A RECENT TRANSFORMATION FROM POOR TO RICH FEN CAUSED BY ARTIFICIAL GROUNDWATER RECHARGE

Situated in the Campine region of Belgium, which is known for its thick sandy deposits and acid soils, the Buitengoor is a small headwater valley fen, containing many rich fen indicator species that are typical of neutral to alkaline soils. A hydrochemical survey of the surroundings of the fen pointed to an irrigation canal as a possible source of alkalinity for the fen. Just upstream of the fen, the alkaline canal water recharges the ground water. A piezometer transect from the canal to the fen illustrated the recharge pathway and the fate of alkalinity, cations and nutrients in the aquifer. Alkalinity and base cations are supplied to the fen while nutrients disappear out of solution. Although the normal hydroseral development of this fen would have been directed towards bog, the canal water caused an opposite development towards rich fen. This result illustrates the potential for groundwater flow systems to reverse peatland development in a short period of time (the canals were built in the last century). The potential for restoration of the rich fen habitat is discussed.