Black Mountain Road
Council is prioritising reconstruction of Black Mountain Road following the landslide to help minimise the impact on Black Mountain Road residents and surrounding communities.
There are three areas of Black Mountain Road in need of reconstruction, however the landslide near Eungella Drive - which has cut the road access - is a very serious landslide.
Initial geotechnical engineering reporting indicates that this is the most significant landslide to affect a road asset in the Noosa and Sunshine Coast region in the last 30 years. It is noted as being approximately 120 metres wide and approximately 15 metres deep. While it may look as though the top could be easily repaired - when viewed from above - the depth of the slide, along with the soil structure and water content, make it a very complex situation.
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Council has requested reconstruction funding, in excess of $25 million, through the Disaster Recovery Funding Arrangements (DRFA). Council has worked closely with Queensland Reconstruction Authority (QRA) - the agency that manages DRFA requests - to develop a plan to reconstruct this road.
As the significant reconstruction costs might suggest, this will be a vastly complex construction project and one that is unlikely to be completed until 2024. A staged reconstruction process is proposed. Below outlines these phases, to help explain the completion date of 2024.
Current Plan for reconstruction
The following outlines the plan for reconstruction.
Phase 1 – Geotechnical engineering
Status: The geotechnical engineering has been completed but monitoring will continue.
Geotechnical work to assess the slope stability is an essential part of determining the plans for reconstruction. Making sure the foundation beneath the landslide is stable is the key to preventing future similar failures to occur. Geotechnical investigation of slope stability is a staged activity. Stage 1 is a preliminary assessment and was conducted several months ago, which is when Council closed the access to the site.
Stage 2 of the geotechnical engineering, which involves the boring of holes to investigate what is occurring below ground, will continue but the current reports have confirmed the significant nature of the landslide. The level of reconstruction required means likely completion won't be until 2024. There is also some further technical information in the FAQ section on this page.
Experts have advised that the unformed pathway across the landslide site is NOT safe for use. Any use will be by authorisation only and will be typically for reconstruction purposes only.
Phase 2 – Funding Submission
Status: This submission has now progressed to the approval phase and remains subject to final QRA endorsement.
In consultation with QRA, Council has already sought approval for a likely solution, based on the geotechnical advice and that of experienced civil engineers.
QRA will assess this submission and work with Council to fund the next steps of the design, approval and construction phase.
Phase 3 – Design
Status: Council has now awarded a contract to a supplier who is working on the concept designs.
As this will require a complex construction solution, the concept design is essential to ensure a detailed design can be created for development of the construction plan and a tender for the $25 million works that are needed to reconstruct the road.
Council will communicate with the community about the progress of the design. The concept phase is expected to be completed by the end of September 2022.
Phase 4 – Environmental Assessment
Status: Environmental assessment will be an outcome of the final design.
Council is responsible for, and committed to, maintaining and enhancing the Shire’s natural environment. All work Council undertakes requires the necessary approvals under the Queensland Environmental Protection Act. This is to ensure any impacts to residents or the environment are considered and can be minimised prior to construction commencing.
Phase 5 – Construction
Status: Construction works will commence when a final design is approved.
A typical construction process to fix a landslide such as this would involve site establishment, upslope stabilisation, excavation of the area, foundation works, structural works, earthworks, drainage, road sub-base, pavement, line marking and other road safety infrastructure.
At this stage, without an accepted design, it is difficult to be exact on the time required to complete these works as it is dependent on the design, contractor and the materials available.
This page will be regularly updated to keep the community informed of the most current work.
Black Mountain Road Project News
Frequently asked questions
The landslide has several modes of movement which include a very large, deep-seated section as well as localised, shallow debris flows. Groundwater and surface water have created saturated zones, and therefore we can still see water flowing from the site. The site continues to move in some places and is not stable enough for any type of unauthorised access across any section of the closed section.
The image below illustrates a cross-section of the landslide.
- BH7, BH8, BH9 (Borehole sites) shows the depth of the sensing equipment that monitors the depth of movement
- The large dotted red line shows the movement in the deeper part of the landslide. This is the section we cannot see.
- The smaller dotted red lines and blue arrows show the shallower landslide section which has resulted in the ground slumping you can see at the surface.
The solution will require a multifaceted and robust solution that considers the soil, structural and drainage needs. This type of work is complex and very specialised contractors will need to be engaged to do this. It is also necessary that bulk of the work be completed during the dry seasons of the year, which is contributing to the length of time for the planned reconstruction.
Council will make the most of any opportunity available to accelerate this reconstruction period.
Important points to know:
- The site is still unsafe so please do not go to the site. Please do not use the unmade track across the top of the landslide. It is for authorised use only, such as by engineering and construction contractors.
- The solutions are complex and require planning to ensure specialised design and construction so as to minimise the possibility of any further issues in the future.
Due to the landslide, the section of road between Eungella Drive and private access Leilani Lane has been completely closed to traffic and pedestrians. There is also signage indicating the road is closed to all except local residents. This is for your safety and the safety of the residents.
To access homes and businesses on Black Mountain Road, you will be able to enter and exit using Andersons Road via Middle Creek Road. Detour signs are now in place on major connecting roads along with recognition on online maps.
To accommodate increased traffic using the western end of Black Mountain Road and Andersons Road, the following actions have been taken:
- Road widened to allow for safe vehicle passing in opposite directions
- Road graded to improve road surface
- Roadside clearing in areas to allow for vehicles to pull off the road or allow vehicles to turn around
- Andersons Road crossing at Slate Creek now has a temporary crossing that increased the height for better resilience during rain events.
- Andersons Road crossing now has sensors linked to the Noosa Disaster Dashboard to inform them of road crossing status during rain events.
Council continues to monitor the state of this thoroughfare and is working through plans to program ongoing maintenance. Staff are also in discussions with QRA about what other resources are available to support the ongoing increased use of this road.
Black Mountain Road residents' access to services will continue in the following manner:
- Prior to the landslide the road was maintained annually. With the increased use, Council will now maintain it more frequently, based on usage and weather.
- For safety reasons, residents will need to continue to place rubbish at the designated area near the corner of Black Mountain Road and Andersons Road.
- Council and the waste contractor have investigated a range of proposals for reinstating waste collection but there are no fair and safe options that are feasible. See the FAQ on Waste for more information. Council will continue to investigate solutions to reduce this inconvenience.
- Council current ly offers Council Cabs to eligible members of the community. Find out more
- Council has also confirmed with Translink that school transport options have been offered to families with school aged children. Council again reiterates nobody is permitted to enter the landslide site unless authorised.
- Australia Post has resumed services, which are likely to be impacted only when the road is affected by rain events.
- Courier services should be able to continue as before as the most frequently used online mapping has been updated.
- As there are no load restrictions for Andersons Road or Black Mountain Road, most services should not be affected.
- The contractor should conduct their own safety assessment of the location they are to deliver to and the route they take to ensure they can safely do so.
Prior to the landslide, residents from Enugella Drive to Crawfords Road received a roadside waste collection service. Residents beyond this point used the designated rubbish corral area near the Black Mountain Road and Andersons Road intersection. The waste trucks have never entered the eastern section of Black Mountain Road from the Andersons Road end due to safety issues. The impact of the landslide and having additional traffic on this section, only further increases the safety concerns around waste trucks on this section of road.
Council has explored several options including different types of trucks, road upgrades and traffic management. All of these are not feasible due to ongoing safety concerns and/or the need to close the section of the road for an unacceptable period of time.