appendix h hydrology and hydraulic assessment...3.2 afflux 6 3.3 waterway structure blockage 6 3.4...

21-20687/176626

Schofields Road Upgrade: Tallawong Road to Veron Road Review of Environmental Factors

Appendix H

Hydrology and Hydraulic Assessment

April, 2012

NSW Roads and Traffic Authority

2113134A-HY-PR-026-C

Schofields Road Upgrade Stage 2: Tallawong Road to Veron Road Hydrology and Hydraulic Assessment

Parsons Brinckerhoff Australia Pty Limited ABN 80 078 004 798

Ernst & Young Centre, Level 27, 680 George Street Sydney NSW 2000 GPO Box 5394 Sydney NSW 2001 Australia Telephone +61 2 9272 5100 Facsimile +61 2 9272 5101 Email [email protected] NCSI Certified Quality System ISO 9001

Schofields Road Upgrade Stage 2: Tallawong Road to Veron Road

Hydrology and Hydraulics Assessment

PARSONS BRINCKERHOFF 2113134A-HY-PR-026 Page i

Contents

Page Number

1. Introduction .................................................................................................................................... 1 1.1 Background 1 1.2 Scope of this report 1 1.3 Study objectives 1 1.4 Available data 1 1.5 Referenced documents 2

2. North West Growth Centre Precincts ............................................................................................ 3 2.1 Alex Avenue Growth Centre Precinct 4 2.2 Riverstone Growth Centre Precinct 4 2.3 Schofields Growth Centre Precinct 4 2.4 Blacktown City Council Growth Centre Precincts – Development Control Plan (2010) 4 2.5 Alex Avenue and Riverstone Growth Centre Precinct – post-exhibition technical studies 4

3. Design criteria ................................................................................................................................ 6 3.1 Schofields Road flood immunity 6 3.2 Afflux 6 3.3 Waterway structure blockage 6 3.4 Climate change 6 3.5 Future catchment development 7 3.6 Construction staging 7 3.7 Water quality 7 3.8 Working in creeks 7 3.9 Local water authority and stakeholders 7

4. Study area ....................................................................................................................................... 8 4.1 Location 8 4.2 Climate 8 4.3 Catchment descriptions 8

4.3.1 Railway Terrace tributary of Eastern Creek – No.1 8 4.3.2 Railway Terrace tributary of Eastern Creek – No. 2 9 4.3.3 First Pond Creek 9 4.3.4 First Ponds Creek tributary 9

5. Review of previous investigations .............................................................................................. 10 5.1 Upgrade of Garfield Road and Schofields Road from Richmond Road to Windsor Road – Stage 1 Assessment of Flood Impacts (Lyall & Associates 2008) 10 5.2 Report for Schofields Road Concept Design – Creek Crossing Preliminary Design Report (GHD 2010a) 10 5.3 Report for Riverstone and Alex Avenue Precincts Post Exhibition Flooding and Water Cycle Management (GHD 2010b) 10

6. Hydrologic investigation.............................................................................................................. 12 6.1 Catchment parameters 12 6.2 Rainfall intensity frequency duration parameters 13 6.3 Extreme event calculation 13 6.4 Adoption of existing hydrological models 14 6.5 Peak flows 14 6.6 Comparison of previous studies 15

7. Hydraulic analysis ........................................................................................................................ 16 7.1 Adoption of pervious investigation hydraulic models 16 7.2 Cross-sections 16 7.3 Manning's roughness coefficients 16 7.4 Adoption of pervious investigation hydraulic models 17 7.5 Existing conditions 17

7.5.1 Existing hydraulic structures 17 7.5.2 Unsteady flow data 17

7.6 Proposed condition 18



PARSONS BRINCKERHOFF 2113134A-HY-PR-026 Page ii

7.6.1 Riparian corridor assessment 18 7.6.2 Proposed hydraulic structures 18

7.7 Modelling results 19 7.7.1 100-year ARI event modelling results 19 7.7.2 Extreme event modelling results 20 7.7.3 Proposed structure results 21 7.7.4 Climate change impacts on proposed bridges 22

8. Recommendations/mitigations.................................................................................................... 23

9. Statement of limitations ............................................................................................................... 24

List of tables Table 6-1 Schofield Road watercourse crossings catchment parameters 12 Table 6-2 Schofields Road IFD parameters 13 Table 6-3 Schofields Road catchments PMP calculation parameters 14 Table 6-4 Schofields Road Upgrade – watercourse crossings peak flows 14 Table 6-5 Hydrological comparison with previous studies 15 Table 7-1 Hydraulic model Manning’s ‘n’ values 16 Table 7-2 Existing crossing structures 17 Table 7-3 Riparian corridor requirements 18 Table 7-4 Proposed crossing structures 18 Table 7-5 100-year ARI water level and afflux results 19 Table 7-6 Extreme event water level results 21 Table 7-7 Proposed structure results 21 Table 7-8 Climate change peak flood level results at proposed structures 22 List of figures Figure 1: North West Growth Centre Precincts (DoP 2011) 3 List of appendices Appendix A Supporting Hydrologic Data Appendix B Supporting Hydraulic Data Appendix C Minutes of Meetings



PARSONS BRINCKERHOFF 2113134A-HY-PR-026 1

1. Introduction

1.1 Background The Roads and Maritime Services propose to upgrade and extend Schofields Road, located in Sydney NSW, in three separate stages. This report is associated with Stage 2 of the upgrade of Schofields Road from Tallawong Road to Veron Road.

Schofields Road upgrade Stage 2: Tallawong road to Veron Road (referred to as The Proposed Upgrade in this report) crosses a number of watercourses. A range of bridges and culverts are proposed for the upgrade as structures for crossing watercourses. The watercourses crossing the proposed upgrade generally flow north and drain to the Hawkesbury River, which lies approximately 13 km north of the proposed upgrade.

1.2 Scope of this report This report provides a hydrologic and hydraulic assessment of the major watercourse crossings of Schofields Road upgrade – Stage 2: Tallawong Road to Veron Road to support the review of environmental factors (REF); it is based on the concept design of the proposed upgrade.

1.3 Study objectives The objectives of this study are to:

Describe existing flood conditions at the watercourse crossing points for the proposed upgrade and establish the base line conditions for the proposed crossing structures.

Identify structures and properties that may be affected by flooding because of the proposed upgrade.

Assess the impacts of the proposed crossing structure on:

flood levels upstream and downstream of the project works

flow velocities upstream and downstream of the project works.

Provide recommendations for the proposed crossing structures for each watercourse and drainage line crossings of the proposed upgrade.

This study has been conducted in accordance with the Alex Avenue and Riverstone Growth Centre Precinct Development Control Plan (Blacktown City Council 2010) and guidance in Australian Rainfall and Runoff (Engineers Australia 2001).

1.4 Available data The following data were used in this flood study:

1: 25,000 topography maps for Blacktown City Council (Land Information Centre NSW 1978). 1: 25,000 topography maps for Blacktown City Council

detailed survey (2011)

laser survey (supplied by Blacktown City Council August 2011)




20% Concept Road Design

Preliminary Creek Crossing Report (GHD February 2010)

Preliminary Creek Crossing RAFTS Hydrological modelling (supplied by GHD)

Preliminary Creek Crossing MIKE 11 Hydraulic Model (supplied by GHD).

1.5 Referenced documents This report has been designed in accordance with the following documents:

Pilgrim, D H (ed.) first published 1987, reprinted 1998, Australian Rainfall and Runoff, Engineers Australia, Canberra.

NSW Road and Traffic Authority, Road Design Guide, NSW Road and Traffic Authority, Sydney.

Flavell, D (ed.) 1994, Waterway Design – A Guide to the Hydraulic Design of Bridges, Culverts and Floodways, AUSTROADS, Sydney.

Bureau of Meteorology 2003, The Estimation of Probable Maximum Precipitation in Australia: Generalised Short-Duration Method, Australian Government, Canberra.

NSW Fisheries, 2003, Policy and Guidelines for Fish Friendly Waterway Crossings, NSW Fisheries, NSW Department of Primary Industries, Sydney.

Fairfull, S & Witheridge, G, 2003, Why Do Fish Need to Cross the Road? Fish Passage Requirements for Waterway Crossings, NSW Fisheries, Cronulla.

NSW Road and Traffic Authority 2011, Draft Climate Change Adoption Policy – Rainfall intensity and Flood estimation, Sydney.

The following documents are referenced in this report:

Blacktown City Council 2005, Engineering Guide for Development, Blacktown Council, Sydney.

Blacktown Council 2006, Development Control Plan – Appendix R – Water Sensitive Urban Design and Integrated Water Management, Sydney.

Department of Planning 2010, Growth Centre Precinct Development Control Plan, Sydney.

Lyall and Associates 2008, Upgrade from Garfield Road and Schofields Road from Richmond Road to Windsor Road – Stage 1 Assessment of Flood Impacts, Sydney.

GHD 2010a, Report for Schofields Road Concept Design – Creek Crossing Preliminary Design Report, Sydney.

GHD 2010b, Report for Riverstone and Alex Avenue Precincts Post Exhibition Flooding and Water Cycle Management, Sydney.




2. North West Growth Centre Precincts The New South Wales Department of Planning (DoP) established the North West Growth Centre in 2005. The North West Growth Centre is approximately 10,000 ha of planned development within the local government area (LGA) boundaries of Baulkham Hills, Blacktown and Hawkesbury. It will be supported by a major centre at Rouse Hill and will contain about 70,000 new dwellings. It is made up of 16 ‘growth centre precincts’, which are areas that will be released progressively over the next 30 years. The Sydney growth centre website contains information on the proposed growth centre precincts (www.gcc.nsw.gov.au).

Figure 1: North West Growth Centre Precincts (DoP 2011)

The proposed upgrade of Schofields Road – Stage 2 Talllawong Road to Veron Road forms the border between two main growth centre precincts and bisects one growth centre precinct, all of which are located within Blacktown City Council LGA.

A full development control plan (DCP) was devised for the growth centres located within the Blacktown City Council LGA. The existing DCP covers the Alex Avenue and Riverstone Growth Centres; an update is due to be released in the near future to incorporate the Schofields Growth Centre Precinct.

