Methods to predict the agricultural contribution to catchment nitrate loads: designation of nitrate vulnerable zones in Northern Ireland
Methods to predict the agricultural contribution to catchment nitrate loads: designation of nitrate vulnerable zones in Northern Ireland
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DOI：
10.1016/j.jhydrol.2004.07.037
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发表时间：
2005-03
影响因子：
6.4
通讯作者：
C. Jordan;R. V. Smith
中科院分区：
文献类型：
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作者：
C. Jordan;R. V. Smith
欧洲法院裁定，《硝酸盐指令》规定，欧盟成员国有义务将富营养化水域的集水区指定为硝酸盐脆弱区(NVZ)，在这些地区，农业是硝酸盐污染的重要来源。最近，欧盟委员会表示，当可以证明农业对这些水域的硝酸盐总负荷的贡献超过20%时，就应该指定NVZ。已经使用了两种方法来确定北爱尔兰的集水区，在那里满足了这一条件。第一种方法使用地理信息系统根据牲畜数据预测农田到地表水的硝酸盐扩散损失，并使用淋失系数在所有主要集水区之间分配年度化肥使用量和粪便。第二种方法是基于出口系数建模。在第一种方法中，考虑到反硝化损失，以及从大气和生活污水输入到地表水的氮，以将总硝酸盐负荷分配到每条主要河流，从而确定集水区是否满足20%的被指定为NVZ的标准。这两种方法都根据现有的河流监测数据进行了验证，并提供了一定程度的预测，为初步筛选将被指定为目标的集水区提供了足够的信息。除了包括贝尔法斯特市在内的拉甘河流域，农业对硝酸盐负荷的贡献仅为8.5%，其余流域的农业贡献从33%到86%不等。这意味着，如果后者的地表水存在富营养化，北爱尔兰的大部分地区应该被指定为NVZ。
The European Court of Justice has ruled that the Nitrates Directive places an obligation on EU member states to designate the catchments of eutrophic waters as Nitrate Vulnerable Zones (NVZs), where agriculture is a significant source of nitrate pollution. Recently, the European Commission has indicated that NVZs should be designated when agriculture can be shown to contribute more than 20% of the overall nitrate loading to those waters. Two methods have been used to identify catchments in Northern Ireland, where this condition is met. The first method employs a GIS to predict diffuse losses of nitrate from agricultural land to surface waters based on livestock data and a leaching factor to apportion the annual fertiliser usage and manure between all major catchments. The second method is based on export coefficient modelling. In the first method, allowances for denitrification losses, together with inputs of N from the atmosphere and domestic sewage to surface waters, were made to apportion the total nitrate load to each major river and thus determine if the catchment satisfied the 20% criterion to be designated as a NVZ. Both methods were validated against existing river monitoring data and offered a level of prediction that provides adequate information for a preliminary screening of those catchments to be targeted for designation. Apart from the River Lagan catchment, which includes the city of Belfast and where agriculture only contributed about 8.5% to the nitrate load, the agricultural contribution in the remaining catchments ranged from 33 to 86%. This implies that, if eutrophication is present in the latter surface waters, most of Northern Ireland should be designated a NVZ.