Stream restoration efforts have increased, but the success rate is still rather low. The underlying reasons for these unsuccessful restoration efforts remain inconclusive and need urgent clarification. Therefore, the aim of the present study was to evaluate over 40 years of stream restoration to fuel future perspectives. To this purpose we evaluated the influence of policy goals on stream restoration efforts, biophysical restoration objectives, restoration measures applied including the scale of application and monitoring efforts. Information was obtained from five stream restoration surveys that were held among the regional water authorities in the Netherlands over the last 40 years and from an analysis of the international scientific publications on stream restoration spanning the same time period. Our study showed that there was a considerable increase in stream restoration efforts, especially motivated by environmental legislation. However, proper monitoring of the effectiveness of the measures was often lacking. Furthermore, a mismatch between restoration goals and restoration measures was observed. Measures are still mainly focused on hydromorphological techniques, while biological goals remain underexposed and therefore need to be better targeted. Moreover, restoration practices occur mainly on small scales, despite the widely recognized relevance of tackling multiple stressors acting over large scales for stream ecosystem recovery. In order to increase the success rate of restoration projects, it is recommended to improve the design of the accompanying monitoring programmes, allowing to evaluate, over longer time periods, if the measures taken led to the desired results. Secondly, we advise to diagnose the dominant stressors and plan restoration measures at the appropriate scale of these stressors, generally the catchment scale.

中文翻译：

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四十年来的低地河流恢复：经验教训？

溪流修复工作有所增加，但成功率仍然很低。这些未成功进行恢复工作的根本原因尚无定论，需要紧急澄清。因此，本研究的目的是评估40多年的河道修复，以推动未来的发展。为此，我们评估了政策目标对河流恢复工作，生物物理恢复目标，所采用的恢复措施（包括应用规模和监测工作）的影响。信息是从过去40年中在荷兰的地区水务部门之间进行的五次河流恢复调查中获得的，以及对同一时期有关河流恢复的国际科学出版物的分析得出的。我们的研究表明，溪流修复工作显着增加，尤其是在环境立法的推动下。但是，经常缺乏对措施有效性的适当监测。此外，还发现了恢复目标和恢复措施之间的不匹配。措施仍然主要集中在水形态学技术上，而生物学目标仍然曝光不足，因此需要更好地针对性。此外，尽管为解决河流生态系统恢复问题而广泛应对应对多种压力源的问题广为人知，但恢复实践主要发生在小范围内。为了提高修复项目的成功率，建议改进随附的监控程序的设计，以便在更长的时间内进行评估，如果采取的措施导致了预期的结果。其次，我们建议诊断主要的压力源，并在这些压力源的适当规模（通常是流域规模）上计划恢复措施。