YORKSHIRE Water has been fined £865,000 after illegally discharging chlorinated water into a Barnsley watercourse - resulting in more than 430 fish being found dead in one day.

The company appeared at Sheffield Magistrates’ Court on July 30 for sentencing after previously pleading guilty in February to one charge of polluting Ingbirchworth Dike near Barnsley.

Approximately one million litres per day of chlorinated water was discharged - which even at low levels is toxic to fish and other aquatic life.

Yorkshire Water was fined £865,000, ordered to pay costs of £34,979.79 and a victim surcharge of £170.

Ingbirchworth Water Treatment Works provides 90,000 people in Barnsley and South Yorkshire with drinking water every day and is fed by Ingbirchworth and Royd Moor reservoirs.

Water from the reservoirs passes through the works for treatment.

It includes an underground ‘clean water wash tank’, containing chlorine.

On November 1, 2017 an alarm was received in the Yorkshire Water control room that indicated the inlet valve on the tank had failed.

The valve was then manually opened to allow the tank to fill and maintain the water supply.

But due to a series of failures by the water company, maintenance operatives were unaware that the capacity alarm was set above the overflow pipe level.

This led to intermittent-but-regular discharges for 27 days.

On November 26 Barnsley Trout Club reported dead fish at Scout Dike reservoir.

Officers attended and counted 434 dead fish in a 1.5km stretch of water between the treatment works and the reservoir.

At this stage the discharge had been ongoing for almost four weeks and in passing sentence District Judge Tim Spruce agreed with the Environment Agency’s assertion that the fish death total is likely to have been substantially higher.

The Environment Agency alerted Yorkshire Water about the incident and the inlet valve of the clean water wash tank was returned to automatic operation.

Since the incident Yorkshire Water has made a number of improvements to the tank.

It has amended the alarm trigger so that it is activated before the overflow point is reached, and the inlet valve has been replaced.

But the firm still received a hefty fine at court last week.

Jacqui Tootill, water industry regulation manager for the Environment Agency, said: “This pollution was not caused by an unforeseen event or extreme weather.

“The systems were simply not robust enough and this wouldn’t have happened if proper checks had taken place.

“We expect full compliance from water companies and are committed to taking robust enforcement action where we see serious breaches.

“We’re pleased Yorkshire Water has now been dealt with by the courts following our investigation.”

Trevor Mayne, from Barnsley Green Party - who had already started a campaign to highlight problems with Yorkshire Water’s sewage discharges in the borough - was horrified to find out that a water supply works has also been found to be at fault.

He said: "This offence is disgraceful and completely avoidable.

“It confirms the Green Party's stance that the water industry should be renationalised to prevent the private water companies making money for their shareholders on the back of unacceptable performance.

“I hope water ratepayers are not funding this fine and that it's coming out of Yorkshire Water's profits.

“There are further questions for the Environment Agency as to why it toook them eight years to prosecute."