Wessex Water are undertaking a pioneering investigation into water quality in the popular wild swimming spot near Bath
By Alastair Salmon
Wessex Water is monitoring the variations in water quality at Warleigh Weir and is making that data available for the public whenever they choose to go swimming. It allows the public to make informed decisions on whether to use the weir based on water quality on a 30-minute basis.
Since last spring, Wessex Water has been gathering data for the project, with samples from the river regularly analysed at Wessex Water’s lab in Saltford.
Chris Tattersall is Wessex Water’s Environmental Investigations Programme Manager, and he explained that water quality, especially bacteria levels, can vary widely depending on conditions. Wet weather can consistently influence bacteria levels but treated sewage effluent and storm overflow from public sewage can also deteriorate water quality. Agricultural influences such as faecal matter from livestock and surface water runoff also affect bacteria levels.
“It’s helping us to understand how water quality changes under different flow and rainfall conditions and what the sources of bacteria might be.”
Last autumn, Wessex Water installed censors in the weir that can feed information to an AI programme that works out likely bacteria quality in a 30-minute timeframe.
But Chris emphasised that while the project can track trends in water quality, directly monitoring bacteria levels in rivers isn’t feasible in itself. “This is a problem the whole water industry faces; here, we’re measuring other parameters and other aspects of water quality and developing the relationships between those and bacterial water quality.”
This is still a significant undertaking despite limitations, especially with recreational water usage increasing over the past few years. Even more so through the pandemic, ensuring that water quality can be analysed and then fed to the public is essential.
Also significant is to consider additional risks to wild swimming, especially in Warleigh Weir, which, while very popular, still has no lifeguard system in place. Chris reiterates that the public must consider the risks presented by bacteria and cold-water shock, strong currents, and other dangers of drowning before entering the river. Wessex Water’s monitoring of Warleigh Weir will continue into next year, and you can find more information on that, including their UK first water quality app, here