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Introduction to Stream Restoration
Week 1
Copyright © Andrew Collison 2002
Photo from Alberta Fish Habitat Manual
Course logistics
• This is a quantitative topic: math as required
• In-class work: GIS, field work & report
• Quick notes
• Skills test
Wide range of projects called “Stream Restoration”
Small-scale bank stabilization or revegetation
Complete channel realignment or redesign
Arlington, VA Dept. of Environmental Resources
SR is not well defined but there are several consistent elements
Arlington, VA Dept. of Environmental Resources
• A desire for a more “natural looking” channel
• Integrate ecology & geomorphology with engineering
• Work with natural processes (self-sustaining design)
• Avoid hard structures
Primary reasons stream restoration is done in the United States
WQM – Water Quality Mgmt.RM – Riparian Mgmt.IHI – Instream habitat improvementFP – Fish PassageBS – Bank stabilizationFM – Flow modificationA/R/E – Aesthetics/recreation/educationCR – Channel reconfigurationDR/R – Dam removal/retrofitSM – Stormwater mgmt.FR – Floodplain reconnectionISM – Instream species mgmt.LA – Land acquisition
From Bernhardt et al., 2005
Current Status of field• >$1 billion is spent each year on stream restoration
projects (Bernhardt et al., 2005)• Little predictive science to back up restoration designs• Few post-project assessments done (funding)• High rates of design failure
– Survey of 161 fish habitat structures in Oregon/Washington found 18.5% failed and 60% were damaged in 2-10 year event (Frissell and Nawa, 1992)
– Survey of 400 habitat enhancement structures in Alberta found that 33% had low or zero effectiveness (O’Neil and Fitch, 1992)
• Vast majority of projects are designed using “natural channel design” coupled with the Rosgen reference reach approach
There is a current “standard method” for stream restoration,
called Natural Channel Design, or the Rosgen method
Dave Rosgen, P.H., Ph.D
Wildland Hydrology
Ft. Collins, Colorado
So why don’t we just teach the Rosgen method?
• It’s a little too “cook book” in our view
• Insufficient emphasis on basic process understanding
• There are plenty of other places where you can learn it (for a fee…)
Elements to the Uof M/NCED* approach
• Emphasis on design based on analysis and prediction, not analogy
• Emphasis on placing SR projects in watershed context
• Emphasis on integrating historical records
*NCED is the National Center for Earth-surface Dynamics, an NSF Sci-Tech center devoted to surface processes, including SR. More about NCED later.
Basic steps to a restoration project – most of these steps require an interdisciplinary approach
• Problem identification – what is wrong? Is it actually a problem?
• Societal context –stakeholders interests, funding sources, regulations, cultural issues, etc.
• Define achievable goals - be specific• Assess site at watershed-level (best to act at watershed
level if possible, or at least understand constraints on system), and at the reach-level, including longitudinal and lateral connectivity
• Identify alternatives, evaluate, and choose design • Implementation – including construction monitoring• Monitoring and assessment; Adaptive management
Goals of this course/program• Balance basic fundamentals of fluvial geomorphology,
hydrology, and ecology with practical information • “EMT” level of understanding for restoring damaged
streams• Focus on ability to evaluate and critique restoration
project (learn from past failures and successes)• Tools to design relatively simple restoration projects on
small streams• Turn you into effective team members on restoration
projects• Give you the tools to do both a watershed-scale
assessment and a reach-scale analysis of a potential site and make you think about a river over multiple temporal and spatial scales.
This program will NOT teach you…
• How to design large-scale restoration projects: this requires a team of subject-area experts and years of experience
• How to work in highly urbanized settings, where life and property are at risk
• Rosgen’s toolbox for natural channel design: There are numerous short courses to learn this tool, including a series by the MN DNR
Common major considerations in restoration design
• Habitat:– Water temperature– Topographic complexity– Desirable ranges of U, h
• Channel stability – ability to convey high flows without major changes in form
• Pollutant reduction (e.g. susp. sediment)• Nutrient processing – especially N, P• Esthetics & recreation
Overall Words of Advice for the River Restorer: FIRST, DO NO HARM!
“There is renewed emphasis on recovering damaged rivers (Baringa 1996). Along with this concern, however, people should be reminded periodically that they serve as stewards of watersheds, not just tinkerers with stream sites. Streams in pristine condition, for example, should not be artificially “improved” by active rehabilitation methods.
At the other end of the spectrum, and particularly where degradation is caused by off-stream activities, the best solution to a river management problem might be to remove the problem sources and “let it heal itself”. Unfortunately, in severely degraded streams, this process can take a long time. Therefore the “leave it alone” concept can be the most difficult approach for people to accept (Gordon et al. 1992).”
From FISRG, 1998, Stream Corridor Restoration, p. 8-2.
Restoration State of ArtCraig Fischenich
• State of practice generally lags state of art by about 10 years – not true for restoration
• Stream restoration has evolved as a practice rather than a science
• Current practice generally reflects the state of art from about 50 years ago
• Progress is slow and redundancy rampant
Restoration is the return of the form and function of an ecosystem to some pre-disturbance condition.
We Can’t We Can: (or Won’t):
Characterize evolutionary changes in streams
Develop sophisticated analytical tools and models
Identify specific causal mechanisms of disturbance
Optimize habitat for a particular species or guild
Determine when they will occur or quantify magnitude
Get practitioners to use them
Assess the cumulative effects of multiple causes
Optimize habitat for a community across trophic levels
We Can’t We Can: (or Won’t):
Stabilize channels and banks
Identify project objectives
Design systems that mimic reference conditions
Characterize ANY action as restoration
Allow for a full range of dynamic processes
Relate these to meaningful standards or metrics
Ensure that they are appropriate or functional
Fully restore both the form and function of most systems to pre-disturbance
We Can’t We Can: (or Won’t):
Identify broad ecosystems in need of restoration
Develop monitoring plans
Use multi-disciplinary approaches in design
Acknowledge risk and uncertainty
Execute comprehensive, integrated restoration over large spatial areas
Fund and execute monitoring plans
Use inter-disciplinary approaches in design
Quantify and manage risk and uncertainty
Six Points in Ten Minutes:----------------------------------------------------------------------1. Extent of river restoration, scale of investment2. Lack of monitoring and evaluation3. Most projects designed using empirical approaches from 1950s, need to update (But it’s not just hydraulics/sediment – big picture!)4. Recognize changed conditions of rivers continuum: wilderness ---- fully urban5.Cultural preference for stable, meandering channels?6. Implications for goals, assessing success---------------------------------------------------------------------
Southwest Catchments in Rio Grandeand Colorado River Basins Shah, Dahm, Gloss
California - Sacramento-
San Joaquin Basin Kondolf
Northwest Pacific NW, Interior Columbia BasinNorthern Rockies Goodwin, Stanford, Clayton, Relyea
SoutheastGeorgia, North Carolina, South Carolina, Kentucky
Sudduth, Meyers
Chesapeake Bay NY, Penn, MD,
VA, WVA Hassett, Palmer, Bernhardt, Hart
Upper mid-westMichigan, Indiana, Wisconsin
Alexander, Allan, Gergel
Central US Large RiversMissouri and Mississippi River Basins
Galat
Extent of Restoration in USNRRSS (National River Restoration Sci Synthesis)Seven nodes covering 20 states
Extent of Restoration: NRRSS results
Nationwide: 38,000 records fr 20 states includedData sources mostly large data bases
Testing completeness by checking with local watershed experts
In California, one test is the Russian River basin -211 records in database vs 878 from grad student’s detailed surveyExtrapolating: up to 400,000 projects nationwide
Conservative estimate: $15-17 billion (Palmer et al in review)
Given the magnitude of the investment to date Surprisingly little objective post-project appraisal
Only 14% NRRSS projects indicated monitoringIn California (4,000 records): 22% indicated monitoring, but only 11% of those included specifics that make it credible
Very few studies assessing restoration success. Only studies with large ‘n’ are surveys of habitat enhancemt projects in western N. America – these suggest appx 50% success rate - lower success rate for older projects
Thus, no reason to assume that our projects succeed
Why so little objective monitoring/evaluation?
Most agencies prefer implementation (many funding sources only to implement)
No payoff in going back, esp if you find “failure”
A question of culture: Engineering project vs scientific experimental “Failure” stigma vs “Learning Success” concept
Institutional difficulties e.g., restoration projects done for mitigation (failure not ok!)
Prevalence of designs based on - empirical relations (40-y old concepts) - stream classification
More recent science not widely integrated in restoration projects. NCED to the rescue!
Caveat: restoration doesn’t necessarily imply physical alteration of the channel - catchment changes - better understand system, may not need to intervene
Recognize changed conditions of rivers continuum: wilderness ---- fully urban
Goals and Objectives should depend on CONTEXT - need to be realistic about what’s possible and appropriate in a given context
River ‘restoration’ is fundamentally a social activity - highly urban project as ‘gardening’ – that’s OK - in less altered settings, may be possible to preserve/restore physical/ecological processes Usually restoration trajectory different from degradation trajectory. Examples plotted on 2D field connectivity-dynamics
Social FactorsTheir importance in restoration now widely appreciated. - But it’s not just about stakeholders, surveys, and interviewing local residents
Cultural preferences may be driving many of our restoration designs, though we may not realize it
e.g. a cultural preference for stable, single-thread meandering channels?
An Example:
Cuneo Creek,Tributary to Bull CkHumboldt Redwoods State Park
Basin logged in1950s-60s, high sediment yields.
Aggradation, braided channel
Cuneo Ck
Bull Ck