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Spiire Australia Pty Ltd ABN 55 050 029 635 T 61 3 5448 2500 spiire.com.au

16 Bridge St PO Box 1064 Bendigo Victoria 3550 Australia

G:\30\300477\R01 002 Drainage Strategy Progress Report .docx Page 1

Report

To Roy Cai

From Spiire Date 13 September 2014

Project Name Beryl Street Oakleigh South Reference 300477R01

Subject Drainage Strategy and Preliminary Modelling/Functional Design Progress Report

1 Meeting with Council

Spiire has met with James Patterson and Adrian Willoughby from the City of Monash on the 10th June

2014 to discuss drainage matters relating to the proposed development site.

Key outcomes were as follows:

- The development is to retard site developed flows back to pre-development levels.

- The development does not need to consider the impacts of increased volume downstream of the

site. Note: This is not usually the case however Council as the responsible authority can overrule

the general requirements of Clause 56 of the Victorian Planning Provisions.

- The development will not require WSUD, however a GPT may be required. Note: This is not

usually the case however Council as the responsible authority can overrule the general

requirements of Clause 56 of the Victorian Planning Provisions.

- The site either needs to be able to convey existing overland flows through the site and or divert

them around the site demonstrating no detrimental impact to surrounding properties.

- 150mm freeboard to garage level and 300mm freeboard to building floor level will be required for

the development from overland flow / storage for the 1 in 100 year ARI levels.

- An auxiliary flow path will be required for events larger than 1 in 100 year ARI.

Key discussions:

- The discussion of diverting external flow around the site was tabled, (it will be very difficult to

convey flows through the site to free board requirements and also provide onsite detention the

separation of internal and external flows will be critical) Council were in favor as long as it could be

demonstrated that no detrimental impact was caused to surrounding properties. It was noted that

this would require alteration to existing traffic calming devices in Beryl Avenue.

- There was discussion about using the open space for a percentage of the storage.

- Council were in favor of the overland flow path to Golf Road.

- There was discussion about two retarding areas to split the site. See attached sketch 1.

- There was discussion about the limitations of the existing drainage depth 1.1m to invert.




2 Preliminary 2 dimensional (2d) Modelling

Spiire have undertaken a preliminary 2d modelling of the site along with additional survey to include

the full road reserve.

Catchment plans have been calculated from Landvic data and XPstorm 2D model conducted based

on the existing terrain. The rational formula method has been used for 100 year (1% probability) inflow

hydrographs.

2.1 Existing Conditions Preliminary Modelling

The existing model indicates flows from catchment A (South East) are directed north up Bakers Rd

and across the existing site due to limited survey. These flows may implicate the existing northern

neighboring properties.

The minimum freeboard to the residents is at Lot 107 with a predicted freeboard of 430mm and Lot 27

with 500 freeboard which is greater than the min 300mm.

2.2 Proposed Development Preliminary Modelling

The proposed development area was eliminated from the 2D model. Results show the 100 year flows

will be redirected away from crossing the proposed development site and the northern properties. An

overland flow will occur to the north of Bakers Rd. Our model though has not allowed this discharge to

occur. The model directs flows around to Golf Rd and Delia St. Our model does not consider flow

levels further North to Golf Rd. The flow levels to Golf Rd are increased in height. The approximate

maximum increase in water depth is 130mm in front of Lot 111. Refer attached diagrams.

Minimum freeboard to the residents is at Lot 107 with a maintained 460mm and Lot 27 with 500mm

freeboard. A manual check of the cross section at Golf Rd confirms the flow heights are consistent

with a manning’s formula check.

The flows are considered acceptable with freeboards to the existing resident’s floor level being above

300mm.

The design levels of the estate will need to consider the flow elevation determined from the 2d model.

In particular floor heights to Bakers Rd. Further investigation of the Bakers Rd flow path will be




undertaken during detailed design and conversations held with council about a provision for overland

flows to be maintained North of Bakers Rd.

3 Preliminary On Site Detention Computations and Drainage Layout

Preliminary on site detention calculations for the development site have been conducted. The outcome

of these calculations are:

- Approximately 107 m3 of storage will be required on site to retard developed flows back to

predevelopment levels. This figure needs to be confirmed by obtaining an aerial of the site when it

was occupied by the school to determine the pre development fraction impervious. The allowable

discharge of 593 L/s has currently been estimated base on the previous zoning this needs to be

agreed with council.

