MCU16.0099.01, RAL19.0036 & OPW 19.0282.01 - Response to Information Request (final) 10.03.2020 · MCU16/0099.01

4.1   Trafficability
As observed during the site investigation, the trafficability of the concrete crossing, including the areas
where there is no concrete, is suitable for standard 4WD vehicles to traverse the crossing. From the
landowner’s experience, the crossing has also supported the movement of standard sized concrete
trucks. The results from the geotechnical investigation indicate that the layer of concrete is surrounded
by typically stiff clay that increases in consistency with depth, therefore larger vehicles (i.e. trucks,
cranes) should be sufficiently supported to safely traverse the crossing in order to access the site.


4.2   Manoeuvrability
Potential manoeuvrability issues of semi-trucks of lengths between 13m and 18m in length with 5-6m
clearance in width between adjacent trees within the crossing, limiting turning on the crossing. Vertical
clearance of trees appears to be satisfactory however caution with a few small overarching branches
is recommended.


4.3   Access
There concrete crossing is located at the bottom of the gully in a natural watercourse and below a dam
wall’s overflow outlet. As the structure is an obstruction within a natural watercourse and there are no
underground pipes to allow the water to travel under the crossing, it is expected that access to the site
will be restricted during the wetter parts of the year. Future plans for construction or access for
maintenance should take this into account.

5     Conclusions and Recommendations
The existing waterway has been filled with rock and concrete, and the concrete crossing is currently in
good condition with no major cracking and very minimal crumbling. The sight of the crossing has been
observed as clean and neat. From the results of the geotechnical investigation, the soil surrounding
the crossing structure is typically stiff clay that increases in consistency with depth. The history of the
crossing and findings from the site investigation conclude that the existing crossing in its current
condition is trafficable and suitable for 4WD vehicles and larger vehicles (i.e. trucks, cranes) to
traverse in order to access the site.
As discussed in Section 4.3, the crossing structure blocks a natural waterway channel and there are
no means for the water to flow through under the crossing. Therefore, it is recommended for vehicles
to avoid traversing the crossing when the water is high, particularly during wet periods of the year.




Should you require additional information or clarifications please don't hesitate to contact me


Kind Regards



Con Sweeney
Senior Civil Engineer, Civil Infrastructure
RPEQ 14331




                                              Project 239146 File 247473 Cooroibah Waterway Crossing_Rev0.docx 2020-02-192020-02-19 Revision A Page 8