So, there are now two independent hydrogeology experts who have serious problems with Aggregate Industries’ scheme to quarry Straitgate Farm; two independent hydrogeology experts who have discredited AI’s hydrogeology reports and found fault with their conclusions. How many more experts will be needed before the Environment Agency sits up and takes note?
Whilst, incredulously, the EA is prepared to accept AI's highly unorthodox working scheme – despite evidence that AI's model of the water table has already failed dramatically – both Dr Helen Rutter and Professor Rick Brassington point to the proposal's serious risk to drinking water supplies to over 100 people, 3 farms and a Grade I Manor House. Prof Brassington says:
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
With the Boeing 737 Max scandal, there has been much talk recently of "regulatory capture", or:
what happens when a government agency’s relationship with the industry it oversees becomes too close for comfort; instead of acting primarily in the interests of the public, it puts the needs of businesses first.
Let’s hope that’s not the case with the EA, who works closely with the aggregate conglomerates – here being just one example.
One section of Prof Brassington’s report was devoted to how – based on the the agency's own policies – the EA should be responding to this application:
it is strongly suggested here that the EA has not recognized that the hydrogeology and groundwater resources of this area are very sensitive and fragile. 5.5 It is expected that the EA should object strongly to this proposal. 5.6
A major bone of contention is the location of the maximum winter water table. AI proposes to quarry down to this level. It clearly doesn’t know exactly where it is.
AI and its consultants Amec Foster Wheeler (now Wood) quote the MWWT to cm precision, yet in places it is clearly out by almost 3m. The EA is of the view that the MWWT can be re-guesstimated using recent elevated levels "immediately before operation of the quarry begins" – despite infiltration plans being unable to work with groundwater so close to the surface – but it has at least pushed AI/AFW to provide tolerances, errors in +/- m, for this surface: numbers first asked for in 2016, which have still not been provided, at least publicly.
AFW say the winters of 2013 and 2014 – conveniently and coincidentally when AI first started monitoring the area – can be relied upon to derive, model, guess, the maximum water table:
Monitoring over the exceptionally wet winters of 2013 and 2014 allow this surface to be defined with confidence. 6.2.2
Both Dr Rutter and Prof Brassington disagree. Prof Brassington says:
...the MWWT is not a representation of the maximum water table readings for the proposed quarry site
Prof Brassington points to the records of Salston Stream – included in AFW’s hydrogeological assessment – which indicate that groundwater levels would have been higher across the site in both 1976/77 and 2000/01.
How then were AI/AFW so sure that 2013/14 could "allow this surface to be defined with confidence"? AFW pointed to other borehole records around the area, compared historic readings with those from 2013/2014, and then employed some smoke and mirrors:
Whilst it is recognised that 2013 and 2014 are considered to be extremely wet years in terms of rainfall, the observed groundwater level data themselves do not provide sufficient context to establish whether the observed groundwater levels might be considered to be close to the historical maximum. Therefore additional historic data for both rainfall and groundwater levels have therefore been obtained from the EA and reviewed to better understand the historical fluctuations in groundwater levels. 4.2
AFW looked at the records for the Salston Stream – one of the four watercourses emanating from Straitgate. It looked at the baseflows – the stream flow sustained between precipitation events:
Daily flow data for the period 1976 to September 2016 have been examined for the nearby weir at Salston, located 2.5 km downstream of the Straitgate site. It is clear that very high baseflow occurred in the winter months of 2012/13 and 2013/14, reflecting high BSPB spring flows (and therefore high groundwater levels). The only previous periods characterised by similarly high baseflow were the winter periods of 2000/01 and 1976/77. 4.2.8
Clearly, however, the baseflows recorded in 2000/01 and 1976/77 – as Prof Brassington points out: "1976/77 being over 11 Ml/d and 2000/01 some 7.5 Ml/d compared with 6.5 Ml/d for both 2012/13 and 2013/14" – were not convenient to AI/AFW’s argument. And here's the clever bit: In the next line – when AFW pointed to borehole Bussels No 7A, for which there are long term records – AI's consultants effectively dismissed both 2000/01 and 1976/77 at one stroke:
The nearest CEH groundwater index well with similar geology is located at Bussels No.7A, constructed in the Permo-Triassic sandstone in the Exe Valley. Groundwater levels in the winter of 2012/13 and 2013/14 rose c. 0.3 m above the previous long-term maximum level recorded in 2000/01. 4.2.8
No mention of 1976/77, but how very convenient for AI. Where actually is Bussels No 7A?
Miles away. Is it representative of monitoring boreholes around Straitgate, which are 6-12m deep? No. Bussels No 7A is 91.44m deep. Dr Rutter says "I don’t consider it relevant":
this well is over 90m deep and unlikely to respond to recharge in the same way as the shallow groundwater.
At Bussels No 7A, "annual fluctuations are normally between 1 and 2 metres." Boreholes around Straitgate see annual fluctuations as much as 6 metres.
AFW also pointed to records from "four EA observation boreholes … within the Otter Valley" to substantiate its claims. However, as Dr Rutter says:
the report suggests that all of the EA monitoring wells show that 2013/14 represented the historical highest GWL. Longmead stopped recording in 2012, and West Hill Village Hall has a short record, therefore this conclusion cannot be drawn from either of these. Salston Cottages looks as if there were similar high levels around 2000/01, and other earlier years… Woodbury Common appears to be the only one that you can say definitely had higher levels in 2013/14. But again, without some comparison of groundwater level responses between this well and the site piezometers, it is not possible to say if this well is representative.
But based on Bussels No 7A, and the other dodgy assortment of borehole records, AFW then made the grand claim – a claim that dictates the total resource and total profit that can be recovered by AI from Straitgate, the raison d'être for the whole planning application – that:
These data provide supporting evidence for using the exceptionally high groundwater level conditions in the winter months of 2012/13 and 2013/14 as indicative of peak (winter) groundwater levels. 4.2.9
Amazing.
Another case of outright deception from AI’s consultants, or just a simple lack of professional nous? Either way, it won’t bring any comfort to the many people who rely on the area for their drinking water, who will no doubt ask the question: Can any of the conclusions in AI's hydrogeological and flood risk assessments – for example, when the word "unlikely" is used – be trusted?
