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CityLink Tulla WideningCityLink Melbourne Ltd23-Mar-2015

CityLink Tulla WideningHydraulic Assessment

AECOM CityLink Tulla Widening – Hydraulic Assessment

CityLink Tulla WideningHydraulic Assessment

Client: CityLink Melbourne Ltd

ABN: N/A

Prepared byAECOM Australia Pty LtdLevel 9, 8 Exhibition Street, Melbourne VIC 3000, AustraliaT +61 3 9653 1234 F +61 3 9654 7117 www.aecom.comABN 20 093 846 925

23-Mar-2015

Job No.: 60309955

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AECOM has prepared this document for the sole use of the Client and for a specific purpose, each as expressly stated in the document. No otherparty should rely on this document without the prior written consent of AECOM. AECOM undertakes no duty, nor accepts any responsibility, to anythird party who may rely upon or use this document. This document has been prepared based on the Client’s description of its requirements andAECOM’s experience, having regard to assumptions that AECOM can reasonably be expected to make in accordance with sound professionalprinciples. AECOM may also have relied upon information provided by the Client and other third parties to prepare this document, some of whichmay not have been verified. Subject to the above conditions, this document may be transmitted, reproduced or disseminated only in its entirety.


Quality InformationDocument CityLink Tulla Widening – Hydraulic Assessment

Ref 60309955

Date 23-Mar-2015

Prepared by Lisa Roach

Reviewed by Melanie Collett

Revision History

Revision RevisionDate Details

Authorised

Name/Position Signature

1 23-Mar-2015 Final Report Melanie Collett


Table of Contents1.0 Purpose 12.0 CityLink Tulla Widening Project 1

2.1 Scope 23.0 Methodology 14.0 Results 5

4.1 Flemington Road Interchange 54.1.1 Proposed Mount Alexander – Flemington Road Bridge over Ornamental Lake 54.1.2 Proposed Road Widening of Flemington Road Exit Ramp 6

4.2 Proposed Road Widening of Flemington Road Entry Ramp 75.0 Performance Criteria 9

AECOM CityLink Tulla WideningCityLink Tulla Widening – Hydraulic Assessment

P:\603X\60309955\6. Draft Docs\6.1 Reports\Hydraulics\CityLink Tulla Widening - Hydraulic Investigations -Ver1.docxRevision 1 – 23-Mar-2015Prepared for – CityLink Melbourne Ltd – ABN: N/A

1.0 PurposeThis report was commissioned by CityLink Melbourne Ltd (CML) to document the hydraulic investigationsundertaken in relation to any impacts of the CTW project, particularly from Dynon Road to Moreland Road, onMelbourne Water assets. The assessment is an initial analysis undertaken for Transurban to inform preliminarydesign and discussions with Melbourne Water. The design will be further developed by the Contractor and agreedwith Melbourne Water prior to construction.

This report provides:

- A summary of the proposed works that impact on Moonee Ponds Creek

- A description of hydraulic investigations undertaken

- An initial analysis on the extent of impacts to Melbourne Water assets

- Design criteria developed in consultation with Melbourne Water

2.0 CityLink Tulla Widening ProjectThe CTW project seeks to upgrade CityLink and the West Gate Freeway. The majority of the works are to deliveradditional traffic lanes within the existing road pavement. Where pavement widening occurs the majority of workswill be within the existing Declared Road boundary / CityLink lease boundary. In several areas widening outside ofthe road boundary / CityLink lease boundary will be required.

The CTW project works are inclusive of:

- pavement widening

- road barriers

- line marking and reconfiguration

- new structures for the Bell Street Ramp, Bell Street Collector Distributor, new Bridge on Mount AlexanderRoad, realignment, Bolte Bridge to West Gate Freeway entry ramp, and widening of the West Gate Freewayelevated structure west of Montague Street

- widening of existing bridges over Moonee Ponds Creek

- road signage and traffic management

- noise walls

- landscaping

- drainage works

- services relocations

- lighting

- Intelligent Transport Systems (ITS), road signage and traffic management including metered entry ramps.

