A Drainage problem has been found
Reported in the Drainage category by Oxfordshire County Council at 09:40, Fri 14 September 2018
Sent to Oxfordshire County Council 5 minutes later
A Drainage problem has been found by Oxfordshire County Council
State changed to: Action scheduled
Updated by Oxfordshire County Council at 09:41, Fri 14 September 2018, and a defect raised
Flooding on Moreton Rd at entry to Aston Tirrold.
I farmed the adjacent land from 1975 to 2010 and have access rights. I have followed this problem for 45 years.
This flooding has been ongoing for some 20 tears since the council upset the occupant of 'Mizpah' (opposite) who rodded the pipe/culvert out whenever it blocked. The culvert/pipe lies under the farm access track and joins a very large drainage ditch with an excellent fall. This ditch is always dry as a result.
The area of road drained by this culvert is almost exactly 0.5Ha and there is also some discharge from adjacent drives and roofs. For a peak rainfall rate of 100mm/hr this gives a flowrate of 500 m^3/hr or nearly 150L/s JUST FOR THE ROAD SURFACE.
Although this culvert has been jetted many times over the 20 years its either a very narrow pipe inadequate for the flow or (more likely) its only had a small hole blown in the impacted debris that blocks immediately there is significant flow.
It may well be that a proper cleaning of the culvert **to its full bore** will fix this problem for a very long time or alternatively a larger diameter pipe is required.
I note from <a href="http://www.standardsforhighways.co.uk/ ha/ standards/ dmrb/ vol4/ section2/ ha10704.pdf">http:/ / www.standardsforhighways.co.uk/ ha/ standards/ dmrb/ vol4/ section2/ ha10704.pdf</a> in 4.7 that
" The minimum culvert diameter should be 450mm as smaller sizes are prone to blockage."
I think it is unlikely that the culvert is of this diameter which explains its routine failure due blocking.
In order to ensure that this problem is solved rather than patched up only to rapidly fail again I think a site meeting with access to the private land so the entire drainage system can be examined, would be a very useful exercise for everyone.
Posted anonymously at 08:56, Thu 15 November 2018
Moderated by Oxfordshire County Council at 10:07, Thu 15 November 2018
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