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Flanders Moss NNR a raised bog. ŠLorne Gill/SNH. For information on reproduction rights contact the Scottish Natural Heritage Image Library on Tel. 01738 444177 or

Restoring the raised bog at Flanders Moss NNR

Our whole focus for management at Flanders Moss NNR has been to reverse the trends of drying out caused by drainage ditches, peat removal and the spread of trees.  Our ultimate aim is to restore the water table over the peat body to a stable position as close to the surface as possible.

Over the years we have tried a number of techniques to help restore the water table including ditch damming, lagg fen restoration, tree and scrub management and stock grazing.

Ditch damming

Damming techniques have evolved at Flanders over the last 15 years.  The first dams we used were oak and elm boards.  These dams took a lot of labour to put in and many failed.  Nowadays, we use sheet piling made from recycled plastic which is more flexible, a lighter material and longer lasting.

Over the last 10 years, we have dammed approximately 35 kilometres of ditches, using about 1000 dams.

Restoring lagg fen

Lagg fen is a natural feature of a raised bog.  It is created around the edges of the peat domes where seepage from the peat body meets mineral soils.  At Flanders the lagg fen is drained by a large peripheral ditch which accelerates drying out.

The ditch also prevents water seeping out onto neighbouring farm land so, recreating this habitat requires a different approach to just blocking the ditch.  By using a sluice and bund to keep the water level high around the edge of the bog we have managed to create lagg fen habitat and ensure there is no flood damage to neighbouring land.

Tree and scrub management

Trees and scrub have spread over a large part of the bog. The trees also cause the bog to dry out but with a constant seed source off the Reserve, it is very difficult (if not impossible!) to have a completely tree-free bog. Our efforts have therefore concentrated on removing the trees and scrub that cause most damage. In 1997-98 we removed 40 hectares of conifer plantation. We have also removed 8 hectares of rhododendron and we are continually removing young trees and scrub from different parts of the Reserve.


Sheep and cattle play an important role in keeping young trees and scrub at bay.  We have found that grazing the bog with sheep for two periods of 4 weeks each during summer does help to reduce scrub encroachment.

Unfortunately though, the number of sheep required to eliminate the scrub altogether would cause damage to the bog surface.  There is a fine balance to reach.


We monitor the changes in the height of the water table using instruments called Walrags.  Our monitoring has shown us that there has been a significant increase in the height of the water table since the conifer plantation was removed and many of the ditches blocked.  In some places the water table is nearly at the surface.

We can also see changes on the the ground.  Sphagnum (bog moss), which is the peat forming plant, is growing in the ditches and over areas which were previously too dry for it to grow.

Peat bog restoration video

As part of a Sharing Good Practice event on Restoration and Decommissioning of Windfarms, SNH created a 'virtual' site visit, featuring Flanders Moss NNR, to highlight good practice techniques and management options for peat bog restoration. 

Last updated on Monday 10th December 2012 at 12:19 PM. Click here to comment on this page