As previously reported, the drainage scheme installed by Adderbury Parish Council (APC) in the Milton Road field is NOT the scheme approved by Cherwell District Council (CDC).
Drainage engineers from CDC have confirmed that the scheme “does not meet the capacity required” and that “the current basin is not sufficient to eliminate the risk of flooding during peak rainfall periods by account of its size”.
We believe this sub-standard drainage scheme has increased the risk of flooding in West Adderbury, in particular to Tanners Lane, Roundclose Road and Horn Hill Road, for the reasons reported here.
With a period of heavy rainfall forecast, West Adderbury Residents’ Association (WARA) has written formally to Adderbury Parish Council chair, Mrs Diane Bratt, to ask why an unauthorised drainage scheme has been installed and what the Parish Council proposes to do to rectify the situation they have created.
A copy of WARA’s letter is reproduced here in full:
Dear Mrs Bratt,
It has been brought to our attention that the drainage to the sports pitches that have been constructed on Land North Of Milton Road, Adderbury under planning consent 18/00220/F, has not been constructed as required by condition no.3 of the planning permission.
In summary condition no3 requires that the outfall drainage system includes an infiltration basin that has a minimum capacity of 100.8 m3 and a minimum infiltration area of 252 m2. We are reliably informed that the infiltration basin that has actually been instructed and implemented has a capacity of just 8.0 m3 and an infiltration area of just 12 m2.
We understand that condition no3 of the planning permission was introduced by Cherwell District Council following consultation with Drainage Engineers at Oxfordshire County Council. As a result of the flood risk assessment that was completed, Adderbury Parish Council, as the developer, had to commission qualified Drainage Engineers (Forge Engineering Design Solutions) to design a drainage scheme that had adequate attenuation capacity and infiltration area to ensure that there was no increased risk of flooding to surrounding land and properties.
Given the foregoing it is clear that there is a significantly increased risk of flooding since the requirements of condition no.3 have not been met.
For your reference we have attached three photographs of the outfall detail that has actually been constructed by DW Clark and two of the consented drawings detailing the design that should have been constructed and implemented in order to discharge condition no. 3 of the planning permission.
It is clear from the attachments that the required infiltration basin simply has not been constructed such that the intended attenuation that should have been implemented does not exist.
The problem is further exacerbated by DW Clark installing a piped connection (which is not part of the consented drainage scheme) straight in to the ditch in the adjacent field which in turn runs straight to the low lying areas of Horn Hill Road which, as you may know, was the area that was flooded in 2016 following a period of excessive rainfall.
Some of our members have been asking us, as a recognised association who represents them, what we can do to support them and ensure that the drainage associated with the construction of the pitches is implemented in accordance with the planning permission. Some of these members, who are also represented by Adderbury Parish council, live and own properties in low lying areas of the village which are at the greatest risk of flooding.
We and Adderbury Parish Council do have an obligation to communicate with our membership (APC Parishioners) and inform them what Adderbury Parish Council are doing to ensure that their properties are not at risk of flooding as a result of the development that is under construction on Land North of Milton Road, Adderbury. The fact currently is that their properties are at an increased risk of flooding until condition 3 of the planning consent has been fully discharged.
To this end could you please advise us, with timescales, when the corrected drainage scheme will be in place.
We will let you know when and if Mrs Bratt responds to the concerns raised by West Adderbury residents.