Complete an online Feedback Form
- Complete an online Feedback Form
OR
- Complete a paper copy Feedback Form (available at West Lakes Library).
The same questions are asked in both versions.
Project Background
Review, refresh, renew and reimagine (December 2021)
In December 2021 we announced that we were soon to commence a review of the way Freshwater Lake (also known as the Delfin Island duck ponds) on Delfin Island at West Lakes operates and exists. Freshwater Lake is located within Freshwater Lake Reserve.
As that time we explained that no investigations or decisions have been made on the Lake’s long-term future.
Freshwater Lake was constructed in the 1970s as a key water feature of the West Lakes Delfin Island Development. It was built to the standards of that era and now requires a high level of ongoing maintenance due to its unique design, structure and age.
Given the high level of ongoing maintenance needed and the resources this requires it is important we take some time to review how we are managing Freshwater Lake now and into the future.
This review commenced in March 2022 and included two steps:
- Investigations and management considerations for the lake; and
- First stage of community engagement.
This information will inform Council's decision making regarding Freshwater Lake.
Original Options (March 2022)
Originally four options were identified within the scope of the review. We explained that it was too early to say exactly which options might be feasible and that community sentiment and engineering advice would help develop options.
(Note: Options 3 and 4 are no longer being considered).
This option proposes to continue to operate Freshwater Lake as we currently do. This option requires the lake to be drained and de-sludged (de-watered and cleaned). The desludging operation is conservatively estimated to cost around $600,000 . This desludging operation is an ongoing requirement of lake management (approximately every 10 years).
De-sludging is necessary to remove the build-up of nutrient containing sediments and improve the overall water quality of the lake. As sludge builds up over time, it reduces the amount of water above this sludge layer, making the water body above more shallow and more prone to warming and greening.
Desludging alone will not provide a permanent improvement to water quality. It will provide a limited improvement for approximately 5-10 years, depending on the prevailing conditions.
This option does not address lake seepage (leaking), water circulation issues, high evaporation, treating the bottom of the lake to make future de-sludging easier and more effective, or reviewing the source of water for filling the lake (currently drawn from groundwater).
This option proposes to continue to operate Freshwater Lake as we currently do but with improvements to permanently enhance lake performance and quality, operations and management. This option requires the lake to be drained and de-sludged. The desludging operation is conservatively estimated to cost around $600,000. This desludging operation is an ongoing requirement of lake management and with improvements to lake performance and quality, operation and management, this may occur less frequently than every 10 years.
De-sludging is necessary to remove the build-up of nutrient containing sediments and improve the overall water quality of the lake. As sludge builds up over time, it reduces the amount of water above this sludge layer, making the water body above more shallow and more prone to warming and greening.
Desludging alone will not provide a permanent improvement to water quality. It will provide a limited improvement for approximately 5-10 years, depending on the prevailing conditions.
Maintaining the lake in its current form but with improvements to permanently enhance lake performance and quality, operations and management will also need to consider:
- Means of making long-term improvements to water quality and fix the leaks to the lake.
- Treating the bottom of the lake to make future de-sludging easier and more effective.
- Addressing poor water circulation.
- Reviewing the source of water for filling the lake (currently drawn from groundwater).
- Managing aquatic plant and animal life, including controlling carp.
This option would explore and examine a differently-engineered lake, or a vegetated wetland, or a series of smaller water bodies with bigger green areas or reducing the overall lake “footprint”.
This option would look at:
- Changes to the lake design and structure and re-engineering required.
- Means of making long-term improvements to water quality and fix the leaks to lake.
- Treating the bottom of the lake to make future de-sludging easier and more effective.
- Addressing poor water circulation.
- Reviewing the source of water for filling the lake (currently drawn from groundwater).
- Managing aquatic plant and animal life, including controlling carp.
- Considering the design opportunities for the open space created by reducing the lake area, shape or size.
This option proposes to remove the water body and make the entire reserve terrestrial (land-based) open space.
This option would look at:
- Decommissioning the lake and the engineering and environmental processes involved in doing so.
- Considering the design opportunities for the open space created by removing the lake area.
- Developing concepts for the creation of higher amenity open space (“botanic-garden style”) that could be used for a range of purposes such as weddings, environmental education, picnics, play, respite and reflection.
