2. existing stormwater flows

STORMWATER DRAINAGE
STRATEGY REPORT
140-204 WESTERN AVENUE WESTMEADOWS
FOR
SEPTEMBER 2014
Dalton Consulting Engineers Pty Ltd
255 Whitehorse Road
ABN 78 429 221 049
PO Box 349
F 61 3 9888 6880
Balwyn Victoria 3103
E info@dceprofile.com
Australia
W www.dceprofile.com
T 61 3 9888 6866
This report has been prepared solely for the benefit of Transpacific Industries Group
Ltd and Dalton Consulting Engineers Pty Ltd. No liability is accepted by this company
or any employee or sub-consultant of this company with respect to its use by any
other person.
This disclaimer shall apply notwithstanding that the report may be made available to
other persons for an application for permission or approval or to fulfil a legal
requirement.
Revision No.
8
Date:
September 2014
Description:
Stormwater Strategy Report v8
Prepared:
J Baumann
AN: 401053
Reviewed:
R Monkhouse
AN: 642233
Approved:
T Liakopoulos
AN: 883107
11911se2614G Stormwater Strategy V8
September 2014
i
Contents
1.
INTRODUCTION................................................................................................ 1
1.1.
1.2.
LOCATION AND ZONING.................................................................................. 1
SITE OVERVIEW ............................................................................................ 2
2.
EXISTING STORMWATER FLOWS .................................................................. 2
3.
DEVELOPED STORMWATER FLOWS............................................................. 4
3.1.
3.2.
3.3.
3.4.
3.5.
EXTERNAL CATCHMENTS ............................................................................... 4
MINOR FLOWS .............................................................................................. 5
MAJOR FLOWS .............................................................................................. 5
STORMWATER RETENTION ............................................................................. 6
STORMWATER TREATMENT SYSTEM ............................................................... 7
APPENDIX A—SUBJECT AREA ............................................................................. 8
APPENDIX B—EXISTING CONDITIONS CATCHMENTS AND FLOWS ................. 9
APPENDIX C—DEVELOPED CONDITIONS CATCHMENTS, FLOWS AND
RETENTION ........................................................................................................... 10
11911se2614G Stormwater Strategy V8
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ii
1. INTRODUCTION
This report has been prepared for Transpacific Industries Group Ltd to support the
rezoning of the subject site to Comprehensive Development Zone (CDZ). The report
outlines the strategy proposed to treat stormwater runoff from a proposed
development at 140-204 Western Avenue, Westmeadows.
This report demonstrates that stormwater drainage from the proposed development
on the subject site can be suitably drained and treated in accordance with both Hume
City Council and Melbourne Water requirements.
1.1.
Location and zoning
The subject site is located adjacent to Melbourne Airport. The Airport Environs
Planning Overlay does not impact the subject site. An aerial image of the subject
area is shown in Figure 1 and a larger image is included as Appendix A.
Figure 1—Property and Re-zone boundaries
11911se2614G Stormwater Strategy V8
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1
1.2.
Site overview
The property comprises a total area of 28.6 ha and is owned by Transpacific
Industries Group Ltd. Approximately 22.5 ha is proposed to be rezoned from FZ3 to
CDZ, 2.3 ha will become road reserves, and 3.8 ha will be reserves.
The property is located near Melbourne Airport and abuts Tullamarine Freeway to the
south, Wright Street to the east and Moonee Ponds Creek to the north. Victoria
Street, which is not constructed, forms the western boundary of the site. Western
Avenue traverses the southern portion of the site. The property has been used for
grazing purposes.
The subject site generally grades from the south-west to the north-east towards
Moonee Ponds Creek.
2. EXISTING STORMWATER FLOWS
The subject site drains to the north-east via overland flow to Moonee Ponds Creek.
Existing underground drainage within Western Avenue connects to a 600-mm
diameter drain in Wright Street. This drain discharges at the northern end of Wright
Street to an open earth channel which connects to the creek.
The responsible authorities for stormwater drainage are Hume City Council and
Melbourne Water. Council is responsible for drainage catchments up to 60 ha;
Melbourne Water is responsible for larger catchments, including any works within the
Moonee Ponds Creek Reserve.
Currently, stormwater runoff sheet flows from two catchments within the site, as
shown in Figure 3. A large-scale image of the existing stormwater catchments is
included in Appendix B. The pre-development 1-year, 10-year and 100-year average
recurrence interval (ARI) flows have been calculated using the Rational Method from
Australian Rainfall and Runoff (AR&R) and are detailed in Figure 2. Full calculations
are included in Appendix C.
