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波罗的海正在经受富营养化的危害,人们正在设法降低营养物质负荷。本文以瑞典南部(145 000km~2)氮素迁移为核心提出了模型方法(HBV-N),该模型已经用于国家的决策过程,以获得最佳管理措施。本文计算了1985～1994年间淡水系统的氮素淋溶量和持留量,向海洋的净迁移量,以及源的比例分配。输入数据是采用GIS处理的,还包括来自SOIL-N和MATCH的结果。对3725个子流域进行了逐日模拟,并对722个地点就测定时间系列进行了标定。扩散源污染通常在进入河网之前有10%～25%被持留。湖泊通常能减少湖区30～40kg/hm~2·a的氮素迁移量。平均而言,年毛负荷量的45%在迁移过程中被减少了,但时间和空间变化很大。进入海洋的有75 000t N/a。
The Baltic Sea is undergoing eutrophication and people are trying to reduce the load of nutrients. In this paper, we propose a model approach (HBV-N) based on nitrogen migration in southern Sweden (145 000 km 2). This model has been used in national decision-making processes to obtain the best management practices. This paper calculates the amount of nitrogen leaching and holding, the net migration to the ocean, and the source distribution of freshwater systems from 1985 to 1994. Input data is processed using GIS and includes results from SOIL-N and MATCH. Day-to-day simulations of 3725 sub-basins were carried out and the series of time determinations were calibrated for 722 locations. Pollution from diffuse sources is usually retained between 10% and 25% before entering the river network. Lakes generally reduce the amount of nitrogen transported from 30 to 40 kg / hm 2 · a in the lake. On average, 45% of annual gross load is reduced during the migration, but time and space vary widely. There are 75 000t N / a into the ocean.