A Flooding and Water Cycle Management Plan (GHD 2010b) was developed for the Alex Avenue and Riverstone Precincts as part of the technical support documents to the DCP. The plan details the hydrological and hydraulic investigations made as part of the DCP development.

This section gives a brief description of each growth centre precinct and the DCP documents from a hydrology and hydraulics point of view.




2.1 Alex Avenue Growth Centre Precinct Alex Avenue Growth Centre Precinct lies to the south of the proposed upgrade of Schofields Road between the junctions of Schofields Road and Tallawong road and Schofields Road and Railway Terrace. It will mainly contain residential and commercial developments, with provision for around 6,300 dwellings, 25,000m2 of retail space and two new schools within its 420 ha.

The precinct includes the entire catchment draining towards Schofields Road, including First Ponds Creek and the Railway Terrace tributary of Eastern Creek.

2.2 Riverstone Growth Centre Precinct Riverstone Growth Centre Precinct lies to the north of the proposed upgrade of Schofields Road from Tallawong road to Railway Terrace. Its 975 ha will mainly contain residential and commercial developments, with provision for around 9,000 dwellings, 57 ha of conservation reserve and four new schools.

The precinct contains the receiving catchments downstream of Schofields Road between Tallawong Road and Railway Terrace.

2.3 Schofields Growth Centre Precinct Schofields is part of the ‘Second Release’ precincts in the North West Growth Centre and is located west of Railway Terrace. The proposed upgrade of Schofields Road bisects this precinct, which incorporates the upstream catchments to the south and also extends north of the proposed upgrade to Eastern Creek.

2.4 Blacktown City Council Growth Centre Precincts – Development Control Plan (2010) The DCP details specific guidelines for development in each growth centre precinct released in the LGA. Section 2.3.1 of the DCP details the water cycle management controls that are prescribed for the precincts.

The main control that affects this project is the control of a full regional stormwater detention strategy, which will maintain the existing hydrological regime despite the change in landform because of the growth centre precinct plan. The regional stormwater detention plan will reduce the developed peak flow to pre-development flows through incorporating stormwater detention and management devices within the development. The regional stormwater detention scheme will be designed and managed by Blacktown City Council.

Full details of the DCP are available on the Department of Planning Growth Centre website (www.gcc.nsw.gov.au).

2.5 Alex Avenue and Riverstone Growth Centre Precinct – post-exhibition technical studies The Flooding and Water Cycle Management Plan (GHD 2010b) details all the hydrological, hydraulic and water quality investigations for the growth centre precincts. The full technical documents are available on the growth centre website (www.gcc.nsw.gov.au/alexave).




The plan has considered climate change by increasing rainfall intensity by 20 % in a sensitivity analysis of the hydrological designs. The effect of this increase was reviewed and the ability of the proposed stormwater management system to adapt to climate change was assessed. This approach is generally in line with the Roads and Maritime Services policy adopted for this project, climate change is discussed in detail in Section 3.4. The Department of Planning has agreed to supply the RTA with all hydrologic and hydraulic models used for the Alex Avenue Development Control Plan to ensure comprehensive and integrated design is achieved for the area.

A full review of the precinct plan and associated technical documents has been made and appropriate design criteria have been selected for the proposed upgrade, Full details of the design criteria are detailed in Section 3.




3. Design criteria The objective of the watercourse crossings for the proposed upgrade is to minimise the flooding impacts to the creek from afflux (change in water levels from the existing conditions to the proposed condition). Other criteria for the creek crossings, such as fish passage and riparian corridors, must also be addressed in the design. As such, the following design criteria have been established:

3.1 Schofields Road flood immunity The watercourse crossing infrastructure has to be sized so that the proposed upgrade is immune from flooding in a 100-year ARI event.

3.2 Afflux Where possible, zero afflux at each of the proposed watercourse crossings is required. As zero afflux may not be possible at all locations because of topography, or other unavoidable constraints, it is proposed that any increase in flood level must not encroach on land zoned for development in the upstream and downstream growth centre precincts, as outlined in Section 2.

3.3 Waterway structure blockage A 50% transverse drainage blockage factor is applied to all culvert inlets for this project.

Blacktown City Council requires a 50% blockage factor applied to culvert design as described in the Growth Centre Precinct DCP.

An allowance is made for blockage by designing transverse culverts to achieve zero afflux without blockage. The culvert opening area (or number of culvert cells) is then increased by 50% to account for the blockage factor. This methodology is stipulated by Blacktown City Council and has been applied to this project for consistency.

3.4 Climate change The potential effect of climate change on the proposed upgrade will be assessed as detailed in the Roads and Maritime Services document Draft Climate Change Adoption Policy – Rainfall intensity and Flood Estimation (RTA 2011).

It is the Roads and Maritime Services policy to manage any increases in rainfall intensity predicted by climate change through a sensitivity analysis.

General drainage and bridge design procedures and afflux analysis will use the current version of Australian Rainfall and Runoff (ARR) and other applicable design guides. A 20% increase in rainfall intensity is proposed in a sensitivity analysis of the design, which meets the requirements of the growth centre precinct and the Roads and Maritime Services Climate Change Policy.




3.5 Future catchment development Blacktown City Council has adopted a regional onsite detention policy as part of the Alex Avenue Precinct Development Control plan (Department of Planning 2010). This on-site detention policy will maintain the existing flow regime in the catchment by providing stormwater detention basins in strategic locations throughout the Alex Avenue catchment.

As a result of the onsite stormwater detention policy adopted in the Blacktown City Council Growth Centres DCP, it is assumed the existing hydrologic regimes in the upstream catchments are retained during the development of the growth centre precincts for all events up to and including a 100-year average recurrence interval (ARI) event.

For events rarer than a 100-year ARI event (2000 and Probable Maximum Precipitation –PMP), full catchment development has been assumed, as the on-site detention systems will overflow in these events.

3.6 Construction staging To ensure positive drainage at all times, constructing staging of the proposed upgrade has been assessed in the Schofields Road Upgrade – Stage 2, Tallawong Road to Veron Road Concept Design report 2113134A-GN-PR-027.

3.7 Water quality Water quality and treatment are considered in the Schofields Road Upgrade – Stage 2, Tallawong Road to Veron Road Concept Design report (2113134A-GN-PR-027).

3.8 Working in creeks Working in creeks will be required for culvert and bridge construction, fish passage construction and creek realignment. Safe working in creeks should adhere to NSW Fisheries Policy and Guidelines for Fish Friendly Waterway Crossings (2033), and Fairfull, S & Witheridge, G Why Do Fish Need to Cross the Road? (2003) (see Section 1.5 for references).

3.9 Local water authority and stakeholders Recommendations of appropriate mitigation and management measures will take into account the requirements of the Hawkesbury-Nepean Catchment Management Authority. Liaison with stakeholders shall take place to assess the appropriateness of the hydrological and hydraulic design. Minutes of meetings with stakeholders are included in Appendix C.




4. Study area

4.1 Location Schofields Road is an existing two-lane, two-way rural road between Railway Terrace at Schofields and Windsor Road at Rouse Hill. The existing Schofields Road runs east-west between Windsor Road in the east and Railway Terrace in the west. The road transitions immediately on its eastern entrance from a commercial-residential area to a rural residential area.

The general catchments near Schofields Road drain in a northern direction across Schofields Road, ultimately to the Hawkesbury River about 14 km to the north.

Four main watercourse catchments drain towards the proposed upgrade, as shown in Figure A1, included in Appendix A. The watercourse crossings are named as the following for the purposes of this assessment:

Railway Terrace Tributary of Eastern Creek Tributary – No.1 (CH 4650)

Railway Terrace Tributary of Eastern Creek Tributary – No.2 (CH 4500)

First Ponds Creek (CH 2800)

First Ponds Creek Tributary (CH2500)

A number of minor drainage line crossings are also proposed for this project. They are detailed in the Stage 2 Schofields Road Upgrade – Concept Design Report (2113134A-GN-PR-027).

This report mainly focuses on the detailed hydrological and hydraulic investigations for the watercourse crossings listed above.

4.2 Climate The average annual rainfall for Schofields region is approximately 910 mm a year, which is based on 58 years of rainfall data recorded at the Bureau of Meteorological Station (BoM) No. 067026, located at Seven Hills (Collins Street research station). The climate is characterised by warm to hot summers and cool to cold winters, and rainfall is summer/autumn dominant.

4.3 Catchment descriptions This section gives a brief description of the proposed watercourse crossing points for the proposed upgrade. Catchment maps for each waterway crossing are included in Appendix A.

4.3.1 Railway Terrace tributary of Eastern Creek – No.1

This crossing is located at about CH4650m, and has a catchment area of about 100.5 ha that is upstream of the proposed upgrade. The catchment is largely semi-urban acreages, with a high proportion of clearing. The area directly south of the proposed upgrade is relatively uncleared, as is the creek line.




The catchment drains the majority of the western side of the Alex Avenue Precinct, with Railway Terrace to the west Burdekin Road to the south and Alex Avenue to the west forming the catchment borders upstream of the proposed upgrade.

Downstream of the proposed upgrade, the creek flows through some residential properties, forming the boundary between them. The creek then turns west before it passes under Railway Terrace and the Richmond Rail Line then enters a stormwater network under an existing residential development located within the proposed Schofields precinct. The stormwater network discharges to an open channel about 2 km upstream of its confluence with Eastern Creek.

4.3.2 Railway Terrace tributary of Eastern Creek – No. 2

This crossing is located at about CH4500m on the Schofields Road Upgrade and has a catchment area of about 20.1 ha upstream of the proposed upgrade. The catchment is largely semi-urban acreages, with a high proportion of clearing. The area directly south of the crossing point is relatively uncleared, as is the creek line. North of the proposed upgrade, the creek flows through several residential properties, forming the boundary between them. This creek line joins with the Railway Terrace Tributary of Eastern Creek – No.1 about 1 km downstream of the proposed upgrade.

4.3.3 First Pond Creek

The proposed upgrade crosses First Ponds Creek at approximately CH2800m, and has a catchment area of about 218.4 ha upstream of the proposed upgrade. The catchment is largely semi-urban acreages, with a high proportion of clearing.

