Original source · versioned page text
1909-13367 SRA referral response approved docs
Attached to the e-mail SARA Referral agency response – with conditions - MCU19/0114 & RAL19/0027.
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FFOR
OR AAPPROVAL
PPROVAL
NNOT
OTT FOR
FOR CONSTRUCTION
FO CCONS
ONSTRU
ONSTRUUCTI
UCTI
CTIO
TION
ON
Provide development
setback from the
railway corridor
generally in
accordance with this
plan
VIEW 4
VIEW 7 4.03
VIEW 8
4.06
4.07
SS11
SS14
4.02
4.02 VIEW 5
VIEW 6 4.04
4.05
SS13 SS12
4.02 4.02
SITE CONTEXT
SITE CONTEXT STUDY
STUDY 1:2500
11:250
:250
2 0 @ A3
A3
• THIS DRAWING HAS BEEN PRODUCED BASED
ISSUE DATE DESCRIPTION ON INFORMATION SUPPLIED BY OTHERS. WHILE PROJECT JAREDPOOLEDESIGN DRAWN CB DRAWING - SITE CONTEXT STUDY
A 01.08.19 ISSUED FOR APPROVAL
ALL ATTEMPTS HAVE BEEN MADE TO ENSURE THE
ACCURACY OF THE DRAWING JARED POOLE. PROPOSED NEW DEVELOPMENT DATE JAN. 2019 DRAWING No. ISSUE
BP1074/SK4.01 A
DESIGN WILL NOT BE HELD RESPONSIBLE FOR
THE ACCURACY OF THE INFORMATION PROVIDED. AT LEVEL 1 33 ELKHORN AVENUE SCALE 1:2500 @ A3
• THE WORKS DESCRIBED ON THIS AND SURFERS PARADISE, Q. 4217 AUSTRALIA
ACCOMPANYING DRAWINGS ASSOCIATED WITH
THIS PROJECT PRODUCED BY JARED POOLE.
LOT 2 & 3 MYALL STREET, COOROY, QLD PO BOX 42
DESIGN ARE COVERED BY COPYRIGHT. THE WORKS FOR ISLE OF CAPRI, Q. 4217 AUSTRALIA
DESCRIBED ARE APPLICABLE TO THE PROJECT TEL 07 5527 5300
SITE ONLY AND MUST NOT BE USED FOR ANY
OTHER PURPOSE. WORKS CANNOT BE COPIED OR
GEMLIFE EMAIL [email protected]
REPRODUCED BY ANY MEANS WITHOUT WRITTEN WEB WWW.JPD.COM.AU
PERMISSION OF JARED POOLE. DESIGN.
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Full text of pages 2 to 141 (of 146)
Page 2
GEMLIFE
Proposed Reconfiguration
Lots 1, 2 & 3 on SP1159864
Myall St, Cooroy
SUNSH
N
IC
EOAST
PO Box 1073, Buddina QLD 4575 Ph: (07) 5437 8555
[email protected] ABN: 91 615 043 251
www.dsqsurvey.com ACN: 615 043 251
WESTERN
DOWNS
A3 1:2500
13422-PRO-01C
Page 3
21 22 23 24
12 13 14 15 16 17 18 19 20
09 10 11 25
06 07 08
04 05
26
96 105 114 124 134 144 190 191 27
01 81 88
115 135 145 28 29
77 97 106 125
82 89 154 163 172 181
75 30
78 98 107 116 126 136 146
83 90 155 164 173 182
76 31
79 99 108 117 127 137 147 206
84 91 156 165 174 183
32
100 109 118 128 138 148 204
74 80 85 92 157 166 175 184 200 33
101 110 119 129 139 149
73 86 93 158 167 176 185 209 34
214 212 210
72 120 130 140 150
102 111 35
87 94 159 168 177 186
71
103 112 121 131 141 151 221 36
224
95 160 169 178 187 220
122 132 142 152 37
104 113
161 170 179 188
68 123 133 143 153 38
67 162 171 180 189
66 39
65
64 40
63
62 41
61 42
60 59 58 57 56 55 54 53 52 43
51 50 49 48 47 46 45 44
STREET
MYALL
Provide earthworks setback from
the railway corridor generally in
PRELIMINARY
accordance with thisEARTHWORKS PLAN
plan PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 4
LEGEND YIELD
FOR APPROVAL STANDARD LOTS - 14m x 21m
TOTAL NUMBER OF LOTS 245
NOT FOR CONSTRUCTION
VILLA LOTS - 13m x 21m
OPTIONS GAIN/LOSS
RELOCATABLE SALES SHOWROOM 0
COMMUNITY LANDSCAPING RV COMPOUND 0
BOCCE COURT 0
G O L F C O U R S E DASHED LINE OF CUT EXISTING VEGETATION
18TH
12TH GREEN FILL
CUT RETAINING WALL ZONE, REFER CIVILS
TEE
PUTTING
GREEN
20 LOTS 9 LOTS
PROPOSED 13 14 15 16 17 18 19 20
CLUB HOUSE 21 22 23 24 25 26 27 28 29
BOUNDARY LINE 12
GOLF CLUB 11 (LAWN BOWL ON
10
09 FIRST LEVEL)
08
07 PAD RL 118.0
111.0
06 123 124 145 146 167 204 225 226 245 30
05 104
04 103
03 105 122 125 5 6 224 227 244
4 86 87 144 147 166 205 31
02 102
126 143 148 165 168 185 186 203 206 223 228 243
1ST 01 106 32
78 88 121
TEE 85 101
202
89 107 120 127 169 184 187 229 242
84 33
9 LOTS 17 LOTS 20 LOTS 22 LOTS 142 149
22 LOTS 164 207
22 LOTS 222
11
77 100
3.0
79 170 183 188 201
90 108 141 150 163 208 221 230 241
76 80
83 99 119 128
20 LOTS 34
SUMMER
MANAGERS UNIT 129
200
10 LOTS HOUSE
12
91 109 171 182 189 231 240
0.0
82 118 140 151 162 209 220
75
11
4.0
98
172 181 190 199 35
11
130 139 152 161 210 219
5.0
11
110 232 239
92
18 LOTS 18 LOTS
6.0
74
121.0
81 97 117 3 36
131
11
73 111
7.
93 173 180 191 198 233 238
0
116 138 153 160 12
0.
211 218
96
0
37
72 132 137 154 159 174 179 192 197 212 217
94 112 234 237
11
Pedestrian pathway 95
3 11 11
118
9.0
11 8.0 9.0
6.0
38
.0
PROPOSED 71 115 11
133
10
7.0
BRIDGE
connction to Myall Street
6.
113
0
70 114 136 11
4.0 155 115.0 158 175 178 193 196 213 216 235 236 39
11
11 3.0
1.
10
10 0
2
9.
7.
0
69 10 134 135 156 157 176 177 194 195 214 215
0
8. 11
0 2.0
68 110.0
40
67
1ST 15 LOTS 66
65 8 41
GREEN 64 42
RV 63 43
62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44
COMPOUND
1800m2 23 LOTS
DRIVEWAY MANAGERS
EASEMENT SALES WORKSHOP
SHOWROOM EXISTING VEGETATION
EMERGENCY
SITE ACCESS
BOCCE COURT MY A L L S T R E E T
PROPERTY DESCRIPTION
LOT 2 & 3 MYALL STREET COOROY QLD, 4563
LOT 2 & 3 ON SP115864
PARISH OF TEWANTIN
COUNTY OF MARCH
SITE AREA - 11.299 Ha
MASTER PLAN 1:1500 @
1500 A3
@ A3
SITE COVER - TBA%
• THIS DRAWING HAS BEEN PRODUCED BASED
ISSUE DATE DESCRIPTION ON INFORMATION SUPPLIED BY OTHERS. WHILE PROJECT JAREDPOOLEDESIGN DRAWN CB DRAWING - MASTER PLAN
AJ
K
01.08.19
29.03.19
11.04.19
GOLF
ISSUEDCLUB
FORADDED
APPROVAL
LAYOUT AMENDED
ALL ATTEMPTS HAVE BEEN MADE TO ENSURE THE
ACCURACY OF THE DRAWING JARED POOLE. PROPOSED NEW DEVELOPMENT DATE JAN. 2019 DRAWING No. ISSUE
BP1074/SK2.01 RA
DESIGN WILL NOT BE HELD RESPONSIBLE FOR
THE ACCURACY OF THE INFORMATION PROVIDED. AT NORTH LEVEL 1 33 ELKHORN AVENUE SCALE 1:1500 @ A3
L 10.05.19 LAYOUT UPDATED, LEVELS ADDED
• THE WORKS DESCRIBED ON THIS AND SURFERS PARADISE, Q. 4217 AUSTRALIA
M
N
04.06.19
06.09.19
LAYOUT UPDATED, CIVIL INFO ADDED
INTERNAL DRIVEWAY NETWORK UPDATED.
ACCOMPANYING DRAWINGS ASSOCIATED WITH
THIS PROJECT PRODUCED BY JARED POOLE.
LOT 2 & 3 MYALL STREET, COOROY, QLD PO BOX 42
O 15.11.19 RFI RESPONSE
DESIGN ARE COVERED BY COPYRIGHT. THE WORKS FOR ISLE OF CAPRI, Q. 4217 AUSTRALIA
DESCRIBED ARE APPLICABLE TO THE PROJECT TEL 07 5527 5300
P
Q
19.11.19
20.11.19
LAYOUT AMENDED, SITE BOUNDARY AMENDED.
CARPARKING AMENDED
SITE ONLY AND MUST NOT BE USED FOR ANY
OTHER PURPOSE. WORKS CANNOT BE COPIED OR
GEMLIFE EMAIL [email protected]
R 03.12.19 SITE BOUNDARY AMENDED
REPRODUCED BY ANY MEANS WITHOUT WRITTEN WEB WWW.JPD.COM.AU
PERMISSION OF JARED POOLE. DESIGN.
Page 5
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[OCR of page images]
PLANS AND DOCUMENTS
referred to in the REFERRAL
AGENCY RESPONSE
SARA ref: 1909-13367 SRA
Date:
Queensland
Government
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Page 6
Stormwater Management Report Proposed Relocatable Home Park 122 & 144 Myall St, Cooroy Lots 2 & 3 on SP115864 For: Gemlife 18 December 2019 Ref: S19-007 18 December 2019 Stormwater Management Report 1 S19-007 122 & 144 Myall St, Cooroy
Page 7
DO C UM ENT I NFO RM AT IO N
Client Contact: Gemlife
Project Name: Stormwater Management Report for
122 & 144 Myall St, Cooroy
Westera Partners Ref: S19-007
Westera Partners Contact:
Justin Tunsted Phone: 07 5571 1599
Email: [email protected]
Bret Arthur Email: [email protected]
Certified for Issue by:
Bret Arthur RPEQ 4384
18 December 2019
Document Control:
Revision Author Approved for Issue Date
Revision 0 J. Tunsted B. Arthur 16/08/2019
Revision 1 J. Tunsted B. Arthur 18/12/2019
This report has been prepared for Gemlife for the purpose of accompanying a Development
Application for above address. This report must only be used by Gemlife for this purpose and must
not be used or relied upon by any other person for any other purpose.
The assessment, conclusions or recommendations in this report are based on conditions encountered
and information received at the time of preparing the report and may not be relied upon as site
conditions or operations vary over time.
Stormwater Management Report 2
S19-007 122 & 144 Myall St, Cooroy
Page 8
CO NT E NT S
1 Introduction ............................................................................................................................ 5
2 Site Description ..................................................................................................................... 5
2.1 Location and Land Use ............................................................................................................ 5
2.2 Lawful Point of Discharge ........................................................................................................ 6
2.3 External Catchment ................................................................................................................. 6
2.4 Flooding ................................................................................................................................... 6
3 Stormwater Quantity Management ...................................................................................... 6
3.1 Existing Catchment and Site Drainage .................................................................................... 6
3.1.1 Existing Hydrology ................................................................................................................... 7
3.2 Proposed Developed Site Drainage ........................................................................................ 8
3.3 Existing and developed site comparison ................................................................................. 8
3.4 On site Detention (OSD) .......................................................................................................... 9
3.5 Waterway Stability ................................................................................................................. 11
3.6 Critical Storm Durations ......................................................................................................... 12
4 Stormwater Quality Management ....................................................................................... 13
4.1 Operational Phase ................................................................................................................. 13
4.2 Stormwater Quality Treatment solution ................................................................................. 13
4.3 Construction Phase ............................................................................................................... 15
4.3.1 Erosion and Sediment Control ............................................................................................... 15
4.3.2 Maintenance and Monitoring Requirements .......................................................................... 16
5 Conclusion ........................................................................................................................... 18
6 Appendices ..............................................................................................................................
6.1 Appendix AA – Erosion Hazard Assessment ....................................................................... AA
6.2 Appendix AB – MUSIC details .............................................................................................. AB
6.3 Appendix AC – Engineering Drawings ................................................................................. AC
FIG U R E S
Figure 1 – Indicative Site location (NearMap 2019) ..................................................................... 5
Figure 2 - XPSTORM model layout. ............................................................................................. 9
Figure 3 – MUSIC Model & Pollutant load reductions ................................................................ 14
Stormwater Management Report 3
S19-007 122 & 144 Myall St, Cooroy
Page 9
T AB LE S
Table 1 – Existing site catchment summary.................................................................................. 7
Table 2 – Developed site catchment summary ............................................................................. 8
Table 3 – Existing & Developed site peak flow rates. ................................................................... 9
Table 4 – Detention details.......................................................................................................... 10
Table 5 – Mitigated peak flow rates from the developed site ...................................................... 11
Table 6 – Individual mitigated catchment discharge ................................................................... 12
Table 7 – Critical Durations ......................................................................................................... 12
Table 8 – Catchment Summary / Treatment Details ................................................................... 14
Table 9 – Pollutant load reductions achieved ............................................................................. 15
Table 10 – Pollutants typically generated during the construction phase ................................... 15
Table 11 – Maintenance of ESC measures ................................................................................ 17
Stormwater Management Report 4
S19-007 122 & 144 Myall St, Cooroy
Page 10
1 INT RO D UCT IO N
Westera Partners Pty Ltd has been commissioned by Gemlife to prepare a Stormwater Management
Report for the proposed relocatable home park to be constructed at 122 & 144 Myall St, Cooroy.
The new development comprises 245 relocatable dwellings, a shared clubhouse area and associated
hardstand and landscaped areas.
This report documents how stormwater runoff will be managed on site in accordance with Noosa Shire
Council’s (NSC) requirements.
2 SIT E D ES CR I PT IO N
2. 1 Loc at i on an d L an d U se
The site of the proposed development is located at 122 & 144 Myall St, Cooroy, with a real property
description of Lots 2 & 3 on SP115864. The proposed development area is approximately 107,320m2
and currently is undeveloped.
The site is crested in the centre of the site falling generally north and south towards the Cooroy golf
course. The average slope of the lot is approximately 6%.
The site is bound by Cooroy golf course to the north, east and south. Myall St borders the western
boundary. Refer to Figure 1 for the site location.
Figure 1 – Indicative Site location (NearMap 2019)
Stormwater Management Report 5
S19-007 122 & 144 Myall St, Cooroy
Page 11
2. 2 Law ful P oint of D is ch ar ge
The site has two identified lawful points of discharge (LPOD). LPOD 1 in the existing case generally
discharges via sheet and concentrated flow along the North West boundary to the Cooroy golf course.
LPOD 2 in the existing case generally discharges via sheet and concentrated flow along the length of
the eastern boundary also to the Cooroy golf course.
The LPOD’s for the developed case are as follows.
LPOD 1, located at the northern side of the development shall discharge via a headwall via an
appropriately designed energy dissipation structure. The second LPOD is deemed to be at the south
eastern side of the development within the Cooroy golf course via a headwall and energy dissipation
structure.
It is proposed to split the internal developed catchments between the two LPOD’s (as detailed later in
the report).
2. 3 E xte rn a l Cat ch me nt
The development site has a significant external catchment which flows through the existing channel
from Myall St through the golf course from South to North. The size of the external catchment is
approximately 222ha with a percentage impervious of approximately 9.6%. This external catchment
has been assessed as part of the separate flood study as prepared by Westera Partners and is provided
separately. The existing channel is not proposed to be changed from the existing case. A bridge is
proposed to span the existing channel with a span such that creek will flow unimpeded underneath in
all design events up to the 1% AEP (Annual Exceedance Probability) design event. Please refer
separate Flood study and Appendix AC for details.
2. 4 Floo din g
The proposed site has had a detailed flood assessment conducted to assess the suitability of the
development for use and to ensure no adverse impact due to the development to neighbouring
properties. This report has been prepared by Westera Partners and is provided separately.
3 ST O RM W AT E R Q U AN T IT Y M AN AG EM E NT
The stormwater quantity analysis of the existing and developed site conditions has been undertaken
with reference to the requirements and procedure outlined by:
Queensland Urban Drainage Manual (QUDM)
Australian Rainfall and Runoff 2016 (AR&R 2016)
The following sections of the report discuss the proposed developments’ impact on stormwater flows
and compare them with the existing case to ensure a no worsening effect to downstream properties.
