Wednesday, 12 May 2021

As things stand, the EA’s drainage condition couldn't be satisfied

How surface water would be dealt with in any proposal to quarry Straitgate has fundamental implications for flooding, groundwater recharge for springs and water supplies, stream flows and airport safeguarding. 

Even Aggregate Industries recognises pre-emptive planning is key to flood defence:
The Great British weather has only become more erratic in recent years, with torrential storms and heavy rain frequently causing widespread flooding and misery – and the reality, unfortunately, is that it is likely to get worse. 
The issue at Straitgate is so sensitive that the Environment Agency has already said that a number of conditions "must be secured on any planning permission", including: 
8. The working and restoration infiltration design shall ensure that drainage mimics the pre-excavation drainage. This shall be achieved following the principles described in the July 2017 Hydrogeology/Drainage Regulation 22 responses report.
But as we’ve already pointed out – here, herehere and here – Aggregate Industries’ infiltration plans could not work as described, post-extraction drainage could not mimic pre-excavation drainage. 

This issue stretches back a long way. It’s not as if Aggregate Industries hasn’t been warned. 

The development should be designed so that drainage from the site mimics, as closely as possible, the natural hydrograph in perpetuity – this will ensure that the hydrographs of springs and water courses in the area are not adversely impacted. 
We object to the planning application, as submitted, because the applicant has not supplied adequate information to demonstrate that the risks posed to groundwater can be satisfactorily managed. We advise that this further information should be requested under Regulation 22 of the Environmental Impact Assessment regulations. 
On infiltration areas, in particular: 
8. The working and restoration infiltration design should be described in detail. How will it ensure that drainage will mimic the pre-excavation drainage? 
A Regulation 22 request was duly made by Devon County Council. A meeting was held between personnel from the Environment Agency, Aggregate Industries and its consultants. Minutes were produced. On the subject of infiltration areas: 
MW [from the Environment Agency] said that the final restoration profile should mimic the current one so as to ensure recharge is not inadvertently moved from one sub-catchment to another thereby ensuring the headwater flows remained similar.
Aggregate Industries produced a response, "the July 2017 Hydrogeology/Drainage Regulation 22 responses report." Don’t worry, they fibbed: 
2.9.4 The majority (i.e. 2/3) of the planned extraction area will be at either post-restoration or pre-extraction stage, with natural runoff patterns following the slope gradient, and infiltration to the relevant sub-catchment. 2.9.8 The restoration has therefore been designed to ensure the site is restored to baseline conditions (i.e. ‘mimic’ them), with some betterment provided where possible. 
It was fiction. The final restoration profile could not mimic the current profile; there would not be "natural runoff patterns following the slope gradient" given that the base of any quarry, the revised MWWT – the blue contours – does not mimic the existing topography – the brown contours – as shown below:



And the 2/3 claim? Could just 1/3 of the site be worked at any one time? Of course not.

It is proposed to quarry Straitgate in three phases. When it comes to Phase 3, the Flood Risk Assessment says: 
3.2 Phase 3 area... Soils will be placed onto the Phase 1 area to restore this area to final the landform... Overburden will be placed within Phase 2 area, with the exception of the eastern infiltration area which is to be left open. 
In other words, as phase 3 is started, phases 1 and 2 have not yet been restored. And this is still what’s proposed, according to the newly delivered Soils Management document. i.e. 

For phase 1: 
This stage is illustrated by Drawing SF / 5-1 Rev B. The soils that are stripped from this initial phase may remain in store for a period of approximately 10 years… 
For phase 2: 
Some of the soils from Phase 2 may need to go into storage and extend the original Phase 1 bunds in the east of the site. The soils that are put into storage from this second phase may remain in store for a period of approximately 8 years… 
For phase 3:
All of the soil resources from Phase 3 will then be direct placed into the previously worked out void, as shown in Drawing SF / 5-3 Rev B. 
Again, all phases being worked at the same time – not 2/3 "at either post-restoration or pre-extraction stage". In fact, by the end of phase 2, 2/3 of the site would be excavated, and would stay this way until the end of phase 3. It was a simple thing, but Aggregate Industries still couldn’t come clean.

Monday, 10 May 2021

AI’s surface water plans rely on 3rd party culvert – and revised MWWT contours show more water would be directed towards it

Don’t laugh, but Aggregate Industries' plan for Straitgate Farm – the one it’s been working on for the last decade – is reliant on someone else's small, easily-blocked, 300mm culvert.


A large portion of surface water run-off from any quarry at Straitgate Farm would be discharged to the Cadhay Bog watercourse, via the above third party culvert that runs underneath a neighbouring field.

