Massive peat landslide in Donegal, Ireland

Massive peat landslide in Donegal, Ireland

A massive peat landslide occurred near Meenbog Wind Farm in Donegal, Ireland, on Friday afternoon, November 13, 2020. The event made rounds on social media as witnesses posted footage of the slide taking place, showing trees being swept away. Local representatives said they have taken prompt action in contacting relevant agencies regarding the safety of the water in the place as a nearby river has been affected.

The incident was witnessed by passersby Friday afternoon as a number of trees rapidly slid down a slope at Meebog Wind Farm, south of Ballybofey. No injuries were reported, but the event raised concerns for public health and local water supply.

Local representatives visited the site on Sunday, November 15, and found that the landslide caused "substantial damage" to the Mournebeg River and a fish farm.

Councillor Ruarí McHugh said the reps have taken "immediate action in contacting all relevant statutory agencies regarding the emergency [and] the safety of the drinking water in the area." He added, "We will also be raising this directly with the relevant executive ministers."

McHugh noted that he made representations to Donegal County Council, the Loughs Agency, Irish Water and the Environmental Protection Agency (EPA) that an “immediate stop be put on all works at the site until a full investigation is carried out and we know the exact cause of the bog slide."

West Tyrone MP Orfhlaith Begley remarked that the landslide may affect not only the Mournebeg River but also the surrounding rivers.

In an analysis by Dr. Dave Petley of The Landslide Blog, he pointed out that the peat landslide is indeed a large one, "as is so often the case with landslides in peat, the landslide has run out a very long distance, all the way to the major watercourse."

"The upper portion of the Meenbog peat landslide is an extensional zone, almost certainly caused by retrogression (uphill expansion) of the slide after the initial failure.  It is possible that failure started towards the downslope end of this bowl," Dr. Petley further explained.

"It is unlikely to be a coincidence that a ditch crosses the slope at this point.  Downslope from the landslide becomes a channelized flow. The landslide has occurred in an area in which construction is underway for the Meenbog wind farm, a project that has been controversial."

He wrote that peat is a very unusual geotechnical material with very low compressive strength and very low density. It generally has exceptionally high water content and once disturbed, it has a very low shear strength, enabling long-runout landslides to form. Petley noted that special care is necessary to prevent instability in areas of blanket peat coverage.

Footage of the landslide happening made rounds on social media as witnesses captured the actual moment trees were gliding down a slope. The trees involved were reportedly Sitka spruce, and according to the USDA Forest Service, these trees have root systems that are shallow and platelike.

Root grafting often happens between roots of the same tree and adjacent trees. "This explains how trees can be involved in the rafts of the peat slide," Petley wrote.

"The threat of peat slides from wind farms is well-established-- indeed in 2003 a major peat slide was triggered by the construction of a wind farm in Derrybrien." 

According to the Gweebarra Conservation Group, the slip happened because of "wrong trees in the wrong place and a road constructed through the trees and bog to get turbines into the bog," which was polluting waterways on both sides of the border.

In a statement, the group called for a change in the planning system. "Who will clean up this mess? Is it even possible? Three salmon and trout spawning rivers are downstream of this catastrophe. Bogs and Sitka spruce plantations are not suitable locations for wind farms."

Finn Valley Wind Action stated as well that the group "highlighted the risk of this in submissions to Donegal County Council and An Bord Pleanala, but still planning was granted." It added, "The resulting suspended solids have caused the river to become saturated with peat."

Featured image credit: Derg Media

Comments

Tanya Braumiller 15 days ago

". . .but still planning was granted." When will we learn!? Obviously not very soon. And we will suffer for our ignorance.

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