Airport objects to planning application for single dwelling & pond next to Straitgate

This week, against officer recommendation, East Devon District Council refused planning application 24/1278/FUL Construction of a new dwelling and associated landscaping | Land Adjacent Upper Spilsby Exeter Road Ottery St Mary – on an area of land adjacent to Straitgate Farm – for two reasons, the second of which was: 

2. It has not been demonstrated that the development would not attract wildlife to the area which could result in a health and safety hazard to users of Exeter Airport contrary to Policy TC12 (Aerodrome Safeguarded Areas and Public Safety Zones) of the East Devon Local Plan, 2015 to 2031 

Exeter Airport’s Airfield Operations and Safeguarding team had objected twice to the application, firstly in July 2024 stating: 

The development is situated within an area of higher ground in the Type A airspace. The creation of new permanent water bodies risks the increase of bird activities within the airspace.

The applicants commissioned a Technical Note in response to Exeter Airport’s objection – pointing to the larger body of open water left by Aggregate Industries at nearby Rockbeare Quarry, and also pointing to the company’s plans for Straitgate Farm approved at appeal. The Technical Note stated: 

The application site is also adjacent to an approved quarry application site (Figure 8). Exeter Airport concluded that the proposed quarry does not appear to conflict with safeguarding criteria subject to a number of conditions (refer to Figure 9). This is despite the creation of ‘ephemeral waterbodies and species-rich wet grassland to be encouraged in low-lying infiltration areas’ (refer to Figure 10), which are more likely to attract conflict species, such as gulls, geese and other waterfowl than the proposed ponds at the application site. 

Nevertheless, Exeter Airport maintained its objection, stating: 

The development is located within the aerodrome safeguarding area in a position on high ground located within the type A airspace. Due to the development's location and AMSL height any potential increase in bird activities cannot be supported and must be mitigated by way of a wildlife management plan. 

 Exeter Airport has received and reviewed the provided assessment of Birdstrike. While this is accepted as an assessment of potential risk it is not accepted as a wildlife management plan and as such maintains its holding objection till a wildlife management plan is submitted to negate the potential risk of increased bird activities in the airspace. 

This is supported as stated in the provided report by ASAN3 as a building development that has manmade landscaping features that have the potential to attract flocks of birds and/or large birds. 

The report makes note of DCC/3944/2017 planning application for Straitgate Quarry as a reference in the area. Straitgate Quarry has a robust provided wildlife habitat management plan (WHMP) including planning conditions of routine site visits, onsite pumping equipment and no new permanent bodies of water to be created therefore can not be used as evidential reasons for the creation of new permanent water bodies within the area. Also, of note straitgate Quarry is situated at lower ground level to proposed development. 

While as report has stated the development is low risk in creating a risk of birdstrikes action must still be taken to negate all risk to aircraft within the area due to the potentially fatal consequences. The aerodrome is happy to provide reference and contacts to assist in the creation of the required Wildlife Management Plan.

Is Exeter Airport holding individuals seeking permission for dwellings to a higher standard than international quarrying conglomerates? 

Exeter Airport did not maintain an objection to Aggregate Industries’ plans for Straitgate Farm, which also sits directly below the landing approach for the Airport, despite the planned creation of water bodies for surface water management and restoration.

       

To allay the Airport’s original concerns, Aggregate Industries commissioned a Wildlife Habitats Management Plan for the site. Nevertheless, Planning Inspectors, in granting permission, conditioned that the site can only be quarried if:  

25. No water body shall be created within the site other than the approved weigh bridge lagoon.  

The reason for this was set out in the condition in its draft form (20): 

To prevent the site becoming attractive to flocks of birds that may lead to an aviation hazard in the interests of public safety and in accordance with Policy M20 (Sustainable Design) of the Devon Minerals Plan. 

Of course, the area of potential open water that would be introduced by quarrying Straitgate Farm is many times greater than what was proposed by planning application 24/1278/FUL.

What exactly is a water body?

Although the creation of temporary water bodies – for surface water management and restoration – is shown on Aggregate Industries’ plans to quarry Straitgate Farm, Planning Inspectors conditioned that the site can only be quarried if: 

25. No water body shall be created within the site other than the approved weigh bridge lagoon. 

The reason for this was set out in the condition in its draft form (20):

To prevent the site becoming attractive to flocks of birds that may lead to an aviation hazard in the interests of public safety and in accordance with Policy M20 (Sustainable Design) of the Devon Minerals Plan.