This issue has been around some time. In 2013, Aggregate Industries' consultants concluded:
There is extensive evidence of natural flooding across the eastern extent of Straitgate Farm. The capacities of roadside ditches and streams have not been adequate to deal with recent levels of rainfall in the area. 
In 2015, for Aggregate Industries' previous application, the Environment Agency recognised in this Devon County Council Regulation 22 document that the existing culvert would need to be improved "to reduce the risk of flooding, which has been seen to have a significantly adverse impact on surrounding settlements." A meeting was held
It was agreed by DCC and the EA that the previous comments regarding de‐culverting off‐site watercourses which had been made on biodiversity grounds would not be pursued as there was a possibility that this could increase downstream flooding. 
In any case, Aggregate Industries claimed the issue wasn't anything to do with them, because they wouldn't increase the amount of surface water running off the site: 
3.12 Improvements to the existing drainage should focus on increasing roadside ditch capacity and ensuring that culvert inlets and outlets are suitably maintained to avoid blockages from vegetation or siltation. 3.13 There is a need for work on the existing drainage beneath Birdcage Lane to improve conveyance and prevent episodes of flooding along the road, this should however be the statutory responsibility of the local highways department if it can be demonstrated by AI that watercourse peak flows are not increased by extraction activities at Straitgate Farm.
And no increase in surface water run-off is what Aggregate Industries is still attempting to claim:
2.13.7 Two discharge points are proposed: One serving the ancillary area and upper portion of the access road north of the Cadhay Bog Stream which will discharge directly to the watercourse at ‘Point A’ on Figure 2.6 below; and The remaining section of the access road south of the Cadhay Bog Stream will discharge to the roadside ditch in the far south-east of the site, which drains northwards to join the Cadhay Bog stream, as shown on Figure 2.6 as ‘Point B’. 2.13.8 This arrangement ensures that the runoff from these developed areas (ancillary area/access road) is managed within the Cadhay Bog sub-catchment, and the final rate and volume of flow discharged to the Cadhay Bog stream replicates the natural rate and volume. 
But that's just wishful thinking. In the real world, with extreme weather events becoming more unpredictable, and with a quarry upslope removing the majority of the unsaturated layer, who knows what would happen? What allowance for improving this culvert has been made in this application? None. And it doesn’t matter how many discharge points there are, both Point A and Point B would feed into the one 300mm culvert: 


Given that it was recognised this culvert struggled to take the existing run-off from the site, it was surprising that the introduction of a quarry in its upslope catchment, together with access road, 50mx50m loading/stocking/lorry parking area, wheel wash, weighbridge, tip off bay, and lagoon (variously described as 1,286m2 to less than 600m2, or 20mx20m) had not prompted a little more thought.

But with the recent submission of revised maximum winter water table contours – the proposed base of extraction – matters have taken a new twist. 

We have already posted that the revised base of extraction does not mimic existing ground elevation contours to maintain pre-extraction run-off characteristics. 

Overlaying the revised MWWT contours over the Extraction and Ancillary Development plan shows that the base of extraction would direct more surface water to the Cadhay Bog water course than existing ground levels. More surface water would flow towards the loading area, down the swale adjoining the access road, into the lagoon, and towards the ditch on Birdcage Lane.  And all of that would then need to pass through the one 300mm culvert.

What could possibly go wrong?

The Flood Risk Assessment has made no allowance for increased run-off from the revised extraction contours. The swale capacity makes no allowance for this. The lagoon capacity makes no allowance for this. The ditch capacity along Birdcage Lane makes no allowance for this. The 300mm culvert makes no allowance for this. Clearly, it's another major failing.

And how much water can already flow down the Cadhay Bog watercourse on a bad day?

Friday, 7 May 2021

AI buries ‘PZ05 adjustment’


Aggregate Industries' unorthodox scheme to work Straitgate relies on groundwater levels falling by at least 1m during the summer months to allow extraction down to the maximum winter water table – the MWWT. Professor Brassington says "the EA should object strongly to this proposal": 
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. 
Aggregate Industries' Supporting Statement claims: 
2.4.7 The resource declared assumes a working base that coincides with, and never drops below the Maximum Winter Water Table (MWWT)... Moreover, the working method ensures that the floor of the excavation will always have at least 1.0m of unsaturated gravels beneath.
However, in July 2017, we raised the issue that the Seasonal working scheme for Straitgate can't work as AI describes. We pointed to PZ05 where it showed that groundwater levels do not fall by 1m over the year. PZ05 shows seasonal movements of only 0.2m. It would therefore be impossible to quarry down to the MWWT in these areas and "always have at least 1.0m of unsaturated gravels beneath". 

In August 2017, Aggregate Industries held a meeting with the Environment Agency. The issue was discussed. The Agency said: 
If, at PZ05, the MWWT grid and actual maximum levels are the same then the summer water level cannot be 1m below the MWWT grid because groundwater levels here only vary by 0.2m. 
Aggregate Industries pushed back: 
The level at PZ05 and, hence, the ‘MWWT grid’ in its vicinity recognises this and the summer working base is ruled in this instance by the need to maintain the 1m unsaturated buffer between the MWWT and the summer water level. 
But the MWWT in the vicinity of PZ05 recognised no such thing. By October 2017, Aggregate Industries finally conceded that the MWWT contours would need to be changed
The base of the quarry working during summer months will be the MWWT with slight adjustments in the vicinity of PZ05 in order that the summer working base remains standing 1 m above the summer water level around this piezometer 
A revised MWWT was duly produced "... with small adjustments around PZ05 to retain 1m of BSPB above the summer water level." And the adjustments were indeed small, unreliably small, and given the absence of nearby piezometers, complete guesswork. 

A revised MWWT has now been submitted. It would be the base of any quarry. The Environment Agency proposes the conditions:
No working shall be undertaken below the ‘Maximum Winter Water Table (MWWT) grid’ .
...the base level to which the quarry is worked is no closer to the contemporaneous measured groundwater level than 1m.
So, why has the adjustment to the MWWT around PZ05 been removed? Did Aggregate Industries hope no one would notice? 

