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2 David Low Way - Attachment 3 - Civil Engineering Assessment - Sheehy 10-8-17
Attached to the e-mail Reconfiguration of a Lot (1 lot into 6) - RAL17/0501.
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Ref: bm/8531 Castaways Development Engineering Services Report
ENGINEERING SERVICES REPORT
FOR KENLYNN PTY LTD
IN SUPPORT OF THE
CASTAWAYS DEVLOPMENT, 2 DAVID LOW WAY, CASTAWAYS BEACH
Prepared by:
Sheehy & Partners Pty Ltd
3 Gregory Terrace
Spring Hill Qld 4000
Telephone: (07) 3839 3644
Email: [email protected]
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Full text of sections 2 to 13 (of 74)
Section 2
Civil Engineering Services Report 8531
Castaways, David Low Way, Castaways Beach
TABLE OF CONTENTS:
1.0 INTRODUCTION.................................................................................................................................. 3
2.0 SITE DESCRIPTION ............................................................................................................................ 4
2.1 Topography & Site Condition ................................................................................................... 4
2.2 Earthworks ................................................................................................................................ 4
2.3 Road Infrastructure .................................................................................................................... 5
2.4 Cycleways ................................................................................................................................. 6
2.5 Stormwater Drainage ................................................................................................................. 6
2.6 Sewerage ................................................................................................................................... 7
2.7 Water ......................................................................................................................................... 8
2.8 Electrical & Telecommunications Services ............................................................................... 8
3.0 Trunk Infrastructure ............................................................................................................................. 9
4.0 CONCLUSION .................................................................................................................................... 10
APPENDIX A: SUB DIVISION PROPOSAL PLAN..................................................................................... 11
APPENDIX B: GENERAL LAYOUT AND SERVICES PLAN................................................................... 12
APPENDIX C: BULK EARTHWORKS LAYOUT AND SECTIONS ........................................................ 13
APPENDIX D: CONCEPTUAL ACCESS ARRANGEMENT PLAN ......................................................... 14
APPENDIX E: UNITYWATER DETAILED INFRASTRUCTURE MAPPING ....................................... 15
APPENDIX F: SEWER RETICULATION LONGITUDINAL SECTION ................................................. 16
APPENDIX G: CODE ASSESSABLE RESPONSES .................................................................................... 17
Document Control
Version Date Author Reviewer
A 09/07/2017 Brian Mortimore -
B 20/07/2017 Brian Mortimore Scott Thomas
C 08/08/2017 - (Plan App A updated) Brian Mortimore
Document No. 8531 Castaways Development-Rev C Page 2 Issue Date: 08/08/2017
Section 3
1.0 INTRODUCTION
This Civil Engineering Services Report has been prepared to support the Castaways
Development at 2 David Low Way, Castaways Beach and to complement the application for
a Noosa Council Development Approval for Reconfiguration of a Lot 2 David Low Way,
Castaways Beach (Lot 71 on MCH 2854). This report addresses the relevant existing and
proposed infrastructure to service the development site.
The report has considered the following codes and identified the compliance measures in
Appendix G.
• Division 6 Residential Uses Code Table 14-24 For All Residential Uses
• Division 7 detached Housing Code Table 14-28 Detached houses, Ancillary dwelling units
and Secondary dwellings
• Division 12 Detached Driveways Code Table 14-48 Driveways and crossovers
• Division 13 Detached Driveways and Carparking Code Table 14-49 Driveways
• Division 14 Earthworks Code Table 14-52 Earthworks
• Division 15 Erosion and Sediment Control Code Table 14-53 Erosion and Sediment
Control
• Division 16 Existing Services Code Table 14-54 Existing Services
• Division 18 Transport, Roads and Drainage Code Table 14-59 Roads and Drainage
• Division 19 Waste Management Code Table 14-60 Waste Management
This Engineering Services Report provides information demonstrating that the site and
proposed development area can be adequately serviced.
