**The Watershed Program Research Plan**

**Northwest Fisheries Science Center**

**Environmental Conservation Division**

**National Marine Fisheries Service**

**2725 Montlake Blvd. E.**

**Seattle, WA 98112**

**Mission**

> The Watershed Program conducts research on physical and biological
> processes that influence aquatic ecosystems in the Pacific Northwest,
> effects of land management on those ecosystems, and ensuing effects on
> the health and productivity of anadromous fish populations. Program
> scientists provide technical support to National Marine Fisheries
> Service (NMFS) policy makers and regulatory staff, and collaborate
> with other agencies, tribes, and educational institutions on research
> and education related to the management of Pacific salmon
> (*Oncorhynchus* spp.).
>
> **Program Description**

The Watershed Program staff includes scientists with skills in fish
biology, aquatic and riparian ecology, geomorphology, hydrology,
chemistry, spatial analysis, and statistics. Our research focuses on
natural processes that form and maintain aquatic ecosystems, and on land
uses and restoration actions that can alter these ecosystems and affect
salmon populations. We link land uses to habitat conditions by examining
the processes that form and sustain riparian, riverine, and estuarine
environments, including such processes as the routing of sediment,
water, and organic material from hillslopes and riparian areas to
streams. All of our research is ultimately related to the health and
productivity of anadromous fish populations, as we seek to understand
how watershed condition affects aquatic ecosystems, habitat conditions,
and fish communities.

Our research findings are used by NMFS and other natural resources
managers to develop actions and policies that protect and recover
aquatic ecosystems and salmon populations. The Watershed Program also
provides NMFS policy makers and regulatory staff with scientific
information and assists in evaluating the consequences of proposed
management actions. In addition to conducting scientific research,
Watershed Program scientists hold affiliate faculty positions at
University of Washington, University of British Columbia, and Seattle
University. Watershed Program scientists also hold positions on the
Center for Streamside Studies advisory board and work on interagency
technical teams.

**Program** **Research**

The Watershed Program focuses on three primary research themes:

1)  quantify fish responses to changes in watershed, habitat, or
    ecosystem conditions,

2)  quantify the effects of natural or human disturbance on watershed
    processes and habitat conditions, and

3)  evaluate the effectiveness of various habitat and watershed
    restoration strategies or techniques.

The first theme responds to the lack of comprehensive habitat-based
production models for most salmonids. Without such models we cannot
predict population responses to watershed or habitat changes (including
restoration actions). The second theme addresses the continuing need to
quantify how land uses affect watershed processes and aquatic habitats,
and ultimately alter salmonid production. Similarly, the effectiveness
of various restoration strategies and techniques (the third theme) must
be evaluated to understand how each approach affects watershed
processes, aquatic habitat, and salmonid abundance and survival.

*Research approach*

Watershed Program research is organized around a conceptual model of
watershed function (Figure 1). In this model, habitat conditions in
streams and estuaries link landscape and land use characteristics to
fish abundance and survival. We distinguish between research on
habitat-forming processes and habitat-based fish production models so
that we can study habitat processes that influence riverine and
estuarine ecosystems independent from the species that use those
habitats. We can then relate abundance, growth, fitness, and survival of
any species to this single suite of habitat or ecosystem metrics.
Program research often spans all segments of the conceptual model, and
this larger picture clarifies relationships between our various research
activities.

Landscape and ecosystem processes operate at a wide variety of space and
time scales (Figure 2). Therefore, we recognize that spatial and
temporal scales of assessment vary depending on the relationships under
study. For example, we might use coarse resolution remote sensing data
to investigate broad regional patterns in relationships among geologic
or climatic variables and ecosystem conditions or salmon populations. By
contrast, we use detailed field data to investigate how different
riparian buffer treatments affect light regimes and primary productivity
in specific stream reaches. As a general rule, insights gained from
larger scale assessments lead to investigation of specific cause and
effect linkages at smaller spatial scales.

With this research structure the Watershed Program can strategically
address research topics that are important in the near term, and
initiate key in-depth studies that will provide answers to difficult
questions in the long term. By maintaining process-based linkages
between research elements, we can more cost-effectively integrate
results into a comprehensive understanding of watershed and ecosystem
function, which ultimately will allow NMFS to better administer habitat
protection under the Endangered Species Act (ESA) and the essential fish
habitat (EFH) component of the Magnuson-Stevens Fishery Conservation and
Management Act. For near-term ESA recovery planning (e.g., Technical
Recovery Teams), we also use this conceptual model to help identify
appropriate simplifying assumptions that can answer management needs
sooner. Simpler models such as the salmonid watershed analysis model
(SWAM) allow us to estimate answers to specific management questions
quicker than through the more detailed studies in our research plan.

