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Stream Restoration, Improvement, or Manipulation - Whatever You Want to Call it...

What's in a name? Well, quite a bit. I think that names are important. I generally chose "manipulation" over "improvement" because I think that manipulation is a little more neutral. Improvement certainly has a different connotation than does manipulation. And not everyone might agree with it being an "improvement" and I'll talk about below.

Cars as habitat structures
Stream bank "structures" in a West Virginia stream. Looks can be deceiving, this was a great Brook Trout stream and the rusted out cars held some incredible Brook Trout.

There is at least a bit of controversy involved in stream habitat projects. There are no shortage of people that like to complain about stream projects. To be honest there are a few project that I am not fond of for any number of reasons. There are projects that changed streams I liked - often some challenging, tight, "roll-casty" streams that were less fished. Or manipulations that drew anglers to previously underfished streams or stream reaches, or they decreased the fishability of some streams - at least how I like to fish. You turn a good dry fly stretch into nymph water, I am not going to be a fan (yes, I'm a bit of a dry fly snob). But those are all pretty selfish reasons. On the "roll casty" water that "got ruined" by improvements, a few of my fishing buddies instantly know what reach I am talking about - even if that "improvement" was completed nearly 15 years ago. Yes, I can hold a "grudge".

Stream manipulation project on a popular coulee stream
A stream manipulation project after the 2018 floods had greatly alterd this reach quite greatly. This is in a continuously grazed pasture - hence the short vegetation along the banks.

I think it is pretty undeniable that there are (at least) four things that have greatly improved trout fishing in Wisconsin.

  1. First and foremost, the Clean Water Act (CWA) - and to a lesser degree the Clean Air Act (CAA) - have helped improve water quality. Yes, it is not perfect but our water and air are better than they were before the CWA and CAA were enacted. After all, there are reasons that these pieces of legislation were enacted. In many eastern states, the CAA has been every bit as important in improving water quality as the CWA because it has decreased acid precipitation. Here in Wisconsin, mercury pollution has been reduced due to the CAA. I say first and foremost here because without clean, cold water, you have no trout.

  2. Second - not necessarily in chronological order - is the reduction of the major sources of degradation. Here in the Driftless Area, that is contour plowing, grassed waterways, and other conservation practices. Here and other parts of the state, it was recognizing that straightening streams was a bad idea. In other parts of the state, it is that they are healing from historic forestry that altered their landscape much as agriculture altered the Driftless landscape. This is, of course, not to say that sources of degradation are gone but in general, these are the good old days for trout fishing in Wisconsin.

  3. Third, we have improved the carrying capacity of our streams by increasing the habitat and cooling the water temperatures by "getting the water moving". I think that is often an overlooked part of habitat improvements - they reduce the heat sinks that warm up streams. I know I have taken temperatures above and below riffles or a series of riffles and it is amazing how much cooler streams became after moving through riffles.

  4. Lastly, wild trout management - that is not stocking trout over self-sustaining populations. Trout fishing is a lot different than it was 35 years ago when I first started trout fishing (yeah, I'm old...). There are more wild fish and fewer stocked fish. A quick look at Wisconsin DNR's fish stocking database shows that to be true. Of course, this was made possible largely because of the first three points.

Late winter stream
Early spring / late winter from a small stream with a nice wintering hole.

Habitat management is just one part of puzzle. Certainly water temperature, quality, and quantity come first - without enough clean, cold water, there are no trout. After that, habitat manipulation has been shown to be pretty effective at improving trout populations and helping produce wild, self-sustaining trout populations.

Stream habitat manipulations are certainly nothing new. Clarence Tarzwell was writing about manipulations to trout streams in Michigan (Tarzell 1931) and how it improved trout fishing (Tarzwell 1937). Wisconsin has certainly been a leader in the area of trout stream manipulations. Bob Hunt's work on Lawrence Creek was some of the first published literature on stream habitat manipulation. His papers are still quite influential today - including one that demonstrated a need for patience after projects (Hunt 1976). Ray White, a contemporary of Bob Hunt, was in Wisconsin before moving west and wrote about projects like the one on Big Roche-a-cri Creek (White 1975). Ray continues to educate about habitat management. And a number of Wisconsin DNR publications on trout stream habitat management were highly influential here and elsewhere (link). More recently, Dave Vetrano and his LUNKERS (Little Underwater Neighborhood Keepers Encompassing Rheotactic Salmonids) design became a staple on many Driftless streams. And with the Trout Unlimited Driftless Area Restoration Effort (TU-DARE), we have leveraged important sources of funding to do what many Midwestern TU chapters were doing but at a much larger scale. Throughout Wisconsin, Minnesota, and Iowa's Driftless (or at least Driftless-like topography) Area, streams have been manipulated - and I would argue generally improved - at a record pace.

Older LUNKERS on a stream corner
A series of LUNKERS on the corner of a Driftless Trout stream. More recent work lowered the water level of the stream.

What I would not call what is happening to most Driftless streams is "restoration". And I think that is a pretty important distinction - back to Shakespeare and what's in a word. As I have written about a time or two (see the suggested posts at the bottom), Driftless streams and the valleys they run through have been greatly altered. And I mean GREATLY altered. Streams and their valleys been altered to the point that restoration is hardly possible and I think that point is overlooked or ignored by many. Our streams and valleys are an entirely unnatural setting with many feet and millions of tons of sediment that should be on the hills filling the valleys. When I hear how we should let nature take its course or how unnatural stream improvements look (more on that later...), I know I am hearing from someone that is a bit oblivious to the reality of how our streams and their valleys have been altered. Our streams are unnatural and short of hauling millions of tons of sediment out of the valleys and back to the hills, that is just going to be their reality.

There is a case of true stream restoration I am familiar with in Wisconsin - the East Branch Pecatonica restoration project. As you can imagine, it is hugely expensive to truck sediment from the valleys. For most stream projects, hauling soil is one of the largest project expenses. So typically, instead of restoration we deal with the streams in their rather "messed up" valleys. The banks are sloped back and streams are allowed easier access to their floodplains. Banks are often armored with some rock - though generally less than was used a decade or two ago. It is not restoration of streams to a previous condition but it effectively allows the streams to behave like streams rather than being confined to their incised channels.

Stream manipulation has been sort of an evolutionary process. Over time, practitioners have figured out what works and where those techniques work. And equally important, they figured out what does not work and where it does not work. I know of at least a few reaches, generally fairly high in the watershed, where "improvements" have failed at least once, sometimes more than once. And I know of other reaches that have endured several significant floods and continue to hold up. These projects are rather expensive and time-consuming so getting it wrong is quite costly. More often than not, they are getting it right - and fixing what was not "gotten right".

Recently improved reach
A recently manipulated reach that you can hardly tell was only a year ago, quite torn up.

Another common criticism of stream manipulation projects are that they look "unnatural". My response is twofold, first, yeah - the valleys they are in are unnatural so how are they supposed to look natural? Those stream banks and valleys should be several feet lower so the streams are flowing in a quite unnatural setting. And while the "golf course" comments have some merit, the only projects that look like golf courses for any period of time flow through continuously grazed pastures, a rather unnatural setting. Given a bit of time - and in our rather productive soils and our relatively wet climate - it does not take long for riparian vegetation to rather quickly "hide" most stream manipulation projects. I know of many projects that have rather few pieces of evidence that work had been done. As for the "golf course streams" that run through cow pastures, imagine what those streams would look like if cows had free access to streambanks.

Recently restored reach
Another recently manipulated reach that looks much better than it did after the 2018 floods.

The evidence for how well stream improvements have worked is not always as overwhelming as you might think (Bond et al. 2003, Stewart et al. 2009, Palmer et al. 2010). Certainly, I think that the evidence for how well they have worked in the Driftless Area are rather unequivocal. However, that was largely after dealing with our water quality issues first and that our largest source of degradation - cultural sediment filling valleys - is a historic rather than on-going source of degradation and it lead to decreases in habitat quality. In many other parts of the world, the degradations have effects on water quality or quantity more than they affect in-stream habitats which are most easily "improved".

2018 flood effects
Damage from the 2018 flood event - many streams became much wider, shallower, and contained much less fish structure.

My opinion is that habitat manipulations projects are some of the most cost effective things we do to our streams. There are certainly watershed issues that need to be addressed in many places. As I wrote about in the last post about climate change, flooding, and stream manipulation, watershed projects are quite expensive and probably the domain of agricultural agencies like the NRCS. Trout Unlimited certainly has a role to play but it is more in the identification of issues and assisting landowners with finding resources to help. As we have continued to install habitat projects, we have gotten better at identifying where to use particular techniques. And to efficiently use our rather limited resources - both "human capital" and financial resources - it will be increasingly important that we continue to learn what works (and what does not).

Put your thoughts in the comments. What is your chapter or the WDNR habitat crew doing in your area and how has that changed in the last decade or so?

Links of interest


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Really like the discussion this post brings up so thanks for writing it.

I remember the first day of a restoration ecology course in grad school what based on this exact topic, what are we actually doing and what's in the power of a name? That professor's point was that in many cases what we are striving for is remediation, not restoration because restoration indicates returning to a pre-disturbance condition. That's similar to what you mentioned with the point on things not looking natural because they're part of a larger impacted area (e.g. the river valley).

Instead his point of that lecture was using remediation as our term focuses on trying to improve your site based on what is degrading…


Mr. Welter knows his stuff. I wouldn't argue with anything in his comment. There's no doubt that stream manipulations have in many places improved our fishing. I've enjoyed fishing in the Driftless on reaches that would have been fishless without the stream work.

I grew up on Lake Superior's North Shore. The streams there were compromised by logging 100 years ago. There are places where later WPA projects improved the trout habitat with rock dams and wood ramps and logs, and some of those old workings are still holding fish.

But stream manipulations don't always work. In Wisconsin I fished a sandy stream that had received a lot of attention in the past, and when I got there some high…


john welter
john welter
Nov 26, 2023

Thoughtful piece, Jason, and especially tuned into widespread stream conditions here in the Driftless Area. There’s plenty of evidence worked-on streams work better than degraded ones: improved fish and invertebrate numbers and diversity, healthier water temps and drought resistance, more resilience against our frequent & intense floods of late, reduced soil loss and phosphorus loads (which affect downstream communities adversely and expensively). Techniques are tested against these challenges and modified going forward. Since 2003, it’s resulted in a whole new generation of approaches. Improving durability against flooding is an ongoong goal, but we know some rock edging is essential to hold banks in floods, as is bank sloping to provide a functional flood plain. Is upland land use change sufficien…

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