Carbon sink – conservation management at Munsary, Plantlife’s peatland nature reserve

Sunday 27th of July was International Bog Day, and the charity Plantlife re-released a You Tube video from a conference pre the Glasgow COP in 2021, about the peatlands on their reserve at Munsary part of the Flow Country in Sutherland. While this blanket bog may seem a million miles away from Walshaw in its scale and utter remoteness it’s a really good listen, and goes into some depth about peaty science.

Penny Price
Upper Calderdale Wildlife Network

Latest government policy and what it means for Walshaw Moor and CEP

In July 2025 the government paper “Unlocking benefits for people, nature and climate: Actions to jointly address climate change and biodiversity loss in England” was published. In this article we will work out what it means for Walshaw Moor.

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It is very good news for the curlews and golden plovers, merlins and lapwings and for the habitat that they need to flourish on Walshaw Moor. Almost everywhere these birds are in steep decline because their breeding grounds have been destroyed by mismanagement. Walshaw Moor is a glittering exception. 

The foreword to the paper is crucially written by the two key ministers: 

Mary Creagh MP Minister for Nature for Department of Environment, Food and Rural Affairs  

Kerry McCarthy MP,  Minister for Climate for Department of Energy Security and Net Zero. 

For the first time we see a government that understands that we are in a Nature and Climate Crisis. England (conservation is devolved) is one of the most nature-depleted countries on Earth. 

The paper begins with international treaties we have signed and often led. The British people are famous nature lovers and our governments have always tried to lead the world into looking after nature properly.  The problem has always been that we are nature hypocrites: “Do as I say, not as I do!” While we tell other countries what to do with their elephants, pangolins and whales, our own nature is battered. Calderdale Energy Park will batter the extraordinary birds that breed so successfully there but are being picked off elsewhere. 

The greatest triumph in international nature diplomacy is the Kunming-Montreal Global Biodiversity Framework, signed by 196 nations in 2022. It has been hailed as a “huge, historic moment” and a “major win for our planet and for all of humanity.” As the new government paper says:

“The 30 by 30 commitment, to effectively conserve and manage 30% of our land and seas by 2030, sits at the very heart of the UK’s aim to ensure nature’s recovery. Delivering this target means ensuring that the most important and wildlife-rich habitats are benefiting from effective, long-term conservation and management. At CBD COP16 in October 2024, the UK confirmed its vision for delivering 30 by 30 in England and published the criteria for land and inland water areas which can count towards this target. At least 7.1% of England’s land has been identified that already meets the 30 by 30 criteria and counts towards the target. This includes Sites of Special Scientific Interest in favourable or unfavourable recovering condition, plus areas of the Public Forest Estate managed for biodiversity. While it is expected that there is additional land already meeting the criteria, such as NGO reserves, this illustrates the scale of action needed to achieve this target. An action plan for 30 by 30 on land is being developed, to ensure this commitment can be achieved. The aim is to finalise and publish this action plan later in 2025.”

The 7.1% is the internationally Special Protection Area and Special Areas of Conservation. The remaining 22.9% will be difficult, but at least we can rely on the international designations to anchor the plan. The map below shows in red the 7.1% of fully protected land that that counts, while the blue is land that might contribute to our 30% if it can achieve some legal protection for at least twenty years. 

 

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[Land in red counts toward the 30 by 30 K-M GBF commitment. The red areas are the SPAs or SACs and some areas are both. Exmoor is an SAC for its heathland habitats but is not an SPA. Dartmoor, like Walshaw Moor, is doubly designated for its habitats and birdlife. The map shows how important to the 7.1% are the Pennines. Walshaw Moor is shown by the arrow. Map: Defra]  

Walshaw Moor is a Special Protection Area (SPA) because it is the breeding ground of many red-listed birds, merlins, curlews, golden plovers and lapwings. These birds are nationally endangered, but are thriving on Walshaw Moor. 

Walshaw Moor is a Special Area of Conservation (SAC) for its peatland, blanket bog and acid grassland habitats. 

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[Calderdale Energy Park will destroy the centre of the South Pennines Moors Phase 2  SPA and SAC and fragment what is left. Since this land is in the 7.1% that is supposed to anchor the plan, the UK response to the 30 by 30 target would unravel on Walshaw Moor. The global south is already suspicious of British hypocrisy on nature. The worldwide policy would then also start to unravel on Walshaw Moor.   Map Nick MacKinnon and Defra Magic]  

Defra have defined how the blue areas can join the 7.1% that already includes Walshaw Moor. 

