Isn't Dartmoor wet enough already? |
As I walked along I pondered the term I’d just heard, “they are re-wetting over there”. What on earth was that? A local version of hair of the dog? A second excuse to celebrate a new born’s arrival? I thought I was getting quite good at Dartmoor vernacular. Although it’s taken years I can just about deal with sentences like “I was at the Ringleshutes Mine Gert near the adit, in all that pixie wool, at first I thought it was clitter but it turned out to be a buddle”. Re-wetting was a new one on me.
Searching around, and after a delightful misunderstanding led me to discover thermopedia (who are also interested in re-wetting, just not the same kind) I found some interesting notes.
In the context of Dartmoor, moorland and fen re-wetting appears to be a term for restoring natural water flow by blocking off human introduced drainage and erosion channels. Moorlands have been drained on a literally industrial scale for all sorts of reasons from farming to mining to water supply. Peat has been removed at a ferocious rate for fuel and Naptha and occasionally bombed by the military. Re-wetting aims to improve biodiversity and carbon absorption, and makes a difference to both in a relatively short time, primarily through new growth, initially it’s not restoring lost peat, its just better than drained moor. It appears that it will take decades to restore lost peatland, hardy surprising given the 10,000 or so years it has been accumulating, and only around 1% of Dartmoor's healthy peat land remains.
Re-wetting also helps reduce flooding by reducing run off, keeping water for longer on the moor and in flood plains. This is also good for water supplies, according to the South West Peatland Project 45% of South West Water’s daily water supply falls on the moors.
The methods of re-wetting are simple, even if getting materials to where they are needed is not. Essentially ‘leaky dams’ are created with natural materials like peat, heather and willow branches. Sturdier dams are constructed from stone or timber. If you do give a dam about dams the Headwaters Natural Flood Management project bulletin has details of experiments and evaluations and there are some good pictures of re-wetting on Holne Moor on Adrian Colston’s informative blog.
Oh, and if you're interested in the meaning of the sentence in the opening paragraph, which is of course entirely made up, it roughly translates to " I was at the big gully at Ringleshutes Mine, near the way in, where there's all that fluffy cotton grass, at first I thought it was random rocks but it turned out be the site of a pit for separating minerals."