Straitgate Farm sits directly below the landing approach for Exeter Airport.

 

Condition 25 is unequivocal. 

It is not weakened by an unless otherwise agreed tailpiece. The Inspectors strengthened the draft condition by removing "without the prior written approval of the Council...".

It is not limited by size. The Inspectors did not specify any minimum. 

It is not limited by duration. The Inspectors removed the qualifier permanent from the draft condition after hearing how temporary water bodies can attract seasonal birds. 

What exactly is a water body? Lawinsider says: 

Waterbody means any accumulation of water, surface or underground, natural or artificial, including rivers, streams, creeks, ditches, swales, lakes, ponds, marshes, wetlands, and ground water. 

Wikipedia says:

The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rarely, puddles.

Puddles? Apparently so. In 47 Types Of Bodies Of Water: Pictures And More, Puddle sits at No. 31. 

In fact, in Puddle Britain: 11 amazing facts about tiny bodies of water, Prof Jeremy Biggs, the CEO of the Freshwater Habitats Trust, author of the book Ponds, Pools and Puddles, explains when a puddle becomes a pond, or, for that matter, a lake:

In the UK, we call everything up to 2 hectares [about 5 acres] a pond, but a lake that’s 2.1 hectares is really no different from a pond that’s 1.9 hectares. Down the bottom end, we call things down to 1 sq metre a pond, so then it’s below that we have puddles.

🔵 What is a puddle?

🟡 When does a puddle become a pond? Or, for that matter, a lake?

🔵 Can anything live in a puddle?

🟡 Can animals survive in puddles?

Discover 11 facts about these bodies of water with @guardian ⬇️https://t.co/MODLYxySaZ

— ipbes (@IPBES) November 30, 2023

What hope does Aggregate Industries have of controlling puddles – if it can’t even control this? 

Indeed, what hope does Aggregate Industries have of not creating any new bodies of water, when Google Earth images confirm they were introduced at all of the company's other BSPB quarries? 

As we've said before, the company's plans for Straitgate are incompatible with Condition 25.

But perhaps Aggregate Industries has a cunning plan. 

Why does all this matter? Aggregate Industries left water bodies at nearby Blackhill Quarry – and these were some of the visitors that arrived.

It was Canada geese that brought down US Airways Flight 1549.

AI’s ponding problems at Hillhead worsen – attracting ducks & gulls too

Aggregate Industries’ plans for Straitgate Farm positively encourage the creation of water bodies – for surface water management and restoration. However, for Airport Safeguarding reasons, the Planning Inspectors only granted permission to quarry Straitgate on the condition that: 

25. No water body shall be created within the site other than the approved weigh bridge lagoon.  

As we posted a year ago: 

This condition... is clear and unambiguous. It is not limited by the size or duration of any water body – large or small, permanent or temporary.  

We have since posted We all know Aggregate Industries will have difficulty complying with Straitgate’s ‘no water body’ condition – Google Earth images confirm why. 

In June last year, we posted – here and here – about the ponding problems Aggregate Industries has suffered at Houndaller quarry at Hillhead, near Uffculme, where the company is extracting the same type of sand and gravel available at Straitgate. 

What’s the scale of the problem? Devon County Council's monitoring report for Hillhead Quarry in 2022 provided this photo:

The latest monitoring report for the site issued this week reveals that the ponding problems remain ongoing and are slowing down restoration: 

4.16 ...The water is ponding in this Phase and the operator would like to direct this water to Houndaller Pond, north of the farmhouse, in order to complete restoration. Therefore, a non-material amendment was submitted in order to alter the phasing of working. The has resulted in the operator entering the western end of Phase 8 to allow water to move from Phase 6, into Phase 7 and 8 temporarily whilst restoration is under way. Originally, working in Phase 8 was to commence at the eastern end. Alterations to allow water to enter Houndaller Pond will need to be subject to a full application. 

4.17 Despite the ponding, work has begun on restoring Phase 6 at the eastern end to the final restoration levels. It is anticipated this will be completed in 2025, however, it is understood the ponding is slowing this down... 

