NOAA Technical Memorandum NMFS-NWFSC-127

Fish-Habitat Relationships 

and the Effectiveness of 

Habitat Restoration

June 2014

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Northwest Fisheries Science Center
NOAA Technical Memorandum

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imply endorsement by the National Marine Fisheries Service.

Reference this document as follows:

Roni, P., G.R. Pess, T.J. Beechie, and K.M. Hanson. 2014. 

Fish-habitat relationships and the effectiveness of habitat 

restoration. U.S. Dept. Commer., NOAA Tech. Memo. 

NMFS-NWFSC-127.
NOAA Technical Memorandum NMFS-NWFSC-127

Fish-Habitat Relationships 

and the Effectiveness of 

Habitat Restoration

Philip Roni, George R. Pess, Timothy J. Beechie, 

and Karrie M. Hanson

Northwest Fisheries Science Center

Fish Ecology Division

Watershed Program

2725 Montlake Boulevard East

Seattle, Washington 98112

June 2014

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service
Most NOAA Technical Memorandums

NMFS-NWFSC are available at the 

Northwest Fisheries Science Center

Web site, http://www.nwfsc.noaa.gov

Copies are also available from the

National Technical Information Service

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Springfield, VA 22161

Phone orders: 1-800-553-6847

E-mail orders: orders@ntis.fedworld.gov

ii
Contents

List of Figures...............................................................................................................................................v

List of Tables..............................................................................................................................................vii

Executive Summary.....................................................................................................................................ix

Acknowledgments........................................................................................................................................xi

Introduction...................................................................................................................................................1

Fish-Habitat Relationships............................................................................................................................2

Impacts of Management Actions on Fish Habitat.........................................................................................5

Effectiveness of Common Restoration Techniques......................................................................................7

Literature Reviewed .................................................................................................................................7

Fish Passage..............................................................................................................................................9

Barrier Removal ...................................................................................................................................9

Entrainment..........................................................................................................................................9

Instream Structures.................................................................................................................................10

Off-Channel/Floodplain Habitat.............................................................................................................12

Reconnection......................................................................................................................................13

Levee Removal/Setback.....................................................................................................................13

Side Channel and Pond Construction.................................................................................................13

Channel Restoration ...........................................................................................................................14

Riparian Improvement............................................................................................................................14

Riparian Planting and Silviculture Treatment....................................................................................14

Riparian Fencing and Grazing............................................................................................................15

Invasive Species Removal..................................................................................................................15

Sediment Reduction................................................................................................................................15

Acquisition and Protection .....................................................................................................................16

Flow Augmentation ................................................................................................................................16

Studies Examining Survival ...................................................................................................................17

Restoration and Limiting Factors...........................................................................................................18

Project Implementation and Design........................................................................................................20

Restoration Effectiveness at the Population Level .................................................................................20

iii
What Can Models Tell Us about Population Responses?...........................................................................24

Stage-Specific Capacity Models.............................................................................................................24

Life Cycle Models..................................................................................................................................25

Summary and Conclusions .........................................................................................................................28

References...................................................................................................................................................29

Appendix A: Lists of All the Literature Examined with Summaries of Key Findings...............................41

Fish Passage/Barrier Removal References.............................................................................................41

Instream Structure References................................................................................................................46

Off-Channel/Floodplain Habitat References........................................................................................111

Riparian/Grazing References................................................................................................................130

Sediment/Road References...................................................................................................................141

Acquisition and Protection Reference ..................................................................................................147

Flow References...................................................................................................................................148

Appendix B: Subset of the Literature Examined that Reported on Survival ............................................151

iv
Figures

Figure 1. Mean increase in coho salmon, steelhead, and Chinook salmon smolts reported from 

different types of habitat improvement.......................................................................................................10

Figure 2. Percent of published studies evaluating instream habitat improvement that have 

shown an increase, small decrease, or no response of juvenile and adult salmon to placement 

of instream structures..................................................................................................................................11

Figure 3. Map of intensively monitored watersheds and Columbia Habitat Monitoring Program

pilot watersheds in the Columbia River basin ............................................................................................23

