Response to Information Request Letter - 65-67 Elanda Street, Sunshine B...

           reuse proposed for the site, which demonstrates that runoff volumes to the
           downstream properties will not be increased and justifies the absence of a pipe
           connection from the site to the trunk stormwater network.
       15. Provide written approval from Unitywater for the proposed drainage and
           infiltration system.


Response
The Stormwater Management Plan has been updated in response to this Information
Request. The report now includes a direct component addressing the 20% increase in
rainfall intensity ensuring the proposed development provides suitable capacity and
consideration for increased rainfall is included within the design. The increase in rainfall is
noted as resulting in an increase in flows increase in all events the increase is a maximum
of 3L/S. The report determines that this increase in minor and with the proposed
detention tank outlet flows this increase will have no negative impacts. The proposed
treatment is therefore considered to appropriately accommodate increased rain fall.

The revised design and stormwater treatment removes the need for the infiltration
system as all roof water is able to be captured and direct to a LPD within the street. Two
7kL roof water detention tank are proposed to mitigate the flow from the roof area.
Stormwater is then discharged from the system to a LPD within Elanda Street. The system
ensures that no worsening of stormwater impacts on lots to the rear of the site.




                                               Figure 14: Drainage layout plan




Response to Information Request Letter - 65-67 Elanda Street, Sunshine Beach                 17