Thursday, 6 May 2021

AI’s greenwash document assumes no gravel at Hillhead, not 25%, not 5%, not any!

Oh dear. Aggregate Industries and Devon County Council must have been hoping for great things from the report "Greenhouse Gas Assessment of the Proposed Quarry at Straitgate Farm" by Dr Daniel Lash from The Centre for Energy and the Environment at the University of Exeter.

But it really is a pile of worthless drivel. 

In October 2020, we posted ‘Ask Exeter University to help with your CO2 problem’ – suggested DCC to AI, and indeed Aggregate Industries did just that. A report was produced. It should have been titled "How to Greenwash the Proposed Quarry at Straitgate Farm". It concludes: 
The calculations show that the proposal for extraction at Straitgate Farm with onward processing at Hillhead Quarry will result in 11% lower GHG emissions than meeting the demand for sand and gravel in proposed markets from existing quarries.
It’s a fantastical illusion, because Hillhead is 23 miles away from Straitgate. 

You might have expected more from a company loudly proclaiming it is "committed to tackling climate change", from a parent company apparently "making climate action part of everything we do."  

But greenwash is what we've got, with some whitewash thrown in too.

Whitewash? Aggregate Industries had previously told Devon County Council that:
Processing at Hillhead may be feasible, but would generate a massively greater quantity of CO2 emissions from the additional mileage required to be travelled. 8.48
Now, of course, that the company is wanting to process at Hillhead, it's a different story.

Dr Lash's report has glaring omissions and errors too. Although no credentials are provided, Dr Lash is an academic, who has advised the Devon Climate Emergency Response Group, and should know better. An academic would normally cross-check their facts, make sure they’re robust, take a look, ask around, try Google at least, not just take the word of a profit-hungry aggregates business. 

Dr Lash has not checked his facts. The giveaway is on the front page of the report: 
Any information provided by third parties and referred to herein has not been checked or verified by the Centre for Energy and the Environment, unless otherwise expressly stated in the document. 
So, not rigorous at all then. 

And it shows. Dr Lash has assessed the "Do Nothing" scenario, i.e:
The GHG emissions that would arise without the proposed quarry at Straitgate Farm, namely that the demand for sand and aggregate at the target markets would need to be met from other quarries
These calculations assume that in the absence of a quarry at Straitgate, Hillhead would NOT produce any gravel. None at all. Zero. Nada. Not for asphalt plants. Not for the Exeter/M5 market. Not now. Not in the future. Not from the 8 million tonne sand and gravel resource at neighbouring Penslade, a Preferred Area in the Devon Minerals Plan. It’s a revelation. It makes you wonder what this is doing at Hillhead:

Hillhead Quarry is an important source of sand and gravel. The site produces high quality sand and gravel and coarse aggregates for the general construction industry, concrete aggregates, building sand, asphalt and coated materials for road-making.
Devon County Council also assumes there is gravel at Hillhead at the Houndaller site: 
2.5.4 Information provided by Aggregate Industries UK Ltd [SLR (2015)] in support of their planning application for Straitgate Farm near Ottery St Mary indicates a ratio of 54% gravel to 46% sand at that site, while their reserves at Houndaller near Uffculme have a ratio of 25% gravel to 75% sand.
Photos in the Council's monitoring reports for Hillhead – above and below – give the game away too, as do the piles of unprocessed pebbles previously photographed at the site.


Aggregate Industries' very own Supporting Statement for the application to import Straitgate material into Hillhead also admits: 
2.2.1. Sand and gravel extraction has taken place on the site for some time. The 1890/91 OS map marks an ‘old gravel pit’ to the north of the site... 
3.2.3. ...the sand and gravel deposit indigenous to Hillhead Quarry is red in colour and is sand rich, containing circa 20% gravel. 
And the area next to Hillhead at Penslade? The Devon Minerals Plan tells us that:
9.3.5 In the event that Straitgate Farm proved to be incapable of being delivered, then the other site, West of Penslade Cross, would have adequate resources to enable sand and gravel supply to be maintained for the Plan period. 
In other words, in the past, the present, and the future, there's not zero gravel at Hillhead. This table from Devon County Council's Local Aggregates Assessment gives more detail:
What size is the existing reserve at Hillhead? In 2019, Aggregate Industries helpfully confirmed
The company's reserves schedule for Houndaller was subsequently revised to 2.9 million tonnes as at 1st January 2019.
So – bearing in mind Hillhead is 23 miles away from Straitgate – what fanciful figures has Aggregate Industries been able to come up with? Dr Lash has calculated that to quarry Straitgate Farm and haul material to Hillhead for processing for onward supply to markets would result in a total of 3.96 million miles. But to not quarry Straitgate, to forget all the gravel at Hillhead, and to source much of the gravel from Cornwall would result in 4.38 million miles. It’s brilliant, but complete and utter nonsense. 

If we instead remember that Houndaller next door to Hillhead has 25% gravel, then not quarrying Straitgate would save 1.3 million miles. If we remember the other 8 million tonnes of sand and gravel allocated in the Minerals Plan at Penslade next door to Hillhead, then not quarrying Straitgate would save 2.1 million miles. We’ve calculated three other scenarios too. All five scenarios result in less mileage than the smoke and mirrors from Aggregate Industries. Calculations can be found here.

