It is recommended that local government develop harmful algal bloom preparedness and response measures, including key steps that should be taken in the event of a harmful algal bloom being detected.
Incidents of algal blooms are predicted to increase with the impacts of climate change. Developing a simple response plan will ensure local governments are prepared to effectively respond to incidents that occur.
Preparedness and response actions as part of this plan should consider:
Installation of health warning signage and temporary closures
- Local governments should have a stockpile of standard health warning signs that can be erected when required. The department has a health warning sign template that can be modified to include individual agency logos and contact numbers (as appropriate). For a copy of the template email algalblooms@health.wa.gov.au
- Health warning signs should be placed in visible areas where people are likely to access the water. For example, the entry point to jetties, boat ramps and shorelines.
- Ensure barrier tape is available to visibly section off areas people commonly access the water, particularly where children or pets may enter.
- The department has a limited stockpile of health warning signs that can be made available in an emergency if extra signs are required. Email requests to algalblooms@health.wa.gov.au
Risk communication and public warnings
Local governments are well placed to advise people and their pets to avoid swimming and other water-based activities, particularly where there is noticeable discolouration or scum.
Communication should address:
- type and nature of the bloom (e.g. species or toxin levels if known, colour, scum and other characteristics, proximity to recreational areas)
- potential health risks and symptoms
- areas to avoid
- safe practices e.g. avoid swimming, fishing, collecting shellfish and other water activities
As part of risk communication messaging can be disseminated through:
- social media
- website
- newsletters
- community alerts via email, sms or other systems
- local community groups and sporting clubs who may access the water such as:
- rowing clubs
- lifesaving clubs
- schools or other companies teaching swimming lessons in recreational water bodies
- speed boat/water skiing clubs
- hire companies renting out boats, kayaks, stand up paddle boards and other water-based activities
- any other local communication channels as required
It is recommended that a response plan list the contact details of common community water user groups and other frequent user groups of recreational water bodies in their jurisdiction, so if a potential harmful algal bloom is identified these groups can be reached quickly.
Local governments can liaise with the Department of Health water team on key health messaging.
The public and community groups should be provided regular updates until it is confirmed that the water is safe.
Site inspection and sampling
Where a harmful algal bloom is detected, a local government may need to:
- conduct a site inspection and document bloom characteristics (location, size, colour, odour, presence of dead fish and other sea life)
- undertake water samples for algal/phytoplankton analysis, including having sampling bottles (obtain from DWER for response purpose) and other sampling equipment ready e.g. PPE, esky, ice-bricks, Lugols solution etc.
- undertake follow up samples in liaison with the Department of Health, until it is confirmed that the water is safe for water activities/use.
- investigate any potential pollutant sources that may be contributing to excessive nutrients in the water to determine if measures are needed to prevent future impacts. This can include:
- running drains and stormwater
- sewage outfall
- on‑site or private sewage disposal systems
- intensive agricultural activities, possibly resulting in run‑off of untreated animal effluent
- adjoining rivers and streams
- slopes affected by erosion
Coordination with government agencies
Environmental health services should coordinate their response with the: