An extensive and damning new report has been produced which seriously undermines Aggregate Industries’ plans to quarry Straitgate Farm. An expert in hydrogeology, tasked with looking at the plan's impact on Cadhay's drinking water supplies and listed mediaeval fishponds, concludes:
My assessment of the proposed quarry is that it will cause problems to the groundwater system.
The expert is Professor Rick Brassington Eur Geol Eur Ing BSc MSc CGeol FGS CEng MICE FCIWEM, an independent consultant who has more than 50 years of professional experience in hydrogeology, and who has authored more than 30 scientific papers and two hydrogeology textbooks. More recently, Prof Brassington gave evidence at a public inquiry in relation to an application for a sand and gravel quarry on the edge of Hertford. The appeal by the applicant was dismissed – a decision endorsed by the Secretary of State last month, as we posted – based in large part on the risk to public water supplies.
In the case of Straitgate, Prof Brassington recognises that:
The groundwater resources that lie beneath the area around the proposed Straitgate Farm site are fundamental to the lives of more than 100 people in their homes and to the local businesses that they run. 6.6
The Environment Agency has a statutory duty to protect such "precious groundwater resources":
‘Groundwater zones’ #Groundwater is water held in pore spaces in rocks beneath our feet below the ‘water table’. Groundwater originates from rainfall & infiltrates down through ‘soil zone’ into the #rocks reaching the ‘saturated zone’. Eventually it discharges into #river valleys pic.twitter.com/DvvwoJ8oHZ— Geoscience EnvAgency (@GeoscienceEA) May 9, 2019
Before looking at Prof Brassington’s report in more detail, let’s remind ourselves what DCC’s Mineral Plan – "the policy framework for decisions by Devon County Council on planning applications for mineral development over the period to 2033" – says on groundwater in Policy M21:
The sustainable development of minerals should seek to conserve and enhance other natural resources, and proposals will be permitted where they would: (a) not harm the quality, availability and/or flow of surface water and groundwater and the integrity and function of the water system, both surrounding and, where relevant, within the site;
Let’s also remind ourselves how AI and consultants Amec Foster Wheeler tried to pull the wool over peoples’ eyes – including the EA – in their most recent response on hydrogeology:
The reduction in thickness of the unsaturated zone during works and post site restoration will not have any effect on groundwater quality. 2.17.7
It’s clear that Prof Brassington couldn’t disagree more. He 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.
He says the EA has not recognised that this groundwater resource is "very sensitive and fragile", and says "the EA should… strongly object to the proposal":
The EA states that its policy is to provide protection to sensitive areas where groundwater resources are of fundamental importance. It is strongly suggested here that the number of groundwater sources in the area around Straitgate Farm and Cadhay House where alternative water supplies are not easily available at an affordable cost means that the aquifer that feeds the local springs falls into this category. 5.2 ... 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 strongly suggested here that the proposal will have a large impact on the local groundwater environment that is not recognized in the AMEC reports and therefore the EA should require the application to be refused. 5.9
He says AI’s and AFW’s efforts have been "to ensure that the maximum volume of stone can be removed from the site rather than to provide adequate protection for the groundwater resources" 5.8, and calls on DCC to refuse permission:
For the reasons stated above, Devon County Council is asked to refuse planning permission for the operation of the site. The method of working that is proposed is untried anywhere else in the country and is designed to maximize the sand and gravel dug with no regard to the changes it will inevitably bring to both the quantity and the quality of the groundwater and the springs it discharges through. Both these changes will cause difficulties to the users of these private water supplies. 6.13
Prof Brassington says AI’s unorthodox scheme is "untried and untested" and would not work in practice:
this operational procedure is too difficult for typical machine operators 4.20… [and] will not work in practice when the machine operators will be left to dig with little guidance 4.24.
On the subject of AFW’s guesstimate of the maximum winter water table – the MWWT, the base of any quarry – Prof Brassington says:
...the MWWT is not a representation of the maximum water table readings for the proposed quarry site. 4.16 ...the MWWT elevations proposed are not accurate and are out by almost 3 m in places 4.24.
