Assessment of risks to drinking water provision in Glitrevann from forest fertilization and harvesting

Forest fertilization is planned in the Glitre catchment, an important drinking water source for the Drammen region. In this report, we explore whether fertilization is likely to put drinking water provision in the catchment at risk over the short term, as well as longer-term risk associated with fertilization and forest harvesting. Overall, we find there is little risk of forest fertilization reducing the water quality in Glitrevann, provided the forest management plans provided by Statskog are followed, together with fertilization and harvesting best management practices (as outlined in the Norwegian PEFC Forest Standard). We recommend routine stream monitoring be carried out during and for several years after harvesting to screen for potential effects.