Original source · versioned page text
2 Emerald SWMP 2213_Rev1
Attached to the e-mail MCU22/0062 - Response to Council Information Request.
PROPOSED COMMERCIAL PREMISES
INTEGRATED WATER MANAGEMENT PLAN
VERSION 1
FOR
QUEENSLAND PROPERTY DEVELOPMENTS PTY LTD
HOUSE 2
LOT 47 on C5602 EMERALD ST,
COOROY
JULY 2022
10
9
T T T T T T
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2
RP170689
0
11
UP
LIFT
2
23 PWD
RP43490
B=0.0447Ha
46
C5602 0
11
1 1
11 RP44101
RAMP DN 1 IN 20
B=0.0521Ha
111 2
RP44101 A=0.0702Ha
5.5m²
112
112
Callaghan & Toth
Civil, Environmental &
Hydraulic Engineers
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Callaghan & Toth
DOCUMENT HISTORY
Document Reference: No: 2213 SWQMP_Rev1.doc
Project Manager: Mark Hafner
Author: Lex Toth
Client: Queensland Property Developments Pty Ltd
Contact Person: Mark Hafner Wiltshire Stevens Architects
DISTRIBUTION LIST
POSITION ON
NAME ORGANISATION MANAGEMENT REVISION REVISION REVISION REVISION
TEAM 0 1 2 3
Mark Hafner Wiltshire Stevens Client 1 1
Architects
Lex Toth Callaghan & Toth Author 1 1
Nadine Gorton Noosa Council Assessment Officer 1 1
REVISION LIST
REVISION DATE DISTRIBUTED ISSUED BY CHECKED BY
0 7 June 2022 Lex Toth Monte Plasman
1 7 July 2022 Lex Toth Monte Plasman
The information contained in this report is confidential and proprietary to Callaghan & Toth Civil,
Environmental & Hydraulic Engineers. It may only be used by the person to whom it is provided,
for the stated purpose for which it is provided, and must not be imparted to any third person
without the prior written approval of Callaghan & Toth. Callaghan & Toth reserves all legal rights
and remedies in relation to infringement of its rights in respect of its confidential information.
©
Callaghan & Toth
2022
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Callaghan & Toth
CONTENTS
1. INTRODUCTION................................................................................................. 4
1.1 Response to Conditions of Approval ......................................................................... 4
2. DESCRIPTION.................................................................................................... 4
3. FLOODING ......................................................................................................... 4
4. STORMWATER DESIGN AND ASSESSMENT ................................................. 8
4.1 Proposed On-Site Stormwater Treatment Process ..................................................... 8
4.1.1 Rainfall Data ........................................................................................................ 8
4.2 HYDROLOGY .......................................................................................................... 8
CONCLUSIONS ....................................................................................................... 09
APPENIDX 1: Summary of Detention Calculation Results ................................. 10
LIST OF REFERENCES
1. Engineers Australia (2006) Australian Runoff Quality. Australian Runoff Quality
Guidelines.
2. Healthy Waterways (2006) Water Sensitive Urban Design Technical Design
Guidelines for Southeast Queensland
3. Water by Design, Deemed to Comply Solutions – Stormwater Quality Management
(Southeast Queensland), May 2010
4. QUDM (Queensland Urban Drainage Manual 2016)
5. AS/NZS 3500.3.2003 Stormwater Drainage
6.
LIST OF FIGURES
Figure 1.1 Proposed Carpark Layout & Catchment 6
Figure 1.2 Proposed Stormwater Management Plan 7
LIST OF TABLES
Table 1.1 Response to Information request 5
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Callaghan & Toth
1. INTRODUCTION
The site subject to this report is at No.2 Emerald Street Cooroy. One existing house and
shed on the lot has been removed to be replaced by a commercial building and carpark.
The stormwater management assessment undertaken in this project considers the increase
in impervious area of the lot due to the proposed commercial building and carpark. Then it
determines which measures can be incorporated into the design to attenuate the resultant
increase in runoff back to predevelopment levels.
The existing dwelling catchment drains to Emerald Street.
The existing dwelling site currently drains to Emerald Street as shown on Figure 1.1. the
proposed new drainage system will replicate the existing catchment. An existing roof water
outlet from an adjacent property will be incorporated into the interlot drainage system.
1.1 Response to Conditions of Approval
TABLE 1.1: Response to Information Request
NUMBER CONDITION RESPONSE
5.1 The design levels for the various structures Details shown on Figure
1.2
5.2 The discharge rates at the kerb and channel outlets. Details shown on Figure
Please note that the maximum discharge at any one 1.2
location is 25l/sec
5.3 Clarification on the pipe type within the road reserve. Details shown on Figure
Please note that the pipe type must be suitable for use in 1.2
the road reserve
5.4 Demonstrate that the proposed stormwater system will be Details shown on Figure
able to convey the stormwater generated by the new 1.2
development on a 20% AEP event
5.5 RPEQ certification that the design is in accordance with Figure 1.1 & 1.2
the Noosa Plan and QUDM SWQMP plans attached
are signed by RPEQ
and are certified to be in
accordance with The
Noosa Plan and QUDM
2. DESCRIPTION
The site is on a 1,012 m2 parcel of land which has frontage to both Emarald Street and
Wimmers Lane. There is an existing underground drainage system with a kerb and a
channel in Emerald Street. A property in Wimmers Lane discharges roof water onto the site.