“30 by 30 areas should be able to demonstrate that in-situ conservation will be sustained over the long term (at least 20 years), and that the area will be protected against loss or damage to important biodiversity values, through legal or other effective means. This includes protected area designations, conservation covenants, long-term ownership and relevant long-term management obligations.”

Walshaw Moor is doubly internationally designated as SPA and SAC. It is in the heart of the South Pennines SPA/SAC. If it can be destroyed by a wind farm proposal just three years after a scoping report described as “worse than useless” by the lead consultant then the anchor 7.1% is unprotected, the “legal or other effective means” protecting the 22.9% are completely worthless and the UK response to the Kunming-Montreal GBF collapses. Since countries in the global south were reluctant to sign, feeling that the north had gained advantage in the past from destroying nature, this hypocrisy by the UK will cause the whole Kunming-Montreal agreement to unravel. 

“Unlocking benefits for people, nature and climate” shows for the first time that the government understands how the SPAs and SACs anchor our attempt to meet the 30 by 30 target, and will support the excellent work Defra have done since we signed the Kunming-Montreal treaty.  Walshaw Moor is likely to be the first major test of the resolve of our government to meet these international obligations for nature. We will either lead the world, or watch the policy unravel on Walshaw Moor.  

© Nick MacKinnon WTRG

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Will Calderdale Energy Park cause a repeat of the 1824 Bog Burst? 

The path of the 1824 bog burst from Stanbury Bog into Ponden Clough. The river of peat and boulders was up to five metres deep and was eventually ten kilometres long. The potential for a similar huge peat slide from the Sandy Moor section of the Option B access road to Calderdale Energy Park is shown. Thousands of 30-tonne tippers carrying crushed stone must come up this zig-zag track, followed by hundreds of abnormal loads of between 100 and 300 tonnes. The sideways traverse across the convex slope of Sandy Hill Moor is the most dangerous thing a track on deep peat can do. Off-piste skiers are killed every year in avalanches caused by their own weight as they traverse convex slopes like this. Map: WTRG
The site of Calderdale Energy Park between Burnley and Bradford. Map: WTRG On 2 September 1824, in a powerful rainstorm, Stanbury Bog burst, and a vast river of peat, water and boulders accelerated down Ponden Clough and charged past Ponden Hall. This blog will show in photographs the track of the 1824 bog burst. Anne (4) and Emily Brontë (6) had walked five miles from home when the bog exploded with such force that the bang was heard in Leeds. Their father Patrick heard it in Haworth and had to see out the storm at the Parsonage, not knowing if his young children would return from the moor with their helpers Nancy and Sarah Gerrs. Reverend Brontë based his next sermon in Haworth on this earthquake. “A rapid torrent of mud and water issued forth, varying from twenty to thirty yards in width and four to five in depth; which, in its course for six or seven miles, entirely threw down or made breaches in several stone and wooden bridges – uprooted trees – laid prostrate walls – and gave many other awful proofs, that, in the hand of Omnipotence, it was an irresistible instrument to execute his justice. Sometimes, God produces earthquakes as awful monitors to turn sinners from the error of their ways, and as solemn forerunners of that last and greatest day, when the universal frame of nature shall tremble, and break and dissolve.”
Hidden away near Ponden Kirk in the path of the Bog Burst is this carving: Emily Jane Brontë, August 20. 1835. Photo: John Page
Ponden Kirk is the rock buttress on the right. Raven Rock is on the bend in the Ponden Clough Beck on the left. The 1824 Bog Burst poured into this very steep natural amphitheatre and accelerated. Photo: John Page
The source of the bog burst. Looking south-east across Stanbury Bog towards Alcomden Stones on the horizon. This is exactly the same terrain that is at the top of Sandy Hill Moor. Photo: John Page
In 2025 we have had the driest Spring on record, and despite the Walshaw Moor Estate’s drainage schemes, Stanbury Bog still lives up to its name. It remains highly unstable and no paths have been established by walkers. Photo: John Page
The local geology is sedimentary, laid down in a shallow sea over 300 million years ago. It is in flat layers, like this like this wall. The wet and heavy peat has formed on top of the flat rock. The dividing line between the peat and the bed-rock sandstone is the shear plane and when it breaks on a convex slope the peat accelerates rapidly, and the terrain focuses the tidal wave into a wall of peat, water and boulders. Photo John Page

Looking across to Watersheddles Reservoir, from the edge of Middle Moor Flat over the possible route of the 1824 mudslide. Photo John Page

The torrent was up to five metres deep and large boulders were picked up and hurled through the air. The devastation can still be seen on the cratered moors today. For weeks afterwards, the Worth was full of dead fish. Ann Dinsdale, Principal Curator at the Brontë Parsonage Museum, narrates a short film of the event.