Figure 4. Estimated increases in juvenile Chinook salmon habitat carrying capacity, assuming 

an increase in habitat area and habitat quality by rehabilitation action in all reaches of 64 km of 

the Trinity River..........................................................................................................................................26

Figure 5. Estimated change in Chinook salmon population size with varying restoration scenarios 

and climate change......................................................................................................................................27

v
vi
Tables

Table 1. The Bonneville Power Administration Fish and Wildlife Program habitat 

improvement project categories and subcategories, and the number of published studies 

that examined this type of restoration...........................................................................................................8

Table 2. Limiting factors addressed by each restoration action type and subtype, and the 

strength of evidence in published literature that a particular action subcategory addresses 

a limiting factor or habitat impairment .......................................................................................................19

Table 3. Common factors to consider during project planning and design to increase success 

or effectiveness...........................................................................................................................................21

Table B-1. Key findings from a subset of papers on restoration effectiveness in Appendix A 

that reported survival or changes in survival due to restoration ...............................................................151

vii
viii
Executive Summary

A major underpinning of recovery efforts for Pacific salmon (Oncorhynchus spp.) listed 

under the Endangered Species Act is that there is a strong relationship between freshwater 

habitat quantity and quality and salmon abundance, survival, and productivity in the freshwater 

environment. This is a major component of Endangered Species Act recovery plans and 

biological opinions for salmon and steelhead (O. mykiss), including the 2008 Federal Columbia 

River Power System Biological Opinion (BiOp). With regard to habitat, the 2008 BiOp

incorporates an expanded tributary habitat program that requires implementation of habitat 

improvement actions, including actions to protect and improve mainstem and side channel 

habitat for fish migration, protect and improve spawning and rearing, and restore floodplain 

function. Because this is a key underpinning of the 2008 BiOp and other biological opinions, it 

is important to 1) document our understanding of the relationship between habitat quantity and 

quality and salmon production, 2) quantify the improvements in salmon production and survival 

that can be expected with different restoration actions, and 3) use models to help identify habitat 

factors limiting production and quantify population-level responses to restoration. This technical 

memorandum provides a synthesis of scientific literature and our current level of knowledge on 

these three topics.

Decades of fish-habitat relationship research have demonstrated the importance of 

freshwater and estuarine habitat for various life stages of Pacific salmon. Moreover, research has 

shown the negative impacts of human actions on habitat quality and localized salmon carrying 

capacity, growth, and life history diversity. More recently, efforts have been made to quantify 

the effectiveness of various restoration techniques. Many studies have reported improvements in 

physical habitat, particularly at a reach scale for various techniques. Fewer studies have 

quantified biological responses, but several have shown localized (reach scale) increases in fish 

abundance for placement of instream structures and reconnection of both tributary and floodplain 

habitats. Also, few of these studies have explicitly examined changes in salmon or steelhead 

survival. Less information exists for other techniques and additional research is needed to 

quantify changes in fish survival and abundance due to restoration at reach and watershed scales.

Extrapolating these reach-scale effects up to the watershed or population scale requires 

either watershed-level or population-level evaluation or salmon life cycle modeling. Several 

intensively monitored watershed studies are currently underway to quantify population-level 

survival and production responses to multiple restoration actions throughout a watershed. Initial 

results from these studies are promising; however, results will not be available for most of these 

studies for 5 or more years and results may not be directly transferable to other populations and 

watersheds. Until these studies are completed, predicting population-level responses to habitat 

change can be estimated with statistical/computer models. These include two general categories: 

1) limiting-factors models based on stage-specific habitat capacity and 2) life cycle models that 

account for survival and abundance at each life stage. While modeling approaches are useful, 

there is much uncertainty in all models, and quantifying this uncertainty with Monte Carlo 

ix
simulations and sensitivity analysis can provide useful information to managers. No one model 

will address all needs for estimating restoration benefits and priorities; multiple models are 

needed. Models are population specific due to unique characteristics of each watershed and 

population, so applying findings from one watershed or population to another should be done 

with caution and account for differences in habitat and population characteristics between basins. 

