A guest post from Owen Biggs.

As I live in West Kensington. I am due to be deluged with the noise, pollution, dust, dirt and inconvenience should Thames Water start a £169+ million pound project to build a new sewer link. An inspection shaft located yards from my front door means more than two years of having lorries driving past my front door and at periods 24 x 7 drilling works.

I find it rather ironic that this summer when we had substantial amounts of rainfall in a relatively small period; I believe the figures were a month rain in three days, there were only two or three properties flooded in  Hammersmith and Fulham.

To fit a one way valve to protect these properties from flooding costs about £3,000 per household. In contrast the apparent lack of investment in a robust maintenance programme for Thames water has given us two cases of serious flooding in the last month. The latest reported in today’s papers being in Islington and the flooding of a number of businesses and million pound mansions. On the 26th November we had a similar incident where both residential and business properties were flooded and a bus fell into a sinkhole created by the burst water main on Islington High Street.

Time and again when challenged as to the need for the multi-million pound project that Thames water is about to embark on. Despite protests and resistance from the local council and many individual households immediately and obviously impacted by the proposed works. Thames Water refer to the flooding that hit the nation in 2007 and damaged hundreds of houses.This project, we are told is to safeguard against something like that happening again. Yet a closer look at the figures suggest that they do not support this approach.

To be clear. The flooding of 2007 was in the words on the Environment Agency Report “unprecedented’. To cite this as the driver for this new sewer design is to “over engineer” to some considerable degree. Let us review in a little more detail the figures surrounding the floods of summer 2007. Over 55,000 households nationwide were flooded that summer. This was due to an unprecedented level of rainfall in May and June of that year that had never  been experienced before, at least not since records began in 1766, more than 250 years earlier!

Of the 55,000 households flooded nationally only 1,300 of those were in Greater London. Details of the exact dispersion of these flooded properties is difficult to come by but I will persevere. Let us assume then that the area covered by Counters Creek proposal accounts for as much as 20% of those properties. Highly unlikely but it gives us a figure to work with.

The Ofwat report indicates that the cost of this proposal is unlikely to be less than £169 million and many expect this cost to rise. A simple division of costs then show that to address an issue that has happened only once in all recorded history by the Met Office and Environment Agency is to be levied on the customer at a minimum cost of a little under £646,154.00 per household affected. This is what I mean by cost benefit. Nor has it been determined that this additional sewer link would have the capacity to manage a a similar sustained downpour as that seen in the summer of 2007. Figures quoted are referenced from the Environment Agencies Review of the 2007 Floods.

Additional reference is made by Thames Water to an in-house survey that purports to show  1,700 properties in the borough having suffered from flooding in the last ten years though the assumptions made and conclusions reached on these figures are dubious at best. My house has been flooded twice in the last ten years. Once when the cold water header tank sprang a leak and once when a pipe burst. In neither instance would this very expensive project have averted or mitigated the damage done yet it is assumed that all 1,700 instances lend credence and support to the Counter Creek proposal.

Consider recent events in Islington and Lewisham, how would this have helped if such a scenario were to be played out in Hammersmith and Fulham? It would not!

I am currently trying to find additional information on this dataset from Thames Water as without a breakdown of causes, location, time frame etc. Little that is of worth can be drawn from these figures.

I earnestly hope that what I have been able to demonstrate here is that at present little hard evidence has been made available to support the Counters Creek proposal and it’s continuation unless facts based evidence is provided would be seen as no more than a raison d’etat.

Recent events suggest that Thames Water would be best advised to invest this money into reinforcing or reinvigorating a maintenance program that appears inadequate to the task of maintaining its current infrastructure in good and effective working order.