The contamination of European surface and groundwaters by nitrate is more prevalent than anywhere else in the world, and is becoming one of the major factors determining the readily-usable quantity of water resources available within Europe. The control of water pollution, in particular nitrate, has become a major focus of recent European Community Directives, in which the emphasis is prevention rather than cure. Since there is an urgent requirement for action to control the nitrate concentration of freshwaters, there is a need to utilise existing knowledge in the development of management strategies designed to reduce the risk of such pollution impacts upon the environment. The ability of the riparian zone to act as a nitrogen sink has been demonstrated under temperate climates. This programme aims to delimit the range of conditions (climate, geomorphology and farming system) under which riparian zones offer effective protection to freshwater ecosystems. The main objective of the NICOLAS programme is to evaluate the natural performance of riparian zones to sustainably buffer water-borne fluxes of diffuse nitrogen pollution from agriculture to aquatic environments and devise a riparian ecosystem management model (REMM) to predict the nitrogen fluxes through these systems applicable to a range of farming and climatic conditions.
The NICOLAS programme is structured around four objectives:
The first objective seeks to evaluate the nitrogen retention and transformation processes of morphologically similar riparian structures within representative agricultural drainage basins of Europe (experimental drainage basins from France, Great Britain, The Netgerlands, Poland, Romania, Spain and Switzerland.
The nitrogen budget obtained from each of the seven study sites will be used to calibrate a European-based riparian ecosystem management model (REMM).
REMM will enable us to evaluate the consequences of different landscape change scenarios on the buffering capacities of riparian zones either by predicting the optimum riparian structure in a given area, or by indicating the best combination of land use and riparian structure.
Finally, the NICOLAS programme will follow a series of analytical steps to identify alternative buffering structures within the study catchments. Their nitrogen retention capacity will be assessed and compared to those measured for the riparian zones. This will help identify the landscape structures best suited mitigating diffuse nitrogen pollution.