Forum Topic

Thames Tunnel and Mogden

I've finally got round to glancing at the proposals for the Thames Tunnel (mentioned on the Forum front page and details of consultation athttp://www.thamestunnelconsultation.co.uk/            )Obviously I haven't been keeping up because I thought that it was going to be the answer to the problem of Mogden sewahge works overflowing into the Thames, carrying the surplus downstream to Beckton.The plans show it is only going to go as far west as the Acton storm tanks. So if Mogden overflows, sewage will still go into the river to kill the fish, poison the rowers and make Brentford smell.After that surprise google then found for me the minutes of the March 2009 meeting athttp://democraticservices.hounslow.gov.uk/%28S%28to3ted35c21nxr55eb24vind%29%29/mgAi.aspx?ID=44727where the Sustainable Development C'tee were discussing the Mogden expansion proposals. As I skimmed them it seemed to imply that Thames Water reckoned the larger capacity would reduce the frequency of discharges :"Mr Aylard  explained that the flow into the works was not constant and more arrived at the works after it rained, which had to be treated, stored or discharged into the river rather than allowing it to back up. The proposal would provide a new treatment stream, which would increase and improve capacity by approximately one third for better treatment of the sewage. The proposals would not bring any more sewage to Modgen and discharge into the river would go down to approximately once a year." The minutes record "Councillor Dakers asked why the Thames Tunnel could not be extended to Mogden and used for overflow. " and got the response "The Tunnel was only a long thin storage tank and it needed to be a certain size to work properly. The furthest the tunnel would go upstream was to Chiswick Ait. Heavy rainfall and sewage would go into the Tunnel and on to Beckton, where it was pumped out. The Tunnel could not be extended because the cost benefit analysis did not allow for the extra four miles to Mogden. "If Mogden is the major source of the problem and the place where the storm water from the sewers of most of North and West London ends up, it doesn't seem satisfactory to continue to let it annually poison the Thames while Thames Water spend the money on a greenwash PR campaign to fund an expensive "long thin storage tank" that won't solve the problem.Or has anyone seen the figures to convince themselve that it will all work happily ?

Tim Henderson ● 5706d3 Comments

Andrew Dakers provided this interesting informationSewage in the Thames  New figures obtained by Mike Tuffrey shows that just in August more than 6.5 million cubic metres of sewage flowed into the Thames – the volume of 1741 Olympic size swimming pools.  Since the New Year the total amount of sewage flowing into the Thames now exceeds 40 million cubic metres.http://www.gla.libdems.org.uk/news/000867/65_million_cubic_metres_of_sewage_dumped_into_thames_during_august.html

Steve Taylor ● 5703d

Looking back at the history of the plans for the tunnel, it appeared to me that nothing much was happening until the heavy rainstorm of August 3rd 2004 happened.Mogden overflowed spectacularly and provoked lots of fish kill headlines. The publicity drove acceptance of the proposals to beef up the sewage treatment works and provide the tunnel to deal with the combined sewer overflows downstream of Hammersmith. At the cost of around £1/wk added to the water bill per customer for the next ? years.But I'm  convinced that if the same August shower occurred again when it was completed, Mogden would still react the same and the same number of fish would be killed !Curiously I came across the catalogue of significant and major pollution incidents from sewage discharges into the Thames around the Mogden discharge in the Environment Agency "What's in my backyard" site - but the August 2004 incident wasn't there :http://tinyurl.com/38tchqv

Tim Henderson ● 5703d

"If Mogden is the major source of the problem and the place where the storm water from the sewers of most of North and West London ends up, it doesn't seem satisfactory to continue to let it annually poison the Thames while Thames Water spend the money on a greenwash PR campaign to fund an expensive "long thin storage tank" that won't solve the problem."Absolutely correct - unfortunately the dimwits on the SDC couldn't understand the proposals and refused to listen to our environmental scientists proposals. As far as Thames Water were concerned - its all about shareholder profits.

Steve Taylor ● 5703d