stormwater management report · this stormwater management report has been prepared by acor...

STORMWATER MANAGEMENT

REPORT

Homebush Apartments

Cnr Powell St and Parramatta Rd, Homebush, NSW

February 2015

Prepared by: ACOR Consultants Pty Limited

Level 1, 24 Falcon Street

CROWS NEST NSW 2065 Tel: 02 9438 5098 Fax: 02 9438 5398

Homebush Apartments - STORMWATER MANAGEMENT REPORT Page ii

TABLE OF CONTENTS

EXECUTIVE SUMMARY ................................................................................................................ iv

1 INTRODUCTION ................................................................................................................... 1

1.1 Purpose of Report ................................................................................................................. 1

1.2 Project Description ................................................................................................................ 1

1.3 Guidelines and Standards ..................................................................................................... 1

2 EXISTING CONDITIONS ...................................................................................................... 2

2.1 Existing Site Description ........................................................................................................ 2

2.2 Existing Stormwater Drainage ............................................................................................... 2

3 PROPOSED DEVELOPMENT .............................................................................................. 3

3.1 Proposed Site Development .................................................................................................. 3

3.2 Proposed Stormwater Drainage Layout ................................................................................ 3

3.3 Design of Proposed Drainage System .................................................................................. 3

4 CONCLUSION ....................................................................................................................... 5

APPENDIX A - DRAWINGS ............................................................................................................ 6

APPENDIX B – MUSIC MODEL ...................................................................................................... 7

Homebush Apartments - STORMWATER MANAGEMENT REPORT Page iii

ISSUE AND REVISION RECORD

Issue Date Purpose Prepared By Checked By Approved By

A 14/02/2014 Review JS GK GK

B 26/02/2014 DA Submission JS RE RE

C 27/2/2015 DA Submission JS GK GK

D 02/03/2015 DA Submission JS GK GK

This document is issued for the party which

commissioned it and for specific purposes connected with

the above-captioned project only. It should not be relied

upon by any other party or used for any other purpose.

We accept no responsibility for the consequences of this

document being relied upon by any other party, or being

used for any other purpose, or containing any error or

omission which is due to an error or omission in data

supplied to us by other parties

This document contains confidential information and

proprietary intellectual property. It should not be shown to

other parties without consent from us and from the party

which commissioned it.

Homebush Apartments - STORMWATER MANAGEMENT REPORT Page iv

EXECUTIVE SUMMARY

This Stormwater Management Report has been prepared by ACOR Consultants for the proposed residential development located at Cnr Powell St and Parramatta Rd, Homebush NSW.

This report documents the methodology involved in determining the design of the proposed stormwater and water quality treatment train.

The report finds that the installation of rainwater tanks, a bio-retention system and a detention system in the Homebush Apartment complex achieve the required water quality performance requirements as required by the Strathfield Consolidated Development Control Plan (2005) and the Strathfield Council Stormwater Management Code (1994).

Homebush Apartments - STORMWATER MANAGEMENT REPORT Page 1

1 INTRODUCTION

1.1 Purpose of Report

This Stormwater Management Report has been prepared by ACOR Consultants for the proposed residential development located at Cnr Powell St and Parramatta Rd, Homebush NSW.

This report documents the methodology involved in determining the design of the proposed stormwater drainage system for the proposed developments, including the stormwater quantity and quality management.

1.2 Project Description

ACOR Consultants has been engaged by Al Maha PTY LTD to prepare a Stormwater Management Plan and Water Quality Modelling report for the proposed development located at Cnr Powell St and Parramatta Rd, Homebush, NSW. The proposed Homebush Apartments will be a residential apartment block with an underground car park and ground floor retail outlets. The development will consist of the following:

- Demolition of existing buildings - Removal of trees - Excavation and construction of a residential apartment and car park

complex

1.3 Guidelines and Standards

The stormwater system is to be designed to the local authority and water authority requirements:

- Strathfield Council Stormwater Management Code - Strathfield Council Consolidated Development Control Plan

Water Sensitive Urban Design (WSUD) is to be designed to the following documents:

- ‘Part N of Strathfield Consolidated Development Control Plan 2005 – Water Sensitive Urban Design (WSUD)’ published by Strathfield Council

- ‘Strathfield Council WSUD Reference Guideline’ published by Strathfield Council


2 EXISTING CONDITIONS

2.1 Existing Site Description

The proposed site is bound to the North and East by bushland/undeveloped land and a motorway, to the South by Parramatta Rd and to the West by Powell St.

The property is currently occupied by a single story building which will be demolished during the development.

2.2 Existing Stormwater Drainage

The site has an existing system of stormwater drainage of which will be either incorporated or replaced by the new stormwater system. Please refer to Appendix A for details.


