Appendix G Water and Sewer Analysis

                       WATER SUPPLY AND SEWER NETWORK ANALYSIS
Client: Noosa Shire Council                        Location: 62 Lake Macdonald Drive, Cooroy

2.2 Serviceability Requirements

2.2.1 Service Pressure

The services pressure requirements that were adopted in accordance with SEQ WS&S D&C Code
(2020) included:

•   Minimum 22m residual pressure during peak hour demand; and,
•   Maximum 55m service pressure.

2.2.2 Fire Flow

The fire flow requirements adopted in accordance with SEQ WS&S D&C Code (2020) are as
follows:

•   15 L/s for 2 hours with a 2/3 peak hour (PH) background demand for residential;
•   30 L/s for 4 hours with a 2/3 peak hour (PH) background demand for commercial/ industrial;
•   12m minimum pressure at flowing hydrant; and,
•   6m minimum pressure elsewhere in the system.


2.3 Scenarios

The scenarios that were used in the assessment of the water supply network were based on the
Unitywater InfoWater model supplied and are listed in Table 2. The 2036 scenarios represent the
ultimate 20-year design horizon as Unitywater did not provide a 2041 scenario. The full
development loading was added to both the 2021 and 2036 post-development scenarios.



                                 Table 2 – Water Modelling Scenarios
                           Scenario
                                                             Model Alias
                  Year     Development Stage

                  2021     Pre-development        2021_Committed_Network_2021PD

                  2021     Post-development       2021_CN_2021PD_Covey

                  2036     Pre-development        2036_Committed_Network_2036PD

                  2036     Post-development       2036_CN_2036PD_Covey


2.4 Peak Hour

The service pressure results for the critical nodes during peak hour are shown in Table 3 and in
Appendix B. The table demonstrates the lowest pressure results for the most critical node in the
development and the most critical node in the existing network during peak hour (5:30pm).
UW1686 is in the highest location in the development. NOON122 demonstrated the lowest
pressure in the existing DMA and is located along Kensington Dr.

The results demonstrated that in all pre-development scenarios there are 31 nodes that did not
meet the minimum residual pressure of 22m. These nodes are shown in Appendix B. Further, in
the post-development scenarios, no additional nodes fell below the minimum residual pressure.
Therefore, the proposed development has a non-worsening effect on the peak hour pressure. It is
recommended that Unitywater review the existing failing nodes. In all modelled scenarios within

Covey Associates Pty Ltd                      3                                   Project No: 233467
Consulting Engineers                                                              M23-0030Rpt Iss A