But forgetting the gravel at Hillhead is just one of many problems with this report. Claiming "17,200m2 of restored orchard" at Straitgate would be planted "at a density of 2,250 trees/Ha" leading to annual sequestration of "9.3 tCO2e" is another problem. Because if 3,870 trees were ever planted in this small orchard there would be no orchard, particularly when Aggregate Industries has previously claimed "cuttings will be taken from 10 trees". 

Can Aggregate Industries not offer up a single report without something being seriously amiss?

Wednesday, 5 May 2021

Can changing your name fix your reputation?

Perhaps LafargeHolcim – parent company of Aggregate Industries – thinks it can. Shareholders have voted in favour of changing the group’s name to Holcim.

Monday, 3 May 2021

What’s the point of fancy drawings if they don’t work?

A raft of plans have been provided for the latest consultation on Aggregate Industries' proposal to quarry Straitgate Farm. These plans are supposed to demonstrate to Devon County Council that the proposal is workable. After all, if it can't be demonstrated on paper, what chance is there when the diggers arrive?

The problem is that these plans give no indication of how all the various elements – north-south bunding to stop major flooding events, gradient parallel bunds to maintain catchment flows, infiltration areas to maintain groundwater recharge, livestock tracks to maintain farming operations, hedge standoffs to allow for protection and maintenance of hedges, for example – could all co-exist together.

Has anybody checked to see that they could? It doesn’t look like it. 

Take the bunding that’s supposed to stop flooding. Aggregate Industries claims
2.18.6 ...the bund should be designed to manage exceedance flows in excess of the design event. 
But overlaying SF/5-1C with Fig A2.1, what do we find? That the area set aside for bunding is taken up by a causeway to the loading area.

Take the Farm Management Plan, supplied at the Council’s request. Aggregate Industries claims
Positions of new 3.5metre wide gateways, or potentially new gateways, that are currently anticipated to enable cattle to move between the farmyard/milking parlour and the remaining land on the holding are also shown. Proposed surfaced access tracks between 3-3.5metres wide providing this linkage are also indicated on the plan. 
But clearly the provider of that plan had not checked the other drawings, because by overlaying this plan over other working drawings, here and here, what do we find? That the area set aside for 3.5m wide farm tracks is taken up with advance planting and piles of overburden or top soil. That there are livestock tracks along the sheer face of a quarry and a new gate to nowhere. And that three fields that would need to be farmed have no indicated means of access, so even more hedgerow would need to be removed.

Is there a shortfall of material to restore Straitgate to BMV land and prop up the A30?

In the application to quarry Straitgate Farm, Aggregate Industries’ Supporting Statement claims:
3.3.5 The total overburden volume is estimated at 510,000m3.
4.9.3 All topsoil and the two subsoil (upper and lower) units will be stripped and stored separately to enable later reuse as part of final restoration. Backfilling of the floor with a minimum of 1.65m of overburden with 300mm of topsoil, over 250mm of loamy subsoil which will provide 2.2m in total.
However, the statement also claims:
3.8.2 The restoration landform allows for accommodation of the 720,000m3 of restoration materials by means of the creation of gently graded slopes down to the restored base of the quarry. The base of the extraction area will be restored by placement of at least 2 metres combined thickness of topsoil, subsoil and overburden over the quarry floor to replicate current ground conditions. For areas of the site that are to be developed as species rich grassland, then topsoil will not be used in the restoration soil profile and the subsoil would be placed more thinly on the overburden to create the less fertile growing conditions required for establishing this type of plant community. 
The new resource statement, subject of the recent consultation, puts the overburden at 600,000m3. 

But given that the "restoration landform allows for accommodation of the 720,000m3 of restoration materials" is there a shortfall of material to restore Straitgate, a shortfall of 120,000m3, some 228,000 tonnes, some 8000 truck loads? 

It’s worth asking. Not only because Aggregate Industries is miraculously claiming "no loss of best and most versatile land" – which means handling, storing, restoring exactly the same profile of soils and subsoils that were removed – but also because a large but unquantified amount of overburden would be needed to buttress the A30.

Buttressing of extraction slopes shall be undertaken in line with the submitted plans with an agreed slope profile as shown on drawing SF HWYS/1
So the question is, if all the soils and overburden removed are to go back to restore BMV agricultural land, where is the material to buttress the A30 coming from? 

It’s an important question. Aggregate Industries has suffered quarry face slippages at a sand and gravel quarry before. The MOD was involved. Aggregate Industries ended up proposing a 20m standoff and a 1 in 3 slope. Whereas, at Straitgate, the company has proposed a mere 10m standoff for the A30 and a slope of as much as 1 in 0.5, before buttressing to 1 in 6 to 1 in 8 at some later date. 

In its previous application to quarry Straitgate, Aggregate Industries pointed to the geological properties of the Chester Pebble Beds to back its claim that there would be no land stability problems: 
2.6 ...the mineral at Straitgate comprises the Chester Pebble Beds (formerly the Budleigh Salterton Pebble Beds) underlain by the Aylesbere Mudstone (silts and clays) both of Triassic Age. 2.10 Aggregate Industries has a number of operations which extract this deposit and with this evidence the assumed properties for the Chester Pebble Beds are: • cohesion (c) 25kPa • internal friction angle (φ) 35º • unit weight 20kNm³... etc 2.15 ...[with] a 10m standoff to the site boundary there is no probability of the excavation affecting the A30 carriageway. Additionally the planned buttressing adds further to the stability of the faces. 
Why does no such detail back up the current application? Is the company still sure there is "no probability of the excavation affecting the A30"? We don't know. The company doesn't say.

