Hydraulic Assessment 29 August 2024

FIGURE 3.2: TUFLOW SETUP


  3.2.1       Results
The hydraulic result maps are presented in Appendix C and have been prepared to detail the peak flow depth, velocity and height in relation
to the dam spillway and outlet channel. The result highlight that flows over the dam spillway do not overtop the dam embankment crest or
associated discharge channels.

Peak flow depths of up to 0.90 m and 0.65 m are noted through the dam spillway and outlet channel respectively in the 1% AEP event.
Velocities in the spillway channel are generally around 3.5 m/s, with a peak velocity of 5.1 m/s at the outlet of the channel.

The peak 1% AEP flood level in the dam is 112.05 m AHD, which demonstrates flood flows up to the 1% AEP event will not exceed the
current minimum crest height of 112.24 m AHD.

3.2.1.1 Spillway
The minimum overtopping level for the dam crest has been obtained from the survey at 112.24 m AHD. To maintain the necessary freeboard
to prevent water overtopping the embankment including during flood events, the minimum level of the spillway must be set at least 1 meter
below the crest level. The existing spillway level downstream of the blockage caused by the tree roots is noted at 111.09 m AHD, ensuring a
freeboard of 1.13 meters under normal conditions.



38 BARINA COURT, POMONA I BBNE00000_0020-REP-001-0                                                                                       9