Riverine nutrient loads are among the major causes of eutrophication of the Baltic Sea. This study applied the Soil & Water Assessment Tool (SWAT) in three catchments flowing to the Baltic Sea, namely Vantaanjoki (Finland), Fyrisån (Sweden), and Słupia (Poland), to simulate the effectiveness of nutrient control measures included in the EU’s Water Framework Directive River Basin Management Plans (RBMPs). Moreover, we identified similar, coastal, middle-sized catchments to which conclusions from this study could be applicable. The first modelling scenario based on extrapolation of the existing trends affected the modelled nutrient loads by less than 5%. In the second scenario, measures included in RBMPs showed variable effectiveness, ranging from negligible for Słupia to 28% total P load reduction in Vantaanjoki. Adding spatially targeted measures to RBMPs (third scenario) would considerably improve their effectiveness in all three catchments for both total N and P, suggesting a need to adopt targeting more widely in the Baltic Sea countries.

河流养分负荷是波罗的海富营养化的主要原因之一。本研究在流向波罗的海的三个流域，即 Vantaanjoki（芬兰）、Fyrisån（瑞典）和 Słupia（波兰）中应用了土壤和水评估工具 (SWAT)，以模拟包含在欧盟水框架指令流域管理计划 (RBMP)。此外，我们确定了类似的、沿海的、中等规模的流域，本研究的结论可能适用于这些流域。第一个基于现有趋势外推的建模方案对建模养分负荷的影响不到 5%。在第二种情况下，RBMP 中包含的措施显示出不同的有效性，从 Słupia 的可以忽略不计到 Vantaanjoki 的 28% 的总磷负荷减少。