The XPStorm modelling program, utilising the “Laurenson” runoff routing method, has been used to
model the catchment characteristics to determine the stormwater flow discharge from the site for various
storm durations (5 minutes up to 3 hours typically) and Annual Exceedance Probabilities (AEP’s) from
1% to 1EY (Exceedances Per Year).
3. 1 E xi st i ng C at c hm ent a nd Si t e D r ain ag e
The existing catchment is undeveloped and has been considered pervious. The site is crested with
portions of the site falling north and south (to LPOD 1 and 2 respectively). The existing site catchment
characteristics are detailed in Table 1. Refer Appendix AC for extents of existing catchment.
Stormwater Management Report 6
S19-007 122 & 144 Myall St, Cooroy
Page 12
Table 1 – Existing site catchment summary
Details
Subcatchment
Catchment 1 Catchment 2 Catchment 3
Area 54,640m2 15,980m2 35,790m2
% impervious 0% 0% 0%
Slope 6.5% 6.5% 6.5%
3.1.1 E xi st i ng H yd rol og y
The XPStorm model has utilised “Laurenson’s” method to calculate the runoff hydrograph for each of
the design events. Below is a brief summary of the parameters used in the model.
Mannings Roughness
The developable site area is vegetated. The developable area is generally well grassed with some small
bushes. A high value for Mannings roughness has therefore been applied. The majority of the
impervious surfaces will be concrete and roof areas and therefore a single impervious roughness has
been applied. The values that have been adopted for Pervious and impervious areas are as follows:
Pervious Area n = 0.045
Impervious Area n = 0.014
Initial and Continuing Losses
The initial loss (IL) and continuing loss (CL) for pervious/undeveloped areas available from
ARRDatahub are shown below.
ARRDataHub IL = 32mm
ARRDataHub CL = 2.6mm/hr
The above values were sourced from ARRDatahub (for coordinates (-26.445, 152.897) on the 20 June,
2019).
The above IL and CL have been deemed too high for the site. The IL and CL that have been adopted
are listed below.
Adopted IL (Pervious) = 15mm
Adopted CL (Pervious) = 2.6mm/hr
Adopted IL (Impervious) = 1.0mm
Adopted CL (Impervious) = 0.0mm/hr
Preburst Depths
Stormwater Management Report 7
S19-007 122 & 144 Myall St, Cooroy
Page 13
Prebursts have not been deemed appropriate for urban and semi-urban situations as their use can
produce anomalies in the results.
Rainfall Temporal Patterns
XPStorm has incorporated the temporal patterns from ARR DataHub for the given site location (-26.445,
152.897) on the 20 June, 2019).
These temporal patterns have been used to determine the critical storm duration for each of the design
events 1% to 1EY.
3. 2 P ropo s ed D ev e lop ed Si t e D r ain ag e
The proposed development comprises 245 relocatable dwellings with a shared clubhouse. The
developed case results in an increased impervious area and decreased proportion of pervious
landscape area.
The site consists of three sub catchments. Each sub catchment will be directed to one of three LPOD.
Catchment 1 will be captured and directed to LPOD 1, while catchments 2 and 3 will be directed to
LPOD 2 and 3.
Table 2 below details the developed catchment characteristics. Refer Appendix AC for the extents of
the developed catchment.
Table 2 – Developed site catchment summary
Catchment BioBasin Catchments 1 and 4 BioBasin Catchment 2 BioBasin Catchment 3
Area 59,730m2 18,140m2 29,450m2
%
87% approx. 87% approx. 87% approx.
impervious
(LPOD 1) North of (LPOD 2) North-East of (LPOD 3) South-East of
Discharge
Development Site (See Development Site (See Development Site (See
location
Appendix AC for details) Appendix AC for details) Appendix AC for details)
Slope 1.5% 1.5% 1.5%
3. 3 E xi st i ng an d d ev e lop ed s it e comp a ri so n
The XPStorm modelling program Version 2018.1 was used to compute the above information, the
hydrological model adopted was the Laurensons Method. Figure 2 below depicts the model layout used
within XPStorm.
Stormwater Management Report 8
S19-007 122 & 144 Myall St, Cooroy
Page 14
Figure 2 - XPSTORM model layout.
The XPStorm modelling program has utilised all the above data to give an estimate of peak flow rates
for each AEP storm event for the existing site in table 3.
Table 3 – Existing & Developed site peak flow rates.
Peak Flow Rate (L/s)
AEP Storm
Event
Combined Existing Catchment Combined Developed Catchment
1EY 2610 3006
0.5EY 3837 3806
0.2EY 4239 4723
10% 5169 5628
5% 6397 6388
2% 7197 7207
1% 7786 7874
A comparison of the existing and developed peak flows as listed above indicates that there will be an
increase in peak stormwater flows from the developed site. From these comparisons it can be seen that
an On Site Detention (OSD) device is necessary to ensure that the peak stormwater flows exiting the
developed site do not cause a detrimental effect to downstream properties or infrastructure.
3. 4 O n sit e D et e nt io n ( O SD )
Runoff from the site is proposed to be captured and directed to one of three bioretention basins which
will act as OSD. Catchment 1 will drain to basin 1, catchment 2 will drain to basin 2 and catchment 3
will drain to basin 3. There will also be a fourth basin, however this will only treat a small portion of the
catchment for stormwater quality purposes. A highflow bypass will be in place for the fourth basin where
events in excess of the design event will bypass.
It is proposed that the combined flows from the three sub-catchments shall not exceed the peak flow of
the existing site. Table 4 details the proposed detention details.
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Table 4 – Detention details
Characteristic Detail
Elevation vs detention area Basin 1 (LPOD 1)
104.80m AHD – 1m2 – Orifice Invert Level
106.30m AHD – 2m2 – Top of Field Inlet
106.301m AHD – 550m2
107.30m AHD – 890m2 – Basin Overflow Level
Basin 2 (LPOD 2)
107.80m AHD – 1m2 – Orifice Invert Level
108.90m AHD – 1m2 – Top of Field Inlet
108.901m AHD – 500m2
110.20m AHD – 1,500m2 – Basin Overflow Level
Basin 3 (LPOD 3)
107.80m AHD – 1m2 – Orifice Invert Level
108.90m AHD – 1m2 – Top of Field Inlet
108.901m AHD – 500m2
110.08m AHD – 600m2 – Basin Overflow Level
Outlet details Basin 1 – 2 x outlets (610mm Ø orifice onto 825mm Ø RCP)
Highflow Weir – [email protected] AHD
Basin 2 – 160mm Ø orifice onto 225mm Ø PVC
Highflow Weir – [email protected] AHD
Basin 3 – 415mm Ø orifice onto 600mm Ø RCP
Highflow Weir – [email protected] AHD
Q100 Water Level and OSD Volume Basin 1 Peak Water Level –107.46m AHD_0.16m above top of
weir
Q100 Detention Volume = 720m3 @ peak water level
Basin 2 Peak Water Level – 109.94m AHD_0.26m below top of
weir
Q100 Detention Volume = 1200m3 @ peak water level
Basin 3 Peak Water Level – 110.22m AHD_0.14m above top of
weir
Q100 Detention Volume = 286m3 @ peak water level
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Table 5 shows the mitigating effect of the OSD on the developed sites peak flows. The mitigated site
shall decrease peak stormwater flows (when compared with the existing site) for all design events.
Therefore ensuring that the downstream environment will not experience an increase in peak
stormwater flow from the proposed development.
Table 5 – Mitigated peak flow rates from the developed site
Peak Flow Rate (L/s)
AEP Storm
Event
Combined Existing Catchment Combined Mitigated Catchment
1EY 2610 1652
0.5EY 3837 2021
0.2EY 4239 2063
10% 5169 2281
5% 6397 3051
2% 7197 4734
1% 7786 5516
The developed site has changed the proportions of area draining to each of the LPOD. In the existing
case approximately 71.2% of the total site is considered to drain LPOD 1 with the remaining 28.9%
draining to LPOD 2. The developed case splits this with approximately 56.6% draining to LPOD 1,
16.5% draining to LPOD 2 and 26.9% draining to LPOD 2. Despite this the peak flows discharging to
each LPOD have not been increased for any event up to the 1% AEP event.
3. 5 W ate rw a y St ab il it y
The proposed development is proposed LPOD shall discharge to existing waterways within Cooroy golf
course. This triggers the need for waterway stability within Appendix 2 of the SPP. Table B of Appendix
2 of the SPP states that the design objective for waterway stability management shown below.
“Limit the peak 1-year ARI event discharge within the receiving waterway to the pre-development peak
1-year ARI discharge” – SPP Appendix 2 Table B.
As shown below in table 6 the proposed stormwater detention modelling has shown that the 63.2% AEP
event peak discharge (equivalent to 1 year ARI) has been reduced to each waterway. It is therefore
deemed that the development is meeting the waterway stability design objective.
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Table 6 – Individual mitigated catchment discharge
AEP Peak Flow Rate (L/s)
Storm
Event Existing Mitigated Existing Mitigated Existing Mitigated
Catchment 1 Catchment 1 Catchment 2 Catchment 2 Catchment 3 Catchment 3
1EY 1333 1179 432 68 915 374
0.5EY 1972 1453 579 71 1292 425
0.2EY 2173 1500 677 74 1471 451
3. 6 Cr iti c al St o rm Du r at i ons
The critical durations for each event (modelled using XPSTORM) for the existing, developed and
mitigated scenarios are presented below in table 6.
Table 7 – Critical Durations
Critical Duration
AEP Storm
Event
Existing Developed Mitigated
1EY 30 Minute 10 Minutes 30 Minute
0.5EY 10 Minute 10 Minutes 30 Minute
0.2EY 10 Minute 10 Minutes 30 Minute
10% 10 Minute 15 Minutes 30 Minute
5% 10 Minute 15 Minutes 30 Minute
2% 10 Minute 10 Minutes 30 Minute
1% 10 Minute 10 Minutes 30 Minute
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4 ST O RM W AT E R Q U AL I T Y M AN AG EM ENT
NSC requires that new developments achieve the assessment benchmarks laid out in part 14 of the
Noosa Plan. Stormwater water quality specifically relates to Work Code I (Water Sensitive Design
Code). Accessible developments are required to meet the performance outcomes of the QLD state
planning policy, Appendix 2 SPP Code: Water Quality. The QLD state planning policy operational phase
stormwater management design objectives are triggered when:
(1) A material change of use for an urban purpose that involves premises 2500m2 or greater in size
and :
(a) Will result in six or more dwellings; or
(b) An impervious area greater than 25% of the net developable area.
(2) Reconfiguring a lot for urban purposes that involves premises 2500m 2 or greater in size and
will result in six or more lots.
*Taken directly from the QLD state planning policy Appendix 2 Table B.
4. 1 O pe r at io na l Ph a se
The proposed development requires a MCU and:
Has a developable area greater than 2500m 2 and
Will result in the creation of 6 or more dwellings and
Will result in an impervious area greater than 25% of the net developable area
The proposed development therefore triggers the requirement for stormwater quality management
(from NSC). These objectives are based upon the Queensland Governments State Planning Policy
(SPP July 2017) table B the reductions in mean annual load from unmitigated development (%) are
outlined below:
80% reduction in Total Suspended Solids (TSS)
60% reduction in Total Phosphorous (TP)
45% reduction in Total Nitrogen (TN)
90% reduction in Gross Pollutants > 5mm (GP)
Limit the peak 1 year ARI event discharge within the receiving waterway to the pre-development
peak 1 year ARI discharge.
The proposed development shall utilise bioretention basins in order to achieve the required pollutant
load reductions stipulated above to treat stormwater flows prior to discharge off site. Each proposed
catchment shall be directed to a bioretention basin.
The proposed layout of the stormwater treatment train in presented below in figure 3 and in Appendix
AC.
4. 2 Sto rmw at e r Q ua lit y T re at me nt so luti on
The developed site has been modelled using the stormwater quality modelling program MUSIC.
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The proposed site will have four major sub-catchments. The proposed treatment train will consist of
four bioretention basins, one for each sub-catchment.
Table 7 outlines the developed catchment details and the relevant treatment device.
The model layout is presented in Figure 3 below.
Table 8 – Catchment Summary / Treatment Details
Catchment
Sub-Catchment
BioBasin BioBasin BioBasin BioBasin
Catchment 1 Catchment 4 Catchment 2 Catchment 3
Area 56,980m2 2,750m2 18,140m2 29,450m2
% impervious 87% approx. 100% approx. 87% approx. 87% approx.
Bioretention Basin 1 Bioretention Basin 2 Bioretention Basin 3
Filter Area = 550m2 Bioretention Basin Filter Area = 500m2 Filter Area = 500m2
minimum 4 minimum minimum
Extended Detention Filter Area = 40m2 Extended Detention Extended Detention
Treatment minimum
Depth = 0.3m Depth = 0.3m Depth = 0.3m
device details
Area at the top of Extended Detention Area at the top of Area at the top of
Extended Detention Depth = 0.3m Extended Detention Extended Detention
Depth = 650m2 Filter Depth = 0.5m Depth = 600m2 Depth = 600m2
Filter Depth = 0.5m Filter Depth = 0.5m Filter Depth = 0.5m
Flow Route LPOD 1 LPOD 2 LPOD 3
Figure 3 outlines the treatment train’s effectiveness and the pollutant load reductions achieved from
MUSIC stormwater modelling program. A larger image is provided in Appendix AB.
Figure 3 – MUSIC Model & Pollutant load reductions
Table 8 outlines the treatment trains effectiveness.
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Table 9 – Pollutant load reductions achieved
Mean annual % load reduction from unmitigated development
Pollutant
Required Achieved
Total Suspended Solids (TSS) 80 84 (+4.0)
Total Phosphorous (TP) 60 60.0 (+0.0)
Total Nitrogen (TN) 45 54.4 (+9.4)
Gross Pollutants>5mm (GP) 90 100 (+10.0)
The proposed treatment train exceeds all the required pollutant load reductions stipulated by NSC.
Refer Appendix AB for further MUSIC modelling details.
4. 3 Con st ruc t io n Ph a se
Management of stormwater run-off during construction is necessary to avoid pollution of downstream
waterways from sediment and gross pollutant loading. Pollutants typically generated during construction
phase are described in table 9.
Table 10 – Pollutants typically generated during the construction phase
Pollutant Sources
Litter (Gross Pollutants) Paper, construction packaging, food packaging, cement bags.
Sediment Unprotected exposed soils and stockpiles during earthworks and building.
Hydrocarbons Fuel and oil spills, leaks from construction equipment.
Toxic materials Cement slurry, asphalt prime, solvents, cleaning agents, wash waters.
pH altering substances Acid sulphate soils, cement slurry and wash waters.
Refer Table A in separate SPP Appendix 2 for further stormwater management design objectives that
are applicable to all climatic regions.
4.3.1 E ro sio n and Se di men t Co ntr ol
Impacts of inadequate erosion and sediment control downstream from the site include:
1. Traffic safety problems
2. Blocked drains
3. Local flooding problems
4. Aesthetic pollution of drainage paths, and
5. Damage to local ecosystems
Best practice erosion and sediment controls must be installed to minimise the discharge of sediment
laden run-off during construction.
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Erosion and sediment control plans shall be developed during detailed design phase and must be
continually maintained and amended as required to minimise environmental harm.
Erosion and sediment control plans are based on three sets of control measures:
1. Drainage control
2. Erosion control
3. Sediment control
These control measures must be maintained in an effective operational condition. Sediment disposal
from site is to occur to the satisfaction of NSC. Defects in erosion and sediment control devices, such
as sediment fences and baskets, are to be inspected and documented. Upon Inspection, the Contractor
is to determine whether the device should be replaced or repaired. Documentation is to include how the
damage (if applicable) was caused and what measures can be implemented to reduce the possibility
of repeat occurrences. Any damage to either permanent or temporary water quality control structures
or devices is to be immediately rectified at the contractor’s expense.
The effectiveness of the erosion and sediment control devices can be monitored by visual audits. All
ESC measures are to be inspected:
at least daily (when work is occurring on site) or weekly (when work is not occurring on site)
within 24 hours of expected rain
within 18 hours of a rainfall event (i.e. an event of sufficient intensity and duration to mobilise
sediment on site)
Drainage paths are to be inspected to ensure the sediment fences are not being bypassed as a result
of soil erosion.
Sediment laden run-off shall be prevented from entering neighbouring properties. This shall be achieved
by landscaping disturbed areas immediately and prior to a rainfall event.
An erosion hazard assessment has been conducted in accordance with IECA.
The proposed development received an erosion hazard score of 23. This score exceeds the trigger
value of 17. Additionally, the proposed site meets or exceeds the trigger value for area of disturbance
and waterway disturbance due to the construction of the bridge across the existing natural channel. As
part of the detailed design phase of the proposed development a detailed ESCP shall be prepared by
a suitably qualified consultant. See Appendix AA for the completed erosion hazard assessment form.
4.3.2 M aint en an ce and M onit o ri ng R equ ir em ent s
Periodic maintenance and monitoring of stormwater devices proposed in this report is crucial to ensure
effective operation and design life.
Inspect field inlet grates, pits and underground pipes for blockage or damage at least 6 monthly or after
significant rainfall event. Bioretention basins should be inspected for scour of filter medium, death of
plants, collapse of filter medium and ponding at least 3 monthly or after significant rainfall event. Results
of the initial 12 months maintenance program shall be used to determine future maintenance intervals.