The catchment drains the majority of the eastern side of the Alex Avenue Precinct, with Alex Avenue to the west, Burdekin Road to the south and Ridgeline Drive to the east forming the catchment borders upstream of the proposed upgrade.

This creek forms the boundary to a number of residential properties in the Schofields Road area. Downstream of Schofields Road, the Creek flows northwards and joins the Hawkesbury River about 14 km north of the Schofields Road crossing.

4.3.4 First Ponds Creek tributary

This crossing is located at approximately CH2500 on the Schofields Road Upgrade. It has a relatively small catchment area of about 38.1 ha upstream of the proposed upgrade.

The catchment drains the eastern side of the Alex Avenue Precinct, with Hambledon Drive to the west and Greenview Parade to the south and Ridgeline Drive to the west forming the catchment borders upstream of the proposed upgrade

This creek line joins with First Ponds Creek about 1 km downstream of the proposed upgrade.




5. Review of previous investigations Several studies were made previously of this study area as part of projects and plans commissioned by Blacktown City Council and Roads and Maritime Services.

They will be used as a check on the hydrological, hydraulic and water quality modelling used for this project. Previous flood studies in the area of relevance to this project are summarised below.

5.1 Upgrade of Garfield Road and Schofields Road from Richmond Road to Windsor Road – Stage 1 Assessment of Flood Impacts (Lyall & Associates 2008) Lyall and Associates made a hydrological review of the propose upgrades of Garfield and Schofields Roads in 2008. The review discusses the likely crossings at the watercourse crossings at Railway Terrace Tributary and Eastern Creek Tributary.

As no survey data was available when Lyall and Associates developed its study, no minor culvert crossings were identified; however, the report noted it was likely there would be a number of these minor crossings.

5.2 Report for Schofields Road Concept Design – Creek Crossing Preliminary Design Report (GHD 2010a) Roads and Maritime Services made a preliminary creek crossing study for the proposed upgrade of Schofields Road (GHD 2010a). It covered the three stages of the Schofields Road upgrade from the existing junction at Windsor Road and extended east to a new junction with Richmond Road. The study detailed investigations at locations for four watercourse crossings and one minor drainage line crossing in the Stage 2 area of Schofields Road upgrade, including Railway Terrace Tributary of Eastern Creek no. 1 and 2, First Ponds Creek, First Ponds Creek Tributary and one other minor drainage crossing.

A riparian corridor study was also part of this investigation, which specified a range of minimum riparian corridor widths to be retained and depicted the watercourse crossing structure widths at the Railway Terrace and First Ponds Creek bridge locations. The riparian corridor is further discussed in Section 7.6.1.

5.3 Report for Riverstone and Alex Avenue Precincts Post Exhibition Flooding and Water Cycle Management (GHD 2010b) The Department of Planning made a full hydrological assessment of the proposed Alex Avenue and Riverstone Precincts to determine the impact of the growth centre precincts on the existing hydrological regime in the area (GHD 2010b). It presented a conceptual design for a regional stormwater runoff detention system to reduce the stormwater runoff to existing levels in both precincts.

This study discusses the water quality treatment measures developed to meet the Blacktown City Council Growth Centre Precincts DCP.




As the report does not include any data or results from the hydrological modelling, the detention system could not be tested or reviewed in detail; however, the Department of Planning has agreed to supply the hydrological models used in this study to the Roads and Maritime Services, at detailed concept design stage, to ensure an integrated design for the proposed upgrade.




6. Hydrologic investigation This section discusses the hydrological investigations made for the waterway crossings detailed in this study.

Hydrologic models simulate rainfall-runoff processes within catchments. They are used to estimate catchment flows generated from either design storm events or historical rainfall records.

Hydrologic models represent catchments and their tributaries as a series of sub-catchment areas, based on watershed boundaries, which are linked together to replicate the stream network. The model input data include parameters to represent factors, such as rainfall patterns (temporal and spatial), catchment size, catchment slope, drainage features, channel and floodplain storage, and variations in catchment land use.

Hydrological modelling software suitable for design flood estimation is described in Australian Rainfall and Runoff (Pilgrim 1998). Examples of commonly used models include XP-RAFTS, RORB and WBNM.

The XP-RAFTS model converts rainfall to runoff by applying rainfall losses to both the impervious and pervious catchments within the model to produce effective rainfall hyetographs.

6.1 Catchment parameters Catchment parameters, such as slopes, flow path lengths and sub-catchment areas, were defined using 1:25000 topographic maps and the Blacktown City Council laser survey of the surrounding area. Notes and photographs taken during the field investigations and aerial photographs were used to determine other catchment parameters, including percentage impervious and catchment roughness values.

Loss parameters were adopted based on recommendations within Australian Rainfall and Runoff (2001) and the XP-RAFTS user manual. Details of XP-RAFTS model input parameters adopted are detailed in Table 6-1.

Table 6-1 Schofield Road watercourse crossings catchment parameters

catchment Area (ha)

Manning's n

% Impervious

Initial loss (mm) Continuing loss (mm/hr)

Railway Terrace Tributary – No. 1

100.5 0.06 30 15.0 (pervious)

2.5 (impervious

2.0 (pervious)

0.0 (impervious)


21.1 0.06 30 15.0 (pervious)

2.5 (impervious

2.0 (pervious)

0.0 (impervious)

First Ponds Creek 218.4 0.06 30 15.0 (pervious)

2.5 (impervious

2.0 (pervious)

0.0 (impervious)

First Ponds Creek tributary

38.1 0.06 30 15.0 (pervious)

2.5 (impervious

2.0 (pervious)

0.0 (impervious)




6.2 Rainfall intensity frequency duration parameters Rainfall intensity frequency duration (IFD) parameters were obtained from Australian Rainfall and Runoff, Volume 2 (Engineers Australia 1987, 2001) and were input into the hydrological calculations for the Schofields Road Upgrade catchments. IFD parameters used are shown in Table 6-2. Details of the IFD calculations are included in Appendix A.

Table 6-2 Schofields Road IFD parameters

AR&R reference Variable Value

Map1.7 2I1 30.64

Map2.7 2I12 6.85

Map3.7 2I72 1.94

Map4.7 50I1 59.00

Map5.7 50I12 13.30

Map6.7 50I72 4.57

Map7 G 0.01

Map8 F2 4.30

Map9 F50 15.82

6.3 Extreme event calculation Probable maximum precipitation (PMP) intensities have been calculated for each proposed bridge location (refer to Section 7.6) using the procedures outlined in The Estimation of Probable Maximum Precipitation in Australia: generalised short duration method (Bureau of Meteorology 2003) to determine the 2000-year ARI and PMP temporal rainfall patterns.

These parameters have been input into the XP-RAFTS model to determine the peak flows during the 2000-year ARI and PMP runoff hydrographs. It is assumed the catchment is already wet (initial loss was set to be the same as continuing loss) when modeling the 2000-year ARI and PMP storm events. It is also assumed the full catchment is developed when calculating the PMP event, as any stormwater detention system installed as part of the Alex Avenue Growth Centre Precinct is full and overflowing.

Parameters used in the PMP calculations are detailed in Table 6-3 below. The moisture adjustment factor (MAF) was determined from Figure 3 in The estimation of probable maximum precipitation in Australia: generalised short duration method (Bureau of Meteorology 2003). The elevation adjustment factor (EAF) was adopted as 1.0, as the elevation of the catchment is below 1,500 m Australian Height Datum (AHD). The roughness parameter used in PMP calculations is a measure of how steep the catchment is. Topographic maps were used to determine this parameter.




Table 6-3 Schofields Road catchments PMP calculation parameters

Parameter Value

Moisture adjustment factor 0.69

Elevation adjustment factor 1.0

Percentage defined as ‘rough’ (meaning steep topography)

100%

6.4 Adoption of existing hydrological models Hydrological models have been developed as part of previous investigations for the major catchments within the Schofields Road upgrade study area, as detailed in Section 4.

The models developed for the preliminary study (GHD 2010a) form the basis of the hydrological modelling used for the proposed upgrade. The hydrological models supplied for this study have been reviewed fully and have been updated or had their input parameters amended to the parameters detailed in this Section to develop them to sufficient detail for this assessment.

6.5 Peak flows Flow hydrographs were produced from the XP-RAFTS model for each of the critical duration, design storm events. These hydrographs were used as inputs to the hydraulic model (see Section 7).

Peak flows are summarised in Table 6-4. The critical storm duration is two hours for the 100 years ARI event and 15 minutes for the 2000-year ARI and PMP storms at Eastern Creek Tributary No1 and 2. Critical storm duration at First Ponds Creek is 90 mins for the 100 year ARI event and 30 mins for the 2000-year ARI and PMP events. The 25 min storm is the critical 100-year ARI storm duration at First Ponds Creek Tributary.

Table 6-4 Schofields Road Upgrade – watercourse crossings peak flows

Sub-catchment Location (CH)

Peak flows (m3/s)

100-year ARI 2000-year ARI PMP


4650 23.4 64.09 183.30


4200 3.90 NA* NA*

First Ponds Creek

2800 24.70 97.40 273.40


2500 4.80 NA* NA*

2000 year and PMP events have been analysed for the bridge waterway crossings only

Supporting documentation for the hydrologic analyses is located in Appendix A.




6.6 Comparison of previous studies The 100-year ARI results presented in Section 7.7 have been compared to the results contained in previous studies (detailed in Section 5) where possible. Table 6-5 summarises the comparison of these results.

Table 6-5 Hydrological comparison with previous studies

Catchment Location (CH) 100-year ARI peak flows (m3/s)

Parsons Brinckerhoff

(2011)

GHD (2010) Lyall and Assoc. (2008)


4650 23.4 15.3 24.4*


4200 3.9 3.9 7.2*

First Ponds Creek

2800 24.7 25.0 20.0


2500 4.8 4.9 No information available

*Assumed fully developed catchment

From the table above, it can be seen that the hydrological investigations for this upgrade compare reasonably well with previous investigations in the area.




7. Hydraulic analysis Each watercourse and drainage line crossing the proposed upgrade has been hydraulically modelled using MIKE 11 hydraulic modelling software.

MIKE 11 is a 1D hydraulic model that can be used to simulate steady or unsteady flow in rivers and open channels. The river channel and floodplain is represented in MIKE 11 as a series of cross-sections. The model has the capability to assess the effects of various obstructions, such as bridges, culverts, weirs, and structures in the floodplain.

Two MIKE 11 models have been developed to analyse the watercourse crossings listed in Section 4.3. The design criteria adopted for the hydraulic analysis of these watercourse crossings are detailed in Section 3.

7.1 Adoption of pervious investigation hydraulic models MIKE 11 hydraulic models of Railway Terrace Tributary of Eastern Creek and First Ponds Creek were developed by GHD as part of previous investigations, as detailed in Section 5.2. These models form the basis of the hydraulic modelling used for the project.

The hydraulic models supplied for this study have been reviewed fully and have been updated or had their input parameters amended where deemed necessary to develop them to sufficient detail for this this assessment.

7.2 Cross-sections Cross-section ground levels were derived from ALS survey data collected for the growth centre precinct development control plans. The cross-sections have been checked against the latest ALS survey data and proof checked against the recent ground survey carried out by the Roads and Maritime Services. Cross-sections were spaced about 10–15 m apart and at appropriate distances from hydraulic structures.

7.3 Manning's roughness coefficients Roughness factors, such as vegetation growth, debris, channel bed form and shape, were represented using Manning’s ‘n’ roughness coefficients. Manning’s n-values were adopted based on review of aerial photography, survey data and site visit records.

This concept design has assumed a similar Manning’s value for the main channel and overbank area for both creeks. The adopted Manning’s n-values are listed in Table 7-1.

Table 7-1 Hydraulic model Manning’s ‘n’ values

Reach Main channel and overbanks

Railway Terrace Tributary of Eastern Creek – No.1 0.06

Railway Terrace Tributary of Eastern Creek – No.2 0.06

First Ponds Creek 0.06

First Ponds Creek Tributary 0.06




7.4 Adoption of pervious investigation hydraulic models MIKE 11 hydraulic models of Railway Terrace Tributary of Eastern Creek and First Ponds Creek were developed by GHD as part of previous investigations, as detailed in Section 5.2. These models form the basis of the hydraulic modelling used for the project.

The hydrological models supplied for this study have been reviewed fully and have been updated or had their input parameters amended to the parameters detailed in this Section to develop them to sufficient detail for this assessment.

7.5 Existing conditions Each MIKE 11 hydraulic model has been set up to assess the existing flooding conditions at each watercourse crossing location on Schofields Road.

Each hydraulic model was originally developed as a detailed model for the surrounding growth centre precincts, and therefore extends extensively downstream and upstream of the proposed upgrade crossings. The models have been amended to accurately simulate the existing structures and road levels and therefore determine the existing flood regime in the project area.

7.5.1 Existing hydraulic structures

The following structures have been coded into the hydraulic models – to simulate the existing condition:

Table 7-2 Existing crossing structures

Crossing location Chainage Structure details

Railway Terrace Tributary of Eastern Creek – No.1

4650 5no. X 0.9 m diameter RCP pipe


4200 1no. X 0.9 m diameter RCP pipe

First Ponds Creek 2800 2no. X 1.05 m diameter RCP pipe

First Ponds Creek Tributary 2500 2no. X 0.6 m diameter pipe

The above structure details have been confirmed against the detailed ground survey the Roads and Maritime Services did recently.

7.5.2 Unsteady flow data

Unsteady modelling requires upstream and downstream boundary conditions to be defined for each design storm event. Flow hydrographs developed with XP-RAFTS, as described in Section 6, were defined at the upstream end of each hydraulic model for the 100-year and 2,000-year ARIs and PMP storm events.




7.6 Proposed condition For the proposed condition, the proposed upgrade design levels and the proposed structures have been coded into the hydraulic models.

7.6.1 Riparian corridor assessment

GHD made a riparian assessment as part of the preliminary creek crossing assessment for the project, as discussed in Section 5.2. A representative of the Hawkesbury–Nepean Catchment Authority (HNCA) attended an on-site review of the riparian corridors for this concept design held on 24 August 2011. The HNCA has agreed the riparian corridors originally reported by GHD (2010a, 2010b) can be redefined to the following:

Table 7-3 Riparian corridor requirements

Crossing Location Chainage Preliminary riparian corridor assessment

(GHD 2010a, 2010b) (m)

Minimum structure total

span (m)


4650 72* 40m


4200 NA NA

First Ponds Creek 2800 72* 30m

First Ponds Creek Tributary 2500 NA NA *Includes a 10 m buffer zone

The above riparian corridor will form a minimum structure span for each watercourse crossing location.

7.6.2 Proposed hydraulic structures

The following structures have been coded into the hydraulic models – to simulate the existing condition:

Table 7-4 Proposed crossing structures

Crossing location Chainage Structure details


4650 Approximately 50 m total span bridge


4200 3no. X 3.6 X 0.9 m box culverts*

First Ponds Creek 2800 Approximately 30 m total span bridge

First Ponds Creek Tributary 2500 3no. X 3.6 X 0.9 m box culverts* *Including 50% blockage factor refer Section 3.3




7.7 Modelling results Existing and proposed condition scenarios were run for each design storm event in both MIKE 11 hydraulic models. Detailed outputs including summary tables for each design storm event are located in Appendix B.

7.7.1 100-year ARI event modelling results

Table 7-5 summarises the resulting water levels and afflux for the 100-year ARI event near the proposed upgrade. Figures 4-1 and 4-2, included in Appendix B, show the resulting 100-year ARI floodplain boundary limits for the existing and proposed conditions.

Table 7-5 100-year ARI water level and afflux results

Hydraulic model cross-section location Condition 100-year water

level (mAHD) Afflux (m) Road crest

level (mAHD)

Railway Tributary of Eastern Creek – No. 1

Upstream (chainage 1300.08, about 18 m upstream of Schofields Road)

Existing 23.44 -0.02

Existing: 23.188

Proposed: 25.469

Proposed 23.42



Proposed 23.43

Downstream (chainage 1354.140, about 17 m downstream of Schofields Road)

Existing 21.87 0

Proposed 21.87

Downstream (chainage 1380.480, about 31 m upstream of Schofields Road)

Existing 21.33 0

Proposed 21.33

Railway Tributary of Eastern Creek – No. 2



Existing: 30.37

Proposed: 32.309

Proposed 31.84


Existing 32.51 0

Proposed 32.51 Downstream (chainage 320.39, about 35 m downstream of Schofields Road)

Existing 28.20 0

Proposed 28.20


Existing 27.78 0

Proposed 27.78




Hydraulic model cross-section location Condition 100-year water

level (mAHD) Afflux (m) Road crest

level (mAHD)

First Ponds Creek



Proposed 42.70

Existing: 39.66

Proposed 40.12



Proposed 40.00


Existing 39.52 0

Proposed 39.52


Existing 39.28 0

Proposed 39.28

First Ponds Creek Tributary

Upstream (chainage 650.22, 30 m upstream of Schofields Road )

Existing 42.14 +0.13

Proposed 43.90

Existing: 42.03

Proposed 42.27

Upstream (chainage 621.94, 55m upstream of Schofields Road)


Proposed 42.86

Downstream (Chainage 859.77, 10 m downstream of Schofields Road )


Proposed 40.44

Downstream (chainage 900.19, 50 m downstream of Schofields Road)


Proposed 39.80

Flood extents maps showing the 100-year ARI event flood extent for the existing and proposed case are provided in Appendix B. The proposed upgrade achieves flood immunity during 100-year ARI flood event.

The results above show that zero afflux impacts are achieved at all crossings except First Ponds Creek Tributary. The afflux at First Ponds Creek Tributary is considered minor and the impact dissipates relatively close to the crossing location.

All impacts will be discussed with Blacktown City Council to determine their acceptability. Initial discussions with Blacktown City Council have indicated that minor impacts would be acceptable, and so it is anticipated this impact will be acceptable.

7.7.2 Extreme event modelling results

The 2000-year ARI and probable maximum flood (PMF) events were simulated hydraulically in the proposed case scenario at each bridge location. Peak velocity and peak water level results for a 2000-year ARI event are used during structural design to assess the ultimate




limit state of a bridge. Table 7-6 summarises the resulting water levels at each bridge structure for these events:

Table 7-6 Extreme event water level results

Bridge location Model chainage location

Bridge crest level (mAHD)

2000-year water level (mAHD)

PMF water level (mAHD)


Upstream (chainage 1259.300, about 38 m upstream of Schofields road

25.47 24.06 24.92

First Ponds Creek

Upstream (chainage 1727.15, about 30 m upstream of Schofields road)

42.70 40.90 42.12

7.7.3 Proposed structure results

Table 7-7 summarises the results from the model at the structure locations. Velocities at the structure locations are low and hence the potential for scour at the bridge and culvert locations is deemed low. Scour protection design will be developed for bridge abutments at the detailed design stage. The lower flow through the structures shows that the structure and upstream channel have an attenuating effect on the flood in the creek. This attenuating effect is consistent with the existing condition in the creek due to the negligible afflux shown in Table 7-5.

Table 7-7 Proposed structure results

Structure

100 year ARI 2000-year ARI

Velocity at structure

(m/s)

Flow through

structure (m3/s)

Velocity at structure

(m/s)

Flow through

structure (m3/s)


1.12 17.25 1.80 59.90


1.94* 3.78 NA NA

First Ponds Creek 0.94 18.83 2.31 82.79

First Ponds Creek Tributary 1.79* 3.01 NA NA

*Velocity at outlet of culvert structure




7.7.4 Climate change impacts on proposed bridges

The impacts of future climate change are taken into account when designing bridges. As directed by Blacktown City Council, the effects of an increase in rainfall intensity of 20% at the proposed upgrade structures are summarised in Table 7-8 for peak flood levels.

