Thursday, March 1, 2018

Ten Things You Must Know about Stream Restoration, by Don Orth

In a world dominated by humans, managing fisheries must include restoring modified aquatic ecosystems and habitats.  Numerous approaches exist to achieve ecosystem restoration, habitat restoration, flood control, property protection, sediment management, water quality improvement, and aesthetic or recreational benefits (Wheaton et al. 2008).  Although many riverine specialists are involved in this work, we all must play a role in educating citizens on the basics of stream and riverine restoration.   In this essay, I summarize the ten things you and others must know to be effective stewards of streams and watersheds. 

1.   Stream restoration is not new.  Stream habitat improvement was the pastime of the wealthy from 1892-1931 (Thompson and Stull 2002; Bennett et al. 2008).  Government programs, such as the civilian conservation corps, provided cheap labor and expanded stream modification efforts from 1932 to 1941.   Most work done by a variety of entities from 1942 to 1967 had high failure rates, leading a long period of stagnation. Some installed structures hae high failure rates, while others persisted for long periods. For example, one log and rock dam constructed along the Upper Beaverkill River, New York, in the 1890s persisted for over 100 years (Thompson and Stull 2002).  Recently, stream restoration projects have increased in extent and number of projects, thereby creating a new industry (Bernhardt et al. 2005).   Though stream restoration techniques have a long history, what is new is the development of a stream restoration industry attempting to address more complex issues.   
Ad in American Forests on use of dynamite for stream realignment.
 2.  Most restoration projects manipulate the stream channel in short reach. Many of these small projects are of questionable value or un-evaluated.   Bernhardt et al. (2007), from a survey of 317 individual river restoration projects in the U.S.A, reported that only 46% of restoration projects even had success criteria.  Lack of criteria and the lack of monitoring undermines the credibility of stream restoration efforts for achieving positive outcomes.  Meta-analyses of macro-invertebrate and fish responses to stream restoration are not demonstrably positive (Stewart et al. 2009; Miller et al. 2010; Smucker and Detenbeck 2014; Kail et al. 2015; Roni et al. 2015; Rubin et al. 2017).  While many projects report a positive effect, one-third of projects had no or a negative effects (Kail et al. 2015).  The likelihood of failure appears to be high.  We cannot continue to assume that current practices of stream restoration provide “demonstrable physical, chemical, or biological functional improvements” (Doyle and Shields 2012, p. 500).   Part of the explanation lies in the scale of improvement. 

3.  Place matters!   Streams vary a lot, and basic physics of sediment supply and transport influence what and where treatments will be appropriate.  Streambeds are mobile, however, some are more than others.  Geomorphologists distinguish between colluvial, alluvial, and bedrock controlled channels as they develop their theories.  Furthermore, the upstream human-modifications of watershed and associated hydrologic and geomorphic changes may negate any potential channel restoration benefits (Doyle and Shields 2012).  Fish responses to stream restoration were significantly reduced as agricultural land use increased in the watershed (Kail et al. 2015).  Most evaluations of fish response to wood placement have shown positive responses for salmonids; those that did not did not address watershed issues (Roni et al. 2015).  Our scientific understanding of fish and macro-invertebrates, and past management of their habitats is based on small spatial scales and short time frames, whereas natural processes and human influences on large spatial scales and long time frames interact to create and maintain suitable habitat (Stoll et al. 2016). These studies and others support the need for improved strategies for prioritizing restoration projects (Stoll et al. 2016).   
Log and rock dam along the Upper Beaverkill River was built in the 1890s. (Thompson and Stull 2002).
4. Water quality criteria do not protect aquatic life.    Early guidelines for developing water quality criteria recognized the complexities of multiple stressors and variable field data, but laboratory based studies proceeded more rapidly. Consequently, the guidelines developed by experts established laboratory experiments as the primary source of water quality criteria (Buchwalter et al. 2017).  One model organism, Ceriodaphnia, is highly sensitive to pollutants; however, the water quality criteria developed from lab studies of Ceriodaphnia were not protective of many faunal groups, such as mayflies, stoneflies, crayfish, and mussels.   There are many instances where entire faunal groups were extirpated from an effluent that was deemed safe based on lab-based criteria (Pond et al. 2014).  Furthermore, we understand that the mechanisms of exposure and speciation of toxicants is critically important and cannot be ignored (Buchwalter et al. 2017).  Only a diverse body of scientific evidence can establish water quality criteria based on a more realistic weight-of-evidence approach.   

