Eutrophication – excessive growth of algae in waterways – is expected to increase over the next 30 years due to the impacts of climate change.
According to a report from the Environment Agency called Climate change and eutrophication risk in English rivers, an increase in eutrophication is expected until the 2050s followed by an unexplained decline towards the 2080s.
Risks from eutrophication, the algal bloom caused by excess nutrients in waterways, include alteration of water quality and restrictions in the way water can be used.
The removal of phosphorus is a priority for most wastewater utilities thanks to the requirements of the Water Framework Directive (WFD) which sets ecological standards for watercourses. These standards require wastewater treatment works to tighten their consent limits.
Eutrophication risk is predicted to increase at 26 sites across England until the 2050s followed by a reduction at half these sites by the 2080s.
The study showed flows in the rivers studied are regularly low enough to contribute to bloom algal risk but that is dependent upon conditions remaining warm and sunny, an area where the report suggests further research is required.