Table 7-8 Climate change peak flood level results at proposed structures

Structure Condition 100-year ARI Freeboard* (m)

Flow through Structure (m3/s)

Railway Terrace Tributary of Eastern Creek – No.1 (upstream section 1259.300, approximately 38m upstream of Schofields Road)

No climate change 2.04 17.25

Climate change 1.96 21.93

Railway Terrace Tributary of Eastern Creek – No.2 (upstream section 139.72, approximately 40m upstream of Schofields Road)



First Ponds Creek (upstream section 1727.15, approximately 30m upstream of Schofields Road)



First Ponds Creek Tributary (upstream section 621.94, approximately 55m upstream of Schofields Road)

No Climate change 1.03 3.10


*Freeboard measured from crest of carriageway to upstream water level

The effect of climate change results in increased flow through the structures and reduction of freeboard to the proposed upgrade. Climate change does not affect the 100 year ARI design flood immunity of the proposed upgrade.




8. Recommendations/mitigations The results of this study show the proposed upgrade of Schofields Road between Tallawong Road and Veron Road will have negligible impacts on waterway crossing floods.

The potential impacts at each crossing point have been mitigated by the appropriate waterway structure size being specified. Further recommendations and mitigation measures to limit the potential risk of impact from the proposed upgrade are listed below:

A minor flood level afflux occurs at First Ponds Creek Tributary, as detailed in Section 7.7. This will be discussed with Blacktown city Council to determine if it is acceptable. Preliminary discussions with Blacktown City Council indicate this impact will be acceptable because it is confined and not located on developable land.

The hydrological models used to develop the stormwater detention system for the Alex Avenue Growth Centre Precinct will be reviewed when they are received from the Department of Planning. The review will occur during the detailed concept design stage. Its outcomes will feed into the final hydrologic models for the proposed upgrade and ensure the design is consistent with all other surrounding designs for developments within the precinct.

At the detailed design stage – depending on river classification – each watercourse which crosses beneath the proposed upgrade should be assigned an appropriate fish passage design (refer 2003 NSW DPI Fisheries fish friendly roads design guidance in Section 1.5).

At the detailed design stage, scour protection design should be progressed to assess the development of each structure.




9. Statement of limitations This report has been prepared by Parson Brinckerhoff for the Roads and Maritime Services and as such should not be used by a third party without proper reference. The investigation and modelling procedures adopted for this study follow industry standards and considerable care has been applied to the preparation of the results. Study results should not be used for purposes other than those for which they were prepared.



PARSONS BRINCKERHOFF 2113134A-HY-PR-026

Appendix A

Supporting Hydrologic Data

Schofields Road Concept DesignHydrology - IFD parameters

Parsons Brinckerhoff

Schofields Road Upgrade - IFD Parameter ComparisonParameter

Duration ARI1 2 30.7 30.64 30.640

12 2 6.9 6.85 6.85072 2 1.9 1.94 1.9401 50 59 59 59.000

12 50 13 13.33 13.33072 50 4.5 4.57 4.570

skew 0.01 0.01 0.010F2 4.3 4.3 4.300F50 15.85 15.82 15.820Temp zone 1

ARR87 maps

Adopted = BOM

websiteBOM

Website

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10

20

30

40

50

60

70

1 2 3 4 5 6

ARR87 maps

BOM Website

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Schofields Road Upgrade - Australian Rainfall and Runoff - Volume 2 Map extracts2yr 1hr 50yr 1hr

2yr 12hr 50yr 12hr

2yr 72hr

50yr 72hr

#

#

##

# #

* 3First Ponds Creek

Catchment Area: 218.4 Ha

Railway Terrace Tributary No. 1Catchment Area: 100.5 Ha

First Ponds Creek TributaryCatchment Area: 38.1 Ha

Railway Terrace Tributary No. 2Catchment Area: 20.1 Ha

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SCHOFIELDS RD CONCEPT DESIGN

°

0 250 500

Metres

Catchment area

#

Major crossing

#

Minor crossing ALS 0.5m contour (2009) 2m contour (2006)

Note:1. Investigation locations marked are temporary and may change during investigations2. Investigations have been scoped for concept design

Catchment Overview Plan

Eastern Trib XP-RAFTS Hydrologic Model ResultsModel (.xp) Eastern Trib 01Run Date: 15/09/2011ARI (years) 100

ClimateNode T3a T3c T3Type Total Total TotalDuration (min) 120 120 120Peak Q (m3/s) 3.9 15.5 23.4

1 0 0 0 100 1.24 8.398 13.327 201 0.059 0.606 1.0032 0 0 0 101 1.227 8.176 13.062 202 0.058 0.592 0.9813 0 0 0 102 1.197 7.975 12.769 203 0.057 0.579 0.9584 0 0 0 103 1.158 7.832 12.454 204 0.055 0.566 0.9335 0 0 0 104 1.124 7.684 12.129 205 0.054 0.553 0.9126 0.002 0.004 0.003 105 1.095 7.549 11.837 206 0.053 0.541 0.8917 0.018 0.027 0.02 106 1.07 7.417 11.537 207 0.052 0.529 0.8728 0.062 0.069 0.053 107 1.049 7.274 11.293 208 0.051 0.518 0.8539 0.129 0.133 0.147 108 1.029 7.131 11.124 209 0.05 0.507 0.834

10 0.133 0.153 0.254 109 1.009 6.998 10.95 210 0.049 0.496 0.81611 0.127 0.144 0.356 110 0.99 6.894 10.782 211 0.048 0.485 0.79912 0.104 0.134 0.412 111 0.972 6.781 10.603 212 0.047 0.475 0.78213 0.088 0.189 0.456 112 0.954 6.669 10.393 213 0.045 0.46 0.76514 0.083 0.364 0.516 113 0.936 6.538 10.175 214 0.044 0.449 0.74915 0.082 0.492 0.536 114 0.92 6.413 9.979 215 0.043 0.438 0.73416 0.085 0.577 0.54 115 0.903 6.292 9.819 216 0.042 0.429 0.71917 0.1 0.583 0.584 116 0.888 6.162 9.657 217 0.041 0.42 0.70418 0.122 0.597 0.74 117 0.874 6.034 9.501 218 0.04 0.411 0.68419 0.122 0.693 1.026 118 0.862 5.918 9.328 219 0.039 0.403 0.66420 0.124 0.712 1.178 119 0.85 5.807 9.163 220 0.039 0.395 0.64821 0.128 0.719 1.292 120 0.839 5.697 9.003 221 0.037 0.388 0.63322 0.179 0.811 1.336 121 0.824 5.586 8.821 222 0.036 0.38 0.61923 0.26 0.968 1.447 122 0.796 5.477 8.637 223 0.035 0.373 0.60624 0.323 1.061 1.675 123 0.756 5.374 8.459 224 0.034 0.366 0.59425 0.421 1.111 1.806 124 0.719 5.274 8.276 225 0.033 0.36 0.58226 0.497 1.109 1.885 125 0.69 5.173 8.095 226 0.033 0.353 0.57127 0.544 1.167 2.048 126 0.656 5.08 7.926 227 0.032 0.346 0.5628 0.551 1.353 2.197 127 0.624 4.961 7.766 228 0.031 0.339 0.5529 0.609 1.542 2.218 128 0.597 4.822 7.613 229 0.031 0.332 0.5430 0.688 1.678 2.267 129 0.574 4.698 7.465 230 0.03 0.326 0.5331 0.804 1.923 2.42 130 0.553 4.582 7.317 231 0.029 0.319 0.5232 1.105 2.224 2.772 131 0.533 4.471 7.168 232 0.029 0.313 0.50933 1.509 2.502 3.459 132 0.515 4.339 6.968 233 0.028 0.307 0.534 1.838 2.753 4.285 133 0.497 4.187 6.747 234 0.028 0.302 0.4935 2.142 2.994 4.952 134 0.48 4.048 6.546 235 0.027 0.296 0.48136 2.46 3.267 5.559 135 0.463 3.93 6.366 236 0.027 0.291 0.47237 2.709 3.845 6.098 136 0.446 3.798 6.188 237 0.026 0.282 0.46438 2.937 4.773 6.503 137 0.43 3.661 5.99 238 0.026 0.274 0.45639 3.165 5.589 6.879 138 0.414 3.534 5.78 239 0.025 0.268 0.44840 3.411 6.24 7.326 139 0.396 3.414 5.582 240 0.024 0.262 0.4441 3.623 6.694 7.948 140 0.378 3.309 5.414 241 0.024 0.257 0.43242 3.707 7.234 9.07 141 0.365 3.209 5.239 242 0.023 0.252 0.42143 3.719 8.058 10.505 142 0.353 3.113 5.061 243 0.023 0.248 0.41144 3.784 8.777 11.649 143 0.342 3.02 4.895 244 0.023 0.243 0.40345 3.876 9.583 12.682 144 0.331 2.931 4.738 245 0.022 0.239 0.39546 3.924 10.697 13.56 145 0.322 2.836 4.595 246 0.022 0.236 0.38847 3.926 11.536 14.418 146 0.312 2.747 4.46 247 0.021 0.232 0.38148 3.898 11.864 15.547 147 0.303 2.665 4.329 248 0.021 0.228 0.37549 3.873 12.376 16.562 148 0.295 2.589 4.2 249 0.02 0.225 0.36950 3.841 13.038 17.676 149 0.286 2.515 4.071 250 0.02 0.222 0.36351 3.794 13.662 19.009 150 0.278 2.438 3.941 251 0.019 0.218 0.35852 3.744 13.985 19.895 151 0.27 2.368 3.823 252 0.019 0.215 0.35253 3.678 14.131 20.255 152 0.262 2.302 3.715 253 0.018 0.212 0.34654 3.607 14.399 20.826 153 0.254 2.24 3.614 254 0.018 0.209 0.34155 3.526 14.791 21.579 154 0.246 2.181 3.517 255 0.018 0.206 0.33656 3.443 15.032 22.225 155 0.238 2.125 3.418 256 0.017 0.203 0.33157 3.372 15.146 22.508 156 0.231 2.07 3.325 257 0.017 0.2 0.32758 3.307 15.23 22.603 157 0.223 2.016 3.239 258 0.016 0.198 0.32259 3.231 15.34 22.834 158 0.216 1.964 3.156 259 0.016 0.195 0.31760 3.154 15.456 23.177 159 0.208 1.913 3.077 260 0.015 0.192 0.31361 3.076 15.488 23.344 160 0.201 1.863 3 261 0.015 0.189 0.30962 3 15.51 23.372 161 0.194 1.815 2.926 262 0.015 0.187 0.30463 2.929 15.53 23.353 162 0.186 1.769 2.853 263 0.014 0.184 0.364 2.864 15.544 23.35 163 0.179 1.718 2.782 264 0.014 0.182 0.29665 2.804 15.501 23.342 164 0.172 1.667 2.713 265 0.013 0.179 0.29266 2.733 15.423 23.24 165 0.164 1.621 2.645 266 0.013 0.176 0.28867 2.625 15.303 23.133 166 0.157 1.576 2.579 267 0.012 0.174 0.28468 2.516 15.217 22.996 167 0.15 1.534 2.514 268 0.012 0.172 0.2869 2.427 15.106 22.824 168 0.144 1.493 2.446 269 0.012 0.169 0.27670 2.349 14.975 22.594 169 0.134 1.454 2.378 270 0.011 0.167 0.27271 2.28 14.857 22.342 170 0.124 1.416 2.314 271 0.011 0.165 0.26972 2.213 14.681 22.064 171 0.118 1.379 2.253 272 0.011 0.162 0.26573 2.152 14.434 21.834 172 0.113 1.342 2.194 273 0.011 0.16 0.26174 2.095 14.189 21.59 173 0.109 1.306 2.136 274 0.01 0.157 0.25875 2.04 13.98 21.337 174 0.106 1.271 2.079 275 0.01 0.155 0.25476 1.99 13.779 21.083 175 0.103 1.237 2.024 276 0.01 0.153 0.2577 1.963 13.543 20.735 176 0.1 1.203 1.97 277 0.01 0.151 0.24778 1.95 13.256 20.34 177 0.098 1.167 1.918 278 0.01 0.149 0.24379 1.933 13.016 19.989 178 0.095 1.132 1.866 279 0.01 0.147 0.2480 1.914 12.766 19.685 179 0.093 1.099 1.812 280 0.009 0.145 0.23681 1.89 12.493 19.389 180 0.091 1.069 1.759 281 0.009 0.143 0.23382 1.851 12.219 19.051 181 0.089 1.04 1.71 282 0.009 0.141 0.2383 1.807 12.018 18.649 182 0.087 1.012 1.659 283 0.009 0.139 0.22784 1.769 11.806 18.288 183 0.085 0.986 1.611 284 0.009 0.137 0.22485 1.736 11.6 17.926 184 0.083 0.957 1.566 285 0.009 0.135 0.22186 1.701 11.39 17.551 185 0.082 0.927 1.524 286 0.009 0.133 0.21887 1.65 11.163 17.201 186 0.08 0.9 1.485 287 0.008 0.131 0.21688 1.591 10.947 16.924 187 0.078 0.876 1.443 288 0.008 0.13 0.21389 1.538 10.748 16.617 188 0.077 0.853 1.403 289 0.008 0.128 0.2190 1.489 10.551 16.319 189 0.075 0.831 1.363 290 0.008 0.126 0.20791 1.445 10.38 16.011 190 0.074 0.81 1.322 291 0.008 0.124 0.20592 1.403 10.163 15.673 191 0.072 0.783 1.287 292 0.008 0.123 0.20293 1.363 9.896 15.351 192 0.071 0.761 1.254 293 0.008 0.121 0.19994 1.319 9.661 15.063 193 0.069 0.741 1.223 294 0.008 0.119 0.19795 1.28 9.464 14.782 194 0.068 0.722 1.193 295 0.008 0.117 0.19496 1.249 9.256 14.532 195 0.067 0.705 1.164 296 0.008 0.116 0.19297 1.239 9.032 14.221 196 0.065 0.689 1.131 297 0.008 0.114 0.1998 1.244 8.806 13.871 197 0.064 0.673 1.101 298 0.007 0.112 0.18799 1.244 8.59 13.577 198 0.063 0.655 1.074 299 0.007 0.111 0.184

