Information Request OPW21 0250

Officer: 	Diogo Carrico
Direct Telephone: 	07 53296465
Our Reference:	OPW21/0250
Your Reference:	160-001
20 October 2021
Bax Engineering Pty Ltd
2261 David Low Way
PEREGIAN BEACH   QLD  4573
[email protected]
Dear Sir
Information Request
Planning Act 2016
I refer to your application and advise that Council requires further information to satisfactorily assess the proposal.
application details
Application No.	OPW21/0250
Street Address:	2 Pearsons Rd Cooroy Qld 4563
Real Property Description:	Lot 3 RP 113733
Planning Scheme:	Noosa Plan 2020 (25 September 2020)
INFORMATION REQUIRED
The information requested is set out below:
Issue – Proposed Lot 16’s Access
The crossover for proposed lot 16 is constructed (Pearsons Rd) but the access is not sealed in accordance with council’s standard drawings RS-049 and RS-050.
Information Required
Provide amended plans demonstrating compliance with council’s standard drawings RS-049 and RS-050 for proposed lot 16.

Issue – Bin Pads
Condition 9 of the higher order approval RAL20/0021 requires that concrete bin pads for Lots7-11 must be constructed on the kerb side of the new road. The provided documentation does not include these elements.
Information Required
Provide amended plans demonstrating compliance with the requirements of condition 9 of the higher order approval RAL20/0021.

Issue – Street Lighting
Condition 8 e. of the higher order approval RAL20/0021 requires installation of street lighting on the road reserve and where required on the pathway between proposed lots 6 & 7and Spotted Gum Court to ensure this pathway is appropriately lit.
A review of the most recent submitted drawings includes lighting on the proposed pathway between lots 6 & 7.
Information Required
Provide certification, from a qualified person, certifying that the proposed lighting arrangement/type complies with relevant public lighting standards and will not cause a nuisance (e.g. light spilling) to proposed lots 6 & 7 as well as existing lots 39 and 40 on SP305293.

Issue – Lot 2 Driveway
Conditions 10 & 11 of the higher order approval RAL20/0021 require that a residential driveway must be constructed for Lots 2-15 (please note typo on condition 10 which indicates lots 3-15).
Information Required
Provide amended plans which include a residential driveway being constructed for proposed lot 2.

Issue – Pram Ramp
Condition 12 e. of the higher order approval RAL20/0021 requires that pram crossings on either side of Spotted Gum Court are constructed – to provide connectivity from new pathway between proposed lots 6 & 7 and existing pathway on the south side of Spotted Gum Court.
The submitted documents do not include a pram crossing to the south side of Spotted Gum Court.
Information Required
Provide amended plans demonstrating compliance with the requirements of condition 12 e. of the higher order approval RAL20/0021.

Issue – Stormwater Quality
The overall approach to stormwater quality treatment in the updated SWMP is supported, however some details need to be addressed to confirm device size.
Information Required
Provide an updated SWMP and MUSIC model which addresses the following issues:
Lot 15 appears to bypass the bioretention basin and this should be reflected in the model;
Estimates of roof area should be based on typical dwelling size of 250m2;
The rainfall station should be updated to be the closest representative site, which is Cooroy Composite (40059);
The 2 external residential properties which drain to the bioretention basin should be included in the MUSIC model. Pollutant load reduction targets do not need to be achieved for the external properties and the modelled load reductions should be factored accordingly when the results are presented.

Issue – Bioretention Drawings
The details on Drawing 406 seem to reflect an earlier version of the bioretention concept and SWMP. Insufficient detail is also provided to properly assess the design.
Information Required
Provide updated drawings for the bioretention basin which comply with Section 3.8.2 (Detailed Design Drawings) of the Bioretention Technical Design Guidelines (Water by Design, 2014), and which specifically provide the following:
Maintenance access and forebay as per IPWEAQ standard drawings;
Detailed plan view including layout of subsoil drains and all sub-soil drain sizing;
Overflow weir details;
Sub-soil drain cleanout details;
Filter media profile consistent with SWMP;
Long-section through basin showing inlet, surface and outlet levels.

