Users of the River Medway have been told to stay clear between Tonbridge and Yalding after dangerous algae was confirmed on the water.

The Environment Agency has alerted boat owners, dog walkers and residents after blooms of Blue Green algae formed along the 12km stretch.

The algae can cause stomach pains, vomiting, diarrhoea and skin rashes. Though the risk to people is relatively small, animals such as livestock and pets can become seriously ill.

Chairman of the River Medway Users Association, Mark Smurthwaite, has given his warning on the toxic blooms.

He said: "It's horrible stuff, you don't want to ingest it.

"Due to the nice weather we have had more people swimming in the river but it only takes a splash on the face to cause symptoms.
"Boating is perfectly ok but be careful when canoeing and paddle-boarding.

"It's best to keep well away and to not disturb it because it could break it up and that could cause it to grow more."

Dog owners are urged to keep their pets out of the water. People are advised not to touch any scum at the water’s edge.

The Environment Agency's operations manager Ian Nunn said: "We are working with Tonbridge and Malling and Maidstone Borough Council to ensure everyone who enjoys this stretch of the Medway is aware of the issue and that people are kept safe.

“It is very hard to tell if an algal bloom is toxic just by looking at it so it is safest to assume it is. People should keep themselves, children and pets away from the affected stretch of river from Tonbridge to Yalding until further notice and avoid skin contact with the water or algae."

The algal bloom was confirmed on Tuesday. Warning signs are being put up at locks and sluices along the riverbank.

Blue Green algae is a naturally occurring phenomenon. Blooms are more likely to form during warm, settled, dry weather but can also appear after heavy rain.

Mark said: "Because it grows so fast it's actually a pollutant.

"It forms a blanket on the top of the water stopping sunlight reaching the river bed and takes all oxygen suffocating the river and its wildlife.

"We don't get it very often - it has been spotted before but never like this.

"Due to no rainfall, the river is running very slowly and so it's been able to grow so quickly.

"If it flows away it could contaminate the rest of the river.

"We put it down to the hot weather making the perfect conditions for it to grow fast."

At the moment the contaminated areas sit in six sections of the River Medway, split up by the locks between Tonbidge and Yalding.

But Mark warns that - depending on the river flow speed - affected areas could reach as far as Maidstone.

It can also cause foaming which is sometimes confused as sewage pollution. There is advice about Blue Green algae here.

If you spot Blue Green algae near you, it should be reported to the free 24-hour hotline on 0800 80 70 60.