Figure 2—Existing catchments and associated major and minor flows
Catchment
Catchment 1
Catchment 2
Total area
(ha)
10.1
35.1
11911se2614G Stormwater Strategy V8
September 2014
1-year ARI flow
(m3/s)
0.1
0.3
10-year ARI flow
(m3/s)
0.4
0.9
100-year ARI flow
(m3/s)
0.8
1.8
2
Figure 3—Existing condition stormwater catchments
11911se2614G Stormwater Strategy V8
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3
3. DEVELOPED STORMWATER FLOWS
The subject site is proposed to be rezoned to CDZ and will be developed for
industrial/commercial use. Figure 4 shows the future developed catchments at the
subject site. The developed catchments are similar to the existing catchments, but in
the developed condition, the boundary between the two catchments will change as a
result of site earthworks benching. The layout of stormwater drains shall be
incorporated into the road reserves with easement drains minimised where possible.
Figure 4—Developed stormwater catchments
3.1.
External catchments
As shown in Figure 4, an external, undeveloped catchment ‘downstream’ of
Developed Catchment 1 drains directly to Moonee Ponds Creek. This area is
proposed to become a reserve. As it will be undeveloped, stormwater from the
‘downstream’ catchment will continue to drain overland to Moonee Ponds Creek.
Developed Catchment 2 also extends beyond the boundary of the subject site. A
downstream sub-catchment of Developed Catchment 2 comprising 9.2 ha of land not
11911se2614G Stormwater Strategy V8
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4
owned by Transpacific Industries Group is external to the subject site. This land may
be rezoned and developed in the future. Retention of stormwater flows from this
adjacent land as well as treatment for it as fully developed have been included in the
stormwater strategy.
Tullamarine Freeway Reserve drains to the south and towards Steele Creek, not
through the subject site.
3.2.
Minor flows
The minor drainage system will be designed and constructed to Hume City Council
standards for a 10-year ARI. Developed 10-year flows have been calculated using
the Rational Method from AR&R and are detailed in Figure 5 and Appendix C.
In Developed Catchment 1, shown in yellow in Figure 4, the undeveloped reserve
downstream sub-catchment will continue to drain overland to Moonee Ponds Creek.
Within the re-zone area, minor flows (up to and including the 10-year ARI event) from
Developed Catchment 1 will be conveyed via a piped drainage system. Flows equal
to and less than the 1-year (Q1) flows will be conveyed via a drainage pipe to a
proposed wetland located east of the subject site in Melbourne Water’s Tarnuk
Reserve, as shown in Figure 4 and Figure 7. Flow greater than the 1-year flow will
surcharge from the pipe and drain directly to Moonee Ponds Creek.
In Developed Catchment 2, shown in blue in Figure 4, minor flows (up to and
including the 10-year ARI event) from the developed areas will be conveyed via a
piped drainage system as shown in Figure 7. Flows equal to and less than the 1-year
(Q1) flows will be conveyed via drainage pipes to a proposed wetland located east of
the subject site in Melbourne Water’s Tarnuk Reserve, as shown in Figure 4 and
Figure 7. Flow greater than the 1-year flow will surcharge from the pipe and follow
the existing overland flow path to Moonee Ponds Creek.
Figure 5—Developed catchments and flows
Catchment
Developed Catchment 1
Developed Catchment 2
(Subject site and external downstream)
3.3.
Developed
area (ha)
5.8
1-year
ARI flow
(m3/s)
0.2
10-year
ARI flow
(m3/s)
0.6
100-year
ARI flow
(m3/s)
1.3
31.1
1.2
3.0
6.3
Major flows
When the capacity of the minor drainage system within Catchments 1 and 2 is
exceeded by flows in excess of 10-year ARI event, overland flow will occur in both
catchments. Road reserves and open channel drainage reserves will be designed to
safely convey up to 100-year ARI events through the development without exceeding
Melbourne Water’s safety criteria for maximum depth and velocity.
In Catchment 1, overland flows in excess of 10-year ARI flows shall be directed
overland to Moonee Ponds Creek. In Catchment 2, overland flows in excess of 10-
11911se2614G Stormwater Strategy V8
September 2014
5
year ARI flows shall drain overland to Moonee Ponds Creek via the existing gully in
the external downstream catchment. Major event flows are shown in Figure 5.
3.4.
Stormwater retention
The approximate volume of required storage has been calculated using Boyds
Method and is summarised in Figure 6 and detailed in Appendix C. Stormwater
retention will be provided (as shown in Figure 7) for 1-year flow from Catchment 2.
The retention storage will be located in the airspace overhead of the water quality
treatment system to minimise the footprint of the off-site stormwater treatment.
