Abstract We investigated the substantive effectiveness of Strategic Environmental Assessment (SEA) of urban planning in Italy and Spain, by looking at the changes made to the original plan as a result of the SEA process. The Italian and Spanish SEA legislations establish an SEA Authority, different from the one that elaborates the plan and the Environmental Report. This authority is in charge of supervising the SEA process and issuing a final statement containing directions and prescriptions on environmental issues to be implemented in the plan as a prerequisite for its approval. After having reviewed a sample of SEA in these two countries, we found that in the great majority of cases the SEA authority required some changes, despite the fact that the plans had undergone an environmental assessment. Results also indicate that the legal arrangements, and in particular the level of independence of the SEA authority (which in Italy and Spain is determined at the regional level), affect the quality and quantity of requested changes. In regions where the SEA Authority is established at a higher level in the planning hierarchy, more substantial changes tended to be required, including more mitigation and compensation measures. On the contrary, in regions where a subsidiary approach is in place, i.e. the SEA authority is established within the same municipality that elaborates the plan, less substantial modifications are more often required. We conclude that in the Spanish and Italian contexts a more effective SEA, in terms of environmental performance of urban plans, is supported by institutional arrangements that provide for an SEA Authority clearly separated and fully independent from the planning Authority.

中文翻译：

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调查城市规划战略环境评估的实质性有效性：来自意大利和西班牙的证据

摘要 我们调查了意大利和西班牙城市规划战略环境评估 (SEA) 的实质性有效性，通过查看 SEA 过程对原始计划所做的更改。意大利和西班牙的 SEA 立法设立了一个 SEA 机构，不同于制定计划和环境报告的机构。该机构负责监督 SEA 过程并发布最终声明，其中包含要在计划中实施的环境问题的指示和规定，作为批准的先决条件。在审查了这两个国家的 SEA 样本后，我们发现在绝大多数情况下，SEA 当局需要进行一些更改，尽管这些计划已经过环境评估。结果还表明，法律安排，尤其是 SEA 当局的独立程度（在意大利和西班牙由区域级别决定），会影响所请求更改的质量和数量。在 SEA 管理局在规划层级中设立更高级别的地区，往往需要进行更多实质性的改变，包括更多的缓解和补偿措施。相反，在采用辅助方法的地区，即在制定计划的同一市内设立 SEA 机构，则更经常需要进行较少实质性的修改。我们得出的结论是，在西班牙和意大利的背景下，在城市规划的环境绩效方面更有效的 SEA，