Document No. 8531 Castaways Development-Rev C Page 3 Issue Date: 08/08/2017
Section 4
2.0 SITE DESCRIPTION 2.1 Topography & Site Condition The development site area is located on David Low Way at the northern end of Castaways Beach. The location of the site is shown outlined in red on Figure 1 below. The area for development is contained within Lot 71 on MCH 2854. The development site is located to the east of David Low Way and offers a desirable beach front location. The total area of the development site is approximately 0.9 ha. David Low Way fronts the whole of the proposed development site and provides ready access to Noosa to the north and the Sunshine Coast (Maroochydore approx. 30km) and Brisbane to the south. The Sunshine Motorway and Bruce Highway are approximately 11km and 24km away by road respectively. Figure 1 Locality Plan The proposed development area is shown in the Subdivision Proposal Plan prepared by AJS Surveys and included in Appendix A. The contours on this plan indicate that the site is divided into 3 main catchment areas by a crest located at the northern extent of the site that bisects the area under consideration. This results in two key catchments that fall to an existing gully within the site and a third that falls north from the site to an existing creek (Burgess Creek) that ultimately discharges to the east into the ocean. Typical slopes across the existing development site are in the order of 3% to 7% with a maximum of 26% at the northern boundary (refer Appendix C - Bulk Earthworks Layout and Sections). The maximum slope is located at the northern extent of the development site and forms the natural ground slope down to Burgess Creek. This slope is within the 50m riparian area that buffers the development from the creek and is outside the proposed building envelopes. The slopes within the area of the proposed building envelopes are not excessive and are consistent with acceptable slopes for this type of urban development, particularly for individually designed high specification housing that this site would attract. 2.2 Earthworks The natural slopes across the proposed site area are currently occupied by two existing properties and with limited earthworks will be generally suitable to accommodate future Document No. 8531 Castaways Development-Rev C Page 4 Issue Date: 08/08/2017
Section 5
residential development. An initial assessment of the site has been undertaken and has identified that earthworks will be required over the development site area to adjust the proposed residential allotments and provide driveway access and suitable stormwater drainage collection and outfalls (refer Appendix C – Bulk Earthworks Layout and Sections). The extent of works will be limited to minimise overall impact but to also develop appropriate lot and building envelope layouts. These layouts will not compromise specific requirements of the land owners and developers, but will be the subject of future Development and Operational Works applications and approvals from the relevant owners, developers and Council. As the natural slopes are relatively moderate, the road and allotment designs that are sensitive to the topography should result in relatively minor earthworks, within the requirements of the Earthworks Development Code. Based on the current anticipated development and industry requirements it is to be expected that most of the lots and building envelopes will result in minimal earthworks to establish allotments and building envelopes suitable for the construction of the likely properties. It is not expected that the building structures will be constructed of a slab on ground format. It is anticipated that sensitive designs should result in no retaining structures being required within the site and the site will be graded and the earthworks undertaken to achieve the requirements of the Earthworks Development Code included in Appendix G. All earthworks within the proposed development are to be undertaken in accordance with AS3798-2007 Guidelines on Earthworks for Commercial and Residential Developments. 2.3 Road Infrastructure The overall access requirements and the impacts on surrounding local road network, have been addressed in the separate Traffic Assessment Report prepared by TTM Consulting Pty Ltd. The proposed traffic augmentation works identified in the TTM Report would be delivered to provide safe and appropriate access to the site from David Low Way and within the development for property owners, visitors and service vehicles. Each individual development/applicant would need to meet requirements for parking within the properties and justify the extent of provision in the further development approvals. The proposed access arrangement from David Low Way and the internal driveway is shown on the Conceptual