1909-13367 SRA referral response approved docs

developed and existing cases for each scenario were subtracted. For the events with blockage the
developed case with blockages peak water elevation grid was subtracted from its respective existing
case peak water elevation grid file.

For clarity only positive afflux results greater than 0.01m shall be displayed as negative afflux is not a
worsening.
Full detailed afflux maps and velocity afflux maps are presented in Appendix BC.
Velocity afflux is not present within neighbouring properties including road reserves for any of the
design events. The exception to this are small afflux (<0.25m/s) areas generally located west of
Ferrell’s Road and are not considered to be caused by the proposed development. Afflux within the
development site is present in small amounts (<0.50m/s) in some events, however as it is contained
within the development site it is not considered to be causing a nuisance to neighbouring properties or
developments. Velocity afflux maps for all design events are presented in Appendix BC.

4.3.1 50 % Ae p Af f l ux ( no b loc k ag e)

No afflux is recorded within neighbouring properties for this design event. Afflux is concentrated at the
location of a 1D/2D connection point from the developed portion of catchment 5.01. This afflux is due
to the concentration of flows and is localised within the gold course. No afflux is reported within the road
reserve or rail corridor. Please refer to Appendix BC for all flood and afflux maps.


4.3.2 50 % Ae p Af f l ux ( w it h blo ck ag e)

As per the above case no neighbouring properties experience afflux due to the proposed development.


4.3.3 20 % Ae p Af f l ux ( no b loc k ag e)

No afflux is reported in the vicinity of the proposed bridge or on neighbouring properties. A small amount
of afflux is recorded (0.01m) at the western side of the model (west of the Cooroy dolphins swimming
club) which is located at the 2D connection point. No changes are proposed in this location and so it is
not possible that this afflux is the result of the proposed development. As per the above case some
localised afflux is present at the discharge point of the developed portion of catchment 5.01.


4.3.4 20 % Ae p Af f l ux ( w it h blo ck ag e)

Afflux is as per the above case.
4.3.5 10 % Ae p Af f l ux ( no b loc k ag e)

The only afflux that is present in this model is located west of Ferrells road as per above models. The
maximum afflux in this location is 0.019m.

No afflux to neighbouring is reported in the vicinity of development except for the above mentioned
afflux north east of the development at the outlet of basin 2.
4.3.6 10 % Ae p Af f l ux ( w it h blo ck ag e)

Afflux is as per the above case.
4.3.7 5 % Ae p Af f lu x ( n o b l oc ka ge)

No afflux is reported within neighbouring properties except for small amounts located west of Myall
Street north of the development (maximum of 0.026m). Some afflux is reported in the vicinity of the
basin 2 which as described above is due to the concentration of flows to a single point. Additionally this
afflux is localised and does not affect the rail corridor or road reserve.



                                                Flood Study                                              31
S19-007                                  122 & 144 Myall St, Cooroy