Approximately 4,500 m3 of storage are available in the airspace overhead of the
water quality treatment.
Melbourne Water has provided the 100-year flood levels along Moonee Ponds
Creek. The subject land is not affected by inundation, as shown in Figure 7. A creek
buffer zone, external to the re-zoned land, provides open space adjacent to the creek
in accordance with Melbourne Water guidelines.
Figure 6—Required retention storage volume
Catchment
Catchments 1 and 2
3.5.
Existing 1-year
ARI flow (m3/s)
0.4
Developed 1-year
ARI flow (m3/s)
1.4
Approximate volume of
required retention (m3)
2,025
Stormwater treatment system
The current stormwater quality objectives as set out in the Urban Stormwater—Best
Practice Environmental Guidelines (CSIRO, 2000) are:
•
•
•
•
Total Suspended Solids (TSS)—80% reduction
Total Phosphorus (TP)—45% reduction
Total Nitrogen (TN)—45% reduction
Gross Pollutants (litter)—70% reduction
The stormwater quality treatment is proposed to comprise a sedimentation basin,
wetland and bioretention system located within Melbourne Water’s Tarnuk Reserve.
A total treatment area of 7,000 m2 has been preliminarily sized using the Model for
Urban Stormwater Improvement Conceptualisation (MUSIC), version 6.0.1. The
stormwater quality treatment is shown in Figure 7 and included as Appendix D.
11911se2614G Stormwater Strategy V8
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6
Figure 7—Stormwater treatment and retention
11911se2614G Stormwater Strategy V8
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7
APPENDIX A—Subject area
11911se2614G Stormwater Strategy V8
September 2014
8
APPENDIX B—Existing conditions catchments and
flows
11911se2614G Stormwater Strategy V8
September 2014
9
PEAK FLOW CALCULATION SHEET
(RATIONAL METHOD)
JOB NAME:
JOB No.:
Western Ave
11911
Based on GAA Engineering design and construction manual Table 16
C'10
Rural (RUZ)
Industrial
Fraction
Impervious
Fraction
Impervious
0.1
COEFFICIENT OF RUNOFF
C1
C2
C10
C5
C100
C'10
From the GAA Engineering design and construction manual Table 17
0.16
0.187
0.199
0.234
0.223
0.281
=
0.9
COEFFICIENT OF RUNOFF
C1
C2
C10
C5
C100
C200
0.1 + 0.0133 (10i1 -25)
0.16
0.661
0.702
0.826
0.785
0.991
1.033
given as for above
10i1 is the 10-year, 1-hour duration rainfall intensity
ARI table for
DURATION
5Mins
6Mins
10Mins
20Mins
30Mins
1Hr
2Hrs
3Hrs
6Hrs
12Hrs
24Hrs
48Hrs
72Hrs
1 Year
47.9
44.6
36.3
26.3
21.2
14.2
9.31
7.26
4.73
3.03
1.87
1.09
0.78
2 years
5 years
64.1
59.7
48.4
34.9
28.1
18.7
12.2
9.48
6.12
3.9
2.42
1.43
1.02
10 years
88.6
82.6
66.6
47.5
38.1
25.1
16.1
12.3
7.79
4.92
3.09
1.89
1.37
105
98.2
79
56.1
44.8
29.4
18.7
14.2
8.85
5.56
3.52
2.19
1.6
20 years 50 years
128
119
95.5
67.5
53.8
35.2
22.2
16.7
10.3
6.44
4.1
2.59
1.91
100 years
160
149
119
83.9
66.7
43.4
27
20.3
12.3
7.66
4.92
3.16
2.35
187
174
139
97.5
77.4
50.1
31
23.1
13.9
8.63
5.57
3.63
2.71
37.675 South
144.875 East
Job Description:
Job Number:
Compiled by: Western Avenue
11911
JMB
Location and ARI
WesternAve_1
1‐year pre‐development
Date:
a
2.651540
26‐Jun‐14
b
c
