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124-002 Technical Memorandum Revision B
CIVIL ENGINEERING PROJECT MANAGEMENT
SEDIMENT AND EROSION CONTROL
TECHNICAL MEMORANDUM
Stormwater Management
36 ENTERPRISE STREET, SUNSHINE BEACH
DATE: 20.12.23 REF: 124-002-01
ATT: Mr Michael Klobas EMAIL: [email protected]
REV: B
Bax Engineering has been commissioned by Mr and Mrs Michael and Judy Klobas to review the existing
stormwater drainage system and provide a stormwater management plan for the proposed residential
development as shown on the Zauss House plans WD1.0 to WD3.1 (dated 01.08.23); located at 36 Enterprise
Street, Sunshine Beach Queensland (Lot 5 on RP81810).
The review considers the use of tank storage and flow diversions to the street frontage to mitigate flows to
the existing inter allotment drainage at the rear of the property. It is expected that this would ease the burden
on the existing stormwater network and reduce the risk of nuisance flooding.
The report is based on the photographs and site investigations taken by Bax Engineering. It is of a professional
opinion and supplied without prejudice.
Page 1 of 6
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Page 2
SITE ANALYSIS
LOCALITY
The site is described as Lot 5 on RP81810 at 36 Enterprise Street, Sunshine Beach in Queensland. The subject
site is shown in Figure 1.
Figure 1 - Locality Plan
Source: Qld Globe
SITE CHARACTERISTICS
The site naturally falls towards the east to the rear of the property. There is no registered easement nor any
formal inter-allotment drainage for this property (or others along Enterprise Street) that slope away from a
lawful point of discharge in Enterprise Street.
The site has significant fall towards the rear boundary of greater than 25%. An existing field inlet is located at
the lowest point and drains via a 90mm stormwater pipe between 3 and 5 Dolphin Bay Drive. The outlet
configuration of this pipe is unknown. The nearest stormwater network appears to be a 300mm diameter
system located in Dolphin Bay Drive. (Refer Appendix A).
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2261 david low way, peregian beach, qld 4573 acn: 626 671 092 [email protected]
Page 3
The existing house on the property will be demolished as part of the new construction. The existing house has
a footprint of 336m2. This is a coverage of 48% of the overall 690m2 site area. Currently this roof area is
connected to rainwater storage tanks with their outlets discharging overland towards the eastern boundary.
There have been some crude attempts at fashioning drains along the rear boundary to help channel these
flows away from the existing buildings and towards the drainage outlet.
The proposed new dwelling will have a proposed area of 344m2 which is 50% of the site area. It is expected as
part of the building design, a majority of this roof area will be able to be discharged to Enterprise Street.
Nevertheless, there will still be a portion of stormwater that will need to be managed in order to remove any
nuisance flows towards the east.
PROPOSED STORMWATER MANAGEMENT
It is proposed that the downstream drainage system remains untouched. It is unknown if any other properties
are connected to it and the area over the pipe alignment appears to be well established.
It is instead proposed to remove all but necessary flows from entering this existing system. By installing tanks
at the rear of the property would allow capture of peak flows as well as provide retention storage for water
re-use. Once the tanks are filled, the roof catchments would then be diverted to the Enterprise Street frontage.
Based on the existing dwelling roof area of 336m2 the flows from the existing roof to the eastern boundary
would be 24L/s approximately based on a Q20 5-minute storm.
The tanks are expected to be incorporated into the retaining along the eastern boundary. This would ensure
that they would not be obtrusive.
It is expected that the tank could be either cast in-situ concrete as part of the building construction or placed
as a proprietary product. The tank is shown as part of Figure 2 and would allow connection from the proposed
roof area.
Areas of the proposed dwelling that are too low to be connected to the tanks such as outside impervious areas
would divert to the eastern boundary. Calculations provided by the Hydraulic Engineers indicate that these
flows would be at a maximum of 22L/s. This is less than the calculated volume currently reaching the eastern
boundary and ensure a non-worsening condition. These flows would be discharged onto the property site and
dispersed through gravel beds for scour protection.
