Historic Migneint upland bog ditches filled in
Miles of ditches dug on a peat bog over the last two centuries are being filled in with the aim of storing carbon and reducing flooding in the valley below.
The £250,000 restoration work on the Migneint upland bog between Ffestiniog and Llanrwst on the Gwynedd-Conwy border is funded by the National Trust.
A 400-mile network of ditches crisscrossing the area is to be closed.
The Migneint is Wales' second largest of moorland and is also a European-designated special conservation area.
The ditches have been used for drying out the bog for sheep pasture and grouse shooting.
But now they are being filled in by mechanical diggers 1,000ft (300m) up, in an attempt to keep the wet and sponge-like nature of the Migneint.
The area forms around 8,000 acres (3,200 hectares) of a trust estate near Ysbyty Ifan, Conwy.
Several agencies have been assessing the benefits of retaining a high water table in the peat. Among them is the Bangor-based Centre for Ecology and Hydrology.
Dr Ed Rowe is part of team interested in keeping carbon dioxide, a known greenhouse gas capable of causing climate change, locked in the Migneint soil.
He said: "The thing about Welsh bogs is that they have a great amount of carbon stored in them, something like 70 times the amount that cars and vehicles in Wales use in a year.
"So it's very important we keep that carbon in place. And with draining them, you are more likely to lose that carbon."
It is hoped that filling in the ditches will have the dual benefit of alleviating annual flooding in the Conwy Valley.
The National Trust's Trystan Edwards said: "In terms of agriculture, the density of sheep up here has gone down tremendously. The labour required to manage these areas is just not there anymore.
"There's a benefit for farmers in working with biodiversity and with the environment.
"The ditches are extremely effective at carrying water.
"We can't put any calculations or put an objective view on it but commonsense tells us that the Migneint is probably going to be an extremely effective water store, and allow water maybe to percolate a little bit slower down the river.
"We're hoping that it will have a beneficial impact further on down."