100 1.24 8.398 13.327 199 0.062 0.637 1.049 300 0.007 0.109 0.182101 1.227 8.176 13.062 200 0.06 0.621 1.025

Current

-5

0

5

10

15

20

25

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m3/

s

Time (mins)

100 year ARI event Runoff hydrograph

T3a

T3c

T3

First Ponds Creek XP-RAFTS Hydrologic Model Results RAFTS ExportModel (.xp) First Ponds Ck 01 Start Date is: 23/04/2007Run Date: 18/09/2011 Start Time is: 00:00ARI (years) 100

ClimateNode N3x (first ponds crossing) N3A (First Ponds Trib crossing)Type TotalDuration (min) 90 25Peak Q (m3/s) 24.7 4.8

1 0.0 Storm 100yr 90min 0.0 100yr 25min max [4.779]2 0.0 Storm 100yr 90min 0.0 100yr 25min max [4.779]3 0.0 Storm 100yr 90min 0.1 100yr 25min max [4.779]4 0.0 Storm 100yr 90min 0.3 100yr 25min max [4.779]5 0.0 Storm 100yr 90min 0.529 100yr 25min max [4.779]6 0.0 Storm 100yr 90min 0.851 100yr 25min max [4.779]7 0.0 Storm 100yr 90min 1.296 100yr 25min max [4.779]8 0.1 Storm 100yr 90min 1.803 100yr 25min max [4.779]9 0.3 Storm 100yr 90min 2.3 100yr 25min max [4.779]

10 0.7 Storm 100yr 90min 2.724 100yr 25min max [4.779]11 1.3 Storm 100yr 90min 3.188 100yr 25min max [4.779]12 2.2 Storm 100yr 90min 3.695 100yr 25min max [4.779]13 3.1 Storm 100yr 90min 4.145 100yr 25min max [4.779]14 4.4 Storm 100yr 90min 4.496 100yr 25min max [4.779]15 6.1 Storm 100yr 90min 4.779 100yr 25min max [4.779]16 7.4 Storm 100yr 90min 4.642 100yr 25min max [4.779]17 8.7 Storm 100yr 90min 4.181 100yr 25min max [4.779]18 10.0 Storm 100yr 90min 3.791 100yr 25min max [4.779]19 10.6 Storm 100yr 90min 3.434 100yr 25min max [4.779]20 10.8 Storm 100yr 90min 3.105 100yr 25min max [4.779]21 11.2 Storm 100yr 90min 2.795 100yr 25min max [4.779]22 11.2 Storm 100yr 90min 2.51 100yr 25min max [4.779]23 11.0 Storm 100yr 90min 2.283 100yr 25min max [4.779]24 11.6 Storm 100yr 90min 2.14 100yr 25min max [4.779]25 13.0 Storm 100yr 90min 2.069 100yr 25min max [4.779]26 14.4 Storm 100yr 90min 1.912 100yr 25min max [4.779]27 16.1 Storm 100yr 90min 1.691 100yr 25min max [4.779]28 17.7 Storm 100yr 90min 1.501 100yr 25min max [4.779]29 19.2 Storm 100yr 90min 1.318 100yr 25min max [4.779]30 20.8 Storm 100yr 90min 1.17 100yr 25min max [4.779]31 22.0 Storm 100yr 90min 1.052 100yr 25min max [4.779]32 23.1 Storm 100yr 90min 0.941 100yr 25min max [4.779]33 24.6 Storm 100yr 90min 0.821 100yr 25min max [4.779]34 24.7 Storm 100yr 90min 0.761 100yr 25min max [4.779]35 23.9 Storm 100yr 90min 0.719 100yr 25min max [4.779]36 23.2 Storm 100yr 90min 0.685 100yr 25min max [4.779]37 21.9 Storm 100yr 90min 0.654 100yr 25min max [4.779]38 20.1 Storm 100yr 90min 0.626 100yr 25min max [4.779]39 20.0 Storm 100yr 90min 0.6 100yr 25min max [4.779]40 20.8 Storm 100yr 90min 0.575 100yr 25min max [4.779]41 22.0 Storm 100yr 90min 0.549 100yr 25min max [4.779]42 23.3 Storm 100yr 90min 0.526 100yr 25min max [4.779]43 24.3 Storm 100yr 90min 0.495 100yr 25min max [4.779]44 23.8 Storm 100yr 90min 0.485 100yr 25min max [4.779]45 22.1 Storm 100yr 90min 0.478 100yr 25min max [4.779]46 20.8 Storm 100yr 90min 0.474 100yr 25min max [4.779]47 19.6 Storm 100yr 90min 0.47 100yr 25min max [4.779]48 18.8 Storm 100yr 90min 0.467 100yr 25min max [4.779]49 18.2 Storm 100yr 90min 0.464 100yr 25min max [4.779]50 17.7 Storm 100yr 90min 0.461 100yr 25min max [4.779]51 17.5 Storm 100yr 90min 0.458 100yr 25min max [4.779]52 17.2 Storm 100yr 90min 0.456 100yr 25min max [4.779]53 17.1 Storm 100yr 90min 0.454 100yr 25min max [4.779]54 17.0 Storm 100yr 90min 0.452 100yr 25min max [4.779]55 16.9 Storm 100yr 90min 0.45 100yr 25min max [4.779]56 17.0 Storm 100yr 90min 0.448 100yr 25min max [4.779]57 17.1 Storm 100yr 90min 0.446 100yr 25min max [4.779]58 17.3 Storm 100yr 90min 0.444 100yr 25min max [4.779]59 17.3 Storm 100yr 90min 0.443 100yr 25min max [4.779]60 17.3 Storm 100yr 90min 0.441 100yr 25min max [4.779]61 17.3 Storm 100yr 90min 0.439 100yr 25min max [4.779]62 17.2 Storm 100yr 90min 0.438 100yr 25min max [4.779]63 17.1 Storm 100yr 90min 0.436 100yr 25min max [4.779]64 17.1 Storm 100yr 90min 0.435 100yr 25min max [4.779]65 17.1 Storm 100yr 90min 0.434 100yr 25min max [4.779]66 17.1 Storm 100yr 90min 0.432 100yr 25min max [4.779]67 17.1 Storm 100yr 90min 0.431 100yr 25min max [4.779]68 17.1 Storm 100yr 90min 0.43 100yr 25min max [4.779]69 17.0 Storm 100yr 90min 0.428 100yr 25min max [4.779]70 16.9 Storm 100yr 90min 0.427 100yr 25min max [4.779]71 16.9 Storm 100yr 90min 0.426 100yr 25min max [4.779]72 16.9 Storm 100yr 90min 0.426 100yr 25min max [4.779]73 16.9 Storm 100yr 90min 0.425 100yr 25min max [4.779]74 16.9 Storm 100yr 90min 0.425 100yr 25min max [4.779]75 16.8 Storm 100yr 90min 0.424 100yr 25min max [4.779]76 16.7 Storm 100yr 90min 0.424 100yr 25min max [4.779]77 16.6 Storm 100yr 90min 0.424 100yr 25min max [4.779]