Construction of the CTW project is planned to commence in mid-late 2015 and is expected to take approximatelytwo years.


2.1 ScopeThe majority of the works associated with the CTW project are contained within the existing pavement. Twolocations have been identified where road widening works affect Melbourne Water’s drainage assets. At all otherlocations, the works have been designed within the CityLink Lease Boundary and do not impact on MelbourneWater assets.

The locations of the works that affect Melbourne Water’s assets are identified in Figure 1 below. Within theseareas, AECOM conducted a hydraulic investigation to determine the impacts at:

- Area 1: Flemington Road Interchange

o Construction of a new bridge structure parallel to the existing Mount Alexander - Flemington RoadBridge, upstream of the existing Mount Alexander Road Bridge.

o Road widening of the Flemington Road exit ramp (southbound) and associated re-design of theornamental lake.

- Area 2: Flemington Road Entry Ramp

o Road widening of the Flemington Road entry ramp and construction of a retaining wall within theconcrete channel on the eastern bank of Moonee Ponds Creek.


Figure 1 Areas of impact on Melbourne Water assets

2

1


Area 1: Flemington Road Interchange

Figure 2 below shows the proposed works at the Flemington Road Interchange, which include:

- The new bridge structure parallel to the existing Mount Alexander - Flemington Road Bridge, upstream of theexisting Mount Alexander Road Bridge.

- Road widening of the Flemington Road exit ramp (southbound), which impacts the storage volume of theOrnamental Lake.

Figure 2 Proposed design of the ornamental lake with HEC-RAS chainages

Figure 3 shows the Ornamental Lake Moonee Ponds Creek looking upstream. Figure 4 shows the existing bridge(looking downstream from north of the Ornamental Lake). The new bridge is proposed to sit in the foreground,between the ornamental lake weir and the existing Flemington Rd bridges.


Figure 3 Ornamental Lake on Moonee Ponds Creek

Figure 4 Mount Alexander Road bridge over Moonee Ponds Creek (looking downstream from north of the bridge)


Area 2: Flemington Road Entry Ramp

Figure 5 and Figure 6 show the proposed works, which consist of road widening of the Flemington Road entryramp and construction of a retaining wall within the concrete channel on the eastern bank of Moonee PondsCreek, and the location of the HEC-RAS chainages on the design drawings.Figure 5 Moonee Ponds Creek with HEC-RAS chainages

Figure 6 Moonee Ponds Creek with HEC-RAS chainages

AECOM CityLink Tulla Widening – Hydraulic Assessment 1

3.0 MethodologyA HEC-RAS model that represents the existing conditions was provided by Maree Miscozzi (Melbourne Water) viaemail on Thursday 15th January 2015.

Area 1 - Flemington Road Interchange

For the Flemington Road Interchange a new existing conditions plan was created to include detailed survey in thevicinity of the Ornamental Lake. The bridge structure (as shown in Figure 7) was then included in this model withthe following properties:

- A five span structure with the four piers in line with the existing bridge, parallel to the direction of flow inMoonee Ponds Creek

- The bridge deck level and soffit level corresponding to the existing Mount Alexander Road bridge structure.

- To minimise the impact of the bridge on the ornamental lake, the piers on the upstream side of the bridgehave been set back from the edge of the structure (ie. The footpath section of the bridge is cantilevered).

Figure 7 HEC-RAS representation of the new Bridge over Moonee Ponds Creek

Area 2 - Flemington Road Entry Ramp

For the Flemington Road Entry Ramp the HEC-RAS model provided by Melbourne Water was used to determinethe existing cross section locations and flood levels. As the HEC-RAS model was not geo-referenced, the cross-section locations were measured from the upstream side of the Mount Alexander Road Bridge. The crosssections that were impacted by the proposed design were identified and the proposed encroachment measuredfrom the design drawings.

