Algae radar forecasts the occurrence of blue-green algae

Published: 3 May 2018

The new swimming season is around the corner, the weather is getting better and the holidays are not far away. We can look forward to swimming in open water. There are numerous swimming locations in the Netherlands but the water quality is not always good enough.

For example where blue-green algae are present. Despite their name, and even though they look like algae, these organisms are actually bacteria that produce toxins that are dangerous for humans and animals.

blue-green algae floating scum layer photo Miguel Dionisio Pires

They also form floating scum layers that eventually rot if they are left undisturbed for long enough. These scums are not only unsightly, they also resultin bad smells and oxygen depletion in the water, causing fish to die. Water management authorities do everything they can to prevent these conditions, but their job is complicated by the difficulty of predicting the occurrence of the algae.

Forecasting blue-green algae

Two years ago,  Deltares started developing a computer model to predict problems caused by the blue-green algae: the Algae Radar. The model tells water management authorities when they can expect difficulties with the algae so that they can intervene in good time, and more effectively. With the information from the Algae Radar they can also warn bathers in advance about the presence of the algae. The first version is already forecasting problems with the algae quite accurately. We are working in collaboration with the water management authorities to make further improvements.

Contribute to improving the Algae Radar

You can help improve the Algae Radar by taking pictures of the water at the recreational beaches in the t Twiske nature area, and at de Lijte near the Paterswoldsemeer lake. We can use the photos to check whether the forecasts generated by the Algae Radar are accurate. Send the photos of the water to, together with the date, time and location (‘t Twiske or de Lijte).