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

30.0

0 100 200 300 400

Axis

Titl

e

Axis Title

100yr ARI First PondsCrossing

100yr ARI First PondsTrib Crossing

Scale 1 : 867.93

L1aL1b

L1

L2

L3

L4

L2a

L4a

L5a

L1dL1c

L3aL4b

L5b

L3x

N1aN1b

N1

N2a

N2

N3

N4

N4a

N5a

N1d

N1c

N3a

N4b

N3x

200 m

mageec

Text Box

FIRST PONDS CREEK RAFTS MODEL LAYOUT

mageec

Callout

Node upstream of First Ponds Creek

mageec

Callout

Node upstream of First Ponds Creek Tributary

Scale 1 : 953.37

L 3g

L Dum3

L 3dL Dum2

L Dum1

L 3h

L 3e

L 3f

L1

L2L4

L7

L9

L10link2

T3 Dum1

T3a

T3c

T3b

Dum2

T3d

T3e

Dum3

T3f

T3g

T3h

T3b1

T3a1

T3c1

d1

200 m

mageec

Text Box

Eastern Creek Tributary - RAFTS Layout

mageec

Callout

Node Upstream of Eastern Creek Tributary No1.

mageec

Callout

Node Upstream of Eastern Creek Tributary No2.

mageec

Callout

Node upstream of Existing crossing of Railway Terrace




Appendix B

Supporting Hydraulic Data

Railway Terrace Tributary of Eastern Creek - 100yr ARI Results

Chainage Existing (mAHD)

Proposed (mAHD) Chainage Existing

(mAHD)Proposed (mAHD) Chainage Existing

(mAHD)Proposed (mAHD)

40 34.91 34.91 20 48.27 48.27 759.5 29.34 29.3460 34.41 34.41 20.64 48.25 48.25 780.07 28.90 28.9080 34.08 34.08 40.14 47.51 47.51 800.36 28.47 28.47

100 33.25 33.25 60.12 46.72 46.72 820.07 28.24 28.24119.67 32.51 32.51 80.09 45.74 45.74 839.94 28.08 28.08139.72 31.85 31.84 99.83 44.92 44.92 859.69 27.95 27.95196.45 30.43 119.94 44.03 44.03 880.14 27.82 27.82223.49 30.42 139.91 43.11 43.11 900.17 27.42 27.42265.57 29.26 160.16 42.44 42.44 920.56 26.98 26.98320.36 28.20 28.20 179.77 41.91 41.91 940.18 26.87 26.87340.09 27.78 27.78 200.03 41.38 41.38 966.12 26.67 26.67360.64 27.44 27.44 220.02 40.91 40.91 997.72 26.32 26.32379.9 26.95 26.95 240.08 40.66 40.66 997.72 26.32 26.32400.46 26.54 26.54 260.06 40.46 40.46 1019.77 26.08 26.08419.19 26.16 26.16 271.47 40.30 40.30 1039.64 25.96 25.96440.55 25.85 25.85 319.98 38.76 38.76 1060.02 25.81 25.81459.64 25.59 25.59 319.98 38.76 38.76 1079.28 25.68 25.68480.24 25.17 25.17 326.53 38.51 38.51 1100.31 25.60 25.60499.84 24.50 24.50 360.29 37.21 37.21 1119.94 25.54 25.54520.15 24.33 24.33 459.94 33.99 33.99 1139.97 25.43 25.43540.02 24.14 24.14 480.02 33.30 33.30 1160.18 25.18 25.18560.15 23.96 23.96 520.35 32.68 32.68 1179.91 23.90 23.89580.44 23.76 23.76 520.35 32.68 32.68 1199.58 23.60 23.59600.13 23.52 23.52 537.54 32.35 32.35 1219.23 23.49 23.47619.99 22.99 22.99 587.29 31.63 31.63 1259.3 23.45 23.43639.68 22.79 22.79 587.29 31.63 31.63 1300.08 23.44 23.42660.59 22.68 22.68 599.61 31.40 31.40 1319.98 23.44 Bridge crossing680.24 22.34 22.34 620.01 30.91 30.91 1342.81 23.42 22.32699.51 22.13 22.13 639.8 30.64 30.64 1354.14 21.87 21.87720.27 21.86 21.86 659.92 30.54 30.54 1380.48 21.33 21.33740.06 21.45 21.45 679.96 30.37 30.37 1399.77 21.10 21.10758.56 21.02 21.03 699.74 30.10 30.10 1420.02 21.07 21.07775.33 20.72 20.72 740.02 29.63 29.63 1439.28 21.05 21.05

1459.74 21.03 21.031479.89 20.75 20.751507.07 20.55 20.551539.48 20.35 20.351551.19 20.29 20.301551.19 20.29 20.30

1562 20.20 20.211580.73 20.17 20.181600.11 20.16 20.161620.55 20.14 20.151639.29 20.13 20.141659.63 20.12 20.131679.68 20.12 20.121722.24 20.09 20.091741.28 20.08 20.081752.8 20.04 20.05

1759.28 19.83 19.83

Tributary 8 - Railway Terrace Tributary of eastern Creek No2 Tributary 8 - Railway Terrace Tributary of eastern Creek No1

Culvert Crossing

302200.0 302400.0 302600.0 302800.0 303000.0 303200.0 303400.0 303600.0 303800.0 304000.0 304200.0 304400.0 304600.0[meter]

6268200.0

6268250.0

6268300.0

6268350.0

6268400.0

6268450.0

6268500.0

6268550.0

6268600.0

6268650.0

6268700.0

6268750.0

6268800.0

6268850.0

6268900.0

6268950.0

6269000.0

6269050.0

6269100.0

6269150.0

6269200.0

6269250.0

[meter] Water Level - 1-1-2008 05:12:45 Existing_01_100yr120mincurrent_01.res11

TRIBUTARY3

TRIBUTARY7

TRIBUTARY8

TRIBUTARY2

TRIBUTARY6

TRIBUTARY6 TRIBUTARY6

TRIBUTARY6

TRIBUTARY6

TRIBUTARY6

TRIBUTARY5

TRIBUTARY5

TRIBUTARY4

First Ponds Creek - 100yr ARI Results

Chainage Existing (mAHD)

Proposed (mAHD) Chainage

Existing (mAHD)

Proposed (mAHD) Chainage Existing

(mAHD)Proposed (mAHD)

53.93 50.37 50.37 1350.02 41.36 41.36 178.15 49.43 49.4396.06 49.94 49.94 1380.19 41.06 41.06 223.9 48.70 48.69

121.67 49.73 49.73 1428.4 40.81 40.81 231.12 48.36 48.35212.21 49.13 49.13 1461.88 40.73 40.73 252.2 47.86 47.86254.11 48.78 48.78 1500 40.59 40.59 270.79 47.27 47.27285.51 48.34 48.34 1504.97 40.58 40.57 289.96 46.96 46.95324.25 48.22 48.22 1538.43 40.44 40.43 311.93 46.73 46.72406.87 47.80 47.80 1538.43 40.44 40.43 348.41 46.55 46.54425.74 47.73 47.73 1555.32 40.34 40.32 362.78 45.70 45.69495.53 47.60 47.60 1630.49 40.22 40.18 382.41 45.50 45.49583.06 46.58 46.58 1684.48 40.17 40.12 401.07 45.43 45.42622.11 46.45 46.45 1727.15 40.10 40.00 420.53 44.67 44.65672.26 46.30 46.30 1776.85 40.06 Bridge 431.83 44.35 44.33748.74 45.78 45.78 1795.2 39.70 Bridge 446.95 44.17 44.16788.34 45.68 45.68 1835.19 39.52 39.52 458.56 44.09 44.08

801.1 45.65 45.65 1889.44 39.28 39.28 473.07 43.97 43.96815.96 45.62 45.62 1939.7 39.11 39.12 491.93 43.92 43.92836.91 45.52 45.52 1983.32 38.93 38.93 504.53 43.90 43.90847.26 45.33 45.33 2050.89 38.46 38.47 523.39 43.83 43.82864.65 44.83 44.83 2067.5 38.36 38.36 529.42 43.76 43.75894.81 44.82 44.82 2067.5 38.36 38.36 535.18 43.54 43.54906.44 44.82 44.82 2110.14 38.24 38.24 546.77 43.51 43.50918.55 44.00 44.00 2186.21 37.96 37.97 572.71 42.92 42.91954.52 43.76 43.76 2236.08 37.70 37.71 598.94 42.91 42.90

1000.33 43.33 43.33 2292.39 37.57 37.57 609.98 42.90 42.891043.65 42.92 42.92 2319.83 37.55 37.56 621.94 42.87 42.861074.94 42.87 42.87 2349.12 37.54 37.55 650.22 42.14 42.271074.94 42.87 42.87 2382.15 37.54 37.54 683.96 41.921084.25 42.84 42.84 2402.34 37.54 37.54 707.08 41.901127.52 42.57 42.57 2421.02 36.90 36.91 716.73 41.871139.86 42.53 42.53 2449.81 36.84 36.84 742.32 41.561161.68 42.51 42.51 2618.78 36.28 36.28 763.84 41.461184.76 42.47 42.47 2666.09 36.07 36.08 796.06 41.401193.97 42.43 42.43 2743.4 35.70 35.70 820.62 40.951204.34 42.15 42.15 2774.64 35.57 35.57 859.77 40.46 40.441221.77 42.10 42.10 2809.57 35.49 35.49 900.19 39.82 39.801239.48 42.03 42.03 2825.23 35.41 35.41 952.38 39.48 39.471279.11 41.81 41.81 2889.75 34.89 34.89 1011 38.96 38.951307.18 41.66 41.66 2948.96 34.21 34.21 1088.68 38.25 38.36