Access Arrangement Plan No. 17BRT0208-01 prepared by TTM Consulting Pty Ltd and included in Appendix D. The Traffic Assessment Report completed by TTM Consulting indicates that a Basic Right Turn Treatment (BAR) and a Basic Left Turn Treatment (BAL) will provide for all manoeuvres at the access with left in, left out and right in, right out movements provided from David Low Way. This can be accommodated within the road reserve with some localised widening of David Low Way into the existing western verge. The internal access will be provided from a single 7.0m wide driveway reducing in stages through 5.5m to 3m wide, depending on the number of properties accessing the driveway. The driveway will incorporate a 5.5m wide turning bay to facilitate service vehicles (12.5m Heavy Rigid Vehicle) entering, turning and leaving the property in a forward direction. Entry width will be sufficient to provide two-way accessibility from David Low Way. The 5.5m width driveway will provide for passing opportunities to the front of 3 of the 6 properties proposed within the site. The proposed access arrangement and internal driveway complies with Noosa Council Planning Scheme requirements in the Detached Driveways Code and is indicated on the General Layout and Services Plan included in Appendix B. As indicated in the Traffic Assessment Report the proposed connection to the external road has been located both horizontally and vertically to ensure appropriate sight distances are achieved. Document No. 8531 Castaways Development-Rev C Page 5 Issue Date: 08/08/2017
Section 6
2.4 Cycleways There are existing on road cycleways on David Low Way that pass the proposed development site. This cycleway provision will be maintained and incorporated in the revised access layout proposed in order to maintain safe provision for cyclists on David Low Way. It is proposed that existing 1.5m pedestrian pathway on the eastern verge of David Low Way will be maintained and realigned as necessary to suit the proposed development access layout as required by the Detached Driveways Code, with pathway ramps provided at the new crossing location. The pathway will be adjusted as necessary to comply with Noosa Council Standards for width, vertical alignment and driveway crossings to meet safety requirements. A Typical Layout proposed is shown on the Conceptual Access Arrangement Plan No. 17BRT0208-01 included in Appendix D. 2.5 Stormwater Drainage The Proposed Development Site Area contours indicate a number of stormwater catchments that discharge either to the east or to the north and the existing road reserve. It is anticipated that all catchments may require both detentioning (to alleviate any increase in flows resulting from development) and water quality treatment (to meet Noosa Councils water quality objectives). The development proposal will need to lodge a Site-Specific Stormwater Management Plan to detail the final methodology proposed to mitigate the impacts of the specific development. Indicative detentioning and water quality systems have been identified and are included in a separate report by Cardno. The report has identified a total of approximately 70m2 of detention basin (approximately 21m3) being required and accommodated proportionately within each of the building allotments to ensure that there was no increase in peak rate of runoff from the site following development. Similarly, water quality management would require an area of approximately 30m2 to be accommodated within each of the allotments. Each of the proposed allotments is of sufficient size to accommodate these requirements. It is considered that due to the nature of the underlaying sand dune a significant reduction in overland flow will occur from natural infiltration of water. The proposed mitigation measures will comply with the Earthworks Code and the Transport, Roads and Drainage Code for planning and design including stormwater capture and treatment. The separation of runoff from the external site areas and roof water that do not require water quality treatment and the internally generated water that will need to be captured and treated will be addressed to comply with the above codes as details in Appendix G. Regional flooding within the area is a result of inundation from the catchments associated with a Burgess Creek to the north of the development and from storm / high tide activity. This flooding does not impact directly on the site. No Local flooding has been identified within the site, although stormwater runoff directly from David Low Way generally falls towards the proposed development site. Mitigation works to collect and manage these overland flows may be required within the road reserve to discharge them to the Burgees Creek which forms the existing major outfall. The existing table drain within the road reserve that fronts the property will be adjusted to suit the revised access layout including the provision of a culvert crossing under the driveway as indicated on the General Layout and Services Plan included in Appendix B. Overland flow provision will be in accordance with Council’s Planning Scheme policies, as part of the proposed development. Document No. 8531 Castaways Development-Rev C Page 6 Issue Date: 08/08/2017
