John,Thanks for the response - but it doesn't address the point I was trying to make. They seem to be referring to the events after the burst. I was musing about the control of the pressure in the main and whether there have been recent changes to the way it is controlled which might have contributed to the failure(s).Ruth Cadbury reported in her post "Thames Water and the High Street/London Road" (22/09/10 00:11:00 ) :"3 From now on TW will monitor for leaks and manage the pressure in the pipe so it does not build up as it did before the burst. It’s now on the risk register. The implication being that it’s likely that we’ll have the hassle of its replacement before long . . ."which raised the question with me as to how the pressure in the pipe was managed before the burst.It appears that in recent years there have been developments in making the system clever to minimise the pressure in the distribution system (and thus reduce leakage) while still providing "adequate" service . Those who complain of dribbling showers and burnt out shower heaters may dispute how "adequate" it is.http://www.hyderconsulting.com/EN/Careers/Pages/more.aspx?pageID=198&pageType=Articlescame up with"Pressure management, a combination of pump control, break-pressure tanks, network redesign, and pressure control valves, has proved to be extremely effective in reducing losses. Its advantage over detection and repair is that pressure management (if made permanent) produces a permanent effect, whereas leaks found and repaired will continue to recur.Pressure control usually requires pressure zones to be set up. The use of supply zones with differing pressures is very well established, but it is often cost-effective to subdivide these into small sub-zones and control pressures in each of these too. This approach is also well established in some countries: Brazil, Cyprus and the UK provide three examples. If these zones are set up for pressure management, they can be metered and become DMAs to make detection more efficient with minimal extra expenditure.The extra benefit of pressure management is that low and stable pressures reduce the number of bursts in the distribution network. There is still much debate about whether this effect is sustained in the long term, but there is ample evidence that the effect lasts many years. The Netherlands’ experience, with low and stable pressures, and low burst rates, seems to support the idea that low burst rates really are sustained."It appears that companies like i2O have been working with Thames Waterhttp://www.i2owater.com/#/02What does control the pressure in our water mains ? Does the possibility of the algorithm doing something to hammer the pipes at 6 am in the morning exist ?Thanks for the link to the full report. It would be interesting to hear the response from Syon Park about their refusal to use the flood plain for emergency discharge of the flood water. The balance between some disruption to the fishing lake and the flooding of neighbouring homes seems an easy one to call - but then it may be hard to make decisions in the heat of the emergency.
Tim Henderson ● 5624d