Issue – Detention Modelling
The details on Drawing 406 seem to reflect an earlier version of the bioretention concept and SWMP. Insufficient detail is also provided to properly assess the design.
Information Required
Provide an updated SWMP and associated modelling which addresses the following issues:
The adopted pervious initial loss is significantly lower than recommended by QUDM or obtained by ARR DataHub for this location. The pre-development peak flow estimates are also significantly higher than those provided in the previous Callaghan and Toth report (~30% higher for the 1%AEP event). This could mean that detention storage volume is consequently under-sized. Either justify the current approach or adopt at least the minimum recommended value of QUDM;
Explained how the bypass flows via the 525mm dia RCP have been accounted for in the model for the external catchment;
Climate change is required to be accounted for. An additional model scenario for the 1%AEP (2100) event should be provided;
Clarify how the detention stage-volume relationship has been estimated and confirm extended detention of the bioretention basin is excluded;
It seems that the pedestrian pathway acts as a spillway. This is potentially a hazardous arrangement. Confirm the event AEP that first activates the spillway and confirm hazard (D, V, DxV) during the peak 1%AEP (2100) event and that conditions are safe for pedestrians during such an event;
Condition 16 of the RAL approval requires that a range of durations are analysed and no-increase in peak flows is demonstrated for a range of AEP-duration combinations relevant to the downstream land/waterway. This has not been shown;
Confirm that ensemble temporal patterns have been used for the analysis or justify why another method was adopted.

Issue – Drainage Design
The details on Drawing 406 seem to reflect an earlier version of the bioretention concept and SWMP. Insufficient detail is also provided to properly assess the design.
Information Required
Provide updated drainage design drawings and supporting calculations which address the following:
How has the external catchment overland flow from Spotted Gum Court been accounted for in the major event hydraulic calculations? Sheet 405 appears to show identical catchment areas for both minor and major events for all structures;
Provide detailed contours for the detention basin and show that the basin surface grades to an outlet to the swale to avoid being waterlogged;
It seems that the bioretention and detention basin will inundate Lot 15 and adjacent existing lot 9 RP881300 which have minimum levels of around RL 101.5. Sheet 401 shows the bioretention basin surface at RL 102.0, which is higher than parts of Lot 15 and also slightly higher than outlet 8/1.  Similarly, the detention basin RL is shown as RL 100.55, which would put the maximum water level above some parts of Lot 15 and adjacent existing lot 9 RP881300 also. Show that ALL los (existing and proposed) achieve the freeboard specified by QUDM above the basin peak 1%AEP (2100) water level;
The detention basin outlet details on Sheet 401 do not appear to match the outlet details documented in the SWMP. Provide a detailed plan view of the detention basin and sections of the outlet structures and embankment, so all details are clearly identified. Where the outlet involves an extended length of pipework, provide HGL analysis for the 1%AEP (CC) event for that section and demonstrate that the outlet properties assumed in the model will be achieved (i.e. that the flowrate from the basin won’t be outlet controlled by the losses through the pipe rather than through the orifice or overflow weirs).

Issue – Stormwater Connection (Lot 1 on RP113733)
The submitted plans for the assessment of the higher order application (RAL20/0021) indicate a stormwater grated pit on the SE corner of Lot 1 on RP113733 – to provide a stormwater connection point from this property to the subject application’s stormwater system.
Information Required
Provide amended plans showing stormwater grated pit ref. 1/3 on the SE corner of Lot 1 on RP113733 – this connection must be covered under an easement over proposed Lot 10 to the benefit of existing Lot 1 on RP113733.

Issue – Landscaping
The following amendments to the proposed landscaping plans are required.
Information Required
Provide an amended Landscape Plan detailing the removal of the street trees in the narrow planting area between the concrete pedestrian footpath and the back of the kerb on the southern side of Blue Wren Place.
Provide an amended Landscape Plan detailing the incorporation of 4 additional street trees where reasonably possible on the northern road reserve of Blue Wren Place.
Provide an amended planting schedule on Sheet LD3 detailing the incorporation of a mix of the following street tree species in 45 litre:
Buckinghamia celsissima;
Elaeocarpus obovatus;
Syzygium oleosum;
Waterhousia floribunda.

due date for response to information request
The due date for providing the requested information is 24 January 2022. Email your response to [email protected]. Please advise Council of your response to this information request in accordance with section 13 of the Development Assessment Rules.
If you do not provide a response before the due date, it will be taken as if you have decided not to respond to the information request and Council will continue with the assessment of your application.
other details
You can follow the progress of this application online at www.noosa.qld.gov.au. The “Online Services” page can be accessed via "Quick Links" on the left hand side of the screen.
Should you have any further queries in relation to the above, please do not hesitate to contact me on the number above.
Yours faithfully

Diogo Carrico
Development Engineer

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PO Box 141		P. (07) 5329 6500	[email protected]	
	TEWANTIN  QLD  4565	F. (07) 5329 6501	www.noosa.qld.gov.au
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