![](media/image1.png){width="3.095833333333333in"
height="3.870138888888889in"}

Figure 1. Schematic diagram of relationships between landscape and land
use controls on habitat characteristics (via habitat forming processes),
and between habitat characteristics and salmon fitness and survival.

![](media/image2.png){width="3.0965277777777778in"
height="1.9631944444444445in"}

Figure 2. Spatial and temporal scales of factors that control habitat
conditions and fish production in streams (adapted from Naiman et al.
1992).

*Research theme 1: quantify fish responses to changes in watershed,*
*habitat,* *or ecosystem conditions.*

In order to predict responses of fish populations to watershed and
habitat changes (ultimately what NMFS needs to conserve and recover
salmon populations), we must understand how fishes utilize stream and
estuary habitats. There are relatively few studies that quantify
abundance, survival, and fitness of salmonids in these habitats (coho
salmon *O. kisutch* are a well-studied exception), especially in large
rivers where chinook salmon (*O. tshawystcha*) and steelhead trout (*O.
mykiss*) are dominant species. Without such studies we are unable to
develop life-stage models to help us evaluate potential effects of
freshwater and estuarine habitat changes on most fish populations. Our
research plan includes formalizing the structure of life-stage models
for salmon, as well as collection of critical data required to
parameterize and run the models. Developing these models will allow us
to estimate responses of salmon populations to changes in watershed or
ecosystem conditions.

We will develop fish production models at a variety of scales to meet
different management needs. Landscape-scale models will illustrate broad
relationships among landscape characteristics, land use, and salmon
abundance. Such models can assist managers in locating areas with
relatively high potential abundance and areas with relatively high
restoration potential. However, they do not indicate which restoration
actions are needed, or how different restoration actions will affect
salmon populations. More detailed life-stage models for salmonids will
provide greater insight into the effects of specific habitat changes and
restoration actions. These models are based on extensive field data of
fish use and survival in different habitat types, and under different
ecosystem conditions or management regimes. Where possible, we will use
experiments to clarify the results of our field studies, and to gain
greater resolution on the degree to which different habitat or ecosystem
characteristics affect anadromous fish populations.

### Research theme 2: quantify the effects of natural and human disturbance on watershed processes and habitat conditions.

Immutable landscape variables (e.g., geology, valley form, and drainage
network configuration) are unaffected by land use practices. They
determine the range of potential habitat conditions that a specific site
can exhibit, the underlying physical potential of different locations
within and among watersheds. Mutable landscape and land use variables
(e.g., riparian forest modification, increased landsliding) then
determine the habitat characteristics expressed at a site at any point
in time. Understanding these relationships is a critical step in
understanding the "habitat potential" of different areas, which can be
used to help identify areas where habitat protection or restoration are
most likely to provide significant benefits for salmon production.

At the river basin scale ([\>]{.underline}10^4^ km^2^) we rely primarily
on analysis of relationships among underlying landscape characteristics,
existing management regimes, and habitat conditions. Coarse resolution
geospatial data sets are adequate for determining large-scale influences
of such factors as geology, landforms, precipitation regimes, and land
use practices on stream and river habitats and food webs. At the reach
scale we require field data in order to accurately assess influences of
such factors as valley form, channel morphology, riparian management
regime, and water quality on physical and biological processes, and
habitat characteristics. Manipulative experiments to isolate effects of
individual landscape or land use characteristics on specific aspects of
stream habitat or productivity are more feasible at the reach scale
(\~10^2^ m). These experiments will help resolve ambiguities emerging
from our analyses at the river basin scale.

#### *Research theme 3:evaluate the effectiveness of watershed and habitat restoration strategies and techniques.*

Many approaches and techniques for restoring salmon habitats are used in
watershed management plans or as components of a salmon recovery
strategy. However, it is often unclear how watershed-level or
site-specific restoration actions might contribute to recovery of salmon
stocks. This stems in part from limited information on the effectiveness
of various habitat restoration and enhancement techniques.
Unfortunately, few watershed and stream habitat restoration techniques
(e.g., instream structure placement, riparian planting, road
restoration, reconnection of isolated habitats, etc.) have been
adequately evaluated, and there is considerable debate within the
scientific community about the effectiveness of various techniques.
Drawing statistically significant conclusions about the biological
effectiveness of various techniques has been difficult, and this has
hampered efforts to provide scientific guidance on restoration
activities.

