2018-01-15 General Committee Agenda

GENERAL COMMITTEE MEETING AGENDA                                                15 JANUARY 2018


Condition 47
47.   All stormwater drainage shall be managed so that:
      a.   there is no net increase in 1 year ARI peak stormwater flows from the site at any
           stage of the development; and
      b.   the discharge of stormwater from construction or completed stages of the site does
           not affect the approved design residence time of the Noosa Springs Golf Course lake
           system.
Applicant’s requested change
This condition currently requires no net increase in 1 year ARI peak stormwater flows from the
site at any stage of the development. As discussed through the detailed design process, and
associated operational works package associated with the development, there is a minor net
increase in the 1 year ARI event from the site of 0.08m3/s. This increase is considered minor
when compared to the total site 1 year ARI event flow of 1.709m3/2.
Although there is a minor increase in flow, it should be noted that the site is 51% impervious
which is generally in keeping with the 50% imperviousness assumed in the master drainage plan
report for the site. The pipe drainage infrastructure in Resort Drive and the stormwater property
connections to the site have been designed for the minor (10 year ARI) storm events so that the
minor net increase in the 1 year ARI can be accommodate without negatively impacting the
existing drainage infrastructure. Furthermore, the minor increase in the 1 year ARI Flow from the
site will be mitigated by the storage provided within the extensive pipe network, bio-retention
basins and swales within the site.
In light of the above, it is requested that Condition 47 be amended to read:-
47.   All stormwater drainage shall be managed so that:
      a.   there is no net increase in 1 year ARI peak stormwater flows from the site at any
           stage of the development; and
      b.   the discharge of stormwater from construction or completed stages of the site does
           not affect the approved design residence time of the Noosa Springs Golf Course lake
           system.
Assessment
The request to amend this condition was referred to Council’s Environment Officer who advised:
Condition 47(a) is applied to ensure the development meets the State Planning Policy, therefore
we cannot remove its intention completely.
The condition can be reworded to achieve the same outcome of the State Planning Policy being
that the applicant will need to demonstrate the Peak 1 year flows will not cause scour to any
receiving water ways.
Condition 47(a) can be reworded as follows:
a) there is no net increase in 1 year ARI peak stormwater flows from the site at any stage of the
development that will cause scour at any point in the receiving environment. Where there is an
increase in 1 year ARI peak stormwater flows, a Hydraulic Engineer must certify that the increase
will not be responsible for any scour in the receiving environment
It is recommended that condition 47(a) be reworded in accordance with the advice of Council’s
Environment Officer.




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