Council archive · source document
Reference Document - Site Based Stormwater Management Plan · MCU21/0117.01
Plans and drawings: the text below has words only, no drawings.
REFERENCE DOCUMENT MCU21/0117.01 & OPW21/0199.01 NOOSA COUNCIL 12 JULY 2024 SITE BASED STORMWATER MANAGEMENT PLAN PROPOSED TOWNHOUSE DEVELOPMENT AT 5 PEARL STREET COOROY Prepared for Altum Property Group Attention: Rob McCready Document Reference 23098 - SBSMP/4 Record of Issue: Issue Status Author Date Checked Date Authorised Date 18 Sep 19 Sep Henry Morgan 20 Sep 0 For Review Rick Cui Darren Yuen 2023 2023 RPEQ 11950 2023 26 Sep 28 Sep Henry Morgan 29 Sep 1 For Approval Rick Cui Darren Yuen 2023 2023 RPEQ 11950 2023 17 Jan 17 Jan Henry Morgan 17 Jan 2 For Approval Rick Cui Winston Boon 2024 2024 RPEQ 11950 2024 18 Mar Henry Morgan 18 Mar Henry Morgan 18 Mar 3 For Approval Winston Boon 2024 RPEQ 11950 2024 RPEQ 11950 2024 08 May Henry Morgan 14 May Henry Morgan 14 May 4 For Approval Winston Boon 2024 RPEQ 11950 2024 RPEQ 11950 2024 This investigation and report has been authorised by Mr Henry Morgan, a Director of Morgan Consulting Engineers Pty Ltd. Henry J Morgan RPEQ 11950 Tuesday, 14 May 2024 D:\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Current\23098 - SBSMP - Rev 4.docx
See the original
The page text is free to read. Viewing or downloading an original file needs an account.
Log in to see the originalFull text of the other 59 pages
Page 2
23098 - SBSMP/4
Page 2
Table of Contents
1 INTRODUCTION ............................................................................................ 3
2 EXISTING SITE.............................................................................................. 4
2.1 The Site ................................................................................................ 4
2.2 Surrounding Area ...................................................................................... 4
3 PROPOSED DEVELOPMENT ............................................................................... 5
4 EXISTING DRAINAGE PATTERNS ......................................................................... 6
4.1 Existing Infrastructure ............................................................................... 6
4.2 Existing Drainage Patterns ........................................................................... 7
4.3 Lawful Point of Discharge............................................................................ 7
5 STORMWATER QUANTITY................................................................................. 8
5.1 Rational Method Assessment ........................................................................ 8
5.1.1 Design Storms ....................................................................................8
5.1.2 Rainfall Intensity ................................................................................8
5.1.3 Times of Concentration .........................................................................8
5.1.4 Runoff Coefficients ..............................................................................8
5.1.5 Peak Flows ........................................................................................9
5.2 Proposed Development Drainage ................................................................... 9
5.3 DRAINS Modelling Assessment ....................................................................... 9
5.3.1 Hydraulic Model Parameters ................................................................. 10
5.3.2 Design Storms .................................................................................. 10
5.3.3 Intensity Frequency Distribution ............................................................ 10
5.3.4 Pre-Development Model ...................................................................... 10
5.3.5 Post-Development Model ..................................................................... 11
5.3.6 Post-Development Mitigated Model – On-site Detention Tank .......................... 11
5.3.7 Comparison of Peak Flows at Lawful Point of Discharge ................................. 13
6 STORMWATER QUALITY ................................................................................ 15
6.1 State Planning Policy Assessment ................................................................ 15
6.2 Construction Phase ................................................................................. 15
6.3 Operational Phase .................................................................................. 17
6.3.1 Sources of Contaminants ..................................................................... 17
6.3.2 Proposed Treatment Train ................................................................... 18
6.3.3 Pollutant Export Modelling ................................................................... 18
6.3.4 MUSIC Modelling Parameters ................................................................. 18
6.3.5 MUSIC Modelling Results ...................................................................... 19
7 FLOODING ................................................................................................ 21
8 CONCLUSION ............................................................................................. 22
Appendix A DETAILED SITE SURVEY ........................................................................ 23
Appendix B PROPOSED DEVELOPMENT PLANS ............................................................ 24
Appendix C NSC INTERACTIVE MAPPING PLANS .......................................................... 25
Appendix D NSC WATER QUALITY AND DRAINAGE CODE ................................................ 26
Appendix E RATIONAL METHOD CALCULATIONS ......................................................... 27
Appendix F CONCEPT SITE LEVELS AND DRAINAGE PLAN ............................................... 28
Appendix G BOM IFD ......................................................................................... 29
Appendix H DRAINS PRE & POST DEVELOPMENT RESULTS .............................................. 30
Appendix I DRAINS POST DEVELOPMENT MITIGATED RESULTS ........................................ 31
Appendix J STORMWATER QUALITY OPERATION AND MAINTENANCE GUIDELINES .................. 32
Appendix K NSC FLOOD HAZARD OVERLAY MAP .......................................................... 33
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 3
23098 - SBSMP/4
Page 3
1 INTRODUCTION
This Site Based Stormwater Management Plan (SBSMP) has been prepared for the Proposed
Townhouse Development at 5 Pearl Street, Cooroy.
This SBSMP has been prepared to investigate the effects the development will have on stormwater
quantity and quality.
The objective of this SBSMP is to ensure that there is no adverse impact by the development on
the environmental value of the receiving waters during the construction and operational phases
of the development. This SBSMP will also provide recommendations to ensure that the post-
development peak outflow conditions are not greater than the pre-development peak outflow
conditions.
In order to achieve this objective, this SBSMP:
1. Describes the environmental setting of the development site and precinct;
2. Describes the nature of the proposed development as it relates to stormwater quality;
3. Calculates the peak flows for both pre and post-development conditions;
4. Calculates the detention volume if required to achieve the pre-development outflow in the
post-development state; and
5. Identifies potential sources of contaminants and describes the management techniques
designed to be employed on the site to achieve the water quality objectives.
The proposed development has been assessed against the following guidelines and planning
documents:
1. State Planning Policy 2017 (SPP 2017);
2. Urban Stormwater Quality Planning Guidelines 2010;
3. The Queensland Urban Drainage Manual (QUDM); and
4. Noosa Shire Council Plan 2020;
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 4
23098 - SBSMP/4
Page 4
2 EXISTING SITE
2.1 The Site
The subject site, comprised of Lot 2 on RP153798 and Lot 2 on RP64750 is approximately 2,274m2
(0.2274ha) in area. The site is currently occupied by two existing residential dwellings, with
associated sheds and garages. Trees and shrubs are scattered throughout the subject site.
The subject site generally slopes from the southwest (with an approximate height of 107.41m AHD)
towards the northeast (with an approximate height of 105.2m AHD). Existing access to the subject
site is currently provided from Pearl Street and Elm Street.
Refer to Figure 2.1 for a Locality Plan and Appendix A for the Detailed Site Survey.
N
Sapphire Street
Subject Site
Elm Street
Kauri Street
Pearl Street
Figure 2.1 – Locality Plan of Site and Surrounding Area
2.2 Surrounding Area
The site is located within the limits of the NSC region and is classified as Medium Density Residential
Zone. The site is surrounded by residential properties to the north and east and commercial
properties to the west and south. Cooroy Creek lies further west and Cooroy Train Station lies
further south west.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 5
23098 - SBSMP/4
Page 5
3 PROPOSED DEVELOPMENT
The Proposed Townhouse Development primarily involves:
1. Three buildings containing a mix of two and three-bed units;
2. Carparking spaces for residents and visitors;
3. Vehicular access via Pearl Street, south of the site; and
4. Dedicated landscaping and planting throughout the site.
Refer to Appendix B for the Proposed Development Plans.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 6
23098 - SBSMP/4
Page 6
4 EXISTING DRAINAGE PATTERNS
4.1 Existing Infrastructure
Data obtained from the NSC Interactive Mapping plans and detailed site survey indicate the
following existing drainage infrastructure:
1. Swale drain traversing the northern verge of Pearl Street, south of the site;
2. Swale drain traversing the eastern verge of Elm Street, west of the site;
3. A 300mm dia. to 600mm dia. stormwater line traversing the southern verge of Pearl Street,
south of the site; and
4. A 1350mm dia. to 1800mm dia. stormwater line traversing the eastern boundary of 11 Pearl
Street, east of the site.
Refer to Figure 4.1 for the existing stormwater infrastructure and drainage patterns and Appendix
C for the Noosa Council Interactive Mapping Plans.
N
Subject Site
Ø 1350
Elm Street
Ø 375
Ø 1800
Legend
Pearl Street
Sheet Flow Path
Stormwater Line Ø 300
Stormwater Pit Ø 600 Ø 750
Swale Drain
Headwall
Figure 4.1 – Existing Drainage Paths & Infrastructure
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 7
23098 - SBSMP/4
Page 7
4.2 Existing Drainage Patterns
Following an assessment of the existing site conditions and drainage infrastructure we can confirm
that the site has the following drainage patterns:
Roofwater Runoff
1. Roofwater runoff from the site is discharged onto the ground where it sheet flows to the
Environmental Management and Conservation Area, northeast of the site.
Surface Runoff
1. Surface runoff from the site sheet flows to the Environmental Management and
Conservation Area, northeast of the site.
External Catchment
1. There is an external ground catchment contributing runoff from 52 Elm Street, southwest
of the site, which sheet flows through the site to the Environmental Management and
Conservation Area, northeast of the site.
It is noted that all sheet flow traversing across the site becomes concentrated along the eastern
boundary of the site due to an existing bund along this boundary that was constructed as part of
7 Pearl Street. Concentrated flow along this boundary is directed to the Environmental
Management and Conservation Area, northeast of the site.
Refer to Figure 4.1 for a drainage schematic and Appendix A for the detailed site survey plan.
4.3 Lawful Point of Discharge
If the proposed development maintains pre-development flow conditions, the lawful point of
discharge (LPD) is the existing Environmental Management and Conservation Area, northeast of
the site.
In consideration of the site characteristics, surrounding topology and stormwater drainage
infrastructure, the aforementioned proposed lawful point of discharge is considered to be
compliant with the criteria for lawful point of discharge outlined in Section 3.9.1. of QUDM 2017
as per below:
i) The location of the proposed discharge point is under the lawful control of the local
government or other statutory authority from whom permission to discharge has been
received.
ii) The post development discharge will not cause an actionable nuisance, nor environmental
or property damage, as the existing flow characteristics and drainage patterns will be
maintained for the proposed development.
iii) Authority to discharge over affected properties will not be required as the proposed
drainage patterns does not impact surrounding properties adjacent to and downstream of
the subject site.
Refer to Section 5 outlining the Stormwater Quantity aspects of this site and Appendix D for the
Water Quality and Drainage Code.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 8
23098 - SBSMP/4
Page 8
5 STORMWATER QUANTITY
A roof and allotment drainage system is to be designed to comply with:
1. AS/NZS 3500.3:2015 - Plumbing and Drainage Part 3: Stormwater Drainage;
2. The Queensland Urban Drainage Manual (QUDM), and;
3. The Noosa Council Engineering Design Standards – Road, drainage and earthworks.
5.1 Rational Method Assessment
The Rational Method has been used to calculate the peak discharges from the site under the
existing (pre-development) and proposed (post-development) conditions.
5.1.1 Design Storms
As defined in the BRC Planning Scheme Policies the following design storms were adopted:
1. Minor Drainage System: 10 year ARI statistical flood (Q10 storm);
2. Major Drainage System: 100 year ARI statistical flood (Q100 storm).
5.1.2 Rainfall Intensity
Rainfall intensities for this study were obtained from the Australian Bureau of Meteorology.
5.1.3 Times of Concentration
Times of concentration (tc) were calculated as defined in the QUDM. Refer to Table 5-1 for the
adopted tc’s and Appendix E for tc calculations.
Table 5-1 – Adopted tc values
Pre development Post development
tc (mins) tc (mins)
9.7 5
5.1.4 Runoff Coefficients
The 10 year runoff coefficient’s (C10) were determined as defined in the QUDM. Refer to Table 5-2
below for the adopted C10 values.
