04/12/2024 | Press release | Distributed by Public on 04/11/2024 22:25
Published on 12 April 2024
$7.5 million from the Capital Works Program 2023-24 has been allocated to repair the significant road damage caused by the October 2022 rain event across the multiplicity. Read more about it in Councils Annual Plan and Budget Estimates 2023-24
Oonah Road East (Guide Road)
The residual landslip material has nearly all been removed. This has been located to a depth of 13m below road level and has required a considerable volume of unsuitable material to be removed in a staged method to ensure no catastrophic embankment failures
Rock fill is starting to be placed to rebuild the embankment
Above: Unsuitable material at a depth of 13m has been removed
Above:Rock fill is being used to rebuild the embankment
9 February 2024
Oonah Road (Douglas Road)
Above: Backfilling of the rock buttress is nearly complete
Oonah Road East (Guide Road)
Oonah Road Far East
Above: Rock filling has commenced in the hairpin at Oonah Road Far East.
Thank you so much to the community for your patience as we rebuilt this road.
Oonah Road (Douglas Road)
Oonah East (Guide Road)
Above: Oonah Road East (Guide Road) - Sheet pile wall will be constructed through the landslip area
Oonah East
Above: Rock fill in the hair pin has commenced
Oonah Road (Douglas Road)
Harding Hotmix has commenced setting up site for road remediations on Oonah Road - West of Douglas Road. The road will be restricted to one lane, still allowing for vehicle and truck access to continue. As the width of the road will be limited, heavy vehicles are not permitted through the site. For heavy vehicles, please use the detour via Lockwood Creek Road. To ensure the safety of road users and workers, please obey all signage and speed limits.
Oonah Road Far East
New road fill sitting on top of the old road
Dig out on slip end has exposed a secondary old pipe
Oonah Road East
The Sheet pile design is being finalised which will be required prior to the major excavations works.
Oonah Road (Douglas Road)
Contractor Harding Hotmix will commence on site the third week of December. They will begin replacing the culvert and rebuilding the embankment.
Thank you so much to the community for your patience as we rebuilt this road.
Oonah Road West - Completed
Asphalt has been laid with culverts and rock fill drains free flowing with water.
Civilscape have done an excellent job given the amount of unknowns at the start and working through some very wet weather over winter.
Design works have now been completed with major excavation works required to remove the landslip material (see diagram section A-A). Once the material has been removed, the road will be reinstated to the same alignment.
Corner works will be completed at the same time which includes the fill batter repair, culvert extension and road drainage improvement.
Civilscapes will commence works in early November.
Thank you so much to the community for your patience as we rebuilt this road.
Oonah Road West - OPEN
Civilscape have done remarkably well to have removed so much unsuitable material and place an extraordinary amount of rock in just 5 weeks, especially given the weather conditions.
Oonah Road West will be re opened to the public from 5pm this afternoon (Friday 21 July). Gravel Road and Road Work signage is still in place with maintenance work to continuing next week.
Oonah Road West will re-open at 5pm on Friday 21 July 2023
1600 tones of rock was brought to the site
Thank you so much to the community for your patience as we rebuilt this road.
Oonah Road West - Closed
Some small set backs. Oonah Road West will be closed for another week due to delays in laying the final road base.
Civilscape are currently digging out the last ramp drain, and will be laying the final road base gravel over the current loose rock within the next few days.
Oonah Road East - Road Remains Closed
Geotechnical investigations are showing that Oonah Road East is still an active landslip. Underground wells and movements are continuingly being monitored. For the publics safety, Oonah Road East will remain closed to all traffic until further notice. Final remediation designs for restoration are ongoing.
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
Oonah Road West - Closed
We're almost there!
Civilscape imported around 1000T of rock yesterday and will have around 600T more by the end of today (Friday 7 July).
Water is freely draining at the bottom of the rock fill per the drainage channels. All going well next week (weather permitting) road gravel will go on and prepped to hopefully open the road next weekend.
Oonah Road East - Road Remains Closed
Geotechnical investigations are ongoing.
Oonah Road West - Closed
During reconstruction works, unsuitable material has been located at the subgrade level.
The road will be closed between Martin Place and Douglas Road for up to four weeks whilst the unsuitable material is removed and the road reconstructed. Council apologise for the delays.
Unsuitable material located at the subgrade level
Oonah Road East - Road Remains Closed
Geotechnical investigations are ongoing.
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
Oonah Road West - Road Open to Single Lane Only
Civil scape contracting are currently placing and compacting sub-base material in preparation for top base material.
About 70% of the remediation works have been completed on Oonah Road.
compacting sub-base material
compacting sub-base material
Oonah Road East - Road Remains Closed
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
Oonah Road West - Road Open to Single Lane Only
Consolidation work is near complete on the East Bound lane with drainage work commencing on the west bound lane.