d
e
f
‐0.598621 ‐0.019480 0.011766 ‐0.001946 ‐0.000769
g
0.000138
C
Ae
ƩAe
I1
Q1 Total
ha
10.1
0.19
ha
1.893
ha
1.893
mm/hr
26.734
m3/s
0.1
41
35.1
0.19
6.579
6.579
17.743
0.3
41
45.2
0.19
8.472
8.472
17.743
0.4
Outlet of
Length
Overland velocity
Tc
Area
C1All
m
400
m/s
0.5
mins
19
C2All
1050
0.5
All
1200
0.5
G:\Designdata\11900\11911-Western Ave Tullamarine\MUSIC\11911jn2614G_RationalFlows
1
Job Description:
Job Number:
Compiled by: Western Avenue
11911
JMB
Location and ARI
WesternAve_10
10‐year pre‐development
Date:
a
3.382109
26‐Jun‐14
b
c
d
e
f
‐0.634951 ‐0.035928 0.008127 0.000906 ‐0.000189
g
‐0.000034
C
Ae
ƩAe
I10
Q10 Total
ha
10.1
0.23
ha
2.366
ha
2.366
mm/hr
57.116
m3/s
0.4
41
35.1
0.23
8.223
8.223
37.272
0.9
41
45.2
0.23
10.590
10.590
37.272
1.1
Outlet of
Length
Overland velocity
Tc
Area
C1All
m
400
m/s
0.5
mins
19
C2All
1050
0.5
All
1200
0.5
G:\Designdata\11900\11911-Western Ave Tullamarine\MUSIC\11911jn2614G_RationalFlows
1
Job Description:
Job Number:
Compiled by: Western Avenue
11911
JMB
Location and ARI
WesternAve_100
100‐year pre‐development
Date:
a
3.914350
b
c
d
e
‐0.661794 ‐0.048348 0.005543 0.003007
26‐Jun‐14
f
0.000219
g
‐0.000157
C
Ae
ƩAe
I100
Q100 Total
ha
10.1
0.28
ha
2.840
ha
2.840
mm/hr
99.284
m3/s
0.8
41
35.1
0.28
9.868
9.868
64.013
1.8
41
45.2
0.28
12.707
12.707
64.013
2.3
Outlet of
Length
Overland velocity
Tc
Area
C1All
m
400
m/s
0.5
mins
19
C2All
1050
0.5
All
1200
0.5
G:\Designdata\11900\11911-Western Ave Tullamarine\MUSIC\11911jn2614G_RationalFlows
1
APPENDIX C—Developed conditions catchments,
flows and retention
11911se2614G Stormwater Strategy V8
September 2014
10
PEAK FLOW CALCULATION SHEET
(RATIONAL METHOD)
JOB NAME:
JOB No.:
Western Ave
11911
Based on GAA Engineering design and construction manual Table 16
C'10
Rural (RUZ)
Industrial
Fraction
Impervious
Fraction
Impervious
0.1
COEFFICIENT OF RUNOFF
C1
C2
C10
C5
C100
C'10
From the GAA Engineering design and construction manual Table 17
0.16
0.187
0.199
0.234
0.223
0.281
=
0.9
COEFFICIENT OF RUNOFF
C1
C2
C10
C5
C100
C200
0.1 + 0.0133 (10i1 -25)
0.16
0.661
0.702
0.826
0.785
0.991
1.033
given as for above
10i1 is the 10-year, 1-hour duration rainfall intensity
ARI table for
DURATION
5Mins
6Mins
10Mins
20Mins
30Mins
1Hr
2Hrs
3Hrs
6Hrs
12Hrs
24Hrs
48Hrs
72Hrs
1 Year
47.9
44.6
36.3
26.3
21.2
14.2
9.31
7.26
4.73
3.03
1.87
1.09
0.78
2 years
5 years
64.1
59.7
48.4
34.9
28.1
18.7
12.2
9.48
6.12
3.9
2.42
1.43
1.02
10 years
88.6
82.6
66.6
47.5
38.1
25.1
16.1
12.3
7.79
4.92
3.09
1.89
1.37
105
98.2
79
56.1
44.8
29.4
18.7
14.2
8.85
5.56
3.52
2.19
1.6
20 years 50 years
128
119
95.5
67.5
53.8
35.2
22.2
16.7
10.3
6.44
4.1
2.59
1.91
100 years
160
149
119
83.9
66.7
43.4
27
20.3
12.3
7.66
4.92
3.16
2.35
187
174
139
97.5
77.4
50.1
31
23.1
13.9
8.63
5.57
3.63
2.71
37.675 South
144.875 East
Job Description:
Job Number:
Compiled by: Western Avenue
11911
JMB
1‐year developed
Date:
26‐Jun‐14
Location and ARI
WesternAve_1
a
b
c
d
2.651540 ‐0.598621 ‐0.019480 0.011766
e
‐0.001946
f
‐0.000769
g
0.000138
C
Ae
SAe
I1
Q1 Total
ha
3.833
mm/hr
22.898
m /s