Refer manufactures maintenance and monitoring methodology for specific details.
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Table 11 – Maintenance of ESC measures
ESC Measure Maintenance Trigger Timeframe for Completion of
Maintenance
Sediment basins When settled sediment exceeds the volume Within 7 days of the inspection.
of the sediment storage zone
Other ESC measures The capacity of ESC measures falls below By the end of the day.
75%.
Sediment accumulation on ESC devices is to be removed and disposed of to the satisfaction of NSC.
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5 CO N CLU S IO N
This SWMR, with the preliminary engineering drawings, outline how stormwater run-off from the site
will be managed in order to not adversely impact the receiving environment.
The proposed relocatable home park involves the construction of 245 relocatable dwellings with a
shared clubhouse area on two currently undeveloped blocks.
The lawful points of discharge for the site have been determined to be the north, north east and south
east sides of the properties within the Cooroy golf course as detailed in Appendix AC. four bioretention
basins (One for each sub-catchment shall be constructed to mitigate developed flows to match or
reduce peak flows compared to the existing. The proposed OSD was modelled using the hydraulic
modelling program XPSTORM and has been shown to reduce peak flows for all design events ranging
from 63.2% to 1% AEP. Bioretention basin four has not been modelled for OSD purposes and is
considered to be free draining.
The proposed development triggers the requirement for stormwater quality from NSC and QLD’s state
planning policy Appendix 2. Water quality modelling was completed using MUSIC. The proposed water
quality treatment train consists of four bioretention basins (one for each catchment). The proposed
treatment train has been shown to meet the reduction targets outlined by NSC and the state planning
policy.
By implementing the proposed stormwater management system, and providing adequate maintenance,
the downstream environment and neighbouring properties will not experience any adverse deterioration
of water quality as a result of the proposed development.
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6 AP P E N D IC E S
6. 1 Ap p end ix A A – E ro s i on Haz a rd As s e ss me nt
The following erosion hazard assessment form is presented as an example. Regulatory
authorities may choose to modify its contents and/or trigger value to better address local issues
and conditions (e.g. within the catchment of sensitive receiving waters).
The total score is used to identify certain actions required by the proponent, or may simply be
used to identify low-risk and high risk sites. Within the attached form, a total score of 17 (default
value) or greater may be considered high-risk.
The trigger values are used to identify issues of particular importance and to trigger specific
actions required by the proponent, such as the submission of a preliminary ESCP during the
planning phase of the development.
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Best Practice Erosion And Sediment Control Erosion Hazard Assessment Form
Erosion Hazard Assessment Form
Condition Points Score Trigger
value
AVERAGE SLOPE OF DISTURBANCE AREA [1]
not more than 3% [3% 33H:1V] 0
more than 3% but not more than 5% [5% = 20H:1V] 1
1 4
more than 5% but not more than 10% [10% = 10H:1V] 2
more than 10% but not more than 15% [15% 6.7H:1V] 4
more than 15% 6
SOIL CLASSIFICATION GROUP (AS1726) [2]
GW, GP, GM, GC 0
SW, SP, OL, OH 1 3
SM, SC, MH, CH 2
ML, CL, or if imported fill is used, or if soils are untested 3
EMERSON (DISPERSION) CLASS NUMBER [3]
Class 4, 6, 7, or 8 0
Class 5 2 4 6
Class 3, (default value if soils are untested) 4
Class 1 or 2 6
DURATION OF SOIL DISTURBANCE [4]
not more than 1 month 0
more than 1 month but not more than 4 months 2 4 6
more than 4 months but not more than 6 months 4
more than 6 months 6
AREA OF DISTURBANCE [5]
not more than 1000 m2 0
more than 1000 m2 but not more than 5000 m2 1 4
6
more than 5000 m2 but not more than 1 ha 2
more than 1 ha but not more than 4 ha 4
more than 4 ha 6
WATERWAY DISTURBANCE [6]
No disturbance to a watercourse, open drain or channel 0
2 2
Involves disturbance to a constructed open drain or channel 1
Involves disturbance to a natural watercourse 2
REHABILITATION METHOD [7]
Percentage of area (relative to total disturbance) revegetated by seeding
without light mulching (i.e. worst-case revegetation method).
not more than 1% 0 0
more than 1% but not more than 5% 1
more than 5% but not more than 10% 2
more than 10% 4
RECEIVING WATERS [8]
Saline waters only 0 2
Freshwater body (e.g. creek or freshwater lake or river) 2
SUBSOIL EXPOSURE [9]
No subsoil exposure except of service trenches 0 0
Subsoils are likely to be exposed 2
EXTERNAL CATCHMENTS [10]
No external catchment 0
0
External catchment diverted around the soil disturbance 1
External catchment not diverted around the soil disturbance 2
ROAD CONSTRUCTION [11]
No road construction 0 0
Involves road construction works 2
pH OF SOILS TO BE REVEGETATED [12]
more than pH 5.5 but less than pH 8 0 1
other pH values, or if soils are untested 1
Total Score [13] 23 17
IECA (Australasia) November 2008 Page 1
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Explanatory notes
Requirements: Specific issues or actions required by the proponent.
Warnings: Issues that should be considered by the proponent.
Comments: General information relating to the topic.
[1] REQUIREMENTS:
For sites with an average slope of proposed land disturbance greater than 10%, a
preliminary ESCP must be submitted to the regulatory authority for approval
during planning negotiations.
Proponents must demonstrate that adequate erosion and sediment control
measures can be implemented on-site to effectively protect downstream
environmental values.
If site or financial constraints suggest that it is not reasonable or practicable for
the prescribed water quality objectives to be achieved for the proposal, then the
proponent must demonstrate that alternative designs or construction techniques
(e.g. pole homes, suspended slab) cannot reasonably be implemented on the
site.
WARNINGS:
Steep sites usually require more stringent drainage and erosion controls than
flatter grade sites.
COMMENTS:
The steeper the land, the greater the need for adequate drainage controls to
prevent soil and mulch from being washed from the site.
[2] REQUIREMENTS:
If the actual soil K-factor is known from soil testing, then the Score shall be
determined from Table 1.
If a preliminary ESCP is required during planning negotiations, then it must be
demonstrated that adequate space is available for the construction and operation
of any major sediment traps, including the provision for any sediment basins and
their associated embankments and spillways. It must also be demonstrated that
all reasonable and practicable measures can be taken to divert the maximum
quantity of sediment-laden runoff (up to the specified design storm) to these
sediment traps throughout the construction phase and until the contributing
catchment is adequately stabilised against erosion.
WARNINGS:
The higher the point score, the greater the need to protect the soil from raindrop
impact and thus the greater the need for effective erosion control measures. A
point score of 2 or greater will require a greater emphasis to be placed on
revegetation techniques that do not expose the soil to direct rainfall contact
during vegetation establishment, e.g. turfing and Hydromulching.
COMMENTS:
Table 2 provides an indication of soil conditions likely to be associated with a
particular Soil group based on a statistical analysis of soil testing across NSW.
This table provides only an initial estimate of the likely soil conditions.
IECA (Australasia) November 2008 Page 2
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The left-hand-side of the table provides an indication of the type of sediment
basin that will be required (Type C, F or D). The right-hand-side of the table
provides an indication of the likely erodibility of the soil based on the Revised
Universal Soil Loss Equation (RUSLE) K-factor.
Table 3 provides some general comments on the erosion potential of the various
soil groups.
Table 1 – Score if soil K-factor is known
RUSLE soil erodibility K-factor
K < 0.02 0.02<K<0.04 0.04<K<0.06 K > 0.06
Score 0 1 2 3
Table 2 – Statistical analysis of NSW soil data [1]
Unified Likely sediment basin Probable soil erodibility K-factor (%) [2]
Soil classification (%)
Class Dry Wet Low Moderate High Very High
System
Type C Type F Type D K < 0.02 0.02<K<0.04 0.04<K<0.06 K > 0.06
GM 30 58 12 12 51 26 12
GC 42 33 25 13 71 17 0
SW 40 48 12 49 39 12 0
SP 53 32 15 76 18 5 1
SM 21 67 12 26 48 25 1
SC 26 50 24 16 64 18 2
ML 5 63 32 4 35 45 16
CL 9 51 39 12 56 19 13
OL 2 80 18 34 61 5 1
MH 12 41 48 15 19 41 25
CH 5 44 51 39 43 11 7
Notes: [1] Analysis of soil data presented in Landcom (2004).
[2] Soil erodibility based on Revised Universal Soil Loss Equation (RUSLE) K-factor.
Unified Soil Classification System (USCS)
GW Well graded gravels, gravel-sand mixtures, little or no fines
GP Poorly graded gravels, gravel-sand mixture, little or no fines
GM Silty gravels, poorly graded gravel-sand-silt mixtures
GC Clayey gravels, poorly graded gravel-sand-clay mixtures
SW Well graded sands, gravelly sands, little or no fines
SP Poorly graded sands, gravelly sands, little or no fines
SM Silty sands, poorly graded sand-silt mixtures
SC Clayey sands, poorly graded sand-clay mixtures
ML Inorganic silts & very fine sands, rock flour, silty or clayey fine sands with slight plasticity
CL Inorganic clays, low–medium plasticity, gravelly clays, sandy clays, silty clays, lean clays
OL Organic silts and organic silt-clays of low plasticity
MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts
CH Inorganic clays of high plasticity, fat clays
OH Organic clays of medium to high plasticity
IECA (Australasia) November 2008 Page 3
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Table 3 – Typical properties of various soil groups [1]
Soil Groups Typical properties [2]
GW, GP Low erodibility potential.
GM, GC Low to medium erodibility potential.
May create turbid runoff if disturbed as a result of the release of silt
and clay particles.
SW, SP Low to medium erodibility potential.
SM, SC Medium erodibility potential.
May create turbid runoff if disturbed as a result of the release of silt
and clay particles.
MH, CH Highly variable (low to high) erodibility potential.
Will generally create turbid runoff if disturbed.
ML, CL High erodibility potential.
Tendency to be dispersive.
May create some turbidity in runoff if disturbed.
Note: [1] After Soil Services & NSW DLWC (1998).
[2] Any soil can represent a high erosion risk if the binding clays or silts are unstable.
Table 4 provides general guidelines on the suitability of various soil groups to various
engineering applications.
Table 4 – Engineering suitability based on Unified Soil Classification [1]
Embankments
USC Fill Slope Untreated
Unified Soil Class Water Non
Group stability roads
retaining water
retaining
Well graded gravels GW Unsuitable Excellent Excellent Excellent Average
Poorly graded gravel GP Unsuitable Average Excellent Average Unsuitable
Silty gravels GM Unsuitable Average Good Average Average
Clayey gravels GC Suitable Average Good Average Excellent
Well graded sands SW Unsuitable Excellent Excellent Excellent Average
Poorly graded sands SP Unsuitable Average Good Average Unsuitable
Silty sands SM Suitable [2] Average Average Average Poor
Clayey sands SC Suitable Average Average Average Good
Inorganic silts ML Unsuitable Poor Average Poor Unsuitable
Inorganic clays CL Suitable [2] Good Average Good Poor
Organic silts OL Unsuitable Unsuitable Poor Unsuitable Unsuitable
Inorganic silts MH Unsuitable Poor Poor Poor Unsuitable
Inorganic clays CH Suitable [2] Average Unsuitable Average Unsuitable
Organic clays OH Unsuitable Unsuitable Unsuitable Unsuitable Unsuitable
Highly organic soils Pt Unsuitable Unsuitable Unsuitable Unsuitable Unsuitable
Notes: [1] Modified from Hazelton & Murphy (1992)
[2] Suitable only after modifications to soil such as compaction and/or erosion protection
IECA (Australasia) November 2008 Page 4
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[3] If the soils have not been tested for Emerson Class, then adopt a score of 4.
REQUIREMENTS:
Works proposed on sites containing Emerson Class 1 or 2 soils have a very high
pollution potential and must submit a conceptual ESCP to the regulatory authority
for review and/or approval (as required by the authority) during planning
negotiations.
WARNINGS:
Class 3 and 5 soils disturbed by cut and fill operations or construction traffic are
highly likely to discolour stormwater (i.e. cause turbid runoff). Chemical
stabilisation will likely be required if these soils are placed immediately adjacent
to a retaining wall. Any disturbed Class 1, 2, 3 and 5 soils that are to be
revegetated must be covered with a non-dispersive topsoil as soon as possible
(unless otherwise agreed by the regulatory authority).
Class 1 and 2 soils are highly likely to discolour (pollute) stormwater if exposed to
rainfall or flowing water. Treatment of these soils with gypsum (or other suitable
substance) will most likely be required. These soils should not be placed directly
behind a retaining wall unless it has been adequately treated (stabilised) or
covered with a non-dispersible soil.
[4] The duration of disturbance refers to the total duration of soil exposure to rainfall
up until a time when there is at least 70% coverage of all areas of soil.
REQUIREMENTS:
All land developments with an expected soil disturbance period greater than 6
months must submit a conceptual ESCP to the regulatory authority for review
and/or approval (as required by the authority) during planning negotiations.
COMMENTS:
Construction periods greater than 3 months will generally experience at least
some significant storm events, independent of the time of year that the
construction (soil disturbance) occurs.
[5] REQUIREMENTS:
Development proposals with an expected soil disturbance in excess of 1ha must
submit a conceptual ESCP to the regulatory authority for review and/or approval
(as required by the regulatory authority) during planning negotiations.
The area of disturbance refers to the total area of soil exposed to rainfall or dust-
producing winds either as a result of:
(a) the removal of ground cover vegetation, mulch or sealed surfaces;
(b) past land management practices;
(c) natural conditions.
WARNINGS:
A Sediment Basin will usually be required if the disturbed area exceeds 0.25ha
(2500m2) within any sub-catchment (i.e. land flowing to one outlet point).
COMMENTS:
For soil disturbances greater than 0.25ha, the revegetation phase should be
staged to minimise the duration for which soils are exposed to wind, rain and
concentrated runoff.
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[6] REQUIREMENTS:
All developments that involve earthworks or construction within a natural
watercourse (whether that watercourse is in a natural or modified condition) must
submit a conceptual ESCP to the regulatory authority for review and/or approval
(as required by the regulatory authority) during planning negotiations.
Permits and/or licences may be required from the State Government, including
possible submission of the ESCP to the relevant Government department.
[7] REQUIREMENTS:
No areas of soil disturbance shall be left exposed to rainfall or dust-producing
winds at the end of a development without an adequate degree of protection
and/or an appropriate action plan for the establishment of at least 70% cover.
COMMENTS:
Grass seeding without the application of a light mulch cover is considered the
least favourable revegetation technique. A light mulch cover is required to
protect the soil from raindrop impact, excessive temperature fluctuations, and the
loss of essential soil moisture.
[8] COMMENTS:
All receiving waters can be adversely affected by unnatural quantities of
sediment-laden runoff. Freshwater ecosystems are generally more susceptible to
ecological harm resulting from the inflow of fine or dispersible clays than saline
water bodies. The further inland a land disturbance is, the greater the potential
for the released sediment to cause environmental harm as this sediment travels
towards the coast.
For the purpose of this clause it is assumed that all sediment-laden runoff will
eventually flow into saline waters. Thus, sediment-laden discharges that flow first
into freshwater are likely to adversely affect both fresh and saline water bodies
and are therefore considered potentially more damaging to the environment.
This clause does not imply that sediment-laden runoff will not cause harm to
saline waters.
[9] COMMENTS:
This clause refers to subsoils exposed during the construction phase either as a
result of past land practices or proposed construction activities. The exposure of
subsoils resulting from the excavation of minor service trenches should not be
considered.
[10] WARNINGS:
The greater the extent of external catchment, the greater the need to divert up-
slope stormwater runoff around any soil disturbance.
COMMENTS:
The ability to separate “clean” (i.e. external catchment) stormwater runoff from
“dirty” site runoff can have a significant effect on the size, efficiency and cost of
the temporary drainage, erosion, and sediment control measures.
IECA (Australasia) November 2008 Page 6
Page 31
Best Practice Erosion And Sediment Control Erosion Hazard Assessment Form
[11] REQUIREMENTS:
Permission must be obtained from the owner of a road reserve before placing
any erosion and sediment control measures within the road reserve.
WARNINGS:
Few sediment control techniques work efficiently when placed on a road and/or
around roadside stormwater inlets. Great care must be taken if sediment control
measures are located on a public roadway, specifically:
safety issues relating to road users;
the risk of causing flooding on the road or within private property.
The construction of roads (whether temporary or permanent) will usually modify
the flow path of stormwater runoff. This can affect how “dirty” site runoff is
directed to the sediment control measures.
COMMENTS:
“On-road” sediment control devices are at best viewed as secondary or
supplementary sediment control measures. Only in special cases and/or on very
small projects (e.g. kerb and channel replacement) might these controls be
considered as the “primary” sediment control measure.
[12] WARNINGS:
Soils with a pH less than 5.5 or greater than 8 will usually require treatment in
order to achieve satisfactory revegetation. Soils with a pH of less than 5
(whether naturally acidic or in acid sulfate soil areas) may also limit the choice of
chemical flocculants (e.g. Alum) for use in the flocculation of Sediment Basins.
