The Lake King project will action critical dam safety and landscaping works leading to the overall enhancement of the Lake King recreational area, including improvements to pathways and connectivity to the town centre.
View a drawing of the Lake King project here(PDF, 4MB).
A contract has been awarded for the civil works component of the Lake King remodelling project with works expected to commence on site in the first week of February.
The Lake King re-modelling project is major component of the Rutherglen Economic Revitalisation Project. The Lake King project will action critical dam safety and landscaping works leading to the overall enhancement of the Lake King recreational area, including improvements to pathways and connectivity to the town centre.
Following the community drop in sessions held in late November Council advertised a tender for the civil earthworks component of the Lake King remodelling project. These submissions were evaluated this month with a tender accepted from Walsh Wodonga Pty Ltd.
Walsh has a proven track record completing similar works and we are very excited about the experience and expertise they bring to the project and their availability to commence works in early February 2019.
Development of the detailed project plan and methodology is underway but will be completed in consultation with the Department of Environment, Land, Water and Planning (DELWP), who manages the land, Council who are managing the project and the other key stakeholders around the Lake.
Works can be expected to progress generally in the following stages:
Contractor to set up temporary compound/site offices between dam wall and Murray St in the cleared area to the West of the Bowling Club. Anticipated to commence Monday 4 February.
Soon after this the boundary fencing (para-webbing) will be erected around the whole site to define the working area and close it to the public. The dam wall walking track will remain open for as long as possible until actual works commence with Murray St providing a temporary alternate route thereafter.
In order to allow the dam wall to be lowered the trees and other vegetation upon the dam banks, and in the spillway area to the west of the Bowling club will need to be removed.
It is expected that some of the established vegetation on the dam wall facing the bowling club greens will be able to be retained due the lesser extent of dam lowering in that location.
The existing viewing platform, constructed by Rotary, will be carefully removed and stored on site for refurbishment and re-installation at the end of the project in its current home.
The bulk earthworks will then commence in carefully managed stages to complete the overall lowering of the dam wall and remodelling into the new landscape.
Construction of new underground drainage outfalls, a concrete spillway, gravel pathways and a new sandy recreation beach area are all part of the proposed improvements within this contract.
The contractor has nominated an approximate 10 week timeline for completion of this civil works contract which will lead the way to allow final landscaping and plantings to be completed in May-June. It is hoped that the Rutherglen community will respond to calls for assistance near this time in helping to complete the extensive planting component of the project. We are grateful for those already having expressed their interest at the drop in sessions.
November 2018 saw Council's project officers hold 2 drop in sessions at the Rutherglen Bowling Club. The drop in sessions were an opportunity for the public to view project plans and provide feedback.
The following points were raised at the community drop-in sessions and are still being evaluated:
There was some interest in the reinstatement of the fountain which previously operated in the lake. This was not in the initial scope of works but we are still exploring what could be done to potentially re-activate this.
Council will involve the local community in selecting the locations for new seating once the final landscaping stage is underway.
Dust and noise control
Whilst the extent of earthworks involved is considerable Councils contractor will ensure works are kept within approved times and dust control is addressed as much as practically possible. The methodology adopted by the contractor will ensure that lake water is retained on site during the project for environmental and dust suppression purposes.
Why does the lake have to be modified?
A Hydrology Study and Consequence Assessment conducted in June 2013 determined that the dam wall was unsafe and posed a risk to infrastructure, property and to the Rutherglen community. The study concluded that:
Lake King either be decommissioned and converted into a wetland or water feature or,
Remedial works be carried out to the Dam wall to make it safe and compliant with ANGOLD Guidelines.
The option to remediate and strengthen the dam wall required the relocation of the Rutherglen bowling club and predicted that the capital costs would be in the order of $10 million dollars.
The option to convert Lake King to a wetland was selected to both enhance and better activate this recreational area in a cost-effective way and mitigate the risks to the Rutherglen Community.
Where was the dam wall leaking?