Despite these limitations, we have a reasonable understanding of the
processes that affect channel morphology and create fish habitat. For
example, in the coastal Pacific Northwest, the delivery of organic
matter (e.g., woody debris, leaf litter, etc.), water, and sediment are
major processes dictating channel morphology and the formation of salmon
habitat. In the 1990s, it became widely accepted that restoring such
watershed processes is the key to restoring watershed health and
improving fish habitat, and many studies have described restoration
strategies that emphasize on restoring these physical and biological
processes. However, such strategies (e.g., road restoration, culvert
removal, riparian and upslope restoration) occur at the site or reach
level and a method that places site-specific restoration within a
watershed context is needed to assist in prioritizing and implementing
restoration.

We are and will continue to work collaboratively with other agencies to
conduct and monitor watershed-wide experiments where specific land use
practices are altered in an attempt to improve watershed processes,
habitat characteristics, or water quality. By carefully managing the
application of restoration actions (e.g., making sure that road
restoration is focused so that we have control and treatment
watersheds), we can evaluate the effectiveness of techniques for
restoring habitat conditions, water quality, or fish populations. These
results will help identify:

1)  which types of restoration actions are effective at restoring salmon
    habitats and contributing to recovery of salmon populations, and

2)  where restoration actions will have the greatest long-term benefits
    for salmon populations.

The information gained in understanding salmonid responses to
restoration actions will inform the previous two research themes. That
is, restoration actions can be treated as experimental manipulations of
land uses or habitat characteristics, which can improve our
understanding of the linkages among watershed process, aquatic ecosystem
conditions, and salmon abundance and survival.

##### 

#####  {#section-1 .unnumbered}

#####  {#section-2 .unnumbered}

##### Research Teams

The Watershed Program is organized into three research teams, each
focusing on one of the three key research themes. The three teams are:

1)  Fish and Habitat Relationships Team

2)  Watershed Processes and Human Disturbance Team

3)  Restoration Team

Each team has identified high priority research objectives (questions)
to help coordinate future research efforts, and build off our existing
research. Following are the research objectives and future research
areas for each team.

####### **Fish and habitat relationships** **team**

Successful management of Pacific salmon in the Pacific Northwest and
recovery of listed species depends in part on our ability to quantify
the effects of land uses on habitat and salmon populations, as well as
the benefits of restoration activities on salmon survival and fitness.
Our research approaches this problem along two main avenues. First,
regional assessments of landscape and land use effects on salmonid
populations will be used to evaluate correlations among landscape and
land use attributes and fish population responses. These studies
establish linkages between land uses and population responses. The
development of such linkages is an important component of technical
recovery planning efforts.

Second, detailed life-cycle modeling will advance our ability to predict
population responses to habitat change. These models will provide
scientific and data-based tools for evaluating the likely outcomes of
changes in land use practices or of salmon habitat restoration efforts
in the region. Because each model is driven by habitat condition (both
amount and quality), we will be able to link our watershed process
studies to instream habitat conditions and to fish population
performance. Moreover, construction of such a model will help us
evaluate a wide range of management scenarios because it relies on
understanding the fundamental processes linking aquatic habitats to
salmon populations.

Our field research over the next five years will focus on estimating the
habitat capacity and survival for each life stage of ESA listed chinook
salmon. A number of cooperative studies are near completion or in
progress, including effects of flooding on freshwater survival, effects
of riprap on use of mainstem river habitats by juveniles, and use of
estuary habitat types by juveniles. Each provides answers to questions
of immediate concern, as well as crucial data for development of the
life-cycle model. Future studies must include the more detailed and
difficult studies required to estimate survival in rivers and estuaries
as a function of habitat type and quality. Near-term research objectives
include the following:

1.  *Broad-scale relationships among land uses and fish populations*.
    Regional salmon recovery planning efforts require the ability to
    rapidly evaluate impacts of various land uses on salmon habitat and
    populations across entire Evolutionarily Significant Units (ESUs).
    Two main factors inhibit detailed analyses across such large areas:
    field data on habitats and populations are not available across the
    region, and mechanisms linking land uses to populations effects are
    not well understood. An alternative approach is to systematically
    assess correlations among landscape or land use attributes and fish
    populations (e.g., SWAM). These studies help identify major land use
    factors affecting salmon populations and quantify uncertainties in
    the relationships.

