In 2013, Aggregate Industries’ consultants provided a hydrogeological report to support Straitgate Farm's inclusion in the new Devon Minerals Plan in answer to the Environment Agency’s concerns:
The number of private water supplies suggests to me that this would be a difficult site to take forward. Similarly, if this area is shown to be a significant part of the catchment for the water features near Cadhay, its deliverability as a viable site would seem unlikely.
We posted about the report at the time. The report relied heavily on an earlier report: "S J Parkhouse (1990) Report on the Reserves of Pebble Beds at Straitgate Farm, near Rockbeare, Ref No: GR10/90":
A comprehensive review of the geology across the site was undertaken in 1990. This included the installation of 24 boreholes on an approximate 200m grid across the site, to depths of between 5m and 27m below ground level (bgl), to confirm the local geological characteristics and groundwater levels. 2.2
Back in 2013, AI was claiming it had 3.1 million tonnes of saleable material at Straitgate. Now it’s clear there’s less than 1 million tonnes available, and – according to Professor Brassington – even that can't be quarried without disrupting water supplies for more than 100 people:
any proposals to quarry at Straitgate Farm will impact on the fragile groundwater system and cause the flows of springs to decrease and the quality of the water also to deteriorate. 5.7
In his report, Prof Brassington referred to data from the 1990 report, specifically the groundwater level in one of the boreholes. Groundwater levels are important because AI has proposed to quarry down to the 'maximum winter water table'; readings from this borehole puts groundwater 2.8m above the base of any quarry – in the middle of summer.
The EA has proposed to review the modelled MWWT before any quarrying starts – to take into account recorded groundwater levels that have recently exceeded it – but has already chosen to ignore data from 1990, much to Prof Brassington’s concern. In response to his report, the EA said:
We note the groundwater level reading from 1990. However, because this is just one spot reading it is difficult to judge its significance.
In other words, as we’ve already posted, the EA has chosen to ignore data directly from the site, in favour of an assortment of other boreholes miles away from the site.
It was, however, not one spot reading in isolation in 1990, it was part of "a comprehensive review of the geology across the site… to confirm the local geological characteristics and groundwater levels", as described above. The survey was undertaken by an experienced geologist – who had sufficient confidence to record the groundwater level in this location to the nearest cm. The data was relied upon by AI’s consultants SLR in 2013 to sell – to both DCC and the EA – Straitgate Farm’s inclusion in the new Devon Minerals Plan:
The assessment confirms that the site is hydrologically sensitive... [but] has shown that the site can be worked. 3.4
However, the EA was misled. The report by AI’s consultants said:
Previous groundwater monitoring data (undertaken in 1990) indicated that groundwater flows in an easterly direction from 149mAOD in the west to c.136mAOD in the east to the west of the fault. 2.2.1
What that statement forgot to mention – for reasons best known to AI or consultants SLR – was that one of the boreholes in 1990, SG1990/021, "in the east to the west of the fault", did not record water at "c.136m" but at 138.81 mAOD – 2.81m higher than the above statement suggests, and just 1.26m below the ground surface.
Take a look too at the cross sections in that report, particularly Section A-A' with various markers showing "RECORDED GROUNDWATER LEVEL (JUNE 1990)." This section runs from west to east across the site, but conveniently avoids borehole SG1990/021. In fact, notice that next to the fault, the 1990 groundwater level has been replaced with the level recorded from another borehole drilled south of SG1990/021 in 2012. Plainly the 1990 figure – and the extrapolated "APPROXIMATE GROUNDWATER LEVELS (JUNE 1990)" from it, indicated by the blue dashed lines – was far too inconvenient for AI’s consultants to include.
Would the EA have formed a different view on the merits of including Straitgate in the Minerals Plan, if it had been pointed out that groundwater in some locations was just a few feet below the ground surface? We shall never know. It wasn’t the first time that AI’s consultants had been economical with the truth, and it won’t be the last.
More worrying is why the EA – the guardian of our precious groundwater resources – chooses to ignore that data now, without contrary evidence. As Prof Brassington says:
If this [1990] value is to be ignored, then, by the same reasoning, all the groundwater data in the table can be regarded as "spot readings" and dismissed in the same way. If this is the way that the data are to be used to review the MWWT, then there can be no confidence in the results and no confidence in the EA either.
