On Wednesday, August 5, signs across University Parks warned that "recent dry weather" had caused an algal bloom, which it said, "may be harmful to humans and pets". These large growths of algae or bacteria in waterways can be dangerous to human health and fatal to dogs. "Please be aware that there is currently an algal bloom in the river caused by the recent dry weather conditions. While this algal bloom warning has been retracted, concerns remain about the impact of climate change and drought in Oxfordshire as well as the health of its waterways. The UK Centre for Ecology and Hydrology's 'Bloomin' Algae maps' show a "confirmed bloom" in the Farmoor Reservoir, and a "plausible" bloom at the Wolvercote Mill Stream.