3. FLOODING
The existing house drains toward Emerald Street. The downpipes discharge into an existing
kerb and channel in Emerald Street.
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Callaghan & Toth The runoff from the Wimmers Lane and adjacent building is collected by kerb and channel and an existing underground stormwater drainage system. The whole lot is above flood levels. Hafner 2213 SWMP_Rev1.docx July 2022 5 2213
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9
SWP
IL: 107
.47
300 Dia
Callaghan & Toth
LL: 108.55 m 300 Dia
RCP EMERALD
IL: 107.70
STREET Civil, Environmental &
IL: 107
.67
SW Pits Hydraulic Engineers
S
S S S S S S S S S S S S S
T T T T T T T T T T T T
W W W H W W W W W W W W W
WM
2
RP170689
0
11
UP
LIFT
2
23 PWD
RP43490
B=0.0447Ha
0
11
111 RP44101
1
RAMP DN 1 IN 20
B=0.0521Ha
111 2
RP44101 A=0.0702Ha
5.5m²
112
S S S S S S S S S S
S S S
WIMMERS 112 LANE
Page 7
SWP 300 Dia
LL: 108.55 m 300 Dia
RCP
IL: 107
.67
IL: 107.70
SW Pits
EMERALD STREET Callaghan & Toth
S
Civil, Environmental &
Hydraulic Engineers
Sewer M/H
LL: 109.83
S S S S S S S S S S S S S S S S S S IL: 107.053 S S S S IL: 106.82
S
Sewer M/H IL: 107.80
LL: 108.64
T T T T T T T T T T T T
W W W W W W W W W W W W
RL109.800
+ + + + + + + + +
Single Storey
SW
Timber Building
RL110.000
Single Storey
Block Building
0
11
SW
UP
SW
T T
+
LIFT
+
S S
+
W W + + + +
SW SW SW SW
+
+
+
+
+
+ RL110.600
SW
23 PWD
+
+
+
+
+ +
0
SW
11
+
+
+
+
SW
LINE OF UPPER FLOOR BUILDING DOTTED OVER
+
+
+ +
SW
111
SW
SW
SW
+ + +
SW SW SW SW SW
RAMP DN 1 IN 20
Single Storey
Block & Iron Building
111
5.5m²
112
Sewer M/H
WIMMERS LANE LL: 112.51
S S S S S S S S S S S S IL: 110.14
S
112
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Callaghan & Toth 4. STORMWATER DESIGN AND ASSESSMENT 4.1 Proposed On-Site Stormwater Treatment Process The developed site was divided into Sub-Catchments as shown on Figure 1.1 and the detention system is listed below: 1. An Underground Rainwater Detention Tank will be required to collect water from all the roof area and carpark of the commercial building. A total of one (1) tank 8.73m long with a capacity of 7.4m3 will be provided for the new commercial building. The tank discharge to an overflow pipe discharging to the underground drainage system. The total tank capacity is to be 7,400 litres and is adequate for the approximate attenuation of runoff back to predevelopment concentrations for AEP1%, 10%, 50%. 2. The underground drainage system is designed to convey a 20% AEP event. An overland flow path has been provided to convey large events. 4.1.1 Rainfall Data The meteorological data used for the BOM IFD table for Cooroy was used for the runoff calculations 4.2 HYDROLOGY The site has been modelled using HydroCAD 10 to determine the detention capabilities of the rainwater tanks. The underground rainwater detention tanks adopted have been sized so that runoff concentrations are reduced back to predevelopment levels as shown in our calculations in Appendix 1. As the existing runoff and catchment extents to Emerald Street is not to be affected by this development, there will be no change to the capacity of drainage to Emerald Street. Hafner 2213 SWMP_Rev1.docx July 2022 8 2213
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Callaghan & Toth CONCLUSIONS The Underground Rainwater Detention Tank is able to attenuate the runoff concentrations back to predevelopment levels and so the development will not have an impact on the hydrology of the existing system. The internal drainage system has been designed to carry the 20% AEP and existing adjacent property’s roof water runoff. Hafner 2213 SWMP_Rev1.docx July 2022 9 2213
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Callaghan & Toth
APPENIDX 1: Summary of Detention Calculation Results
2 EMERALD STREET COOROY
Pre-Development Case
968m² Catchment
tc = 6 min., C=0.65
Cf50%=0.85, Cf10%=1.00, Cf1%=1.20
Q1% flow = 0.0622 m³/s
Q10% flow = 0.0355 m³/s
Q50% flow = 0.0227 m³/s
Post-Development Case (No Detention)
968m² Catchment
tc = 6 min., Commercial C=0.9
Cf50%=0.85, Cf10%=1.00, Cf1%=1.20
Q1% flow = 0.0796 m³/s
Q10% flow = 0.0492 m³/s
Q50% flow = 0.0314 m³/s
Post-Development Case (with Detention)
968m² Catchment
tc = 6 min., Commercial C=0.9
Cf50%=0.85, Cf10%=1.00, Cf1%=1.20
Q1% flow = 0.0622 m³/s
Q10% flow = 0.0290 m³/s
Q50% flow = 0.0190 m³/s
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