[13] REQUIREMENTS:
A preliminary ESCP must be submitted to the local government for approval
during the planning phase for any development that obtains a total point score of
17 or greater or when any trigger value is scored or exceeded.
IECA (Australasia) November 2008 Page 7
Page 32
6. 2 Ap p end ix AB – M USI C d et ai ls
Stormwater Management Report
S19-007 122 & 144 Myall St, Cooroy AB
Page 33
6. 3 Ap p end ix AC – E ngi n ee r ing D r aw ings
Stormwater Management Report
S19-007 122 & 144 Myall St, Cooroy AC
Page 34
LEGEND
EXISTING CATCHMENT PLAN
PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 35
LEGEND
STORMWATER MANAGEMENT PLAN
PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 36
PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 37
PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 38
EXTERNAL CATCHMENT PLAN
PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 39
PRELIMINARY
EARTHWORKS SUMMARY
EARTHWORKS
PRELIMINARY EARTHWORKS PLAN
PRELIMINARY
SUNSHINE COAST GOLD COAST SURVEYOR No. DATE REVISIONS
SHEET APPROVED DESIGNED
SHEET NUMBER
Suite 2, Norval Corporate Centre, Level 3
13 Norval Ct, Maroochydore 17 Welch St, Southport
T 0431 803 337
E [email protected]
T 07 5571 1599 F 07 5571 1330
E [email protected] PROJECT DRAWN
PARTNERS BRISBANE NORTHERN NSW USE FIGURED DIMENSIONS ONLY. DO NOT SCALE, IF A DISCREPANCY ARISES CHECK WITH THE
PROJECT ENGINEER AND/OR SUPERVISING AUTHORITY. DO NOT WORK FROM REDUCED SCALE LOCATION DATE DRAWN
REVISION
Level 2 Limestore, 11 Sailfish Way, Kingscliff
33 Longland St, Newstead T 02 6674 8047 F 02 6674 8049
DRAWINGS (A1-A3 SIZE PAPER). COPYRIGHT OF ALL DRAWINGS & WORKS EXECUTED FROM PROJECT NUMBER
THEM IS VESTED IN WESTERA PARTNERS AND USE OF THERE FORE WITHOUT PERMISSION IS
T 07 3852 4333 F 07 3852 4777 E [email protected] STRICTLY PROHIBITED! IT IS THE BUILDERS RESPONSIBILITY TO ENSURE ALL WORKS ARE
www.westerapartners.com.au ABN 52 097 417 975 E [email protected] CARRIED OUT WITH DUE CARE AND DILIGENCE TO COMPLY WITH THE CONTRACT DOCUMENTS. CLIENT For and on behalf of
WESTERA PARTNERS PTY. LTD.
FILE NAME
Page 40
Flood Study Proposed Relocatable Home Park 122 & 144 Myall St, Cooroy Lots 2 & 3 on SP115864 For: Gemlife 11 December 2019 Ref: S19-007 11 December 2019 Flood Study 1 S19-007 122 & 144 Myall St, Cooroy
Page 41
DO C UM ENT I NFO RM AT IO N
Client Contact: Gemlife
Project Name: Flood Study for
122 & 144 Myall St, Cooroy
Westera Partners Ref: S19-007
Westera Partners Contact:
Bret Arthur Phone: 07 5571 1599
Email: [email protected]
Justin Tunsted Email: [email protected]
Certified for Issue by:
Bret Arthur RPEQ 4384
11 December 2019
Document Control:
Revision Author Checked Approved for Issue Date
Revision 0 Justin Tunsted Bret Arthur Bret Arthur 16.08.2019
Revision 1 Justin Tunsted Bret Arthur Bret Arthur 11.12.2019
This report has been prepared for Gemlife for the purpose of ensuring the proposed development on
lot 43 on SP185955 does not create a detrimental effect to neighbouring properties during design
flood events up to the 1% AEP. This report must only be used by Gemlife for this purpose and must
not be used or relied upon by any other person for any other purpose.
The assessment, conclusions or recommendations in this report are based on conditions encountered
and information received at the time of preparing the report and may not be relied upon as site
conditions or operations vary over time.
Flood Study 2
S19-007 122 & 144 Myall St, Cooroy
Page 42
CO NT E NT S
1 Introduction ............................................................................................................................ 6
2 Site Description ..................................................................................................................... 6
2.1 Location and Land Use ............................................................................................................ 6
3 Hydrology ............................................................................................................................... 7
3.1 Contributing catchment parameters ........................................................................................ 7
3.1.1 Catchment area ....................................................................................................................... 7
3.1.2 Fraction impervious ................................................................................................................. 9
3.1.3 Manning’s roughness ............................................................................................................... 9
3.1.4 Initial and continuing losses ................................................................................................... 10
3.1.5 Rainfall temporal patterns ...................................................................................................... 11
3.1.6 1D Hydraulic model layout ..................................................................................................... 11
3.1.7 Determination of critical storm duration ................................................................................. 12
3.1.8 Rational method ..................................................................................................................... 13
3.1.9 2D Modelling parameters....................................................................................................... 14
3.1.10 Developed Site Drainage ....................................................................................................... 21
4 2D Modelling Results .......................................................................................................... 23
4.1 4.1 Base Case Results .......................................................................................................... 23
4.1.1 50% Aep Existing Case Results (no blockage) ..................................................................... 23
4.1.2 20% Aep Existing Results (no blockage) ............................................................................... 24
4.1.3 10% Aep Existing Results (no blockage) ............................................................................... 24
4.1.4 5% Aep Existing Results (no blockage) ................................................................................. 24
4.1.5 2% Aep Existing Results (no blockage) ................................................................................. 24
4.1.6 1% Aep Results (no blockage) .............................................................................................. 24
4.1.7 1 in 500 Year Existing Results (no blockage) ........................................................................ 25
4.1.8 1 in 2000 Year Existing Results (no blockage) ...................................................................... 25
4.1.9 PMP Existing Results (no blockage) ..................................................................................... 25
4.2 Developed Case Results ....................................................................................................... 26
4.2.1 50% Aep Results (Developed no blockage) .......................................................................... 26
4.2.2 50% Aep Results (Developed with blockage) ....................................................................... 26
4.2.3 20% Aep Results (Developed no blockage) .......................................................................... 26
4.2.4 20% Aep Results (Developed with blockage) ....................................................................... 26
4.2.5 10% Aep Results (Developed no blockage) .......................................................................... 27
4.2.6 10% Aep Results (Developed with blockage) ....................................................................... 27
4.2.7 5% Aep Results (Developed no blockage) ............................................................................ 27
4.2.8 5% Aep Results (Developed with blockage).......................................................................... 27
4.2.9 2% Aep Results (Developed no blockage) ............................................................................ 27
4.2.10 2% Aep Results (Developed with blockage).......................................................................... 28
Flood Study 3
S19-007 122 & 144 Myall St, Cooroy
Page 43
4.2.11 1% Aep Results (Developed no blockage) ............................................................................ 28
4.2.12 1% Aep Results (Developed with blockage).......................................................................... 29
4.2.13 1 in 500 Results (Developed no blockage) ............................................................................ 29
4.2.14 1 in 500 Results (Developed with blockage) ......................................................................... 30
4.2.15 1 in 2000 Results (Developed no blockage) .......................................................................... 30
4.2.16 1 in 2000 Results (Developed with blockage) ....................................................................... 30
4.2.17 PMP Results (Developed no blockage) ................................................................................. 30
4.2.18 PMP Results (Developed with blockage) .............................................................................. 30
4.3 Afflux Results and Discussion ............................................................................................... 30
4.3.1 50% Aep Afflux (no blockage) ............................................................................................... 31
4.3.2 50% Aep Afflux (with blockage) ............................................................................................. 31
4.3.3 20% Aep Afflux (no blockage) ............................................................................................... 31
4.3.4 20% Aep Afflux (with blockage) ............................................................................................. 31
4.3.5 10% Aep Afflux (no blockage) ............................................................................................... 31
4.3.6 10% Aep Afflux (with blockage) ............................................................................................. 31
4.3.7 5% Aep Afflux (no blockage) ................................................................................................. 31
4.3.8 5% Aep Afflux (with blockage) ............................................................................................... 32
4.3.9 2% Aep Afflux (no blockage) ................................................................................................. 32
4.3.10 2% Aep Afflux (with blockage) ............................................................................................... 32
4.3.11 1% Aep Afflux (no blockage) ................................................................................................. 33
4.3.12 1% Aep Afflux (with blockage) ............................................................................................... 34
5 Conclusion ........................................................................................................................... 35
6 Appendices ..............................................................................................................................
6.1 Appendix BA – Catchment Layout ........................................................................................ BA
6.2 Appendix BB – Reporting points and flow line locations ...................................................... BB
6.3 Appendix BC – Flood Maps and Afflux Maps ....................................................................... BC
6.4 Appendix BD – ARR DataHub Data ..................................................................................... BD
6.5 Appendix BE – Adopted Bridge Cross Sections ................................................................... BE
6.1 Appendix BF – 1D Blockage Locations ................................................................................ BF
FIG U R E S
Figure 1 – Indicative Site location and property boundary (NearMap 2019) ................................ 7
Figure 2 – External catchment extents (image from nearmap 2019) ........................................... 8
Figure 3 – 1D model layout (Image from NearMap 2019) .......................................................... 12
Figure 4 – 2D model grid extents ............................................................................................... 16
Figure 5 – 2D Flow Lines ............................................................................................................ 17
Flood Study 4
S19-007 122 & 144 Myall St, Cooroy
Page 44
Figure 6 – 2D Flow Lines ............................................................................................................ 18
Figure 7 – Head/Velocity Locations ............................................................................................ 20
Figure 8 – Developed Catchment Breakdown............................................................................ 23
Figure 9 – 1% AEP existing flood depths extract. ...................................................................... 25
Figure 10 – 1% AEP Developed flood depths extract. ............................................................... 29
Figure 11 – Proposed Bridge Cross section (taken as the natural channel cross section for the
span of the bridge taken up to the underside of the bridge structure) .................................. 1
Figure 12 – Existing Rail Bridge (Item 2 in table 6 of above report) ............................................. 2
Figure 13 – Existing Miva St Crossing (Item 6 in table 6 of above report) ................................... 2
T AB LE S
Table 1 – Existing catchment details (refer figure 2 and Appendix BA) ....................................... 9
Table 2 – 2D Landuses ............................................................................................................... 10
Table 3 –Critical 1D peak flow rates and critical storms (XPStorm) ........................................... 13
Table 4 – Time of concentration summary ................................................................................. 14
Table 5 – Blockage factor risk assessment ................................................................................ 19
Table 6 – Blockage percentage (design AEP) for existing and proposed 1D elements ............. 19
Table 7 – Developed catchment details (refer figure 8 and Appendix BA) ................................. 22
Flood Study 5
S19-007 122 & 144 Myall St, Cooroy
Page 45
1 INT RO D UCT IO N
Westera Partners Pty Ltd has been commissioned by Gemlife to prepare a Flood Study for the proposed
relocatable home park to be constructed on Lots 2 & 3 on SP115864 (the development site).
The proposed development site is impacted by a large external catchment with flows passing under the
Bruce Highway from the south west towards Myall St then continuing north through the existing channel
located within the development site on the Cooroy golf course.
The existing site is significantly higher than the bed level of the existing channel with an approximate
level at the property boundary of approximately 110m AHD with the adjacent bed level at approximately
104m AHD (determined using LIDAR information).
The development proposes to have access to the site via an access road off of Myall St. This road shall
cross the existing channel. This report shall detail the hydrology and hydraulics of the external
catchments draining through the channel adjacent to the development as well as the any other external
catchments downstream to determine the extent of flooding in the existing case. A proposed solution
(at the proposed crossing adjacent to the development) will then be modelled with the goal of ensuring
no afflux to adjacent properties or the development with impact to the existing channel to be minimised.
The development site falls within the local government area of “Noosa Shire Council” (NSC).
The proposed solution for crossing the existing channel determined at the preliminary stage is a double
span bridge.
The purpose of this report shall be to show that the proposed solution will not cause any nuisance to
adjacent properties or the development site.
2 SIT E D ES CR I PT IO N
2. 1 Loc at i on an d L an d U se
The site of the proposed development is located on Lots 2 & 3 on SP115864. The proposed
development area is approximately 97,390m2. The existing site is zoned by NSC as ‘Rural, Open Space,
Recreation’. At the time of writing this report, the site is considered undeveloped.
The site is bound by Cooroy golf course to the north, east and south. Myall Street borders the western
boundary. An existing railway line is located downstream of the development. This could act as a flow
constriction during large flood events. Refer Figure 1 & Appendix G for further information.
Flood Study 6
S19-007 122 & 144 Myall St, Cooroy
Page 46
Figure 1 – Indicative Site location and property boundary (NearMap 2019)
3 HY DR O LO G Y
The hydrologic assessment of the existing site and external catchments has been conducted in
accordance with ARR2016 and QUDM 2017. The software packages that has been used to model the
external catchment are XPStorm version 2018.1 and CatchmentSim. This section of the report will detail
the methodology used to determine the critical storm or storms for the design events ranging from 50%
to 1% “Annual Exceedance Probability” (AEP).
The XPStorm 1D/2D modelling program, utilising the “Laurenson” runoff routing method, has been used
to model the catchment characteristics to determine the peak stormwater flow discharging from all
external catchments during each design storm event for durations ranging from 30 minutes up to 24
hours.
3. 1 Cont ri but i ng c at chm ent pa r am et er s
3.1.1 Cat ch me nt a re a
The external catchments upstream of the development site have been determined using LIDAR (1m2
LIDAR dated 2015) sourced from the “Queensland government department of natural resources, mines
and energy” (QDNR). CatchmentSim has been used to determine external catchment areas. The
external catchments have been broken up based on areas of uniform slope. Figure 2 below (and
Appendix BA) depicts the catchments that were determined using this methodology.
The total area of the external catchments contributing to the downstream discharge point is
approximately 387 hectares. The external catchment has a low percentage impervious as the majority
is rural or undeveloped.
Flood Study 7
S19-007 122 & 144 Myall St, Cooroy
Page 47
Figure 2 – External catchment extents (image from nearmap 2019)
The following table details the external catchment characteristics.
Flood Study 8
S19-007 122 & 144 Myall St, Cooroy
Page 48
Table 1 – Existing catchment details (refer figure 2 and Appendix BA)
Catchment 1.01 1.02 1.03 1.04 1.05 1.06
Area (ha) 158.33 39.95 14.38 10.32 5.13 13.53
% impervious
10% 10% 10% 5% 5% 5%
Catchment
8.63 4.36 1.90 4.07 5.50 3.90
Slope (%)
Catchment 1.07 1.08 2.01 3.01 3.02 3.03
Area 4.13 14.148 0.61 50.35 32.70 8.36
% impervious
5% 5% 5% 10% 35% 5%
Catchment
5.71 6.48 2.68 5.95 4.20 4.95
Slope (%)
Catchment 4.01 5.01 5.02
Area 12.46 21.19 1.39
% impervious
60% 5% 5%
Catchment
3.64 3.29 8.06
Slope (%)
3.1.2 Fr act ion i mp e rv iou s
The external catchments has been classified as rural residential. QUDM (2017) specifies in table 4.5.1
that rural residential developments shall range between 10 – 20% impervious. The lower bound of this
range has been adopted. Catchments 3.02 and 4.01 have been determined to be more developed than
other parts of the catchment from aerial imagery. Catchment 4.01 is considered to be urban residential
– low density (including roads). Table 4.5.1 gives a range from 45% - 85% for this landuse. Catchment
3.02 is also considered to be urban residential – with roads, however due to the large open space area
the overall fraction impervious has been reduced.
3.1.3 M anning’ s r ough ne s s
The external catchments are largely undeveloped and well grassed. In addition catchments 1.01
through 1.04 have sections of dense vegetation surrounding the banks of the existing creek. Therefore
within the runoff model for pervious areas a Mannings roughness of 0.045 has been adopted for all
catchments. These values have been adopted based on Appendix C of ‘Brisbane City Council’s’ (BCC)
Natural Channel Design Guidelines (2003).
Flood Study 9
S19-007 122 & 144 Myall St, Cooroy
Page 49
For impervious areas a Mannings roughness of 0.014 has been adopted for all catchments as these
areas are likely to be concrete, asphalt and roof areas.
The adopted Mannings coefficients used in the runoff layer have been summarised below.
Pervious Area n = 0.045
Impervious Area n = 0.014
The roughness in the 1D links (shown below) have been based on a meandering channel with an
irregular cross section (pg. 148, BCC, 2003). This value has been used for both the channel and the
overbank area. Manning’s roughness used for the 2D modelling will be detailed in table 2 below.
1D Links n = 0.045
2D Landuse Mannings Roughness
The external catchments consist of a combination of paved surfaces, pasture areas with short to
medium height grasses (including sports field areas) and areas with thick vegetation. To reflect this
various Mannings roughness values have been adopted. The adopted values for each landuse is
present in the below table.
Table 2 – 2D Landuses
Landuse Mannings (n) value
Creek 0.045
Grass 0.045
Road 0.02
Trees (Heavily
0.1
Vegetated)
3.1.4 Init i al an d cont inu ing lo s se s
The values for initial and continuing losses for pervious areas as provided by ARRDatahub ((for
coordinates -26.445, 152.897) sourced on the 30 March, 2019) are shown below.