Fun fact to date nearly 2,000tons of ballast material (blue metal) has been imported to site, considering this comes in at the rate of 36tons per truck load - that's a lot of truck loads!
Consolidation work may be finished within two weeks (weather dependant) then work can start rebuilding the road to final level.
Laying the ballast material
commencing drainage works on the west bound lane
Oonah Road East - Road Remains Closed
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
Oonah Road West - Road Open to Single Lane Only
Repair work to Oonah Road West was affected by 45mm of rain through the week.
Excavations are continuing in order to establish a firm base for rebuilding the road. Site workers have exposed a number of subterranean drains - as remediation work continues.
subterranean drains exposed
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
Oonah Road West - Road Open to Single Lane Only
Contactors have removed and stockpiled the existing gravel layer and will mix it with road gravel to reinforce it's strength.
The lower culvert embankment excavation works have commenced, with water beening discovered entering from the uphill side and getting under the culvert. It appears to be old water trapped in the embankment.
Test holes either side of culvert will be cut to determine the extent of embankment water. This section will be monitored to see if any more water appears.
existing top gravel layer is removed
new drainage being installed
Oonah Road East - Road Remains Closed
Oonah Road East will remain closed to all traffic until further notice as a final design for restoration is still to be confirmed.
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
Oonah Road West - Road Open to Single Lane Only
Contractors have commenced remediation work on Oonah Road West.
Works to rebuild the road include
(above) Remediation work begins at Oonah Road West clearing overhanging trees
Oonah Road East - Road Remains Closed
We are still some way off identifying the most suitable solution for this part of Oonah Road, and subsequently Oonah Road will be closed in to the near foreseeable future.
Oonah Road West - Road Open to Single Lane Only
Repair work to Oonah Road West will commence in the next few weeks and will include:
Oonah Road East - Road Closed
Oonah Road East has sustained significant land movement and is still an active slip.
Investigation work in this area is still continuing to identify the best sustainable solution.
Potential options being considered:
Land acquisitions may be required, depending on the solution.
We are still some way off identifying the most suitable solution for this part of Oonah Road, and subsequently Oonah Road will be closed in to the near foreseeable future.
Thank you to the community for your understanding as we continue to work hard for you on repairing these roads
November 2022
A geotechnical investigation was conducted on the eastern landslide on the 27th of October and the western landslide on the 2nd of November 2022. A public meeting will be scheduled next week for Council Representatives to answer questions regarding the status of the findings to date. Further information will be provide regarding the date and time of the public meeting
Two landslides have occurred along Oonah Road; one within the western portion of Oonah Road (located approximately 500m east of the East Cam River) and the other towards the eastern end of Oonah Road (located approximately 250m east of the Guide Road intersection).
A geotechnical investigation was conducted on the eastern landslide on the 27th of October and the western landslide on the 2nd of November 2022. A public meeting will be scheduled next week for Council Representatives to answer questions regarding the status of the findings to date. Further information will be provide regarding the date and time of the public meeting.
A summary of the engineering investigation are as follows:
Eastern Landslide
The Road has slumped in a section that is approximately 70m long and contain several large cracks. These cracks extend across the entire width of the road and into the natural soils above and below the road. The observations show that the failed section of road has been subject to a previous landslide, and the current failure is a reactivation of the past landslide.
The engineering investigation will continue over the next two weeks to determine the options for this area. The road will remain closed until further information is obtained, on the basis that this area remains a significant safety risk to the public. <_u53a_p>
Western Landslide
The slumped section of road is approximately 125m long and contain several large cracks. This cracking is significant on the downhill side and extends across the entire width of the road. There is evidence of past landslide activity, however no obvious signs of any recent significant landslide activity was observed.
Most recent engineer tests have indicated that there is no significant structural issue with this portion of the road - the council can now look at initial remediation works as follows:
1: Installing appropriate drainage, which involves cutting in channels which will be done using minimal earthworks.
2: Redirection of existing drainage
3: Sealing of the open cracks to limit any further water damage.
<_u53a_p>Once the above has been undertaken, we will consider the reopening of the uphill lane to traffic. The downhill lane will need to remain closed until additional remediation works are undertaken.
Any individual or business impacted by the flood event, including those effected by these road closures may be eligible to apply for Tasmanian Recovery Funding through the Tasmanian Government.
https://alert.tas.gov.au/recovery/
Further engineering information can be found below:
Eastern Landslide
Western Landslide
The intialal remediation works purposed are as follows:
Appropriately drain the depression/gully located above the road. This will require minimal earthworks, involving cutting a channel from the depression to the upper culvert - approximately 10m long and 1-2m deep;