Table 5-2 – Adopted C10 Values
Property State C10
Pre-development 0.75
Post-development 0.85
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 9
23098 - SBSMP/4
Page 9
5.1.5 Peak Flows
Refer to Table 5-3 for a summary of the predicted minor and major discharge rates for pre and
post development conditions and Appendix E for the Rational Method calculations.
Table 5-3 – Pre and Post Development Peak Flows
Property State Q2 (m3/s) Q5 (m3/s) Q10 (m3/s) Q20 (m3/s) Q50 (m3/s) Q100 (m3/s)
Pre development 0.045 0.068 0.083 0.099 0.125 0.143
Post development 0.062 0.094 0.116 0.139 0.176 0.199
As shown in Table 5-3, an increase in impervious surface areas will consequently increase
stormwater runoff peak flow rates from the proposed development.
Hence, it is proposed to utilise a series of on-site above ground detention tanks to mitigate the
stormwater runoff of the proposed development prior to discharging to the Lawful Point of
Discharge, northeast of the site.
Refer to Appendix E for the Rational Method Calculations, Appendix F for the Concept Site Levels
and Drainage Plans and Section 6 for the Stormwater Quality Management Plan.
5.2 Proposed Development Drainage
The proposed development drainage intent is as follows:
Development Catchment:
1. Runoff from the roof catchments will flow via downpipes to aboveground detention tanks
combined with rainwater reuse for mitigation prior to discharging to the lawful point of
discharge, northeast of the site.
2. Runoff from the ground catchment will be directed to the bioretention basin and level
spreader located in the north eastern corner of the site prior to discharging to the lawful
point of discharge, northeast of the site.
External Catchment:
1. Runoff from the external ground catchment, southwest of the site, will be collected by a
positive drainage system and directed to the lawful point of discharge, northeast of the
site.
Refer to Appendix F for the Concept Site Levels and Drainage Plans.
5.3 DRAINS Modelling Assessment
In order to ensure the proposed development will not discharge stormwater runoff greater than
pre-development flow rates, a detailed detention analysis was undertaken to determine what
detention mitigation is required for the proposed development to meet the requirements outlined
in Noosa Shire Council’s planning scheme policy. The IL-CL hydrological model has been used to
calculate the peak discharges from the site under the existing (pre-development) and proposed
(post development) conditions.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 10
23098 - SBSMP/4
Page 10
5.3.1 Hydraulic Model Parameters
The following parameters were obtained from the ARR DataHUB and have been adopted as part of
the DRAINS IL-CL hydrological modelling:
1. Impervious area initial loss (mm): 0mm
2. Impervious area continuing loss (mm/hr): 0mm
3. Pervious area initial loss (mm): 32mm
4. Pervious area continuing loss (mm/hr): 2.6mm
5.3.2 Design Storms
As defined in the NSC City Plan Policies and QUDM, the following design storms were adopted:
1. Minor Drainage System: 10 year ARI statistical flood (Q10 storm);
2. Major Drainage System: 100 year ARI statistical flood (Q100 storm).
5.3.3 Intensity Frequency Distribution
The BOM data and temporal patterns have been used for the DRAINS modelling and were obtained
for the following coordinates:
1. Latitude: -26.4181
2. Longitude: 152.9128
Refer to Appendix G for a copy of the BOM IFD data table.
5.3.4 Pre-Development Model
The pre-development catchment model utilises the following values in Table 5-4. The sub
catchment area taken into account for the pre-development catchment is 0.2275ha. Refer to
Figure 5.1 below for a screenshot of the pre-development model.
Table 5-4 – Pre-Development Catchment Characteristics for Catchment
Remaining
Effective Impervious Area Pervious Area
IL-CL Hydrological Model Impervious Area
(EIA) (PA)
(RIA)
Percentage of area (%) 0 8 92
Pre-Development
Catchment Time of Concentration
(mins)
5 2 9.7
Figure 5.1 – Pre-Development Model
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 11
23098 - SBSMP/4
Page 11
5.3.5 Post-Development Model
The post-development catchment model utilises the following values in Table 5-5. The sub
catchment area taken into account for the post-development catchment is 0.2275ha. Refer to
Figure 5.2 below for a screenshot of the pre-development model.
Table 5-5 – Post-Development Catchment Characteristics for Catchment
Effective Remaining
Pervious Area
IL-CL Hydrological Model Impervious Impervious Area
(PA)
Area (EIA) (RIA)
Post-Development
Percentage of area (%) 51 25 24
Catchment
Time of Concentration (mins) 5 5 5
Figure 5.2 – Post-Development Model
5.3.6 Post-Development Mitigated Model – On-site Detention Tank
The post-development mitigated catchment model utilises the following values in Table 5-6. The
sub catchment area taken into account for the post-development mitigated roof catchments are
0.0335ha, 0.0214ha, and 0.0258ha, respectively. The sub catchment area taken into account for
the post-development mitigated ground catchment bypassing to the lawful point of discharge is
0.0258ha.
Table 5-6 – Post-Development Mitigated Catchment Characteristics for Catchment
Remaining
Effective Impervious Area Pervious Area
IL-CL Hydrological Model Impervious
(EIA) (PA)
Area (RIA)
Post-Development Percentage of area (%) 100 0 0
Mitigated – Building
Time of Concentration
1 Catchment
(mins)
5 0 0
Post-Development Percentage of area (%) 100 0 0
Mitigated – Building
Time of Concentration
2 Catchment
(mins)
5 0 0
Post-Development Percentage of area (%) 100 0 0
Mitigated – Building
Time of Concentration
3 Catchment
(mins)
5 1 1
Post-Development Percentage of area (%) 0 56 44
Bypass Ground
Time of Concentration
Catchment
(mins)
0 5 5
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 12
23098 - SBSMP/4
Page 12
In order for the post-development stormwater discharge conditions to match the pre-development
conditions, it is proposed to incorporate 10kL above-ground rainwater tanks with a maximum
detention storage volume of 37.5kL. The combined detention/rainwater reuse tanks are to be
located adjacent to the proposed buildings.
The proposed OSD rainwater tanks will have the following properties:
Building 1, 2, & 3:
• Specified internal depth = 1.74m;
• Low flow orifice diameter = 0.028m;
• High flow orifice diameter = 0.140mm;
• Detention volume = 7.5kL; and
• Tank volume = 2x10kL (7.5kL detention + 2.5kL rainwater reuse) = 20kL
Building 2:
• Specified internal depth = 1.74m;
• Low flow orifice diameter = 0.028m;
• High flow orifice diameter = 0.140mm;
• Detention volume = 7.5kL; and
• Tank volume = 10kL (7.5kL detention + 2.5kL rainwater reuse)
Building 3:
• Specified internal depth = 1.74m;
• Low flow orifice diameter = 0.028m;
• High flow orifice diameter = 0.140mm;
• Detention volume = 7.5kL; and
• Tank volume = 2x10kL (7.5kL detention + 2.5kL rainwater reuse) = 20kL
The tanks will be designed to contain all roofwater flows up to a Q100 storm event and mitigate the
outflow at or less than pre-development flows. Stormwater runoff not conveyed to the detention
tanks will sheet flow across the development boundaries in conjunction with the mitigated flows
from the detention tanks at or less than pre-development.
Refer to Appendix F for the Concept Site Levels and Drainage Plan which details the proposed on-
site detention system and Figure 5.3 below for a screenshot of the post-development mitigated
model.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 13
23098 - SBSMP/4
Page 13
Figure 5.3 – Post-Development Mitigated Model
5.3.7 Comparison of Peak Flows at Lawful Point of Discharge
The pre-development and post-development mitigated peak flow rates were compared for the
catchment and are shown in Table 5-6 and Table 5-7 below.
Table 5-6 - Comparison of Peak Flows
Pre-Development Peak Flows Post-Development Peak Flows Post-Development Peak Flows
Property State (Un-Mitigated) (Un-Mitigated) (Mitigated)
(m3/s) (m3/s) (m3/s)
50% AEP
(m3/s)
0.035 0.055 0.034
20% AEP
(m3/s)
0.058 0.084 0.048
10% AEP
(m3/s)
0.065 0.094 0.056
5% AEP (m3/s) 0.084 0.110 0.064
2% AEP (m3/s) 0.102 0.135 0.089
1% AEP (m3/s) 0.115 0.155 0.087
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 14
23098 - SBSMP/4
Page 14
The DRAINS IL-CL hydraulic modelling results have demonstrated that the proposed mitigation
implemented will maintain pre-development flows (or less) for all design storms at the LPD located
north of the subject site.
To address the Water Quality and Drainage Code Performance Outcome PO2 design allowance for
climate change impacts, a 20% increase has been incorporated through the Climate change Rainfall
Multiplier function in the DRAINS program to address climate change considerations. This
adjustment is deemed to be an acceptable outcome to address AO2.4. The pre-development and
post-development mitigated with the 20% rainfall intensity increase peak flow rates were compared
for the catchment and are shown in Table 5-8 below.
Table 5-8 - Comparison of Peak Flows – Inclusion of 20% rainfall intensity increase
Pre-Development Peak Flows Post-Development Peak Flows (Mitigated) +
Property
(Un-Mitigated) 20% rainfall intensity increase
State
(m3/s) (m3/s)
50% AEP
(m3/s)
0.035 0.035
20% AEP
(m3/s)
0.058 0.050
10% AEP
(m3/s)
0.065 0.061
5% AEP
(m3/s)
0.084 0.078
2% AEP
(m3/s)
0.102 0.098
1% AEP
(m3/s)
0.115 0.109
The DRAINS IL-CL hydraulic modelling results with the additional 20% rainfall intensity increase have
demonstrated that the proposed mitigation will maintain pre-development flows (or less) for all
design storms at the LPD located north of the subject site.
Refer to Appendix H for the pre-development and post-development DRAINS results and Appendix
I for the post-development mitigated DRAINS results.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 15
23098 - SBSMP/4
Page 15
6 STORMWATER QUALITY
The following section of the report will outline the potential contaminants and proposed solutions
to be incorporated during the construction and operational phases of the proposed development.
6.1 State Planning Policy Assessment
The purpose of this sub section is to determine if State Planning Policy (SPP 2017) stormwater
quality requirements, as set out by the Department of Environment and Resource Management, will
be triggered for this development. Refer to Table 6-1 for the State Planning Policy Checklist for
stormwater quality.
Table 6-1 – State Planning Policy Checklist
Material Change of Use (MCU) Y/N?
MCU for an urban purpose that involves premises ≥ 2500m 2 N
AND
Will result in 6 or more dwellings
Y
OR
Will result in impervious area greater than 25% of the net developable area.
Y
The development has been assessed against the latest State Planning Policy 2017 (SPP 2017). The
proposed development will entail the material change of use for urban purposes, which will involve
a land less than 2,500m2. Consequently, State Planning Policy 2017 (SPP 2017) is not triggered.
However, in accordance with Performance Outcome PO6 outlined in the Water Quality and
Drainage Code (Noosa Plan 2020), all stormwater runoff is treated to achieve maximum removal
of nutrients, gross pollutants and suspended solids as determined by cost to efficiency ratios.
Hence, tertiary stormwater quality treatment is warranted for this development in accordance
with the requirements of Noosa Shire Council.
6.2 Construction Phase
Sediment generated during the construction phase shall be dealt with in accordance with an
Erosion and Sediment Control Plan and kept on site during the construction phase.
Erosion and Sediment Control (ESC) Measures such as silt fences, diversion drains, drainage
structure protection and dust control (clearing) will be implemented. Silt fences are to be erected
along the boundary of the site and around the construction area. These fences are to be cleaned
by the contractor when the capacity is reduced by 25%. Where possible, disturbance to the existing
surface is to be limited to the immediate work area. The existing ground cover is not to be stripped
until the contractor is ready for earthworks to begin.