Pervious Area
Initial Loss 32mm
Continuing Loss 2.6mm/hr
Flood Study 10
S19-007 122 & 144 Myall St, Cooroy
Page 50
The initial loss for pervious areas is considered to be high as preburst depths are not proposed.
Therefore the initial loss has been reduced to compensate for the absence of prebursts. Please see
below adopted initial and continuing losses below.
Pervious Area
Initial Loss 15mm
Continuing Loss 2.6mm/hr
Impervious Areas
Initial Loss 0mm
Continuing Loss 0mm/hr
Preburst depths
Prebursts have not been adopted for any of the models mentioned in this report.
3.1.5 Ra inf al l t em po ra l pat t e rns
XPStorm has incorporated the temporal patterns from ARR DataHub for the given site location (-26.445,
152.897) sourced on the 30 March, 2019 within the east coast north region.
These temporal patterns have been used to determine the critical storm duration for each of the design
events.
Areal reduction factors have been incorporated into the model as required, which were sourced from
ARRdatahub for the above mentioned coordinates and date.
3.1.6 1D H yd r aul ic m od el l a yout
In order to approximate the natural flow of the external catchments a 1D link and node model has been
constructed. 1D links have been run along the alignment of the creek beds within each catchment from
the top to the bottom of the model study area (depicted in figure 3). 1D runoff nodes representing the
hydrology of each sub-catchment have been placed at the ends of each reach of the creek with the
hydrologic parameters as shown in table 1. To ensure that the 1D accurately reflects reality each 1D
link has been set with the cross section of each catchments midpoint. The 1D model extends to the
beginning of the 2D model bounds. The layout of the 1D is shown in figure 3 below.
Flood Study 11
S19-007 122 & 144 Myall St, Cooroy
Page 51
Figure 3 – 1D model layout (Image from NearMap 2019)
The critical points for this model have been considered to be links 59 and 41 (see figure 2). Link 59 has
been chosen as it represents a critical point upstream of the development. Link 41 was chosen as it will
be the downstream end of the model and therefore represent the downstream condition.
3.1.7 Det e rm in at io n of cr it i ca l st o r m d ur at ion
Initially storm durations 30 minutes to 24 hours for the 50% to 1% AEP were run in the 1D model with
both runoff and hydraulic modes active with the 2D inactive. Later the 1 in 500, 1 in 2000 and PMP
events were run as a method of checking the model sensitivity.
The ensemble statistics utility within XPStorm was used to find the median storm at each of the above
selected critical links. The median storm was chosen in accordance with ARR 2016 guidelines. Table
2 shows the peak flows and critical storm for each of the design events at the above mentioned critical
locations.
The critical storms shown in table 2 range from 3 hours to 45 minutes.
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Table 3 – Critical 1D peak flow rates and critical storms (XPStorm)
Peak Flow Rate (m3/s)
AEP Storm Event
Link 59 Link 41
50% 19.680 26.342
Critical Storm 3hr_5 3hr_9
20% 27.492 35.661
Critical Storm 3hr_5 3hr_2
10% 34.415 39.636
Critical Storm 45min_1 3hr_4
5% 38.718 45.781
Critical Storm 1hr_6 3hr_4
2% 43.765 51.586
Critical Storm 1hr_5 1.5hr_2
1% 44.929 56.020
Critical Storm 45min_6 2hr_7
1 in 500 51.739 64.974
Critical Storm 1.5hr_9 2hr_1
1 in 2000 56.894 78.592
Critical Storm 1.5hr_5 3hr_9
PMP 105.000 214.520
Critical Storm 2hr_8 2hr_2
3.1.8 Rat ion al m et h od
The rational method was used as a check against ‘Laurensons’ method to validate the 1D model’s peak
flow results. The Bransby-Williams method and Figures 4.5.4.6 were used to determine the time of
concentration. The table below summarises the time of concentrations for each method.
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Table 4 – Time of concentration summary
Time of Concentration Adopted Parameters
Method Used
(Minutes)
Figure 4.5
L = 4640m; Fall = 49m, delta = varies between 2 and 3
t= 145 minutes
Figures 4.5/4.6 QUDM 2017 153
Figure 4.6
L = 50m, n = 0.035
S = 18%, t= 8.0 minutes
Bransby-Williams (Equ 4.9 L = 4.6km; A = 386.98Ha
166
QUDM 2017) Se = 0.562%
The lengths of each catchment used were taken as the longest flow path from the top of the external
catchment to the discharge point at the end of the study area. The lengths and the slopes of the bed
were determined from LIDAR information.
Equal area slope was determined using a longitudinal section of the creek bed.
Using the above times of concentration the rational method was used to calculate an estimate of peak
flow.
Below is a list of the parameters that were used to determine the peak flow of the external catchments
based on the time of concentrations detailed above.
C10 combined = 0.74
I100 2.55hrs = 61.8mm/hr
I100 2.77hrs = 59.2mm/hr
The above parameters have been used to calculate the below peak catchment flows.
1% AEP Peak flow2.55 hours = (1.2 x 0.74 x 0.0618m/hr x 3,869,800m2)/3600 = 58.99m3/s
1% AEP Peak flow2.77 hours = (1.2 x 0.74 x 0.0592m/hr x 3,869,800m 2)/3600 = 56.51m 3/s
The 1% peak flows calculated using the rational method are approximately 0.8% (2.77 hour tc) and
5.3% (2.55 hour tc) greater than the 1% peak flow as determined using the Laurenson’s method. This
difference has been attributed to the runoff routing within Laurensons method combined with the
detention in the 1D channels which the rational method does not consider.
3.1.9 2D M odel lin g p a ra m e t e rs
The external catchment and development site flows have been modelled in 2D to determine the existing
flow conditions, peak water levels, maximum flow velocities and extent of flow widths adjacent to the
development site.
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A number of 1D and 2D items have been used to model the existing catchment. The below sections list
the 2D parameters that have been adopted.
1D Nodes
1D nodes have been used to model each of the individual sub catchments. Each node is defined by its
hydrologic and hydraulic parameters. Catchment nodes did not have hydraulic parameters as their
runoff hydrographs were linked to rainfall/flow areas which distributed the runoff hydrographs evenly
over a flow area. The exception to this was the 1D nodes connecting to the 1D channels. These nodes
had invert levels equal to the channel bed.
1D nodes were also used to connect 1d elements such as headwalls to the 2D mesh.
2D Grid
The 2D grid extents were extended both upstream and downstream of the development site. A 2m grid
cell size has been adopted. A 2D time step of 0.5 seconds was adopted for all models. The following
figure depicts the extent of the 2D grid extents.
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Figure 4 – 2D model grid extents
2D Head Boundary
A single 2D head boundary was placed downstream of the development site along the boundary of the
2D mesh with a tail water level set at 0.0mAHD in order to simulate free outfall condition.
Default 2D Landuse
The default landuse that has been adopted was named “Grass”. This landuse had the below
parameters.
Mannings Roughness n = 0.045
No rainfall infiltration.
DTM
The adopted DTM used LIDAR as previously mentioned for the entire study area. The 3D survey was
overlaid on top of the LIDAR within the civil design program 12D. The LIDAR within the boundaries of
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the detailed survey was then trimmed out and a new supertin of the two combined was created. This is
the case for both the existing and developed cases as no finished surface tin is available for the
developed case.
Initial Water Level
No initial water level has been set in the 2D domain.
Flow Lines/Head and Velocity points
Flow lines were used at key locations throughout the 2D model in order to extract peak flow
hydrographs. Figures 5 and 6 depict the locations that the flow lines have placed at (Also refer Appendix
BB).
Figure 5 – 2D Flow Lines
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Figure 6 – 2D Flow Lines
1D Blockage
1D blockage levels have been determined in accordance with ARR 2016 revision project 11.
Blockage factors have been applied to specific 1D elements to determine the effect on flooding. A risk
analysis has been conducted for critical elements to determine the likely level of blockage for each
scenario.
This guideline relies on the determination of the likely debris size as well as the potential for debris to
reach the structure in question. It is preferred that evidence of debris from previous storms be used for
this analysis, however there was no evidence available at the time of this report. Additionally, the nature
of debris in large events can vary greatly from event to event as the time between events can affect the
amount of available debris.
Without data from site for this analysis the determination of the likely size of debris has been based on
aerial imagery and site visits.
Table 5 and 6 below summarises the risk assessment that has been carried out in accordance with
AR&R project 11 for each 1D element of interest. Please see Appendix BF for the locations of each
element.
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Table 5 – Blockage factor risk assessment
Category (High, Medium, Low)
1 2 3 4 5 6
Risk Factor
2 x (1800
Proposed Rail Miva St Road 2 x (2.4 x 3.0 450 diameter
diameter
Bridge Bridge Crossing RCBC) RCP
RCP)
Debris
High Medium Medium High High Low
Availability
Debris Mobility High Medium Medium Medium High Low
Debris
Low Medium High High Low Low
Transportability
Debris Potential Medium Medium Medium High Medium Low
Inlet Clear W>3x W>3x W ≥ L10 ≤ 3 x
W ≤ L10 W > 3 x L10 W ≥ L10 ≤ 3 x L10
Width (W) L10 L10 L10
Table 6 details the percentage blockage to be applied to the model for each design event.
Table 6 – Blockage percentage (design AEP) for existing and proposed 1D elements
Risk Factor Category (High, Medium, Low)
Item Number 1 2 3 4 5 6
2 x (1800 450
Proposed Rail Miva St Road
Description diameter 2 x (2.4 x 3.0 RCBC) diameter
Bridge Bridge Crossing
RCP) RCP
≥ 5% AEP 0% 0% 0% 50% 0% 0%
> 1.0% <
0% 0% 0% 50% 0% 0%
5% AEP
≤ 1.0% AEP 10% 10% 10% 100% 10% 10%
The blockage factors have been applied by reducing the area of each link by the desired blockage factor
using the XP function for the number of barrels in each link.
As a sensitivity the 1% AEP event has been run with the blockage of items 3, 4 and 5 at 100%. This will
show the worst case scenario for the maximum design event (the 1 in 500 year, 1 in 2000 year and
PMP are not considered to be design events).
1D/2D Interface
1D/2D interfaces were modelled using interface lines which were connected to 1D elements which in
the case of this project were either pipes/culverts or bridge structures. The interface lines were created
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with a length that was set to match the effective width that the 1D structure would have in reality. This
was done counting the number of cells as each cell was a length of 1m.
Rainfall/Flow areas
Rainfall/flow areas were used to connect the runoff hydrograph of individual runoff nodes to the 2D
mesh. Each flow area was set to fill the area from the lowest point first and were placed across what
was deemed to be the concentrated flow path of each sub catchment.
Head/Velocity Point Locations
Water level and Velocity results have been extracted from the models using the head/velocity point
function within XPStorm. The locations of the points are the same through all models to ensure an
accurate comparison between models. The location of these points are shown in figure 7 below (and
Appendix BB).
Figure 7 – Head/Velocity Locations
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2D Fill Areas
2D fill areas have been used to modify (either lift or lower) certain areas of the 2D mesh to reflect their
levels. An example of this is the development site which was lifted to reflect approximately the finished
surface level of the site.
Elevation Shapes
Similar to fill areas above elevation shapes are used to modify the 2D mesh levels from the underlying
DTM. This model has utilised elevation shapes to model the affect that the proposed creek crossing
would have (for instance the abutments of a bridge) on the flow widths and filling in the existing
floodplain. Elevation shapes vary from fill areas where each individual vertex of the polygon can be set
to a different elevation, where a fill area polygon is limited to a single elevation per polygon.
3.1.10 D ev e lop ed S it e Dr a i nag e
The proposed development consists of two hundred and forty five lots with associated hardstand and a
large central clubhouse. The proposed road access over the existing natural channel shall be designed
to limit the changes to the existing water course to ensure that the access does not cause increases to
the peak water level during the design flood events.
The developed catchments hydrology has been modified to reflect the increase in impervious
percentage of the development and catchment areas directed to each location. The proposed
development area to discharge downstream of the development (through proposed basins 1 and 2)
including the associated stormwater detention has been incorporated for all design storms up to the 1%
AEP event. The developed catchment discharges through a combination of a low level orifice and
overflow weir the location of which reflects the proposed stormwater management solution (see
separate SWMR by Westera Partners). All catchments that have been modified from the existing case
are highlighted in table 7 below. Catchment 1.05 has been split into catchments 1.05a and 1.05b as a
part of the development catchment will directed to the proposed bioretention basin (1.05a) and a portion
will discharge directly to the proposed golf course (1.05b). Basin 1 discharges catchment 1.05a while
basin 2 discharges the developed portion of catchment 5.01.
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Table 7 – Developed catchment details (refer figure 8 and Appendix BA)
Catchment 1.01 1.02 1.03 1.04 1.05a 1.05b
Area (ha) 158.33 39.95 14.38 9.42 5.70 1.40
% impervious
10% 10% 10% 5% 87% 25%
Catchment
8.63 4.36 1.90 4.07 5.50 5.50
Slope (%)
Catchment 1.06 1.07 1.08 2.01 3.01 3.02
Area 13.53 4.13 14.148 0.61 50.35 32.70
% impervious
5% 5% 5% 5% 10% 35%
Catchment
3.90 5.71 6.48 2.68 5.95 4.20
Slope (%)
Catchment 3.03 4.01 5.01 5.02
Area 8.36 12.46 21.36 1.39
% impervious
5% 60% 12% 5%
Catchment
4.95 3.64 3.29 8.06
Slope (%)
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[OCR of page images]
VE
é WESTERA
WU ARTNER:
Table 7 — Developed catchment details (refer figure 8 and Appendix BA)
Catchment 1.01 1.02 1.03 1.04 1.05a 1.05b
Area (ha) 158.33 39.95 14.38 9.42 5.70 1.40
% impervious
10% 10% 10% 5% 87% 25%
Catchment 8.63 4.36 1.90 4.07 5.50 5.50
Slope (%)
Catchment 1.06 1.07 1.08 2.01 3.01 3.02
Area 13.53 4.13 14.148 0.61 50.35 32.70
% impervious
5% 5% 5% 5% 10% 35%
Catchment 3.90 571 6.48 2.68 5.95 4.20
Slope (%)
Catchment 3.03 4.01 5.01 5.02
Area 8.36 12.46 21.36 1.39
% impervious
5% 60% 12% 5%
Catchment 4.95 3.64 3.29 8.06
Slope (%)
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Figure 8 – Developed Catchment Breakdown
4 2D M O DEL LI NG R E S ULT S
2D modelling of the existing case has been conducted in accordance with ARR 2016 using the
information detailed previously in this report.
The following section of this report with detail the results of the 1D/2D flood modelling using XPSTORM
version 2018.1. The key results that will be reported will be the peak water level and peak flow at key
locations which are depicted in figure 7 and 5 above.
Each design event will be presented both with and without blockage factors as defined in the previous
section.
The maximum design event that the bridge will be designed to is the 1% AEP event. The 1 in 500, 1 in
2000 and PMP events are presented as a sensitivity. Afflux will be presented for all design events up
to and including the 1% AEP.
The existing and developed flood immunity of Myall St and the rail corridor north of the site will be
commented on.
4. 1 4. 1 B as e C as e R esu lt s
The base or existing case has been modelled with a 2m 2 grid size with a 2d hydraulic timestep of 0.5
seconds. The results for the existing models are presented below.
4.1.1 50 % Ae p E xi st ing C a se R e sul ts (no b loc k ag e)
The maximum water level at reporting point 1 as extracted from the model was 105.85m AHD. The
surface level at this location is 103.83m AHD showing that the maximum depth of flow at this location
is approximately 2.02m.
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The maximum water level at Reporting point 2 was 104.34m AHD. The natural surface level at this
location is 101.81m AHD from available LIDAR information. The maximum flow depth at this location is
2.53m.
The peak flow downstream of the development site as extracted from flow line 10 was 19.37m3/s (see
figure 5 above for the location).
Myall St does not have flood immunity in the 50% AEP event.
The existing rail corridor has immunity in the above event Please refer to appendix BC for details.
4.1.2 20 % Ae p E xi st ing R e sul t s (no b loc k ag e)
The peak water level during the above event at reporting point 1 was 106.12m AHD. The peak water
level at point 2 is 104.65m AHD.
The peak flow at flow line 10 was 28.18m3/s.
The existing rail corridor has immunity in the above event.
4.1.3 10 % Ae p E xi st ing R e sul t s (no b loc k ag e)
The peak water level during the above event at reporting point 1 was 106.20m AHD. The peak water
level at point 2 is 104.84m AHD.
The peak flow at flow line 10 was 31.15m3/s.
The existing rail corridor has immunity in the above event.
4.1.4 5 % Ae p E x ist ing R e s ult s ( n o b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.33m AHD. The peak water
level at point 2 is 104.98m AHD.
The peak flow at flow line 10 was 37.05m3/s.
The existing rail corridor has immunity in the above event.
4.1.5 2 % Ae p E x ist ing R e s ult s ( n o b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.47m AHD. The peak water
level at point 2 is 105.15m AHD.