2.  *Development of a habitat-based salmon life-cycle model.* We will
    develop a life-cycle model that can integrate effects of different
    habitat changes on salmon populations. This model will be
    habitat-based and will have a relatively simple structure (Figure
    3). We have three research goals for development of this initial
    model. First, produce a life-cycle model for Puget Sound chinook
    salmon that can form the basis for future efforts. This model will
    be adequate for first approximations of effects of habitat change on
    chinook

![](media/image3.jpeg){width="3.1590277777777778in"
height="3.0305555555555554in"}

> Figure 3. Schematic diagram of the simplified salmon life-cycle model.

populations. Second, collect and analyze field data needed to
parameterize and update this model, including estimates of survival from
life stage to life stage. These updates will increase reliability of the
basic model. Third, design additional model elements that incorporate
biological processes and life-history patterns. At each step we will
evaluate whether increasing the complexity of the model results in
increased accuracy or sensitivity.

3.  *Quantifying stage-to-stage survivals for salmonids in freshwater
    and estuaries*. This is the greatest data gap in virtually all
    salmon modeling efforts at present (with the possible exception of
    coho salmon). This task may require adaptation or development of
    marking techniques for small juvenile salmon, evaluations of
    statistical methods suitable for estimating survival rates, studies
    of migration patterns and cues at different life stages, and
    potential refinement of capture techniques.

4.  

5.  

6.  *Influence of spatial structure (habitat and population) on
    population responses to habitat change*. We are initially concerned
    with three aspects of habitat use by salmonids and their effects on
    population dynamics: spatial structure of salmon populations and
    their habitats, habitat-specific density dependence, and habitat
    selection by salmon. Initial investigations will employ a
    combination of life-cycle modeling and field data. Field studies and
    experiments will later be required to understand mechanisms and
    processes that explain observed patterns and their effects on the
    dynamics of salmon populations.

7.  *Effects of changes in habitat quality on salmonid abundance and
    survival*. Research will focus on effects of changes in habitat
    quality (e.g., stream productivity, stream temperature) on salmonid
    abundance and survival. Studies will include research on sub lethal
    effects and delayed mortality. Field studies and experiments to
    systematically address influences of productivity and stream food
    web structure on growth and survival of salmonids are currently
    underway*.*

8.  *Climate change effects.* Models of global climate change predict
    lower precipitation and higher temperature regimes in the Pacific
    Northwest, and therefore higher stream temperatures and increased
    freshwater eutrophication. As these influences can have significant
    effects on Pacific salmon and their competitors, we will initiate
    studies to evaluate impacts of large-scale environmental change on
    the long-term performance of salmon populations.

9.  

10. 

11. 7\. *Analysis of fish density data.* Nearly all studies of habitat
    use by salmonids require analysis of data on fish density. These
    data often have a random denominator (e.g., pool area) as well as a
    random numerator (e.g., number of fish). In addition, there are
    often many more zero observations than one might expect for common
    statistical distributions. Interpretation of such data requires
    careful consideration of underlying assumptions. Research is
    underway to assess the best methods of analyzing fish density data
    and the implications of a range of biological and ecological
    assumptions.

###### **Ecosystem** **processes and human disturbance** **team**

The Pacific Northwest is a highly dynamic landscape where natural
processes such as debris flows, floodplain development, and organic
matter export vary in space and time. Pacific salmon adapted to and
thrived in this landscape. However, land use activities such as logging,
farming, and urban development have significantly affected these
processes. As a result, a large proportion of the freshwater habitat
that Pacific salmon depend upon is degraded. Little is known, however,
regarding how natural processes affect the formation and maintenance of
salmonid habitat, and ultimately the distribution, abundance, growth and
survival of Pacific salmon. We also know little about how subsystems
within a watershed interact, effect downstream reaches, or the
cumulative effects of various activities throughout watershed or basin.