Perhaps the same sort of conclusion was put forward before Berry Hill Quarry in Mansfield was permitted, a now worked-out quarry and subject of a recent landslide, that is:

Aggregate Industries to pay $1.45 million to settle asphalt emissions claim

Devon County Council recently granted Aggregate Industries permission to build a 27m high asphalt plant at Hillhead on an elevated position overlooking the Culm Valley. The decision went against the advice of the Council’s Landscape Officer who advised that the application was "contrary to relevant landscape policies [providing] grounds for refusal". 

Concerns about the impact of air quality and noxious odours on nearby residents and school children were dismissed, being left to the Environment Agency to deal with
Control over emissions and odours would be addressed through an Environmental Permit that would be required from the Environment Agency. 
 

Meanwhile, on the other side of the pond, Aggregate Industries has just agreed to pay $1.45 million to settle environmental violations in connection with this asphalt plant in Massachusetts.

According to the Office of Attorney General Maura Healey: 
"This company recklessly ignored the requirements of our environmental protection laws and the health and wellbeing of its neighbors when it continued to illegally manufacture asphalt and emit odors that deeply disrupted the surrounding community. My office will continue to work with our state partners to hold accountable those who endanger our communities and the environment for their own benefit."
According to the AG’s complaint, the odors were detectable up to at least three miles from the plant. The complaint also alleges that Aggregate told the Massachusetts Department of Environmental Protection (MassDEP) that it had stopped producing the crumb rubber asphalt during MassDEP’s initial investigation, but actually continued producing the crumb rubber asphalt for months. 
Parent company LafargeHolcim has been settling environmental violations too:
 
Federal and state officials on Thursday said they reached a settlement regarding alleged water quality violations at the LaFarge Holcim cement plant in which leachate was reportedly flowing into the Hudson River. Holcim agreed to pay an $850,000 civil penalty and to comply with the rules set forth in its discharge permit going forward, said Antoinette Bacon, acting U.S Attorney for the Northern District of New York. 
Oh the difference – between the reality and the greenwash:
 

Friday, 30 April 2021

AI’s restoration plan for Straitgate doesn't make sense either

Does any part of Aggregate Industries' planning application to quarry Straitgate Farm make sense? Even the restoration plan has problems.

5.3.3 The excavation is designed to include areas of infiltration that will be sized to capture all runoff from the workings and infiltration areas will be incorporated into the final restoration design. This will be designed to enhance groundwater recharge and will increase infiltration and spring flows by the amount of overland flow that would otherwise have occurred. 
In 2013, the Environment Agency delineated a Source Protection Zone in an effort to protect Cadhay's water supplies. The above plan overlays the SPZ and maximum water table contours – the base of any quarry – over the restoration plan. 

In 2017, in its Regulation 22 request, the Council requested information on the infiltration areas: 
3.6 The MPA has insufficient information about the management of the infiltration/ephemeral pond area to determine whether it will contribute to the appropriate management of surface and groundwater flows; stream recharging; airport safeguarding and long term agricultural restoration.
Two proposed ephemeral water bodies in the low-lying infiltration areas are shown as part of the Straitgate Farm restoration scheme on Drawing SF/6 (Rev.A). The proposed restoration scheme ensures that post-extraction the site will be returned to a similar baseline condition. The proposed enhanced infiltration areas for the Birdcage and Cadhay Wood sub-catchments are not SuDS and as they are infiltration areas they will not be permanent waterbodies. They are simply a feature incorporated into the restored landscape to assist in providing some betterment over the baseline conditions. These will be formed to enhance the capture of ‘overland flow’ and to locally increase the proportion of rainfall that passes to groundwater. 
But if the restored landform is to mimic current drainage, why on earth is one of these enhanced infiltration areas – areas designed to "to locally increase the proportion of rainfall that passes to groundwater" – located outside of the area that feeds Cadhay’s spring, drawing water away from a crucial water source for a Grade I listed house?

Thursday, 29 April 2021

Depth of available resource at Straitgate is in places ZERO

Within the extraction boundary proposed by Aggregate Industries in its plans to quarry Straitgate Farm there are places where there is zero recoverable sand and gravel; in other places less than 1m.

How is it sustainable to remove, handle, store, put back, more than 2m of topsoil and overburden, best and most versatile agricultural land, to extract less than 1m of sand and gravel? The answer is – it's not.

The plan below overlays the revised maximum water table contours – the base of any quarry – over the ground elevation contours. The difference between the contours is the amount of material above the maximum water table, including soil and overburden. If we assume the soil and overburden is on average 2.28m thick, as stated in the Parkhouse Report 1990, we can arrive at the available resource. 

We find that within the extraction boundary there are clearly areas with little or no available resource.
And it may be worse than that. The new resource statement puts the overburden at 600,000m3. Across 22.6ha, an area of 226,000m2, that works out as a soil and overburden thickness of 2.65m.

