Email thread dealing with Wet Spots 7 and 7B
1 - OGAFCA to RBWM Planning - 28.07.2021
Re : 21/02208/FULL Plot 3 between The Lodge and Garden Cottage, Fifield Road
For some time we have been concerned about the drainage implications of this development and the potential threat this poses to all Residents and properties south of Stewart Close down to the Bray Wood Memorial Hall.
All the water from this area must flow eastwards along a major ditch from a chamber under the footway at the south-western corner of Plot 3.
The footings of Plot 3 appear to encroach on this ditch and potentially compromise it.
We are unable to find any online details of original submitted plans or planning conditions that deal with this subject.
Please could you provide reference information that will allow us to see what provision has been planned or stipulated to safeguard against potential disaster at this location ?
OGAFCA - Environment
2 - Project Centre to OGAFCA - 03.08.2021
The developer applied for land drainage consent in addition to the planning approval. Project Centre met with the developer on site in February to discuss the requirements, and then subsequently reviewed and approved the application.
The drainage network upstream of the discharge point into the ditch which flows through the development site is a fairly defined, small catchment. The pipe which discharges from the highway drainage (from chamber C on the Wetspot 7 map), and picks up the ditches close to the Fifield Inn and close to Stewart Close, discharges through a piped headwall into this ditch. The downstream pipe which the developers are installing has a hydraulic conductivity 420% of the full bore discharge rate of the pipe discharging from the highway drainage network. Surcharging of the network from the newly installed pipe will therefore not occur, as long as the new owner undertakes the required maintenance which is required of all riparian landowners.
The pictures of the ditch in question in your most recent newsletter confirm that the levels of water got quite high on, and around, June 18th. If surcharging of water in this ditch occurred it may be because the downstream receiving network was not able to accept the volume of flows from the development site. This may be because the hydraulic capacity of the ditch through the development site had been artificially increased so the new pipe could be laid, whereas the downstream network had not been, leading to a high degree of surcharge. The downstream network will be inspected as part of our ongoing work in Fifield.
Please do continue to notify us of development in the Oakley Green/Fifield area that you feel may have a detrimental impact on flood risk. As lead local flood authority we are statutory consultees on all major applications (more than 10 dwellings), but it seems prudent to provide formal comments on smaller development given the flood risk history of the catchment. We will also action this with RBWM planning on our end.
3 - OGAFCA to Project Centre - 03.08.2021
Thank you so much for your very detailed response. This is very much appreciated and a relief to know that local concerns around the continuing threat from water in Fifield are taken seriously.
Because of the concern of Residents in that particular area of Fifield would it be acceptable if I add the text content of this thread to the web site as an update report ? I could of course put together a general summary but I think it is preferable if the original text is available as I believe it carries more credibility.
As a reminder I would like to flag up again the additional problem associated with this particular drainage network. The Fifield Inn has been suffering for years (well, decades actually) from the inadequate capacity of the drainage heading northwards underground from the car park entrance. This local business suffers frequently and badly from the results of this and we think they should reasonably expect something to be done to improve things. It would be encouraging to know that some competent professional attention is being applied to ensuring the existing network functions as well as possible in addition to considering the possibilities of improving the onward flow or delaying the arrival of water at this point - or both.
Once again, many thanks for taking the time to investigate and respond.
OGAFCA - Environment
4 - Project Centre to OGAFCA - 19.08.2021
With regards to the Fifield Inn, my understanding (please correct me if Iím wrong) is that the car park owned by the pub floods as a result of insufficient capacity of the ditch/piped section which is also privately owned by the pub. Unless there is interaction from the highway which exacerbates the flooding in the car park I would consider this a matter for the pub to address rather than RBWM to get involved in. Volkers recently jetted this culvert line as part of their work in the area, so the condition of the piped section should not be causing any problems. However this work was undertaken as a courtesy, and responsibility for maintenance remains with the riparian owners.
From a holistic perspective improving the onward flow, may lead to an increase in flood risk further downstream which could impact properties, so I would be reluctant to encourage this. Attenuation upstream of both ends of this section of drainage network should be considered as part of the wider project looking at flood risk in Fifield, if our funding application is successful.
5 - OGAFCA to Project Centre - 24.08.2021
Many thanks for your reply.
Yes, as I understand it the problems at the pub result from a lack of capacity in the onward route under the car park entrance.
It is good to hear that the pipe has been jetted so we can now assume that any repeat is caused by lack of capacity rather than silted blockage.
I was absolutely unaware that the pub owns the underground piped section from their car park, under all the front parking areas for the cottages, and into the next section of open ditch.
Are you able to enlighten me on what the ownership-responsibility situation is as the pipe passes under the frontage of each cottage ?
I presume the pub cannot be held responsible for the entire length of this route ?
If the capacity were to be improved and this pipe excavated and replaced would the responsibility be shared between all that row of landowners ?
I completely agree with your comments about the necessity for upstream attenuation. This is something OGAFCA raised nearly a decade ago and we have been advocating it ever since as I hope was clear from our references presented at our TEAMS meeting. Streetcare claimed to be investigating possibilities but there was never any conclusion. Let's hope something can finally begin to move forward on that front.
Once again, many thanks for your attention to these issues.
OGAFCA - Environment