0.2
Outlet of
Length
Velocity
Tc
Area
C1Industrial
m
600
m/s
0.5
mins
26
ha
5.8
0.661
ha
3.833
C2 NorthIndustrial and Reserve
300
0.5
16
6.4
0.661
4.229
4.229
29.355
0.3
C2 SouthIndustrial and Reserve
800
0.5
33
15.5
0.661
10.243
10.243
20.195
0.6
C2Internal total
800
0.5
33
21.9
0.661
14.472
14.472
20.195
0.8
C2Internal and External
1200
0.5
33
31.1
0.661
20.552
20.552
20.195
1.2
All
1200
0.5
33
36.9
0.661
24.384
24.384
20.195
1.4
G:\Designdata\11900\11911-Western Ave Tullamarine\MUSIC\11911jn2614G_RationalFlows
3
1 of 1
Job Description:
Job Number:
Compiled by: Western Avenue
11911
JMB
10‐year developed
Date:
26‐Jun‐14
Location and ARI
WesternAve_10
ARI
10
a
b
c
d
3.382109 ‐0.634951 ‐0.035928 0.008127
e
0.000906
f
‐0.000189
g
‐0.000034
C
Ae
SAe
I10
Q10 Total
ha
4.791
mm/hr
48.605
m /s
0.6
Outlet of
Length
Velocity
Tc
Area
C1Industrial
m
600
m/s
0.5
mins
26
ha
5.8
0.826
ha
4.791
C2 NorthIndustrial and Reserve
300
0.5
16
6.4
0.826
5.287
5.287
63.002
0.9
C2 SouthIndustrial and Reserve
800
0.5
33
15.5
0.826
12.803
12.803
42.657
1.5
C2Internal total
800
0.5
33
21.9
0.826
18.090
18.090
42.657
2.1
C2Internal and External
1200
0.5
33
31.1
0.826
25.690
25.690
42.657
3.0
All
1200
0.5
33
36.9
0.826
30.481
30.481
42.657
3.6
G:\Designdata\11900\11911-Western Ave Tullamarine\MUSIC\11911jn2614G_RationalFlows
3
1 of 1
Job Description:
Job Number:
Compiled by: Western Avenue
11911
JMB
Location and ARI
WesternAve_100
100‐year developed
Date:
26‐Jun‐14
ARI
100
a
3.914350
b
‐0.661794
c
‐0.048348
d
0.005543
e
0.003007
f
0.000219
g
‐0.000157
Outlet of
Length
Velocity
Tc
Area
C
Ae
SAe
I100
Q100
C1Industrial
m
600
m/s
0.5
mins
26
ha
5.8
0.991
ha
5.749
ha
5.749
mm/hr
84.104
m3/s
1.3
C2 NorthIndustrial and Reserve
300
0.5
16
6.4
0.991
6.344
6.344
109.867
1.9
C2 SouthIndustrial and Reserve
800
0.5
33
15.5
0.991
15.364
15.364
73.551
3.1
C2Internal total
800
0.5
33
21.9
0.991
21.708
21.708
73.551
4.4
C2Internal and External
1200
0.5
33
31.1
0.991
30.827
30.827
73.551
6.3
All
1200
0.5
33
36.9
0.991
36.577
36.577
73.551
7.5
G:\Designdata\11900\11911-Western Ave Tullamarine\MUSIC\11911jn2614G_RationalFlows
1
BOYDS FORMULA 1-YEAR REQUIRED RETENTION
All future industrial areas
26‐Jun‐14
Input by user
Calculated by spreadsheet
Catchment Area (A) =
Runoff Coefficient (1-year) =
1-year Effective Catchment Area = ∑CA =
Restricted outflow requirement =
36.9 ha
0.661
24.38 ha
3
0.40 m /s
Storage requirement is highest value of S max calculated in the table below
Critical storm duration is the storm duration when S max occurs
Storm Duration
1-year
Ip
3
(min)
Intensity (mm/hr) (m /s)
5
6
10
20
30
60
120
180
360
720
1440
2880
4320
47.9
44.6
36.3
26.3
21.2
14.2
9.31
7.26
4.73
3.03
1.87
1.09
0.78
3.24
3.02
2.46
1.78
1.44
0.96
0.63
0.49
0.32
0.21
0.13
0.07
0.05
Qp
(m3/s)
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
Max Storage
V1
(m3)
Smax
(m3)
973
853.3
1,088
943.5
1,475
1,235.3
2,138
1,657.7
2,585
1,864.8
3,463
2,022.6
4,540
1,660.4
5,311
990.9
6,920 ‐1,719.7
8,866 ‐8,413.8
10,944 ‐23,616.3
12,758 ‐56,362.1
13,694 ‐89,985.7
2,022.6
3
m