This all ties in with what they knew in 1967. We’ve posted about it before. Namely, in one particular area there is no material worth recovering.
In June 2018, the Environment Agency confirmed to us in an email:
The large circle cut out of the quarry area in the 1967 plan is in the area where groundwater levels are close to the ground surface. Therefore, working in part of this area may not be possible in any case.
In August 2018, Devon County Council acknowledged in an email to Aggregate Industries:
... from talking to the EA that there are areas within the proposed working that may not be workable due to the groundwater levels. Whilst we wouldn’t require new plans overall as it’s within the red line area, we would definitely require it to be clearly shown within the working area drawings and also factored into the resource assessment so that the impact on the planning balance can be assessed. 
So, where, clearly shown, is this area on the new working drawings? Nowhere to be seen. The reason? Aggregate Industries pushed back – in this now superseded document – claiming "the extraction area, as shown on the Wood E&IS plan, remains unchanged": 
The change... results in no area being "excluded for reasons of groundwater protection" but merely a localised effect on the depth of working in a localised (eastern) part of the site. 
Good try, but wrong. From the overlaid contours above it's as clear as day that this localised area has no recoverable resource. So why is it still within the extraction boundary?

Monday, 26 April 2021

Infiltration areas to stop flooding couldn't be 3m deep – without breaching MWWT

Another major failing.

Aggregate Industries' plans to quarry Straitgate Farm propose infiltration areas along the eastern boundary to control flooding, maintain groundwater recharge for springs and water supplies, and maintain stream flows – all without becoming permanent bodies of water and an airport safeguarding hazard.

We’ve already shown that these areas can’t work as described. Surface water would not infiltrate equally along the length of the eastern boundary given the gradient of the proposed extraction base. 

But with groundwater recorded so close to the surface there are other problems too. To retain surface water run-off, these features are proposed to be 3m deep
2.18.3 Quarrying operations will be excavating down to a range of between 3m along the eastern boundary and up to 9m at the western most extremity including the overburden.
In addition, bunds along the eastern boundary would be formed: 
2.18.3 The north-south bunds shown on Figure A2.1/A2.2/A2.3 are not intended to retain water, their main purpose being visual/noise screening. 
It is claimed the bunds would only act to retain surface water during intense rainfall, including:
2.18.4 In the event of an extreme rainfall event filling up void capacity, such that depths exceeded the excavation depth and backed up against the bund. Given a maximum of 1.45m of depth is expected during the design (1 in 100 year + climate change allowance) rainfall event, and the maximum void depth is 3-9m, a significant exceedance event would be required.
However, given the elevated groundwater levels recorded along the eastern boundary, and the newly-submitted maximum winter water table contours – the base of any extraction – it is clear that it would be impossible to dig 3m deep along this boundary without breaching this new MWWT.

The diagram above overlays three plans: the phase 2 infiltration area, the surface contours and the MWWT contours. The numbers indicate the depth from the surface to the MWWT elevation at points where contours from the latter two plans intersect. Clearly, along at least half the length, a depth of 3m is not available for excavation. 

The phase 1 infiltration area would have similar problems too. 

And what's the impact on flooding? The elevated groundwater levels recorded at three locations along the eastern boundary – PZ2017/02, PZ2017/03 and SG1990/21 – may have informed a new base of extraction, but they have not informed the Flood Risk Assessment which was written in 2016.

Without assessment of this new information, who knows what the flooding implications might be? Obviously not Devon County Council, the Environment Agency, or any councillors unlucky enough to determine this mishmash of chaos.  

The issue of how surface water is to be managed has always been recognised as critical if any quarrying were to be permitted at Straitgate Farm. Clearly Aggregate Industries' planning application is still in no fit state to be determined.

AI’s ‘conservative’ model of the MWWT has been EXCEEDED YET AGAIN

Aggregate Industries may have made its "final submission of additional information" for its planning application to quarry Straitgate Farm, but it's clear that one of the most important pieces of information is still not known with any certainty.

We're referring to the maximum winter water table, the MWWT, the base elevation of any quarry, critical in determining how deep to dig, critical in determining the amount of material available, critical in determining the impacts on water supplies and stream flows. 

We have warned for years that the maximum water table could not be accurately predicted. So too have two independent hydrogeology experts. Professor Brassington warned:
...the computer model derived MWWT surface is unlikely to provide an accurate representation of the real maximum groundwater levels 
What proof do we have? Simple. The MWWT keeps being exceeded. 

In 2018, Aggregate Industries put a stop to public scrutiny of groundwater data for the Straitgate site – after groundwater levels embarrassingly exceeded the company’s guesstimate of the maximum winter water table, the MWWT, in four locations by up to 1.6m. The MWWT is intended to be the base of any quarry. It’s important to get it right, if no buffer or margin of error is to be left to protect surrounding water supplies. It had apparently been "defined with confidence", but the company still won’t come clean on its accuracy. It was shown to be wrong by a staggering 2.8m in one location.
Aggregate Industries' guesstimate of the maximum water table at Straitgate Farm – which consultants had claimed "builds in a conservatism" – has been found wanting ever since it was produced. 