- The detention storage is proposed to be stored using a Humes Stormtrap system. Humes has

been contacted and Spiire has supplied information to confirm the detention volume in the

proposed layout and determine costs. The system proposed will utilize a 1.175m internal height

units and have a heavy duty loading suitable for construction traffic.

- Detailed modelling and design needs to occur to ensure the detention storage size and incoming

pipes can convey the Q100 flows to Golf Rd.

The attached functional plans indicate a preliminary drainage layout.

4 Functional Layout.

A functional layout has been developed for services include water and sewerage. This layout is

preliminary only and required further computations and services design. The proposed development

will require a high level of services co-ordination. The existing sewer depths in the proximity of the

development look to have adequate depth the command the development.

5 Detailed Design.

Spiire believe the preliminary design work indicates the drainage strategy can be implemented and

functional design and further detailed design work can proceed to finalise the development.

© Spiire

The information contained in this document is intended solely for the use of the client identified in the ‘To’ field for the purpose

for which it has been prepared and no representation is made or is to be made or is to be implied as being made to any third

party. Other than for the exclusive use of our client, no part of this report may be reproduced, stored in a retrieval system or

transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior written permission

of Spiire Australia Pty Ltd.

A FUNCTIONAL LAYOUT PLANS

SIM DEVELOPMENT PTY LTD

BERYL AVE SUBDIVISIONFUNCTIONAL LAYOUT

file name 300477F1-FS.dwg layout name F1-1

file location G:\30\300477\ACAD

plotted by Joshua Hall plot date 11/9/2014 3:40 PM

ABN 55 050 029 635 Innovation in

Infrastructure

FUNCTIONAL LAYOUT

FACE SHEET

FUNCTIONAL ARRANGEMENT


CITY OF MONASHMELWAY -

01

PRELIMINARY

-

R.PLOURDE

-

J.HALL

G.ROZEN

469 La Trobe Street PO Box 16084 Melbourne Victoria 8007 Australia T 61 3 9993 7888


Infrastructure

BERYL AVE SUBDIVISION

FUNCTIONAL LAYOUT

CATCHMENT PLAN



01

PRELIMINARY

-

J.HALL

-

J.KOEHLER

-


IL57.49

IL57.21

IL56.02

IL56.00

IL57.47IL57.27IL57.14

IL5

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IL56.61

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IL54.8

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A FUNCTIONAL DRAWING FOR APPROVAL J.Hall 11/09/14

file name 300477F2-FP.dwg layout name F2-1




Infrastructure


FUNCTIONAL LAYOUT

EXISTING CONDITIONS PLAN



02

PRELIMINARY

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R.PLOURDE

-

J.HALL

G.ROZEN


IL57.49

IL57.21

IL56.02

IL56.00

IL57.47IL57.27IL57.14

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FUNCTIONAL LAYOUT

SHEET LAYOUT



03

PRELIMINARY

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R.PLOURDE

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J.HALL

G.ROZEN


IL54.9

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plotted by Joshua Hall plot date 12/9/2014 9:27 AM


Infrastructure


FUNCTIONAL LAYOUT

FUNCTIONAL LAYOUT



04

PRELIMINARY

-

R.PLOURDE

-

J.HALL

G.ROZEN


IL57.21

IL56.02

IL57.27IL57.14

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Infrastructure


FUNCTIONAL LAYOUT

FUNCTIONAL LAYOUT



05

PRELIMINARY

-

R.PLOURDE

-

J.HALL

G.ROZEN


IL57.49

IL57.21

IL57.47IL57.27IL57.14

IL57.1

5

IL57.16

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Infrastructure


FUNCTIONAL LAYOUT

FUNCTIONAL LAYOUT



06

PRELIMINARY

-

R.PLOURDE

-

J.HALL

G.ROZEN

469 La Trobe Street PO Box 16084 Melbourne Victoria 8007 Australia T 61 3 9993 7888 A FUNCTIONAL DRAWING FOR APPROVAL J.Hall 11/09/14

6.0M

2.15M600 600200

1.35M

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1000

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file name 300477F3-XS.dwg layout name F3-1


plotted by Joshua Hall plot date 12/9/2014 9:29 AM


Infrastructure


FUNCTIONAL LAYOUT



07

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R.PLOURDE

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J.HALL

G.ROZEN


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