Brentford residents have raised concerns about sewage flowing into the local canal network with dead animals reportedly washing up.
At a meeting of the Brentford and Syon Area Forum on Monday (September 21) Paul Keane told local councillors that the issue is being made worse by the “epidemic of heat” experienced this summer. The dead aquatic animals, the exact species of which were not specified, were mainly spotted in the Brentford Lock basin, where the Grand Union Canal runs through Brentford before merging with the River Thames.
According to Mr Keane, sewage is flowing directly into areas where water sports activities are hosted, with the issue thought to be at least in part caused by misconnections, whereby plumbing from housing developments is mistakenly connected to surface water drains instead of sewers, so untreated waste ends up in waterways.
He said: “The big fly in the ointment is sewage coming into the canal. That gets worse in the summer when the water is moving slowly, and some of that is historic, but also a contemporary mis-directing of sewage into storm drains.”
He made clear that whilst he did not believe it is the fault of Hounslow Council, it is something that needs to be focused on “if we do want to develop usage of the canal, particularly for children on the water”. He added: “The water has to be hygienic, and there are times when it simply isn’t. It’s a very difficult issue, but it needs an overall strategy.”
Responding to the concerns, Councillor Katherine Dunne said: “There is some cross-borough working, particularly on that issue. There’s a River Brent catchment area group, and we know that officers in Ealing and Brent are looking closely at the issue of misconnections. But you’re right, it originates in those boroughs and then comes down into ours.”
Mr Keane went on to tell the forum that this summer dead animals were found in the canal – predominantly found with E. coli and botulism. Botulism in aquatic animals is caused by ingesting toxins which thrive in warm shallow water.
According to Mr Keane, the main area dead wildlife was found is around the Brentford Lock Basin. He argued that the second section of water within the locks around Boston Manor Park is the most stagnant.
Stagnant warm water acts as a biological incubator that rapidly accelerates the growth of E-coli whilst simultaneously creating the conditions required for botulism outbreaks. Botulism can only grow in environments with very low oxygen – stagnant warm water creates this environment.
As water temperatures rise, the physical capacity of water to hold dissolved oxygen drops dramatically. The lack of movement in the water prevents oxygen from mixing into the water from the air – coupled with E-coli animals eventually die from both diseases.
He told councillors that before hosting water sports events, the Canal and River Trust conducts water tests, and has found that the water is “generally quite clean”.
Committee Chair, Cllr Dan Bowring, thanked Mr Keane for bringing the issue to his attention, noting that the sites sit within the Brentford West ward – urging residents to contact their local ward councillors. He added: “All councillors in Brentford will be concerned about this, as would all residents.”
In August, just nine miles away in Ruislip, a resident spotted dead fish washing up on the shore of the Lido. This was determined to be caused by algal bloom, which caused a drop in oxygen levels in the water.
It is understood that hot weather exacerbated the conditions in Ruislip Lido that led to the deaths of fish with low oxygen levels.
