Reference Document - Stormwater Management Plan - RAL26/0001 (As Published)

   2.2. Proposed Development Drainage Regime
   The proposed subdivision results in the creation of one additional rear lot with an increase of
   impermeable surfaces through roof areas and driveway. It is expected that stormwater quantities will
   increase because of these impermeable areas with attenuation via above ground tanks proposed.

   To address Council’s further information request, the stormwater attenuation was amended to
   incorporate a single underground detention tank to attenuate flows from the access easement and
   future lot.

   Existing surface flows from upstream adjacent properties will remain unchanged. The existing
   drainage regime of discharging to the Lawful Point of Discharge (LPOD) at the northeastern
   boundary (unmapped channel) is maintained in the developed state. Further discussion about the
   LPOD is detailed in 2.3.

   The roof and allotment drainage system for the proposed site shall be designed to comply with:

        1. Noosa Council Planning Scheme SC6.7.6 Stormwater Management and 9.4.8 Water Quality
           and Drainage Code
        2. The Queensland Urban Drainage Manual (QUDM); and
        3. AS/NZS 3500.3:2015 - Plumbing and Drainage Part 3: Stormwater Drainage.


   2.3. LPOD Assessment
   As per QUDM’s criteria for determining the LPOD test, an assessment of the proposed drainage has
   been detailed below:

                      Criteria                                         Development Outcome
Will the proposed development alter the site’s          The proposed development must ensure that
stormwater discharge characteristics in a manner that   stormwater discharge is maintained as sheet flow to
may substantially damage a third-party property?        the discharge point and avoid concentrating flows,
                                                        increasing quantities and/or velocities.

                                                        Therefore, utilise stormwater attenuation systems
                                                        and level spreader devices to ensure the
                                                        characteristics do not damage a third-party’s
                                                        property.

Is the location of the discharge from the development   The location of the discharge is its existing location
site under the lawful control of the local government   because of the natural, steep terrain. It is part of the
or other statutory authority from whom permission       surrounding terrain and natural flow of the land and
to discharge has been received?                         eventually flows into a natural watercourse feeding
                                                        into the Lake Macdonald system.
This will include a park, watercourse, drainage or
road reserve, stormwater registered drainage            Therefore, as the immediate downstream discharge
easement, or land held by local government              point from the Site is not under the lawful control of
(including freehold land).                              the local statutory authority, further consideration of
                                                        the next criteria is required.

An authority to discharge over affected properties      In the context of obtaining authority to discharge
will be necessary. In descending order of certainty,    over the affected property, this would be a matter if
an authority may be in the form of:                     there was a material change that resulted in damage
                                                        to a third-party’s property and/or actionable
       Dedication of a drainage reserve or park        nuisance occurring.