River restoration: does better monitoring mean fuzzier conclusions?

Posted on October 15, 2015


Although stream restoration activities are commonplace, the assessment of project success has been patchy, and in many cases little or no time has been allowed for the comparison of sites before and after restoration. In a study of restoration evaluation, French researchers collected data on 44 stream restoration projects, each from a different river, by interviewing scientists and practitioners. The most common project activities were habitat or channel restoration, which often involved adding instream structures or remodeling or redirecting the stream. The evaluation process was described in terms of the monitoring framework, the monitoring duration, the number of biophysical indicators used and the total number of surveys. Cluster analysis of these variables was used to classify projects according to evaluation quality, ranging from basic (few surveys, few biophysical indicators) to ambitious (long monitoring period, at least four biophysical indicators). When these evaluation classes were related to the perceived success of the stream restoration activities it was found that projects with poor assessment strategies tended to be seen as more successful: the better the assessment strategy, the more ambiguous the conclusions that were reached. This result indicated that in most cases, project evaluation wasn’t scientifically based. Other data showed that the indicators chosen to measure restoration success varied depending on the political authority in charge of the evaluation. Because monitoring is often used as a scientific cover for a more subjective assessment, the question of values is central to restoration, and it’s important to decide whether evaluation is being made to measure the impact of public policy, to justify restoration to local communities, or to improve scientific knowledge.

Reference: Morandi, B. et al. 2014. How is success or failure in river restoration projects evaluated? Feedback from French restoration projects. Journal of Environmental Management 137, 178-188.

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