Section 7
Councils Planning Scheme Policies adequately deal with the requirements for stormwater drainage to be addressed with the Development Application and Operational Works Application. If natural channels are ultimately proposed to be utilised for the management of overland flow, the application for Development Approval will be required to provide flood modelling that demonstrates that the Council requirements for flood immunity to development levels have been met. Any stormwater drainage systems required to convey runoff within the Structure Plan Area is to be provided in accordance with Queensland Urban Drainage Manual and Council’s Planning Scheme Policies. 2.6 Sewerage There is no current Unitywater sewer that services the existing properties within the development site. The development site lies within the Demand Projection Catchment of the Noosa STP Sunshine Beach and within the Unitywater Future Connection Area. Unitywater provided a Services Advice Notice in February 2016 (SAN number 2016006791) and advised that no provisions have been made in their forward works programme to service the area with sewerage services. Any changes required must therefore be carried out at no cost to Unitywater. Unitywater have advised that sewerage is to be provided to the upstream property boundary to enable future main extensions. The proposed sewer connection to the development has been shown to extend to the downstream property within the road reserve and to the upstream property boundary within a compliant easement running through the allotments. Unitywater Connections Policy 2016 Sewer Connection Area maps shows no further development on the east side of David Low Way to be connected to the sewer infrastructure in the future, as this land is designated “Park, Reserves, National Parks & State Forest”. The extent of the proposed sewer is therefore compliant with Untiywater requirements. The Detailed Infrastructure Mapping provided by Unitywater (included in Appendix E) indicates the existing sewerage assets in the vicinity of the development site. A 300mm diameter sewer pressure main within David Low Way runs to the front of the development site and connects to the existing pump station located adjacent to Burgess Creek and to the north west of the site. A 525mm trunk gravity sewer runs from the north under the road viaduct to the same pump station. The development will be serviced by a new sewer connection to the gravity sewer using the existing manhole adjacent to the Creek. An initial assessment has been carried out to identify a feasible route for the sewerage reticulation system required to service the proposed development. This initial assessment is identified on the General Layout and Services Plan in Appendix B and the Sewer Reticulation Longitudinal Section included in Appendix F. It is proposed to lay a new gravity sewer connection from the existing 525mm diameter sewer manhole within the existing road reserve, following the route of the existing footpath, to a point outside the most northerly property. From a newly constructed manhole the reticulation sewer will enter the proposed development site and run along the driveway access within a 3m easement to the most southerly property boundary. Each property will be provided with a dedicated connection to the reticulation sewer to meet Unitywater requirements. It is expected that a 150mm uPVC sewer will be required to service the properties. No trunk sewer works is anticipated for the development. No other formal discussions have been held with Unitywater at this stage of development beyond the Services Advice Notice referred to above. Document No. 8531 Castaways Development-Rev C Page 7 Issue Date: 08/08/2017
Section 8
