Press release

Blue Green Algae remains present in four Lake District locations

Lake users advised to remain cautious

So far this summer, the Environment Agency has confirmed that Blue Green Algae is present in four Cumbrian locations. Windermere, Ullswater, Coniston Water and Killington Reservoir have all tested positive for the Algae (cyanobacteria), posing a risk to the health of people and animals.

With sampling taking place on a weekly and monthly basis, a number of other locations have also been tested, but so far have come back negative.

As welcome as the dry weather is for some, it is obvious that with higher temperatures and prolonged low rainfall that some areas of the natural world are suffering and the increase in Blue Green Algae across the usually damp Lake District is just one consequence of this.

Jim Ratcliffe from the Environment Agency said:

Blue Green Algae is a completely natural summertime occurrence, however it can be toxic and as such, users of these lakes must remain cautious. As well as having a negative effect on the appearance, quality and use of the water, it can also move around – you could see it one day, but it may have moved the next.

We rely on members of the public to report suspected appearances of Blue Green Algae to our Incident Hotline on 0800 80 70 60. Once a report comes in we will send our samplers to test it and if confirmed, will contact landowners such as local authorities encouraging them to display warnings to notify the public of the health risks.

We will then continue to take samples of affected lakes throughout the summer on a weekly or monthly basis.

Water bodies affected by Blue Green Algae, or Algal Blooms may appear to be green, blue-green or greenish brown and can produce musty, earthy or grassy odours. Blooms can also cause foaming on the shoreline, which can sometimes be confused with sewage pollution. During a bloom, the water becomes less clear, blocking sunlight and stopping plants in the water from growing.

Blue Green Algae naturally occurs in inland waters, estuaries and the sea. Blooms can form when their numbers become excessive. Once algal numbers are high, the bloom is likely to persist throughout the season, declining only on the onset of cooler conditions.

Some types of algae, for example blue-green algae, form blooms and scum which can result in the production of toxins. These toxin producing blooms are called Harmful Algal Blooms. These toxins can be harmful to wild animals, farm livestock and domestic pets. In humans, they have been known to cause rashes after skin contact and illnesses if swallowed. Not all algal blooms and scums are toxic, but you can’t tell just by looking at them, so it’s best to assume they are.

From widespread moorland fires on parched ground, to fish in distress due to low water levels and algal blooms – these are all indications of the prolonged dry weather affecting our environment. Hot and dry weather also brings a range of challenges at waste sites, mainly amenity issues like dust, odour and flies but also increased fire risk.

This week the Environment Agency announced its support to United Utilities’ plans for water restrictions across the North West ‘to help reduce demand for water during this period of prolonged dry weather and protect the environment as well as public water supplies.’

Cumbria’s unique geography makes it sensitive to high and low rainfall and the Environment Agency works with communities throughout the year to manage this. During dry spells it’s not unusual for some rivers and lakes in the North West to deplete quickly, during even short periods of low rainfall, and they tend to recover quickly when the rain returns.

If we have intense rainfall on dry or compacted ground it runs off rapidly making river levels rise rapidly. This can cause localised flooding so it is possible to have floods during prolonged dry periods.

For further information visit the algal blooms advice page. Advice on what to look out for, and the effects of blue-green algae, can also be found at

Published 19 July 2018