Stockpiles and construction materials are not permitted to be stored within the road reserve and
should be contained using silt fences. Diversion drains are to be provided at upstream catchments
to reduce flows to earthworks areas. In any areas where flows could enter adjacent properties
temporary stabilisation is to be provided.
All ESC measures are to be provided as soon as earthworks have commenced and staged to suit
construction. The contractor is responsible for this action. A temporary construction exit is to be
located at each entry point to the site and will be determined based on the stage of works being
completed. The contractor is to ensure all dust tracked onto surrounding roads is immediately swept
to remove silt/dust.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 16
23098 - SBSMP/4
Page 16
All new stormwater pits are to be protected from sediment infiltration by wrapping new pits and
grates in geofabric or covering appropriately with timber board. Silt fences are to remain in place
during the maintenance period until the site is established (80% ground cover).
Potential sources of contaminants identified for the construction phase of the development are
outlined in Table 6-2 together with proposed stormwater quality improvement devices,
management and maintenance procedures.
Table 6-2 - Potential Contaminants and Proposed Treatments
Proposed Treatment
Management /
Pollutant Potential Source Device and Maintenance
Maintenance Procedures
Procedure
Sediment & Excavated material, fill Provision of sediment and Sand filled filter socks.
Eroded material, exposed silt barriers to the site Removal of excess
material ground, stockpiles of drainage entry and exit sand/silt build-up at
material. points. regular intervals and
after every storm.
Dust Stockpiles of material, Covering the material or Coverage of material
exposed ground. wetting it down at with plastic, geotextile,
regular intervals. surface binding agents or
regular watering.
Litter Refuse generated by Construction waste is to Industrial bin is to be
staff. be cleaned off the site provided within the
area and disposed of into construction area - to be
an industrial bin then emptied on at least a
removed by a refuse weekly basis.
collection contractor.
Concrete Washing of concrete Provision of a closed area Liquids to be removed by
trucks/tools to remove onsite for washing off of a waste collection
wet/unused concrete. concrete slurries. contractor. Solids to be
placed into a refuse bin.
Surfactants Washing down operations No cleaning of vehicles Monitoring & prevention
(detergents) on hardstand area using will be permitted on site.
detergents.
Chemical Typically this may occur Where spills occur, the A temporary containment
(Paints, due to spillage of containment area is to area. This is to be
thinners etc.) product. stop escape. The impermeable and of a
material is to be treated size to permit
(as required) and mixing/transfer, and
removed and cleaned by with a storage volume of
a licensed contractor. twice the largest
Minor spillage outside container used.
this area shall be cleaned Treatment of spills is to
up with cloths and occur on site. No
disposed of to waste via discharge of treated
the industrial bin. water to the stormwater
system is to occur
without council approval.
Incidents are to be
reported to the EPA.
Wastewater Spillage from the A licensed contractor No leakage is to be
relocation of the existing shall remove any residue permitted to enter the
sewerage reticulation. sewage from unused groundwater or discharge
pipes and contaminated to the stormwater
soils are to be disposed system.
of via the industrial bin.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 17
23098 - SBSMP/4
Page 17
6.3 Operational Phase
Water quality objectives (WQO’s) for South East Queensland as set out in State Planning Policy 2017
(SPP 2017) should be achieved by identifying and adopting best practise techniques in accordance
with the abovementioned guidelines. Refer to Table 6-3 for the target WQO’s.
Table 6-3 – Minimum Mean Annual Load Reductions
Minimum Mean Annual
Contaminant
Load Reductions
Total Suspended Solids (TSS) ≥ 80%
Total Phosphorus (TP) ≥ 60%
Total Nitrogen (TN) ≥ 45%
Gross Pollutants (GP) ≥ 90%
6.3.1 Sources of Contaminants
Potential sources of contaminants and stormwater quality improvement devices identified for the
operational phase of the development are outlined in Table 6-4.
Table 6-4 - Sources of Contaminants
Pollutant
Target Pollutant Type Acceptable Treatment Examples
Size
Primary Screening of gross Litter baskets, swales, buffer strips,
>5000um
Pollutants pollutants GPT’s, underground detention
Sedimentation of
Secondary 125um -
coarse to medium Swales, sedimentation basins, ponds
Pollutants 5000um
sediment
Underground detention, constructed
Enhanced
10um – wetland macrophyte zones, other bio
sedimentation of fine
125um technologies, proprietary tertiary
particulates
stormwater treatment dvices
Tertiary Adhesion and filtration Constructed wetland macrophyte zones,
0.45um –
Pollutants of very fine / colloidal other bio technologies, proprietary
10um
sediment tertiary stormwater treatment dvices
Biological uptake of Constructed wetland macrophyte zones,
<0.45um
dissolved particles other bio technologies
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 18
23098 - SBSMP/4
Page 18
6.3.2 Proposed Treatment Train
The proposed treatment train has been modelled using the following methodology:
Proposed Development Catchment
1. Roofwater from the proposed roof catchments will flow via downpipes to above ground
rainwater tanks for treatment with overflow to an internal drainage network.
2. Surface runoff from the proposed ground catchment will be directed to an end of line
bioretention basin for treatment, which is located in the north eastern corner of the site.
All runoff described above will then discharge to the legal point of discharge. The Concept Site
Levels and Drainage Plans of the proposed internal drainage network detailing the treatment train
assets are included in Appendix F. Refer to Table 6-5 for details of the proposed treatment train
assets.
Table 6-5 - Proposed Treatment Assets
Treatment Treatment
Description
Level Asset
Rainwater Reuse
Total of 12.5kL located adjacent to each proposed
Primary/ Tanks (Landscape
building, irrigating an area of 627m2 and servicing
Secondary Irrigation, Toilets
toilets and laundry for all units.
and Laundry)
Primary/ • 9m2 Total Filter Area
Secondary/ Bioretention Basin • 0.4m Filter Media Depth
Tertiary • 0.1m Extended Detention Depth
Refer to Appendix J for the Stormwater Quality Operational Management and Maintenance
Guidelines.
6.3.3 Pollutant Export Modelling
Following the definition of water quality objectives for the site and an assessment of the treatment
options suitable for the development, the most appropriate treatment scheme for the site was
identified. The impact of the stormwater management strategy on the quality of stormwater runoff
discharged from the site has been assessed using the pollutant export model, Model for Urban
Stormwater Improvement Conceptualisation (MUSIC).
6.3.4 MUSIC Modelling Parameters
The MUSIC model was set up in accordance with the Water-By-Design MUSIC Modelling Guidelines
for South East Queensland to the parameters listed in Table 6-6. Refer to Figure 6.1 for source
node areas in the proposed development area.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 19
23098 - SBSMP/4
Page 19
Table 6-6 – MUSIC Parameters
Parameter Data Used
Rainfall Data 40059 Cooroy Composite 1973 to 1983
Modelling Timestep 6 minutes
Routing No routing drain links were adopted
Table 6-7 – Catchment Runoff Generation Parameters
Parameter Residential Catchment
Rainfall Threshold 1
Soil Storage Capacity (mm) 18
Initial Storage Capacity (% capacity) 10
Field Capacity (mm) 80
Infiltration Capacity Coefficient a 243
Infiltration Capacity Coefficient b 0.6
Initial Depth (mm) 50
Daily Recharge Rate (%) 0
Daily Baseflow Rate (%) 31
Daily Deep Seepage Rate (%) 0
6.3.5 MUSIC Modelling Results
Refer to Figure 6.1 for a print screen schematic of the MUSIC model for the proposed development
and Figure 6.2 for the annual pollutant loads that will be discharged from the site for the proposed
development.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 20
23098 - SBSMP/4
Page 20
Figure 6.1 - MUSIC Model Print Screen Schematic
Figure 6.2 - MUSIC Modelling Results
The modelling results show that the pollutant reduction objectives are met for all contaminants
given in Section 6.
Should operational requirements change, this plan is required to be amended to suit. Substantial
changes may require resubmission to the local authority. Following completion of construction, this
plan is to be incorporated into the total-site management practices.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 21
23098 - SBSMP/4
Page 21
7 FLOODING
Information from the Noosa Shire Council Flood Hazard Overlay Map confirms that the site is
unaffected by flooding and inundation. As the subject site and proposed infrastructure is not in a
tidal/flood risk area, it is expected that the 800mm to allow for sea level rise is irrelevant in this
instance.
Refer to Appendix K for the NSC Flood Planning Control Property Report.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 22
23098 - SBSMP/4
Page 22
8 CONCLUSION
The Proposed Townhouse Development at 5 Pearl Street, Cooroy has been assessed for its impact
on the quantity and quality of stormwater drainage.
The lawful point of discharge is the existing Environmental Management and Conservation Area,
northeast of the site.
On-site detention (OSD) is warranted for the proposed development. The Water Quality and
Drainage Code Performance Outcome PO2 design allowance for climate change impacts has also
been addressed.
Sediment generated during the construction phase shall be dealt with in accordance with an
Erosion and Sediment Control Plan to be kept on site during the construction phase.
The proposed development requires tertiary stormwater quality treatment in accordance with the
requirements of Noosa Shire Council. Rainwater reuse and bioretention end-of-line treatment will
be incorporated into the proposed development to meet the prescribed water quality objectives.
The subject site is unaffected by flooding.
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 23
23098 - SBSMP/4
Page 23
APPENDIX A
DETAILED SITE SURVEY
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 24
Skyline Surveyors
Suite 11C
Brightwater Corporate Centre PHONE
07 5493 4877
69 Attenuata Drive
MOUNTAIN CREEK QLD 4557
E: [email protected]
W: www.skysurv.com.au
Page 25
23098 - SBSMP/4
Page 24
APPENDIX B
PROPOSED DEVELOPMENT PLANS
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 26
& & & § & & & § £
z 2 8 am © arte VAN 3 8 é 8 Ln
v oF T
r 5 = 7 , FT
‘ ‘ : . ' ! f S
q Do i : ' NON SETRACK
: Q 4 ae —Tt tam? .
We H 109m! H nA ! na oo J oon TERRACE 1 *y
\ 5 : \ i ' Wo Wo
\ a a ios po.) 00 fe som PE ed eae
rN % tI
g ;
FB ——
" wn in
. 3 7
“Ts aWT s hot | |
\ KITCHEN,
fy , LY see, oh —
K 1/8 IY 7 BE =a i.
\ ‘| . . ; [Lov LY | 33
uw = is i. ag. |e Hy *\ KITCHEN S| KITCHEN KITCHEN OF i al TF] Ok
ies gt * | EN Pes TEI ES It, a
jé @ H ud J by = \
be Q \ wNA GARAGE ‘ GARAGE BaRAGE ) GARAGE | Ba GARAGE ‘
(A = ir b ‘U0 uo2 uo3 ‘U04 u05 uos. |E U07 U08 ~
me = fe ‘. TYPEO1 TYPE02 TYPEO2 "TYPEO2 TYPEO2 TYPEO2, TYPEO2 TYPE03
5 Exe GARAGE i ‘| '
sal | 4
= \ | :
4 :
om ‘ J ‘ it
| te |v : 108.4m
| mc? Pj NE EES] ST ee ie
I 100» 2500 _|soap *y. \ ee 1120 1000)
! yy un . *, BUILDING 01 . ' 1 7-~--_ |: BUILDING 02 ~~ -----_
| \ Ope Ts 6520 12506 5270 S250 ey S770 s 250y ye S770 250) S770 Oye u ye 270 250 jy¢[ > ~ ~ 527 2506 6520 oye ~ PF -|
| ! . a tf bf —y 4 oF a a + ee Ht
| f z, +4— “ 7 28780 , # 5180 — oe n 17740 == — ~~ SEWER = +
| s- gy ig . \ . ad’ ‘ g OTT gael Tape
& | . 7 3 ‘ + 5 . #1 sto tase ra =
= : : | soy. S200 py 5210 2s0py sz Opp rr = sy 2 .