In addition, models that directly incorporate data from the subject watershed or population 

should generally be given more weight than models based on extrapolations from other basins.

x
Acknowledgments

This work was supported by funding from NOAA under the Federal Columbia River 

Power System Biological Opinion. A portion of the literature review on the effectiveness of 

restoration techniques was funded by the Bonneville Power Administration. Patty Dornbusch, 

Tom Cooney, and others from the NOAA Fisheries West Coast Region and Northwest Fisheries 

Science Center provided helpful comments that greatly improved the quality and clarity of this 

report. We thank Jennifer O’Neal, Tetra Tech Inc., for reports and information on ongoing 

evaluations of restoration projects funded by the Washington State Salmon Recovery Funding 

Board and Oregon Watershed Enhancement Board. We thank Clara Salazar, Northwest and 

Alaska Fisheries Science Centers Library, for locating hard-to-find documents. We also thank 

Ed Quimby, Northwest Fisheries Science Center, for technical editing and formatting, which 

improved the organization, accuracy, and usability of this report.

xi
xii
Introduction

A major underpinning of recovery efforts for Pacific salmon (Oncorhynchus spp.) listed 

under the Endangered Species Act is that there is a strong relationship between freshwater 

habitat quantity and quality and salmon abundance, survival, and productivity in the freshwater 

environment. This is a major component of Endangered Species Act recovery plans and 

biological opinions for salmon and steelhead (O. mykiss), including the 2008 Biological Opinion 

(BiOp) for the continued operation of the Federal Columbia River Power System (FCRPS). The 

Reasonable and Prudent Alternative (RPA) for the 2008 FCRPS BiOp takes a comprehensive 

approach that includes, in general, a 10-year operations and configuration plan for the FCRPS 

facilities as well as for mainstem effects of other hydropower projects on Columbia River 

tributaries operated for irrigation purposes. The BiOp sets performance standards for per-dam 

survival for migrating juvenile fish and includes habitat, hatchery, and predation management 

actions to mitigate the adverse effects of the hydropower system, as well as research, monitoring, 

and evaluation actions to support and inform adaptive management.

With regard to habitat, the RPA (FCRPS BiOp 2008) includes an expanded habitat 

program to protect and improve tributary and estuary environments and reduce limiting factors, 

based on the biological needs of listed fish. The tributary habitat program requires 

implementation of habitat improvement actions, including actions to protect and improve 

mainstem and side channel habitat for fish migration, spawning, and rearing and to restore 

floodplain function. These actions are intended to meet performance targets for 56 salmon and 

steelhead populations. The targets, which correspond to survival improvements, are incorporated 

into the RPA.

Given that restoration of tributary habitat in the Columbia River basin is a key 

underpinning of the FCRPS BiOp (2008), it is important to 1) document our understanding of the 

relationship between habitat quantity and quality and salmon production, 2) quantify the 

improvements in salmon production and survival that can be expected with different restoration 

actions, and 3) use models to help identify habitat factors limiting production and quantify 

population-level responses to restoration. This technical memorandum provides a synthesis of 

scientific literature and our current level of knowledge on these three topics. We begin with a 

summary of basic salmonid-habitat relationships, then discuss human impacts to habitat, 

restoration effectiveness, and the use of fish-habitat models to estimate population responses to 

habitat.
Fish-Habitat Relationships

The relationship between a species and the habitats utilized is fundamental to its 

persistence over time. Fish such as salmonids depend on a suite of habitat types and associated 

environmental conditions over the course of their life cycle that is necessary for individual 

survival and, ultimately, population sustainability (Bjornn and Reiser 1991). Habitat 

requirements for salmonids thus include physical features (i.e., habitat area, wood and instream 

cover, etc.), and the environmental conditions associated with those features (i.e., streamflow, 

temperature, etc.). Habitat requirements also include biological factors (i.e., predation, 

competition, food, etc.) that can strongly influence and modify habitat requirements at any 

salmonid life stage (Southwood 1977, Rosenfeld 2003). Thus knowing the habitat type, amount, 

and optimal environmental conditions for each life stage typically defines the habitat 

requirements for salmonids (Rosenfeld 2003).

