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Beach Report 2016–17 Summer Highlights Report

Brighton Beach

Brighton 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 2016 to 13 March 2017.  

Why did Poor water quality forecasts increase this summer?

Poor water quality forecasts are issued if there has been recent or forecast rain. There were more Poor forecasts issued this summer than in 2015-16; six per cent of all forecasts were Poor in 2015-16 compared to eight per cent in 2016-17, this equates to over 200 more Poor forecasts for 2016-17. This increase was due to more rain over the summer.

Where Poor forecasts are issued during times of warm weather, EPA defines these as high-risk swim days as more people are likely to want to swim. This summer, EPA adopted a risk-based communication approach to actively increase communication on these days to ensure that more Victorians were aware of the risks of swimming in poor water quality.

Poor forecasts on high risk days were issued during and after heavy rain experienced in late December 2016, late January 2017, early and late February 2017.

How did our beaches perform?

Beaches met end of season objectives

Beach Report monitoring was every Tuesday at 36 beaches over the summer months. The monitoring is used to assess whether sites have met the end-of-season water quality objectives for swimming. For 2016-17, 97% (35 out of 36) of beaches around Port Philip Bay met the water quality objectives for swimming. We note that as most of the heavy rain fell around weekends this summer, sampling on Tuesdays will not have captured other days when stormwater pollution was impacting some beaches. We rely on the twice daily forecasts to advise people about the water quality for swimming.

Mordialloc 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). Mordialloc Beach’s location close to the mouth of the Mordialloc Creek meant that it was impacted by stormwater runoff, which carries pollution. The Mordialloc Creek catchment received more rain in late December 2016, January and February 2017 this year than other areas around the Bay. Bacterial water quality was most affected on days when wind was pushing the Creek’s high flows towards the beach. Bacterial water quality at Mordialloc Beach was also impacted by dry weather pollution with a higher than expected bacterial result occurring in late February. EPA could not determine the cause of this event (see ‘Water quality and health for swimmers’ section for information on potential dry weather pollution sources).

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 as seen this summer (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 in 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).

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 late December 2016, late January, early and late February 2017.

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).

 

24 hrs

48 hrs

72 hrs

96 hrs

Percentage of weekly samples returning below short-term human health related trigger over time.

82%

15%

2.5%

 0.5%

 

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 all the advisories during dry weather were caused either by:

  • stormwater drains still flowing, in some cases up to a week after heavy rain.
  • sediment from stormwater pollution containing bacteria, that was resuspended in the water by strong onshore winds.

The five swim advisories issued were:

  • 14 December 2016, Rye Beach
  • 6 January 2017, Port Melbourne Beach
  • 1 February 2017, Beaumaris, Mordialloc and Safety Beach
  • 15 February 2017, Werribee South Beach
  • 22 February 2017, Carrum Beach

There were seven 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 29 December 2016 for discharges from several South East Water emergency relief structures in Murrumbeena, Bentleigh, Brighton East, Carnegie, Caulfield North and Brighton. These discharges could have entered nearby stormwater drains, waterways and bay beaches. Discharges from emergency relief structures can occur during large rainfall events, with heavy rain straining sewerage systems by increasing flows in sewer pipes beyond the capacity of the sewer. If this occurs, the excess flow (a mix of stormwater and sewage) is discharged directly into the stormwater system through emergency relief structures.
  • A pollution alert was issued on 6 January 2017 for Frankston Beaches after South East Water reported a sewer spill near the mouth of Kananook Creek. The sewer spill was stopped and the cause repaired by South East Water.
  • A pollution alert was issued for Mount Martha Beach on 16 January 2017 after South East Water reported a sewer spill to Balcombe Estuary.  The sewer spill was stopped and the cause repaired by South East Water.
  • A suspected algal bloom was reported at Eastern Beach, Geelong on the 5 February 2017 (based on a photo from the reporter). However, there was a large downpour of rain the following day that dispersed the potential bloom before any samples could be taken.
  • A pollution alert was issued for Carrum and Bonbeach Beaches on 12 February 2017 due to a small fuel spill into stormwater drains from a truck crash. The spill could not be contained and any fuel that entered the Bay was left to disperse with tides and wind.
  • A pollution alert was issued for Shire Hall and nearby Mills Beach on 22 February 2017 after South East Water reported a sewer spill to a drain that has an outlet at Shire Beach. The sewer spill was stopped and cause repaired by South East Water.
  • A pollution alert was issued on 1 March 2017 for Hampton and Brighton Beaches due to discharge from a stormwater drain with a strong sewage odour. The source of the discharge could not be located.

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).

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. Human faecal contamination was confirmed at seven beaches this summer, in the week following a storm on 29 December 2016. Bird faecal contamination was also found at five of the beaches sampled. Studies in in previous summers have also 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.

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 late December 2016, 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 (fecal 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).

How accurate were Beach Report water quality forecasts?

