Compilation and Assessment of River Restoration Evaluation Metrics
Project ID: 7592
Principal Investigator: David Gaeuman
Research Topic: Sediment Management and River Restoration
Funded Fiscal Years: 2014
Keywords: "stream restoration" "monitoring" "evaluation" "ecology"
Beginning in the 1990's, a growing number of river restoration practitioners, funders, and regulators began advocating for monitoring and evaluation of completed projects [Bernhardt et al. 2007; Kondolf 1995; Kondolf et al. 2007; Palmer et al. 2007]. Reviews of restoration projects found that many projects are deemed "successful" by designers, but very rarely is that success based on specific ecological indicators [Alexander and Allan 2007; Jähnig et al. 2011]. River restoration has also moved toward more multidisciplinary and multi-objective approaches [Gregory et al. 2008] that require more complex monitoring and evaluation.
With a growing interest in fiscal accountability, restoration programs are developing increasingly comprehensive monitoring programs to document attainment of goals. Evaluations initially relied heavily on easily quantified metrics such as acres restored, length of streambank restored, and riffles or pools created. Evaluation programs increasingly seek to develop more useful metrics that can connect intermediate hypotheses of restoration with ultimate restoration goals that are often challenging (or require long time periods) to measure directly. With restoration now a core USBR mission, the question of how to evaluate success assumes greater importance.
With restoration programs being implemented in connection with multiple USBR projects, we pose the question, "How is restoration success being evaluated in these rivers?" While each river is unique, there are likely commonalities among the diverse settings that would provide a basis for drawing lessons from experience that can inform future evaluation efforts. Thus, a corollary question can be stated, "How can we use USBR's experience to date, along with insights from current geomorphic and ecological research, to design more effective evaluation metrics?
Need and Benefit
While restoration is being undertaken in association with multiple USBR projects, to date there has been no systematic assessment of restoration metrics used, nor an evaluation of the circumstances under with they are most applicable. Despite growing interest in monitoring and evaluation of completed restoration projects [Bernhardt et al., 2005; Bernhardt et al., 2007; Kondolf, 1995; Kondolf et al., 2007; Palmer et al., 2007], evaluation efforts have not been systematic or coordinated [Bernhardt et al., 2005; Wohl et al., 2005]. Further, some restoration evaluations have simply adopted metrics from bioassessment or physical habitat assessment used in water quality programs, such as the EPA's Rapid Bioassessment Protocol (RBP) [Lazorchak et al., 1998] and the Ohio Qualitative Habitat Evaluation Index [Rankin, 2006]. Why these have been commonly used [e.g. Moerke et al., 2009; Purcell et al., 2002; Tullos et al., 2009], they may not be appropriate for restoration assessment (Table 1). For example, these water quality evaluations often include indicators of sediment deposition, with the implicit assumption that sediment is negative. However, current geomorphic and ecological research demonstrates that sediment is essential to riverine ecological health, and in fact much of the TRRP is based on increasing the input of coarse sediment to the channel downstream of Lewiston Dam (e.g., Gaeuman 2013).
Intermediate habitat goals (e.g. habitat complexity) have been increasingly criticized [Palmer et al., 2010] and ultimate biological goals often require intensive monitoring for long time periods. In our review, we will seek specifically to identify and catalogue examples of evaluation metrics that identify functionality of intermediate goals. Connecting intermediate targets to ultimate ecological goals could eventually help direct monitoring and evaluation to become more effective and efficient.
The final report will include a database of all metrics being used to evaluate USBR restoration projects, with each metric contextualized within relevant ecologic and geomorphic theory, and with emphasis on functional, intermediate metrics that can be linked to ultimate biological objectives, as potentially cost-effective and useful evaluation tools. We expect the report to be a useful reference document for projects elsewhere, and we will therefore post the report online and post links on pertinent websites and email distribution lists.
A journal article will be submitted summarizing the research results, and results will be disseminated through a conference presentation.
This information was last updated on May 23, 2015
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