It would appear that Aggregate Industries has given up 1 metre of resource in its plans to quarry Straitgate Farm – according to emails sent by the company to persuade Devon County Council's Flood Risk Management Team in its capacity as Lead Local Flood Authority to withdraw its objection.
Last month we posted DCC’s Flood Risk Team withdraws objection – WITHOUT sight of ‘a plan indicating how exceedance flows will be safely managed’, WITHOUT knowing whether a drainage scheme is even ‘feasible’.
Following an FOI request, and the release of a number of redacted emails, we can now see the reasons behind the LLFA's volte-face.
On 19 July 2021, Aggregate Industries told the LLFA:
The objection you have received shows a fundamental misunderstanding of our scheme, one of the reasons why we are monitoring the MWWT is to inform the depth of extraction so that a minimum of 1m unsaturated zone is maintained over the MWWT.
On 28 July, the LLFA confirmed their understanding:
My query is that if the MWWT keeps getting higher (closer to the ground) will there be enough depth (the report says 1.45 m) to accommodate the required volume for infiltration? Bearing in mind no excavation within 1 m of the MWWT and the fact that in some places the BSPB is as thin as 3 m (although I’m not sure where these places are).
On 18 August, Aggregate Industries told the LLFA:
Regarding depth of void excavation for runoff storage above unworked material to protect MWWT:… Effectively, the eastern downslope edge of the extraction void for phases 1 and 2 will be shifted upslope, on account of the MWWT +1m criteria limiting the ability to extract from the downslope-most edge of these phases.”
One hour later, the LLFA wrote:
I am happy with the response. Essentially they are shifting the void upslope to account for the MWWT and 1 m stand off to ensure there is sufficient depth/capacity for the runoff which is reassuring.
The void created by mineral extraction acts as the infiltration basin so there is not a single cross section as this will change as extraction progresses...
On 7 September, the LLFA withdrew its objection.
Of course, "a minimum of 1m unsaturated zone... maintained over the MWWT" is brilliant news; we have been campaigning for material to be left unquarried above the maximum water table for years.
Given that the Updated Resource Assessment claims:
The MWWT will ultimately form the base of the workable deposit, and any variation will impact the potential resource.
we have suggested that Devon County Council ask for the resource to be recalculated taking the new "MWWT +1m criteria" into account.
Or is all this just another big misunderstanding?
Has Aggregate Industries misunderstood its own scheme again?
Has Aggregate Industries – either intentionally or unintentionally – misled the LLFA officer?