No realistic margin of error – in terms of +/- metres – has ever been provided for this prediction. All consultants eventually did – having avoided the question for years – was consider the difference between one inaccurate model and another inaccurate model, pretended it was a "reflection of the ‘tolerance’", and claimed: 
a negative tolerance represents conservatism and contingency which is incorporated in the selection of the MWWT 
It sounds like bullshit, and it is. For obvious reasons, consultants did not address the inherent inaccuracies of the interpolation method itself, of estimating groundwater levels across 55 sloping acres with just a handful of numbers.

So for all that confidence, conservatism and contingency, what do we now find? Just as we thought likely last year, when we said: 
Aggregate Industries' realistic assessment will no doubt have been breached YET AGAIN. Earlier this year, PZ10 reached 102.4 mAOD – 70cm higher than in 2018. It’s virtually certain that a number of the newer piezometers – PZ2017/02 and PZ2017/03 in particular – will have recorded new maximums. 
And hey presto, water levels did indeed exceed Aggregate Industries' guesstimate AGAIN. The maximum water level in PZ2017/02, which exceeded the MWWT back in 2018, went nearly 50cm higher in 2020. The groundwater level in this location has now exceeded the company's original guess by a whopping 1.75m. Water levels in PZ06 – installed back in 2013 – also reached a new maximum, as did three other piezometers. So much for the promise from Aggregate Industries' consultants – and backed up by the Environment Agency – that 2014 groundwater levels "are likely to reflect the highest groundwater levels that may occur at Straitgate." 

How could consultants get it so wrong? Was it by erring not on the side of caution, but on the side of its profit-hungry client?

Consultants Wood have had another go and have re-guesstimated the MWWT contours. Who knows whether they're right this time? Certainly not Aggregate Industries, Devon County Council or the Environment Agency. In 2017, Dr Rutter warned
The steep hydraulic gradient combined with limited monitoring, in my opinion, is likely to result in errors in the actual depth to maximum groundwater across the site. 
As we finished by saying last year: 
The MWWT is never going to be an accurate prediction of the maximum water table. There needs to be a margin of safety, a freeboard, an unquarried buffer retained above the MWWT – like EVERY OTHER QUARRY where drinking water supplies are at risk.
 

Thursday, 22 April 2021

AI’s infiltration plans completely unworkable – revised MWWT contours show

The issue of surface water management is critical at Straitgate Farm if any quarrying is to be permitted. In 2015, Devon County Council warned
The surface water management is inextricably connected to Flood Risk Management/Airport safeguarding and the need to maintain and recharge watercourses. This issue is so important in terms of the likely significant impacts of the proposal the MPA would wish to ensure that a SWM scheme can be designed to meet all of the requirements identified in advance of the determination of this application. 
In 2017, in its Regulation 22 request, Devon County Council asked: 
The surface water management strategy should identify location of the infiltration features and how these fit into the site; It should be confirmed how the water will be collected in the catchment for these headwaters to supply the stream heads (bearing in mind airport safeguarding requirements) and the proposed phasing of the site. This should include detailed design regarding their size, details whether infiltration is permitted at the proposed locations and where targeted at areas where infiltration is required to support the spring lines of the existing watercourses (as commented by the Environment Agency), together with details of exceedance pathways. Due to the nature of the flood risk downstream, greenfield performance should be achieved and the site should be designed to the worst case scenario as detailed in the FRA and should ensure that drainage from the site mimics, as closely as possible, the natural hydrograph in perpetuity. The MPA will wish to have it demonstrated that the applicant has engaged with the LLFA, the EA and the Airport to design a scheme that can accord with all of their various requirements. 
2.18.2 Figures A2.1, A2.2 and A2.3 in Annex C of the submitted Surface Water Management Plan, provided in Appendix C of the Flood Risk Assessment (FRA) (Amec Foster Wheeler document reference: 33679rr145i4) details the proposed areas of the void base for phases 1, 2 and 3 where runoff will collect as it infiltrates. The figures show the sub-catchment divides, where gradient parallel bunds and contouring will be required to ensure the proportion of runoff draining to different sub-catchments remains the same during the extraction process (i.e. it is targeted to the required sub-catchment). 
We have posted before that Aggregate Industries' infiltration plans were unworkable. 

Since then, the maximum winter water table contours have been revised, and the problem has become more apparent. Whilst existing ground elevation contours run parallel to the eastern extraction boundary, the base of any quarry as defined by the newly revised MWWT contours would not. 

As shown above – where the infiltration areas overlay the revised MWWT contours – the proposed base of extraction in the areas set aside for infiltration in phases 1 and 2 does not mimic ground elevations to maintain pre-extraction infiltration characteristics. In phase 2, for example, the base of extraction in the infiltration area falls from 140mAOD to less than 135m.

Surface water running off the extraction site would not infiltrate equally along the eastern extraction boundary. In phase 2, run-off would flow to the north-east, directing water away from the Cadhay Wood stream, the stream feeding Cadhay's mediaeval fishponds, and away from the Cadhay spring, the spring supplying drinking water to Grade I listed Cadhay and a whole host of others. In phase 1, water would be directed towards the middle of the infiltration area. 

How much water are we talking about? This table is from the Flood Risk Assessment.
 

Of course, this not only has implications for flooding, springs, stream flows and airport safeguarding, but also for the resource available – freshly cut to 1.06 million tonnes.


Monday, 19 April 2021

AI’s Transport Assessment is riddled with errors and fatally flawed

How much care has gone into the new documents supporting Aggregate Industries’ planning application to quarry Straitgate Farm, the ones now subject to public consultation?