Salmonids are perhaps the most thoroughly studied of all fishes; decades of research have 

documented considerable information on the habitat quantity and quality requirements for 

Pacific salmonids by life stage and species (Bjornn and Resier 1991, Groot and Margolis 1991, 

Quinn 2005). Rather than a detailed review of all this literature, in this section we provide a 

brief overview of habitat requirements for major freshwater life stages from upstream migration 

of adults to downstream migration of juveniles and smolts. Upstream migration of returning 

adult salmonids from the ocean requires access, adequate flow, and a specified range of water 

temperature and turbidity levels that do not delay migration (Bjornn and Reiser 1991). Once on 

their spawning grounds, Pacific salmonids are affected by multiple variables at various scales—

regional (climate, elevation, topography, geology), watershed (stream channel gradient, size,

type), stream reach (stream temperature, channel hydraulics), and site (depth, velocity, substrate 

size)—which determine the amount and condition of salmonid spawning habitat (Beechie et al. 

2008).

Regional variables influence the spatial timing and life history strategies of salmonids 

(Beechie et al. 2008). For example, Chinook salmon (O. tshawytscha) at colder, higher elevation 

sites typically spawn earlier than Chinook salmon at warmer, lower elevation sites (Beechie et al. 

2006). Incubation takes longer in colder sites, thus the need for earlier spawn timing (Beechie et 

al. 2008). Distance to sea and hydrologic regime can also determine the dominant life history 

strategies for Chinook salmon (Taylor 1990, Beechie et al. 2006). Spawning location and, to a 

lesser extent, timing are controlled by variables at the watershed scale, such as the size and 

steepness of the stream channel. Large-bodied species or larger individuals within a population 

are unlikely to access the smallest tributaries, thus instream flow requirements increase as stream 

size decreases towards the headwaters (Baxter 1961, Fukushima 1994, Beechie et al. 2008). 

Stream channel pattern associated with specific stream reach types (i.e., pool-riffle channel 

types) located in specific parts of a watershed can determine the relative density patterns of 

Chinook salmon, coho salmon (O. kisutch), and Atlantic salmon (Salmo salar) (Montgomery et 

al. 1999, Moir et al. 2004). Reach-specific and site-specific variables control the location of 

2
suitable holding and spawning habitats as well as areas of groundwater upwelling, helping to 

determine a subset of preferred spawning sites relative to the total available area (Bjornn and 

Reiser 1991, Groot and Margolis 1991).

Once in the gravels, the egg-to-fry life stage for salmonids requires adequate dissolved 

oxygen levels and water temperature so eggs can develop into alevins, move through the gravels, 

and move up into the stream or lake environment. Fine organic material and sediment must be at 

low levels (typically <15–20%) so they do not entomb salmon redds or suffocate or reduce 

development of embryos (Jensen et al. 2009). In addition, streamflow and sediment transport 

must not exceed levels that mobilize the streambed to the point that it scours gravel to the depth 

that incubating eggs and embryos are injured or killed (Montgomery et al. 1995, 1999).

The freshwater rearing of juvenile salmonids also has habitat quantity and quality 

parameters at the watershed, reach, and site scale that are critical to the survival of juvenile 

salmonids. At the watershed scale, juvenile salmonids use, move, and grow in mainstem, 

tributary, and floodplain habitats throughout their time in freshwater (Quinn and Petersen 1996,

Kahler et al. 2001, Jeffres et al. 2008). The connectivity between these habitats is critical, 

particularly for species that overwinter, such as coho salmon, stream-type Chinook salmon, and 

steelhead, because summer growth and fish size at the onset of winter are important predictors of 

survival, particularly in streams with limited winter growth opportunities (Bustard and Narver 

1975, Reeves et al. 1989, Nickelson et al. 1992, Brakensiek and Hankin 2007). This is consistent 

with previous studies that have demonstrated higher overwinter survival of larger juvenile 

salmon (Ebersole et al. 2006, Brakensiek and Hankin 2007, Jeffres et al. 2008, Roni et al. 2012). 