-   

-   

-   

-   

-   

-   Our research focuses on understanding how natural processes within a
    watershed (from headwaters to nearshore) affect the formation of
    salmonid habitat, the growth and survival of Pacific salmon, and how
    land use activities affect these response variables. We will link
    our research directly with the life cycle model being developed by
    the Fish and Habitat Relationships Team. Specifically, the life
    cycle model will provide hypotheses for subsequent studies by our
    team, the results of which will then be used to further refine
    models. Hence, we envision a tight coupling between field studies,
    experiments, and mathematical models. This approach will allow us to
    develop tools to evaluate and predict the effects of different land
    uses on habitat, productivity, and ultimately biota.

We have several ongoing projects including: examining riparian buffers,
landscape attributes of riparian vegetation and ecosystem function,
timber harvest and stream functionality, effects of urbanization on
nearshore and estuarine conditions and biota, function of headwater
streams, and effects of floodplain development on physical and
biological characteristics of rivers. In addition to these studies, over
the next five years, we will focus on the following key research
questions:

1.  *Watershed*-*scale management practices*. Cumulative effects of
    multiple land use practices within a watershed impact streams in
    different ways, depending on the type, frequency, and spatial
    distribution of such activities. By analyzing watershed patterns of
    land use (e.g., road density, forest age distribution) and patterns
    of natural features (e.g., geology, geomorphology, precipitation)
    and comparing them with stream habitat conditions, we can gain
    insights into the types of spatial and temporal patterns of land use
    activities that are compatible with high quality conditions.

2.  *Urban stream systems*. Perhaps nowhere are the natural processes
    that contribute to the formation of freshwater habitat disrupted
    more profoundly and irrevocably than in urban basins where forested
    landscapes are replaced with roads, rooftops, and other impervious
    surfaces. Despite the fact that urban sprawl is increasing across
    the Pacific Northwest, there has been very little study of urban
    streams from an ecological perspective. In order to craft effective
    restoration and conservation strategies, we need greater knowledge
    of what species (native and non-native) live in these systems, how
    they interact within the heavily modified stream environment, and
    how biota respond to urbanization and the specific stressors that
    accompany such change. In particular, two arenas in which greater
    research would be particularly valuable are the role of riparian
    corridors in urban landscapes and the relationships between
    biological indicators of stream health and specific measures of
    habitat alteration. This will be linked to our ongoing research
    examining the effects of urbanization on estuarine and nearshore
    habitats.

3.  *Lowland river ecology*. Most of the research on stream salmonids
    has occurred in relatively high elevation forested watersheds. In
    contrast, little is known about how natural processes affect habitat
    formation and salmonids in lowland river reaches. This discrepancy
    is problematic, as most fish production occurs in low elevation
    rivers. In addition, these regions are impacted by a variety of land
    uses (primarily agricultural and urban), and very little is known
    about the impacts of farming or urbanization on natural processes.
    For this research, we will begin to collect baseline information on
    natural processes, habitat, and salmonids in large river systems
    areas in relatively pristine areas and on lands impacted by land
    uses. We are initiating several projects to investigate large river
    processes, including the transport of nitrogen from farms into
    surface waters, morphological controls on the dynamics of floodplain
    ecosystems, and food web dynamics associated with logjams.

4.  *Influence of nutrients and light on stream food webs and salmonid
    growth and survival and how habitat interacts with basal resources
    to affect stream salmonids*. Although much is known regarding
    physical habitat and fish abundance, there is relatively little
    known about how nutrients or light regime affect salmon populations
    or how these abiotic resources interact with habitat to affect
    salmonids. In this research, we will use a combination of natural
    gradients (e.g., gradients in nitrogen concentration in natural
    streams), field experiments, and mesocosm experiments to examine how
    resources and habitat interact to affect the growth and survival of
    stream salmonids. We will use models developed by the Ffish and
    H/habitat Relationships Tteam to help in formulation of hypotheses;
    the design of these experiments; the types of data to collect; and
    interpretation of results. Similarly, we will work with the
    Restoration Team to examine how addition of organic and inorganic
    nutrients, such as salmon carcasses can alter stream productivity.
    Data from these studies can then be used to further refine life
    cycle models developed by the Fish and Habitat Relations
    Teamfish/habitat team. Existing studies include examining how
    riparian buffers affect stream ecosystems, and landscape attributes
    of riparian vegetation and stream ecosystem structure and function.

5.  

6.  

7.  