The report didn't say if the ponding problem had worsened. However, photos taken this week, above and below, show that it has:

Furthermore, the water is attracting ducks and gulls – the sort of species that would be particularly hazardous at Straitgate, being just 200m below the landing approach for Exeter Airport.

Even without its plans that encourage water bodies at Straitgate, Aggregate Industries’ problems at Hillhead – and the ponding at its other sand and gravel sites in Devon for that matter – demonstrate the company hasn’t a ghost of a chance of complying with condition 25 at Straitgate.

We all know Aggregate Industries will have difficulty complying with Straitgate’s ‘no water body’ condition – Google Earth images confirm why

One of the first posts on this blog, back in 2012, asked: Could Straitgate be quarried without water? 

We noted that Exeter Airport's request that "no ponds or body of water be allowed as part of this development" to ensure aircraft safety from bird strikes, would surely be an impediment to any scheme. 

And indeed this impediment has now been formalised.

Earlier this year, the Planning Inspectors, in granting permission to quarry Straitgate Farm, conditioned: 

No water body shall be created within the site other than the approved weighbridge lagoon. 

As we posted in January, this makes Aggregate Industries' plans for Straitgate incompatible with the Inspectors’ planning conditions, given that the company's approved plans rely on the formation of water bodies – both for flood mitigation and for restoration. As we wrote, the Inspectors' condition: 

...is clear and unambiguous. It is not limited by the size or duration of any water body – large or small, permanent or temporary.  

What exactly is a water body? As we previously posted: 

Wikipedia says "The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rarely, puddles." LawInsider goes further. This helpful graphic also explains.  

In that 2012 post, we wrote about Aggregate Industries' nearby sand and gravel quarries at Blackhill and Hillhead, quarries that extracted the same type of material from the Budleigh Salterton Pebble Beds that would be extracted at Straitgate Farm. We wrote that Google Earth images: 

...reveal several bodies of water in each and it is inconceivable that Straitgate, particularly with all its water related issues, could ever be quarried without the formation of ponds or lagoons of some kind.

In fact, Hillhead suffered ponding problems only this year. 

Further back, we posted how the water body at Aggregate Industries' quarry at Thorn Tree Plantation at Blackhill was meant to be ephemeral but is instead present all year round. 

The company's quarry at Venn Ottery also suffered ponding issues. 

Hanson’s Town Farm Quarry works the same type of material and also has bodies of water. 

But let's build on that 2012 post, and, using Google Earth’s historical imaging, look at all five BSPB quarries in Devon that have been worked in recent times. The images below show the quarries at Venn Ottery, Marshbroadmoor at Rockbeare, Thorn Tree Plantation at Blackhill, Houndaller at Hillhead and Town Farm, at a time when extraction was actually underway. 

Venn Ottery

Marshbroadmoor

Thorn Tree Plantation

Houndaller

Town Farm

Clearly, sizeable new bodies of water were introduced at all of them.

So, even if we were to overlook Aggregate Industries' flood mitigation and restoration plans for Straitgate – that actually encourage water bodies – the above images underline, if any more underlining were needed, just how unworkable the whole scheme really is. 

Mineral extraction scheme causes birdstrike concerns at RAF Fairford

We have previously posted about RAF Fairford and the threat of birdstrikes from nearby mineral works.

French Air Force Mirage 2000 makes emergency landing at #RIAT15 #RAF Fairford after a bird strike. Landed safely pic.twitter.com/BB0n0b0pob

— Røbbø 🇬🇧🇨🇦 (@Ravenser) July 19, 2015

No wonder the MOD expressed concern over a nearby quarry proposal 21/0032/CWMAJM at the former RAF airfield at Down Ampney in the Cotswolds, 3 miles south west of RAF Fairford. 

Bid for new quarry raises concern for RAF Fairfoldhttps://t.co/Egx6Okarua

— Greatest Hits Radio Gloucester (@GHRGloucester) September 23, 2023

The MOD wrote: 

The development proposed entails the stripping of topsoil, the extraction, working and storage of minerals, and the phased restoration of the site. 

Each of these activities have the potential to create an environment that would be attractive to those large and/or flocking bird species hazardous to aviation safety. 

The applicant has acknowledged that aircraft passing close to the application site, approaching or departing RAF Fairford, are likely to be at altitudes of less than 1,000ft above ground level and would be within the range of altitudes where 90% of birdstrike events take place. 

