Appendix E - Stormwater Management Plan

The following documents have also been provided to Council together with this submission and must be read in
conjunction with this report:

•   Response to Stage 2 Operational Works Approval Conditions Letter (No. 16-001014.02L.ms.cm.docx dated
    January 2017) – provides a summary of responses to Council’s Stage 2 Operational Works Approval Conditions
    regarding stormwater management.
•   Stormwater Management Plan (SWMP) Report (No. 16-001014-01B dated January 2017) – provides updated details
    of the stormwater management strategy, with corresponding analysis and investigations.

The design, management and maintenance procedures for stormwater management devices detailed in these
documents, also address previous concerns from Council and are in accordance with past approvals.

This report provides details on peak flow, stormwater quality and water stability management to demonstrate compliance
with the relevant local and state guidelines and Council’s requirements. The site development layout is generally in
accordance with the approved layout and the stormwater management strategies remains consistent with previously
approved documentation.

1.1       SCOPE OF THIS REPORT
The scope of this report includes the following:

•   Peak flow (or hydrological) analysis using XP-RAFTS software to determine existing peak flows and developed
    mitigated peak flows from the site, to ensure no adverse impact as a result of the development;
•   Stormwater quality analysis using MUSIC software to determine the adequacy of the proposed SQIDs to meet the
    Water Quality Objectives (WQO’s) required under the State Planning Policy (SPP, 2014); and
•   Management of Waterway Stability required under SPP (2014).

While a flood investigation has not been undertaken in this report, it is noted that flood information was previously
provided to Council in Letter No. B14158.W.10LA.AMcP.ms.docx dated 21 April 2016. This document demonstrated no
loss of regional floodplain storage and therefore no increase in the severity of flooding or interference with the existing
watercourse. The peak flow investigation and internal drainage strategy detailed in Section 3.2 demonstrates no
worsening in peak flows discharging from the site, also demonstrating that the development will not adversely impact
flood conditions downstream. Since the site strategy is generally in accordance with concept designs previously provided
to Council (i.e. earthworks, drainage and stormwater management solutions) the above outcomes are maintained.

1.2       PREVIOUS DOCUMENTATION
The following documentation has been previously prepared by Calibre Consulting (Qld) for the Cooroy Retirement
Community development:

Reduced Site Layout - MCU Development Application
• Concept Stormwater Management Report (No. B07056.W-02A dated June 2008) – in support of the DA;
• Concept Stormwater Quality Management Plan (SWQMP) Report (No. B14158.W-01A dated December 2014) in
   support of the permissible change application;

Reduced Site Layout – Bulk Earthworks Approval
• Stormwater Management Construction and Maintenance Plan (SMCMP) Report (No. B14158.W-04A dated
   September 2015) – in support of the Operational Works - Bulk Earthworks Application; and
• Framework Letter Report (No. B14158.W.07L dated 8 October 2015) – Addressing Council’s Change to Existing
   Approval Condition Item 72 (dated 2 March 2015).

Reduced Site Layout - Stage 1A Operational Works Application
• Stormwater Management Plan (SWMP) Report (No. B14158.W-05B dated 2015);


16-001014-01B | STORMWATER MANAGEMENT PLAN                       COOROY RETIREMENT COMMUNITY, TRADING POST
(SWMP) | PALM LAKE RESORTS                                                                   ROAD, COOROY                 |2