Agri-Environment Division, Agri-Food and Biosciences Institute, 18a Newforge Lane, BT9 5PX, UK.
J Environ Manage. 2012 Jan;93(1):225-34. doi: 10.1016/j.jenvman.2011.09.002. Epub 2011 Oct 13.
The Water Framework Directive (WFD) has initiated a shift towards a targeted approach to implementation through its focus on river basin districts as management units and the natural ecological characteristics of waterbodies. Due to its role in eutrophication, phosphorus (P) has received considerable attention, resulting in a significant body of research, which now forms the evidence base for the programme of measures (POMs) adopted in WFD River Basin Management Plans (RBMP). Targeting POMs at critical sources areas (CSAs) of P could significantly improve environmental efficiency and cost effectiveness of proposed mitigation strategies. This paper summarises the progress made towards targeting mitigation measures at CSAs in Irish catchments. A review of current research highlights that knowledge related to P export at field scale is relatively comprehensive however; the availability of site-specific data and tools limits widespread identification of CSA at this scale. Increasing complexity of hydrological processes at larger scales limits accurate identification of CSA at catchment scale. Implementation of a tiered approach, using catchment scale tools in conjunction with field-by-field surveys could decrease uncertainty and provide a more practical and cost effective method of delineating CSA in a range of catchments. Despite scientific and practical uncertainties, development of a tiered CSA-based approach to assist in the development of supplementary measures would provide a means of developing catchment-specific and cost-effective programmes of measures for diffuse P. The paper presents a conceptual framework for such an approach, which would have particular relevance for the development of supplementary measures in High Status Waterbodies (HSW). The cost and resources necessary for implementation are justified based on HSWs' value as undisturbed reference condition ecosystems.
《水框架指令》（WFD）通过关注流域地区作为管理单元和水体的自然生态特征，推动了向有针对性的实施方法的转变。由于磷（P）在富营养化中的作用，它受到了相当多的关注，产生了大量的研究，这些研究现在构成了 WFD 流域管理计划（RBMP）中采用的措施方案（POMs）的证据基础。将 POMs 针对 P 的关键源区（CSA），可以显著提高拟议缓解策略的环境效率和成本效益。本文总结了爱尔兰流域在将缓解措施针对 CSA 方面取得的进展。对当前研究的回顾表明，与田间尺度 P 输出相关的知识相对全面；然而，由于缺乏特定地点的数据和工具，限制了在该尺度上广泛识别 CSA。在更大的尺度上，水文过程的复杂性增加限制了在集水区尺度上对 CSA 的准确识别。采用分层方法，结合流域尺度工具和逐场调查，可以减少不确定性，并为在一系列集水区中划定 CSA 提供一种更实用和更具成本效益的方法。尽管存在科学和实践上的不确定性，但开发基于 CSA 分层的方法来协助制定补充措施，将为制定针对分散 P 的具体和具有成本效益的措施方案提供一种手段。本文提出了这样一种方法的概念框架，该框架将特别适用于高地位水体（HSW）补充措施的制定。根据 HSW 作为未受干扰的参考条件生态系统的价值， justifies 了实施所需的成本和资源。