The applicant and the MOD have conducted pre-application discussions. Through these discussions the MOD has made clear that restoration of the site which results in the creation of open water would be unacceptable as those waterbodies would likely provide an environment attractive to those large and/or flocking bird species hazardous to aviation.

Despite the MOD's concerns, officers recommended approving the scheme, to extract 6.5 million tonnes of sand and gravel over 13 years with a phased restoration scheme using imported infill, and, last month, the proposal was given the green light by Gloucestershire County Council, 9 votes for, 2 against – subject to the prior completion of a S106 planning obligation to secure the implementation of a Wildlife Hazard Management Plan. 

Here in East Devon, aircraft also fly less than 1000 ft above Straitgate Farm on their landing descent to Exeter Airport.

For Aggregate Industries' scheme at Straitgate, a Wildlife Hazard Management Plan was also stipulated, with planning inspectors conditioning that: 

No water body shall be created within the site

Of course, where Straitgate differs to the Cotswolds scheme is that restoration will not involve imported infill; Aggregate Industries will just dig a hole, and leave it. 

We have previously posted – given that water bodies are intended at Straitgate – that Aggregate Industries’ plans for the site are incompatible with the Inspectors’ planning conditions. 

This is even more concerning given the scale of Aggregate Industries’ (unintended) ponding problem at the company's nearby quarry at Hillhead.

What’s the scale of Aggregate Industries’ ponding problem at Hillhead?

If Aggregate Industries is to quarry Straitgate Farm, it must do so without creating any water bodies – for aircraft safeguarding reasons – as we have previously posted. 

Is that possible? Of course not. 

How can we be so sure? You only have to look at Aggregate Industries’ Houndaller quarry at Hillhead, near Uffculme. It has the same type of sand and gravel that exists at Straitgate Farm. We recently posted that Aggregate Industries has ponding problems at Houndaller, and that the company has now been forced to apply for permission to change the surface water management plan for the site. 

Last December, Devon County Council’s Monitoring Report for the site reported: 

4.15 Since the previous monitoring visit, Phase 6 has now been worked out and is awaiting grading and topsoiling… It is understood water is ponding in this Phase and the operator would like to direct this water to Houndaller Pond, north of the farmhouse in order to complete restoration.

 And the scale of the problem? The Monitoring Report helpfully provides this photo:

Oh look, Aggregate Industries suffers ponding problems at Hillhead

After many years of working its Houndaller quarry at Hillhead, near Uffculme, Aggregate Industries now wants to change the surface water management plan for the site – a site with the same type of sand and gravel that exists at Straitgate Farm – as this recent Scoping Opinion request PRE/1659/2023 to Devon County Council reveals: 

The approved restoration contours, Drawing No. 2285/ROMP/4C located within Appendix C, illustrates the site falling west to east, with a low point on the south-western boundary of the site. This is causing surface water to pond within the south-western part of the site (Phase 6). Therefore, Aggregate Industries are proposing to amend the surface water management plan for the site, to include a perimeter surface water drainage ditch running northwards from the south-west corner of Phase 6 along the western edge of the site into Houndaller Plantation Pond. There will be a slight amendment to the alignment of the final land form contours for Phases 6,7 and 8, to enable surface water to be shed to the perimeter surface water drainage ditch. 3.2.3 

Of course, it’s not unusual for surface water to pond at quarries. What quarry doesn’t have water? 

Even for Straitgate Farm, Aggregate Industries’ plans positively encourage water bodies – for its surface water management and restoration plans: 

ephemeral water bodies and species-rich wet grassland to be encouraged in low-lying infiltration areas (in the base of the depressions)

In fact, the creation of infiltration areas on the eastern boundary of the Straitgate site forms an integral part of the company’s flood mitigation scheme. At the Public Inquiry the Inspectors were told by Aggregate Industries’ hydrogeology witness that standing water will remain in these areas for up to 15 days in the summer and 24 days in the winter.

However, and as we have previously posted, the Planning Inspectors stipulated – for aircraft safeguarding reasons – that: 

25. No water body shall be created within the site other than the approved weigh bridge lagoon. 

Bizarrely, therefore, Aggregate Industries’ plans for Straitgate cannot be implemented without breaking one of the planning conditions. 

