In order to protect surrounding private water supplies, Condition 30 of Aggregate Industries’ permission to quarry Straitgate Farm stipulates:
Piezometer coverage across the site shall be, at any time, no less than the proposed one piezometer at each corner of each working sub-phase. Piezometers which are lost through quarry working shall be replaced within seven days. Continuous monitoring of all site piezometers (and interpolation between them) shall be used to ensure, during working, that the base level to which the quarry is worked is no closer to the measured groundwater level than 1 metre.
Our emphasis.
Three working phases have been proposed, with two sub-phases in each.
Even as things currently stand, there is no piezometer on the SE corner of Phase 1.
Furthermore, it is patently clear – and has been for years – that there are large areas on the eastern boundary that cannot be quarried without breaching the MWWT, given that groundwater has now been recorded just 1.19m, 0m, 1.26m and 1.59m below the surface at PZ2017/02, PZ2017/03, SG1990/021 and SG1990/012 respectively.
The eastern boundary of Phase 1 and Phase 2 will therefore need to be redrawn.
Piezometer PZ2017/03, at the NE corner of Phase 1 and SE corner of Phase 2, is obviously unable to provide any meaningful information on how far to the west of this point the maximum groundwater levels would allow sufficient depth for mineral extraction, given water levels here have reached ground level.
Clearly, therefore, there need to be further boreholes drilled at the redrawn eastern boundary of the extraction area – to fulfil Condition 30, ie. so that there are piezometers at "each corner of each working sub-phase".
At least 12 months of groundwater monitoring in these new boreholes would then be required to provide any meaningful baseline.
Without new piezometers in these locations there can be no way "to ensure, during working, that the base level to which the quarry is worked is no closer to the measured groundwater level than 1 metre."