8.  *Linkages between physical and biological diversity*. In the Pacific
    Northwest, salmon have adapted to a highly dynamic landscape where
    stochastic processes form and sustain their habitats. However, these
    processes and their effects on biological diversity are poorly
    understood. For example, recent studies have shown that mainstem
    habitat is more diverse (e.g., higher substrate heterogeneity)
    downstream of tributary junctions compared to upstream. Biological
    diversity can also be higher downstream of these junctions, as a
    result of higher physical diversity. However, land use activities
    such as logging, farming, and urban development have significantly
    affected these linkages. This research area will systematically
    examine linkages between physical diversity, biological diversity,
    and fish production, and how land use alters these linkages.

The goal of each of these five research areas is to advance our
understanding of linkages among natural processes, habitat, and salmon
growth and survival. Although we know a tremendous amount about how
salmon use different types of habitat, we know almost nothing about the
mechanisms driving these patterns or how survival is related to habitat
quantity or quality. We also know very little about the natural rates of
variation in the processes that create, maintain, and ultimately degrade
stream habitat, or how long it takes for streams in degraded watersheds
to return to properly functioning conditions under various management
strategies. Hence, our long-term goal is to fill many of these gaps.

##### *Restoration Team*

Our research focuses on understanding how site-specific and
watershed-wide restoration actions affect watershed processes, stream
productivity, the formation and maintenance of habitat, and the growth
and survival of salmonids. We will link our research directly with the
life cycle model being developed by the Fish and Habitat Relationships
Team and the work done by the Ecosystem Processes and Human Disturbance
Team. This approach will allow us to evaluate the effects of different
restoration activities on stream productivity and salmonid response,
identify which types of restoration actions are effective, and where
restoration will have the greatest long-term benefits in salmon
production.

Our general goal is to identify how stream and salmonid productivity is
influenced by site-specific and watershed-scale habitat restoration
efforts. Currently, we have a number of key research projects ongoing
that address linkages between watershed restoration activities, stream
structure and function, and fish response. We will use the salmon life
cycle models developed by the Fish and Habitat Relationships Team in the
design of these projects. Biological data from preceding studies can be
used to help fill the gaps of knowledge in such life cycle models. Over
the next five years, we will continue to address these linkages and
focus on the following key research questions:

1\. *Small stream restoration: effects of wood and boulder placement*
*on primary productivity and fish* *in small streams.* The restoration
of freshwater habitat through the placement of wood and boulders has
become a common method for restoring salmon habitat. Unfortunately,
comprehensive evaluation of these projects is lacking. The objective of
this project is to evaluate the biotic res ponses to the placement of
wood and boulders in small streams in the Pacific Northwest. While our
ongoing studies have examined changes in abundance associated with
restoration activities, our future research will focus on examining the
effects of restoration on both fish movements and survival; the ultimate
measures of restoration effectiveness. These estimates of survival will
be used in the salmon life cycle models being developed by the Fish and
Habitat Relationships Team.

2\. *Restoration of large rivers:* *Influence of engineered logjams in
large rivers on primary productivity and fish response.* The restoration
of freshwater habitat in larger river systems through the placement of
large logjams is becoming a larger component of bank protection and
salmon habitat restoration efforts. We will evaluate how these large
logjams redistribute adult salmon, and how they affect juvenile salmon
use and growth rates, and macroinvertebrate response. Similar to the
project on small streams, we will also examine fish movements and
survival among in rivers with a and without engineered logjams.

3\. *Floodplain restoration:* *comparison of natural to constructed
floodplain channels.* The loss of important off-channel rearing habitat
in large and small alluvial rivers has lead to increased emphasis on
reconnecting isolated habitats and constructing off-channel ponds. The
objective of this project is to evaluate the effectiveness of
reconnected and artificially created off-channel ponds and assess their
contribution to basin-wide salmon production. This study in combination
with a study on floodplain dynamics will be used to develop
comprehensive guidelines for floodplain restoration.

4\. *Dam removal:* *effects of changing sediment supply on habitat
formation and biological response.* Despite long-standing concerns about
effects of increased sediment supplies on salmonid rearing habitats,
there have been no direct measurements of reach-level effects of altered
sediment supply on rearing habitat formation. Our study will capitalize
on alteration of sediment supply before and after removal of the Elwha
River dams in order to assess effects of changing sediment supplies on
rearing habitat. The study sites downstream of the dam include reaches
with and without wood in order to quantify the interactive effects of
sediment and wood on habitat formation.