Tool to assess the effectiveness of restoring physical conditions in riparian wetlands

The success of river restoration is a controversy subject depending on chosen reference conditions and stakeholder perspective. Therefore, the tool to assess the effectiveness of restoring physical conditions in riparian wetlands aims to be a comprehensible piece of evidence to policy-makers. The assessment is based on three hypotheses: (i) the restoration should have standard-based results; (ii) the restoration should respect principle-based results; (iii) the nature is more valuable without human pressures. Therefore, the multi-criteria methodology includes three categories of indicators: (i) to detect results compared to pre-restoration conditions as well as to historical conditions; (ii) to estimate the functionality of physical conditions compared to expert opinion; (iii) to analyze the naturalness of a river site. Each indicator is given a score compared to hypothetically successful effects of the restoration based on an earth scientist approach. The overall score allows to classify the effectiveness of river restoration on a five-class scale from very good to poor. The tool is validated for the Comana Marsh on a second order tributary of the Danube River in Romania. A small-size dam and a system of concrete dykes was built to recreate a marsh upstream, in the floodplain. According to the tool: (i) the effects (e.g., surface-water area, depth) were a success compared to pre-restoration conditions, yet they could not recreate the historical conditions; (ii) new processes (e.g., anastomosing river pattern) appear to be functional when compared to scientific expectations; (iii) the river site gained hybrid features (i.e., rewilding in the context of human pressures). The effectiveness of restoring the Comana Marsh was estimated as being good. The tool could be further developed by integrating other groups of indicators based on stakeholders’ perspective. Understanding the theoretical results of river restoration could help policy-makers to gain confidence and further finance this domain underdeveloped in Romania.    

This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS - UEFISCDI, project number PN-III-P1-1.1-TE-2021-0600, within PNCDI III.