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2261 david low way, peregian beach, qld 4573 acn: 626 671 092 [email protected]
Page 4
Figure 2 – Proposed stormwater tank location
Source: BRW Hydraulics
PROPOSED HYDRAULIC DESIGN
CHARGED DRAINAGE LINES
The maximum potential head on the charged line is 2.600m and measured between the Ground floor roof
and the discharge point at the kerb. With the charged roof water line running full the head loss and flow
rates in the pipe discharging to the kerb are as follows:
• 23m of 150mm PVC, equivalent length including fittings = 40.5m. Flow rate = 19.3L/s. Therefore the
Headloss in 150mm PVC pipe (6.5m/1000m) = 0.263m
• 6.5m of 150mm PVC, equivalent length including fittings = 20.0m. Flow rate = 14.4L/s. Therefore the
Headloss in 150mm PVC pipe (4.0m/1000m) = 0.08m
• 26m of 100mm PVC, equivalent length including fittings = 30.5m. Flow rate = 6.2L/s. Therefore the
Headloss in 100mm PVC pipe (4.3m/1000m) = 0.134m
Page 4 of 6
2261 david low way, peregian beach, qld 4573 acn: 626 671 092 [email protected]
Page 5
The total minimum required head above the discharge point is 0.477m. With 2.600m of potential head
available this is easily achieved and demonstrates that the charged line would be functional.
FIRST FLUSH DEVICE
The first flush diverter will operate typical to the below Figure 3. When the 147 litres 300mm PVC pipe is full,
the ball float blocks the first flush and diverts water to the discharge point at the driveway. The first flush
volume and the water held in the pipework below the discharge point will be approximately 853 litres and
will drain to the rear via a 20mm drain pipe. The flow rate of this 20mm pipe will be approximately 0.5L/s
Figure 3 – Proposed First Flush Device
BUTTERFLY VALVE TANK DIVERSION
All roof water will drain directly to the rainwater storage tank with an electronic butterfly valve to
automatically switch-over and discharge to the kerb and channel on Enterprise Street when the rainwater
tank is full. This will ensure that the proposed stormwater design will not alter the site’s stormwater
discharge characteristics in a manner that may substantially damage or cause nuisance to a third-party
property.
Page 5 of 6
2261 david low way, peregian beach, qld 4573 acn: 626 671 092 [email protected]
Page 6
CONCLUSION
The report has briefly reviewed the proposed stormwater management for the future dwelling at 36 Enterprise
Street in Sunshine Beach.
In summary:
• Discharge from the site is towards the eastern boundary and away from the street frontage. This
appears to be a similar issue for adjacent properties with grades away from their frontage in Enterprise
Street.
• The proposed system will ensure that no flows are worsened towards the eastern property by
diverting flows to the Enterprise Street frontage using a charged pipe system.
• It is proposed to mitigate peak flows as much as possible to allow the existing system to cope. It is
proposed to do this by diverting all roof water flows to an underground tank for reuse. Once the tank
is full the system will divert the flows to the Enterprise Street frontage.
• With flows being diverted to the Enterprise Street frontage, nuisance flows to the eastern boundary
will be reduced.
• The tank could be placed in a location that would be non-obtrusive and be incorporated as part of the
retaining of the property.
Yours Faithfully,
GLENN AINSWORTH
MIEAust CPEng NER RPEQ CPESC
BAX ENGINEERING PTY. LTD.
Ph: 0407 021 300
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2261 david low way, peregian beach, qld 4573 acn: 626 671 092 [email protected]
Page 7
APPENDIX A Noosa Council Stormwater Mapping
Page 8
Noosa Shire Council does not warrant the accuracy of information in this publication and 20/11/2021 any person using or relying upon such information does so on the basis that Noosa Shire Council shall bear no responsibility or liability whatsoever for any errors, faults, 1:1129 defects or omissions in the information.