The peak flow at flow line 10 was 45.21m3/s.
The existing rail corridor has immunity in the above event.
4.1.6 1 % Ae p Re su lt s ( no blo ck ag e)
The peak water level during the above event at reporting point 1 was 106.52m AHD. The peak water
level at point 2 is 105.21m AHD.
The 1% AEP maximum flood depths are depicted below in figure 9. A complete set of flood maps for
all events is presented in Appendix BC.
The peak flow at flow line 10 was 46.86m3/s.
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The existing rail corridor has immunity in the above event.
Figure 9 – 1% AEP existing flood depths extract.
4.1.7 1 in 50 0 Y e ar E xi st i n g R e sult s (no bl oc k a ge)
The peak water level during the above event at reporting point 1 was 106.65m AHD. The peak water
level at point 2 is 105.43m AHD.
The peak flow at flow line 10 was 54.48m 3/s.
4.1.8 1 in 20 0 0 Y ea r Ex ist i ng Re su lts (no b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.73m AHD. The peak water
level at point 2 is 105.65m AHD.
The peak flow at flow line 10 was 59.32m 3/s.
4.1.9 PM P Ex ist ing R e su lt s ( no blo c ka ge)
The peak water level during the above event at reporting point 1 was 107.64m AHD. The peak water
level at point 2 is 106.69m AHD.
The peak flow at flow line 10 was 191.12m 3/s.
The 1 in 500 year, 1 in 2000 year and PMP events are provided as a method of determining the possible
extent of flooding in extreme cases and is not intended as a design event.
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4. 2 Dev elo ped C a se R e s ult s
The developed model results detailed below show the maximum water level at the key locations shown
in figure 7 above. The developed models differ from the existing case through the following ways.
Filling of development footprint to approximate finished surface levels
Modification of proposed access servicing development and proposed bridge to match
proposed finished surface levels
Modification of hydrology to match increase in impervious area and discharge location (through
proposed stormwater detention system detailed in separate stormwater management report).
Stormwater detention proposed in the separate SWMR has been incorporated into developed
cases for events 50% - 1% AEP.
Modification of extents of Manning’s Roughness areas due to clearing of vegetation for
construction of proposed bridge
The peak flows downstream of the development site have been extracted from flow line 10 to show the
effect of the proposed bridge on the existing flow conditions (see figure 5 above for the location of flow
line 10).
The developed catchment characteristics are detailed in table 7 above.
4.2.1 50 % Ae p Re su lt s ( De v elop ed no b loc k ag e)
The peak water level during the above event at reporting point 1 was 105.82m AHD. The peak water
level at point 2 is 104.31m AHD. The above peak water elevations are approximately 0.03m lower than
the peak water elevation during the existing case. This shows that the proposed bridge structure and
development does not create any additional nuisance during this event.
The peak flow at flow line 10 was 18.41m3/s. This shows a decrease of 0.96m3/s compared to the
existing case.
4.2.2 50 % Ae p Re su lt s ( De v elop ed w ith blo c ka g e)
The peak water level during the above event at reporting point 1 was 105.82m AHD. The peak water
level at point 2 is 104.46m AHD. The above peak water levels show no increase at point compared to
the developed case without blockage. Point 2 shows an increase of 0.15m compared to the developed
case without blockage.
The peak flow at flow line 10 was 18.41m3/s as per the above case without blockage.
4.2.3 20 % Ae p Re su lt s ( De v elop ed no b loc k ag e)
The peak water level during the above event at reporting point 1 was 106.09m AHD. The peak water
level at point 2 is 104.62m AHD. The peak water elevation for the developed case at point 1 is 0.03m
lower than the existing case. Point 2 shows a decrease of 0.02m compared to the existing case.
The peak flow at flow line 10 was 26.80m3/s. This is 1.38m3/s less than the existing case.
4.2.4 20 % Ae p Re su lt s ( De v elop ed w ith blo c ka g e)
The peak water level during the above event at reporting point 1 was 106.13m AHD. The peak water
level at point 2 is 104.75m AHD. The peak water elevation has increased at each point compared to
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the above developed case without blockage. The peak water elevation at point 1 has increased by
0.04m. The peak water elevation at point 2 has increased by 0.13m.
The peak flow at flow line 10 was 28.48m3/s.
The peak flow shows an increase of 0.30m3/s compared to the existing case.
4.2.5 10 % Ae p Re su lt s ( De v elop ed no b loc k ag e)
The peak water level during the above event at reporting point 1 was 106.05m AHD. The peak water
level at point 2 is 104.58m AHD. Point 1 shows a decrease in peak water elevation of 0.15m. Point 2
results in a decrease of 0.26m.
The peak flow at flow line 10 is 25.60m3/s.
The peak flow at this point has been reduced by 5.55m3/s.
4.2.6 10 % Ae p Re su lt s ( De v elop ed w ith blo c ka g e)
The peak water level during the above event at reporting point 1 was 106.20m AHD. The peak water
level at point 2 is 104.90m AHD. The peak water elevation at point 1 shows an increase in peak water
elevation of 0.03m. There is an increase in peak water elevation at point 2 of 0.08m.
The peak flow at flow line 10 was 30.93m3/s.
This shows a decrease in peak flow of 0.22m3/s compared to the existing case.
4.2.7 5 % Ae p R es ult s ( D ev el o pe d n o b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.30m AHD. The peak water
level at point 2 is 104.87m AHD. The peak water elevation at point 1 has shown a decrease of 0.03m.
There has also been an increase of 0.11m in peak water elevation at point 2. These results are in
comparison to the existing case.
The peak flow at flow line 10 was 35.13m3/s.
This shows a reduction in peak flow at this location of 1.92m3/s.
4.2.8 5 % Ae p R es ult s ( D ev elo pe d w ith bl oc k ag e )
The peak water level during the above event at reporting point 1 was 106.32m AHD. The peak water
level at point 2 is 105.04m AHD. The peak water elevation at point 1 has decreased by 0.01m
(compared to the developed case without blockage) due to the specified blockage. Peak water elevation
at point 2 has increased by 0.06m.
The peak flow at flow line 10 was 35.98m3/s which is 1.07m 3/s.
4.2.9 2 % Ae p R es ult s ( D ev elo pe d n o b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.44m AHD. The peak water
level at point 2 is 105.09m AHD. The peak water elevation at points 1 and 2 have shown no change
compared to the existing case.
The peak flow at flow line 10 was 41.28m3/s.
This shows a reduction in peak flow at this location of 3.93m3/s. The above results show decreases in
peak water level of 0.03m and 0.06m for points 1 and 2 respectively. This shows that the bridge is not
restricting flow in such a way as to cause a worsening.
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Flows approaching the development site from the south-west (Myall St and the Bruce highway) begin
to overtop the proposed intersection of Myall St and the proposed bridge during this event. The
maximum depth of flow across the intersection is approximately 0.05m.
4.2.10 2 % Ae p Re su lt s ( D ev elo pe d w ith bl oc k ag e )
The peak water level during the above event at reporting point 1 was 106.44m AHD. The peak water
level at point 2 is 105.14m AHD. The results at points 1 and 2 show a decrease of 0.03m at point 1 and
0.01m at point 2.
The peak flow at flow line 10 was 41.28m3/s.
The above peak flow is as per the above case without blockage.
4.2.11 1 % Ae p Re su lt s ( D ev elo pe d n o b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.52m AHD. The peak water
level at point 2 is 105.18m AHD. Point 1 shows no change in peak water elevation. Point 2 shows a
decrease in peak water elevation of 0.03m.
The peak flow at flow line 10 was 44.13m3/s.
This is 2.73m3/s less than the existing case. The above peak water elevation results indicate that the
bridge is not creating a worsening upstream.
Flows approaching the site from the south-west overtop the intersection of Myall St and the proposed
entry way to the development site. The maximum depth of flow across this intersection is approximately
0.05m.
The developed 1% AEP model peak water depth is presented in figure 9 below. See Appendix BC for
all design flood maps.
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Figure 10 – 1% AEP Developed flood depths extract.
4.2.12 1 % Ae p R es ult s ( D ev elo pe d w ith bl oc k ag e )
The peak water level during the above event at reporting point 1 was 106.54m AHD. The peak water
level at point 2 is 105.36m AHD. Point 1 shows an increase of 0.02m compared to the developed case
without blockage. Point 2 shows an increase in peak water elevation of 0.15m compared to the
developed case without blockage.
The peak flow at flow line 10 was 44.17m3/s.
This is 2.69m3/s less than the existing case.
Sensitivity Case
A special blockage case has been run to determine the sensitivity of the model to blockage. For this
case items 3, 4, 5 and 6 have been considered 100% blocked. The result of this model run is a peak
water elevation of 107.93m AHD at point 1 and 105.42m AHD at point 2.
This event shows an increase of peak water elevation at point 1 of 1.41m at point 1 compared to the
developed model without blockage. This will still not affect the development property. At point 2 this
model shows an increase of 0.21m in peak water elevation.
This model is presented as a worst case scenario only is not considered to be a design event.
4.2.13 1 in 5 00 R e su lt s ( D ev elo pe d n o b lo ck ag e)
The peak water level during the above event at reporting point 1 was 106.63m AHD. The peak water
level at point 2 is 105.39m AHD. The developed case shows a decrease in peak water elevation of
0.03m at point 1. Point 2 also shows a decrease of 0.06m in peak water elevation.
The peak flow at flow line 10 was 51.90m3/s.
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This is 2.58m3/s less than the existing case.
4.2.14 1 in 50 0 R es ult s ( D e v elop ed w ith blo c ka g e)
The peak water level during the above event at reporting point 1 was 106.62m AHD. The peak water
level at point 2 is 105.54m AHD. The peak water level at point 1 is 0.01m less that the developed case
without blockage. Point 2 shows an increase in peak water elevation of 0.15m.
The peak flow at flow line 10 was 50.02m 3/s.
This is 4.46m3/s less than the existing case.
4.2.15 1 in 2 00 0 R es ult s ( D e v elop ed no b loc k ag e)
The peak water level during the above event at reporting point 1 was 106.69m AHD. The peak water
level at point 2 is 105.78m AHD. Point 1 shows a decrease in peak water elevation of 0.04m, while the
peak water elevation at point 2 has decreased by 0.08m.
The peak flow at flow line 10 was 55.10m 3/s.
This is 4.22m3/s less than the existing case.
4.2.16 1 in 20 0 0 Re su lt s ( D ev e lop ed w ith b lo ck a ge)
The peak water level during the above event at reporting point 1 was 106.75m AHD. The peak water
level at point 2 is 105.78m AHD. The applied blockage factors have resulted in an increase in peak
water elevation at point 1 of 0.06m and 0.21m at point 2.
The peak flow at flow line 10 was 56.90m3/s.
This is 2.42m3/s less than the existing case.
4.2.17 PM P R es ult s ( D ev e lo ped no bl oc k ag e)
The peak water level during the above event at reporting point 1 was 107.79m AHD. The peak water
level at point 2 is 106.70m AHD. Point 1 has an increase in peak water elevation of 0.15m. Point 2
shows an increase in peak water elevation of 0.01m.
The peak flow at flow line 10 was 182.72m 3/s.
This is 8.40m3/s less than the existing case.
4.2.18 PM P R es ult s ( D ev e lo ped w ith b lo c kag e)
The peak water level during the above event at reporting point 1 was 107.81m AHD. The peak water
level at point 2 is 106.71m AHD. The applied blockage factors show an increase of 0.02m at point 1
and 0.01m at point 2.
The peak flow at flow line 10 was 179.65m 3/s.
This is 11.47m3/s less than the existing case.
4. 3 Af flu x R es ult s an d Di sc us si on
Afflux for the above models has been measured using the GIS package “Global mapper”. Each 2D
water elevation grid has been imported into the above package and the differences between the
Flood Study 30
S19-007 122 & 144 Myall St, Cooroy
Page 70
developed and existing cases for each scenario were subtracted. For the events with blockage the
developed case with blockages peak water elevation grid was subtracted from its respective existing
case peak water elevation grid file.
For clarity only positive afflux results greater than 0.01m shall be displayed as negative afflux is not a
worsening.
Full detailed afflux maps and velocity afflux maps are presented in Appendix BC.
Velocity afflux is not present within neighbouring properties including road reserves for any of the
design events. The exception to this are small afflux (<0.25m/s) areas generally located west of
Ferrell’s Road and are not considered to be caused by the proposed development. Afflux within the
development site is present in small amounts (<0.50m/s) in some events, however as it is contained
within the development site it is not considered to be causing a nuisance to neighbouring properties or
developments. Velocity afflux maps for all design events are presented in Appendix BC.
4.3.1 50 % Ae p Af f l ux ( no b loc k ag e)
No afflux is recorded within neighbouring properties for this design event. Afflux is concentrated at the
location of a 1D/2D connection point from the developed portion of catchment 5.01. This afflux is due
to the concentration of flows and is localised within the gold course. No afflux is reported within the road
reserve or rail corridor. Please refer to Appendix BC for all flood and afflux maps.
4.3.2 50 % Ae p Af f l ux ( w it h blo ck ag e)
As per the above case no neighbouring properties experience afflux due to the proposed development.
4.3.3 20 % Ae p Af f l ux ( no b loc k ag e)
No afflux is reported in the vicinity of the proposed bridge or on neighbouring properties. A small amount
of afflux is recorded (0.01m) at the western side of the model (west of the Cooroy dolphins swimming
club) which is located at the 2D connection point. No changes are proposed in this location and so it is
not possible that this afflux is the result of the proposed development. As per the above case some
localised afflux is present at the discharge point of the developed portion of catchment 5.01.
4.3.4 20 % Ae p Af f l ux ( w it h blo ck ag e)
Afflux is as per the above case.
4.3.5 10 % Ae p Af f l ux ( no b loc k ag e)
The only afflux that is present in this model is located west of Ferrells road as per above models. The
maximum afflux in this location is 0.019m.
No afflux to neighbouring is reported in the vicinity of development except for the above mentioned
afflux north east of the development at the outlet of basin 2.
4.3.6 10 % Ae p Af f l ux ( w it h blo ck ag e)
Afflux is as per the above case.
4.3.7 5 % Ae p Af f lu x ( n o b l oc ka ge)
No afflux is reported within neighbouring properties except for small amounts located west of Myall
Street north of the development (maximum of 0.026m). Some afflux is reported in the vicinity of the
basin 2 which as described above is due to the concentration of flows to a single point. Additionally this
afflux is localised and does not affect the rail corridor or road reserve.
Flood Study 31
S19-007 122 & 144 Myall St, Cooroy
Page 71
4.3.8 5 % Ae p Af f lu x ( w it h blo ck ag e)
Afflux is as per the above case. Afflux reported west of Myall Street, North West of the development is
not present in this scenario.
4.3.9 2 % Ae p Af f lu x ( n o b l oc ka ge)
The 2% AEP design event shows an afflux surrounding the intersection of the proposed bridge with
Myall St. The maximum afflux in this area 0.142m. This afflux is due to the road reserve being filled for
the construction of the VXO leading to the proposed bridge. When the water level breaches this point
in the existing case the elevation of the water is lower due to the ground level being lower. This is
causing the afflux map to show an increase in peak elevation.
Outside of the vicinity of the bridge and proposed bioretention basins no afflux is reported.
Figure 14 below shows the afflux that is present in the above scenario.
Figure 14 – 2% AEP afflux extract.
4.3.10 2 % Ae p Af f lu x ( w it h blo ck ag e)
As with the above case afflux is reported in the vicinity of the proposed VXO (maximum of 0.165m) and
overflowing from the proposed bioretention basins. No afflux is reported on neighbouring properties
outside of the above mentioned properties.
Figure 15 below depicts the afflux described above.
Flood Study 32
S19-007 122 & 144 Myall St, Cooroy
Page 72
Figure 15 – 2% AEP afflux (With Blockage) extract.
4.3.11 1 % Ae p Af f lu x ( no bl oc ka ge)
As with the 2% models above afflux is present in the location of the proposed VXO. The maximum afflux
in this location is 0.131m. Some afflux has been reported in the presence of the proposed bridge
structure. This is contained to the development site and golf course and no afflux is reported on
neighbouring properties. As with the above case there is a small amount of afflux at the outlet of each
bioretention basin.
Flood Study 33
S19-007 122 & 144 Myall St, Cooroy
Page 73
Figure 15 – 1% AEP afflux extract.
4.3.12 1 % Ae p Af f lu x ( w it h blo ck ag e)
As with the above 1% model afflux is present in the location of the proposed VXO and bridge. Afflux in
the presence of the VXO is due to the need to fill the verge. The maximum afflux in this location is
0.128m. No afflux is reported on neighbouring properties due to the proposed development.
Flood Study 34
S19-007 122 & 144 Myall St, Cooroy
Page 74
5 CO N CLU S IO N
The proposed development consists of 245 lots to be developed with relocatable dwellings.
This report has outlined how the proposed development site (and the proposed bridge across the
existing natural channel) will not result in any nuisance to neighbouring properties for design events
ranging from the 50% to 1% AEP.
Hydrologic modelling has been completed using the integrated 1D/2D modelling program XPStorm.
XPStorm uses Laurenson’s method to compute unit hydrographs based on various user inputs. The
critical storm (defined as the storm producing the highest median peak flow for each duration) was run
through the 2D model using the modelling parameters detailed above to establish a base case.
