Council has decided to move forward with a new swimming enclosure for Wallaroo.
The project was originally planned for the 2017/18 financial year with final plans to be completed during 2016/17.
Those plans were changed by Council following the May 2016 storms, with Council now attempting to have a replacement completed by Christmas this year.
Following a Council meeting decision to look at options for the site, the public consultation has resulted in a final plan being developed. That plan was approved by Council on the 22nd August 2016.
In the initial scoping design we thought that a similar net arrangement to Port Lincoln would work in our location. However, further research and practical advantages have deemed that the best option is to include in stage 1 a system of floating attenuators and nets separate from the pontoon structure. This will increase the available safe swimming area and reduce the amount of wind chop experienced by the users of the facility.
Shade was another issue highlighted through the public consultation. Additional piles in stage 1 (while the piling equipment is mobilised) to accommodate shade cloth is the most economical way to meet this request from the public.
DDA access ramps into the enclosed area instead of the proposed steps added to the design and construction costs. The angle of the access platforms has also been improved, by increasing the lengths slightly.
Feedback from the community supported the small area for learn to swim. This has increased the number of pontoons, but overall it provides a greater usability for a broader range of our community.
However, while the scope between stage 1 and 2 has altered the overall project is still achievable within the original total planned budget.
Figure 1 - Pontoon Plan
There were two comments from the public regarding the location of the facility, their desire was for it to be located more to the west, closer to the current swimming enclosure location.
The location with the access platforms straddling the viewing platform has been selected for a number of reasons including;
- The depth of water, any further to the east and the water gets too shallow.
- The waves are more consistent and uniform than to the west where the larger jetty causes disruption to the wave formations.
- The location allows for the attenuators and nets to sit well away from the floating structure. If the structure was located more to the west, the nets would be restricted by the Flinders Ports jetty and the access ramps would therefore be directly in front of the café.
- This location allows for easy viewing and access off the lawn area.
Figure 2 - Location Plan
There has also been concerns about the structural integrity of a floating structure in an area that is open to storm events, especially after seeing the power of the wave action and storms during May 2016.
This is also the staff’s greatest concern and there are no guarantees because engineers, like any of us, can get it wrong. Therefore we have undertaken the following to ensure that we have a greater level of confidence in the proposal, although there can never be certainty.
- Collected wave data
- Undertaken geological testing
- Wave and load analysis
- Consulted with two engineering organisations – Meinhardt and Magryn
- Discussed the proposal with other industry competitors and previous SeaSlip customers.
- Requested 25 plus years for the design life with a safety margin for unknowns to be built into the design. i.e. planned for the worse case scenario
- Not removed any factors from the budget that could affect safety or longevity of the design.
- Positioned the structure in the best possible location and away from the rebound waves off the seawall.
Seaslips summary of their final proposal is as follows.
“Seaslip , through the Meinhardt Engineering Group, Sydney, and Magryn & Associates Coastal Engineering Group SA advise that all necessary site investigations have now been completed and we are confident to confirm that the final facility proposed in this submission has been designed and will be constructed to all engineer requirements.
Our pricing reflects these requirements for the sustainability and longevity of the facility to endure the conditions it will be subjected to in this location .”
In summary, this infrastructure is critical to both the local residents and the tourism industry. While it is duplicated in Moonta Bay, the Wallaroo area relies heavily on this structure for both local enjoyment and as a tourism product. If we can proceed now, it is still a viable option to have it completed by early December 2016.
Further background provided is available in the 20th June 2016 Council Agenda.