3 PROPOSED DEVELOPMENT

3.1 Proposed Site Development

The proposed development will include the construction of a residential complex as well as a number of retail outlets at the ground floor level. The stormwater system will be designed to convey the 100 year ARI storm event for the property.

The proposed layout will be as shown in Appendix A.

3.2 Proposed Stormwater Drainage Layout

Stormwater from the proposed Homebush Apartments site will be directed through a pit and pipe system into rainwater tanks, through a detention basin and into a bio-retention system before being directed to an existing stormwater connection point along the North side of the property. This point becomes the point of discharge for the site. The stormwater system is designed to convey up to a 1 in 100 year stormwater event. Please refer to Appendix A drawings showing the stormwater catchment boundary.

3.3 Design of Proposed Drainage System

3.3.1 On-Site Detention

The site will include an on-site detention basin of volume 95.4m3 located at the North East border

of the property. The detention basin will have a surface area of 120m2. The proposed layout will

be as shown in Appendix A.

The property will also include 2 rainwater tanks sized at 23.4m3 and 37.4m

3 which will be

positioned at the appropriate positions relating to their rooftop catchment.

3.3.2 Maintenance Plan

Provision for litter bins, signage, education and regular sweeping of the accessible drainage catchments will help to reduce litter loads generated by the site.

The recommended maintenance regime for the tertiary treatment processes shall be instigated by the property manager to ensure suitable pollutant removal efficiencies of the systems.

3.3.3 Stormwater Quality Management

The proposed drainage system has been designed in accordance with the Strathfield Council requirements. The requirements are found in the Strathfield Council publication ‘Part N of Strathfield Consolidated Development Control Plan 2005 – Water Sensitive Urban Design (WSUD)’.

The following water quality targets are to be achieved as set by the council guidelines:

- 90% reduction in the post development mean annual load of total gross pollutant (greater than 5 mm).

- 85% reduction in the post development mean annual load of Total Suspended Solids (TSS).

- 60% reduction in the post development mean annual load of Total Phosphorus (TP).


- 45% reduction in the post development mean annual load of Total Nitrogen (TN).

3.3.4 Stormwater Quality Treatment Train

It is proposed to install rainwater tanks, a bio-retention system and a detention basin to treat the stormwater within the post-development design. The roof runoff will be deposited in the rainwater tank; any excess will be directed into the bio-retention and detention systems with the urban surface runoff before being discharged to stormwater connection point indicated above.

3.3.5 MUSIC Modelling

The MUSIC software package has been used to model the water quality for the post-developed site to calculate the pollutant loads from the development and the effectiveness of the treatment train. The perviousness of catchment areas is based on the design as detailed in Appendix A. Roofs, roads and pathways were all designated as 100% impervious.

The model was run to calculate the reduction in the mean annual loads for the proposed development. A summary of the results are shown below in Table 3.1. Full MUSIC results are attached in Appendix B.

Table 3.1 – MUSIC Output – Post Developed Mean Annual Loads for the Homebush Apartments

Parameter In Out % Removal Required

% Removal Achieved

Total Suspended Solids (kg/yr) 1320 152 85% 88.4%

Total Nitrogen (kg/yr) 18.7 9.9 45% 47.1%

Total Phosphorous (kg/yr) 2.64 0.993 60% 62.4%

Gross Pollutants (kg/yr) 166 0.00 90% 100%

As can be seen in table 3.1 above, the Suspended Solids, Nitrogen, Phosphorus and Gross Pollutants are all reduced by the treatment train proposed for this development. These results meet the requirements as set by the Strathfield Council publication ‘Part N of Strathfield Consolidated Development Control Plan 2005 – Water Sensitive Urban Design (WSUD)’.


4 CONCLUSION

The proposed Homebush Apartment Complex incorporates rainwater tanks in conjunction with bio-retention and detention systems to improve stormwater quality before it discharges as the designated stormwater discharge point.

The above measures achieve the requirements as set out by ‘Part N of Strathfield Consolidated Development Control Plan 2005 – Water Sensitive Urban Design (WSUD)’ in conjunction with the ‘Stormwater Management Code’ both published by Strathfield Council.


