Although billions of dollars have been invested in stream
restoration projects to replace lost and degraded fish habitat across the
United States since 1990, there is a lack of evidence that the projects have
actually benefitted salmon and steelhead, according to a recent study published
The authors of the study have an answer to this paucity of
information: intensively monitored watersheds.
Some 17 watersheds throughout the Northwest, nine in the
Columbia River basin, are already providing detailed and long-term insights
into how investments in stream restoration – projects such as placing woody
debris in streams or reconnecting habitat – are increasing smolt populations and
“All IMWs are experiments that are trying to answer the
basic question ‘is restoration of stream and estuary habitat working?’” said
lead author Stephen Bennett, research scientist, Watershed Sciences Department,
Utah State University in Logan, UT.
“By ‘working’ we mean is restoration resulting in an
increase in salmon and steelhead productivity in freshwater habitats,” he said.
“Although 100’s of millions of dollars have been spent restoring stream habitat
in (the Pacific Northwest), we do not have much data to support that more fish
are being created.”
"This (IMWs) is the best method we have for
understanding if restoration improves watershed scale productivity, how well it
works, and how we can get better at it," Bennett said.
According to information from NOAA Fisheries, IMW streams
have systems to track salmon and steelhead from emergence at the fry stage to
when the fish return as adults. In some cases, NOAA said, antennas are buried
in stream bottoms to detect PIT-Tags in fish as they leave and return,
documenting how many of the fish use the restored habitat.
The information in the IMW stream is compared with separate
control streams that have not had restoration projects.
The study, “Progress and Challenges of Testing the
Effectiveness of Stream Restoration in the Pacific Northwest Using Intensively
Monitored Watersheds,” was published online January 28, 2016, in the journal Fisheries, the monthly journal of the
American Fisheries Society, http://www.tandfonline.com/doi/full/10.1080/03632415.2015.1127805
For additional information about IMWs, including a case
study and data accompanying the article, go to http://www.pnamp.org/imw/home. AFS is
granting free access to the information through February.
In addition to Bennett, authors are: George Pess,
supervisory research fishery biologist, Chris Jordan, program manager, and
Correigh Greene, research biologist, Northwest Fisheries Science Center, NOAA,
Seattle, WA; Nicolaas Bouwes, aquatic ecologist, Eco Logical Research Inc.,
Providence, UT; Phil Roni, principal scientist, Cramer Fish Sciences,
Sammamish, WA; Robert E. Bilby, senior science advisor, Weyerhaeuser Co.,
Federal Way, WA; Sean Gallagher, senior environmental scientist, California
Department of Fish and Wildlife, Fort Bragg, CA; Jim Ruzycki, Mid-Columbia
Program Manager, Oregon Department of Fish & Wildlife, La Grande, OR; Thomas
Buehrens, research scientist, Washington Department of Fish & Wildlife,
Vancouver, WA; Kirk Krueger, senior research scientist, and Joseph Anderson,
senior research scientist, WDFW, Olympia, WA; William Ehinger, freshwater
ecologist, Washington Department of Ecology, Lacey, WA; and Brett Bowersox,
fisheries staff biologist, Idaho Department of Fish and Game, Lewiston, ID.
Simply implementing restoration and then monitoring the fish
and habitat does not constitute an IMW, according to the study. The study says
an intensively monitored watershed is “an experiment that uses a management
action (restoration) as a treatment and intensive monitoring to detect whether
a watershed-scale fish response to that action occurred.” The intensive
monitoring is well-suited to adaptive management, the study adds.
The goals of such an approach are to determine the
effectiveness of restoration actions at increasing salmon and steelhead
productivity; determine why fish respond to the habitat improvements; and,
ultimately, to replicate the results in other watersheds “where intensive
monitoring is not possible due to limited budgets,” the study says.
And, yes, it can be expensive. Bennett said he does not know
the cost of all IMWs, although the Asotin Creek IMW in the Columbia River
basin, which he works on, has an annual operating budget of $200,000 and others
could cost as much as twice that amount.
And, it will take time to determine the benefits of habitat
restoration projects, the study says.
"We're looking for a long-term response to restoration
from an animal that can vary widely from year to year," said NOAA
Fisheries’ Pess. He assisted with an IMW that tracked the return of salmon to
Washington's Elwha River following the removal of two Elwa River dams in 2011.
"You need sufficient time and detail to be able to say,
yes, the fish are increasing and, yes, it's because of the improvements in the
habitat," he said.
According to the study, of the 17 IMWs, nine are in
Washington, four are in Oregon. Nine of the IMWs are in the Columbia River
basin. Among the IMWs in the Columbia River basin are the Entiat and Methow
rivers in Washington’s upper Columbia basin, the Lemhi and Potlatch rivers in
Idaho, the lower Columbia River (Mill, German and Abernathy creeks) and the
IMWs are currently evaluating some seven common restoration
actions across four states and eight ecoregions. The most common (13) is
instream placement of woody debris, followed by habitat reconnection/improved
access to tributary and floodplain habitats (8), and barrier removal (5).
Multiple restoration actions are occurring in 12 IMWs.
Some of the results already confirmed for IMW restoration
-- a 250 percent increase in numbers of juvenile fish in
areas of Asotin Creek in Washington with restored habitat compared to those
--juvenile coho salmon survival in the Alsea River in Oregon
increased 50 percent in summer and 300 percent in the winter after restoration
improved rearing habitat.
--when posts were installed on Bridge Creek, a tributary of
the John Day River, in order to help beavers construct dams to reduce erosion
and boost the water table, the
production of juvenile steelhead increased 175 percent.
--reconnection of side channels expanded available habitat
on the Methow River in Washington and fish numbers increased 400 percent to 800
--scientists have thought that coho salmon that migrate to
the ocean in the fall of their first year do not survive, but IMW studies have
revealed that the fall fish may be important contributors to adult returns,
demonstrating that such diversity may be important to the long-term resilience
of these fish.
When establishing IMWs, the authors recommend establishing
an adaptive management framework ahead of time.
“It should be clear from the onset that the priorities of
the IMW should be to test the effectiveness of restoration actions at the
appropriate scale and to identify the causal mechanisms of the observed
responses where possible,” the study says. Long-term funding is necessary to
quantify the response because “it will likely take years to decades for such
responses to unfold.”
“These long term experiments are the best and arguably only
way to definitively determine if restoration is working - and we will learn a
lot about fish populations and watershed function in the process of conducting
these experiments,” Bennett said. “But people (funding agencies, the public)
need to be patient – watershed-scale experiments are complicated, fish
populations are difficult to study (due to high natural variability) – it will
take 10 to 20 years of careful monitoring to answer the question ‘is
-- CBB, Sept. 4, 2015, “Study: Habitat Restoration Projects
Often Fail To Target Highest Priority Needs For Ecosystem, Salmon” http://www.cbbulletin.com/434882.aspx
-- CBB, April 3, 2015, “Producing Salmon: Study Looks At
Cost Effectiveness Of Habitat Restoration Compared To Hatcheries” http://www.cbbulletin.com/433567.aspx
-- CBB, Nov. 7, 2014, “Adding Wood Structures To Streams
Promotes Fish Recovery, But Do They Have To Cost So Much?” http://www.cbbulletin.com/432582.aspx