In contrast to AI’s and AFW’s assumption that "the recent winter months of 2012/13 and 2013/14 [are] indicative of peak levels 4.2.11", Prof Brassington points to base flows from the Salston Stream – one of the four watercourse emanating from the site, whose flows are recorded by the EA – and says:
It can be concluded that the higher base flows in 1976/77 and 2000/01 would have resulted in higher groundwater levels across the site in a similar way that higher levels have been observed in the late winter of 2017/18. 4.23
What if that MWWT surface were remodelled to accommodate those elevated maximum water table readings? Prof Brassington says that even then:
A revised MWWT would not be acceptable as the groundwater system in the area is vulnerable and any quarrying would cause problems. 5.6
On the subject of groundwater quality, Prof Brassington says:
The proposed quarrying operation will reduce the groundwater recharge and reduce the spring flows. This is likely to lead to water shortages and the hardship that this brings. 6.2
Why? Because:
the aquifer is relatively thin and any reduction in the recharge it receives caused by an increase in runoff from the overburden used to make the protective layer… will make it even thinner thereby reducing the volume of groundwater held in storage. This will reduce the flows of the springs and could easily make them incapable of providing the volume of water required for drinking purposes. 3.25
Furthermore:
The reduction in the unsaturated zone will reduce the time taken by percolating waters to reach the water table. As a result, there will be less time for the chemical and biological processes that develop the groundwater chemistry and the spring water will be more acidic and have a lower dissolved mineral content. 6.3
Not only that, but:
... the flows of both the Cadhay Wood Stream and the Cadhay Bog Stream will reduce as well as the various springs that flow into these woodlands. This will have a detrimental impact on the viability of the ecosystems that is expected to be permanent. 3.30 ... reduced flow of the Cadhay Wood stream will impact on the Cadhay mediaeval fishponds. 6.10
On the infiltration areas proposed, to protect Ottery from flooding, Prof Brassington says:
The proposed infiltration areas are sited where maximum groundwater levels have been recorded, as little as 0.43 m below ground surface, seemingly rendering them unworkable. 4.49
It’s all damning stuff, and Prof Brassington is unequivocal in calling for the application to be refused. If DCC nevertheless ignores such advice, putting the profits of a multinational before the security of drinking water supplies for local people, Prof Brassington says that extra safeguards would be needed:
If Devon County Council are minded to grant permission for these proposals, despite the evidence given in this report, they are asked to ensure that an unquarried buffer of at least 3 m is left above the maximum water table to minimise the negative impacts. It has already been demonstrated that the MWWT surface cannot be modelled accurately, neither can the MWWT be reliably adhered to during the operational phase. 6.14
AI, on the other hand – in its profit-hungry-wisdom – has proposed a 0m unquarried buffer above the maximum water table to safeguard water supplies – not "at least 3m". Furthermore:
If Devon County Council do grant permission for these proposals, they are asked to ensure that Cadhay House is included in the Section 106 properties and that this document specifically states that AI will promptly fund without any delay a replacement water supply to all those impacted by their workings. 6.15
Why is all this is so important? Water is of course essential for life, essential for people, businesses and wildlife. The fact that AI and consultants AFW – for the sake of an inconsequential and ever-decreasing amount of sand and gravel, not essential for the local or national community – are willing to play fast and loose with the security of private water supplies to three livestock farms and 100 or more people around Straitgate – plans that Prof Brassington says would "lead to water shortages and hardship" – is shameful.
What’s also shameful is that not only were AI’s legal assurances for alternative water supplies "unfit for purpose", but that AI was not prepared to include Cadhay in any Section 106 agreement covering alternative water supplies and/or compensation in the event of a failure caused by any quarrying at Straitgate Farm. According to DCC:
The view of AI remains that the information provided means that the risk is negligible and therefore does not need to be taken into account in the EA or the s.106.
Of course, if that risk were indeed negligible, it would have been painless for AI to indemnify Cadhay from any losses arising from quarrying activities. The fact that they won’t infers the company is fully aware of the risks and the potential financial exposure. It should be obvious to anyone that disruption of water supplies to Cadhay – a Grade I listed Manor House – would be catastrophic to the upkeep and maintenance of this historic treasure.
Prof Brassington’s report can be found here. It has been sent to DCC and the EA.
