Amec has now come back with the scope of additional work it will carry out in an effort to show why its client, Aggregate Industries, does not need to leave the 1m of unquarried material above the maximum water table to protect people’s drinking water supplies; the 1m that is typically required of other operators. Yet another report will be produced and consulted upon to support AI's planning application to quarry Straitgate Farm, this time to include a full survey of all surrounding groundwater dependents including the mediaeval fishponds at Grade I Cadhay, the results of infiltration testing of overburden, and:
Description of the plan for excavating to the maximum water table level but still maintaining a 1 m unsaturated freeboard, and justification of why the use of overburden will be suitable. The results of the infiltration testing etc. will inform this section of the Summary Report. In addition, the concepts will be illustrated by annotated sketches.
When Amec says "maintaining a 1 m unsaturated freeboard", what it really means is a summer and winter working regime, entrusting AI to only quarry down to the maximum winter water table during the summer months when groundwater levels are lower, backfilling with top soil and subsoils before groundwater levels rise in the winter. Of course, restoring just 1m of soils above the maximum water table would not normally be considered adequate to protect drinking water supplies from future land use pollutants - the infiltration testing on site this month, of back-fill against in-situ material, will check drainage rates not attenuation of nitrates. Furthermore, the estimated maximum groundwater level is unlikely to be the maximum, when it has only been derived from the last couple of years' data.
It’s interesting, because not so long ago Amec was the same set of consultants that assumed that 1m of sand and gravel was to be left unquarried:
And made its conclusions based upon that:
In removing a proportion of the unsaturated zone including the soil layer there will be a reduction in the storage capacity/buffering and so recharge may move more quickly through the unsaturated zone. The extent to which this makes the groundwater hydrograph more “flashier” would be difficult to quantify with a high degree of certainty… Within the proposed development the establishment of a 1m freeboard over and above the highest known water level provides for this eventuality.
Amec was the same set of consultants that admitted uncertainty over where the maximum groundwater level actually was:
...there is uncertainty about how smooth the [seasonal groundwater elevation] transition is because there is no piezometer in the centre of the Site and there is the possibility for steps in the water table related to faulting 2.4 ...unmapped local faulting... 3.1 ...the two [maximum water table grids] therefore represent just two of the many possible interpretations of the data which themselves are based on an incomplete parameterization of the detailed groundwater dynamics of the site 4.2 Groundwater levels do not fluctuate evenly across the site... 4.2
But then Amec was also the same set of consultants that produced a "conceptual cross section across Straitgate Farm" , Fig 3.1, to illustrate the groundwater regime - the same sort of smoke-and-mirrors diagram that AI used in the seven suits meeting to hoodwink the EA and DCC; a cross sectional diagram showing the piezometers PZ01, PZ02, PZ03 and PZ11 where groundwater levels are recorded.
But look carefully, and in the new report too - when Amec says that "the concepts will be illustrated by annotated sketches", because there are NO piezometers running in a line across the middle of the proposed extraction area; the position of the piezometers don’t even match the corresponding section line that Amec has drawn on Fig 2.2, see below. When PZ01, PZ02, PZ03 and PZ11 all lie outside the area AI wants to quarry, it's no wonder Amec admits that there's "incomplete parameterization of the detailed groundwater dynamics of the site".
So is Amec really prepared to now make the case for AI to quarry right down to the maximum water table and forget its previous conclusions, forget about all the uncertainty over groundwater levels, forget about rigour and professional integrity? AI has put Amec in a difficult position. But that's what you can do if you are a multinational cement conglomerate - and the first set of conclusions don't suit.
