Rewetting of the blanket peat of Dartmoor

Those who attended our Debate on What Future for Dartmoor’s Water Resources? last September will recall that Simon Bates of Natural England mentioned a ‘pilot’ project on the Rattlebrook (an ‘instant success’) at SX 561870 for rewetting the blanket bog by building timber dams in old peat-cutting channels.

This met with some scepticism, especially from your Chairman (see p.33 of Newsletter 33, October 2008).

Since then, Natural England, Dartmoor National Park Authority and the Duchy of Cornwall have pressed ahead with a much bigger scheme on the newly named ‘Blackabrook Down’, a substantial hill N of Black Dunghill, between the rivers Walkham and Cowsic, at SX 583782.

Dams on Blackabrook Down, Jan 09
Dams on Blackabrook Down, Jan 09

Here some 200 timber and turf dams have been set in old peat-cutting drainage channels and another 400 dams are proposed. An equivalent scale of operation is planned for Flat Tor Pan (between the West and East Dart rivers) at SX 612811, and on Winney’s Down (SX 625820), with a smaller area on Hangingstone Hill (SX 617857). Astonishingly, the Blackabrook work has been done without any consultation with commoners who are charged to manage the grazing under the Dartmoor Commons Act 1985. Hill farmers have questioned the legality of the work, as they see their ‘lears’ (traditional grazing areas) have been disrupted, as well as access routes for stock. They are also concerned that calves and sheep might fall into the new ponds. Walking will undoubtedly become more difficult too. Tracks are being created by the machinery being used.

Initially trumpeted as ‘carbon storage’, the latest message from DNPA is that the project is all about ‘biodiversity’ with the aim to

  • Enhance condition of the blanket bog community
  • Reduce run-off rates in high rainfall periods
  • Retain flows in low rainfall periods
  • Improve habitat conditions for Atlantic salmon
  • Enhance breeding habitat suitability for wading birds
  • Enhance the capacity of the bog to store carbon

The words used and the aims sound plausible but The Dartmoor Society has every reason to be concerned about this work – in the 1990s the same bodies assured us that Dartmoor was overgrazed and needed a 50% reduction in grazing animals. The result has been a vigorous growth in vegetation (especially gorse and coarse grass) which is causing very serious problems for hill farmers, walkers and those who wish to study and explore archaeological features.

The present claim by Natural England that the blanket bog (12,000 ha) of Dartmoor needs ‘restoration’ is hardly proven – criteria borrowed from northern English moors have little relevance to Dartmoor where plant species and conditions are different. Natural England also seems remarkably antagonistic towards traditional swaling (burning of moorland vegetation.

A likely prehistoric barrow cemetery on Blackabrook Down does not seem to have been recognised and the old peat workings, which are archaeological features in their own right, are being compromised by the dams. There is no significant erosion of peat here or elsewhere on Dartmoor (except where turves have been dug to make dams!). The project seems more driven by the availability of funds (several hundred thousand pounds of public money to be spent within a short timescale), and fashionable vocabulary, rather than any rigorous analysis of the situation.

However, some good things are riding on the back of the project – Dr Ralph Fyfe of the University of Plymouth (who gave our Research Lecture in 2007) is doing some very important work measuring the depth of peat and dating its formation, but no preliminary work seems to have been done on the way in which peat retains water. A handful of ‘dipwells’ are being introduced to monitor changes in the water table.

Perhaps most disconcerting is that the external experts seem to have little understanding of the historic management of Dartmoor nor, more specifically, understanding of the ancient peat industry of the moor, and yet they are hell-bent on interference.

The project seems to have gone well beyond a ‘pilot’ phase without rigorous debate, despite the project brief stating that “Restoration will be planned and undertaken with full consultation of all relevant organisations and individuals”. The project unfortunately reflects the inappropriate dominance of Natural England without a properly balanced approach, which should take into account the long cultural history of Dartmoor.

Hill farmers are facing enormous difficulties thanks to the flawed decisions of the 1990s. This project will do nothing to reassure them, though no doubt they will be offered money as compensation which, attractive to some, is insulting and demeaning to others, and will still not resolve grazing issues.

Tom Greeves