replaced with SERCKControl Telemetry system.

Main telemetry components would include:

- Telemetry RTU;

- Antenna;

- Modification of existing SCADA, if required.


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The Serck Telemetry RTU will be used for automatic control and remote monitoring of pumpstation.

A list of input and output signals will included in the technical specification for automaticcontrol and remote monitoring via existing telemetry system.

A performance based technical specification (clauses) will be prepared for a Design andConstruct (D&C) type contract for design, supply, installation, testing, demonstration andcommissioning of the telemetry system at the pump station.

2.5.3 Pow er supply to siteIntegral Energy advise that the existing pole-mounted transformer is 100kVA rated. Thiscapacity would be sufficient for the power supply to the new pumping station, to the PACsystem (relocated) and to the existing equipment at the Dam.

It is understood that MWRC would liaise with Integral Energy and provide a new transformeron a new pole located closer to the new pumping station (refer to Figure 1 for the proposedlocation for the transformer).


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3 Hydraulic Analysis

Hydraulic analyses were carried out to determine the size of the trunnion, trunnion arm,suction and delivery pipelines, pump duties and the operational control of the pump.

3.1 Size of trunnion and pipelinesThe required flow rate in the year 2031 would be 67 L/s. However, considering the demandbeyond 2031, it was agreed with MWRC that the pipeline and the trunnion be designed for afurther 25% increase in flow i.e. 85 L/s.

The head loss for a flow 85 L/s through a DN250 pipeline would be about 15m/km (includinglosses through specials). This would be equivalent to a loss of 1.5m through the suction

pipeline, requiring the pump well floor to be at RL 569m. If a DN300 pipeline is selected, thepumpwell could be raised by about 1 metre (headloss is 5m/km). Velocity through the DN300pipe for 67 L/s is 0.9 m/s and would not cause any siltation.

Additional cost of increasing the diameter would be approximately $8,500 whereas theincrease in the cost of the pumpwell due to additional rock excavation and the height wouldbe over $20,000. Therefore DN300 is recommended for the suction pipeline.

Additional 1m headloss is not critical for the rising main and therefore DN250 pipeline isrecommended for the delivery line (note that the existing rising main is also DN250).

The size of the trunnion cannot be increased due to installation problems, however, thetrunnion arm may be increased to DN300 which would reduce the headloss further.

Final design data:

Trunnion arm - DN300

Trunnion - DN250

Suction pipeline - DN300

Delivery pipeline - DN250

3.2 Operational aspectsWith the pumping station sited at the recommended location the characteristics for thepumping machinery have been determined with a detailed hydraulic analysis. This will berevised, if necessary, during the design phase to take into account any changes which mayfound necessary.

The dam level varies between RL 572m to RL 580m. In order to deliver a constant flow rate of67 L/s it is proposed that the pumping machinery is controlled by variable speed drives. Thisis the most efficient means of delivering the flow required.

This form of control will also allow for a reduced flow delivery and therefore longer plant runtimes in non-peak periods, which is desirable for stable operation.

The rising main delivers water to the WTP at a level of RL 576.6m. However the rising main

route is over a hill of RL 588m and a further rise at RL 585m.


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HGL - Reservoir @ MOL

586.49

576.6

571

583

585

571.6

580.7

588.3

581.6

576.6

588.7

572.31572.6

589.18589.48

590.01590.42590.9

590.72

587.79588.59

590.04

591.14592.45

591.98

572.6

571.82

570

575

580

585

590

595

0 100 200 300 400 500 600 700 800 900 1000

Distance (m)

Hight/Head(m)

Ground Profile HGL @ 39 l/s HGL @ 65 l/s

Because of the pipe size and flowrate the water will flow under gravity from the RL 588mlevel. The gravity flow under these conditions may cause some sections to not run full and todrain when the pump stops. This can cause some turbulence because of air and water mixing,producing a form of hydraulic obstruction and random intermittent variations in flow.

Maintaining a full pipeline is the best hydraulic operation.