Table 1 shows the encroachments that were made for each of the impacted cross-sections. Theseencroachments (or offsets) were taken from the bottom of the left bank (looking downstream), and were modelledas levees in HEC-RAS. Figure 8 to Figure 17 show the cross sections with levees that were used in the proposeddeveloped conditions modelling.


Table 1 Impact of proposed design on HEC-RAS cross sections

HEC-RASChainage

Offset from bottomof left bank (m)

4225 3.234265 7.744285 8.284300 8.354305 8.294345 8.38

4394 9.04

4444 11.15

4494 11.82

4544 10.26

4594 10.11

Figure 8 Cross section at chainage 4171


-150 -100 -50 0 50 100 1502

3

4

5

6

7

8

9

Moonee Ponds Ck Plan: 1) Plan 07 21/01/2015 2) Des8 28/01/2015 CH420

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8

WS 100 Year - Plan 07

Ground

Levee

Bank Sta

.03 .016 .03

-150 -100 -50 0 50 100 1501

2

3

4

5

6

7

8

9

Moonee Ponds Ck P lan: 1) Plan 07 21/01/2015 2) Des8 28/01/2015 CH474 , Copy of CH460 adjusted down by [email protected]%=0.028m

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.028 .016 .028





-150 -100 -50 0 50 100 1502

3

4

5

6

7

8

9

Moonee Ponds Ck Plan: 1 ) Plan 07 21/01/2015 2) Des8 28/01/2015 CH 380

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03

-150 -100 -50 0 50 1002

3

4

5

6

7

8

9

Moonee Ponds Ck Plan: 1) Plan 07 21/01 /2015 2) Des8 28 /01/2015 CH 360

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03

-120 -100 -80 -60 -40 -20 0 20 40 602

4

6

8

10

12

Moonee Ponds Ck Plan: 1) Plan 07 21 /01/2015 2) Des8 28/01/2015 CH300

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03


Figure 13 Cross section at chainage 4394.83



0 10 20 30 40 502

3

4

5

6

7

8

9

Moonee Ponds Ck Plan: 1) Plan 07 21/01/2015 2 ) Des8 28/01/2015 SE040071_14

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03

0 10 20 30 40 50 602

3

4

5

6

7

8

9

10

Moonee Ponds Ck Plan: 1) Plan 07 21/01/2015 2 ) Des8 28/01/2015 SE040071_15

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03

0 10 20 30 40 50 602

3

4

5

6

7

8

9

10

Moonee Ponds Ck Plan: 1) Plan 07 21/01 /2015 2) Des8 28 /01/2015 SE040071_16

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03




4.0 Results

4.1 Flemington Road Interchange4.1.1 Proposed Mount Alexander – Flemington Road Bridge over Ornamental Lake

The inclusion of this bridge resulted in a 0.04 m increase in flood levels immediately upstream of the new bridge,as shown in Figure 18). This impact was reduced to zero just upstream of the new bridge within the ornamentallake.

The existing Mount Alexander Road Bridge over Moonee Ponds Creek has around 0.49m freeboard in the 1%AEP flood event at the lowest soffit. As the proposed bridge will tie into the existing Mount Alexander Road, thedeck levels of the two structures will be the same. Given the need to maintain the existing span distance, there islimited opportunity to reduce the structure depth of the proposed bridge. Based on the modelling that has beenundertaken, the new bridge will have a low chord (soffit level) of around 5.45m AHD. The predicted 1% AEPwater surface elevation for the proposed design case is 5.27m AHD upstream of this bridge. This results inapproximately 0.18 m of freeboard at the upstream edge of the structure.

It is noted that the bridge design will be further developed by the Contractor and agreed with Melbourne Waterprior to construction.