As we remarked: 

This condition, which Aggregate Industries must comply with if it is to quarry Straitgate Farm, is clear and unambiguous. It is not limited by the size or duration of any water body – large or small, permanent or temporary. 

The company's inability to control surface water at Houndaller, highlights the problem: How will Aggregate Industries be able to comply with condition 25 at Straitgate ?

AI’s plans for Straitgate incompatible with Inspectors’ planning conditions

The Planning Inspectorate has granted Aggregate Industries permission to extract sand and gravel at Straitgate Farm – despite the fact that the company’s approved plans cannot be implemented without one of the imposed conditions being broken.

It has long been recognised that mineral extraction at Straitgate could introduce bodies of water directly below the flight path of Exeter Airport, thereby increasing the risk of birdstrike. In 2012, Exeter Airport wrote to Devon County Council with its concerns: 

As you are aware, the risk of a bird strike on an aircraft can be catastrophic, and as a result all aviation stakeholders do all possible to mitigate against this happening. 

Under the Air Navigation Law, it is a criminal offence to endanger an aircraft or its occupants by any means. 

The creation of any body of water, particularly on a long term basis, has the potential to create a suitable habitat which encourages an increase in bird activity for nesting, feeding and migration. 

Due to the location of the proposed quarry, it is felt that there is a real risk to aircraft if there is an increase in this area.

In light of these concerns – documented as a constraint in the Devon Minerals Plan – conditions relating to Airport Safeguarding were recommended in the Officer’s Report in 2021. 

However, based on comments made on the last day of the Public Inquiry, the condition relating to Airport Safeguarding and the creation of water bodies was strengthened by the Inspectors. It now reads: 

25. No water body shall be created within the site other than the approved weigh bridge lagoon.  

This condition, which Aggregate Industries must comply with if it is to quarry Straitgate Farm, is clear and unambiguous. It is not limited by the size or duration of any water body – large or small, permanent or temporary. 

What exactly is a water body? Wikipedia says "The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rarely, puddles." LawInsider goes further. This helpful graphic also explains. 

How easy would it be to create a water body at Straitgate? Fortunately, we know. Aggregate Industries’ archeological investigations were held up in October 2014 because water in the archaeological trenches would not drain away. 

We also know that Aggregate Industries has form in creating water bodies that attract birds elsewhere at their sites in Devon – just click on the labels airport safeguarding or birdstrike, or these posts here, here, here, here, here and here. Below is a photo of a water body left by the company at Hillhead:

But let’s put all that to one side for a moment. 

One of Aggregate Industries’ approved plans – listed in the Planning Inspectors’ report as Restoration Scheme SF/6 rev E – actually encourages water bodies: 

EPHEMERAL WATER BODIES AND SPECIES-RICH WET GRASSLAND TO BE ENCOURAGED IN LOW-LYING INFILTRATION AREAS (IN THE BASE OF THE DEPRESSIONS)

As low points in the quarried landform, water bodies might be expected to form in these areas. But Aggregate Industries says they are needed for surface water management reasons too: 

The features are part of site restoration to ensure the site is restored to baseline conditions with some betterment. The features allow the restored site to mimic natural conditions, but ensure a greater proportion of rainfall passes to ground to provide flow support to the watercourses, rather than passing off-site as overland flow. 2.18.7 

In addition to that, the creation of infiltration areas on the eastern boundary of the site is an integral part of the company’s flood mitigation scheme. At the Public Inquiry the Inspectors were told by Aggregate Industries’ hydrogeology witness that standing water will remain in these areas for up to 15 days in the summer and 24 days in the winter. Of course, if it rains again in the meantime – as it often does – the duration will be extended. 

So – there is a contradiction. Aggregate Industries’ plans rely on the creation of water bodies, which the Planning Inspectors’ conditions prohibit. 

In other words, Aggregate Industries’ plans cannot be implemented without the conditions being broken. 

One might ask why the Planning Inspectors granted permission for a scheme that was incompatible with their conditions. Whatever the reason, it would appear there was more concern with approving Aggregate Industries’ scheme than there was in seeing whether it could actually work.

AI’s revised plans, unworkable drainage scheme & exaggerated infiltration rates would leave PERMANENT water bodies below Exeter Airport’s landing approach

Photographs of Canada Geese at Aggregate Industries’ nearby Blackhill Quarry on the aptly named Seagull Pond can be found at the top and bottom of this post.

