Fen Management Handbook - Scottish Natural Heritage

A small deep pond or a stand of reeds may be a more acceptable solution than
an engineered sediment trap if adequate space is available. A reedswamp located
where a headwater enters a fen will reduce the velocity and turbulence of water and
provide a matrix in which the silt can become lodged.
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The accumulation of silt in the reedbeds at Blacktoft Sands RSPB
reserve on the Humber Estuary leads to land levels increasing relatively
rapidly. Periodic removal of the accumulated sediments is needed to
maintain the wetland.
7.3 Maintaining open water
The invasion of open-water by emergent aquatic plants, particularly common reed
and bulrush, can occur relatively quickly. Where emergent plants are growing in
standing water and are not too dense (water-fringe fen), it is possible to create
areas of open water through control of water-levels, if this is required for the
conservation of other interests such as invertebrates and birds.
Some brush-cutters and other power tools are suitable for this task, but often
the ground is too soft or the water too deep for them to be operated safely.
Reciprocating-blade mowers or scythes can work effectively provided reed is not
too dense and the area to be cut is relatively limited. Most commercial reed and
sedge cutters use pedestrian mowers of various sorts. The Broads Reed & Sedge
Cutters Association (BRASCA) have a wealth of practical experience in cutting fen
vegetation (see Section 6: Fen Vegetation Management and Broads Reed &
Sedge Cutters Association).
Maintaining open water at Brackagh Bog
At Brackagh Bog in Northern Ireland, which is an extensive area of fen developed from
cut-over bog, pools are mechanically excavated on a cyclical basis to simulate abandoned
peat cutting practices. The maintenance of open water at Brackagh Bog is essential to
maintain the diversity of fen communities and the rich invertebrate fauna for which the
area is renowned.
Rectangular pools freshly excavated at Brackagh
Bog in Northern Ireland to lower the level of the fen
re-establishing the successional process from open
water to species rich fen (B. Hamill).
The newly created pools are rapidly colonised by
aquatic and fen plants from nearby seed sources and
plant rhizomes. (B.Hamill)
Over approximately five years, the pools become
completely infilled, creating species-rich fen
communities with a diverse fen flora. After a further
period of time, the mechanical excavation of open
pools in this area will begin again (B. Hamill).