First Stage of Community Engagement (March 2022)
In March 2022, we invited our community to tell us what they love or would like to change about Freshwater Lake. The purpose of this first stage of community engagement helped establish community sentiment for Freshwater Lake.
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Tell us what you love about the Lake
Scroll down to the question in the blue box and tell us what you love or would like to change about Freshwater Lake.
You can also add comments to what other members of our community have written.
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Click on the + Follow button
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What does Freshwater Lake mean to you? (March 2022)
Consultation on options is planned for mid 2022, in the meantime we would like to gather your thoughts about Freshwater Lake (comments can be about the lake and the reserve generally).
Post your comments, pick a category and add your comments (don't forget to say why this is important to you). Your can also add a photo or short video. Here are the four categories:
- What I love about Freshwater Lake Reserve.
- What I want to see more of at Freshwater Lake Reserve.
- What I want to see less of at Freshwater Lake Reserve.
- What I want to change about Freshwater Lake Reserve.
To get you started, here are a few examples:
- I love watching the ducks swim around the lake, it is so relaxing.
- I want to see more shade trees in the reserve as this will make the area feel cooler.
- I want to see less algae in the lake, this will help reduce the smell.
- I like to picnic in the park with my family.
Add as many comments as you wish, and you can also 'like' or comment on other people's posts.
Your comments will be considered in the development of options.
This activity was open until 31 March 2022.
View the community sentiment gathered online in the first stage of community engagement.
Freshwater Lake - much loved by our community (June 2022)
In March 2022 we asked our community what they love, or would like to change, about Freshwater Lake. Feedback received through this first stage of the Community Engagement has identified a strong community preference for the retention of Freshwater Lake.
Of the 632 residents who submitted a feedback form, 96% wish to keep Freshwater Lake in its current form.
Feedback has identified that any option to change or reduce the size of the lake or eliminate the water body completely was not supported by our community.
Focus on options that keep Freshwater Lake (June 2022)
Given the strong community support for Freshwater Lake, Council responded and refined the scope of the review to the two options that retain the lake in its current form.
Other options have been removed from the scope.
This option proposes to continue to operate Freshwater Lake as we currently do. This option requires the lake to be drained and de-sludged (de-watered and cleaned). The desludging operation is conservatively estimated to cost around $600,000 . This desludging operation is an ongoing requirement of lake management (approximately every 10 years).
De-sludging is necessary to remove the build-up of nutrient containing sediments and improve the overall water quality of the lake. As sludge builds up over time, it reduces the amount of water above this sludge layer, making the water body above more shallow and more prone to warming and greening.
Desludging alone will not provide a permanent improvement to water quality. It will provide a limited improvement for approximately 5-10 years, depending on the prevailing conditions.
This option does not address lake seepage (leaking), water circulation issues, high evaporation, treating the bottom of the lake to make future de-sludging easier and more effective, or reviewing the source of water for filling the lake (currently drawn from groundwater).
This option proposes to continue to operate Freshwater Lake as we currently do but with improvements to permanently enhance lake performance and quality, operations and management. This option requires the lake to be drained and de-sludged. The desludging operation is conservatively estimated to cost around $600,000. This desludging operation is an ongoing requirement of lake management and with improvements to lake performance and quality, operation and management, this may occur less frequently than every 10 years.
De-sludging is necessary to remove the build-up of nutrient containing sediments and improve the overall water quality of the lake. As sludge builds up over time, it reduces the amount of water above this sludge layer, making the water body above more shallow and more prone to warming and greening.
Desludging alone will not provide a permanent improvement to water quality. It will provide a limited improvement for approximately 5-10 years, depending on the prevailing conditions.
Maintaining the lake in its current form but with improvements to permanently enhance lake performance and quality, operations and management will also need to consider:
- Means of making long-term improvements to water quality and fix the leaks to the lake.
- Treating the bottom of the lake to make future de-sludging easier and more effective.
- Addressing poor water circulation.
- Reviewing the source of water for filling the lake (currently drawn from groundwater).
- Managing aquatic plant and animal life, including controlling carp.
Recent action and next steps (June 2022)
We have now considered engineering options and community sentiment, and we are the next stage of engagement on future options will start in late July 2022.
Three options for Freshwater Lake (August 2022)
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Option 1 - Existing system
Maintain the lake in its current form and continue with existing maintenance and management practices.
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Option 2A - Off-line treatment
Maintain the lake in its current form with structural & management improvements to permanently enhance lake performance and quality, operations, and management.
This option involves off-line water treatment where water is circulated out of the lake into a bioretention system and treated using a filter media, plants, and other biological processes external to the lake water body and then the water is recirculated back into the lake.
Possible methods: biofiltration system or connection to wetlands.
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Option 2B - In-line treatment
Maintain the lake in its current form with structural and management improvements to permanently enhance lake performance and quality, operations, and management.
This option involves in-line water treatment where water is treated in the lake using plants and other biological processes in a wetland/reedbed system within the lake.
Possible methods: floating wetlands and reedbeds in Freshwater Lake.
Look at the options and complete our survey (August 2022)
- Read the Information Sheet, Options Comparison Tables and background technical reports available at:
- Document library on this page;
- Front Counter, City of Charles Sturt Civic Centre, 72 Woodville Road, Woodville;
- Ngutungka West Lakes (Council's new library & community hub), 9 Charles Street, West Lakes;
- Bower Cottages Community Centre, 200 Bower Road, Semaphore Park;
- Seaton North Neighbourhood Centre, 16 Cairns Avenue, Seaton; and
- Council's Mobile Library.
- Attend our community drop-in information event on Saturday 13 August 2022 at Ngutungka West Lakes, Drop in and chat with members of our project team anytime between:
- 10.30am and 12.00pm, or between
- 1.00pm and 2.30pm.
- Complete the survey below by 5.00pm, Monday 22 August 2022 (if you prefer you can print this hardcopy survey, pick up a survey form from the locations listed above, or call Council on 8408 1111).
How do the options compare? (August 2022)
We have summarised the technical reports to compare the options. Table 1 below provides a comparison of options against the principles and Table 2 looks at the similarities and differences between the options. For further details refer to the technical reports located in the document library on this page.
Table 1
Table 1: Comparison of options against principles
| Future Option | Reset lake water quality | Remove carp and enhance biodiversity | Remove sludge | Secure and maintain water supply | Reduce water losses | Improve water circulation and increase lake water turn over | Develop an effective and sustainable water quality treatment process |
| Option 1: Existing system | YES | YES | YES | YES | NO | NO | NO |
| Option 2A: Off-line treatment | YES | YES | YES | YES | YES | YES | YES |
| Option 2B: In-line treatment | YES | YES | YES | YES | YES | YES | YES |
Table 2
Table 2: Side-by-side comparison of options
| Considerations | Actions | Option 1 Existing system | Option 2A Off-line treatment | Option 2B In-line treatment |
| Water quality | Optimises water quality and water turnover | NO | YES | YES |
| Water circulation | Improves water circulation | NO | YES | YES |
| Water conservation | Reduces water loss | NO | YES | YES |
| Sludge removal frequency | Reduces need to drain and remove sludge from the lake | NO | YES | YES |
| Sludge removal interval | Years before sludge removal may be needed again | 5-10 years | 20-30 years | 10-15 years |
| Biodiversity | Improves aquatic habitat | NO | YES | YES |
| Biodiversity | May increase numbers of birds on site including ibis | NO | NO | YES |
| Biodiversity | Removes carp | YES | YES | YES |
| Biodiversity | Keeps existing desired flora and fauna such as turtles and waterlilies | YES | YES | YES |
| Changes to water views | Maintains existing open water views of the lake | YES | YES | NO |
| Changes to water views | Offers a mix of wetland and open water views of the lake | NO | NO | YES |
| Changes to water views | May obscure or block current water view from some properties | NO | NO | YES |
| Appearance of lake environs | Changes the look of the lake by introducing either reedbeds or floating wetlands | NO | NO | YES |
| Protection of plantings during establishment period | Plants will be protected by netting for 12-18 months to prevent grazing by birds during establishment | Not required | Not required | YES |
| Energy efficiency | Improved energy efficiency | NO | YES | YES |
| Lake management | Reactive management of water quality | YES | NO | NO |
| Lake management | Planned and proactive management of water quality | NO | YES | YES |
| On-site works required | On-site works (e.g. install pipework, drain lake, remove sludge and carp) | YES | YES | YES |
| Equivalent annual costs averaged over 30 years | Costed on WGA report only using 2022 costs | $421,800 average pa | $366,400 average pa | $377,900 average pa |
