17 Bottlebrush Avenue, · MCU26/0001

The time of concentration (Tc) of 7 minutes was determined using figure 4.4 – Overland sheet flow times (refer to
Figure 2-3) in accordance with Table 4.6.6 of QUDM. This approach provides a reliable estimate of the travel time
for runoff from the hydraulically most distant point in the catchment to the outlet.

A maximum flow path length of 34.0 m was adopted, based on survey data collected by Eagle Survey Pty Ltd in
2025 (refer to Figure 2-2).

To refine the analysis, the following factors were incorporated to ensure accuracy and representativeness of the
stormwater design:

     •    Surface roughness and vegetation cover, which influence flow resistance and travel time

     •    Topographic gradients, confirming alignment between flow velocities and assumed conditions

     •    Site hydraulic connectivity, including potential depressions or ponding areas, verifying the
          appropriateness of the adopted Tc.




Figure 2-2 Max overland flow path




Figure 2-3: Overland sheet flow times (QUDM, 2025)




 17 BOTTLEBRUSH AVENUE, NOOSA HEADS
                                                7 January 2026                                      P a g e |7
 Stormwater Management Plan
 Client Reference: P0433-25-001
 Prepared for Made Capital PTY LTD