; : / ! +e} et oF 34 IIs
\ —+——————_4 fo : BUILDING 03... | * sg
‘ : /| | ‘ |
x ; Ty) g
€ € aT 7om € TeDOr ' QT § & | 7 8
5 5 s 3 3 3 | J aw
| 4
tek
106.2m | me
| +e
| HoT
| 105.6m
|
g |
| u09 U10 .
yl TYPEO2 TYPE02 U12
gl GARAGE GARAGE TYPEQ2 TYPE02
4 a 3 g Eo GARAGE GARAGE cf
" KITCHEN q 4
|
106.4 DEVELOPMENT,
nen \ oe
; Feerace | :
Ww TMBER x Bhfenrace [1 150m *
ere 6.6m od wssm ' ALTUM
BLOCK BALUSTERS. /
fi
1
—— os 1 FLOOR PLAN - LEVEL 1
4000 SETBACK ~~ . /
° H \ \ !
ERMINATES INTO 1800 o ' . ‘ : Development Approval
Fi ‘ aN A . / north scale: 1:100 @A1
ws - 1x 1100L RECYCLING ‘ SN / scale: 1:200 @A3
= 1x 1100L GENERAL WASTE ec ee ‘ ' issue: 05
date: 13-03-24
7283-DA04
__Project Number
TREE
” BUCKBURNEJICKSON
01 FLOOR PLAN LEVEL 1
1:100 Trees
ARCHITECTURE | LANDSCAPE | INTERIOR | PROJECT MANAGEMENT
inte property a Blackbure Jackson Design Py
Page 27
23098 - SBSMP/4
Page 25
APPENDIX C
NSC INTERACTIVE MAPPING PLANS
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 28
Noosa Shire Council does not warrant the accuracy of information in this publication and any person using or relying upon such information does so on the basis that Noosa Shire Council shall bear no responsibility or liability 20/09/2023
Page 29
23098 - SBSMP/4
Page 26
APPENDIX D
NSC WATER QUALITY AND DRAINAGE CODE
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 30
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
Stormwater Drainage Design
PO1 AO1 RO1
The development and its stormwater A stormwater management plan is prepared The proposal complies. Refer to the
management system is planned and consistent with PSP6 Engineering Design Site Based Stormwater Management
designed having regard to: Standards - Roads, drainage and earthworks. Plan (SBSMP) report prepared by
(a) the natural features of the site; MCE.
(b) the need to avoid impacts and potential
risks to ecologically important areas;
(c) the likely effectiveness of erosion and
sediment control and stormwater ✓
drainage measures during rainfall
events during and post construction;
and
(d) the need to protect environmental
values and water quality of receiving
waters both during and post
construction
PO2 AO2.1 RO2.1
Stormwater drainage infrastructure is Stormwater drainage planning, design and The proposal complies. All stormwater
planned, designed and construction is in accordance with PSP6 design will comply with the PSP6
Engineering Design Standards –
constructed to:
(a) incorporate allowance for increased
Engineering Design Standards - Roads,
drainage and earthworks and the latest version
✓ Roads, drainage and earthworks and
flood risk and tidal inundation through of the Queensland Urban Drainage Design the latest version of the Queensland
pipework as a result of cilmate change Manual. Urban Drainage Design Manual.
and sea level rise; AO2.2 RO2.2
(b) ensure the development is adequately The stormwater drainage system connects to a Refer to the SBSMP prepared by
drained; and lawful point of discharge in accordance with ✓ MCE for the lawful point of discharge.
(c) ensure stormwater is managed and PSP6 Engineering Design Standards - Roads,
lawfully discharged without altering drainage and earthworks
stormwater drainage characteristics AO2.3 RO2.3
external to the site. Stormwater flows discharging from the The proposal complies. Above ground
development are demonstrated to be ✓ detention tanks will be utilised to
consistent with pre-development mitigate flows prior to discharge to the
characteristics. legal point of discharge. Refer to the
SBSMP prepared by MCE.
1
Solution: ✓ Acceptable Solution Page 1 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 31
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
AO2.4 RO2.4
Development provides for the management of The proposal complies. The
stormwater to incorporate appropriate development provides for the
allowance for climate change impacts
(including rainfall intensity and sea level rise),
✓ management of stormwater to
incorporate appropriate allowance for
in accordance with PSP6 Engineering Design climate change impacts in accordance
Standards – Roads, Drainage and Earthworks. with PSP6. Refer to the SBSMP
prepared by MCE.
PO3 AO3.1
Stormwater drainage infrastructure conveys Stormwater drainage infrastructure meets the
run-off in a manner that allows roads to desired standards of service for roads
deliver desired standards of service functionality set out in PSP6 Engineering N/A
appropriate to the local conditions and local Design Standards - Roads, Drainage and
stormwater drainage characteristics. Earthworks.
PO4 AO4.1 RO4.1
Stormwater infrastructure is compatible with The location, design and construction of Refer to RO2.1.
existing infrastructure, allows for easy stormwater drainage structures is in
access for the ongoing maintenance by
Council, is cost effective across its design
accordance with PSP6 Engineering Design
Standards - Roads, drainage and earthworks.
✓
life
AO4.2
Where infrastructure is located on private land
an easement is dedicated over the
infrastructure in accordance with PSP6 N/A
Engineering Design Standards - Roads,
drainage and earthworks.
AO4.3 RO4.3
Any alterations or repairs to infrastructure as a The proposal complies.
result of the development are made at no cost ✓
to Council.
AO4.4 RO4.4
Development avoids stormwater inflow and The proposal complies. Stormwater
infiltration to the sewer infrastructure network. ✓ will be designed to avoid inflow and
infiltration into the sewer infrastructure
network.
1
Solution: ✓ Acceptable Solution Page 2 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 32
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
AO4.5 RO4.5
Stormwater infrastructure is designed to The proposal complies.
minimise maintenance costs and the ✓
requirement for specialized equipment for
maintenance techniques.
PO5 AO5.1
Stormwater drainage infrastructure is Stormwater drainage infrastructure avoids
aligned to avoid crossing waterways, crossing waterways, wetlands drainage lines N/A
wetlands, drainage lines and ecological and ecologically important areas or follows the
important areas, or where it is demonstrated edge of existing disturbed areas.
this is unavoidable, disturbed areas are AO5.2
reinstated and revegetated upon completion Stormwater drainage infrastructure avoids
of works. crossing waterways, wetlands drainage lines N/A
and ecologically important areas or follows the
edge of existing disturbed areas.
AO5.3
Temporary vehicular crossings of waterways
must be designed and constructed to be N/A
consistent with the current International
Erosion Control Association Best Practice
Book Series.
Stormwater quality and protection of receiving waters
PO6 AO6.1 RO6.1
Development is located, designed, Stormwater runoff discharging into High The proposal complies.
constructed and operated to protect and Ecological Value waters as a result of
enhance environmental values and water
quality of waterways, wetlands, lakes,
development causes no increase in gross
pollutants, total suspended solids, total
✓
ground waters and drainage systems. phosphorous or total nitrogen compared to
a pre-development scenario.
Editor’s note: Environmental values of
waters and water quality objectives are AND
prescribed in Schedule 1 of the AO6.2 RO6.2
Environmental Protection (Water) Policy All stormwater runoff is treated to achieve The proposal complies. A bio-
2009 and are identified on the State maximum removal of nutrients, gross retention system will be incorporated
Planning Policy Interactive Mapping System pollutants and suspended solids as determined into the drainage design to achieve
1
Solution: ✓ Acceptable Solution Page 3 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 33
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
by cost to efficiency ratios. (e.g. bioretention the target pollutant reduction loads.
basins must be sized to Refer to the SBSMP prepared by
achieve at least 80% reduction in total MCE.
suspended solids, 60% reduction in total
phosphorous, 45% reduction in total nitrogen
✓
and 90% reduction in gross pollutants >5mm)
OR
AO6.3
Developments achieve a minimum 3 drop
rating consistent with the Water by Design
Living Waterways Scoring Guide (Healthy
Land and Water).
Editor’s note— PSP6 Engineering Design N/A
Standards - Roads, Drainage and Earthworks
provides guidance on stormwater design and
modelling requirements
PO7 AO7.1 RO7.1
Water quality treatment systems use natural Water quality treatment systems are designed The proposal complies.
processes and to be integrated into the landscape consistent
materials, whenever possible, and are with the technical design guideline published
integrated into development by Healthy Land and Water Water by Design
to enhance biodiversity and landscape for the ✓
benefits feature. (eg. For Bioretention Basins:
Bioretention Technical Design Guidelines
(October 2014) and for Wetland Systems the
Wetland Technical Design Guideline (May
2017).
PO8 AO8.1
Water quality treatment infrastructure to be Detailed life cycle costing is provided for the
N/A
dedicated as public assets are proven to be entire treatment train system including
suitable for its use and of a cost replacement costs of asset parts.
effective and efficient standard AO8.2
Treatment systems dedicated as public assets
1
Solution: ✓ Acceptable Solution Page 4 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 34
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
are designed to minimise maintenance,
renewal and adaption costs and the
N/A
requirement for specialised equipment,
material or maintenance
techniques.
AO8.3
Vegetated stormwater management systems
to be dedicated as public assets are
established and maintained during the
maintenance period to ensure optimal N/A
vegetated growth and that the functional
elements of the system achieve the design
function at the end of the maintenance period.
PO9 AO9.1 RO9.1
Treatment systems are designed to Free draining inlets and outlets are provided to The proposal complies. The proposal
eliminate or minimise health, safety and ensure that waters do not pond for more than ✓ stormwater treatment system will be
aesthetic hazards, including risks associated 24 hours. designed to be free draining.
with insect breeding, odour and public AO9.2 RO9.2
safety. Developments are designed to eliminate The proposal complies. Retaining
retaining walls in excess of 0.8m for any water ✓ walls do not exceed 0.8m.
quality treatment device.
Hydraulic and Waterway Stability
PO10 AO10 RO10
Development prevents increased bed and The development is designed to: The proposal complies. Refer to the
bank erosion and (a) limit the peak 1 year ARI event discharge SBSMP prepared by MCE.
sedimentation in receiving waterways by within the receiving waterway to the pre-
avoiding changes in low development peak 1 year discharge;
rate, peak flow run-off and flow duration. (b) maximise pervious areas by using
pervious alternatives for otherwise
impervious areas wherever possible;
(c) provide for capture and reuse of
stormwater for non-potable purposes for
gardening, toilet flushing, laundry and hot
water supply uses; ✓
(d) incorporate appropriate detention features;
1
Solution: ✓ Acceptable Solution Page 5 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 35
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
and
(e) incorporate natural channel design
principles.
Editor’s note: The Sustainable Building
Design Code includes requirements for
stormwater capture and reuse.
PO11 AO11.1
Water sensitive urban design principles are The design and construction of a natural
applied to achieve multifunctional design of channel or natural channel rehabilitation works
waterways, wetlands and drainage lines that are in accordance with the Natural Channel N/A
provide for: Design Guidelines (Brisbane City Council)
(a) stormwater conveyance that uses having regard to local topography, geology and
natural channel design; geomorphology.
(b) protection of landscape features and AO11.2
ecological important areas including Landscape features, plant species and habitat
terrestrial and aquatic habitat; types used in stormwater conveyance N/A
(c) aesthetic and passive recreation channels are complementary to the local
values; context and natural waterways
(d) flood management and conveyance of AO11.3
external catchment stormwater through Bank and bed stability and planting densities
the development; result in a stable channel over the long term N/A
(e) landscaping that incorporates local and minimal potential for pest plant species.
native species; and
AO11.4
(f) bed and bank stability
Water Sensitive Design measures are
incorporated into the development, as detailed
in the document Water Sensitive Designs
small improvements, new ideas, concepts and N/A
sketch designs for stormwater filtration
systems (Healthy Waterways Water by
Design).
AO11.5
Floodplain management is designed in
accordance with the Framework for the
Integration of Flood and Stormwater N/A
Management into Open Space published by
1
Solution: ✓ Acceptable Solution Page 6 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 36
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
Healthy Waterways Water by Design (version
current at the time of development
application).
