The Source to Tap INTERREG VA funded project is working on a pilot forest-to-peatland restoration project at Tullychurry in Co. Fermanagh which they hope will restore approx. 32ha of the previous commercial conifer plantation to a functioning bog.
The pilot is trialling a technique called cell bunding and comparing the recovery of the water table in the bog to other areas where rather than building cell bunds only the drains are blocked. The restoration will demonstrate multiple benefits for nature, carbon capture and water quality in the future.
Source to Tap is a €4.9m project to protect and improve our rivers and lakes in the Erne and Derg cross border catchments.
The project is funded and supported by the European Union’s INTERREG VA Programme, with match funding from the Department of Agriculture, Environment and Rural Affairs (DAERA) in Northern Ireland and the Department of Housing, Local Government and Heritage (DHLGH) in Ireland and managed by the Special EU Programmes Body, (SEUPB).
NI Water is the lead partner and the Source to Tap project unites water companies from both sides of the Ireland-Northern Ireland border, with Irish Water a partner as well as bringing together the Agri-Food Biosciences Institute, Ulster University, The Rivers Trust and East Border Region.
Initial results from the pilot will be made available in a technical report in 2021.
More information here: Peat – Source to Tap
Details
On our test site at Tullychurry, where different peat restoration methods have been trialled, the first step was to cut down the plantation forest that covered the land. It was also essential to flatten out the soil which had been plowed in a ridge and furrow pattern, as the greater surface area increases moisture loss. The team could then focus their efforts on bringing water levels back up by preventing it from escaping. Two methods were trialled: cell bunding and drain blocking.
Sphagnum mosses play a vital role in the creation of peat bogs: by storing water in their spongy forms, they prevent the decay of dead plant material and eventually form peat. Encouraging its recolonisation is therefore an important part of the restoration process and after the initial work raising the water table, some of the trial land was sprayed with sphagnum seed to see whether this speeded up the process.
Deep trench or cell bunding is the construction of watertight cells made from low peat walls, constructed at a 90 degree angle to the slope with a bund roughly every 30 cm fall in height.
“Finger bunds” are then constructed at intervals in line with the slope, joining the parallel bunds to prevent lateral erosion and wave action. By creating these watertight cells it allows the water table to rise, encouraging the growth of sphagnum moss.
Drain blocking is a popular method of peatland restoration. Peat dams were used to block each drain at 12 m intervals or every 30 cm drop in ground level. Dams were constructed using saturated peat from a borrow pit adjacent to the dam location and covered with vegetation and brash to prevent wind and rain erosion.
The control area was used to compare methods of current forestry best practice, observed on another restoration site, with other restoration methods. In this area, drains were blocked with peat dams only where they exited the area.
Each of the three restoration areas were monitored using piezometers. These are shallow groundwater wells which are sunk around 1.5-2 m into the ground and were used to monitor water table recovery post restoration. A fourth area, of intact blanket bog was also monitored as a comparison.