APPENDIX A - DRAWINGS

ACOR Consultants Drawings:

C1.01 Ground Floor Stormwater Detention Plan

C2.01 – OSD/Bio-retention Details

+RL6.660

208m2

RL+7.670

+RL8.750

+RL7.800

RL+7.670

+RL8.700

181 m2

+RL6.660

322 m2

243m2

+RL8.700

+RL8.750

69m2

+RL8.250

+RL6.670

+RL8.700

+RL6.660

+RL7.660

+RL7.228

RL+9.400

+RL6.660

RL+8.700

+RL6.965

89m2

+RL7.450

+RL8.700

+RL7.660

+RL6.660

+RL8.250

35m2

104+RL8.250

+RL8.250

LIFT5A +RL

8.700

+RL8.750

+RL6.660

RL+8.700

101

BU

IL

DIN

G A

56m2

10273m2

103

80m2

206m2

LIFT5B

STAIR3B

STAIR4B

LIFT4A

LIFT4B

LIFT6A

LIFT6B

STAIR 3C

STAIR 3A

STAIR 4C

STAIR 4A

UPFROM B1

FHBV FSBV

PA

RR

AM

AT

TA

RO

AD

EXISTING SYDNEY WATER

SEWER MAIN TO BE MADE

REDUNDANT

EXISTING STORMWATER

TO BE DIVERTED ANDMADE REDUNDANT.

EXISTING SEWER MAIN

OSD BASIN120m

2 APPROX.

BIO-RETENTION40m

2 APPROX.

TOP OF WALL

7.60

STORMWATER DRAINAGE NOTES:

OSD:RESIDENTIAL SITE AREA: 6,257m

2

OSD STORAGE REQUIRED - 15m3 PER 1,000m

2 : TOTAL 94m3

PSD REQUIRED - 23L/s PER 1,000m2 OF SITE AREA: TOTAL 143.91L/s

RAINWATER TANKS: REFER TO BASIX REQUIREMENTS (TOTAL 20kL MINIMUM)

WATER QUALITY TREATMENT: MUSIC MODELLING

REFER TO THE STORMWATER DRAINAGE REPORT

PROPOSED SUBSOIL PIPE(TYPICAL)

EXISTING STORMWATER PIT

CL 6.61IL 4.84

GD

IL 6.00

IL 5.76

IL 5.744

IL 8.20 SWP

SWP

SWP

SWP

GDGD

GD

SW Ø225

IL 6.10

RWT

SWP

SWP

SWP

SWP

SWP

SWP

SWP

SWP

SW Ø300

SW Ø225

GD

SWP

IL 7.60

SWP

SWP

SWP

SW Ø150

SW Ø225

SWPSW

P

SWP

IL 6.00

SWP

SWP

IL 5.90

SWP

SW Ø300

GD

SWP

SWP

0102

03

04

ABOVE GROUND ROOF WATER STORAGE TANK DETAILN.T.S.

01020304

Ø2380

2500

P:\SY13\SY130538\Drawings\CIV\Drawings\130538_C1.01.dwg

NOT FOR CONSTRUCTION

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IssueDescription

DateDrawn

Approved

COPYRIGHT of this design and plan is the

property of ACOR Consultants Pty Ltd,

ACN 079 306 246 ATF The ACO

R Unit Trust

ABN 26 522 454 721, all rights reserved. It

must not be used, m

odified, reproduced orcopied w

holly or in part without w

rittenperm

ission from ACO

R Consultants Pty Ltd.

C

No

rth

This drawing has been assigned an electronic code that signifies the drawing has been checked andapproved by:

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61 2 9438 5098

Drawing Title

Al Maha Pty Ltd

CNR POWELL ST & PARRAMATTA RD

HOMEBUSH APARTMENTS

EAST SYDNEY NSW 2010

2 LIVERPOOL LANE

HOMEBUSH NSW 2140

PHONE : 8354 1300Project No.Designed

DrawnDate

ScaleQ.A. Check

Dwg. No.

Date

Issue

A1

SY130538

FAX : 8354 1311

CIVIL SERVICESGROUND FLOOR STORMW

ATER DETENTION PLAN

SMcG

RG

FEB 141:200

C1.01B

RE25.02.14

P1FOR CLIENTS COMMENTS

21.02.14SMcG

REA

DA SUBMISSION26.02.14

SMcGRE

BDA SUBMISSION

26.02.15BL

REC


BLRE

ON SITE DETENTION AND BIO-RETENTION BASIN SECTION1:50

AAC1.01

PROPOSED RETAINING WALL

(BY OTHERS)

1.7m WIDE BERM

3

EXISTING STORMWATER

PIPE IL 4.84. 450mm DIA.APPROX

BIO-RETENTION FILTER MATERIALAS SPECIFIED ON DETAIL

RL 6.30

CL 7.45

1BW

L 6.60

TWL 7.45

ON SITE DENTION ZONE- VOLUME 95m

3EXTENDED DETENTIONDEPTH

NSL

TOW 7.60

RL 7.60

EXISTING STORMWATER PIT

TO BE RECONSTRUCTED

CL 6.60

185mm DIA.