PO12 AO12.1
Development protects in-stream ecology by Where run-off from or within the site passes
maintaining pre development low flow through or drains to natural channels,
discharge regimes and maintaining fish waterways or wetlands, development protects
passages. in steam ecology by maintaining pre-
development low flow discharge regimes in N/A
accordance with the frequent flow
management objectives in PSP6 Engineering
Design Standards - Roads, drainage and
earthworks
AO12.2
Instream structures such as roads, bridges,
culverts, and other stormwater infrastructure N/A
do not cause barriers to fish passage and
facilitate the movement of terrestrial and
aquatic fauna along waterway corridors
AO12.3
Benthic substrate retains a continuous grade
with the direction of flow consistent with the N/A
natural bed profile.
PO13 AO13.1
Development is designed and constructed to The location and form of stormwater discharge
maintain surface and ground water balances points do not alter the pre-development N/A
that sustain the environmental values of hydrology of receiving surface water or
water dependent ecosystems, including groundwater.
downstream aquatic, riparian, wetland and AO13.2
terrestrial ecosystems. Developments located on groundwater
recharge or discharge areas are designed and
managed in accordance with a groundwater
recharge and discharge management plan
prepared by a suitably
experienced and qualified groundwater
hydrologist. The groundwater recharge or
1
Solution: ✓ Acceptable Solution Page 7 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 37
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
discharge must demonstrate that the N/A
development does not affect groundwater
balances beyond the property boundaries
Editor's Note— PSP6 Engineering Design
Standards - Roads, drainage and earthworks
provides guidance on prepare a groundwater
recharge and discharge plan.
Construction and establishment of stormwater management systems
PO14 AO14.1 RO14.1
Construction methods provide for An erosion and sediment control plan prepared An Erosion and Sedimentation Control
appropriate controls to avoid entry and in accordance with the International Erosion Plan shall be prepared (prior to
transport of litter, sediment, and associated Control Association Best Practice Books commencement of construction) and
prescribed water contaminants into receiving demonstrates that the capture and release of maintained for the management of the
waters. stormwater achieves the design objectives sediment laden stormwater during the
listed in Table A: Construction phase – construction phase in accordance with
Editor's note— Water contaminants are stormwater management design objectives IECAs Best Practice guidelines.
prescribed in the of the State Planning Policy (Appendix 2). ✓
Environmental Protection Act 1994
Editor’s note— PSP6 Engineering Design
Standards - Roads, drainage and earthworks
provides guidance on requirements for
preparing an Erosion Management Plan.
AO14.2 RO14.2
Construction works are designed and Unnecessary disturbance to soil shall
managed to restrict the extent of clearing and be avoided and soil surfaces shall
soil exposure to the minimum necessary for
access, and safe construction at any one time
✓ remain stabilized.
AO14.3 RO14.3
For buildings: The proposal complies. Refer to
(a) upstream runoff is diverted around the RO14.1.
construction site;
(b) sediment barriers are provided downslope
of disturbed areas to prevent sediment
washing into gutters, drains and
1
Solution: ✓ Acceptable Solution Page 8 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 38
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
waterways , wetlands or drainage lines
either on or off the site; and
(c) temporary or permanent downpipes are ✓
connected to the stormwater system
before laying the roof; or
(d) localised erosion is avoided by directing
flow from downpipes over non-erosive
areas.
AO14.4 RO14.4
Chemical flocculants used as part of an The proposal complies. Refer to
erosion and sediment control plan do not harm ✓ RO14.1.
the environmental values within receiving
waters.
AO14.5 RO14.4
Appropriately sized litter containment areas, The proposal complies. Refer to
with provision for sorting recyclables are ✓ RO14.1.
provided for the type of litter expected to be
generated onsite.
Wastewater management and effluent disposal
PO15 AO15
Development does not discharge Wastewater (non-sewage) generated from the
wastewater unless it can be demonstrated to development is collected and contained on-
not compromise environmental values of site, and is;
waters and water quality objectives. (a) lawfully disposed to sewer; or
(b) transferred off-site for treatment/disposal
Editor’s Note—Environmental values of to an appropriately
waters and water quality objectives are licenced facility;
prescribed in Schedule 1 of the (c) reused on-site in a closed-cycle irrigation
Environmental Protection (Water) Policy scheme, industrial processes, washing or
2009. cleaning or other purpose; or N/A
(d) treated to meet the drinking water supply
environmental values prior to release.
Editor’s Note—The Plumbing and Drainage
Act 2003 sets out requirements for wastewater
1
Solution: ✓ Acceptable Solution Page 9 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 39
Water Quality and Drainage Code
Noosa Council Plan July 2020
Performance and Acceptable Outcomes Table
Version: 2020
Performance Outcomes Acceptable Outcomes Solution1 Comments Council Use
management.
PO16 AO16
On-site effluent treatment and disposal An onsite effluent system and disposal area is:
systems are designed, constructed and (a) not located on a slope greater than 1 in
managed to not compromise the (10%);
environmental values of waters and water (b) not located at or below the 1% annual
quality objectives. exceedance probability (AEP flood event);
(c) not located within a riparian buffer area
mapped on a Biodiversity, Waterways and
Wetlands Overlay Map; and
(d) setback 400 metres minimum from the full
supply level of Lake Macdonald.
Editor’s Note—The Plumbing and Drainage
Act 2003 sets out requirements for on-site N/A
effluent treatment and disposal. The
Queensland Plumbing and Wastewater Code
and associated
guidelines are used to confirm the suitability of
each site to accommodate an on-site
sewerage facility; or where a centrally located
group collection treatment system is proposed,
confirmation as to the suitability of the
designated site to accommodate the onsite
sewerage facility. Additionally, where the
combined total peak design capacity of effluent
treatment is less than 21 equivalent persons,
the design of the system achieves a low to
medium risk classification in accordance with
Seqwater’s Land Use Risk Tool for onsite
sewerage facilities
1
Solution: ✓ Acceptable Solution Page 10 of 10
A/S Alternative Solution \\mcedc01\DATA\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\NSC Water Quality and Drainage Code 2020.docx
N/A Not applicable to this proposal Job: 23098
Rev: 1
Site Address: 5 Pearl Street, Cooroy 18/03/2024
Page 40
23098 - SBSMP/4
Page 27
APPENDIX E
RATIONAL METHOD CALCULATIONS
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 41
Rational Method Peak Flow Calculations
Job No: 23098 MORGAN CONSULTING
Job Type: Proposed Townhouse Development ENGINEERS PTY LTD
Address: 5 Pearl Street, Cooroy 1 GREAT GEORGE STREET
Council: NSC PADDINGTON QLD 4064
IFD Data: 26.4125 (S),152.9125 (E) Minor Storm: Q10 Designed: WB
1
I10 70mm/hr Major Storm: Q100 Checked: HM
Pre Development Post Development
Time of Concentration
Standard Inlet Time Standard Inlet Time
Standard Inlet Time mins Standard Inlet Time 5 mins
Sheet Flow (Friends Equation) Sheet Flow (Friends Equation)
Sheet flow length (L) 57 m Sheet flow length (L) m
roughness (n) 0.03 short grass roughness (n) 0.014 Concrete
Fall of NSL 1.89 m Fall of NSL 0.29 m
Slope of Surface (S) 3.3 % Slope of Surface (S) %
total 9.7 mins total 0.0 mins
Concentrated Overland Flow Concentrated Overland Flow
Flow distance 0 m Flow distance m
velocity 0.7 m/s velocity 0.7 m/s
mins 0.0 mins mins 0.0 mins
Surface type multiplier 3.0 Surface type multiplier 4.0
total 0.0 mins total 0.0 mins
Total tc 9.7 mins Total tc 5.0 mins
Runoff Volume Calculations
Name Area (ha) tc fi C10 Name Area (ha) tc fi C10
0.228 0.27 0.75 0.228 0.76 0.85
Total 0.228 9.7 0.75 Total 0.228 5.0 0.85
Frequency Frequency
ARI Cy Iy Qy ARI Cy Iy Qy
Factor A (Ha) Factor A (Ha)
(years) (Fy*C10) (mm/h) (m3/s) (years) (Fy*C10) (mm/h) (m3/s)
(Fy) (Fy)
3 mth 0.019 3 mth 0.026
1 0.800 0.603 99 0.228 0.038 1 0.800 0.682 120 0.228 0.052
2 0.850 0.641 111 0.228 0.045 2 0.850 0.724 135 0.228 0.062
5 0.950 0.716 150 0.228 0.068 5 0.950 0.809 183 0.228 0.094
10 1.000 0.754 174 0.228 0.083 10 1.000 0.852 215 0.228 0.116
20 1.050 0.792 199 0.228 0.099 20 1.050 0.895 245 0.228 0.139
50 1.150 0.867 228 0.228 0.125 50 1.150 0.980 285 0.228 0.176
100 1.200 0.905 251 0.228 0.143 100 1.200 1.000 315 0.228 0.199
Page 1 of 1 14/05/2024
Page 42
23098 - SBSMP/4
Page 28
APPENDIX F
CONCEPT SITE LEVELS AND DRAINAGE PLAN
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 43
P: (07) 3369 8411
F: (07) 3369 1893
E : [email protected]
© Morgan Consulting Engineers
This drawing is not to be copied,
reta ined o r used wi tho ut the
permission of the copyright holder.
