Fen Management Handbook - Scottish Natural Heritage

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Experiences of using different boardwalk materials
– The National Trust started using hardwood 20 years ago at Wicken
Fen but found it deteriorated rapidly and is now replacing it with
recycled plastic.
– The Norfolk Wildlife Trust found that tanalised timber boardwalk at
Hickling had a life of 12-15 years.
– At Strumpshaw Fen the RSPB found chestnut lasted for about 15
years though the wire netting nailed on it as a non-slip surface lasted
for only 5.
– The main problems associated with boardwalks are risk of floating
away during flooding, and sinking into peat. At Wicken Fen this
has been overcome by anchoring the boardwalk into soil 3 m or so
below the peat surface. At Hickling the boardwalk rests on 4 m long
75x75 mm stakes, and at Ranworth the boardwalk sits on jointed,
tanalised timber stilts above 6.5 m of quaking mire, incorporating a
recycled plastic section for the top 0.5 m for durability.
– Past attempts to float boardwalk on top of peat using sleepers or
battens have been abandoned at Wicken Fen, Hickling Broad and
Ranworth because of subsidence and rippling as the vegetation
died and the peat shrank. However larger 100 mm posts anchored
in the peat every 2 m along the path, with cross battens between the
posts to provide additional buoyancy, have been successful at some
sites.
The 500 m long boardwalk to Ranworth visitor centre is designed for
wheelchair access. It is 1.2 m wide, with a kick rail on each side to
prevent wheels falling off, with passing places every 100 m or so.
A transboundary boardwalk
across fen, built for the
first ecotourists to visit
the region, crosses from
Belarus into Russia
(S.Street)