Several seepage areas have been identified within the vicinity of the Rutherglen Bowls club towards the eastern end of the dam wall. The leaks were identified in 2011 and are believed to be as a result of vegetation planted on the dam wall, additions of spoil to the dam wall and from an old decommissioned cast iron outlet pipe.
What is the current risk to the community from Lake King?
Risks from dam leakage were significantly reduced following the installation of an outfall drain in 2014. The immediate effect was to lower the maximum water level and reduce the volume of water that could be retained by the dam wall. There is however still a residual Dam safety risk to be minimised to within ANCOLD guidelines by lowering the NWL to 168.00 with a maximum spillway level set at 168.30.
Will the proposed works increase the potential for flooding of Murray Street?
The conversion of the Lake will reduce the potential for the lake to flood Murray Street.
When will the construction works commence?
Bulk earthworks and final landscaping expected to commence early in 2019 for completion by mid-year.
What should we generally expect to see as works progress?
Effectively the project will lower the height of the dam wall to varying degrees along its current length and place this material back in and around the lake to create the new landscape features. In general terms the dam wall will be lowered approximately 1.5m immediately behind the Bowling club and at least 2.5m either side of this. A new concrete spillway/footpath will be created at the Western end which will take any overflow through a wide grassy channel into the drainage system.
What is the design level of the proposed water body?
The normal top of water level (NTWL) has been designed to 168.00 AHD. This is the water level that has been determined to be sustainable on a long term basis. 168.00 is approximately 0.5m above the current water level as at 2 November 2018.
Will the water body dry out more often once the works are complete?
The results of hydrological calculations based on historical data indicate that the wetland will have water in it 90% of the time with the new design normal water level of 168.00 being achieved about 65 per cent of the time.
Those calculations also indicate a more stable level in the wetland, particularly when compared to the fluctuations in water level experienced historically.
How deep will the water body be?
The proposed remodelling works will not excavate below the current level of the base of Lake King, based on advice DELWP received following the Dam safety assessment. The remodelled water body will have varying depths, up to maximum of 1.5m for the NWL of 168.0. The maximum depth will increase to 1.8m at times of peak inflows.
The deeper and shallower sections maximise habitat opportunities and water quality within the waterbody. The shallower areas with depths of around 300mm within the wetland areas will eventually be planted with specially selected species.
How will fishing be impacted by the new water body design?
The design of the remodelled water body incorporates opportunities to create habitat for fish and access to the deeper parts of the water body for angles in the future. Council has noted the community’s request to the stocking of the water body with native fish and conveyed these requests to DELWP, who retain the ultimate management and control of the Lake King reserve.
What is the volume of water in Lake King?
The current capacity is approximately 31.5ML following the installation of the outlet pipe in 2014. The reduction of risk to dam safety requires the remodelled water level to be reduced so that the maximum volume contained in Lake King is reduced to 20ML.
How will the works impact the local wild life?
Initially the works will create a disturbance for wild life. To help mitigate disturbance to local fauna consideration will be given to the timing and staging of the construction works to minimise disturbance during breeding seasons. However, the remodelled water body and adjoining environs will create greater habitat diversity and opportunity for local wild life once fully established.
What are the benefits to the local community of remodelling Lake King?
The remodelling of Lake King has the opportunity to provide many benefits to the local community. Some of the key benefits are as follows:
- Improved visual amenity
- Designed to remove expanse of ‘bare clay’ areas around the wetland edge
- Greater visual and physical connection with the surrounding landscape, particularly with Murray Street.
- Improved habitat opportunities for local fauna
- Greater vegetation diversity
- Improved pedestrian links and circulation
- Opportunities to work in with local arts community
- Increased patronage of the immediate and local area
- The creation of a safe user friendly asset for the community
Can the community get involved in the landscaping?
A major component of the finished project will be its re-vegetation once completion of the bulk earthworks and landscaping are completed. This will be timed to be completed during the preferred planting seasons after summer. There is the potential for interested community members to register their interest in assisting Council officers in this planting process at the appropriate time to help kick start the development of this important asset.