0 10 20 30 40 50 602

3

4

5

6

7

8

9

10

Moonee Ponds Ck P lan: 1) Plan 07 21/01/2015 2) Des8 28/01/2015 SE040071_17

Station (m)

Ele

vatio

n(m

)

Legend


WS 100 Year - Des8

Ground

Levee

Bank Sta

.03 .016 .03

0 10 20 30 40 50 602

4

6

8

10

12

Moonee Ponds Ck P lan: 1) Plan 07 21/01/2015 2) Des8 28/01/2015 SE040071_18

Station (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - Des8


Ground

Levee

Bank Sta

.03 .016 .03


Figure 18 HEC-RAS results showing the impact of the new Bridge over Moonee Ponds Creek

4.1.2 Proposed Road Widening of Flemington Road Exit Ramp

Widening the Flemington Road exit-ramp will reduce the volume of the Ornamental Pond in the 1% AEP floodevent (refer to Figure 19). Melbourne Water advised that this pond has an important flood storage role onMoonee Ponds Creek, and that the current flood storage volume must be maintained. The pond currently storesapproximately 34,000 m3 in the 1% AEP flood event (based on the flood levels from the HEC-RAS model). Apreliminary estimate indicated that the proposed design resulted in a loss of approximately 1,500 m3 of storagevolume for this event.

Figure 19 shows the revised design of the ornamental lake in this section. The additional storage volume hasbeen achieved by introducing a retaining wall around the whole lake, rather than the existing sloped batters. Thesection between the edge of the lake and the bottom of the retaining wall will be just above the permanent poollevel of the lake, and will be landscaped, to maintain the current look of this area.

The inclusion of these changes results in minor changes to flood levels within the Ornamental Lake, initially anafflux of 0.04m for a short distance then reducing to an afflux of 0.01m for the majority of the lake. At the locationof the Travencore Development (CH 3790), the HECRAS model currently depicts a small increase in watersurface elevation, however it is noted that the existing conditions model produces an unstable water surfaceprofile in this location and as such the absolute water level is not recommended for assessment of design criteria.Instead, the energy grade elevation which is reduced at this location by 0.2m has been assessed against thedesign criteria. Further upstream of the lake (CH 3825 and onwards), a reduction in the 1% AEP peak flood levelsis exhibited.

It is noted that the bridge design will be further developed by the Contractor and agreed with Melbourne Waterprior to construction.

3700 3800 3900 4000

1

2

3

4

5

6

Moonee Ponds Creek T U Plan: 1) MW Exist mod 23/02/2015 2) Des32 23/02/2015

Main Channel Distance (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - MW Exist mod

WS 100 Year - Des32

Ground

MP Stage 1 MP Stage 1


Figure 19 Impact of original design on the Ornamental Lake

4.2 Proposed Road Widening of Flemington Road Entry RampFigure 20 shows a long section of the modelled water surface elevation in Moonee Ponds Creek for the existingand proposed development conditions. This shows that there is minimal impact predicted through thisdevelopment.

Table 2 shows the results from the HEC-RAS model. This includes the existing and proposed development watersurface elevation and velocities. The maximum impact on water surface elevation is modelled as 0.01m, with themaximum change in velocity being 0.03 m/s. These values are within the design criteria established inconsultation with Melbourne Water and do not require mitigation works.Figure 20 Long section of Moonee Ponds Creek showing existing and proposed Water Surface Elevations for the 100 year ARI flood

event

3600 3800 4000 4200 4400 4600 4800

1

2

3

4

5

6

Moonee Ponds Creek TU P lan: 1) MW Exist mod 23/02/2015 2) Des32 23/02/2015

Main Channel Distance (m)

Ele

vatio

n(m

)

Legend

WS 100 Year - MW Exist mod

WS 100 Year - Des32

Ground

MP Stage 1 MP Stage 1


Table 2 Impact of proposed design on Water Surface Elevations in Moonee Ponds Creek

Existing ModifiedExisting*

Developed Difference (Developed- Modified Existing)