Has anybody at Aggregate Industries bothered to check them? It certainly doesn’t look like it. It’s almost as though the company can’t be bothered any more. 

Take the newly supplied Transport Assessment. This is the company’s third transport assessment since 2015, from its third set of traffic consultants. This one is from Horizon Consulting Engineers Ltd. It may be newly supplied, but it’s not newly written. It’s dated July 2018. The traffic count is almost 3 years old; collision data more than 4 years old. 

It’s been through some changes too. As submitted, it stands at Revision E which claims:
1.1.8 It has been agreed with the Tenant farmer... that there will not be a need to intensify livestock crossings over the B3174 Exeter Road...
It’s a big claim. And a big lie. No agreement, legal or otherwise, has been presented in the Transport Assessment or elsewhere other than an email from the farmer’s land agent which finishes by saying "these movements would need to occur daily." This email was added in Revision D of the document, replacing an unsigned Joint Statement authored by Aggregate Industries. Why? Revision C tells us that "the Tenant Farmer has been advised by their Solicitor and Agent not to sign the document", which will sound to most normal people as not agreed

Devon County Council wrote to Aggregate Industries in November 2017, saying:
... in order to assess the potential highway safety impacts the MPA needs to have reliable information on existing and potential agricultural crossings of the Exeter Road and, in particular how this would be controlled in the future in the interests of highway safety.... 
If we do not receive this information in full I cannot address the likely highway safety impacts in any report to the County Council’s Development Management Committee. 
But neither Aggregate Industries nor Devon County Council can tell the farmer how to run their business. There are no laws preventing farmers herding livestock across or along roads. The highway authority has no explicit powers to prevent a farmer doing so. As long as it's done safely, with crossing points washed down, if the farmer needs to put cows across the road to sustain their business then they can do so. It happens all over Devon.

Moreover, within reason, the farmer can take whatever time it takes to move the 150 cows across the B3174 Exeter Road and clean up afterwards. 

Some cows can’t be hurried, despite what Aggregate Industries’ traffic consultant claims. Revision D in March 2019 was updated to Revision E in June 2019. The only substantive change
3.2.6 Dairy herds of similar size have been observed at other farms in Devon crossing a similar distance, without splitting the herd, in 4 minutes. 
Really? And how long did the traffic consultant scour Devon looking for such herds? Or was it the task of an Aggregate Industries’ operative? Or was it no one? In any case, it’s immaterial. Cows will take whatever time cows will take; 150 cows from this Devon herd would certainly not take 4 minutes:

 

So the Transport Assessment is fatally flawed. It has not assessed the impact of the additional cattle that would have to cross the B3174 Exeter Road as a direct consequence of the planning application, an application that seeks to remove almost 90% of pasture for mineral extraction and associated infrastructure. It has not assessed the impact on the functioning of the road network, including the A30. It has not assessed the impact on safety. 

What other clangers are there? The usual inconsistencies: 
4.1.1 Over an eight to ten year period it is proposed to extract circa 1.5 million tonnes of ‘as-raised’ sand and gravel... 
5.1.1 Sand and gravel extraction at Straitgate Farm is proposed... over an estimated 10 to 12 year period.
Which is it? On the risk to school children: 
5.5.6 To address the identified risk to students of HGV’s the Applicant has agreed to an embargo during term time on HGV movements between the hours of 08:05 and 08:30 in the AM peak... 
3.2.11 A site visit was undertaken... The coach arrived at 8.36 am
Brilliant. On site access: 
4.2.1 The purpose of this report is not to revisit the previously discounted access points... 
Of course not. Want to know why? Previously, Aggregate Industries had dismissed the very site access it is now promoting
5.44 The southern option, onto the B3174, was dismissed early in the process on highway safety grounds.
On being so out of date, events have already superseded it: 
5.5.10 ...the Applicant would assist the Tennant [sic] in submitting an application for an agricultural access 
Aggregate Industries submitted such an application to East Devon District Council last December, not as some kindly act of assistance, but to facilitate its quarry plans. 

On accidents: 
3.2.32 ...No collisions involving HGV’s [sic] have occurred within the three year period... 
That’s based on 5 years of data up to 31 December 2016. What about since then? Devon County's map is now "displaying collisions between 01/01/2016 and 31/12/2020"? 

Aggregate Industries wants to haul material along the B3174 to the A30 Daisymount Junction. So why not assess that stretch? Why assess just this little area? 


Is it because when consultants looked further they discovered this fatal accident? 

And regarding that business about "No collisions involving HGV’s", well that obviously overlooks this little incident in April 2016


And we all know how many accidents there have been since then – including HGVs – on this stretch of the B3174 Exeter Road, where Aggregate Industries wants to put up to 216 HGV movements per day. There’s even a label – B3174 accident – on the side of this blog pointing some of them out. 

Which makes this Devon County Council internal email – released through an FOI request – all the more embarrassing: 

And where are we now? Going out to yet another consultation, seeking comments on a document riddled with errors. Do Aggregate Industries and Devon County Council think local people have nothing better to do with their time than waste it on mineral consultations, going through error-riddled-document after error-riddled-document, pointing out problem after problem, problems that should have been ironed out BEFORE seeking their views? 

After all, it’s not as though Aggregate Industries hasn’t had the time.