Aspendale Beach. Source: EPA Victoria
The beaches around Port Phillip Bay are used for recreational activities such as swimming and boating, particularly throughout summer.
Environment Protection Authority Victoria (EPA) runs the Beach Report program, which forecasts and monitors water quality for recreation at 36 beaches around Port Phillip Bay during the summer season. Water quality is determined by the levels of bacteria in the water, which can pose an increased risk of disease for people coming into contact with the water.
This summer’s Beach Report period ran from 1 December 2017 to 12 March 2018.
Fast Facts for 2017-18
- Of the total water forecasts issued over the summer, 76 per cent were Good, 13 per cent Fair and 11 per cent Poor (2016-2017 forecasts were Good 77 per cent, Fair 15 per cent and Poor 8 per cent).
- Five swim advisories and four water quality alerts were issued over the summer for Port Phillip Bay beaches.
- Forecasts were provided to over 6,500 followers on Twitter.
- Over 10,000 people subscribed to the water quality SMS alerts to receive notifications about Poor water quality forecasts.
How did our beaches perform?
Beach Report monitoring was every Tuesday at 36 beaches over the summer months. This monitoring is used to assess whether sites have met the end-of-season water quality objectives for swimming. For 2017-18, 97% (35 out of 36) of beaches around Port Philip Bay met the water quality objectives for swimming. We rely on the twice daily forecasts to advise people about the water quality for swimming.
Rye Beach did not meet the recreational water quality objective at the end of the season. This does not mean this beach was unsafe for swimming the whole season, but it did experience a higher number of days with poorer water quality, which can increase the risk of swimmers being exposed to disease-causing bacteria and other pathogens (e.g. a virus, bacterium, or other microorganisms).
Beach water quality has remained stable in recent years
Water quality has been generally suitable for swimming in recent years, especially during dry weather. The exception has been during and after heavy rain (see ‘Swim advisories and other water quality alerts issued over summer’ section for more information about these events).
What information do we gather and report about beaches?
The information we report on this website and through Twitter includes the following:
- Water quality forecasts:
- These are reported twice daily.
- Forecasts of Good, Fair or Poor are given for each beach to inform decisions on recreational use.
- They are based on weather forecasts, observations and warnings, water quality history, and weekly water sampling results.
- Weekly water quality monitoring:
- Samples are analysed for the presence of a group of bacteria called enterococci, which indicate that water may not be safe for recreational use due to faecal contamination.
- If it’s not considered safe to swim due to increased risk of exposure to bacteria, the public is notified on the website, Twitter and through a media release. Signage at the affected beach is put up by the local council during the week and on weekends forecast signs at life saving clubs show Poor forecasts.
- EPA works with bayside councils and water authorities to investigate the source of water pollution.
- Water quality samples are used to assess whether the site has met the end-of-season water quality objectives for swimming.
- Alerts about pollution incidents, fish deaths and algal blooms:
- Water quality alerts are given all year round.
- Alerts are based on reports from the community, businesses and government, EPA or other responding agency.
Pollution can be reported at any time to EPA on 1300 EPA VIC (1300 372 842).
How accurate were Beach Report water quality forecasts?
The accuracy of Beach Report forecasts was measured by comparing bacterial water quality sampling results at beaches to the corresponding morning forecasts (10am) on the same day.
- 93 per cent of forecasts provided appropriate advice about whether it was safe to swim. That is, when actual water quality was Good EPA issued either Good or Fair forecasts. When water quality was Poor EPA issued either Poor or Fair forecasts.
- 82 per cent of forecasts correctly predicted the actual water quality, so the forecast matched water sample quality of Good, Fair or Poor.
- Missed alarms were issued for ten out of 783 forecasts issued on Tuesdays over summer, or <2 per cent of total forecasts issued. Of the 38 Poor water quality sample results on Tuesdays, we issued Good forecasts for ten of them. However, these ten missed alarms related to only one or two beaches at a time; the remaining 34-35 beaches on those days were provided with appropriate advice.
- Forecasting can provide false alarms. Of the Good water quality samples over the summer, 6 per cent were issued with Poor forecasts.
For more information on how we generate forecasts and the accuracy of our forecasting go to Generating forecasts for Beach Report and Yarra Watch.
Water quality and health for swimmers
Increased risk of illness occurs when water is contaminated with human or animal faeces. Beach Report monitors enterococci at beaches, bacteria that are an indicator of faecal pollution. Faeces may carry any number of disease-causing organisms (pathogens), with gastroenteris being the most common illness experienced by swimmers.
The level of human and animal faecal sources in stormwater and other pollution can vary according to the duration and intensity of rain, and depends on land use or activities in the catchment that flows to a beach. Studies in in previous summers have found human and animal faecal contamination at Port Phillip Bay beaches or in stormwater drains:
- Research by EPA, Melbourne Water and Monash University in the 2014-15 summer found human and animal faecal sources at three beaches during and after rain and stormwater pollution. In this study, human faecal sources were detected in 73 per cent of samples from Elwood, Frankston and Rye Beaches, with the main sources being sewage from sewers and septic tanks, and greywater (e.g. waste water from baths, sinks, washing machines, and other kitchen appliances). Animal faeces were detected in 14 per cent of samples, with waterfowl (water birds) being the main source.
- In 2015-16, an investigation by Centre for Aquatic Pollution Investigation and Management (Melbourne University) and EPA found human faecal contamination in 46% of dry weather flows in stormwater drains in the Frankston CBD, entering Kananook Creek and possibly the Bay. Animal sources were found in 14% of samples, with dog and seagull faeces the most common source.
- Human faecal contamination was confirmed at seven beaches in the 2016-17 summer, in the week following a storm on 29 December 2016. Bird faecal contamination was also found at five of the beaches sampled.
- The extent of human faecal contamination at Port Phillip beaches or stormwater drains is comparable to studies in other parts of the world. For example, up to 60% of samples at a beach in a Californian (United States) study contained human faecal contamination, and up to 95% of samples in a Lisbon (Portugal) study.
High bacterial levels in stormwater run-off and river discharge can be caused by sewer and septic tank leaks, cross-connections between sewage and drainage systems, litter and animal faecal waste (for example, bird and dog droppings) entering drains and rivers. Additionally, following heavy rain events, such as early December 2017, sewage overflows from emergency relief structures increase bacterial levels in stormwater drains, rivers and the Bay.
In dry weather, potential sources of faecal contamination at beaches include:
- sewage spills
- sediment from stormwater pollution containing bacteria, that is re-suspended in water by strong onshore winds
- leaking sewer infrastructure (particularly where it is overlies the stormwater drainage system)
- leaks from toilet facilities and septic tanks
- sewage/wastewater treatment plant discharges
- cross connection between sewage and drainage systems
- bather shedding (faecal bacteria shed from the body during bathing/swimming activity)
- boat sewage discharge
- animal faeces
- decomposing seagrass/seaweed with bird faeces attached
Increased levels of enterococci can be expected as a result of these inputs, however from historical data, elevated concentrations are usually short-lived (48hrs).
What influenced water quality and forecasts this summer?
During rain events, pollutants in runoff wash down stormwater channels and out into the Bay, which increases the risk of swimming at nearby beaches.
When a rain event occurred, Beach Report informed the public by issuing a water quality forecast of Poor, advising the public to avoid swimming near stormwater outlets, rivers and creeks for 24 to 48 hours after rain had stopped. This advice is based on 16 years of Beach Report monitoring data (Table 1). Poor water quality can last for longer than 48 hours, but this is rare and more likely after a large storm. This season, extended periods of Poor forecasts were mainly issued during periods of heavy rain. These occurred around early December 2017 and late January 2018.
Table 1: Time taken for enterococci results to return to below the short-term human-health-related trigger level. Results below collate Beach Report data between 2000-2016 (over 8000 samples).
Percentage of weekly samples returning below short-term human health related trigger over time.