First ponds Creek Tributary - 100 yr ARIFirst Ponds Creek - 100yr ARI

Culvert Location

304500.0 305000.0 305500.0[meter]

Water Level - 1-1-2008 00:00:00 Existing_01_100yr90mincurrent_01.res11

TRIB3ALEX

TRIB4ALEX

TRIB2ALEX

TRIB2ALEX

TRIB5ALEX

FIRSTPONDCRK

FIRSTPONDCRK

FIRSTPONDCRK

6267900.0

6268000.0

6268100.0

6268200.0

6268300.0

6268400.0

6268500.0

6268600.0

6268700.0

6268800.0

6268900.0

6269000.0

6269100.0

6269200.0

6269300.0

6269400.0

6269500.0

6269600.0

6269700.0

6269800.0

[meter]

Railway Terrace overtops in100 year event (existing and

proposed case)

Existing overtopping of roadculverts causing excessive flood

extents in the existing case

Approx. 50m span bridge

SCHOFIELDS ROAD

RAILWAY TERRACE

BRIDGE STREET

ADVANCE STREET

JUNCTION ROAD

TAIN PLACE

HUNT STREET

LANE GROVE

EOS PLACE

BRIDGE STREET

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0 100 200

Metres

Drainage Proposed ARI 100yr flood Existing ARI 100yr flood


Map 1 – Railway Terrace Tributary of Eastern Creek – 100yr ARI Flood outline

Slight downstream impact due to removal of road culvert

Decrease in impact upstreamdue to removal of road culvert

30m bridge option

Creek realignment

Proposed culvert crossing

FIRST PONDS C

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SCHOFIELDS ROAD

ALEX A

VENUE

HAM

BLED

ON R

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BOUNDARY ROAD

TALLAWON

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0 100 200

Metres

Proposed culvert Drainage Proposed ARI 100yr flood Existing ARI 100yr flood


Map 2 – First Ponds Creek – 100yr ARI Flood outline

mageec

Callout

Proposed outlet works

mageec

Callout

Additional Culvert required under Access road

mageec

Callout

Connect to existing downstream channel

mageec

Callout

Culvert skewed to avoid major water direction change training works




Appendix C

Minutes of Meetings




From: CAMPBELL Jim A [mailto:[email protected]] Sent: Wednesday, 31 August 2011 12:43 PM To: Gazzini, Elaine; Magee, Colm; [email protected]; SHUTTLEWORTH Hannah; Dibb, Kieran Cc: SURENDRAN Suresh Mur; BESTWICK Susan Subject: FW: FW: Schofields Rd Stage 2 creek crossings All Response from Office of Water below. In summary the outcome is: 1. no issues with realignment of First Ponds Creek tributary 2. 30m bridge over First Ponds creek is sufficient for both flood and riparian corridor requirements. 3. No issues with Junction Road tributary. 4. 50m bridge crossing of Railway Tce tributary will meet flood requirements (40m) plus additional riparian corridor of 10m on eastern side of creek. 5. No issues identified regarding option for gravity drainage of underpass feeding adjacent to the railway culvert for the Railway Terrace tributary. Hannah and I met with Fisheries today. No issues or requirements identified, and as a consequence of the meeting, creeks will be de-classified from their current listing as fish habitat. It was noted that what is proposed will result in an improvement compared to the current situation. Regards Jim

From: Greg Brady [mailto:[email protected]] Sent: Wednesday, 31 August 2011 9:27 AM To: CAMPBELL Jim A Subject: Re: FW: Schofields Rd Stage 2 creek crossings

Hi Jim, the notes are a reasonable representation of our site meeting and discussion. The RTC bridge width I note is still a minimum of 40m, the actual riparian corridor is over 60m and then plus a buffer. After reviewing what was done by the GCC for the riparian areas and the significance of the vegetation outside of the proposed road footprint, the width of the split bridge should be around the 50m. Also to clarify matters, I am now fully with Office of Water and not OHN (the email address is a hangover of this recent change) and confusing to many unfortunately. So as you are likely to be using the meeting outcomes in your REF, it is best to have the right agency quoted........................... Regards Greg Greg Brady Natural Resource Officer Office of Water Level 4, 2-6 Station Street (PO Box 323) PENRITH NSW 2751 Phone direct 4729 8134




Phone general 4729 8138 Fax 4729 8141 >>> CAMPBELL Jim A <[email protected]> 8/30/2011 3:03 pm >>> This time with the attachment!

From: CAMPBELL Jim A Sent: Tuesday, 30 August 2011 3:00 PM To: Greg Brady Cc: SHUTTLEWORTH Hannah Subject: Schofields Rd Stage 2 creek crossings

Greg Following on from our meeting last week I have attached the strategic concept design to assist with your review. In particular we are seeking confirmation of the riparian corridor for the Railway Terrace bridge crossing - see comments in email below. Please let me know timing of your review so we can progress the concept design. All the best Jim Campbell 0411438698

From: CAMPBELL Jim A Sent: Wednesday, 24 August 2011 4:51 PM To: Greg Brady; Magee, Colm; [email protected]; SHUTTLEWORTH Hannah Cc: Elaine Gazzini PB ([email protected]); SURENDRAN Suresh Mur ([email protected]) Subject: Schofields Rd Stage 2 -Office of Hawkesbury Nepean - meeting outcomes

All I have put together my recollection of the outcomes of the meeting today as a draft. Please let me know if any changes/additions needed. 1) Overview An overview was provided of the precinct rezoning plans (now rezoned) including the Alex Avenue Stormwater Management Strategy with Online Basins. The project was summarised as upgrading the existing 20 m rural road corridor to a 43m urban road to be developed as a four lane road with wide verges and medians and with future capacity for widening to six lanes within the median. When developed to four lanes the median would be 15m wide and reduced to 9m if developed to six lanes. All bridges will be twin bridges with separation consistent with median widths. It was noted that further discussions would be held with the Department of Fisheries next week. It was noted that any detention basins for the road would be primarily focussed on construction management. Any water quality treatment is proposed to be limited to gross pollutant traps.




2) First Ponds Tributary This creek is identified to be realigned under the precinct plans. The proposal would result in some encroachment to the existing pond south of the alignment. A triple box culvert is proposed and is likely to be diagonally skewed under the road and would then follow the proposed northern verge westwards until rejoining the existing creek. There is the potential for additional skewing at the join. Further investigation to confirm that the proposed alignment is within the REF footprint. Colm to advise potential alignment - one week? Care will be needed to align the culvert away from unsuitable material. Ultimately Hambledon Rd would need to be extended northwards. This may involve further realignment outside of the Hambledon Road footprint but this would be the responsibility of future private developers and Council in providing consent. Office of Hawkesbury Nepean (OHN) concurred with this approach. 3) Junction St Tributary A triple box culvert is proposed. No proposal for creek realignment. 4) Bridges Two bridges are proposed at First Ponds Creek (FPC) and also at the Railway Tce crossing (RTC). An overview was provided confirming that this section of Schofields Road would be designed as 'secondary' flood evacuation route for the 100 year ARI. It is proposed to undertake as sensitivity analysis for the PMF in relation to bridge heights. Bridge structures would be designed to allow for overtopping for the 2000 year ARI. It was agreed that the proposed bridge separation would provide for sufficient light and it was noted that the bridges would at a height sufficient for maintenance access but not pedestrian access. It was agreed that appropriate creek treatment would be provided management strategies identified in the REF. The REF would be displayed for public and stakeholder comment. It was agreed that there is no requirement for riparian buffer zones for this project. It was advised that the flood design would require a 30m bridge at FPC. This was agreed to be sufficient to also cater for riparian corridor requirements. At the RTC it was identified that flood requirements dictated a minimum 40m bridge. It was noted that the fenced 'fauna and flora' area would be almost entirely under the proposed alignment. RTA agreed to provide OHN with drawings of proposed alignment. OHN advised it would review and confirm riparian corridor requirements for this crossing. 5) Underpass drainage RTA identified that it is likely for the future rail underpass to be permanently pumped out. There is potential for gravity drainage which is to be investigated. - If feasible the drainage line would follow a path between the railway corridor and the proposed realigned Railway Tce and could potentially include in-line detention basin(s). These are expected to be within the REF footprint but connection to the tributary feeding from the Railway Tce crossing would be beyond the REF footprint. Colm to advise feasibility / potential alignment - one week? Regards Jim A Campbell Project Development Manager Sydney Infrastructure Development Ph: 02 8849 2377 Fax: 02 8849 2817 Email: [email protected]




Before printing, please consider the environment. IMPORTANT NOTICE: This e-mail and any attachment to it are intended only to be read or used by the named addressee. It is confidential and may contain legally privileged information. No confidentiality or privilege is waived or lost by any mistaken transmission to you. The RTA is not responsible for any unauthorised alterations to this e-mail or attachment to it. Views expressed in this message are those of the individual sender, and are not necessarily the views of the RTA. If you receive this e-mail in error, please immediately delete it from your system and notify the sender. You must not disclose, copy or use any part of this e-mail if you are not the intended recipient. Before printing, please consider the environment. IMPORTANT NOTICE: This e-mail and any attachment to it are intended only to be read or used by the named addressee. It is confidential and may contain legally privileged information. No confidentiality or privilege is waived or lost by any mistaken transmission to you. The RTA is not responsible for any unauthorised alterations to this e-mail or attachment to it. Views expressed in this message are those of the individual sender, and are not necessarily the views of the RTA. If you receive this e-mail in error, please immediately delete it from your system and notify the sender. You must not disclose, copy or use any part of this e-mail if you are not the intended recipient.

appendix h hydrology and hydraulic assessment...3.2 afflux 6 3.3 waterway structure blockage 6 3.4...

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