Each week we test the water quality of our dams to ensure they meet the standards set in our Recreational Water Quality Management Plan. This takes into account direct contact with the water without water treatment. This process includes testing for the presence of algal and bacterial organisms and the toxins produced when these organisms die off.
When the water quality drops below the required standards, we close the dam for affected activities.
Warning and action trigger levels
Required standards consider primary, secondary and aesthetic water content (see definitions below) for toxins such as:
Microbial trigger levels (CFU/100mL):
- Warning to dam users for primary contact - Enterococci result ≥ 200*
- Warning to dam users for secondary contact - Enterococci result ≥ 1000
- Action to close recreational activity for primary contact - Enterococci result ≥ 500.
Cyanobacteria trigger levels to close recreational activity:
- Threshold to initiate toxin testing - Total Cyanobacterial Species and Biovolume (mm3/L-1) ≥1
- Primary contact:
- Microcystin (leucine containing) (LR) mass toxicity equivalents ≥8 μg/L
- Saxitoxin (carbamate saxitoxin group) (STX) toxicity equivalents ≥30 μg/L
- Cylindrospermopsin ≥15 μg/L
- Nodularin ≥13 μg/L
- Anatoxin-a ≥10 μg/L
- Secondary contact:
- Microcystin (leucine containing) (LR) mass toxicity equivalents ≥20 μg/L
- Saxitoxin (carbamate saxitoxin group) (STX) toxicity equivalents ≥75 μg/L
- Cylindrospermopsin ≥25 μg/L
- Nodularin ≥30 μg/L
- Anatoxin-a ≥25 μg/L.
Primary and secondary contact definitions
Three key terms are used in our management of recreational use of our dams*:
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Whole‑body contact (primary contact) — activity in which the whole body or the face and trunk are frequently immersed or the face is frequently wet by spray, and where it is likely that some water will be swallowed or inhaled, or come into contact with ears, nasal passages, mucous membranes or cuts in the skin (e.g.: stand-up paddleboarding, sailboarding, jet skiing).
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Incidental contact (secondary contact) — activity in which only the limbs are regularly wet and in which greater contact (including swallowing water) is unusual (e.g.: boating, fishing).
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No contact (aesthetic uses) — activity in which there is normally no contact with water (e.g. angling from shore), or where water is incidental to the activity (such as sunbathing on a beach).