Swim advisories and other water quality alerts issued over summer
There were five swim advisories issued for Port Phillip Bay beaches this summer. Swim advisories are issued if there are high bacterial levels during dry weather. This is when people are more likely to use the beaches for swimming and when pollution would not be expected (as there is no rain). Swim advisories are based on the weekly sampling at 36 beaches.
When EPA issued advisories, it worked with councils to put signs up at beaches while an investigation was conducted. Investigations concluded that advisories during dry weather could have been caused by sediment from stormwater pollution containing bacteria, that was resuspended in the water by strong onshore winds.
The five swim advisories issued were:
- 22 December 2017, St Kilda Beach
- 9 February 2018, Port Melbourne Beach
- 15 February 2018, Mornington Life Saving Club
- 16 February 2018, St Kilda Beach
- 2 March 2018, St Kilda Beach
There were four water quality alerts issued for pollution that could have impacted beach water quality. There were based on reports received by EPA from the public and businesses:
- An alert was issued on 1 December 2017 due to forecast high rainfall and flash flooding. There was a high chance of sewerage, chemicals and other contaminants discharging into waterways and the Bay. All beaches were also downgraded to Poor.
- A pollution alert was issued on 11 December 2017 for the beach between Patterson River and Chelsea Longbeach Surf Lifesaving Club after reported discoloured water. The source was determined to be high flows into the Bay from Patterson River due to recent rain. Monitoring found bacterial and algal levels as not harmful to health.
- A pollution alert was issued on 5 January 2018 for Black Rock Beach after sediment was discharged from a stormwater drain into the Bay. The alert was removed when the sediment dispersed.
- An alert was issued for on 3 February 2018 for Beaumaris Beach due to sediment discharge resulting in discoloured water. The alert was removed when the sediment dispersed.
All water quality alerts were removed after the pollution, dead fish or algal bloom could no longer be detected or were no longer visible. Pollution discharges to the bay can be difficult to investigate as EPA relies on timely reports from the public and for the pollution to still be occurring when EPA officers arrive at the scene. Pollution should be reported to the EPA hotline on 1300 EPA VIC (1300 372 842).
Forecasting algal blooms in the Bay
Algae are present year-round in the Bay, but can become algal blooms in the days or weeks after heavy rains that carry an increased nutrient load into the Bay. Nutrients are a food source for some algae. Algal blooms can cause harm to people through skin irritation. Occasionally, blooms may include one or more toxin-producing species. These can cause harm through the consumption of seafood (particularly shellfish) that have been exposed to the bloom.
EPA also has the capability to provide general forecasts during high risk periods for algal blooms in the Bay. This is based on algae data from monitoring equipment on the Spirit of Tasmania II and using information on river inflows and air temperature.
Two algal bloom alerts were issued this summer for Bay beaches. An algal bloom alert was issued on 22 December 2017 for St Kilda, Brighton and Williamstown Beaches due to a red tide bloom. The bloom dispersed in the following days. A second alert was issued on 6 February 2018 for a bloom near Werribee South Beach. Sampling determined algae was not harmful and alerts were removed once the bloom was no longer visible.
Water quality signs at Port Phillip Bay beaches
Water quality forecast sign at Mordialloc Life Saving Club. Source: EPA Victoria
EPA is partnering with Life Saving Victoria to continue showing water quality forecast signs at more beaches around Port Phillip Bay.
In 2017-18, all 28 life saving clubs in Port Phillip Bay displayed water quality signage. The signs inform beachgoers of water quality forecasts and other water conditions for swimming.
EPA Beach Report will continue to work with bayside councils, Life Saving Victoria, water authorities and other parts of government to improve the delivery of Beach Report communication and to protect recreational water quality at Port Phillip Bay beaches. EPA Victoria is striving to improve communication methods to provide the most effective and readily accessible forecasts.
EPA Beach Report will continue to trial and apply new technology and techniques to provide rapid communication about bacterial levels in the water, and to better understand and tackle faecal pollution.