08/1128 - Response to Information Request [As Published] · 132008.1128

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11/08/2008 17:01 61-74471962 NOOSA SHIRE COUNCIL PAGE 65/89

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42. The discharge velocity for Q2 events in the developed scenario exceeds the undeveloped
case. Council also notes that the Lot 6 bioretention basin reduces the Q100 flows to velocities
experienced in Q10 events and Q10 flows to velocities experienced in Q2 evants, Due to the
sensitivity of the area and number of significant species residing within the receiving
environment, Council requests comment regarding the impact of such event flow reductions
on the ecology on significant species.

Provide ecologist comment of the impact of on site detention of water (i.e. volumes within
rainwater tanks) to downstream uses.

Council requests an ecologist comment regarding the impact of the concentration of flows’: ”
from the site to the designated discharge areas.

Drawing 0673_DA11 Dated May 2008 by Smith+Tracey Architects shows that a gazebo; and:
terrace is:intended to be located within the proposed bioretention basin at Lot 6 on RP901364-©
With respect to the integral function of planting densities within bioretention basins,
demonstrate and provide RPEQ certification that the proposed terrace and gazebo will not
ah bap eee S adversely ‘affect the MUSIC modelling results and intended water quality Improvement function
Heat - of the bioretention basin.

48. The detention basin on Lot 1 SP177650 is located directly adjacent to the 20-metre buffer. It
Is considered desirable to have the detention basin setback from the buffer to allow for its
construction without disturbance to vegetation within the buffer.

External Traffic Generation

47. It 1s noted within the Traffic Assessment Report by ARUP that a SIDRA analysis has been
undertaken, however no output data or digital filas have been provided for Council to assess.
Accordingly, please provide a digital copy of the calibrated SIDRA analysis with the digital data
files and traffic report certified by a RPEQ specialising in traffic engineering, as Council will
independently review the data.

Please note that the Noosa region has been developed with a primary focus on maintaining a
low stress relaxed environment and the road network has been specifically designed to avold :
conditlons typically found in cities, such as congestion / delays, four lane roads, and traffic
lights. There are currently only 3 traffic lights within the Noosa region, two of which are for
pedestrian. movements.

To maintain this standard Noosa has designed the road system with a much lower degree of
saturation, with roundabouts being designed with a maximum Degree of Saturation of 0.7,
which has also been confirmed through calibration of the operating conditions of a number of
existing intersections within the Noosa region.

i Furthermore, ithe Noosa region has a high percentage of older / slower drivers and
i intersections do not handle the same capacity that Is often experienced in city areas.

Accordingly, the SIDRA analysis undertaken should be based on a maximum degree of
saturation of 0.7 and the results and digital data of the intersection analysis submitted for
Council to review and carry out our own SIDRA analysis.

In this regard there are 3 distinct scenarios that need to be analysed:

a) The existing situation needs to be modelled and calibrated to reflect the manual turning
movement counts undertaken on Wednesday 28 May 2008.

b) The existing situation, as modelled in (a) above, needs to be projected to the design
horizon year and re-analysed, And

c) The existing situation, as modelled in (b) above, needs to have the development traffic
added as projected to the design horizon year and re-analysed,

Should any improvements to the various intersections being analysed need to be undertaken
as a result of the proposed development, please provide a recommendation as to what
should be done. ,