Page 9
APPENDIX B Hydraulic Layout
Page 10
LEGEND
A
SCALE: SURVEYED: CLIENT: NORTH POINT TITLE:
KLOBAS ROADWORKS AND DRAINAGE
DATUM: AHD Skyline Surveyors LAYOUT PLAN - LOWER FLOOR
C 09.11.23 HYDRAULIC DESIGN REVISED QT GWA
B 21.07.23 SW AMENDED
A 28.02.22 ISSUE FOR APPROVAL
QT
QT
GWA
GWA
PROJECT NO:
124-002
LOCAL AUTHORITY APPROVAL NO:
DATE
CHECKED
DRAWN
09.11.23
GWA
QT
APPROVED:
GLENN AINSWORTH
CPESC No: 7678
RPEQ No: 19204
Engineering
DA ID LOW WAY PEREGIAN EACH LD
PTY LTD
PROJECT:
36 ENTERPRISE ST SUNSHINE BEACH
No. DATE REVISIONS BY CKD --- DESIGNED QT FOR AND ON BEHALF OF BAX ENGINEERING PTY. LTD. IN O A ENGINEERING COM AU PLAN No 124-002-301 REVISION C A1
Page 11
DRAINAGE PLAN No.
STORMWATER
SUBSOIL
CAST IN
A BA ISSUE HB 25.10.23
DD1 DESIGN DEVELOPMENT ISSUE LN 03.07.23
Level 3, 39 Sherwood Road,
Toowong, QLD 4066
PH: (07) 3876 0088
[email protected]
www.brwhydraulics.com.au
QBCC LIC. No. 15067628
PROPOSED STORMWATER
DESIGN FOR RESIDENTIAL
DEVELOPMENT
36 ENTERPRISE STREET,
SUNSHINE BEACH, QLD, 4567
COVER SHEET, LEGEND,
NOTES AND LOCATION PLAN
B. NIKOLAJEVS
LN (QBCC LICENCE N° 15058052) JUNE 2023
As Shown
@ A1
20190 H01 A
Page 12
DRAINAGE PLAN No.
SPECIFIC NOTES
1 SPS TRUFLO 100mm 90° RWO WITH
ALL PURPOSE PLANTER BOX
ADAPTER. MODEL No. TIA100/90PB.
2 SPS TRUFLO 100mm RWO WITH ALL
PURPOSE PLANTER BOX ADAPTER.
MODEL No. TIA100PB.
3 PLANTER DRAINAGE CELL
4 SPS PARAPET DRAIN. MODEL No. LANDSCAPED ROCK/
PD100CS. GRAVEL BED.
FAL
L FROG FLAP
:100
@1
100
L
O/F FAL
:100
100
65 @1
100
100∅ OVERFLOW
LL
:100 FA
100 @ 1
100 @ 1
SWD
1 00
SWD 100 SWD
:100 FA
IN COLUMN 65
65
BED 3 DP
6.2L/S DOWNPIPE TANK FILL
100
LL
100
COS UP
THRESHOLD DRAIN. BUTTERFLY VALVE NOTE:
PIPEWORK CAST IN COLUMN. (REFER TO ARCH) SWD
100
(STRUCTURE TO CONFIRM) 65 THE ELECTRICAL BUTTERFLY VALVE SHALL BE
100∅ AGG. DRAIN CONTROLLED BY FLOAT LEVEL SWITCH.
COMPLETE WITH FILTER 100 BED 4 ENS BUTTERFLY VALVE TO BE OPEN UNTIL WATER
SOCK. FALL 1:200 MIN. LEVEL REACHES 50mm BELOW OVERFLOW LEVEL.
SWD
BOXED IN PROVIDE MANUAL OVERRIDE AT CONTROL PANEL.
100 REFER TO ELECTRICAL ENGINEERS DRAWINGS.
POOL
100 PVC
ABOVE
CLASS
LAUNDRY FAMILY
WET AREA UP
12
THRESHOLD DRAIN. TERRACE
DN
(REFER TO ARCH) RL 61600 RAINWATER STORAGE TANK.
