Fen Management Handbook - Scottish Natural Heritage

9.7.4 Water quality
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An example of a soil map
for an RSPB site
The quality of water entering the proposed site is nearly as important as water
quantity, and will to a large extent determine the type of fen that will establish. The
pH and concentrations of the major plant nutrients (nitrate, ammonium, phosphate,
potassium and calcium) must all be taken into account.
In some areas nitrate concentrations in groundwater have increased significantly
and have resulted in the eutrophication of wetlands at the base of slopes or in valley
bottoms. River water quality will be affected by upstream land-use and discharges
(see Section 4: Understanding Fen Nutrients). Further information and guidelines
on how to undertake or commission water quality testing are outlined in Section 10:
Monitoring to Inform Fen Management.
9.7.5 Substrate nutrient levels
The texture of the substrate is partly responsible for its fertility, but the quantity of
nutrients within the substrate will significantly affect what type of fen vegetation
can or will establish. Sands and gravels tend to be relatively nutrient poor and are