Narellan Creek Overland Flood Study (Vol 1) - Flipbook - Page 70
Narellan Creek Catchment
Flood Study
The updated impervious were used to re-calculate weighted average impervious areas to
reflect future development across the Turner Road Growth Area and update the WBNM
hydrologic model. The updated hydrologic model was used to re-simulate the design 20%
AEP, 5% AEP, 1% AEP and 0.2% AEP design storms.
The updated design hydrology was then applied to an updated TUFLOW hydraulic model. In
addition to the updated hydrology, the TUFLOW model was updated to reflect the
realignment of the creek draining through the area and the filling of habitable areas to the
flood planning level (i.e., 1% AEP flood level +0.5 metres). The updated Hydraulic model
was then used to re-simulate the design 20% AEP, 5% AEP, 1% AEP and 0.2% AEP design
floods.
Flood level difference mapping was then prepared to quantify the impact that future
catchment development is predicted to have on