FALL
STUDY FALL WET DOWNPIPE (SIZE TO BE CONFIRMED BY
RL 61600
SYSTEM.
ARCHITECT)
LIFT SUMP PIT 300mm
ENTERPRISE ST
x 300mm x 300mm. FOYER SWD
(REFER DETAIL) 65 FROG FLAP
LIFT
DP
100∅ AGG. DRAIN CONCRETE UP 4.1L/S
STAIRS 100
COMPLETE WITH FILTER ENS
100 @ 1
SOCK. FALL 1:200 MIN. COS LANDSCAPED ROCK/
LIFT COS DP GRAVEL BED.
150 PVC
4.1L/S
PLANT 100
:1
00 FALL
ROOM METER THRESHOLD DRAIN.
ROOM GYM (REFER TO ARCH)
CLASS
BED 2 100∅ OVERFLOW
SWD
BOXED IN
12
SWD 100 DP
100 4.9L/S
150
100 150
50
150
100 @ 1:100 FALL
100
100
0
150 50
15
COS
100 20 SWIP 300x300mm L/D
100
UP 0
15 GALVANISED GRATE.
150 @ 1:100 FALL 150 @ 1:100 FALL 150
150 PVC CLASS 12
REFER TO GROUND FLOOR SWD
PLAN FOR CONTINUATION. 65 2,000mm LONG x ∅300mm IN-GROUND
FIRST FLUSH DEVICE WITH REMOVABLE
WET DOWNPIPE
100mm TO 20mm REDUCER INSIDE SWIP
SYSTEM. BUTTERFLY VALVE FOR MAINTENANCE.
CONTROL PANEL IN
WEATHERPROOF BOX. PROCESS SYSTEMS LUGGED DUCTILE IRON B REVISED BA ISSUE LN 30.10.23
ELECTRICAL BUTTERFLY VALVE 150mm 240V
A BA ISSUE HB 25.10.23
LOWER FLOOR PLAN / DRAINAGE AC ELECTRICAL EPDM (ALLOW ALL COSTS).
INSTALLED IN ACCESS CHAMBER WITH 50mm DD1 DESIGN DEVELOPMENT ISSUE LN 03.07.23
SCALE 1:100 DRAIN.
Level 3, 39 Sherwood Road,
Toowong, QLD 4066
PH: (07) 3876 0088
[email protected]
www.brwhydraulics.com.au
QBCC LIC. No. 15067628
150mm INLET TO TANK
200mm
300mm
150∅ OVERFLOW
150 CLASS 12
PROPOSED STORMWATER
DESIGN FOR RESIDENTIAL
DEVELOPMENT
RAINWATER
STORAGE TANK
36 ENTERPRISE STREET,
SUNSHINE BEACH, QLD, 4567
PROCESS SYSTEMS LUGGED DUCTILE
IRON ELECTRICAL BUTTERFLY VALVE
150mm 240V AC ELECTRICAL EPDM
LOWER FLOOR PLAN
(ALLOW ALL COSTS). INSTALLED IN DRAINAGE
ACCESS CHAMBER WITH 50mm DRAIN.
50mm DRAIN
FLOAT LEVEL SWITCH TO
AUTOMATICALLY OPERATE B. NIKOLAJEVS
BUTTERFLY VALVE. LN (QBCC LICENCE N° 15058052) JUNE 2023
As Shown
TANK VALVE DETAIL @ A1
NOT TO SCALE
20190 H02 B
Page 13
DRAINAGE PLAN No.
SPECIFIC NOTES
1 SPS TRUFLO 100mm 90° RWO WITH
ALL PURPOSE PLANTER BOX
ADAPTER. MODEL No. TIA100/90PB.
2 SPS TRUFLO 100mm RWO WITH ALL
PURPOSE PLANTER BOX ADAPTER.
MODEL No. TIA100PB.
3 PLANTER DRAINAGE CELL
4 SPS PARAPET DRAIN. MODEL No.
PD100CS.