In order to overcome these possible problems it is considered that an artificial head should beinduced at the end of the pipeline with a pressure sustaining valve (PSV). This will maintain afull pipe and provide the optimum hydraulic conditions. It is proposed to install the PSV u/s ofthe existing magflow near the WTP. This is mainly considering any possible modification tothe inlet pipework which may be required as part of the proposed improvements to the WTP.

The pressure sustaining valve could be fitted with two control pilots which would be set to suitthe flow rates with either manual or automatic selection. The hydraulic gradelines are shownin Figure 6.

Figure 6: Hydraulic Grade Lines for 67 L/ s & reduced flows.

3.3 Pump duties and system characteristicsThe type of pumps suitable for this type of drywell arrangement are axially split centrifugalpumps. These pumps could be expected to have an efficiency in the order of 80% plus. Tomaximise the space within the well, the pump motor could be installed in a verticalconfiguration. The duty and operating range of the pump is 67 L/s @ 23m and 39 L/s @11m.For low flow rates the pump would run at a lower speed but almost at the same efficiency.

The system characteristics and a typical pump curve are given in Figure 7.


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Figure 7: System characteristics and a typical pump curve

Rylstone Proposed Raw Water Intake

0

5

10

15

20

25

30

35

40

45

50

55

60

0 10 20 30 40 50 60 70 80 90 100

Flow (L/s)

Head(m)

-35

-15

5

25

45

65

85

Efficiency(%)

Sys Curve (FSL) Sys Curve (MOL) Eta Omega 125-290 B (288) % Curve


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Suction Pipeline - Long Section

565

570

575

580

0 20 40 60 80 100 120Chainage (m)

RL(m)

Ground Level

Likley bedrock

Pipe Invert Level

4 Pipelines

4.1 Suction PipelineThe new suction pipeline from the dam to the pumpwell is 104m long. Considering the rockycondition of the site and the 3-4m backfill over the pipe, ductile iron pipes (rubber ring jointcement lined) are recommended on a well graded bedding. The new suction will be connectedto the existing pipeline at the dam wall with an angle branch and isolation valve as shown inFigure 8.

Figure 8: Connection of new suction pipeline to existing pipe

The alignment of the suction line has been selected to minimise the impact on vegetation.The alignment is mostly through hardrock as shown in Figure 9. The amount of rockexcavation is expected to be around 70% of its total excavation volume of (189m3).

Figure 9: Long Section of Suction Pipeline

Existing pipeline

New

pipeline

New supports

Existing supports

Angle Branch Tee to be installedwith FlxSP & couplings after

cutting the existing pipe

Dam Wall

Note: All fittings to beflanged DICL except

couplings

Existing pipeline

Couplings

So x Sp pipes


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Delivery Main - Long Section

570

575

580

585

590

0 20 40 60 80

Chainage (m)

RL(m)

Ground Level

Likley bedrock

Pipe Invert Level

The excavation volume includes a trench width of 0.9m for construction access. The pipelinewould be laid underground except the first 10m which will be supported on concrete piersanchored to bedrock.

4.2 Delivery PipelineThe new delivery pipeline from the pumpwell to the existing rising main would be 72m long.Considering the rocky condition of the site and being a pumping main, rubber ring jointedcement lined ductile iron (DICL) pipes are recommended. The pipeline would consist of a PACinjection point in a concrete pit. The alignment has been selected avoiding all existing treesand also minimising the rock excavation. Two additional bores were drilled in order todetermine the route which would encounter minimum amount of rock (refer to Appendix A geotechnical results for test bore locations). The final alignment is shown in Figure 1 and thelong section is shown in Figure 10. The amount of rock anticipated for the delivery pipelinewould be about 25%.

Figure 10: Long Section of Delivery Pipeline

The new delivery main would be connected to the existing rising main using an angle branchtee similar to the suction main connection. The provision of the Tee would enable using theexisting rising main during the contract period as well as afterward.

4.3 TrunnionThe trunnion would be designed as a welded fabrication unit of steel plates with necessarybearings etc. It could be made either from stainless steel or epoxy coated mild steel. Thesupply cost of stainless steel is generally 3-4 times higher than mild steel, however, with thelabour involved in fabrication and the epoxy coating, the overall price difference between the

two is not expected to be significant.


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From a durability point of view, the epoxy coated mild steel, if manufactured strictly inaccordance with specified requirements, should last at least 50 years. The stainless trunnionshould last over 70 years.

The trunnion is not a common item fabricated for water supply use and therefore budgetprices cannot be obtained without carrying out the design and preparing shop drawings forthe trunnion.

It is recommended that the trunnion to be made of epoxy coated mild steel, however, analternative tender price should be invited for a stainless steel unit.

The trunnion arm would be made of epoxy coated mild steel.


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5 Miscellaneous

5.1 Environmental assessment5.1.1 Ecological Issues

The proposed pipeline alignment is not expected to disturb much vegetation, especiallymature trees. It is quite likely that some of the vegetation within the study area andsurrounding vegetation conforms to Box-Gum Woodland ecological community, which is listedas a critically endangered ecological community under the Environment Protection andBiodiversity Conservation Act (Commonwealth) and an endangered ecological communityunder the Threatened Species Conservation Act (NSW). While this will require an assessment,

the impact of the works is expected to be very low and will be unlikely to have a significantimpact.

As such, for the purpose of the concept design there are no real constraints to consider. It isrecommended, however, that vegetation removal be kept to a minimum and no matureeucalypts be removed. There were three main Eucalypts identified in the subject area - oneapproximately 10m west of the pump shed and the other two upslope towards the accesstrack in the south of the study area. It is not considered that these 3 trees fall within theproposed pipeline alignment; however, they may suffer some root damage as a result of theworks.

It has been suggested that the alignment be moved closer to the powerline easement so as toreduce the loss of plants and habitat. However, this is not considered to be a viable option, as

it would require excavation deeper into the bedrock in this area and would greatly increasethe cost of the project.

5.1.2 Aboriginal Cultural AssessmentA site inspection carried out by a representative of the Mudgee Local Aboriginal Land Council(LALC) did not identify any Aboriginal items or artefacts which would be impacted by theproposed works. As such, there are no evident Aboriginal cultural heritage constraints to theproject.

5.1.3 ConsultationThe Department of Environment, Climate Change and Water (DECCW) and the Department ofIndustry and Investment (I & I NSW) have been consulted regarding the proposed works. TheNSW Office of Water (within DECCW) has identified an existing licence which authorizes thedam and two 150mm centrifugal pumps (within an extraction rate of 120L/s). As the newextraction rate will not exceed this limit and the extraction location will not be changed, areplacement licence is not required. No other issues have been raised in response to thisconsultation.

5.2 Temporary water supply Arrangement for a temporary water supply at various stages of the construction may be

required. The raw water supply needs to be interrupted during the following activities.


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- Installation of the trunnion;

- Connection of the new suction pipeline to the existing pipeline near the dam;

-

Connection of the new delivery pipeline to the existing rising main;

- Installation of a pressure sustaining valve on the rising main near the WTP;

- During on site testing of pumps (due to limited capacity of transformer)

Investigation on temporary water supply arrangements is outside the scope of work of thisengagement. However, the responsibilities of the temporary supply (i.e. Contractors orPrincipals) and consequences or losses due to delays in completion of these activities etc.should be clearly defined and agreed at the concept stage. This information is required in thepreparation of the tender document.

5.2.1 Testing and commissioning of pumpsThe new pumps would be tested at the manufacturers works prior to installation. The newsystem would be tested when completed. The testing of the new pumps cannot be done whilerunning the existing pumps (a) due to limitation of the power supply; (b) without connectingthe new pipelines to the existing pipelines; and (c) without installing the PSV.

The limitation of power supply would not be a problem if a new transformer is installedwithout removing the existing transformer.

It will be necessary to maintain the supply during the period of construction and installation ofthe new system. It is therefore considered that the connection and installation should becarried out in a manner which will allow for a change over before the old system is de-commissioned. Careful consideration and thoughtful planning is required for a smooth

transition from the existing system to the new system.

5.2.2 Access to the Pumping StationIt is understood that MWRC would construct the access road to the pump station using hiredlabour. Therefore the access road is not included in the construction contract. However, theContractor would have to construct a temporary access road for the construction work andthis access could be upgraded later as the formal access to the new pumping station. Anindicative alignment of the access to the pump station is shown in Figure 1.


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6 Cost estimates6.1 Capital Cost

The estimated capital cost of the works is given in Table 1. A detailed breakdown of costs isgiven in Appendix B.

Table 1: Cost estimates for the pumping station and associated work s

Item Description Amount

1 Trunnion (supply & install) $80,000

2 Suction pipeline (DN300-DICL) 104m long $158,000

3 Pump well (4m dia. X 5.5m deep) $151,000

4 Pumping Station building (13m x 7m) $113,000

5 Delivery pipeline (DN250-DICL) 72m long $80,000

6 Pumps & internal pipework $127,000

7 External pipework including NRV & isolation valves $27,000

9 Electrical and telemetry $120,000

Sub Total $856,000

Contingencies (10%) $86,000

Grand Total (including GST) $942,000

The estimated capital cost has increased by about 20% from the estimated cost in thestrategy study. This is mainly due the rock excavation and the building. The estimate in thestrategy study allowed for a nominal volume of rock excavation which was far exceeded afterthe geotech investigation. The original estimate was for a smaller building outside thepumpwell and did not include PAC Room.

6.2 Operation and Maintenance CostsThe annual operation and maintenance (O&M) cost of the pumping station is based on anannual supply of 500 ML/yr (Commerce, 2009-2). The O&M cost includes the power cost andother maintenance cost of the operation of pumps, other costs involved in the generalmaintenance of system infrastructure but does not include replacement costs. The power costwas assumed to be $0.15/kWh.

Details of O&M costs are given in Table 2.


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Table 2: Annual Operation & Maintenance Cost for the pumping station

Descr iption Uni t Quant ity Rate Amount

Power cost of pumps kWh 49,220 $0.15 $7,383

Maintenance of M&E works-1 Sum $9,160

Maintenance of civil works-2 Sum $6,370

Operational personnel (4hrs/week) hrs 208 $40 $8,320

Total $31,233

Production of raw water -3 ($/kL) $0.06

1). 3% of the capital cost of mechanical and electrical works;

2). 0.5% of the capital cost;

3). Based on an annual supply of 500 ML.


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7 Conclusion & Recommendation

Pumpwell

A 4m diameter cast-in-situ reinforced concrete pumpwell is recommended, however, analternative tender price should be invited for a 3.6m dia. pre-cast pumpwell. The base leveland the top level of the pumpwell are RL 570m and 575.5m respectively. Two verticallymounted axially split centrifugal pumps of duty 67 L/s @ 23m would be provided (oneduty/one standby) with variable speed drives. Non return and isolation valves would beprovided outside the well. The pump well would be equipped/provided with a sump and adewatering pumping system, a level sensor, air ventilation system, access ladder, a davit,handrails, mono rail, a removable grate cover and other necessary items.

Building

The pumpwell would be enclosed in a building which would consist of two rooms, i.e. SwitchRoom and PAC Room. The switch room would be directly above the pumpwell and wouldaccommodate the electrical and telemetry switch gear assembly. The Switch Room alsoprovides the access to the pumpwell and supports the monorail. The existing PAC plant at theWTP site would be relocated in the PAC room. The Switch Room would have two doors (1.2mand 2-3m wide) while the PAC Room would have a GI mesh front with a door made of similarmaterial. The building would be a brick building on reinforced concrete floor supported onconcrete piers founded on the bedrock.

Pipelines and trunnion

The designed pipe sizes are as follows.

Trunnion arm - DN300 Epoxy coated mild steel

Trunnion - DN250 Epoxy coated mild steel (alternative stainless steel)

Suction pipeline - DN300 - DICL

Delivery pipeline - DN250 DICL

A pressure sustaining valve should be provided in the rising main near the treatment plant.Concrete pits would be provided for the PAC injection and non return valves.

Costs

The estimated capital cost of the pumping station is $0.94M. The annual operation andmaintenance cost (excluding replacement cost) is $31,000 per annum.

Testing and commissioning

The existing raw water supply needs to be interrupted at various times for connection of thenew system to the existing infrastructure. It will be necessary to maintain the supply duringthe period of construction and installation of the new system.

It is therefore considered that the connection and installation should be carried out in amanner which will allow for a smooth change over before the old system is de-commissioned.


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8 Reference

Commerce, 2009 -1: Rylstone Water Supply System - Reticulation System Hydraulic

Analysis, A report prepared for Mid Western Regional Council by the Department ofCommerce, (Final Report, September, 2009).

Commerce, 2009 -2: Rylstone, Kandos and Villages Water Supplies Strategy Options Study,A report prepared for Mid Western Regional Council by the Department of Commerce, (April2009).


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APPENDICES


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Appendix 1

Preliminary Geotechnical Assessment


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Rylstone WS River Pumping Station

Preliminary Geotechnical Assessment

1. General

The site is located within rhyolitic tuff. Bouldery outcrop is evident throughout theslopes along the mains alignment and pumping station site. Bedrock crops outs in a

series of ledges on the slope leading to the creek and is exposed in the creek bed.

Generally the soil profile is very thinly developed. There is some fill along the suction

main alignment, especially in the vicinity of the dam where boulders appear to have

been placed. Some fill associated with the construction of the existing pump station

may also be expected on the upper slope leading to a levelled area adjoining the

building.

2. Pumping Station

At the pumping station site (borelog reference PS1 & PS2), bedrock was encounteredat depths of 0.14m/0.15m. In borehole PS1, the bedrock was cored between 0.14m to

6.01m. In borehole PS2, the TC bit penetrated the bedrock to a depth of 0.5m at which

point TC bit refusal was recorded.

The bedrock, within the depths of coring, is a rhyolitic tuff. The tuff is typically very

coarse grained with occasional medium grained interbeds and commonly includes

pebble-sized clasts.

The degree of weathering varies. The bedrock is moderately weathered to an

approximate depth of 1.2m and then becomes slightly weathered with rare moderately

weathered interbeds.

The rock sub-strength is assessed as very strong. For the three samples tested uniaxial

compressive strength ranged from 120 MPa to 146 MPa. The defect spacing ranges

from closely spaced in the upper 1m/1.4m and then becomes moderately widely

spaced to widely spaced.

The proposed 3.6m diameter well may need to be constructed by sinking a shaft.

Open excavation, due to the moderately steep slope leading to the creek, may not be

practical. Excavation in bedrock will be difficult due to high rock substance strength

and unfavourable defect spacing. A large excavator (30 tonne) with a rock breaker

will be needed in combination with blasting. Blasting will be required.

3. Suction Main

One borehole (M1) was cored adjacent to the existing building. Bedrock was

encountered at 0.86m depth. The bedrock is of similar type and quality to that

encountered in pumping station borehole PS1. Difficult excavation may expected.

Rock substance strength is also very strong. For two specimans tested, UCs test

yielded strengths of 99.5 MPa and 111 MPa. Blasting will be required.


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4. Rising Main

The rising main from the pump station to the connection point of the existing rising

main will traverse a moderate slope characterised by bouldery outcrop.

A total of four boreholes (M3-M6) were drilled on the slope. Generally, the soil

profile is thinly developed, ranging in thickness between 0.15m (M3) and 0.8m (M2).

The stratum is a silty sand with gravel, locally with traces of clay, organics or cobbles.

Rhyolitic tuff underlies this surficial horizon.

When first encountered the bedrock is extremely and highly weathered. This quality

bedrock extends to depths 0.6m (M3). 1,6m(M5) and 0.6m (M6). In borehole M4, the

TC bit refusal failed to penetrate the bedrock for any appreciable depth. TC bit

refusal, inferred to be in moderately weathered bedrock , was recorded at depths of

0.65m (M3) 0.7m (M4) and 0.6m (M6). Borehole M5 was terminated upon reaching

nominal target of 1.5m.

Excavation to TC bit refusal should be achieved using a large excavator. If

excavations below refusal levels are proposed then an assistance from a rock breaker

will be required. In area of outcrop, a rock breaker will be required.

Encl. Bore logs


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Appendix 2

Capital and O&M Cost Estimates


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Rylstone WS - River Pumping Station Created - 05Sep09Concept Design Cost Estimate Revised - 17Sep09

No Item Description Unit Quantity Rate Amount Total

1 Trunnion

Fabrication of trunnion & trunnion arm Item 1 $30,000 $30,000

Replace the trunnion (DN250) and arm (DN300) Item 1 $50,000 $50,000 $80,000

2 Suction Main

Supply & deliver DICLpipes (DN300 - SoxSp) m 103 $198 $20,394

Excavation and laying m 103 $137 $14,111

Extra over for rock excavation m3

131 $700 $91,700

Bedding m3

69 $85 $5,865

Backfilling m3

108 $35 $3,780

Concrete supports Nos 4 $2,500 $10,000

Connection to existing pipework near the dam Item 1 $12,535 $12,535 $158,385

3 Pumpwell

Site clearing Item 1 $5,000 $5,000

Excavation and dispose within site m3

12 $150 $1,800

Excavate in rock and dispose within site m3

91.0 $700 $63,700

R.C walls (cast-in-situ) m3

19 $2,000 $38,000

Base concrete incl.r/f & rock anchors (0.4m thick) m3

5.8 $2,000 $11,600

Cover (GI gratings) m2

4 $3,800 $15,200

Acceess platform Item 1 $12,500 $12,500

Access ladder m 9.5 $350 $3,325 $151,125

4 Pumpwell - PumpsPumping units Nos 2 $35,000 $70,000

Pipework within well (incl suction Tee) Item 1 $28,490 $28,490

GI davit Item 1 $4,500 $4,500

Allow for pump plinth, pipe brackets etc. Item 1 $5,000 $5,000

Dewatering pump and pipework Item 1 $12,000 $12,000

Ventilation system Item 1 $7,500 $7,500 $127,490

5 SCA & PAC Building (excluding PAC plant & accessories ) R/C columns (450x450) from bedrock including excavation m 26 $350 $9,100

Beams & slab for the building floor m3

27 $1,300 $35,100

Brickwork m2

102 $180 $18,360

Steel portal frame m 60 $250 $15,000

Roof m2

112 $35 $3,920

Door (1.2m wide) Nos 1 $2,400 $2,400

Door (3m wide) Nos 1 $4,200 $4,200

GI mesh for PAC room m2

$135 $0

Mono rails m 10 $450 $4,500Handrail for pumpwell m 15 $85 $1,275

Lighting Item 1 $5,000 $5,000

Rainwater down pipes m 18 $95 $1,710Retaining wall for access road next to main door exit (5m long) Item 1 $12,000 $12,000 $112,565

6 Del ivery Main

Supply & deliver DICLpipes (DN250 - SoxSp) m 71 $157 $11,147

Excavation and laying m 71 $127 $9,017

Bedding m3

43 $115 $4,945

Backfilling m3

26 $35 $910

Extra over for rock excavation m3

20 $750 $15,000

Concrete bulk heads Nos 10 $1,500 $15,000

PAC & valve pit Nos 2 $7,500 $15,000

Connection to existing rising main Item 1 $8,762 $8,762 $79,781

7 External pipework

Pump delivery pipes (DN200 double lines) Item 1 $27,314 $27,314 $27,314

8 Electrical & Telemetry

Electrical works Item 1 $85,000 $85,000

Lightening protector Item 1 $15,000 $15,000

Telemetry Item 1 $20,000 $20,000 $120,000

9 SUB TOTAL $856,659

10 Contingencies

Add 10% (of sub total) $85,666

TOTAL (INCLUDING GST) $942,325

Notes:

This estimate does not include:

1. Cost of temorary water supply arrangement

2. Access road

3. Relocation and installation of PAC plant and associated works

4. Power supply to site including new transformer and pole

5. Construction supervision cost

Costs for O&M cost calculations

M&E costs $305,400

Other costs $636,925


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Rylstone WS - River Pumping Station Created - 05Sep09

Concept design - Cost Estimate for pipework within pumpwell


1 Suction side (All DICL , supply price)

DN300 FlxSo Nos 1 $480 $480

DN300x300 Tee (all flanged) Nos 1 $950 $950

DN300 FlxFl 90 deg bends Nos 2 $500 $1,000

DN300 FlxFl pipe (0.55m long) Nos 1 $600 $600

DN300 FlxFl pipes 0.7m long Nos 2 $650 $1,300

DN300 butterfly valves Nos 2 $2,200 $4,400

DN300 FlxFl pipes 0.5m long Nos 2 $450 $900

DN300x200 Taper Nos 2 $480 $960 $10,590

2 Delivery side (All DICL - supply price)

DN150x200 Taper Nos 2 $460 $920

DN200 Thrust dismantling joint Nos 2 $2,300 $4,600

DN200 - FlxFl 90 deg bends Nos 4 $390 $1,560 DN200 - FlxFl pipe 4m Nos 2 $410 $820 $7,900

Sub Total $18,490

Delivery (10%) $1,849

Installation $10,000

Total ( for pipework within pumpwell) $28,490


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Concept design - Cost Estimate for pipework at the rising main (delivery main)


1 Connection to the existing rising main (All DICL)

DN250 couplings Nos 3 $685 $2,055

DN250 equal tee Nos 1 $810 $810

DN250 - FlxSp (1m long) Nos 2 $375 $750

DN250 pipe (1m) Nos 1 $350 $350

Sub Total $3,965

Delivery $397

Installation $3,500

Thrust block for the tee and valve $900

Total ( for connection of delivery main) $8,762


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Revised - 17Sep09

Concept design - Cost Estimate for pipework outside the pumpwell (dual lines)


1 DN200-DICL double lines from pumpwell wall

DN200 FlxSp pipes 1.8m long Nos 2 $350 $700

DN200 dismantling joints Nos 2 $490 $980

DN200 couplings Nos 2 $325 $650DN200 FlxFl NRV Nos 2 $3,500 $7,000

DN200 FlxSp pipes - 0.4m long Nos 2 $215 $430

DN200 - FlxFl bend (90deg) Nos 1 $380 $380

DN200 - FlxFl gate valves Nos 4 $1,800 $7,200

DN200 FlxFl pipes - 0.7m long Nos 3 $450 $1,350

DN200x200 Tee Nos 1 $475 $475

DN200 FlxFl pipes - 0.4m long Nos 4 $280 $1,120 $20,285

Sub Total $20,285

Delivery (10%) $2,028.5

Installation $5,000

Total ( for pipework outside pumpwell) $27,314


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Rylstone River Pumping Station - O&M Cost Calculations

Common inputs:

System capacity 5.28 ML/d

power cost 0.15 $/kwh =(15*5*0.2+0.1*(9*5+2*24))/(24*7)

Annual supply 500 ML

Pump head 23 m

ITEM DESCRIPTION Cost

$*1000

1 CAPITAL COSTS

Civil works 631

M&E Works 305.4

TOTAL CAPITAL COST 937

2 OPERATION AND MAINTENANCE COSTS

2.1 OPERATION COSTS

Power costs (pumps+other minor) 7.38 Add 10% to pump cost

Operator (4 hrs a week) 8.32 @40/hr

2.2 MAINTENANCE COSTS

Civil works (1% of capital cost) 6.31

M&E works (3% of capital cost) 9.16

3 REPLACEMENT COSTS

Not considered 0

TOTAL OPERATION & MAINTENANCE COSTS* $31,177 $/Year

[* Does not include PAC costs]

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