NITROGEN-RETENTION IN RIVER CORRIDORS - EUROPEAN PERSPECTIVE

The problem of nitrogen pollution in European surface- and groundwater s has become a focus of recent European and Scandinavian directives, w ith legislation calling for a 50% reduction of N losses by the years 1 995 and 2000, respectively. This paper provides a conceptual framework upon which management strategies to reduce losses of diffuse nitrogen pollution to surface waters may be based. The control of nitrogen pol lution may take place through an increase in the complexity of the lan dscape, not throughout the catchment area, but rather in specific zone s, the river corridor in particular. Within river corridors, riparian areas have been recognized globally for their value as nutrient remova l ''buffer systems''. Studies have identified vegetation uptake and mi crobial denitrification as the primary mechanisms responsible for N re moval in these systems. For these processes to function optimally on a n annual basis, both vegetation and water regime must be managed. The establishment and management of riparian buffer zones in suitable plac es within river corridors, will provide a stable and sustainable water -protection function. This will complement future nitrogen input contr ol strategies, needed for both the long-term protection of groundwater and surface waters in Europe as a whole, and for the proposed 50% red uction in nitrogen loading to the Baltic and North Sea coastal waters by the turn of the century.