1 GREAT GEORGE STREET
PADDINGTON Q LD 4 0 6 4
Page 44
23098 - SBSMP/4
Page 29
Appendix G
BOM IFD
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 45
Copyright Commonwealth of Australia 2016 Bureau of Meteorology (ABN 92 637 533 532) IFD Design Rainfall Intensity (mm/h) 29-Aug-23 Issued: Location La5 Pearl Stre Cooroy Requested Latitude Nearest gri Latitude Duration 1 min 2 min 3 min 4 min 5 min 10 min 15 min 20 min 25 min 30 min 45 min 1 hour 1.5 hour 2 hour 3 hour 4.5 hour 6 hour 9 hour 12 hour 18 hour 24 hour 30 hour 36 hour 48 hour 72 hour 96 hour 120 hour 144 hour 168 hour Duration in UO BWN PR 10 15 20 25 30 45 60 90 120 180 270 360 540 720 1080 1440 1800 2160 2880 4320 5760 7200 8640 10080 63.20% 165 141 132 126 120 97.3 82.3 71.8 64 58 46 38.7 30.2 25.3 19.8 15.4 13 10.2 8.54 6.63 5.51 4.75 4.19 3.42 2.53 2.04 1.71 1.49 1.33 -26.4181 Longitude 26.4125 (S)Longitude 152.9125 (E) 50% 186 159 149 142 135 110 92.9 81 72.2 65.4 51.9 43.8 34.3 28.8 22.6 17.7 15 11.8 9.95 7.78 6.48 5.6 4.95 4.04 2.99 2.4 2.02 1.75 1.56 152.9128 Annual Exceedance Probability (AEP) 20% 250 216 203 192 183 148 125 109 97.1 88.1 70.3 59.5 47 39.8 31.5 25.1 21.4 17.1 14.6 11.5 9.7 8.43 7.48 6.15 4.58 3.67 3.08 2.66 2.35 10% 293 256 239 226 215 172 145 127 113 103 82.6 70.2 55.8 47.4 37.8 30.3 26 20.9 17.9 14.2 12 10.5 9.35 7.72 5.78 4.64 3.89 3.36 2.97 5% 333 295 275 259 245 196 165 144 129 117 94.5 80.7 64.4 55 44.1 35.5 30.5 24.7 21.2 17 14.4 12.6 11.3 9.37 7.06 5.69 4.78 4.12 3.63 2% 385 348 323 303 285 225 190 166 149 136 110 94.5 76.1 65.3 52.7 42.7 36.8 29.9 25.8 20.8 17.7 15.6 14 11.7 8.86 7.17 6.02 5.19 4.55 1% 424 390 360 336 315 247 208 182 164 150 122 105 85.1 73.3 59.4 48.3 41.8 34 29.4 23.8 20.4 18 16.2 13.6 10.4 8.41 7.06 6.08 5.32
Page 46
23098 - SBSMP/4
Page 30
Appendix H
DRAINS PRE & POST DEVELOPMENT RESULTS
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 47
DRAINS results prepared from Version 2023.11.8718.30178 DRAINS results prepared from Version 2023.11.8718.30178
PIT / NODE DETAILS Version 8 PIT / NODE DETAILS Version 8
Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint
HGL Flow Arriving Volume Freeboard (cu.m/s) HGL Flow Arriving Volume Freeboard (cu.m/s)
(cu.m/s) (cu.m) (m) (cu.m/s) (cu.m) (m)
SUB-CATCHMENT DETAILS SUB-CATCHMENT DETAILS
Name Max EIA Remaining EIA RIA PA Due to Storm Name Max EIA Remaining EIA RIA PA Due to Storm
Flow Q Max Q Max Q Tc Tc Tc Flow Q Max Q Max Q Tc Tc Tc
(cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min) (cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min)
Pre-Dev 0.035 0 0.035 5 2 9.7 50% AEP, 1.5 hour burst, Storm 1 Pre-Dev 0.084 0 0.084 5 2 9.7 5% AEP, 30 min burst, Storm 8
Post-Dev 0.055 0.029 0.026 5 5 5 50% AEP, 30 min burst, Storm 9 Post-Dev 0.11 0.064 0.053 5 5 5 5% AEP, 10 min burst, Storm 6
PIPE DETAILS PIPE DETAILS
Name Max Q Max V Max U/S Max D/S Due to Storm Name Max Q Max V Max U/S Max D/S Due to Storm
(cu.m/s) (m/s) HGL (m) HGL (m) (cu.m/s) (m/s) HGL (m) HGL (m)
CHANNEL DETAILS CHANNEL DETAILS
Name Max Q Max V Due to Storm Name Max Q Max V Due to Storm
(cu.m/s) (m/s) (cu.m/s) (m/s)
DETENTION BASIN DETAILS DETENTION BASIN DETAILS
Name Max WL MaxVol Max Q Max Q Max Q Name Max WL MaxVol Max Q Max Q Max Q
Total Low Level High Level Total Low Level High Level
Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results) Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results)
{\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results).drn - DRAINS run at 16:46:07 on 14/5/2024 using Watercom Drains v2023.11.8718.30178 {\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results).drn - DRAINS run at 16:47:01 on 14/5/2024 using Watercom Drains v2023.11.8718.30178
DRAINS results prepared from Version 2023.11.8718.30178 DRAINS results prepared from Version 2023.11.8718.30178
PIT / NODE DETAILS Version 8 PIT / NODE DETAILS Version 8
Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint
HGL Flow Arriving Volume Freeboard (cu.m/s) HGL Flow Arriving Volume Freeboard (cu.m/s)
(cu.m/s) (cu.m) (m) (cu.m/s) (cu.m) (m)
SUB-CATCHMENT DETAILS SUB-CATCHMENT DETAILS
Name Max EIA Remaining EIA RIA PA Due to Storm Name Max EIA Remaining EIA RIA PA Due to Storm
Flow Q Max Q Max Q Tc Tc Tc Flow Q Max Q Max Q Tc Tc Tc
(cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min) (cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min)
Pre-Dev 0.058 0 0.058 5 2 9.7 20% AEP, 1.5 hour burst, Storm 2 Pre-Dev 0.102 0 0.102 5 2 9.7 2% AEP, 25 min burst, Storm 4
Post-Dev 0.084 0.045 0.039 5 5 5 20% AEP, 30 min burst, Storm 10 Post-Dev 0.135 0.073 0.066 5 5 5 2% AEP, 10 min burst, Storm 7
PIPE DETAILS PIPE DETAILS
Name Max Q Max V Max U/S Max D/S Due to Storm Name Max Q Max V Max U/S Max D/S Due to Storm
(cu.m/s) (m/s) HGL (m) HGL (m) (cu.m/s) (m/s) HGL (m) HGL (m)
CHANNEL DETAILS CHANNEL DETAILS
Name Max Q Max V Due to Storm Name Max Q Max V Due to Storm
(cu.m/s) (m/s) (cu.m/s) (m/s)
DETENTION BASIN DETAILS DETENTION BASIN DETAILS
Name Max WL MaxVol Max Q Max Q Max Q Name Max WL MaxVol Max Q Max Q Max Q
Total Low Level High Level Total Low Level High Level
Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results) Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results)
{\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results).drn - DRAINS run at 16:46:15 on 14/5/2024 using Watercom Drains v2023.11.8718.30178 {\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results).drn - DRAINS run at 16:48:06 on 14/5/2024 using Watercom Drains v2023.11.8718.30178
DRAINS results prepared from Version 2023.11.8718.30178 DRAINS results prepared from Version 2023.11.8718.30178
PIT / NODE DETAILS Version 8 PIT / NODE DETAILS Version 8
Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint
HGL Flow Arriving Volume Freeboard (cu.m/s) HGL Flow Arriving Volume Freeboard (cu.m/s)
(cu.m/s) (cu.m) (m) (cu.m/s) (cu.m) (m)
SUB-CATCHMENT DETAILS SUB-CATCHMENT DETAILS
Name Max EIA Remaining EIA RIA PA Due to Storm Name Max EIA Remaining EIA RIA PA Due to Storm
Flow Q Max Q Max Q Tc Tc Tc Flow Q Max Q Max Q Tc Tc Tc
(cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min) (cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min)
Pre-Dev 0.065 0 0.065 5 2 9.7 10% AEP, 25 min burst, Storm 8 Pre-Dev 0.115 0 0.115 5 2 9.7 1% AEP, 25 min burst, Storm 4
Post-Dev 0.094 0.049 0.045 5 5 5 10% AEP, 15 min burst, Storm 5 Post-Dev 0.155 0.08 0.075 5 5 5 1% AEP, 10 min burst, Storm 7
PIPE DETAILS PIPE DETAILS
Name Max Q Max V Max U/S Max D/S Due to Storm Name Max Q Max V Max U/S Max D/S Due to Storm
(cu.m/s) (m/s) HGL (m) HGL (m) (cu.m/s) (m/s) HGL (m) HGL (m)
CHANNEL DETAILS CHANNEL DETAILS
Name Max Q Max V Due to Storm Name Max Q Max V Due to Storm
(cu.m/s) (m/s) (cu.m/s) (m/s)
DETENTION BASIN DETAILS DETENTION BASIN DETAILS
Name Max WL MaxVol Max Q Max Q Max Q Name Max WL MaxVol Max Q Max Q Max Q
Total Low Level High Level Total Low Level High Level
Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results) Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results)
{\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results).drn - DRAINS run at 16:46:45 on 14/5/2024 using Watercom Drains v2023.11.8718.30178 {\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Pre-Post ONLY (results).drn - DRAINS run at 16:48:22 on 14/5/2024 using Watercom Drains v2023.11.8718.30178
Page 48
23098 - SBSMP/4
Page 31
Appendix I
DRAINS POST DEVELOPMENT MITIGATED RESULTS
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 49
DRAINS results prepared from Version 2023.11.8718.30178 DRAINS results prepared from Version 2023.11.8718.30178
PIT / NODE DETAILS Version 8 PIT / NODE DETAILS Version 8
Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint
HGL Flow Arriving Volume Freeboard (cu.m/s) HGL Flow Arriving Volume Freeboard (cu.m/s)
(cu.m/s) (cu.m) (m) (cu.m/s) (cu.m) (m)
Bypass 107.06 0.039 Bypass 107.07 0.071
N4 105.59 0 N4 105.65 0
N5 105.22 0.038 N5 105.22 0.071
N3 105.99 0 N3 106.08 0
LPD 105.64 0 LPD 105.69 0
SUB-CATCHMENT DETAILS SUB-CATCHMENT DETAILS
Name Max EIA Remaining EIA RIA PA Due to Storm Name Max EIA Remaining EIA RIA PA Due to Storm
Flow Q Max Q Max Q Tc Tc Tc Flow Q Max Q Max Q Tc Tc Tc
(cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min) (cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min)
Ground Bypass 0.032 0 0.032 0 5 5 50% AEP, 15 min burst, Storm 6 Ground Bypass 0.066 0 0.066 0 5 5 5% AEP, 10 min burst, Storm 6
Building 1 0.015 0.015 0 5 0 0 50% AEP, 5 min burst, Storm 1 Building 1 0.027 0.027 0 5 0 0 5% AEP, 5 min burst, Storm 1
Building 2 0.01 0.01 0 5 0 0 50% AEP, 5 min burst, Storm 1 Building 2 0.017 0.017 0 5 0 0 5% AEP, 5 min burst, Storm 1
Building 3 0.012 0.012 0 5 1 1 50% AEP, 5 min burst, Storm 1 Building 3 0.021 0.021 0 5 1 1 5% AEP, 5 min burst, Storm 1
PIPE DETAILS PIPE DETAILS
Name Max Q Max V Max U/S Max D/S Due to Storm Name Max Q Max V Max U/S Max D/S Due to Storm
(cu.m/s) (m/s) HGL (m) HGL (m) (cu.m/s) (m/s) HGL (m) HGL (m)
150mm (3) 0.002 0.68 105.587 105.23 50% AEP, 1 hour burst, Storm 1 150mm (3) 0.012 1.05 105.654 105.29 5% AEP, 2 hour burst, Storm 10
150mm (1) 0.002 0.73 105.99 105.232 50% AEP, 2 hour burst, Storm 8 150mm (1) 0.015 1.12 106.078 105.304 5% AEP, 2 hour burst, Storm 10
150mm (2) 0.002 0.8 105.636 105.23 50% AEP, 1 hour burst, Storm 4 150mm (2) 0.011 1.19 105.693 105.28 5% AEP, 30 min burst, Storm 9
CHANNEL DETAILS CHANNEL DETAILS
Name Max Q Max V Due to Storm Name Max Q Max V Due to Storm
(cu.m/s) (m/s) (cu.m/s) (m/s)
OVERFLOW ROUTE DETAILS OVERFLOW ROUTE DETAILS
Name Max Q U/S Max Q D/S Safe Q Max D Max DxV Max Width Max V Due to Storm Name Max Q U/S Max Q D/S Safe Q Max D Max DxV Max Width Max V Due to Storm
Bypass to LPD 0.031 0.03 1.434 0.028 0.03 4 1.97 50% AEP, 15 min burst, Storm 6 Bypass to LPD 0.063 0.062 1.434 0.035 0.04 4 1.32 5% AEP, 10 min burst, Storm 6
High Flow (1) High Flow (1) 0.013 0.013 5% AEP, 20 min burst, Storm 6
Low Flow (1) 0.002 0.002 50% AEP, 2 hour burst, Storm 8 Low Flow (1) 0.002 0.002 5% AEP, 20 min burst, Storm 6
Low Flow (2) 0.002 0.002 50% AEP, 1 hour burst, Storm 4 Low Flow (2) 0.002 0.002 5% AEP, 30 min burst, Storm 9
High Flow (2) High Flow (2) 0.009 0.009 5% AEP, 30 min burst, Storm 9
High Flow (3) High Flow (3) 0.009 0.009 5% AEP, 2 hour burst, Storm 10
Low Flow (3) 0.002 0.002 50% AEP, 1 hour burst, Storm 7 Low Flow (3) 0.002 0.002 5% AEP, 2 hour burst, Storm 10
Total Post-Dev Mit 0.035 0.035 1.479 0.026 0.02 4 0.79 50% AEP, 30 min burst, Storm 6 Total Post-Dev Mit 0.078 0.078 0.908 0.034 0.03 4 1.02 5% AEP, 30 min burst, Storm 2
DETENTION BASIN DETAILS DETENTION BASIN DETAILS
Name Max WL MaxVol Max Q Max Q Max Q Name Max WL MaxVol Max Q Max Q Max Q
Total Low Level High Level Total Low Level High Level
2x10kL (1) 108.74 12.9 0.002 0 0.002 2x10kL (1) 108.9 14.3 0.015 0 0.015
10kL 108.35 6.2 0.002 0 0.002 10kL 108.53 7 0.011 0 0.011
2x10kL (2) 107.92 9.2 0.002 0 0.002 2x10kL (2) 108.48 14.1 0.012 0 0.012
Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results) Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results)
{\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results).drn - DRAINS run at 16:53:13 on 14/5/2024 using Watercom Drains v2023.11.8718.30178 {\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results).drn - DRAINS run at 16:55:31 on 14/5/2024 using Watercom Drains v2023.11.8718.30178
Flows were safe in all overflow routes. Flows were safe in all overflow routes.