 

An 1824 Bog Burst crater. Photo: John Page

This huge boulder was carried here in the bog burst. Photo: John Page

The following year in 1825 The Edinburgh Journal of Science published an academic article by David Brewster : Notice of the Rare Atmospheric Phenomenon 1824 in which reference is made to the bog burst.

“Reports from Kelso, Berwick, Belford, Newcastle, and many places in Yorkshire and Northumberland, give accounts of a most alarming storm of thunder and lightning having occurred, accompanied with a’ vast quantity of rain, and spreading destruction over a great extent of the country.—Many men and domestic animals were killed by the lightning. It was during this storm that the subterraneous bog burst at Keighley in Yorkshire, which may be traced to the vast torrents of rain that seem to have accompanied the contemporaneous storm.”

Prior to the bog burst a period of high temperatures and dry conditions were followed by several days of exceptionally heavy rain. This would have led to a very large build-up of water in a dry Stanbury Bog, creating extremely unstable conditions in the deep peat overlaying the sedimentary bedrock. A slippery shear plane formed between the contrasting peat and sandstone, causing the the deep peat to slide down the convex slope. The mudslide would flow north-easterly under gravity into the steep sided valley of the Ponden Clough Beck. Fortunately there was no reservoir in 1824, for the force of the bog burst would have destroyed the dam, adding the reservoir’s water to a murderous torrent heading for Haworth.

Bog bursts are not uncommon. A lot of academic research has been done in recent years on them, and they are often caused by wind farm construction. The Irish Peatland Conservation Council wrote this:

“Bog bursts” or peat flows are a dramatic form of peat erosion. Sections of peat on sloped areas can break off from the main body of a blanket bog and flow down-slope, similar to a volcanic lava flow. Bog bursts usually happen after heavy rain on sites which have been put under human pressures, such as overgrazing, turf cutting or wind farm construction. For example, the construction of a wind farm at Derry Brien, county Galway resulted in a large bog burst causing almost half a square km of blanket bog to travel 2.5 km (Lindsay and Bragg, 2005). During a bog burst it is thought that the living plant layer of the bog tears due to stress and the very wet peat centre flows under the influence of gravity. Other bog bursts have been recorded in Ben Gorm in Connemara, on Clare Island in Co. Mayo and 52 separate bog bursts were recorded at Pollatomish, Co. Mayo”.

Film was taken of a small peat slide on relatively flat ground, caused by construction of Viking WF on Shetland.

Given that CWF Ltd presented such an unfinished proposal at their public consultation, we can have no confidence at all that any thought has gone into the potential for catastrophic peat slides on the north side of CEP.

The crest of the convex slope where Stanbury Bog begins to get steeper, dropping down into the Worth Valley. The boulder is not a glacial erratic, but was brought by the bog burst. Photo: John Page This history and geology of the 1824 bog burst is crucial for CEP because there are exactly the same geomorphological conditions to the north of Crow Hill Wague, in the catchment of the headwaters of the unnamed streams which flow down to Watersheddles Reservoir. This is where the Option B new road would go. A repeat of the September 1824 bog burst towards the top of the convex Sandy Hill Moor slope would wash away the new road, and fan out over Steeple Hill to clog up the small gorge leading into Watersheddles Reservoir, and Nan Hole Clough. If the bog burst were to follow the Nan Hole Clough valley then Wycoller could be destroyed.
These hummocks and groughs on the crest between Stanbury Bog and Bracken Hill are evidence of current instability in the peat mass. Photo: John Page © JOHN PAGE (WTRG)

Flooding and Calderdale Energy Park

Flooding and Calderdale Energy Park
Calderdale Energy Park is not a properly designed wind farm and it will greatly increase the risk of catastrophic flooding in the Calder Valley.

2015 flood in Mytholmroyd. Photo: BBC

The Calder Valley has suffered frequent devastating flooding, in 2012, 2015 and 2020.

The Walshaw catchment is already known to be very dangerous. This post will show how CEP will greatly add to catastrophic flood risk. Most of the time CEP will raise the runoff rate but will not cause a flood because river levels are low. Our analysis is always to do with storm outflow. CEP might only increase catastrophic flood risk on a few days every year, but when it does the risk is severely increased.
The Walshaw catchment focuses storm runoff into three exits that enter the Calder Valley. The catchments of the three exits are shown in the map below: Greave Clough, Walshaw Dean and Crimsworth Dean.