Stroubles Creek is a highly modified urban stream that drains Blacksburg, Virginia.  It displays all symptoms of the urban stream syndrome and much of the stream channel is buried underground.  Only short segments within town limits are daylighted and available for adoption. Photo by D.J. Orth. Inset illustration by Shannon L. White.
5.  Natural channel design is oversold.   This geomorphic, form-based method does not result in restoration of native biodiversity in degraded streams (Pond et al. 2014).  A process-based restoration approach that considers multiple stressors with stakeholders has the best chance of success (Beechie et al. 2010).  Restoration is also an oversold term.  Very seldom are we really involved in an “action of returning something to a former place or condition.”    Out-of-stream management practices may improve ecological conditions; however, in urban streams these practices will not return to reference conditions (Smucker and Detenbeck 2014).    

Stream mitigation banks (SMB) have necessitated the quantification of benefits created by projects so that credits can be banked and traded.  This “ growing field of SMB has the potential to reinforce the shift away from a stream restoration science, whose goals, standards of training, and legitimate content are defined by public sector scientists” (Lave et al. 2010, p. 694).   The private sector has provided incentives to deliver flood alleviation and public opinion is in favor of quick fixes for flood reduction (Langford and Shaw 2014).

"I suppose it is tempting, if the only tool you have is a hammer,
 to treat everything as if it were a nail." 
Abraham Maslow 1966

Fries Dam on New River was completed in 1903 and still operates as hydroelectric generating facility.  Photo taken September 21, 2015 by D.J. Orth.
6.  Recovery times exceed study durations.   Ecosystem processes take time to allow streams to “self heal.”  While most practitioners recognize this and design to enhance these natural processes, the published studies on stream restoration effects are usually too short.   Scrimgour et al. (2014) and Marttila et al. (2016) document the slow recovery in boreal streams after more than 14 years.  Just as it may be difficult to find a “silver bullet” for evaluating restoration success (Pander and Geist 2013), it is equally difficult to know the appropriate study duration without more long-term research on stream restoration.      
7.   Dams and barriers change everything.  Many dams and road-crossings have already had dramatic effects on our waterscapes, and the influence is only now apparent. Legacy effects are a dominant influence on present-day aquatic communities, and many dams now exceed their design lifespan.   Yet, stream restoration is based on the assumption that all components of the aquatic and riparian communities (both strong and weak dispersers) have opportunities to recolonize and re-establish aquatic communities.  In contrast, many rare or sensitive fishes have not recolonized streams due to movement barriers (Nislow et al. 2011; Quist and Schultz 2014).  Only recently have stream restoration efforts considered the need for extensive inventories of barriers and dams (Januchowski-Hartley et al. 2013).  Barrier mitigation should be a much higher priority for stream restoration. Culverts have shorter design lifespans than dams and ecological designs for culverts permit a longer life span, reduced maintenance, and improved flood event resiliency (O’Shaughnesy et al. 2016).  Future examination needs to be made for prioritizing dam removal or renew or adapt dam operations to future climate scenarios (Ho et al. 2017).  It’s way past time to evaluate the present value of our aging dam infrastructure and plan for a decommissioning and removal of dams.  It is time for large-scale reconnection of flowing waters. 
Pygmy snaketail dragonfly, Ophiogomphus howei, one of rare dragonflies in upper New River drainage.  Photo by Denis Douceta
8.  Invertebrates get no respect.  While biomonitoring of stream water quality with macro-invertebrates has a long-standing history, invertebrates do not get the same level of attention in stream restoration efforts.  We live in an ichthyocentric world, and some regions are simply salmocentric.  However, many major groups of invertebrates, including freshwater snails, mussels, crayfish, stoneflies, and dragonflies, are at far greater risk than salmonids; furthermore, a small percent of species have even been evaluated (Collier et al. 2016).   It took a generation to convince people that “fish need water too” and we need to begin efforts to understand, and then communicate, the functional roles and ecological requirements of stream invertebrates before it is too late.  Developing a conservation strategy for at-risk invertebrate species may be useful for evaluating and prioritizing stream restoration projects (Smith et al. 2015).      

 In Oregon's Bridge Creek Watershed, researchers built a number of beaver dam analogs to encourage increased beaver activity and restore healthy river habitat. Photo by Nick Weber.
9.  Stream restoration may require beaver restoration.  Beavers dominated the waterscapes of North America before European colonists arrived. Stream restoration practitioners are using the beaver in many situations to restore riparian and wetland ecosystems that support declining populations of Pacific salmon and trout (Pollock et al. 2015).  Although there are many human and beaver conflicts in our human-dominated landscapes, the use of beavers as partners along with human stakeholder involvement can provide numerous benefits to the landowners. 
10.  Multiple lines of evidence are needed in diagnosing stream problems.  Available evidence suggests that current stream restoration practice is not adequate (Doyle and Shields 2012).  The only recent clear example that demonstrates that restoration is a useful conservation tool for fishes was the work on the Okaloosa Darter Etheostoma okaloosae on Elgin Air Force Base (Reeves et al. 2016).  “Modern science teaches us that a single line of evidence is not adequate and that a body of diverse work is the most effective way to establish convincing principles that stand up to the test of time.” (Buchwalter et al. 2017, p 290).  Remediation of stream degradation is very expensive.  Before any proposed remedy is implemented, a formal analysis of causes based on multiple lines of evidence should be completed.  Some case studies exemplify this process that can lead to identifying causes and appropriate remediation (Norton et al. 2009).  

Fisheries Biologist Bill Tate conducts an underwater census for Okaloosa Darter Etheostoma okaloosae from a creek on Eglin Air Force Base, Florida.  The Okaloosa Darter increased in abundance and distribution in response to stream restoration treatments    Photo by Carlton Ward Jr.,
True restoration success depends on prioritizing certain actions over others (Beechie et al. 2010; Roni et al. 2015; Stoll et al. 2016).  First and foremost, we should protect high quality habitats.  This requires systematic conservation planning to prioritize aquatic sites for protection and improve the overall regional habitat quality.  Next, we should improve water quality and quantity, and restore watershed processes.  The final step, only after the other actions, is to work toward improving instream habitat.  This means we often will need to say “no” to certain unwarranted stream restoration projects.       

Stream restoration is a rapidly evolving science (Bennett et al. 2008) and the private sector is driving the science (Lave et al. 2010).  There is need for support of the science of stream restoration in order to inform the practice.  Research with long study durations and a priori power analysis would be very instructive for future stream restoration (Vaudor et al. 2015 ).

The practice of stream restoration science must be more holistic, as restoration strategies are based on multiple societal values and beliefs (Wheaton et al. 2008).  Furthermore, we need to address causes and restore processes rather than patch symptoms in the channel (Vietz et al. 2015). Integration of stream channel and riparian habitats into restoration is an integrated effort (Turunen et al. 2017) that requires multiple indicators of restoration success (Pander and Geist 2013).  Doing the restoration “thing right” will involve many scientific specialists; however, deciding what the “right thing” to do will involve dealing with people in the local social and cultural contexts.  Involving more local citizens in river restoration can serve to promote citizen awareness of both the need and value of intact river ecosystems. 

"Some problems are so complex that you have to be
highly intelligent and well informed just to be 
undecided about them."  Laurence J. Peter 

Restoring degraded streams, especially in highly urbanized watersheds, is often a ‘wicked problem.’ Rigorous evaluation is still needed to learn from successes and failures, and reduce uncertainties (Wheaton et al. 2008; Bouwes et al. 2016).  Doyle and Shields (2012) advocated for a greater emphasis on avoidance and minimization of streams to account for high uncertainty in current stream restoration practice.      

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  1. Nice synopsis. I agree with your conclusions that instream habitat improvement is the last step in the process. Unfortunately, that step is often used with considering the broader picture of what degraded the system in the first place.