DRAINS results prepared from Version 2023.11.8718.30178 DRAINS results prepared from Version 2023.11.8718.30178
PIT / NODE DETAILS Version 8 PIT / NODE DETAILS Version 8
Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint
HGL Flow Arriving Volume Freeboard (cu.m/s) HGL Flow Arriving Volume Freeboard (cu.m/s)
(cu.m/s) (cu.m) (m) (cu.m/s) (cu.m) (m)
Bypass 107.06 0.055 Bypass 107.07 0.084
N4 105.6 0 N4 105.67 0
N5 105.22 0.053 N5 105.23 0.082
N3 106.04 0 N3 106.17 0
LPD 105.67 0 LPD 105.71 0
SUB-CATCHMENT DETAILS SUB-CATCHMENT DETAILS
Name Max EIA Remaining EIA RIA PA Due to Storm Name Max EIA Remaining EIA RIA PA Due to Storm
Flow Q Max Q Max Q Tc Tc Tc Flow Q Max Q Max Q Tc Tc Tc
(cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min) (cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min)
Ground Bypass 0.044 0 0.044 0 5 5 20% AEP, 15 min burst, Storm 1 Ground Bypass 0.077 0 0.077 0 5 5 2% AEP, 10 min burst, Storm 7
Building 1 0.02 0.02 0 5 0 0 20% AEP, 5 min burst, Storm 1 Building 1 0.032 0.032 0 5 0 0 2% AEP, 5 min burst, Storm 1
Building 2 0.013 0.013 0 5 0 0 20% AEP, 5 min burst, Storm 1 Building 2 0.02 0.02 0 5 0 0 2% AEP, 5 min burst, Storm 1
Building 3 0.016 0.016 0 5 1 1 20% AEP, 5 min burst, Storm 1 Building 3 0.025 0.025 0 5 1 1 2% AEP, 5 min burst, Storm 1
PIPE DETAILS PIPE DETAILS
Name Max Q Max V Max U/S Max D/S Due to Storm Name Max Q Max V Max U/S Max D/S Due to Storm
(cu.m/s) (m/s) HGL (m) HGL (m) (cu.m/s) (m/s) HGL (m) HGL (m)
150mm (3) 0.003 0.76 105.602 105.245 20% AEP, 2 hour burst, Storm 8 150mm (3) 0.014 1.06 105.668 105.303 2% AEP, 30 min burst, Storm 7
150mm (1) 0.009 1.03 106.041 105.277 20% AEP, 1.5 hour burst, Storm 1 150mm (1) 0.018 1.15 106.172 105.322 2% AEP, 30 min burst, Storm 7
150mm (2) 0.007 1.02 105.669 105.261 20% AEP, 30 min burst, Storm 5 150mm (2) 0.015 1.25 105.709 105.295 2% AEP, 15 min burst, Storm 2
CHANNEL DETAILS CHANNEL DETAILS
Name Max Q Max V Due to Storm Name Max Q Max V Due to Storm
(cu.m/s) (m/s) (cu.m/s) (m/s)
OVERFLOW ROUTE DETAILS OVERFLOW ROUTE DETAILS
Name Max Q U/S Max Q D/S Safe Q Max D Max DxV Max Width Max V Due to Storm Name Max Q U/S Max Q D/S Safe Q Max D Max DxV Max Width Max V Due to Storm
Bypass to LPD 0.044 0.044 1.434 0.031 0.04 4 1.68 20% AEP, 15 min burst, Storm 7 Bypass to LPD 0.075 0.074 1.434 0.037 0.04 4 1.28 2% AEP, 10 min burst, Storm 7
High Flow (1) 0.007 0.007 20% AEP, 1.5 hour burst, Storm 1 High Flow (1) 0.016 0.016 2% AEP, 30 min burst, Storm 7
Low Flow (1) 0.002 0.002 20% AEP, 1.5 hour burst, Storm 1 Low Flow (1) 0.002 0.002 2% AEP, 30 min burst, Storm 7
Low Flow (2) 0.002 0.002 20% AEP, 30 min burst, Storm 5 Low Flow (2) 0.002 0.002 2% AEP, 15 min burst, Storm 2
High Flow (2) 0.005 0.005 20% AEP, 30 min burst, Storm 5 High Flow (2) 0.013 0.013 2% AEP, 15 min burst, Storm 2
High Flow (3) 0.001 0.001 20% AEP, 2 hour burst, Storm 8 High Flow (3) 0.012 0.012 2% AEP, 30 min burst, Storm 7
Low Flow (3) 0.002 0.002 20% AEP, 2 hour burst, Storm 8 Low Flow (3) 0.002 0.002 2% AEP, 30 min burst, Storm 7
Total Post-Dev Mit 0.05 0.05 0.908 0.029 0.03 4 0.89 20% AEP, 30 min burst, Storm 6 Total Post-Dev Mit 0.098 0.098 1.479 0.036 0.04 4 1.17 2% AEP, 30 min burst, Storm 8
DETENTION BASIN DETAILS DETENTION BASIN DETAILS
Name Max WL MaxVol Max Q Max Q Max Q Name Max WL MaxVol Max Q Max Q Max Q
Total Low Level High Level Total Low Level High Level
2x10kL (1) 108.87 14 0.009 0 0.009 2x10kL (1) 108.93 14.5 0.018 0 0.018
10kL 108.51 6.9 0.007 0 0.007 10kL 108.55 7.1 0.015 0 0.015
2x10kL (2) 108.43 13.6 0.003 0 0.003 2x10kL (2) 108.5 14.2 0.014 0 0.014
Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results) Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results)
{\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results).drn - DRAINS run at 16:54:15 on 14/5/2024 using Watercom Drains v2023.11.8718.30178 {\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results).drn - DRAINS run at 16:56:39 on 14/5/2024 using Watercom Drains v2023.11.8718.30178
Flows were safe in all overflow routes. Flows were safe in all overflow routes.
DRAINS results prepared from Version 2023.11.8718.30178 DRAINS results prepared from Version 2023.11.8718.30178
PIT / NODE DETAILS Version 8 PIT / NODE DETAILS Version 8
Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint Name Max HGL Max Pond Max Surface Max Pond Min Overflow Constraint
HGL Flow Arriving Volume Freeboard (cu.m/s) HGL Flow Arriving Volume Freeboard (cu.m/s)
(cu.m/s) (cu.m) (m) (cu.m/s) (cu.m) (m)
Bypass 107.06 0.062 Bypass 107.07 0.093
N4 105.64 0 N4 105.68 0
N5 105.22 0.062 N5 105.23 0.092
N3 106.06 0 N3 106.35 0
LPD 105.68 0 LPD 105.72 0
SUB-CATCHMENT DETAILS SUB-CATCHMENT DETAILS
Name Max EIA Remaining EIA RIA PA Due to Storm Name Max EIA Remaining EIA RIA PA Due to Storm
Flow Q Max Q Max Q Tc Tc Tc Flow Q Max Q Max Q Tc Tc Tc
(cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min) (cu.m/s) (cu.m/s) (cu.m/s) (cu.m/s) (min) (min) (min)
Ground Bypass 0.055 0 0.055 0 5 5 10% AEP, 10 min burst, Storm 6 Ground Bypass 0.084 0 0.084 0 5 5 1% AEP, 10 min burst, Storm 7
Building 1 0.024 0.024 0 5 0 0 10% AEP, 5 min burst, Storm 1 Building 1 0.035 0.035 0 5 0 0 1% AEP, 5 min burst, Storm 1
Building 2 0.015 0.015 0 5 0 0 10% AEP, 5 min burst, Storm 1 Building 2 0.023 0.023 0 5 0 0 1% AEP, 5 min burst, Storm 1
Building 3 0.018 0.018 0 5 1 1 10% AEP, 5 min burst, Storm 1 Building 3 0.027 0.027 0 5 1 1 1% AEP, 5 min burst, Storm 1
PIPE DETAILS PIPE DETAILS
Name Max Q Max V Max U/S Max D/S Due to Storm Name Max Q Max V Max U/S Max D/S Due to Storm
(cu.m/s) (m/s) HGL (m) HGL (m) (cu.m/s) (m/s) HGL (m) HGL (m)
150mm (3) 0.009 0.97 105.637 105.276 10% AEP, 2 hour burst, Storm 3 150mm (3) 0.015 1.07 105.679 105.312 1% AEP, 30 min burst, Storm 7
150mm (1) 0.012 1.1 106.06 105.291 10% AEP, 45 min burst, Storm 5 150mm (1) 0.019 1.22 106.353 105.327 1% AEP, 25 min burst, Storm 5
150mm (2) 0.009 1.11 105.681 105.271 10% AEP, 20 min burst, Storm 5 150mm (2) 0.016 1.26 105.719 105.304 1% AEP, 15 min burst, Storm 5
CHANNEL DETAILS CHANNEL DETAILS
Name Max Q Max V Due to Storm Name Max Q Max V Due to Storm
(cu.m/s) (m/s) (cu.m/s) (m/s)
OVERFLOW ROUTE DETAILS OVERFLOW ROUTE DETAILS
Name Max Q U/S Max Q D/S Safe Q Max D Max DxV Max Width Max V Due to Storm Name Max Q U/S Max Q D/S Safe Q Max D Max DxV Max Width Max V Due to Storm
Bypass to LPD 0.053 0.052 1.434 0.033 0.03 4 1.42 10% AEP, 10 min burst, Storm 6 Bypass to LPD 0.083 0.083 1.434 0.039 0.04 4 1.28 1% AEP, 10 min burst, Storm 7
High Flow (1) 0.01 0.01 10% AEP, 45 min burst, Storm 4 High Flow (1) 0.018 0.018 1% AEP, 45 min burst, Storm 5
Low Flow (1) 0.002 0.002 10% AEP, 45 min burst, Storm 4 Low Flow (1) 0.002 0.002 1% AEP, 45 min burst, Storm 5
Low Flow (2) 0.002 0.002 10% AEP, 20 min burst, Storm 5 Low Flow (2) 0.002 0.002 1% AEP, 15 min burst, Storm 5
High Flow (2) 0.007 0.007 10% AEP, 20 min burst, Storm 5 High Flow (2) 0.014 0.014 1% AEP, 15 min burst, Storm 5
High Flow (3) 0.007 0.007 10% AEP, 2 hour burst, Storm 3 High Flow (3) 0.013 0.013 1% AEP, 30 min burst, Storm 7
Low Flow (3) 0.002 0.002 10% AEP, 2 hour burst, Storm 3 Low Flow (3) 0.002 0.002 1% AEP, 30 min burst, Storm 7
Total Post-Dev Mit 0.061 0.061 1.479 0.031 0.03 4 0.95 10% AEP, 45 min burst, Storm 7 Total Post-Dev Mit 0.109 0.109 0.908 0.038 0.05 4 1.19 1% AEP, 30 min burst, Storm 8
DETENTION BASIN DETAILS DETENTION BASIN DETAILS
Name Max WL MaxVol Max Q Max Q Max Q Name Max WL MaxVol Max Q Max Q Max Q
Total Low Level High Level Total Low Level High Level
2x10kL (1) 108.89 14.1 0.012 0 0.012 2x10kL (1) 108.97 14.9 0.02 0 0.02
10kL 108.52 7 0.009 0 0.009 10kL 108.56 7.2 0.016 0 0.016
2x10kL (2) 108.47 13.9 0.009 0 0.009 2x10kL (2) 108.51 14.3 0.015 0 0.015
Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results) Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results)
{\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results).drn - DRAINS run at 16:55:16 on 14/5/2024 using Watercom Drains v2023.11.8718.30178 {\colortbl;\red0\green0\blue0;\red192\green0\blue0;}Run Log for 24-05-13 - 23098 - Rev 2 - FINAL - Post-Mit ONLY (results).drn - DRAINS run at 16:57:02 on 14/5/2024 using Watercom Drains v2023.11.8718.30178
Flows were safe in all overflow routes. Flows were safe in all overflow routes.