The accuracy of Beach Report forecasts was measured by comparing morning forecasts (10am) to weekly bacterial water quality sampling results at beaches. Note that forecasts are produced twice daily, and water sampling occurs once a week on a Tuesday. Hence the accuracy test compares the Tuesday sample to the corresponding forecast on the same day. Because of this, the accuracy assessment below cannot fully represent the accuracy of all forecasts over the summer period, however it gives a good indication of forecast accuracy.

Table 2: Results of overall forecast accuracy for 2016-17.

 

Overall accuracy

 

 Metric

 What does it mean?

What will be our next action? 

Appropriate advice

98%

This is the most common measure of forecast accuracy used by other forecast services worldwide. 98 per cent of forecasts provided appropriate advice about whether it’s safe to swim. In other words 490 out of the 499 forecasts issued on Tuesdays this summer provided appropriate advice.

For example, 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.

Fair forecast ratings advise the beach user that water quality may not be suitable, to check for signs of pollution before swimming. This rating is therefore appropriate for either Good or Poor water quality, as caution is advised.

Continue to monitor accuracy to ensure we provide appropriate advice.

Forecast accuracy

78%

78 per cent of forecasts correctly predicted the actual water quality. In other words 388 out of the 499 forecasts issued on Tuesdays this summer were correct.

This means that 78 per cent of forecasts accurately predicted the actual water quality i.e. Good forecasts for Good water quality, Fair for Fair water quality days, and Poor forecasts for Poor water quality. 

Improve our forecast model to increase our accuracy.

Table 3: Results of missed and false alarms in forecasting 2016-17.

Missed and false alarms 

 Metric 

 What does it mean?

What will be our next action?

Missed alarms on poor water quality days

<2%

Good forecasts were issued for eight Poor water quality sample results on Tuesdays over summer. This was out of 499 samples in total, or <2% of total forecasts issued.

Of the 19 Poor water quality samples on Tuesdays over the summer, 42 per cent of samples (eight samples) were issued with Good forecasts. The other 58 per cent of actual Poor days were issued a Fair rating, which may still an appropriate rating to protect health as it advises caution.

On the days we issued these missed alarms it was for one or two beaches in the bay, the remaining 34-35 beaches on those days were provided with appropriate advice.

This is the type of alarm we aim to reduce the most as it may result in people being exposed to Poor water quality and increased risk of illness.

Tuesday sampling this summer often occurred several days after heavy rain. Missed alarms were due to the difficulties of forecasting several days after heavy rain events when bacterial water quality can be highly variable due to:

  • continuing stormwater runoff
  • sediment from stormwater pollution containing bacteria, that is resuspended in water by strong onshore winds

To confirm our accuracy during heavy rain we sampled bacterial water quality during rain on a Friday and following weekend in late January (20th-23rd). On the Friday and weekend we issued no Good forecasts on days of actual Poor water quality.

Improve our forecast model to ensure we reduce these types of alarms. This may include development of site-specific models and inclusion of more environmental variables we use to predict water quality.

False alarms on good water quality days

<1% 

Out of the 499 forecasts we issued on Tuesdays over summer, only one Poor forecast was issued for a site with Good water quality. These types of  alarms may have economic and social impacts if issued often.

Continue to monitor accuracy to ensure we don’t issue too many of these types of alarms.

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.

EPA issued a media release advising the public of possible algal blooms in the Bay following a storm on 29 December 2016. The storm increased Yarra River flows and nutrients in the Bay, and was followed by hot weather, both of which are good conditions for algae growth. Within a week after the media release, an algal bloom was detected and reported to the public. Recreational shellfish collectors were advised not to eat shellfish taken from Hobsons Bay after two marine algal blooms were detected in the area.

Water quality signs at Port Phillip Bay beaches

Water quality forecast sign at Mordialloc Life Saving Club

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 2016-17, 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.

Further improvements to the program this summer

EPA trialed an SMS service this season to alert subscribers about Poor water quality conditions in their local beach area.

The free SMS notification service was for Port Phillip Bay beaches only, and was divided into three areas: Melbourne, Mornington and Geelong. The public could subscribe to one or multiple areas to receive relevant Poor forecasts. By the end of summer there were over 8,000 subscribers.

The majority of feedback from subscribers was that the service was good or very good (Figure 1). Importantly, the SMSs of “Poor” forecasts were influential in people’s decision to visit beaches or swim, with the decisions of 96% of respondents influenced by the SMSs.

Graph showing SMS trial results

Figure 1: Rating of forecast SMS service by subscribers.

Beach Report ‘Fast Facts’

  • Of the total water forecasts issued over the summer, 77 per cent were Good, 15 per cent Fair and 8 per cent Poor (2015-2016 forecasts were Good 75 per cent, Fair 19 per cent and Poor 6 per cent).
  • Five swim advisories and seven water quality alerts were issued over the summer for Port Phillip Bay beaches.
  • Forecasts were provided to over 6,500 followers on Twitter.
  • Over 8,000 people subscribed to the water quality SMS alerts to receive notifications about Poor water quality forecasts.

Future directions

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.

For more information on how we generate forecasts and the accuracy of our forecasting go to Generating forecasts for Beach Report and Yarra Watch.

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