Laboratory of Hydrology and Water Resources Management, Department of Water Resources and Environmental Engineering, National Technical University of Athens, 5 Iroon Politechniou street, 15780 Zografou, Athens, Greece.
J Environ Manage. 2011 Oct;92(10):2823-35. doi: 10.1016/j.jenvman.2011.06.035. Epub 2011 Jul 13.
Two kinds of agricultural Best Management Practices (BMPs) were examined with respect to cost-effectiveness (CE) in reducing sediment, nitrates-nitrogen (NO(3)-N) and total phosphorus (TP) losses to surface waters of the Arachtos catchment in Western Greece. The establishment of filter strips at the edge of fields and a non-structural measure, namely fertilization reduction in alfalfa, combined with contour farming and zero-tillage in corn and reduction of animal numbers in pastureland, were evaluated. The Soil and Water Assessment Tool (SWAT) model was used as the non-point-source (NPS) estimator, while a simple economic component was developed estimating BMP implementation cost as the mean annual expenses needed to undertake and operate the practice for a 5-year period. After each BMP implementation, the ratio of their CE in reducing pollution was calculated for each Hydrologic Response Unit (HRU) separately, for each agricultural land use type entirely and for the whole catchment. The results at the HRU scale are presented comprehensively on a map, demonstrating the spatial differentiation of CE ratios across the catchment that enhances the identification of locations where each BMP is most advisable for implementation. Based on the analysis, a catchment management solution of affordable total cost would include the expensive measure of filter strips in corn and only in a small number of pastureland fields, in combination with the profitable measure of reducing fertilization to alfalfa fields. When examined for its impact on river loads at the outlet, the latter measure led to a 20 tn or 8% annual decrease of TP from the baseline with savings of 15€/kg of pollutant reduction. Filter strips in corn fields reduced annual sediments by 66 Ktn or 5%, NO(3)-N by 71 tn or 9.5% and TP by 27 tn or 10%, with an additional cost of 3.1 €/tn, 3.3 €/kg and 8.1 €/kg of each pollutant respectively. The study concludes that considerable reductions of several pollutant types at the same time can be achieved, even at low total cost, by combining targeted BMP implementation strategies only in small parts of the catchment, also enabling policy makers to take local socio-economic constraints into consideration. The methodology and the results presented aim to facilitate decision making for a cost-effective management of diffuse pollution by enabling modelers and researchers to make rapid and reliable BMP cost estimations and thus being able to calculate their CE at the local level in order to identify the most suitable areas for their implementation.
两种农业最佳管理措施（BMPs）在减少希腊西部阿拉克托斯流域地表水中的泥沙、硝酸盐氮（NO(3)-N）和总磷（TP）损失方面的成本效益（CE）进行了研究。评估了在田间边缘建立过滤带和一种非结构性措施，即减少紫花苜蓿施肥，结合玉米等高线耕作和免耕以及减少牧草地动物数量。土壤和水评估工具（SWAT）模型被用作非点源（NPS）估算器，同时开发了一个简单的经济组件，估算实施 BMP 的成本，即实施和运营该措施 5 年所需的平均年度费用。在实施每个 BMP 之后，分别为每个水文响应单元（HRU）、每个农业土地利用类型和整个流域计算其减少污染的 CE 比值。在流域尺度上的结果以地图的形式全面呈现，展示了整个流域内 CE 比值的空间差异，有助于识别每个 BMP 最适合实施的位置。基于分析，一个负担得起的总成本的流域管理解决方案将包括在玉米中实施昂贵的过滤带措施，而仅在少数牧草地中实施，同时结合减少紫花苜蓿施肥的有利措施。当考察其对出口处河流水负荷的影响时，后一种措施导致 TP 每年减少 20 吨或 8%，污染物减少 15 欧元/公斤。玉米田中的过滤带减少了每年 66 千吨或 5%的泥沙、71 吨或 9.5%的硝酸盐氮和 27 吨或 10%的总磷，分别增加了 3.1 欧元/吨、3.3 欧元/公斤和 8.1 欧元/公斤的成本。研究得出结论，即使总成本较低，通过仅在流域的一小部分地区实施有针对性的 BMP 实施策略，也可以同时实现多种污染物类型的大量减少，同时使决策者能够考虑当地的社会经济限制。所提出的方法和结果旨在通过使建模者和研究人员能够快速可靠地估算 BMP 成本，从而能够在当地计算其 CE，从而确定最适合实施的区域，为具有成本效益的分散污染管理提供决策便利。
