Forecasts, like the weather, are based on a collection of data (i.e. is a beach more prone to poor water quality because of its proximity to a drain), the predicted weather conditions, weekly samples, pollution and naturally occurring events such as algal blooms and fish deaths.
This summer, water quality was generally forecast as good in the Bay and good to fair for the Yarra (please see graph)
Both Beach Report and YarraWatch posted nine unconfirmed alerts (where EPA was required to investigate further following a pollution report). Field investigations revealed the pollution reported in those instances had either ceased and rapidly dissipated or did not pose a risk to human and environmental health and they were removed.
In addition to these unconfirmed alerts, Beach Report and Yarra Watch posted three confirmed pollution alerts (when EPA was advised of pollution by water authorities). These alerts corresponded to a sewer spill in Damper Creek, a sewer spill in Darebin Creek at Alphington and a chemical spill in Laverton Creek at Derrimut.
The community was notified of all alerts, both confirmed and unconfirmed, by Twitter, through the media and the alert box on this website to avoid contact with water until further notice.
In these cases, EPA continues to test the water until we are comfortable that the water quality is suitable for recreational use and the forecast can return to fair or good. In most cases water quality improves around 24-48 hours after rain.
For the Yarra River, Kew and Healesville had predominantly fair forecasts this summer. A fair forecast means that recreational water quality could be affected by rainfall particularly if the site is close to a stormwater outlet or in the case with Healesville, water quality can be susceptible to agricultural/semi-rural runoff after heavy rain, while the Kew site is in a heavily urbanised area.
Eastern, Blairgowrie, Mt Martha, Portsea, Sorrento and St Leonards beaches had the highest number of ‘good’ forecasts while Rye, Safety Beach, Rosebud, Port Melbourne, Mornington, Dromana and Canadian Bay had the highest ‘ fair to poor’ water quality forecasts. In these cases a poor rating was either ahead of or following rainfall.
This season we also rolled out forecasting signage at 10 bayside beaches as part of the new partnership with Life Saving Victoria.
Large signs were displayed during patrol hours and lifesavers were provided with mobile internet access to allow them to receive regular updates to provide beachgoers.