No definitive explanation is yet to emerge for the deaths of around 900 fish – mainly small roach – in the waters around King’s Dyke, Stanground. A detailed response provided by Anglian Water to CambsNews offers a reminder that “Peterborough saw a month’s worth of rain fall in three days over last weekend which resulted in our storm overflow operating within its permit, to protect homes and businesses from flooding”.
Anglian Water says that during this time their pumps at the pumping station tripped because of the storm.
“This resulted in additional volume being discharged, still in line with our permits,” said a spokesperson for Anglian Water
“The pumps were reset by our operational teams.
“Although these spills were permitted, we know this is still unacceptable. However, this does not necessarily mean our asset activity alone resulted in the impact on the watercourse.”
Anglian Water says along this stretch of river, there are eight additional outfalls not owned by them that would have been discharging surface water and pollutants as a result of the rainfall.
These outfalls typically take water from nearby roads, ditches, drains, land, and industrial sites.
“With the Environment Agency, we have continued to monitor these other surface water outfalls between our pumping station and the site of the fish kill,” said the spokesperson.
The company said they had observed evidence of an oil slick near to one outfall, and high levels of ammonia at a second outfall.
“We continue to monitor these outfalls to support the Environment Agency with its investigation and establish all potential sources of the fish kill,” said the spokesperson.
“Because of the amount of rain which fell in a short space of time, any spill from our pumping station would have been heavily diluted and is definitely not raw sewage.
“Our initial investigations backed this up with a significant reduction in ammonia levels (one of the factors that can result in a fish kill) within 100m of the overflow point, and dissolved oxygen levels were healthy.”
The company said it had also observed that the river flows in the King’s Dyke are very low, particularly as the lock gates at Stanground are typically closed.
“Even though the evidence suggests multiple possible sources for this distressing event, our teams have worked tirelessly throughout the week alongside the Environment Agency to provide specialist aeration equipment that is helping the river recover,” said the spokesperson.
“We are also sharing all our findings with the Environment Agency to support its investigation.”
Anglian Water says it is the Environment Agency responsible for the investigation.
“We (Anglian Water) will always respond to support the natural environment in an event like this, and, in fact, investigate 6,000-8,000 pollutions every year alongside the Environment Agency, which are not caused by our assets,” said the spokesperson.
“We remain active on site in case of further rain forecasts and have extra resources on standby.”
The spokesperson added: “We, like everyone, are saddened that fish have died in Kings Dyke, Stanground.
“We will always respond to support the natural environment in an event like this, regardless of whether we believe our assets are the cause.
“We are taking it very seriously, which is why we are working alongside the Environment Agency and other agencies to investigate what has happened.
“We’ve been very open that our storm overflow operated as permitted during such heavy rainfall. However, this does not necessarily mean our asset activity resulted in the impact on the watercourse.
“We remain active on site in case of further rain forecasts and have extra resources on standby.”
The BBC has reported an Environment Agency official who said the dead fish found floating in the water died as a result of elevated levels of ammonia and low levels of oxygen.
However, the BBC also reports residents claims’ of a sewage spill but as reported above this has been denied by Anglian Water.