SWD DP
65 L FALL
6.2L/S
SWD FAL 100
SWD 100 O/F FAL
L
IN COLUMN
65 65
65 SWD
3
DN PDO 65
PIPEWORK CAST IN COLUMN. PIPEWORK CAST IN SLAB.
(STRUCTURE TO CONFIRM) 2 (STRUCTURE TO CONFIRM)
S THRESHOLD DRAIN.
THRESHOLD DRAIN. FALL
(REFER TO ARCH)
(REFER TO ARCH)
SWD
65
FALL 100 LIVING
POOL OUTDOOR LIVING
RL 64982
100
65
65
DINING
RL 65000
TERRACE
SHR
THRESHOLD DRAIN.
THRESHOLD DRAIN. (REFER TO ARCH) THRESHOLD DRAIN.
(REFER TO ARCH) ENTRY (REFER TO ARCH)
FALL
DN KITCHEN
10
LIFT BUTLERS SWD
0
@
PANTRY
1:1
65
00
ENTERPRISE ST
FA
200mm WIDE x 100mm DEEP
LL
CONCRETE UP
TRENCH DRAIN WITH H/D STAIRS SWD
BOXED IN
GRATE WITH 150mm OUTLET. 100
DP B REVISED BA ISSUE LN 30.10.23
GARAGE 4.1L/S
150 @ 1:100 FALL
100 100
A BA ISSUE HB 25.10.23
150 @ 1:100 FALL PDR DP
RL 65000 STORAGE FALL 4.1L/S DD1 DESIGN DEVELOPMENT ISSUE LN 03.07.23
BED 1 100
DRIVEWAY WIR ENSUITE THRESHOLD DRAIN.
100 (REFER TO ARCH)
Level 3, 39 Sherwood Road,
Toowong, QLD 4066
PH: (07) 3876 0088
BINS FALL DN SWD SWD DP
4.9L/S [email protected]
BOXED IN 65 100
100 www.brwhydraulics.com.au
2x 150mm x 75mm HIGH H/D RHS 150 PVC CLASS 12 QBCC LIC. No. 15067628
DISCHARGE TO EXISTING KERB
FALL 1:200. (ALLOW ALL COSTS) WET DOWNPIPE REFER TO LOWER FLOOR
450mm x 450mm SWIP WITH SYSTEM. PLAN FOR CONTINUATION.
L/D GALVANISED GRATE AND LANDSCAPE BUILT UP TO
FRAME. (ALLOW ALL COSTS) ALLOW GRAVITY DISCHARGE
OF STORMWATER TO KERB.
(ALLOW ALL COSTS)
GROUND FLOOR PLAN / DRAINAGE
SCALE 1:100
PROPOSED STORMWATER
DESIGN FOR RESIDENTIAL
DEVELOPMENT
36 ENTERPRISE STREET,
SUNSHINE BEACH, QLD, 4567
GROUND FLOOR PLAN
DRAINAGE
B. NIKOLAJEVS
LN (QBCC LICENCE N° 15058052) JUNE 2023
As Shown
@ A1
20190 H03 B
Page 14
DRAINAGE PLAN No.
SPECIFIC NOTES
1 SPS TRUFLO 100mm 90° RWO WITH
ALL PURPOSE PLANTER BOX
ADAPTER. MODEL No. TIA100/90PB.
2 SPS TRUFLO 100mm RWO WITH ALL
PURPOSE PLANTER BOX ADAPTER.
MODEL No. TIA100PB.
3 PLANTER DRAINAGE CELL
4 SPS PARAPET DRAIN. MODEL No.
PD100CS.
SWD DP
65 6.2L/S
100
O/F FAL
L
SWD 65
65 PIPEWORK CAST IN SLAB.
150mm x 150mm (STRUCTURE TO CONFIRM)
OVERFLOW SWIP.
65
PDO 65mm OVERFLOW RAISED 20mm
65
3 ABOVE TRENCH GRATE BASE CUSTOM EAVES GUTTER
SPS TRUFLO 100mm RWO WITH FALL 1 650mm WIDE x 165mm HIGH.
FLAT GRAT AND MEMBRANE 65mm OUTLET
CLAMP. MODEL No. TIA100F2. POOL RWO
BELOW 65
100mm NON-SLIP HEEL
PIPEWORK CAST IN SLAB. GUARD TRENCH DRAIN WITH
(STRUCTURE TO CONFIRM) TERRACE S/S GRATE. 65mm OUTLETS
THRESHOLD DRAIN.
(REFER TO ARCH) FALL
RETREAT
RL 68400
HP
D)
HT (SD CUSTOM EAVES GUTTER
SKYLIG 2.0L/S
FALL DP
WITH 1.0m SPREADER 650mm WIDE x 165mm HIGH.
3° ROO
100
150mm x 150mm
DN
OVERFLOW SWIP.
F
150mm x 150mm 3
4
LIFT DP
4.1L/S
OVERFLOW SWIP. 100
4
100 SWD DP
PIPEWORK CAST IN SLAB. 4.1L/S
100 HP 100
10
0
FALL
FALL
(STRUCTURE TO CONFIRM) B REVISED BA ISSUE LN 30.10.23
PIPEWORK CAST IN SLAB. CUSTOM EAVES GUTTER
TERRACE SKYLIGHT (SDD)
650mm WIDE x 165mm HIGH.
(STRUCTURE TO CONFIRM) A BA ISSUE HB 25.10.23
RL 68400
YOGA
DP 2.0L/S
THRESHOLD DRAIN. WITH 1.0m SPREADER DD1 DESIGN DEVELOPMENT ISSUE LN 03.07.23
(REFER TO ARCH) PIPEWORK CAST IN 100
3 DP
SLAB. (STRUCTURE 4.9L/S
100
100 100 TO CONFIRM)
FALL SKYLIGHT (SDD)
4 4 Level 3, 39 Sherwood Road,
3 4 3
Toowong, QLD 4066
PH: (07) 3876 0088
SWD [email protected]
100 www.brwhydraulics.com.au
QBCC LIC. No. 15067628
150mm x 150mm 150mm x 150mm
OVERFLOW SWIP. OVERFLOW SWIP.
UPPER FLOOR PLAN / DRAINAGE
SCALE 1:100
PROPOSED STORMWATER
DESIGN FOR RESIDENTIAL
DEVELOPMENT
36 ENTERPRISE STREET,
SUNSHINE BEACH, QLD, 4567
UPPER FLOOR PLAN
DRAINAGE
B. NIKOLAJEVS
LN (QBCC LICENCE N° 15058052) JUNE 2023
As Shown
@ A1
20190 H04 B
Page 15
DRAINAGE PLAN No.
SPECIFIC NOTES
1 SPS TRUFLO 100mm 90° RWO WITH
ALL PURPOSE PLANTER BOX
ADAPTER. MODEL No. TIA100/90PB.
2 SPS TRUFLO 100mm RWO WITH ALL
PURPOSE PLANTER BOX ADAPTER.
MODEL No. TIA100PB.
3 PLANTER DRAINAGE CELL
4 SPS PARAPET DRAIN. MODEL No.
PD100CS.
DP
2.0L/S
100
HP
CUSTOM EAVES GUTTER
650mm WIDE x 90mm HIGH.
A BA ISSUE HB 25.10.23
DP DD1 DESIGN DEVELOPMENT ISSUE LN 03.07.23
2.0L/S
100
Level 3, 39 Sherwood Road,
Toowong, QLD 4066
PH: (07) 3876 0088
[email protected]
www.brwhydraulics.com.au
QBCC LIC. No. 15067628
UPPER FLOOR PLAN / DRAINAGE
SCALE 1:100
PROPOSED STORMWATER
DESIGN FOR RESIDENTIAL
DEVELOPMENT
36 ENTERPRISE STREET,
SUNSHINE BEACH, QLD, 4567
UPPER FLOOR PLAN
DRAINAGE
B. NIKOLAJEVS
LN (QBCC LICENCE N° 15058052) JUNE 2023
As Shown
@ A1
20190 H05 A