2.7 Water Unitywater provided a Services Advice Notice in February 2016 (SAN number 2016006791) and advised that the proposed development is within Unitywater’s water supply connection area and has a current service connection to the existing properties. Any changes required to this service must be carried out at no cost to Unitywater. Unitywater advised that watermains shall be provided along the full frontage of the development site to ensure that mains extensions can occur without disturbing developed footpath and the need for approval for works in roads. No future connection areas are identified on the Unitywater Connections Policy 2016 Water Connection Area maps on the east side of David Low Way south of the proposed development site to require further extension of the water main. The extent of the proposed water main is therefore compliant with Untiywater requirements. The existing water connection is serviced from a 250mm diameter trunk water main located within the gully of Burgess Creek. There is also a 250mm trunk watermain located at the frontage of the development site within David Low Way. These Unitywater services are identified on the Detailed Infrastructure Mapping included in Appendix E. It is proposed to provide a new water reticulation main from the existing 250mm AC trunk watermain in David Low Way and extend this along the full frontage of the development site within the road reserve at an offset to the boundary to comply with Unitywater requirements (1.5m). Each property will have a dedicated connection and water meter located within the property boundary for future connection to the building. Individual crossings of the proposed 10m buffer area to the front of the site designated as the Covenant Areas P, Q, R, S, T and U will be required. Connection can either be made to the building envelopes or left at the boundary with provision made under the driveway for future connection when final building development is approved. The initial assessment has identified the feasible location and routing for the watermain required to service the development site and is expected that a 100mm diameter PE reticulation main will be required to service the properties. The initial assessment has also identified there will be a need for an additional Fire Hydrant within the reticulation watermain to meet requirements for firefighting within the development. The proposed indicative watermain service is indicated on the General Layout and Services Plan in Appendix B. No further formal discussion has been held with Unitywater in addition to the Service Advice Notice received and a network analysis will be required to confirm sufficient capacity is available within the existing system. The proposed development site lies within the Unitywater Demand Projection Catchment for Sunshine Beach and has a current water connection. 2.8 Electrical & Telecommunications Services As the Electrical and Telecommunication Service providers are retail service providers, they will upon request (and payment of charges where necessary) provide pipe, pits and cable to service the proposed development site. Therefore, adequate servicing can be provided to the proposed development site. Document No. 8531 Castaways Development-Rev C Page 8 Issue Date: 08/08/2017
Section 9
3.0 TRUNK INFRASTRUCTURE There are no future trunk water supply assets identified in the Noosa Plan – Priority Infrastructure Plan within the location of the Development Site. There are no future trunk sewer assets identified in the Noosa Plan – Priority Infrastructure Plan within the location of the Development Site. There are no future stormwater trunk infrastructure assets identified in the Noosa Plan – Priority Infrastructure Plan within the location of the Development Site. There are no future planned trunk road or pathway infrastructure assets identified in the Noosa Plan – Priority Infrastructure Plan within the location of the Development Site. Document No. 8531 Castaways Development-Rev C Page 9 Issue Date: 08/08/2017
Section 10
4.0 CONCLUSION From the investigations and assessment in this Civil Engineering Servicing Report, all code requirements either are or can be met as per the Code Assessable Responses included in Appendix G. It can be concluded that the Proposed Development Site can be adequately serviced for residential subdivision. Document No. 8531 Castaways Development-Rev C Page 10 Issue Date: 08/08/2017
Section 11
Appendix A: Sub Division Proposal Plan Document No. 8531 Castaways Development-Rev C Page 11 Issue Date: 08/08/2017
Section 12
!
DRAWN
06/06/17
13/06/17
21/07/17
29/06/17
Lots
F
E
B
A
SURVEYOR
D
C
Park
Road
LJS
LGM
Identifier
Covenant
Area range
Area average
DATE
involving the land.
CHECKED LGM
712
Benefit
5/08/2017
711,713
711-715
711-714,716
711,712,714
711-713,715
REVISIONS
Amend Covenant P and Covenant areas
Add 3.0m Sewer Easement
13.
72
Widen access driveway to 6m
19.
47
Emt E & F as per updated HRV turnaround
15.
0
22
1 4 . 00
.0
0
16.
28
2
.0
19
. 00
18
. 00
17
16
Contour Interval - 1m, 5m major
18.
54
PP/41289
15.
46
TBM/STPKT
6
Nil
Nil
PP/208615
Section 13
17.
AHD
59
. 00
(RL 8.587m)
21
Statistics Table
PP/1
16.
46
16. 16.
31 16
11.
13.
52
18. 24
16
15.
89
14.
. 00
63
18.
70
. 00
22
3643 m 2
1612 m 2
11.
96
12
17.
20. 19
55
16.
DERIVED FROM PSM 18395
64 11.
66
20.
44
SIGN/
Amend Bldg Env Lot 711-713 & 716, realign Emt A-C with driveway, The text continues on section 14.