Amber Level Alert as at 14 September 2021
The City will investigate the causes of the elevated levels and increase sampling to enable the risks to recreational users to be more accurately assessed.
View the latest water quality graph(PDF, 457KB).
Lake Hugh Muntz in Mermaid Waters was constructed in the early 1980s as the first lake in the Robina Masterplan. It is about 17 hectares in area. Lake Hugh Muntz was one of the first urban lakes constructed in Queensland.
The lake often has blue-green algal blooms. Some of these algal blooms affect water quality and can be harmful to you. Care must be taken with any intended use of the lake. We conduct regular laboratory testing of the lake water and provide notices via:
- regular updates on this website
- regular updates in our email newsletter
- signs next to the lake.
Email any questions about the lake to firstname.lastname@example.org.
Lake Hugh Muntz newsletter
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Water quality monitoring of the lake and reporting is conducted under the guidelines of the National Health and Medical Research Council (NHMRC).
Red Level Alert
Level 1 guideline: ≥10µg/L total microcystins or ≥50,000 cells/mL M. aeruginosa or biovolume equivalent of ≥4mm3/L for the combined total of all cyanobacteria where a known toxin.
Level 2 guideline: ≥10mm3/L for the total biovolume of all cyanobacterial material where known toxins are not present, or cyanobacterial scums are consistently present.
We will take measures to warn the public that the waterbody is considered unsuitable for primary contact recreation*.
*Primary contact recreation is defined by the NHMRC as 'whole-body contact with recreational activities'. Examples include swimming, snorkelling, children's exploratory activities and wading.
Amber Level Alert
≥5000 to <50,000 cells/mL M. aeruginosa or biovolume equivalent of >0.4 to <4mm3/L for the combined total of all cyanobacteria where a known toxin producer is dominant in the total biovolume or ≥0.4 to <10mm3/L for the combined total of all cyanobacteria where known toxin producers are not present.
We will investigate the causes of the elevated levels and increase sampling to enable the risks to recreational users to be more accurately assessed.
Green Level Alert
≥500 to <5000 cells/mL M. aeruginosa or biovolume equivalent of >0.04 to <0 4mm3/L for the combined total of all cyanobacteria.
We will continue routine sampling to measure cyanobacterial levels.
Swimming at the lake
Lake Hugh Muntz was designed as part of the area's stormwater drainage system, not as a recreational lake. The lake receives runoff from 16 stormwater pipes as well as ground flows. We conduct water quality monitoring regularly and provide health alerts as required.
Safe water quality cannot be guaranteed.
Blue-green algae (Cyanobacteria bloom)
Blue-green algae is a tiny micro-organism that belongs to the cyanobacteria family. The algae can be found in freshwater lake systems when there is an increase in nutrient level, sunlight and stable water columns. Lake Hugh Muntz experiences blue-green algae blooms. To learn more about algal blooms go to Blue-green algae.
You should exercise caution and avoid contact with water:
- where scum or floating debris is visible
- that looks discoloured, murky or smells unpleasant
- near stormwater drains
- for up to 3 days after heavy rainfall
- if you have an open wound or infection.
About the lake
Material extracted from the 17 hectare site was used to build up the surrounding area, providing flood protection for the subdivision. The lake is up to 12 metres deep and has a volume of approximately 280 Olympic swimming pools.
Lake Hugh Muntz is a retention basin for stormwater from 16 pipe outlets. It also receives an exchange of water from the nearby canal. During high tides, this water comes through a pipe under Barrier Reef Drive. More than 4 decades ago when the lake was first constructed, it was freshwater.
During the first decade the lake experienced very low pH. This prevented the growth of aquatic plants in the lake, but the construction of adjacent canal systems changed groundwater in the area from freshwater to saline. This intrusion of saline water helped the system become more pH neutral and aquatic life began to flourish.
Periods of drought have caused water salinity levels to fluctuate. This means that the lake can alternate between freshwater and brackish water (neither saltwater nor freshwater). These changes in salinity can affect aquatic plant growth which is important for water quality.
City of Gold Coast commissioned Griffith University to investigate the use of a one-way valve on the pipe under Barrier Reef Drive as a possible means of reducing inflow of saltwater from the canal system. However, the investigation determined the one-way value would be detrimental to overall water quality as it would create a stagnant environment. Stagnant environments are ideal for blue-green algae growth. Groundwater and water quality monitoring has also proven that tidal canals connect to the lake through groundwater.
The lake's challenges
Lake Hugh Muntz is a dynamic living environment. It has experienced periods of fluctuating water quality including blue-green algal blooms. Therefore, the lake cannot be maintained as a swimming area because water quality cannot be guaranteed.
As with all lakes and waterways in our city, we work to support a healthy ecosystem in Lake Hugh Muntz. There are many factors beyond our control that make it impossible to maintain suitable water quality for such recreation.
These factors include:
- the general design of the lake to depths of up to 12 metres
- the lake receiving inflows from 16 stormwater pipes and urban runoff
- limited tidal exchange
- groundwater inputs
- overland runoff from the surrounding area
- changing and unpredictable climatic conditions.
Due to these factors, maintaining the general water quality of the lake is an extremely complex task. Learn more about who we are working with to take on the challenge.
We only recommend swimming in patrolled beaches, dedicated swimming enclosures and public swimming pools. Miami Aquatic Centre is just a five-minute drive from Lake Hugh Muntz.
Our strategic partner & supporters
We have a proactive approach to addressing Lake Hugh Muntz's challenges.
Griffith University partnership
Our strategic decision to partner with Griffith University enables us to take on the complex water quality challenge at Lake Hugh Muntz. The university's Australian Rivers Institute has investigated options for reducing future algal blooms at this lake, and across our city's other urban lakes.