Canada geese are one of the more dangerous bird species for aircraft to strike because of their large size and because they travel in flocks of up to several hundred birds.

In 2017, in response to Aggregate Industries’ application to quarry Straitgate, Exeter Airport wrote:

Exeter Airport have no safeguarding objections to this development providing that the... conditions are adhered to at all times and there are no changes made to the current application. 

One of those conditions was: 

No new permanent bodies of water should be allowed on the site without prior consultation.

Permanent bodies of water like Aggregate Industries left after quarrying nearby Thorn Trees Plantation:

Permanent bodies of water like Aggregate Industries left after quarrying nearby Venn Ottery – as shown in the Council's latest monitoring report: 

Earlier this year, Exeter Airport wrote: 

Exeter Airport have no safeguarding objections to this development provided there are no changes made to the current application and that the previously submitted Wildlife Hazard Management plan is adhered to at all times.

On the proposed infiltration areas to contain flooding, the WHMP says: 

The primary purpose of ditches is to prevent flooding. These ditches reduce the amount of water ponding, therefore reducing the amount of food and habitat available to wildlife. They are critical in reducing the duration that critical areas are inundated for. This in turn reduces the amount of seasonal habitat for water birds and waders.

The problem is, there have been changes made to the current application, such that these drainage ditches or infiltration areas cannot work. Surface water runoff would not infiltrate evenly along the eastern boundary, given the revised gradient of the proposed extraction base, but would instead collect in the low areas. The ditches could not be accommodated where specified without breaching the maximum water table. Furthermore, the Environment Agency's drainage condition that "the working and restoration infiltration design shall ensure that drainage mimics the pre-excavation drainage" cannot be satisfied, given that the base of any quarry, the revised MWWT – the contours which would define, in perpetuity, a large part of the restored landform – do not mimic the existing topography. 

The Flood Risk Team has objected on the basis that "the applicant has not submitted sufficient information in order to demonstrate that all aspects of the surface water drainage management plan have been considered." 

Exeter Airport will be unaware of all of this. Exeter Airport will also be unaware that Aggregate Industries has, according to Professor Brassington, exaggerated the infiltration rates used in the design of these drainage ditches. The Flood Risk Assessment – which is now more than four years old and has not been informed by the elevated groundwater levels recorded, or the revised MWWT contours – has assumed unrealistic infiltration rates. Appendix C 2.2 says:

Infiltration rates of 1m/d (0.0416 m/hr) were applied to the infiltration ditches/ponds...

Professor Brassington warns: 

The soakaway tests carried out did not allow an infiltration rate to be determined using the BRE approach although the fall in water levels suggested a permeability in the order of 0.60 to 0.90 m/d. In my opinion, these results cannot be reliable because the loosely replaced broken-up material in the trial pit will not have been trafficked by heavy machinery in the same way that the proposed replaced layer would be. In any event, the tests were hardly conclusive as the comment was made ‘Insufficient drop in water level. Unable to calculate infiltration rate’. This does not suggest a permeability as high as 0.60 to 0.90 m/d, indeed, it could easily be in the range 0.06 – 0.09 m/d or even lower.

A lower infiltration rate will obviously affect the capacity that must be set aside to contain surface runoff. 

Exeter Airport has been consulted on unworkable, exaggerated, out-of-date information.

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, here, here 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. 

In 2015, the Environment Agency said: 

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. 

In 2017, the Environment Agency was concerned that the company had not resolved the issue: 

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.

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. 

In answer, Aggregate Industries said: 

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.

AI’s latest plans for Marshbroadmoor & Rockbeare in trouble already

Oh dear. Aggregate Industries’ plans to import some 200,000 tonnes of materials that "will consist mainly of subsoils and clays" – as part of its proposal to restore Marshbroadmoor to "areas of mixed woodland" – have come unstuck already. Only last week, we posted about the company’s plans for the sites in AI launches another retrospective planning application.

You would have thought – given that the company has already had airport safeguarding issues with its planning application to quarry nearby Straitgate Farm – that AI would have learnt by now not to propose tree planting on a hill top location directly below the landing path to an international airport.

In 2014, we posted Presumptuous? after AI started planting trees at Straitgate. We said:

Aggregate Industries does not have permission to quarry Straitgate Farm; in fact, the farm is not even in Devon's Minerals Plan. This hasn't stopped AI from starting to mark out where it wants to quarry, with fencing and the planting of tree screens, according to its 'concept plans' - plans not agreed by anyone other than its consultants; not DCC, not the Environment Agency, not Natural England, not Exeter Airport…

And indeed it was presumptuous. Because in 2015, Exeter Airport said:

No trees or hedges must be planted to the west or south of the site. The land in this location already penetrates the OLS and any further penetrations would be unacceptable. Ideally any existing penetrating trees should be removed over time. Any tree and hedge planting should be restricted to the far eastern side of the site and below the 135mAOD contour ensuring trees are not allowed to grow to a height that will cause OLS penetration issues in future years.

Again in 2017 – plainly because AI still hadn’t got the message – Exeter Airport advised:

Tree management and planting should be carried out following the guidance in the attached EDAL tree planting plan to ensure no further penetrations of the Obstacle limitation surfaces.

And so, in 2018, the majority of trees AI had planted at Straitgate – in an effort to provide compensatory habitat for dormice, for all the ancient hedgerows it plans to grub up – were cut down. We posted AI cuts down ‘compensation’ planting; so where does that leave protected species? As we wrote:

It’s a shambles. If we can’t trust AI to do a simple job like managing tree planting in the right place, how can we trust it to dig in the right place, or more specifically for the protection of people’s water supplies, dig to the right depth?

Clearly AI didn’t learn. Its restoration plans for Marshbroadmoor proposes planting areas of woodland higher than 135mAOD, and again Exeter Airport has objected:

The landscaping proposals in this planning application are on ground that is directly below the take-off and climb and approach surfaces for Exeter airport. The land here already penetrates some of the airports safeguarded surfaces which are in place to protect the safe manoeuvring of aircraft in the area and ensure no adverse effects to instrument landing systems.

Any additional tree planting and landscaping works in this area have the potential to further increase the surface penetrations that Exeter Airport already suffers, over time these penetrations should be reduced, and also increase the risk of birdstrike to aircraft that are in a critical phase of flight as they pass over this location either on approach or departure…

A robust Wildlife Hazard Management Plan to include Landscape and Tree maintenance would need to be supplied and approved by Exeter Airport to ensure there is no increase in risk of birdstrike to aircraft and that there would be no further surface penetrations by trees either now or in perpetuity.

Accordingly, Exeter Airport object to the proposal on the grounds of aviation safety.

‘Proposed quarry could affect safety of flights at Airport’

RAF Boeing C-17 Globemaster flying low over Straitgate Farm

Perhaps they have higher standards in New Zealand, where Christchurch International Airport (CIAL) and Air New Zealand say a proposed quarry poses a risk to passengers and pilots from the increased probability of bird strike:

In its submission, CIAL says the proposed quarry "is likely to have more than a minor adverse effect on the safe, efficient and unrestricted operation" of the airport. Ponds for quarry wash and sediment treatment, along with puddles after heavy rain, could attract seagulls and other scavenging birds, "increasing the risk of bird strike". The proposed quarry was also in line with the centre of the main northeast-southwest runway and as a result directly beneath the flight path for arriving and departing planes.

Air New Zealand says it opposes the quarry development for the same reasons. "The risk of bird strike occurring is increased by factors such as bird concentrations as a result of storage of water on sites near to flight paths. Bird strike has the potential to cause serious damage to aircraft and consequently impact the safety of passengers and crew."

Exeter Airport has not objected to quarry proposals at nearby Straitgate Farm, directly below its landing approach –

– but then again they were spun a story from Aggregate Industries that no bodies of water would be created by its quarry proposals; Aggregate Industries being the same people who plan to dig down to the maximum water table at the site, but have not yet been able to work out exactly how high the groundwater rises, the same people whose infiltration ponds can't work in the areas proposed because the groundwater is so close to the surface, the same people whose restoration plans propose "Ephemeral water bodies and species-rich wet grassland to be encouraged in low-lying infiltration areas", the same people who made similar assurances about dry-working elsewhere in the area.

Holidaymakers returning to Exeter Airport, flying low over Straitgate Farm

Canada geese flying over AI’s nearby Blackhill Quarry: