We think the purpose of stream restoration is to improve ecological health.
We think that streams can be treated like patients.
Streams are complex organic systems we can help heal, and not just physical things we design
Try as we might, we can’t design and build natural biotic communities or biophysical processes.
But we can help them recover by relieving the anthropogenic impacts that disrupted them.
Ecological process-based restoration is healing, and healing requires patience.
Mostly this talk is about semantics.
It’s about the day-to-day words we use in the practice of stream restoration and what they
It’s about how the words guide what we do and why we do it.
I wonder if using different words could help us see these problems differently and open our
minds to broader solutions.
The concepts of ecological health and healing are nothing new.
In 1999, James Karr said that health—as a word and concept in ecology—is useful precisely
because we are familiar with it. It’s intuitive. People get it.
As a term, health commonly applies to people and organisms, but it also applies to ecosystems
since they are also complex biophysical systems.
Most practitioners use the concept metaphorically.
• Joe Wheaton, who spoke to us yesterday, uses stream health to explain process-based
restoration and giving streams a “healthy lifestyle” before jumping right into “surgery”.
• He has fun with the analogy, talking about the importance of exercise (dynamic
geomorphology and ecology) and a proper diet (structural elements like wood).
• Could your river be a “foodie?”
• Of course, all this is meant to explain the importance of natural processes in maintaining
healthy dynamic streams and deferring the detailed decision-making to Mother Nature.
As Joe said yesterday, it’s about humility.
We like this approach, and we think it’s worth taking one step further.
Stream health can be more than a metaphor. It can be a mindset that guides restoration.
To do this, the term “stream health” has to be operationalized by defining it and finding ways to
As an operational term, stream health has to be based on something real. It can’t just
be a “term of art”.
It must be objective.
I’ve been in stakeholder meetings where the moderator went around the room asking
“what’s a healthy stream to you?” as if the meaning could be derived from a poll of
stakeholder interests. That’s not what we’re after. It’s too arbitrary and too subjective.
I’ve also been to lectures where the professor said stream health and restoration goals
ought to be based on "what people want, and not what an ecosystem needs.“ I couldn’t
We have to be careful not to define stream health in terms of our own human values
Stream health has to be an inherent property of the stream ecosystem, not just the ways
we want it to serve people.
Peter Skidmore and James Karr get us closer to operational definitions.
• Both use a measure of biological condition.
Peter specifies aquatic and riparian species diversity
James specifies biological integrity.
• Both authors also say stream health is roughly inverse to the degree of human disturbance.
The key point is that ecosystem integrity is at its greatest when all the native parts and
processes that coevolved together are intact.
Stream ecosystems change and adapt to human impacts, of course,
but when natural processes are disrupted, there is a resulting loss of function.
When we talk about functions, we are talking about the full suite of natural hydrological,
geological, and biological processes that operate in concert on a naturally healthy stream.
The upper diagram shows stream health as a spectrum.
Pristine streams (on the left side) are the least impacted, healthiest, and have the most
intact natural processes.
Streams on the right are the most altered for human use. On these, natural ecological
functions have largely been traded off to optimize them for specific human purposes.
Most streams are somewhere in the middle zone—partially used—the zone of
The upshot is stream ecosystems are naturally healthy until we modified them
(either intentionally to meet important human needs—or unintentionally)
And stream health suffers when natural processes are disrupted.
• LeRoy Poff offers this hope: Just as rivers have been incrementally modified, they can be
That is, when we are done using them, or when we learn how to use them more efficiently,
they can be restored back to health. That’s up to us.
Now let’s bring the health concept back to mainstream meanings.
On the right we’ve listed some common criteria used to define human health,
and the left shows how these apply to streams.
A healthy person performs her vital functions normally or properly.
A healthy stream likewise performs its vital functions normally or properly.
We call these natural processes.
Human health is anatomic, physiologic, and psychologic integrity,
Stream health is physical and biological integrity.
Healthy people recover from stress.
Healthy streams recover from stress.
This is what we mean by resilience.
And if human health means the ability to perform valued roles,
The valued roles healthy streams play are called ecosystem services.
Now I’m going to tell you a story.
This is one of the first streams Jessica and I got to work on together in the early 2000s.
This property was used heavily used for 140 years of ranching. It’s mostly retired now
And it’s sick. So we called in a restoration professional for advice.
Our professional came out to the site with us and said
“yes, this stream certainly has problems. I can help you, but first you have to tell me what you
want it to be.”
“Umm, we want it to be healthy again.”
“Well, you’re going to have to be more specific.
What do you actually mean?
What are your objectives?”
“Hmm, well, we guess to start with, we’d like there to be more native plants and animals”
“OK. If you tell me the species you are interested in and what type of habitat they need, I’ll see
what I can do.” “But you need to be specific.”
“And obviously the first thing we have to do is get this channel stabilized. Otherwise any habitat
we build won’t last.”
So, we did our best to think up some discrete habitat and biological objectives.
And eventually, after lots of coaching, we settled on a short list that included bank erosion, pool
depth, riparian shrub cover, and fish.
We were pretty proud of ourselves.
And our professional now had what he needed to move forward with design.
And, soon thereafter, construction.
Here we are 12 after the digger trucks went home.
Biotic response?... Dismal.
Looking back, it’s embarrassing how little effort it took to convince us that stream restoration
was about designing and building stable habitat.
Even if this project did meet all its objectives (which it didn’t) it probably wouldn’t have enabled
natural processes or improved stream health very much.
So what went wrong?
Our point isn’t to criticize the design or the construction.
We are telling this story so we can talk about semantics.
It’s been 16 years since that initial conversation, and it finally dawned on us that somewhere
during that brief talk we lost track of ecosystem function, natural processes, and stream health.
As soon as we started talking restoration, the conversation shifted from healing a sick stream to
designing and constructing habitat.
Our stream was no longer a patient. It became a design-build engineering exercise.
So now we’re thinking…
If we really want natural processes and ecosystem health, perhaps the design-build mentality
isn’t the best way to get there.
But here’s the thing...
Every single restoration project we know of uses design-build language.
Design is a decision-making process in which science, math, and engineering are applied to
create things that work effectively, efficiently, and safely.
The key to success in any design (like this one of a house) is to fully understand the intended
purpose and to have clear and specific objectives.
• If you have a definite purpose and specific objectives, we all assume we can use this
process to design a river.
The next step is to implement the design and build the project.
Here is Bob the Builder making sure the house is built to design specs.
• And here are some guys implementing a river design in the construction phase of their
One expectation of the design-build mentality is that once your project is built, the work is
But naturally we want the stuff we build to last and continue to function, so we come in
prepared to do maintenance.
Maintenance is the activity of keeping the things we build in good condition by checking them
regularly and repairing them when necessary.
Anyone who owns a house knows plenty about this.
• We do this for rivers too. Here is maintenance on a project where the river has been
repurposed for a municipal kayak park.
The design-build mentality works great when we’re manipulating rivers for a specific purpose,
like the kayak park in the previous slide.
Or when engineering a river to do something like protect a road as in this example.
• Well, I mean it doesn’t always work, but at least it is the right model for thinking about these
types of projects.
The reason the design-build model applies in these cases is that they have specific
anthropogenic purposes and concise, discrete objectives.
And that’s precisely why it doesn’t work for process-based restoration where the guiding
image is a dynamic, ecologically healthy river.
Dynamic ecology isn’t easily distilled into discrete objectives that can be designed and built.
In restoration we aren’t going for specific objectives.
Our aim is to reestablish normative rates and magnitudes of the physical, chemical, and
biological processes sustain river and floodplain ecosystems.
We are masters of designing, building, and maintaining things to meet specific objectives.
But we are not so good at designing, building, and maintaining natural physical, chemical, and
Not even close.
I think Mathew Johnson and his colleagues said it best in their new biomic restoration paper:
We cannot replicate physically what biogeomorphology does organically.
We wouldn’t know how
Not even if we had unlimited resources.
They go on to say that stream restoration comes down to empowering the agents responsible
for driving biogeomorphology.
We have to provide the opportunity for plants and animals (and all the other natural biotic and
abiotic components of a healthy ecosystem) to do something only they can do: build,
maintain, and adaptively manage habitat.
Empowering natural agents to reestablish natural organic processes.
By Jove! I believe we just rediscovered the definition of healing!
If it’s healing we’re after, then why don’t we use the language of healers rather than forcing
ourselves through the language of builders?
Rather than treating restoration as a process of designing, building, and maintaining habitat,
We can look at it as diagnosing the causes of impairment, prescribing treatments, and following
up with ongoing care to manage health of the organic systems we call streams.
In so doing, restoration becomes less about the kinds of things we can DO to make the stream
work the way we want
And more about the kinds of things we can UNDO to restore the way the stream works
If we think of it as healing, restoration is about correcting anthropogenic disruptions to natural
processes and helping them get working again.
Just like Tim Beechie said in 2010.
And just like Damion and Joe said yesterday.
How we employ this mindset, in practice, is something Jess and Brad and I have been working
on for the past 12 years. We could do a whole workshop on it.
But here’s the gist.
Rather than design a stream to meet a specific purpose, we DIAGNOSE it to identify the
Like a medical diagnosis, we use detailed history and physical examination to target the root
causes of impairment and decide which can be treated.
This approach forces us to be explicit about expected outcomes,
It forces us to match the scale of restoration to the scale of the problem,
And it forces us to tailor restoration actions to local potential.
It aligns our vision with the four principles of process-based restoration.
Instead of building or doing construction, we apply treatments.
The purpose of treatments is to relieve the diagnosed causes of stress and to assist recovery
after a stressor is removed.
Treatments can be interventions that are like surgery in that they involve physical
And sometimes you get to use digger trucks, just like the builders do.
And treatments can be therapies which are passive approaches that guide healing with a lighter
Unlike building or construction, treatments aren’t the end game. They are means to an end.
Positive treatments enable and accelerate natural healing processes.
They empower natural agents.
And finally, rather than maintaining the things we build so that they last,
In restoration, we should expect change.
The design-build language we use every day implies immediate results. And we are used to
evaluating success by comparing pre-construction to post-construction conditions.
This view has to change if we expect to restore dynamic healthy ecosystems that function by
Healing is not immediate, and it usually isn’t fast. It takes time, and there is a lot of uncertainty.
Like health management, restoration is an ongoing process.
We need to expect and plan for ongoing care and continued support during the healing process
We need to learn patience.
We think changing our mindset from a design-build mentality to a healing mentality, and using
the words that reflect that, will lead to better restoration.
Or at least it is worth a try.
Next time you find yourself using familiar terms like “design”, “build”, “construction” and
“maintenance” in your restoration projects, pause for a second and think:
Am I really empowering nature’s river restorers?
Am I enabling natural processes?
Is my guiding image a dynamic, healthy ecosystem?
Them’s ain’t JUST semantics.
That there’s stream health!
And stream health is something we all oughta get riled about!