A group of Idaho fisheries conservation
leaders has developed a new approach toward evaluating and prescribing
effective habitat restoration measures for salmon and steelhead in the upper
Salmon River Basin, with potential for the approach to be applied elsewhere.
The group made a presentation to the Northwest
Power and Conservation Council at its November meeting in Coeur d’ Alene,
Idaho, explaining the Upper Salmon Integrated Rehabilitation Assessment
Salmon recovery throughout the Columbia Basin
has often been framed in the classic “Four-H” context — hatcheries, harvest,
hydro system and habitat — with success being measured by a Smolt-to-Adult
Return rate (SAR).
But the presenters say only improved tributary
habitat sustainability increases the number of juveniles entering the hydro
system in a manner that can provide long-term advances toward regional salmon
In the Upper Salmon River and its tributaries,
for instance, there is evidence of adequate egg and fry production, and the
existing habitat is passable for adult fish returning to their spawning waters.
But there is a life-cycle bottleneck in the habitat’s ability to support young
fish as they develop into smolts.
“Unfortunately, there are few examples of
freshwater habitat improvements that are accompanied by quantitative evidence
that allow their value to be placed in the context of the SAR equation,” states
materials provided by the group.
“The reality is availability of funding in the
Columbia Basin is changing. We’ve been informed by Bonneville that there’s a
lot of pressure from the revenue standpoint,” said Mike Edmondson, program manager for the Governor’s Office of
Species Conservation. “We have to be efficient. We have to be effective,
and if we can’t prove that the actions that we are proposing will be efficient
and effective then it will be even more difficult (to get funding).”
The Upper Salmon IRA uses a new metric,
measuring habitat “capacity,” or its ability to support the conversion of
spring and summer chinook smolts entering the hydro system.
“The IRA differs because we let the biology
determine what kind of habitat actions to take through several life stages to
ultimately get the number of healthy fish emigrating in the spring,” explained
The approach has been applied using regional
goals for salmon recovery, providing targets for freshwater capacity
requirements that will provide meaningful results. Past habitat assessments,
including CHaMP, have provided valuable, near-encyclopedic data on physical
conditions of rivers and streams, but the IRA approach is more targeted and
should provide measurable results when implemented at the project level, the
“It integrates biology with geomorphology
where it is most practical,” Edmondson told the council. “We wanted a process
where the biology drove the bus.”
The IRA process attempts to address questions
such as what types of rehabilitation work are needed, where is it needed, and
just how much work is necessary to produce results.
As examples, the IRA approach has identified
stream stretches in the Upper Salmon Basin that are much wider and shallower
than they used to be, with adverse effects on rearing habitat, and it has
revealed that improving rearing habitat near spawning beds called redds would
be far more effective than pursuing rearing habitat far downstream. Or, it was
noted, there may not be a need to invest in measures to improve redd capacity
that is already adequate.
“Historically, reproduction was occurring
farther up in the basin,” Edmondson said. “They had more rearing capacity.”
Since life cycles also have seasonal
dimensions, it may be that improvements to streams as they are in the winter
may also be highly effective in improving smolt development and survival,
Edmondson said, noting that a thorough look at winter habitat capacity is the
next stage of developing the Upper Salmon IRA, as recommended by an Independent
Scientific Review Panel in 2013.
As habitats are strategically implemented, or
“stacked,” throughout a drainage the results are expected to provide measurable
advances toward recovery goals, Edmondson explained.
“We could get to at least recovery levels, and
probably beyond recovery levels,” Edmondson said.
Jude Trapani, a representative of the Bureau
of Reclamation involved with developing the process, told the council that “We
can do this with just about any drainage in the Columbia River system. The
confidence levels are very similar.”
Mark Davidson, a representative of the Nature
Conservancy, pointed out that the IRA process should yield project proposals
that have more specificity than broader, shot gun approaches to habitat
restoration. That can be very valuable in approaching landowners whose
cooperation is needed for many projects to proceed, he said.