Please see the latest water quality results courtesy of GCCC.
GCCC are requesting all residents to have their say on how Councils spends its 1.5 Billion dollars by completing a survey online.
In question 4 the survey asks;
“If you could fix one local issue what would that be?”
This is a great opportunity to highlight the need to “fix” Lake Hugh Muntz so could you please take time to fill in and prioritise what you want funds spent on in your local area!
Unfortunately a group of youths managed to overturn the water quality monitoring station on Friday.
Local residents called Police and at this stage it is unknown whether charges will be laid. Apart from serious damage to the electronics, water quality measurements are now indefinitely interrupted until the damage is repaired. The monitoring platform was recovered by Council workers on Saturday. It is important that users of the lake STAY OFF THE PLATFORM! This is not designed as a rest stop for SUP’s or as a diving platform!
Brisbane Council Plan to Implement Aerators in Forest Lake: Why isn’t the Gold Coast CC exploring this option for Lake Hugh Muntz?
Forest Lake is a freshwater lake, located approximately 20 km from the Brisbane CBD, and has a lot in common with Lake Hugh Muntz in Mermaid Waters on the Gold Coast.
This non- swimming lake is about two thirds the size of LHM and has also been battling with Blue Green Algae for many years.
Forest Lake is situated in a highly built up area, surrounded by many properties that are directly affected by the ongoing decline in lake health.
Like LHM, Forest Lake has experienced delays in finding and implementing effective treatment. This has resulted in a further decline of water quality, an increased difficulty in finding a resolution, along with increased maintenance costs.
The similarities end here.
Brisbane City Council (BCC) have a “ Management Plan” and an approved budget of one million dollars to implement effective trials to combat the algae. This is on top of the fifty thousand dollars that BCC has spent on lake maintenance every year.
Please see link below to a video for more info on the trial of bottom aerators as the first step in lake restoration
Floating Black Deposits have been reported in several areas on the Eastern side of the lake in front of properties and parklands. Similar deposits have surfaced in the West side of the lake in the past. The West side of the lake is in a critical condition – no oxygen at the lower levels contributing to a build-up of decaying material.
To date, there has never been a reported occurrence in the Eastern lake. Clearly this cannot be seen as a positive indication.
Council advised that the black spots were collected by CMU and have been identified as decaying organic matter. Council has indicated that these types of ‘black spots’ occur routinely across most old lakes.
Please see the info below courtesy GCCC. “Hotspots” for algae included in image below;
Recent water quality testing undertaken within Lake Hugh Muntz has indicated an increase in Algae Biovolume. The most recent graph and further information can be found on the City’s Lake Hugh Muntz Website.
The recent hot weather is not helping and is most likely the cause of the sudden spike in algal biovolume. A possible reason for two locations having higher biovolumes could be attributed to windblown algal accumulating at these locations.
Next sampling will be undertaken on Tuesday 29th January 2019 for cyanobacteria identification and biovolume.
The “Study of Management Options to Mitigate Algal Blooms” in Lake Hugh Muntz has been made available to the public.
The report from the Griffith Uni Experts released to GCCC in August last year can be viewed on GCCC website on the Lake Hugh Muntz page through the link below.
In Summary, the short term solution is to manage the blooms through treatments such as Phoslock and hydrogen peroxide. Unfortunately GCCC do not currently have equipment to treat with hydrogen peroxide. Computer modelling has indicated that the installation of Aerators would give the best result in reducing algal blooms.
Some Statements Taken from the Report
Our report does not provide any additional information on catchment management options because its purpose is to review and propose in-lake options for managing algal blooms. However, we note that ongoing evaluation of stormwater volumes and nutrient loads is required and that the success of these will determine the longevity of in-lake management options.
Conceptual models showing the state of the lake in 2008 (Management Plan), and a scenario of a transition to a eutrophic system highlighted the potential outcomes that could occur with continued excess nutrient inputs, such as algal blooms and fish kills. It is clear that some of the anticipated issues identified in 2008 have come to eventuate in 2018 and that more active management intervention actions are required.
Computer Modelling showing aeration giving the best result in Algae reduction. (green Line)
Water quality of Lake Hugh Muntz has deteriorated markedly over the past 15 years.
Once management actions are adopted at the whole lake scale, an idealised scientific approach of a single action followed by observation(s) is not generally possible or desirable, and the approach should be to adopt multiple management actions concurrently. For example, if a geoengineering material (Phoslock etc) was applied within the lake, then catchment management actions should be adopted concurrently, to maximise the duration on which the geoengineering treatment was effective.
- In the shorter term, managing blooms using interventions within the lake is likely to be the most cost-effective option. Our lab analyses showed positive effects, both for the application of hydrogen peroxide and PhoslockTM but other chemicals (e.g., PAC) may have complementary effects related to additional inactivation of phosphorus.
- It is important to note that the application of hydrogen peroxide is only an intermediate solution and will not solve the underlying cause of cyanobacteria blooms (i.e., the combination of high nutrients and the shallow freshwater lens in the lake). Simulation scenarios indicated that complete overturn of the water column through installation of a bottom aerator (i.e., artificial destratification) was the most effective remediation method but it is very expensive and would elevate nutrients and salinity in the surface water layer as well as maintaining particulate material in the water column for longer periods of time. This technique may result in little change in water quality although it would reduce the incidence of surface blooms.
For immediate action, we recommend:
- initiating mesocosm experiments in the field, trialling the effectiveness of hydrogen peroxide and PhoslockTM under natural conditions. This will then demonstrate whether hydrogen peroxide is effective for C. ovalisporum at concentrations tested in the laboratory and minimising the effect on other algae and animals. Additionally, Phoslock trials will test how effectively the compounds reduces phosphorus concentrations in the water column, and caps the sediment.
- water quality model runs to test adequate dosages and timing of application to avoid spending unnecessary resources and/or achieving sub-optimal results.
- laboratory measurements to better understand the growth requirements and toxin production of C. ovalisporum isolated from Lake Hugh Muntz. This is a poorly studied species so the literature is not helpful for the modelling questions. Additionally, the isolates Lake Hugh Muntz will be locally adapted to specific salinity, temperature, light and other conditions. This information is crucial to effective modelling.
Signs below have just been placed around the lake indicating closure of the lake again!
Prior to the recent Phoslock treatment in early December, algae readings were increasing indicating the start of yet another Algal bloom.
With the previous closure lasting 9 long months the BIG question is how long will the lake be closed this time?
Only time will tell if the Phoslock trial will reduce the length and severity of the current algal bloom.
Despite Councils Action Plan Timeline indicating the revision of the Management Plan in November there is still NO plan on how Council intends to address the long outstanding water quality issues.
Have received information from Council that recent water quality testing undertaken within Lake Hugh Muntz has indicated an increase in Algae Biovolume. Council is currently testing the water on a weekly basis.
This information is in line with the current observations of reduced water clarity and the lake turning a green/brown colour. Will provide further updates on progress when received.