Storm runoff is focussed by the three Walshaw catchments: Greave Clough, Walshaw Dean and Crimsworth Dean. In Greave Clough there is a sluice which gathers the catchment and sends it down a tunnel to Widdop reservoir. In a storm the tunnel is overwhelmed and runoff goes over the sluice and directly to the Calder Valley. Map: WTRG

All CEP infrastructure accelerates storm runoff. Each turbine site has a buried concrete foundation and a crane hardstanding with an area of 0.5 ha, all with drainage ditches. The turbine sites are accessed by spur tracks, and the spurs are connected by a spine track and all tracks have drainage ditches. Cables run in buried concrete ducts along the spurs and spines. The spur tracks are the most important in flood risk during storms and peat destruction at all times. The spurs dry the peat by draining it. The CEP spur roads are far more damaging to the peat than the Walshaw Moor Estate drains.
The position of the infrastructure relative to the watersheds and the contours is critical in analysing its effect on storm runoff. The turbine sites determine the track layout, but the spurs are directly involved in catastrophic storm runoff. The next two diagrams show how much this can vary.

 

Wind farm tracks must go straight up the slope on deep peat (>0.4 m) to reduce the risk of a peat slide. The layout west of Greave Clough would be accessed as three parallel rows T1-T4, T5-T37, T6-(T38) the deleted turbine that was moved to the other side of Walshaw Dean. Christian Egal denies that it was moved, but he is contradicted by the obvious facts, and by the statement of his own consultant Donald Mackay: “T38 was on the blank bit of the peat survey, so we moved it.” T37, (T38), T39 are the three most dangerously sited turbines in CEP. The three parallel access tracks will act as peat drains in normal conditions and in heavy rain as storm drains. Map: WTRG

The watershed spine track across the Wadsworth plateau does not itself greatly increase storm runoff or peat drainage. The spurs to T25, T26 and T28 will drain the prime peat on the plateau at all times, and act as storm drains. Map: WTRG

In a storm the CEP infrastructure has different effects. Infrastructure on a watershed has much less effect than turbines on the edges or slopes and their access tracks. The effect of the infrastructure depends on which catchment it is in.

Greave Clough catchment
In the Greave Clough catchment, the storm runoff is focussed on the sluice and tunnel. All the runoff passes through an active Yorkshire Water asset. When the tunnel is overwhelmed the runoff goes over the dam, down the spillway and direct to Hebden Bridge. If Widdop Reservoir is full, the tunnel runoff will go down the Widdop Dam spillway to Hebden Bridge. The switch at the sluice in a storm greatly increases the speed of runoff from CEP. Since the CEP tracks in the Greave Clough catchment act as storm drains, the infrastructure west of Greave Clough has a massive effect on catastrophic flooding.

The Greave Clough sluice and tunnel. In normal conditions the sluice diverts water over the weir into the tunnel to Widdop Reservoir. In a storm the tunnel is overwhelmed and runoff goes over the dam into the spillway. Photo: Nigel Griffiths
Greave Clough sluice showing the tunnel entrance on the right. Photo: Nigel Griffiths
Huge sums of public money has been spent reducing the drainage west of Greave Clough by blocking the grips dug by the Walshaw Moor Estate. Photo: Ali West
The huge funnel of the Greave Clough catchment. CEP tracks must come straight up the slope and will act as storm drains which will overwhelm the sluice and tunnel. Photo: John Page
Walshaw Dean catchment
The storm runoff all passes through an active Yorkshire Water asset. If the reservoirs are full, the storm runoff goes down the spillways to Hebden Bridge. Some infrastructure is on the Heather Hill watershed. Much of it is on spurs off the watershed, and the spurs will dry the peat and act as storm drains.
The spillway from the Lower Walshaw Dean reservoir (24 February 2024) Photo: Ali West
The meeting of the Greave Clough and Walshaw Dean runoff in the tight valley of Graining Water. (24 February 2024) Photo: Ali West
The meeting of the Walshaw Dean and Greave Clough runoffs (24 February 2024) Photo: Ali West

Crimsworth Dean catchment
This is the largest catchment and has the strongest focus. Most of the CEP infrastructure is near the watersheds. In the valley the water control assets are ruined or defunct.

Abandoned water control assets in Crimsworth Dean. Photo: John Page
Lumb Hole in Crimsworth Dean is a favoured swimming place. Photo: Nick MacKinnon

Effect of CEP on catastrophic flooding
We have seen that some CEP infrastructure will have disproportionate effect on catastrophic flooding compared with tracks and turbines on the watershed. The indicative diagram shows how the risk of catastrophic flooding increases with the size of CEP. All infrastructure increases storm runoff rates, but some has a massive effect.

Indicative cumulative catastrophic flood risk depends on the size of CEP. All turbines add risk, but some add much more risk than others. Diagram: Nick MacKinnon

© WTRG