RiverSta

W.S.Elev

Vel Chnl W.S. Elev Vel Chnl W.S. Elev Vel Chnl W.S. Elev Vel Chnl

(m) (m/s) (m) (m/s) (m) (m/s) (m) (m/s)5127 9.08 2.97 9.08 2.97 9.08 2.97 0 0

5092 8.56 4.27 8.56 4.27 8.56 4.27 0 0

5043 8.09 5.03 8.09 5.03 8.08 5.04 -0.01 0.01

5018 7.96 5.03 7.96 5.03 7.97 5.03 0.01 0

4993 7.09 4.51 7.09 4.51 7.1 4.5 0.01 -0.01

4972 6.95 3.6 6.95 3.6 6.95 3.6 0 0

4943 7.06 3.02 7.06 3.02 7.06 3.02 0 0

4893 6.76 3.68 6.76 3.68 6.76 3.67 0 -0.01

4843 6.73 3.52 6.73 3.52 6.73 3.51 0 -0.01

4794 6.71 3.36 6.71 3.36 6.72 3.35 0.01 -0.01

4744 6.29 4.19 6.29 4.19 6.28 4.21 -0.01 0.02

4694 6.17 3.97 6.18 3.94 6.18 3.96 0 0.02

4644 6.09 3.96 6.1 3.93 6.09 3.95 -0.01 0.02

4594 6.04 3.81 6.06 3.78 6.05 3.8 -0.01 0.02

4544 6 3.68 6.02 3.64 6.01 3.67 -0.01 0.03

4494 5.94 3.64 5.96 3.6 5.95 3.61 -0.01 0.01

4445 5.88 3.61 5.91 3.56 5.9 3.57 -0.01 0.01

4395 5.85 3.45 5.89 3.39 5.88 3.4 -0.01 0.01

4345 5.93 2.93 5.96 2.89 5.95 2.9 -0.01 0.01

4285 5.92 2.79 5.95 2.76 5.94 2.77 -0.01 0.01

4265 5.92 2.69 5.95 2.66 5.95 2.67 0 0.01

4225 5.91 2.62 5.95 2.59 5.94 2.6 -0.01 0.01

4171 5.9 2.55 5.93 2.51 5.92 2.52 -0.01 0.01

*Model includes feature survey at the location of the Ornamental Lake


5.0 Performance CriteriaThe modelling undertaken for the CTW project shows that at each of these locations minimal hydraulic impactsare predicted. The findings contained in this report are based on an initial analysis of the preliminary design. Thishas informed discussions with Melbourne Water about how the proposed solution could be able to meetMelbourne Water’s design criteria. Using this information and in consultation with Melbourne Water the followingdesign performance criteria have been developed. During the detailed design phase all proposed works affectingMoonee Ponds Creek and the Ornamental Lake would be evaluated in accordance with these design criteria:

- No increase in flood level at the Travencore Development (between cross Section 3790 and 3845 in the MWModel) for the 100 year ARI flood event

- No change in permanent pool levels for the ornamental lake

- A maximum increase in flood levels of 0.03m for Moonee Ponds Creek in the 100 year ARI flood event anddissipated within 50m

- The soffit levels of the new Mt Alexander Road bridge across the Moonee ponds Creek, must match orexceed the existing structural soffit level of the Mt Alexander Road bridges over Monee Ponds Creek. Non-structural elements currently fixed under the bridge (such as piped services) should not be assumed as afixed soffit for example.

- Maintain the existing functionality of maintenance access (permanent state)

- Maintain the existing functionality of Shared Use Path access (permanent state)

- Maintain the current level of protection and height of the wall for the existing shared path under the MountAlexander Road Bridge

- Optimising the opportunities for vegetated and ‘soft engineered’ treatments to all surfaces where practical

- Hydraulic modelling will be undertaken in HEC-RAS and updated model provided to Melbourne Water at theconclusion of the Works

- Generally, landscape and aesthetic treatments will aim to be sympathetic with the more recent CityLinkinfluences.

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