Engineering Report - draft

The road reserve boundary is set back 6m from the existing nominal kerb alignment meaning
there is adequate space for a car to stop and see vehicles on Pavilion Street without being
impacted by property fences. The safe intersection distance (SISD) in each direction for vehicles
exiting the new road, when taken 3-5 back from the nominal kerb line meets the minimum
requirements in Austroads Part 4A – table 3.2 for 60kph design speed. The visibility to the north is
unobstructed and would exceed 250m. The visibility to the south is slightly impacted by the low
crest at the intersection of Sandy Street and a sag in Pavilion Street approximately 115 south of
Sandy Street in front of No 20 Pavilion Street. The visibility in this direction is approximately 120m,
however it should be noted that given this an existing street Extended Design Domain standards
could also be adopted which would reduce the visibility requirements to between 81 and 89m.
Note that some minor clearing may be necessary within the road reserve.

Preliminary design drawings have been prepared showing the new road and intersection. As there
is no truncation on the boundary of the property to the north of the new street the verge width may
not fully comply with Council’s design standards however there will be sufficient space to
accommodate the footpath and ramps to tie into the existing footpath on Pavilion Street.

    4. Stormwater Management/Bio-Retention Basin
Preliminary Drawings have been prepared for the proposed bio-retention basin. The size of the
basin is based on parameters contain in the Stormwater Management Plan prepared by Peak
Urban. Our plans demonstrate that the required bio basin filter area (120m2) and storage volume
can be provided with the allocated space in the plan of development. Please note that we have
adopted generally used 1 in 4 batters throughout except for a 1 in 2 batter on the northern side of
the basin. In addition, there is a short length of retaining wall less than 800mm in height around
the maintenance access. The extent of retaining wall is significantly less than 50% of the
perimeter of the filter area.

    5. Earthworks
The preliminary drawings show proposed earthworks for the site that includes providing level
house pads for future owners to build on. Some retaining walls will be necessary however it is
planned to minimise the extent of retaining walls for aesthetic and costs reasons.

In order to construct the bio retention basin it will be necessary to impot fill to the site to lift the
blocks and road level above the basin levels. The amount of fill will be refined during the detail
design.

    6. Water and Sewer
There is an existing sewer main traversing the site aligned with the rear of existing
dwellings/properties along Pavilion Street. The proposed lots west this alignment will be lower
than the sewer so it is proposed to service these lots using a low pressure sewer system. Lots
located east of the existing sewer will be connected using conventional gravity sewer mains.
Discussion have been held with Unitywater and they have agreed (verbally) in principle to this
arrangement as a similar system has been adopted further north on Pavilion Street. We are
awaiting confirmation of this in writing from Unitywater.

There is an existing 100mm diameter water main along the eastern side of Pavilion Street and a
road crossing to an existing fire hydrant immediately in front on the northern boundary of the site.
A new 100mm diameter main servicing the development will be provided along the new road from
this point. Refer extract from Unitywater infrastructure mapping in Appendix B



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