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Lake Advisory for Orlando’s Lake Rowena has been lifted

The Lake Advisory for Lake Rowena for an algae bloom has been lifted.


UPDATED Information – Lake Rowena is being closely monitored for presence of microcystins (toxins) by City of Orlando and Florida Department of Environmental Protection (FDEP) staff. On Thursday, January 21, 2021, the City of Orlando staff will be sampling Lake Rowena again for algal toxins. The city's tests will provide an update on the presence of microcystins, but the official toxin determination is obtained from FDEP’s laboratory data. We will not know results from FDEP for another 2-3 weeks. At this time, the Lake Alert remains in effect until FDEP’s results indicate that Lake Rowena is deemed safe by current state standards.

Please continue to call the Lake Alert number, 407.246.2220, for the most up-to-date information regarding your lake. During weekdays, the City's Lake Alert website, orlando.gov/lakealert will also have the latest information.


On January 7, 2021 the City took water samples in Lake Rowena to determine the presence of microcystins (toxins) resulting from an algae bloom in the lake. It was determined that potentially unsafe concentrations of toxins are present in Lake Rowena. As a precaution, we are advising everyone to refrain from swimming, recreating and irrigating in/from Lake Rowena until further notice.

For reference, cyanobacteria/blue-green algae are always present in the water, however, not all bacteria have the ability to produce toxins. Toxicity is hard to predict because a single species of algae can have toxic and non-toxic strains. This instance is believed to have occurred due to the water in the lake "flipping." During the colder months, the warm surface water begins to cool. As water cools, it will become more dense, causing it to sink. This dense water forces the water of the bottom layer to rise, turning the layers over. The bottom layer tends to be very nutrient rich, then is exposed to sunlight at the surface level and causes an algae bloom to occur.

Nothing can be done to treat algae blooms without causing massive fish kills. Due to this, the City will continue to closely monitor and test the lake weekly until the levels are deemed safe by state standards.

Please encourage your neighbors t