For more information, visit our Lake Hugh Muntz water quality project page.
A multi-criteria assessment of 31 potential remedial measures to reduce the reach and frequency of algal blooms has been conducted.
Lake Hugh Muntz Stakeholder Group
We actively encouraged community feedback on this popular lake and formed the Lake Hugh Muntz Stakeholder Group 2018. Representatives include:
- Queensland Triathlon
- several Surf Life Saving Clubs
- Merrimac State High School
- Gold Coast Catchment Association
- Healthy Land and Water
- Griffith University
- Lake Hugh Muntz Care Group.
Past mitigation efforts
The City of Gold Coast continues to explore management options to reduce the frequency and duration of algal blooms.
To date, we have trialled several water quality improvement initiatives at the lake, including:
- Installation of 66 gully baskets. These baskets capture 4000 kilograms of organics every year that would otherwise enter the lake. The gully baskets are nets that sit within the stormwater inlets along the kerbside of the roads. They capture leaf litter, soil and other organic materials. City officers maintain these gully baskets at a high frequency. We check and clean them out after rain events.
- Installation of three floating reed beds as an alternative to wetlands, around the stormwater network. The beds are designed to filter out nutrients by using root balls suspended in the water. They have struggled to function effectively within the lake. Restoration of park areas in high sediment zones to reduce runoff into the lake including creating gardens of the native grass Lomandra.
- Installation of five groundwater bores around the lake. This is to help gain a better understanding of groundwater effects on salinity levels within the lake.
Current management plan
The City of Gold Coast continues to work closely with Griffith University and has developed a management plan to optimise a healthy ecosystem at Lake Hugh Muntz:
1.1 Ensure consistent timing of sampling 1.2 Increase sampling frequency from quarterly to monthly 1.3 Consider deployment of two data loggers within 'dead spots' 1.4 Hydrolab DS5X : DO, pH, temp, cond, turbidity, chlo a, blue green algae, depth
|1. Improvement of water quality (WQ) monitoring program
||1.1 Ensure consistent timing of sampling
||Completed, ongoing reviews of the WQ monitoring program have been ongoing
|1.2 Increase sampling frequency from quarterly to monthly
||Medium for consideration
|1.3 Consider deployment of two data loggers within 'dead spots'
||Investigated - under consideration
|1.4 Hydrolab DS5X : DO, pH, temp, cond, turbidity, chlo a, blue green algae, depth
||Investigated - under consideration
|2. Improvements to stormwater quality
||2.1 Provide more rubbish bins in adjacent park areas
||Completed, ongoing maintenance
|2.2 Undertake detailed investigation of stormwater infrastructure and prepare a stormwater improvement implementation plan
|2.3 Prepare the detailed design of stormwater improvement devices as per the recommendations of the stormwater improvement implementation plan
|2.5 Construction of bio retention filters
||Investigated - Not feasible due to numerous constraints including, land acquisition, loss of on street parking
|2.6 Construction of stormwater wetlands
||Investigated - Not a feasible option due to comments from community
|2.7 construction of vegetative swales either in combination with or as an alternative to bio retention filters
||Investigated - Not a feasible option as per the detailed investigation of the stormwater improvement plan
|3. Control of aquatic vegetation and sediment assessment
||3.1 Periodic harvesting of vegetation at entrance points for swimming
||Low: no current need. Review annually as required
||Completed – Ongoing site inspections – harvesting program under review
|3.2 Further benthic assessment investigation of submerged aquatic plant cover and sediment texture
||Medium - High
||Considered – No current aquatic plant cover
|3.3 Bioavailability testing of sediment contaminates*
|4. Control of pest fish populations
||4.1 Bass stocking for control of noxious species
||Considered - Not completed due to lack of available habitat
|4.2 Consider further surveying to confirm species present
||Completed - Some further spot investigations have been undertaken (ongoing)
|5. Control of Algae / Cyanobacteria
||5.1 Undertake a detailed monitoring program for 12 months to define on-going program. Include additional water quality sampling of; algae, chlor-a, nutrients, temp
||Completed – ongoing water quality monitoring program
|5.2 Phoslock trial undertaken in an attempt to improve water quality
|5.3 Data interpretation and sampling re-evaluation
||Completed – ongoing analysis of water quality data
|6. Information transfer
||6.1 Produce and mail out information brochures
||Completed – periodical
|6.2 Maintain updated website
||High: weekly algae report
||Completed – ongoing improvements will be undertaken
|6.3 Construct, design and install information / interpretive display boards in four adjacent parks
||Completed – information sign installed at Bel Air Park
|*Sediment analysis is being undertaken from several locations around the lake.
As part of our decade long program of remedial measures to enhance the lake's ecosystem, we are about to start a new application of Phoslock® across the whole lake bed. Funding of $280,000 has been allocated in the 2021-22 budget for this initiative, with work starting in late July or early August.
In 2018, we conducted a trial application of Phoslock® but it didn't deliver the hoped-for long-term solution for eliminating algal blooms. Over the past 3 years, scientific and practical evaluation of this method offers some renewed optimism but there is no certainty.
Phoslock® is modified bentonite clay. It has undergone rigorous testing by numerous ecological organisations and is certified as safe for humans, animals and the environment. Phoslock® works by binding the nutrients the algae need to grow so blooms are unable to form. It is used in water bodies that have high concentrations of phosphorus.
Dependent on weather and other factors, the application of Phoslock® will occur over a 2-week period. The lake can't be used for recreation purposes during that time. A Phoslock® company representative will be present on site during the application to ensure proper procedures and safety protocols are adhered to.
This initiative will be intensively monitored over an extended period to assess its impact.
Report pollution in the lake
Act now and contact us: