Association of State Wetland Managers - Protecting the Nation's Wetlands.

The Compleat Wetlander: What’s Wrong With This Stream? Part II

“…ten thousand river commissions, with the mines of the world at their back, cannot tame that lawless stream, cannot curb it or define it, cannot say to it ‘Go here,’ or ‘Go there,’ and make it obey; cannot save a shore which it has sentenced, cannot bar its path with an obstruction which it will not tear down, dance over, and laugh at.”

–Mark Twain, Life on the Mississippi Rivers

What’s wrong with this stream? Part I described the vast extent of alteration and degradation of streams and rivers in the U.S. and the challenge this creates for stream mitigation.  In recent years the science of successful wetland restoration and mitigation has used the concept of reference – that is finding a high quality wetland and using it as a blueprint for restoring or creating a similar wetland – as one of the major strategies for assessing wetland health and for designing appropriate mitigation for wetlands lost or altered through permitting.  Reference is also being used to assess stream health in many states including Idaho and Kansas. It is also being applied in the context of stream mitigation.

But What If There Are No Reference Streams? This problem was raised recently in a stream restoration class I attended with Dr. Art Payola of the University of Louisville who made a statement I initially found astonishing.  There were no reference streams in the entire state of Kentucky.  The cumulative impact of forestry, mining and farming had altered every single river and stream.   Hmmm. I wondered if others agreed.   A week later I asked Mike Kline, State Rivers Program Manager in Vermont if it was difficult to find a reference stream in Vermont.  He laughed.  He’d challenged his staff for years to find a high quality reference stream.  They might have found three or four in the entire state, he said.  Recently I brought up the problem with a  DNR staffer in Missouri.  He was unsurprised by the question and suspected that there were no high quality reference streams remaining in the state.  As I pointed out in Part I, many of these altered streams look natural and are beautiful. But if they are degraded, then using them as a reference will only succeed at best in sustaining degraded streams.

Art’s class was pretty thought provoking.  Like many stream restoration professionals he had natural stream design training (Rosgen) and integrated it with other training, research and observation to come up with new ideas, concepts and methods for restoring streams.  Here are some of the elements of the training including visits to stream restoration sites that I found extremely interesting.

  1. Art is restoring streams for the 100 year flood consistent with the premise posited by Luna Leopold that streams are formed by the flood of record rather than frequent and much smaller bankfull events.
  2. The designs reconnect streams with both floodplains and ground water often by installing groundwater dams, submerged or buried timber and other methods.
  3. The restoration projects are designed to accrete carbon.  If possible, they are also designed so that the flood of record will not remove large amounts of sediment, rocks, etc. from the restoration site.
  4. The designs include establishment of numerous small sloping wetlands in the floodplain adjacent to the stream.
  5. There were no mosquitoes at the project sites.  This is my personal observation. On the first visit to one of a half-dozen restoration sites everyone covered themselves in bug spray.  It was June.  It was wet. It was hot.  It was also the last time we used bug dope for the duration of the class.  I can only surmise that the restoration project provided great habitat for mosquito predators.
  6. There were lots of frogs and salamanders and other small fauna.   For example we found a pocket wetland fed by groundwater at one site that was filled with spotted salamander nymphs.
  7. When completed these restoration projects stabilize the stream, provide improved groundwater storage, reconnect a stream with its floodplain, display prolific and abundant stream/wetland flora, provide refugia during storms and high-water for small fauna that are no longer washed away with every “bankfull” event.
  8. The restoration sites we visited, particularly the most recent ones resembled what one might expect to find on the site of a long abandoned beaver dam: a smallstream seeping through and around vegetation with pocket wetlands and a few old dead trees standing.

However, as exciting as this work is, there are some challenges.

  1. There is still much research needed
  2. Without reference, it will be essential to identify clear performance standards
  3. It is expensive
  4. It often requires removal of a lot of trees and may look radically different from the original site, particularly during construction.

What is apparent is that stream restoration and mitigation are evolving rapidly and hydrogeomorphologists, engineers, biologists, and a host of others are making enormous strides in understanding what is needed to restore streams.  A stream/wetlands complex such as the ones I saw during the training have the potential to  provide more stable streams reducing erosion, hold flood waters, providing aquifer recharge and creating greatly improved aquatic habitat.

And who knows—they might even help with climate change!

What Role Do Beavers Play in Climate Change

High Carbon Dioxide Spurs Wetlands to Absorb More Carbon

For More Information

Sustain – a journal of environmental and sustainability issues: River Restoration

Natural Stream Channel Design (Rosgen)

How Well Do the Rosgen Classification and Associated “Natural Channel Design” Methods Integrate and Quantify Fluvial Processes and Channel Response?

Restoration WARSSS

River Restoration Reference Materials

Applying Natural Channel Design Philosophy to the Restoration of Inland Native Fish Habitat

Stream Mechanics: Restoring Stream Ecosystems

River Restoration, Mountain-Prairie Region, Partners for Wildlife

River Restoration Reference Materials

More Reference Materials

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