CONSTRUCT 0.54mm HIGHx 82mm W

IDE WEIR

OPENING IN PIT AT RL6.91

340mm2YR WL

850mm100YR WL

560.00mm10YR WL

31

GEOTEXTILE LAYER BIDUM 34

100

13

MINIMUM 200mm PONDING DEPTH IN BASIN

FILTER MEDIUM 5mm PARTICLE DIAMETERCOMPRISING FINE GRAVEL

100mm DIAMETER SLOTTED uPVC SUBSOILDRAINAGE PIPE W

RAPPED IN FILTER SOCK.PIPE TO RUN THE LENGTH OF BIOTRENCHAND CONNECT AND DRAIN INTO PIT

TOP SOIL 150mm

13

100mm DOUBLE WASHED

COARSE SAND

WATER QUALITY TREATMENT BASIN

AND BIORETENTION TRENCHN.T.S.

500100

1500

100

NOM. 100Ø HDPE (CORRUGATED ANDPERFORATED), SUBSOIL DRAINAGE LINEW

RAPPED IN GEOTEXTILE FILTER FABRICAT MIN. 0.5%

FALL.SUBSOIL PIPE LINE TO DISCHARGE TOSTORMW

ATER PIT, HEADWALL OR OUTLET

WITH SCOUR PROTECTION.

300 MINBELOW SUBGRADE

100600

20mm SINGLE SIZE AGGREGATEAS SPECIFIED

GEOTEXTILE FABRICBIDIM A24 OR APPROVEDEQUIVALENT

TYPICAL SUBSOIL DRAINAGE DETAIL (SSD)SCALE 1:20

LANDSCAPELANDSCAPE

SCALE 1:20

SURFACE INLET/JUNCTION PIT PIT TYPE "A"PLAN

SCALE 1:20

2-FLOW

PROVIDE STEP IRONS IF PIT DEEPERTHAN 900 (REFER DETAILS).

PROVIDE 3.0m LENGTH OF 100ØSUBSOIL W

RAPPED IN GEOFABRICSOCK AT UPSTREAM END OF PIT.

SECTION2-

MASS CONCRETE BENCHING.

MORTAR BED

N12 AT 200 BOTHWAYS

CENTRAL

30 FALL UNO

PIT IN CONCRETE PAVEMENT REFER DETAIL 'B' PITIN FLEXIBLE PAVEMENT REFER DETAIL 'C' PIT INLANDSCAPE AREAS REFER DETAIL 'D'

COVER (WITH SUITABLE LIFTING HOLES) OR GRATE

& FRAME AS SPECIFIED.

225

150MIN

150 "X" 150

70

400 LAP TYP

Y/2

300 TYP 300

150 DEPTH AS REQUIRED (D)

150"Y"

150

MIN

900900

D 1200

900600

D 1200

600*600

D 900

450*450

MINIMUM INTERNALPIT DIMENSIONS"Y"

"X" "D"

D 600

NOTE: PITS DENOTED * SHALL BEUSED ONLY W

HERE SPECIFIED INDRAINAGE SCHEDULE OR ON PLAN.

P:\SY13\SY130538\Drawings\CIV\Drawings\130538_C2.01.dwg

NOT FOR CONSTRUCTION

Mar 02, 2015 - 9:18am

Clie

nt

Arch

ite

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Pro

je

ct

IssueDescription

DateDrawn

Approved

COPYRIGHT of this design and plan is the

property of ACOR Consultants Pty Ltd,

ACN 079 306 246 ATF The ACO

R Unit Trust

ABN 26 522 454 721, all rights reserved. It

must not be used, m

odified, reproduced orcopied w

holly or in part without w

rittenperm

ission from ACO

R Consultants Pty Ltd.

C

No

rth

This drawing has been assigned an electronic code that signifies the drawing has been checked andapproved by:

-10

1cm at full size10cm

EN

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EE

RS

MA

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61 2 9438 5098

Drawing Title

Al Maha Pty Ltd

CNR POWELL ST & PARRAMATTA RD

HOMEBUSH APARTMENTS

EAST SYDNEY NSW 2010

2 LIVERPOOL LANE

HOMEBUSH NSW 2140

PHONE : 8354 1300Project No.Designed

DrawnDate

ScaleQ.A. Check

Dwg. No.

Date

Issue

A1

SY130538

FAX : 8354 1311

CIVIL SERVICESOSD/BIORETENTION DETAILS

EMEM

FEB 14AS SHOW

N

C2.01B

RE25.02.14

P1FOR CLIENTS COMMENTS

21.02.14SMcG

REA


SMcGRE

BDA SUBMISSION

26.02.15BL

REC


BLRE


APPENDIX B – MUSIC MODEL

Figure 1 - MUSIC Model Layout and Results for the Homebush Apartment Complex

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