The base case identified that flows approaching the existing infrastructure under Myall St to the South-
west of the development overtop Myall St during the 50% AEP event and flow through the development
site through the natural channel.
The proposed bridge crossing has been designed to maintain the flow widths of the existing natural
channel to ensure that no adverse effects occur on neighbouring properties. No filling outside of the
bridge abutments is proposed within the existing channel.
The developed models have shown a decrease in peak water elevation upstream of the proposed
bridge.
Peak flows downstream of the development site have been reported to determine the effect of the
proposed bridge and development on the downstream flow condition. It was found for all cases that
peak flows downstream of the development have decreased. This is attributed to the modelling of the
stormwater detention system detailed in the separate SWMR by Westera Partners.
Afflux has been checked for all design events. No afflux has been reported within neighbouring
properties or the road reserve for events upto and including the 5% AEP. Afflux shown in the 2% and
1% is located within the development property and golf course and has been attributed to the proposed
VXO off of Myall St and the overflow from the proposed bioretention basins associated the proposed
development.
As peak water levels upstream of the proposed bridge and peak flows downstream of the bridge are
lower for each respective design event it is deemed that the bridge does not have any adverse impact
on the conveyance of flow through the site up to the 1% AEP design event. Additionally afflux mapping
of water elevation and flow velocity have shown that no additional nuisance will occur due to the
presence of the development.
Flood Study 35
S19-007 122 & 144 Myall St, Cooroy
Page 75
6 AP P E N D IC E S
6. 1 Ap p end ix B A – C at c h ment L a yout
Flood Study BA
S19-007 122 & 144 Myall St, Cooroy
Page 76
BA - Catchment Layout 1X Append
Page 77
BA - Developed Catchment Layout
OT Ea Sa =
- te ee Se * oi
- b, ;
: 2S i
és ta, See
Appendix
2
Page 78
6. 2 Ap p end ix B B – R epo r t i ng po int s and fl ow l ine l oc at ion s
Flood Study BB
S19-007 122 & 144 Myall St, Cooroy
Page 79
a Ae Point 2 ~ 7 © Point 1§ pa * re ay)
Page 80
6. 3 Ap p end ix B C – Fl ood M aps an d Af flu x M aps
Flood Study BC
S19-007 122 & 144 Myall St, Cooroy
[OCR of page images]
6.3 Appendix BC — Flood Maps and Afflux Maps
Flood Study BC
$19-007 122 & 144 Myall St, Cooroy
Page 81
S| o. oO a 7c o co. fu 7 & | * oS = OD & shad fon * aa) OW aa) < 50%
Page 82
Flood Depth Maximum ing t AEP Exis 20% Fai | yl WN or 3.5 3.0 2.0m ES 0 0.5 0.0 Om
Page 83
Flood Depth Maximum ing t AEP Exis 10% Fai | yl WN or 3.0 2.5) 2.0 1.5 0 1 Om
Page 84
Flood Depth Maximum ing t 5% AEP Exis SF; 3.5 3.0 2.5 2.0 1.5m 0 1 0.5m 0.0 Om
Page 85
Flood Depth imum Maxi ting 2% AEP Exis 3.8 2B) y ae ™ 3.0 23D 2.0 0 1 Om
Page 86
Flood Depth Maximum ing t 1% AEP Exis 4.0 SD 3.0 2.0 5 1 Om 1 0.5 Om
Page 87
Flood Depth imum Maxi ing 1St 500 Exi mM ] ii 4.0 3.5 3.0 m 2.5 1.0m 0.5 Om
Page 88
Il in 2000 Existing Maximum Flood Depth = ae Wet | i 7 e os z z 5 a a = a os S S S S Pies va) o + nm nN = So
Page 89
PMP Existing Maximum Flood Depth
Page 90
Flood Depth imum AEP Developed Maxi 50% l 3 3.0 2.5 2.0 SD 1 0.5 0 Om
Page 91
Flood Depth imum AEP Developed Maxi 20% 3.4 3.0 2.0 IS 0 1 0.5 0 Om
Page 92
Flood Depth imum AEP Developed Max 10% 3.0 2) 2.0 “5 0 1 0.5 0 Om
Page 93
Flood Depth imum " AEP Developed Max 5% SF; 3.5 3.0 2 2.0 y 1 0 1 0.5 0 Om
Page 94
Flood Depth imum AEP Developed Maxi 2% 3.8 3.5 3.0 aa 2.0 eS) 1 0 1 0.5 Om
Page 95
Flood Depth imum AEP Developed Maxi 1% 4.0 3.5 3.0 2 5 1 0 1 0.5 Om
Page 96
Flood Depth imum 1 in 500 Developed Max 4.7 4.5 4.0 3.5 3.0 2S Pe 0. 1. 1 0.5 Om
Page 97
Flood Depth imum 2000 Developed Maxi 1 in 532 5.0 4.0 2.0 1 0 Om
Page 98
Flood Depth imum PMP Developed Max 7.0 6.0 5.0 4.0 3.0 2.0 Om 1 0 Om
Page 99
Flood Depth (With Blockage) imum AEP Developed Max 50% 3.4 3.0 2.5 2. 1.0 0.5 Om
Page 100
Flood Depth (With Blockage) imum AEP Developed Max 20% 3.5 3.0 2: 2.0 1.5 0 Om
Page 101
Flood Depth (With Blockage) imum AEP Developed Max 10% 3.5 3.0 2: 2.0 1.5 0 Om
Page 102
Flood Depth (With Blockage) imum AEP Developed Maxi 5% 3.8 3.5 3.0 20) 2.0 iS 1.0 0.5 Om
Page 103
Flood Depth (With Blockage) imum AEP Developed Maxi 2% 3.8 3.5 3.0 2.0 0 17 1 0.5 Om
Page 104
Flood Depth (With Blockage) imum AEP Developed Maxi % ] 4.0 3.5 3 2. 5 1 0 1 0.5 Om
Page 105
Flood Depth (100% Blockage Sensitivity) AEP Developed Maximum % l 4.3 4.0 35 3 5 0 1 0.5 Om
Page 106
th Blockage) Maximum Flood Depth 500 Developed (Wi mM l 4.8 4.5 4.0 3.5 3.0 2.5 2.0 0.5 0 Om
Page 107
th Blockage) Maximum Flood Depth 2000 Developed (Wi mM l 532 5.0 4.0 2 1 0 Om
Page 108
th Blockage) Maximum Flood Depth PMP Developed (Wi 8.0 7.0 6.0 5 4. 3.0 2.0 0 1 0 Om
Page 109
AEP Afflux Map 50%
Page 110
AEP Afflux Map 20% 0.297 m 0.280 m 0.260 m 0.240 m 0.220 m 0.200 m 0.180 m 0.160 m 0.140 m 0.120 m 0.080 m 0.060 m 0.040 m 0.020 m 0.010 m Om
Page 111
AEP Afflux Map 5% 0.258 m 0.250 m 0.220 m 0.210 m 0.200 m 0.190 m 0.180 m 0.170 m 0.160 m 0.150 m 0.140 m 0.130 m 0.120 m 0.110 m 0.070 m 0.060 m 0.050 m 0.030 m 0.020 m 0.010 m Om
Page 112
AEP Afflux Map 10% 0.278 m 0.260 m 0.240 m 0.220 m 0.200 m 0.180 m 0.160 m 0.140 m 0.120 m 0.100 m 0.060 m 0.040 m 0.020 m 0.010 m Om
Page 113
a = * > a < Qu aa) < 2%
Page 114
a = * > a < Qu aa) < 1%
Page 115
With Blockage) AEP Afflux Map ( 50% ui Lae
Page 116
With Blockage) AEP Afflux Map ( 20%
Page 117
With Blockage) as Ao AEP Afflux Map ( 10% 0.272 m 0.260 m 0.240 m 0.220 m 0.200 m 0.180 m 0.160 m 0.140 m 0.120 m 0.100 m 0.080 m 0.060 m 0.040 m 0.020 m 0.010 m
Page 118
With Blockage) AEP Afflux Map ( 5% 0.250 m 0.240 m 0.230 m 0.220 m 0.210 m 0.200 m 0.190 m 0.180 m 0.170 m 0.160 m 0.150 m 0.140 m 0.130 m 0.120 m 0.110 m 0.070 m 0.060 m 0.030 m 0.020 m 0.010 m Om
Page 119
AEP Afflux Map (With Blockage) 2%
Page 120
AEP Afflux Map (With Blockage) % l 0.219 m 0.210 m 0.200 m 0.190 m 0.180 m 0.170 m 0.160 m 0.150 m 0.140 m 0.130 m 0.120 m 0.110 m 0.100 m 0.070 m 0.060 m 0.050 m 0.040 m 0.030 m 0.020 m 0.010 m Om
Page 121
eS x | Sf re < 2 oO = > a aa < 50% Pen: i LTPP: i a ow 0.800 m/s 0.760 m/s 0.720 m/s 0.680 m/s 0.640 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s 0.440 m/s 0.400 m/s 0.360 m/s 0.320 m/s 0.280 m/s 0.240 m/s 0.200 m/s 0.160 m/s 0.120 m/s 0.080 m/s 0.040 m/s 0.010 m/s
Page 122
0.708 m/s 0.680 m/s 0.640 m/s 0.600 m/s 0.400 m/s 0.360 m/s 0.320 m/s 0.120 m/s 0.040 m/s 20% A EP Velocity Afflux
Page 123
a 8 x | > re < 2 oO = > a aa < oS S — AM a Fs epee a at 4 poe Meeps be as Pa f ak LOR ee PN Oe Ser ae a tos Re 0.840 m/s 0.800 m/s 0.760 m/s 0.720 m/s 0.680 m/s 0.640 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s 0.440 m/s 0.400 m/s 0.360 m/s 0.320 m/s 0.280 m/s 0.240 m/s 0.200 m/s 0.160 m/s 0.080 m/s 0.040 m/s 0.010 m/s
Page 124
ty Afflux Map
5% AEP Veloci
0.655 m/s
0.640 m/s
0.600 m/s
0.560 m/s
0.520 m/s
0.480 m/s =
0.440 m/s =
0.400 m/s =
0.360 m/s =
0.320 m/s =
0.280 m/s —
0.240 m/s
0.200 m/s
0.160 m/s
0.120 m/s
0.080 m/s
0.040 m/s
0.010 m/s
Page 125
ty Afflux Map 1 ° = O > oO. sal < 2%
Page 126
ty Afflux Map 1 o LS O > oO aa < 1% é Meeps be as pid me LE UT cc a Ph ested parte Tide Ser eRe 0.840 m/s 0.800 m/s 0.760 m/s 0.720 m/s 0.680 m/s 0.640 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s 0.440 m/s 0.400 m/s 0.360 m/s 0.320 m/s 0.280 m/s 0.240 m/s 0.200 m/s 0.160 m/s 0.080 m/s 0.040 m/s 0.010 m/s
Page 127
ty Afflux Map (With Blockage) i AEP Veloc 50% 0.680 m/s 0.640 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s — 0.440 m/s = 0.400 m/s = 0.360 m/s — 0.320 m/s — 0.280 m/s = 0.240 m/s 0.200 m/s 0.160 m/s 0.120 m/s 0.080 m/s 0.040 m/s 0.010 m/s Om
Page 128
ty Afflux Map (With Blockage) i AEP Veloc 20% 0.720 m/s 0.680 m/s 0.640 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s — at 0.440 m/s 0.400 m/s — 0.360 m/s — 0.320 m/s = 0.280 m/s = 0.240 m/s 0.200 m/s 0.160 m/s 0.120 m/s 0.080 m/s 0.040 m/s 0.010 m/s Om
Page 129
With Blockage) ty Afflux Map ( i AEP Veloc 10% 0.629 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s — 0.440 m/s = 0.400 m/s = 0.360 m/s + 0.320 m/s = 0.280 m/s = 0.240 m/s 0.200 m/s 0.160 m/s 0.120 m/s 0.080 m/s 0.040 m/s 0.010 m/s Om
Page 130
ty Afflux Map (With Blockage)
AEP Veloci
5%
0.720 m/s
0.680 m/s
0.640 m/s
0.600 m/s
0.560 m/s
0.520 m/s
0.480 m/s. —}
0.440 m/s =
0.400 m/s —
0.360 m/s +
|
0.320 m/s +
0.280 m/s —
0.240 m/s
0.200 m/s
0.160 m/s
0.120 m/s
0.080 m/s
0.040 m/s
0.010 m/s
Om
Page 131
— © 2 | 3 ~~ oO iY mM ¥ S| Ei £ > = = < es AEP Veloci 2% 0.960 m/s 0.920 m/s 0.880 m/s 0.840 m/s 0.800 m/s 0.760 m/s 0.720 m/s 0.680 m/s 0.640 m/s 0.600 m/s 0.560 m/s 0.520 m/s 0.480 m/s 0.440 m/s 0.400 m/s 0.360 m/s 0.320 m/s 0.280 m/s 0.240 m/s 0.200 m/s 0.160 m/s 0.080 m/s 0.040 m/s 0.010 m/s
Page 132
0.860 m/s 0.840 m/s 0.800 m/s 0.760 m/s 0.640 m/s 0.560 m/s 0.480 m/s 0.440 m/s 0.360 m/s 0.280 m/s 0.240 m/s 0.200 m/s 0.160 m/s 0.080 m/s 0.040 m/s 0.010 m/s l % AEP Veloci ty Afflux M ap (Wit " iodo w
Page 133
6. 4 Ap p end ix B D – AR R Dat aH ub D ata
Flood Study BD
S19-007 122 & 144 Myall St, Cooroy
[OCR of page images]
6.4 Appendix BD — ARR DataHub Data
Flood Study BD
$19-007 122 & 144 Myall St, Cooroy
Page 134
20/06/2019 Results | ARR Data Hub
ATTENTION: This site was updated recently, changing some of the functionality. Please see the changelog
(./changelog) for further information
Australian Rainfall & Runoff Data Hub - Results
Input Data
Longitude 152.897
Latitude -26.445
Selected Regions (clear)
River Region show
ARF Parameters show
Storm Losses show
Temporal Patterns show
Areal Temporal Patterns show
BOM IFDs show
Median Preburst Depths and Ratios show
10% Preburst Depths show
25% Preburst Depths show
75% Preburst Depths show
90% Preburst Depths show
Interim Climate Change Factors show
+
−
https://data.arr-software.org 1/9
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20/06/2019 Results | ARR Data Hub
Leaflet (http://leafletjs.com) | Map data © OpenStreetMap (http://openstreetmap.org) contributors, CC-BY-SA
(http://creativecommons.org/licenses/by-sa/2.0/), Imagery © Mapbox (http://mapbox.com)
Data
River Region
Division North East Coast
River Number 38
River Name Mary River (Qld)
Layer Info
Time Accessed 20 June 2019 01:40PM
Version 2016_v1
ARF Parameters
b −d
ARF = M in {1, [1 − a (Area − clog10 Duration) Duration
f g
+ eArea Duration (0.3 + log10 AEP )
Duration
iArea
+ h10 1440
(0.3 + log10 AEP )]}
Zone a b c d e f g h i
East Coast North 0.327 0.241 0.448 0.36 0.00096 0.48 -0.21 0.012 -0.0013
Short Duration ARF
0.265 −0.36
ARF = M in [1, 1 − 0.287 (Area − 0.439log10 (Duration)) . Duration
−3 0.226 0.125
+ 2.26 x 10 x Area . Duration (0.3 + log (AEP ))
10
2
(Duration−180)
0.213 −0.021
+ 0.0141 x Area x 10 1440 (0.3 + log (AEP ))]
10
https://data.arr-software.org 2/9
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Layer Info
Time Accessed 20 June 2019 01:40PM
Version 2016_v1
Storm Losses
Note: Burst Loss = Storm Loss - Preburst
Note: These losses are only for rural use and are NOT FOR DIRECT USE in urban areas
ID 29194.0
Storm Initial Losses (mm) 32.0
Storm Continuing Losses (mm/h) 2.6
Layer Info
Time Accessed 20 June 2019 01:40PM
Version 2016_v1
Temporal Patterns | Download (.zip) (static/temporal_patterns/TP/ECnorth.zip)
code ECnorth
Label East Coast North
Layer Info
Time Accessed 20 June 2019 01:40PM
Version 2016_v2
Areal Temporal Patterns | Download (.zip)
(./static/temporal_patterns/Areal/Areal_ECnorth.zip)
code ECnorth
arealabel East Coast North
Layer Info
Time Accessed 20 June 2019 01:40PM
Version 2016_v2
https://data.arr-software.org 3/9
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BOM IFDs
Click here (http://www.bom.gov.au/water/designRainfalls/revised-ifd/?
year=2016&coordinate_type=dd&latitude=-26.445&longitude=152.897&sdmin=true&sdhr=true&sdday=true&user_label=)
to obtain the IFD depths for catchment centroid from the BoM website
Layer Info
Time Accessed 20 June 2019 01:40PM
Median Preburst Depths and Ratios
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 2.5 7.1 10.2 13.2 10.8 8.9
(0.058) (0.124) (0.151) (0.169) (0.118) (0.088)
90 (1.5) 2.8 8.6 12.5 16.2 16.1 16.0
(0.056) (0.127) (0.155) (0.174) (0.147) (0.131)
120 (2.0) 7.4 13.6 17.8 21.7 19.9 18.5
(0.133) (0.178) (0.195) (0.206) (0.159) (0.132)
180 (3.0) 17.0 25.6 31.2 36.7 39.1 40.9
(0.261) (0.282) (0.287) (0.290) (0.259) (0.240)
360 (6.0) 19.3 43.6 59.6 75.0 106.1 129.3
(0.222) (0.352) (0.398) (0.425) (0.499) (0.536)
720 (12.0) 16.1 38.6 53.6 68.0 83.2 94.7
(0.138) (0.227) (0.257) (0.274) (0.276) (0.275)
1080 (18.0) 8.8 35.0 52.3 69.0 101.3 125.6
(0.064) (0.171) (0.208) (0.229) (0.275) (0.298)
1440 (24.0) 10.6 26.3 36.7 46.7 96.4 133.7
(0.069) (0.114) (0.128) (0.136) (0.229) (0.276)
2160 (36.0) 1.4 16.4 26.3 35.8 67.1 90.5
(0.008) (0.061) (0.078) (0.088) (0.133) (0.156)
2880 (48.0) 0.0 10.9 18.2 25.1 50.8 70.0
(0.000) (0.037) (0.049) (0.055) (0.090) (0.107)
4320 (72.0) 0.0 4.4 7.3 10.1 14.9 18.5
(0.000) (0.013) (0.017) (0.020) (0.023) (0.025)
Layer Info
Time 20 June 2019 01:40PM
Accessed
https://data.arr-software.org 4/9
[OCR of page images]
20/06/2019 Results | ARR Data Hub
BOM IFDs
Click here (http://www.bom.gov.au/water/designRainfalls/revised-ifd/?
year=2016&coordinate_type=dd&latitude=-26.445&longitude=152.897 &sdmin=true&sdhr=true&sdday=true&user_label=)
to obtain the IFD depths for catchment centroid from the BoM website
Layer Info
Time Accessed 20 June 2019 01:40PM
Median Preburst Depths and Ratios
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 2.5 7.1 10.2 13.2 10.8 8.9
(0.058) (0.124) (0.151) (0.169) (0.118) (0.088)
90 (1.5) 2.8 8.6 12.5 16.2 16.1 16.0
(0.056) (0.127) (0.155) (0.174) (0.147) (0.131)
120 (2.0) 74 13.6 17.8 21.7 19.9 18.5
(0.133) (0.178) (0.195) (0.206) (0.159) (0.132)
180 (3.0) 17.0 25.6 31.2 36.7 39.1 40.9
(0.261) (0.282) (0.287) (0.290) (0.259) (0.240)
360 (6.0) 19.3 43.6 59.6 75.0 106.1 129.3
(0.222) (0.352) (0.398) (0.425) (0.499) (0.536)
720 (12.0) 16.1 38.6 53.6 68.0 83.2 94.7
(0.138) (0.227) (0.257) (0.274) (0.276) (0.275)
1080 (18.0) 8.8 35.0 52.3 69.0 101.3 125.6
(0.064) (0.171) (0.208) (0.229) (0.275) (0.298)
1440 (24.0) 10.6 26.3 36.7 46.7 96.4 133.7
(0.069) (0.114) (0.128) (0.136) (0.229) (0.276)
2160 (36.0) 1.4 16.4 26.3 35.8 67.1 90.5
(0.008) (0.061) (0.078) (0.088) (0.133) (0.156)
2880 (48.0) 0.0 10.9 18.2 25.1 50.8 70.0
(0.000) (0.037) (0.049) (0.055) (0.090) (0.107)
4320 (72.0) 0.0 44 7.3 10.1 14.9 18.5
(0.000) (0.013) (0.017) (0.020) (0.023) (0.025)
Layer Info
Time 20 June 2019 01:40PM
Accessed
https://data.arr-software.org Al9
Page 138
20/06/2019 Results | ARR Data Hub
Version 2018_v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
10% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
90 (1.5) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
120 (2.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
180 (3.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
360 (6.0) 0.0 0.0 0.0 0.0 1.2 2.2
(0.000) (0.000) (0.000) (0.000) (0.006) (0.009)
720 (12.0) 0.0 0.6 0.9 1.3 0.6 0.0
(0.000) (0.003) (0.005) (0.005) (0.002) (0.000)
1080 (18.0) 0.0 0.4 0.7 0.9 19.3 33.1
(0.000) (0.002) (0.003) (0.003) (0.052) (0.079)
1440 (24.0) 0.0 0.0 0.0 0.0 24.9 43.6
(0.000) (0.000) (0.000) (0.000) (0.059) (0.090)
2160 (36.0) 0.0 0.0 0.0 0.0 3.1 5.5
(0.000) (0.000) (0.000) (0.000) (0.006) (0.009)
2880 (48.0) 0.0 0.0 0.0 0.0 3.0 5.2
(0.000) (0.000) (0.000) (0.000) (0.005) (0.008)
4320 (72.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018_v1
https://data.arr-software.org 5/9
[OCR of page images]
20/06/2019 Results | ARR Data Hub
Version 2018 _v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
10% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
90 (1.5) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
120 (2.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
180 (3.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
360 (6.0) 0.0 0.0 0.0 0.0 1.2 2.2
(0.000) (0.000) (0.000) (0.000) (0.006) (0.009)
720 (12.0) 0.0 0.6 0.9 1.3 0.6 0.0
(0.000) (0.003) (0.005) (0.005) (0.002) (0.000)
1080 (18.0) 0.0 0.4 0.7 0.9 19.3 33.1
(0.000) (0.002) (0.003) (0.003) (0.052) (0.079)
1440 (24.0) 0.0 0.0 0.0 0.0 24.9 43.6
(0.000) (0.000) (0.000) (0.000) (0.059) (0.090)
2160 (36.0) 0.0 0.0 0.0 0.0 3.1 5.5
(0.000) (0.000) (0.000) (0.000) (0.006) (0.009)
2880 (48.0) 0.0 0.0 0.0 0.0 3.0 5.2
(0.000) (0.000) (0.000) (0.000) (0.005) (0.008)
4320 (72.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018 _v1
https://data.arr-software.org 5/9
Page 139
20/06/2019 Results | ARR Data Hub
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
25% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 0.0 0.3 0.6 0.8 0.9 1.0
(0.000) (0.006) (0.008) (0.010) (0.010) (0.010)
90 (1.5) 0.0 0.4 0.7 0.9 1.8 2.4
(0.000) (0.006) (0.008) (0.010) (0.016) (0.020)
120 (2.0) 0.0 1.1 1.8 2.5 3.4 4.1
(0.000) (0.015) (0.020) (0.024) (0.027) (0.029)
180 (3.0) 0.0 1.2 2.0 2.8 4.3 5.4
(0.000) (0.013) (0.018) (0.022) (0.028) (0.032)
360 (6.0) 2.5 4.3 5.5 6.6 28.8 45.3
(0.029) (0.035) (0.037) (0.038) (0.135) (0.188)
720 (12.0) 0.3 6.4 10.5 14.4 30.1 41.8
(0.003) (0.038) (0.050) (0.058) (0.100) (0.122)
1080 (18.0) 0.0 4.5 7.5 10.3 37.9 58.6
(0.000) (0.022) (0.030) (0.034) (0.103) (0.139)
1440 (24.0) 0.0 3.7 6.2 8.5 35.6 55.8
(0.000) (0.016) (0.022) (0.025) (0.084) (0.115)
2160 (36.0) 0.0 0.2 0.4 0.6 13.9 23.9
(0.000) (0.001) (0.001) (0.001) (0.028) (0.041)
2880 (48.0) 0.0 0.0 0.0 0.0 8.9 15.6
(0.000) (0.000) (0.000) (0.000) (0.016) (0.024)
4320 (72.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018_v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
https://data.arr-software.org 6/9
[OCR of page images]
20/06/2019
Note
Results | ARR Data Hub
Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
25% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 0.0 0.3 0.6 0.8 0.9 1.0
(0.000) (0.006) (0.008) (0.010) (0.010) (0.010)
90 (1.5) 0.0 0.4 0.7 0.9 1.8 2.4
(0.000) (0.006) (0.008) (0.010) (0.016) (0.020)
120 (2.0) 0.0 1.1 1.8 2.5 3.4 41
(0.000) (0.015) (0.020) (0.024) (0.027) (0.029)
180 (3.0) 0.0 1.2 2.0 2.8 4.3 5.4
(0.000) (0.013) (0.018) (0.022) (0.028) (0.032)
360 (6.0) 2.5 4.3 5.5 6.6 28.8 45.3
(0.029) (0.035) (0.037) (0.038) (0.135) (0.188)
720 (12.0) 0.3 6.4 10.5 14.4 30.1 41.8
(0.003) (0.038) (0.050) (0.058) (0.100) (0.122)
1080 (18.0) 0.0 45 7.5 10.3 37.9 58.6
(0.000) (0.022) (0.030) (0.034) (0.103) (0.139)
1440 (24.0) 0.0 3.7 6.2 8.5 35.6 55.8
(0.000) (0.016) (0.022) (0.025) (0.084) (0.115)
2160 (36.0) 0.0 0.2 0.4 0.6 13.9 23.9
(0.000) (0.001) (0.001) (0.001) (0.028) (0.041)
2880 (48.0) 0.0 0.0 0.0 0.0 8.9 15.6
(0.000) (0.000) (0.000) (0.000) (0.016) (0.024)
4320 (72.0) 0.0 0.0 0.0 0.0 0.0 0.0
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018 _v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
https://data.arr-software.org
values remain unchanged.
6/9
Page 140
20/06/2019 Results | ARR Data Hub
75% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 37.7 39.2 40.2 41.1 37.3 34.4
(0.886) (0.680) (0.592) (0.528) (0.409) (0.339)
90 (1.5) 49.0 62.8 71.9 80.7 95.4 106.5
(0.987) (0.925) (0.894) (0.869) (0.872) (0.870)
120 (2.0) 43.9 75.8 96.9 117.2 122.1 125.9
(0.791) (0.992) (1.066) (1.112) (0.977) (0.897)
180 (3.0) 60.0 91.7 112.6 132.7 169.8 197.6
(0.921) (1.010) (1.036) (1.047) (1.123) (1.159)
360 (6.0) 54.3 106.9 141.8 175.2 243.1 294.0
(0.626) (0.864) (0.946) (0.993) (1.144) (1.219)
720 (12.0) 44.0 104.7 145.0 183.5 207.6 225.7
(0.378) (0.615) (0.694) (0.740) (0.689) (0.656)
1080 (18.0) 45.4 90.4 120.2 148.8 231.6 293.5
(0.331) (0.443) (0.477) (0.494) (0.629) (0.696)
1440 (24.0) 34.9 71.8 96.3 119.7 212.5 282.0
(0.227) (0.312) (0.337) (0.349) (0.504) (0.582)
2160 (36.0) 20.0 59.8 86.1 111.3 142.0 164.9
(0.113) (0.222) (0.256) (0.274) (0.282) (0.283)
2880 (48.0) 17.2 56.4 82.3 107.1 156.7 193.9
(0.089) (0.190) (0.221) (0.237) (0.278) (0.296)
4320 (72.0) 2.9 30.0 48.0 65.2 85.0 99.8
(0.013) (0.090) (0.114) (0.127) (0.132) (0.133)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018_v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
https://data.arr-software.org 7/9
[OCR of page images]
20/06/2019
Results | ARR Data Hub
75% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 37.7 39.2 40.2 41.1 37.3 34.4
(0.886) (0.680) (0.592) (0.528) (0.409) (0.339)
90 (1.5) 49.0 62.8 71.9 80.7 95.4 106.5
(0.987) (0.925) (0.894) (0.869) (0.872) (0.870)
120 (2.0) 43.9 75.8 96.9 117.2 122.1 125.9
(0.791) (0.992) (1.066) (1.112) (0.977) (0.897)
180 (3.0) 60.0 91.7 112.6 132.7 169.8 197.6
(0.921) (1.010) (1.036) (1.047) (1.123) (1.159)
360 (6.0) 54.3 106.9 141.8 175.2 243.1 294.0
(0.626) (0.864) (0.946) (0.993) (1.144) (1.219)
720 (12.0) 44.0 104.7 145.0 183.5 207.6 225.7
(0.378) (0.615) (0.694) (0.740) (0.689) (0.656)
1080 (18.0) 45.4 90.4 120.2 148.8 231.6 293.5
(0.331) (0.443) (0.477) (0.494) (0.629) (0.696)
1440 (24.0) 34.9 71.8 96.3 119.7 212.5 282.0
(0.227) (0.312) (0.337) (0.349) (0.504) (0.582)
2160 (36.0) 20.0 59.8 86.1 111.3 142.0 164.9
(0.113) (0.222) (0.256) (0.274) (0.282) (0.283)
2880 (48.0) 17.2 56.4 82.3 107.1 156.7 193.9
(0.089) (0.190) (0.221) (0.237) (0.278) (0.296)
4320 (72.0) 2.9 30.0 48.0 65.2 85.0 99.8
(0.013) (0.090) (0.114) (0.127) (0.132) (0.133)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018 _v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
https://data.arr-software.org
values remain unchanged.
7/9
Page 141
20/06/2019 Results | ARR Data Hub
90% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 105.2 138.0 159.8 180.6 155.5 136.7
(2.477) (2.398) (2.356) (2.321) (1.707) (1.349)
90 (1.5) 107.1 153.3 183.9 213.2 240.2 260.5
(2.156) (2.258) (2.286) (2.297) (2.194) (2.128)
120 (2.0) 118.1 178.1 217.8 255.9 248.7 243.3
(2.127) (2.329) (2.394) (2.428) (1.990) (1.735)
180 (3.0) 144.7 216.0 263.2 308.5 308.8 309.1
(2.221) (2.379) (2.421) (2.434) (2.043) (1.813)
360 (6.0) 179.5 224.6 254.4 283.0 471.3 612.3
(2.070) (1.815) (1.697) (1.604) (2.218) (2.540)
720 (12.0) 118.9 190.3 237.6 282.9 364.4 425.5
(1.023) (1.118) (1.138) (1.140) (1.209) (1.237)
1080 (18.0) 101.3 156.7 193.4 228.6 351.7 443.9
(0.738) (0.768) (0.767) (0.759) (0.955) (1.053)
1440 (24.0) 99.7 147.7 179.4 209.9 326.6 414.1
(0.649) (0.642) (0.628) (0.611) (0.774) (0.854)
2160 (36.0) 66.6 122.4 159.3 194.7 310.2 396.7
(0.376) (0.455) (0.474) (0.479) (0.616) (0.682)
2880 (48.0) 53.8 136.2 190.9 243.2 283.2 313.1
(0.277) (0.460) (0.513) (0.538) (0.503) (0.479)
4320 (72.0) 40.0 73.0 94.8 115.7 153.8 182.4
(0.185) (0.220) (0.226) (0.225) (0.239) (0.242)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018_v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
values remain unchanged.
https://data.arr-software.org 8/9
[OCR of page images]
20/06/2019
Results | ARR Data Hub
90% Preburst Depths
Values are of the format depth (ratio) with depth in mm
min (h)\AEP(%) 50 20 10 5 2 1
60 (1.0) 105.2 138.0 159.8 180.6 155.5 136.7
(2.477) (2.398) (2.356) (2.321) (1.707) (1.349)
90 (1.5) 107.1 153.3 183.9 213.2 240.2 260.5
(2.156) (2.258) (2.286) (2.297) (2.194) (2.128)
120 (2.0) 118.1 178.1 217.8 255.9 248.7 243.3
(2.127) (2.329) (2.394) (2.428) (1.990) (1.735)
180 (3.0) 144.7 216.0 263.2 308.5 308.8 309.1
(2.221) (2.379) (2.421) (2.434) (2.043) (1.813)
360 (6.0) 179.5 224.6 254.4 283.0 471.3 612.3
(2.070) (1.815) (1.697) (1.604) (2.218) (2.540)
720 (12.0) 118.9 190.3 237.6 282.9 364.4 425.5
(1.023) (1.118) (1.138) (1.140) (1.209) (1.237)
1080 (18.0) 101.3 156.7 193.4 228.6 351.7 443.9
(0.738) (0.768) (0.767) (0.759) (0.955) (1.053)
1440 (24.0) 99.7 147.7 179.4 209.9 326.6 414.1
(0.649) (0.642) (0.628) (0.611) (0.774) (0.854)
2160 (36.0) 66.6 122.4 159.3 194.7 310.2 396.7
(0.376) (0.455) (0.474) (0.479) (0.616) (0.682)
2880 (48.0) 53.8 136.2 190.9 243.2 283.2 313.1
(0.277) (0.460) (0.513) (0.538) (0.503) (0.479)
4320 (72.0) 40.0 73.0 94.8 115.7 153.8 182.4
(0.185) (0.220) (0.226) (0.225) (0.239) (0.242)
Layer Info
Time 20 June 2019 01:40PM
Accessed
Version 2018 _v1
Note Preburst interpolation methods for catchment wide preburst has been slightly altered. Point
https://data.arr-software.org
values remain unchanged.
8/9
The text continues on page 142.