If you were planning to make the most of the prolonged summer in the central west by heading to Burrendong Dam this weekend, you had better make alternate plans.
Late on Friday a red alert warning was issued for blue-green algae at the popular waterway, indicating that people should not undertake recreational activities where they may be coming into direct contact with the water, such as swimming.
Domestic uses for water such as showering and washing should also be avoided, while livestock and other pets may also be under threat due to the outbreak.
The particular species of blue-green algae identified at Burrendong are potentially toxic and may cause gastroenteritis in humans if consumed, and skin and eye irritations after contact.
The often-used technique of boiling the water does not remove algal toxins, and is of no benefit.
Warning signs are positioned at key recreational areas and will remain in place while high levels of blue-green algae are present.
People are advised not to enter the water, not to drink untreated water or bathe in water drawn from the dam while the alert is in place.
Water NSW is keen to let residents know that town water supplies remain unaffected and are safe to drink.
Livestock owners are reminded to continue to check stock water supplies for blue-green algae and to remove stock from foreshores where surface scum is visible or blue-green algae are suspected.
Blue-green algae usually appear as green paint-like scums on the water, near the edges, or as greenish clumps throughout the water. It makes the water appear dirty, green or discoloured and generally has a strong musty or earthy odour.
People should not eat mussels or crayfish from Red Alert warning areas.
Any fish caught should be cleaned and washed thoroughly in uncontaminated water and any internal organs disposed of before consumption.
Blue-green algae occur naturally and can reproduce quickly in favourable conditions where there is still or slow-flowing water, abundant sunlight and sufficient levels of nutrients.
It is not possible to predict how long the algae will remain at high levels.
Regular monitoring will continue and the alert will be lifted as soon as the high levels of algae dissipate.
People who believe they may have been affected by blue-green algae are advised to seek medical advice.
Updates about blue-green algae blooms and red level warning areas can be obtained by calling 1800 999 457 or visiting www.waternsw.com.au/water-quality/algae