Page 50
23098 - SBSMP/4
Page 32
Appendix J
STORMWATER QUALITY OPERATION AND MAINTENANCE GUIDELINES
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 51
BIO-RETENTION
OPERATIONAL MANAGEMENT AND
MAINTENANCE GUIDELINE
PROPOSED TOWNHOUSE DEVELOPMENT
5 PEARL STREET, COOROY
COOROY
23098 - O&MG
D:\JOBS\23-Jobs\23098 - 5 Pearl Street, Cooroy\Civil\Reports\SBSMP\Working\Appendices\MCE Bio Retention Operational
Management & Maintenance Guideline - 21209 - Rev 0.doc
Page 52
Page 2
Table of Contents
1 INTRODUCTION .......................................................................................... 3
2 GENERAL .................................................................................................. 3
3 RESPONSIBILITY FOR INSPECTION ..................................................................... 3
4 DATA COLLECTION / STORAGE REQUIREMENTS ..................................................... 3
5 MAINTENANCE PROCEDURE............................................................................. 3
5.1 General .............................................................................................. 3
5.2 Inspections .......................................................................................... 4
5.3 Watering ............................................................................................ 5
5.4 Vegetation Management and Weed Control .................................................... 6
5.5 Validation Water Quality Testing ................................................................ 6
5.6 Equipment Needs .................................................................................. 6
5.7 Occupational Health and Safety ................................................................. 6
5.8 Public Safety ........................................................................................ 7
5.9 Disposal Requirements ............................................................................ 7
5.10 Access Issues ........................................................................................ 7
5.11 Bio-Retention Basin Resetting .................................................................... 7
Appendix A BIO-RETENTION BASIN MAINTENANCE CHECKLIST ..................................... 8
Bio-Retention Basin Operational Management and Maintenance Guideline
Page 53
Page 3 1 INTRODUCTION The water quality treatment for the proposed development includes a proposed bio-retention basin. This document provides an overview of the maintenance requirements for the bio- retention water quality device(s) on site to ensure that they are properly maintained. 2 GENERAL Bio-retention basins are vegetated areas where runoff is filtered through a filter media layer (e.g. sandy loam) as it percolates downwards. It is then collected via perforated underground drains and flows to downstream waterways or to storages for reuse. Bio-retention basins operate by filtering stormwater runoff through densely planted surface vegetation and then percolating runoff through a prescribed filter media. During percolation, pollutants are retained through fine filtration, adsorption and some biological uptake. The vegetation in a bio- retention system is a vital functional element of the system providing a substrate for biofilm growth within the upper layer of the filter media. The proposed bio-retention basin within the site will do much of the same. It has been designed to reduce the impact of the development on the downstream waterway environment. 3 RESPONSIBILITY FOR INSPECTION The principal involved consultancy will be required to appoint an appropriately qualified consultant maintenance contractor to carry out the inspections of the bio-retention basin during the construction and on-maintenance period. At the completion of the maintenance period the responsibility to undertake the inspections and generally maintain the basin will be shifted to Body Corporate. 4 DATA COLLECTION / STORAGE REQUIREMENTS Inspection records will be required for comparison of the performance of the system. In order to assist this process it is proposed that the Bio-retention Basin Maintenance Checklist prepared by Healthy Waterways (2006) be adopted for the site. Refer Appendix A for a copy of the checklist. Copies of the completed checklist are to be forwarded to the Morgan Consulting Engineers (or other consultant nominated by the Principal) and to be provided to Council at the expiry of the maintenance period and on request thereafter. 5 MAINTENANCE PROCEDURE 5.1 General Vegetation plays a key role in maintaining the porosity of the filter media of a bio-retention basin and a strong healthy growth of vegetation is critical to its performance. Therefore the most intensive period of maintenance is during the plant establishment period (i.e. first two years) when weed removal and replanting may be required. Bio-Retention Basin Operational Management and Maintenance Guideline
Page 54
Page 4
It is also the time when high sediment loads may impact on plant growth and infiltration rates.
For this reason, the bio-retention systems are to be initially turfed. Vegetation can be
introduced when construction has been completed on an appropriate percentage of the lots
draining to each bio-retention system.
Inflow systems and overflow systems require careful monitoring, as these can be prone to scour
and litter build up. Debris can block inlets or outlets and can be unsightly, particularly in high
visibility areas. Inspection and removal of debris should be done regularly, and debris should be
removed whenever it is observed on a site.
5.2 Inspections
5.2.1 General
The bio-retention basins treat stormwater runoff through the principles of sedimentation,
filtration and percolation. These devices do not incorporate the use of screens and require
minimal maintenance during their operation. However, the systems are subject to deposition of
sediment that is filtered through the media.
Routine inspections shall be undertaken on the bio-retention basins after every significant
rainfall event (30mm of rainfall in a 24 hour period) or on a three (3) monthly basis within the
first twelve (12) months and on a six (6) monthly basis thereafter. The requirements of the
inspection for the bio-retention basin shall include the following:
1. Check for build up of sediment at pipe inlet structures;
2. Check for sediment within sub-soil drainage lines;
3. Check all concrete structures for damage and deterioration;
4. Check for the build up of vegetation matter on the bed surface and removal of
vegetation matter to ensure minimal blockage to media;
5. Check achieved flow rate through the media is maintained in accordance with the design
requirements and anticipated compaction;
6. Check inflow systems, outlets and the under drainage pipe elements to identify and
remove any blockages such as litter build up.
5.2.2 Filter Media
The filter media will be inspected for sediment deposition of the bed of the bio-retention
basins and removed as required.
Bio-Retention Basin Operational Management and Maintenance Guideline
Page 55
Page 5
Inspect for the accumulation of an impermeable layer (such as oily or clayey sediment) that
may have formed on the surface of the filter media. A symptom may be that water remains
ponded in the bio-retention basin for more than a few hours after a rain event. Repair minor
accumulations by raking away any mulch on the surface and scarifying the surface of the filter
media between plants. Any leaf litter should be removed to help maintain the surface porosity
of the filter media.
Ensure the perforated pipes are not blocked to prevent filter media and plants from becoming
waterlogged. A small steady clear flow of water may be observed discharging from the
perforated pipe at its connection into the downstream pit some hours after rainfall.
Note that smaller rainfall events after dry weather may be completely absorbed by the filter
media and not result in flow. Sub-soil drainage lines are to be flushed with clean water as
required to remove and blockage.
Sediment should be removed where it has smothered vegetation or caused blockages to the
inlets our outlet systems.
Any holes and or scouring apparent on the filter media will be repaired. Ensure no damage has
occurred to the inlet and outlet systems, if this has occurred repair as required.
5.2.3 Repair of Damage
Any accumulation of an impermeable layer, (such as oily or clayey sediment) that may have
formed on the surface of the filter media will be repaired. A symptom may be that water
remains ponded in the bio-retention basin for more than a few hours after a rain event. Repair
these minor accumulations by raking away any mulch on the surface and scarifying the surface
of the filter media between plants. Any leaf litter should be removed to help maintain the
surface porosity of the filter media.
5.3 Watering
Regular watering of the bio-retention basin vegetation is essential for successful establishment
and healthy growth. The frequency of watering to achieve successful establishment will depend
upon rainfall, maturity of planting stock and the water holding capacity of the soil.
The following watering program should be adequate following the installation of vegetation:
1. Week 1-2, 3 visits/week
2. Week 3-6, 2 visits/week
3. Week 7-12, 1 visit/week
After the first three month period, watering may still be required, particularly during the first
winter (dry period). Irrigation shall be undertaken in consultation with the Landscape Architect.
Bio-Retention Basin Operational Management and Maintenance Guideline
Page 56
Page 6 5.4 Vegetation Management and Weed Control Conventional surface mulching of the bio-retention basins with organic material like tanbark, should not be undertaken. Most organic mulch floats and runoff typically causes this material to be washed away with a risk of blocking drains. If weeds are observed within the bio-retention basin they shall be removed. Weeding will generally involve manual removal of the species. Vegetation planting densities are to be in accordance with the Landscape Architect’s design. Where necessary a biodegradable erosion mat can be applied the basin batters to help combat weed invasion and reduce the labour intensive maintenance requirements for weed removal. Herbicides are not recommended as a means of weed control. If required, however, their application is to be managed to avoid unintentional destruction of other vegetation or the introduction of chemicals that may contaminate the stormwater runoff. Where necessary, in areas that have been extensively weeded, the bio-retention basin shall be replanted with similar planting densities using suitable native species in accordance with the Landscape Architects design. Inspection of the existing vegetation is to take place and any dead or diseased vegetation shall be removed and replaced with suitable native species in accordance with the Landscape Architects design. The removal of plants, dead or diseased vegetation or weeds shall be disposed offsite at an appropriate waste management facility. All litter and debris present on the surface or batters of the bio-retention basins shall be removed and disposed offsite at an appropriate waste management facility. 5.5 Validation Water Quality Testing Validation water quality testing is not proposed for the site. 5.6 Equipment Needs The equipment required to undertake regular maintenance to the bio-retention basins will be standard hand held landscaping tools. No specific mechanical equipment is expected to be required for the maintenance of the basins unless resetting is required (refer Section 5.11). 5.7 Occupational Health and Safety The maintenance activities are to be undertaken in accordance with all current occupational and workplace health and safety legislation, regulations, codes of practice or manufacturers guidelines. Bio-Retention Basin Operational Management and Maintenance Guideline
Page 57
Page 7 For maintenance access the shallow nature of the bio-retention systems enables pedestrian ingress. As noted above no mechanical equipment is required unless resetting is required. The batter grades are considered to be acceptable and do not pose an occupational health and safety issue given proper training to maintenance personnel. The application of pesticides or herbicides in response to any weed outbreak, which cannot be controlled via manual removal, is to be undertaken by maintenance personnel in accordance with manufacturer’s guidelines in consultation with the Landscape Architect. Protective measures are to be implemented so as to minimise exposure to personnel, with personal protective measures to be the final hierarchical option. 5.8 Public Safety While maintenance is being undertaken consideration of pedestrians and cyclists is to be made due to the close proximity of the footpaths. To avoid any safety concerns it is recommended that temporary warning signs be placed at a sufficient distance to allow pedestrians and cyclists to become aware of possible maintenance vehicles/personnel when maintenance is being undertaken. 5.9 Disposal Requirements The removal of litter and debris, plants, dead or diseased vegetation or weeds are to be disposed offsite at an appropriate waste management facility. 5.10 Access Issues Suitable access to the bio-retention basins can be achieved directly from the internal road network within the site. 5.11 Bio-Retention Basin Resetting Resetting (i.e. complete reconstruction) of the bio-retention basins will be required if the system fails to drain adequately after tilling of the surface. Replacement of the filter media is required when it becomes 50% blocked, which is estimated to occur approximately every 8 to 10 years. This can be assessed via a review of sediment build up and the time necessary for the system to drain or by in-situ falling head permeability tests of the filter media. Bio-Retention Basin Operational Management and Maintenance Guideline
Page 58
Page 8
Appendix A
BIO-RETENTION BASIN MAINTENANCE CHECKLIST
Bio-Retention Basin Operational Management and Maintenance Guideline
Page 59
23098 - SBSMP/4
Page 33
Appendix K
NSC FLOOD HAZARD OVERLAY MAP
Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy
Page 60
Noosa Shire Council does not warrant the accuracy of information in this publication and any person using or relying 20/09/2023
upon such information does so on the basis that Noosa Shire Council shall bear no responsibility or liability
whatsoever for any errors, faults, defects or omissions in the information.
1:1129
Used in these records
Reference Document - Site Based Stormwater Management Plan.pdfRelated documentApplication case desk ↗
About this file
- File size
- 5.6 MB (large file)
- File type
No other editions are linked here.
Original file
Log in to download the original file
The download may take up to a minute.