This is important because factors which decrease growth of juvenile salmonids during freshwater 

rearing also have the potential to reduce juvenile survival to the smolt stage, as smolt size within 

a given cohort is positively correlated with marine survival (Holtby et al. 1990, Quinn and 

Peterson 1996, Connor and Tiffan 2012). At the reach and site scale, the amount of available 

slow water habitat, cooler temperature regimes in the summer and warmer temperature regimes 

in the winter, woody debris and available cover from predators, and adequate food resources all 

play a key role in determine optimal juvenile salmonid habitat (Everest and Chapman 1972, 

Hillman et al. 1987, Sommer et al. 2001, Rosenfeld et al. 2005, Jeffres et al. 2008).

Estuarine habitats are also important for anadromous salmonids, as many rely on the 

estuary for migration, transition to the ocean environment, rearing, and refuge (Healey 1982, 

Thorpe 1994, Bottom et al. 2005, Rice et al. 2005). Juvenile salmonids may spend anywhere 

from a few days to months in the estuary, depending on the species and life history type. For 

example, subyearling migrant Chinook salmon can reside in estuarine environments for months, 

initially utilizing tidal creeks and other shallow, nearshore habitats before moving to deeper 

water as they increase in size and move downstream (Healey 1982, 1991, Bottom et al. 2005). 

Other salmonids, such as steelhead or yearling Chinook smolts, may migrate quickly through the 

estuary to the marine environment. However, unlike in the freshwater environment, salmonids in 

the estuary must adjust physiologically to salt water, as well as feed and orient for their return 

migration (Simenstad et al. 1982, Thorpe 1994). Habitat quality in these estuarine environments 

(i.e., available habitats, food resources, water temperatures) affect the growth rates of juvenile 

salmonids (Neilson et al. 1985). Habitat quantity in estuaries has also been shown to be critical 

to the survival of juvenile salmonids. For example, the amount of estuarine area in naturally 

3
functioning condition has been correlated to survival from the smolt to adult stage for Chinook 

salmon (Magnusson and Hilborn 2003).

4
Impacts of Management Actions on Fish Habitat

Anthropogenic actions can disrupt natural watershed processes (e.g., delivery of water, 

sediment, nutrients, wood), alter riparian and floodplain functions, or block fish access to 

habitats, all of which can have deleterious effects on aquatic ecosystems and salmonid 

populations (Pess et al. 2002, Karr 2006, Beechie et al. 2010). First and foremost, habitat loss or 

isolation has greatly reduced the amount of available salmon habitat in the Columbia Basin and 

elsewhere. Habitat loss can result from direct manipulations such as blockages to fish migration 

(McClure et al. 2008), disconnection of mainstem river and floodplain habitats through the 

construction of levees or bank revetments (Collins et al. 2002), and filling of floodplain channels 

through the conversion of lands to agriculture or urbanized areas (Beechie et al. 1994). 

Simplifying habitat in such a manner can result in the elimination or disconnection of salmonid 

spawning and rearing habitats, dramatically reducing salmonid habitat carrying capacity in river 

ecosystems (Beechie et al. 2013b). A loss in habitat carrying capacity through these and other 

actions not only can result in a decrease in salmonid abundance, but also can have deleterious 

effects on other aspects of salmonid populations, such as decrease in genetic diversity (Bottom et 

al. 2005, Ozerov et al. 2012).

The degradation of habitat quality from human actions such as logging, urban 

development, mining, road building, and agriculture activities has also been well documented 

(see Meehan 1991 for detailed reviews). For example, timber harvest activities and associated 

road building have led to increased sediment supply, removal of riparian vegetation, filling of 

pools, changes in peak and high flows, loss of in-channel wood, reduced pool spacing, and 

simplification of instream habitat (Salo and Cundy 1987, Holtby 1988, Murphy 1995, Spence et 

al. 1996), all of which can negatively impact salmon populations and reduce survival at various 

life stages. In particular, the loss of pools and loss of wood can result in spawning areas no 

longer being utilized by adult Chinook salmon and coho salmon due to the loss of holding habitat 

prior to spawning (Montgomery et al. 1999). The loss of such habitats in Washington state’s 

Puget Sound has reduced the amount of spawnable habitat by almost 33% (Pess et al. 2002). In 

addition, the loss of these features can result in loss of preferred juvenile coho salmon and 

steelhead habitat (Beechie et al. 2003). Even if pools are available, utilization may not occur due 

to other factors such as stream temperature. Torgersen et al. (1999) found that highest reach 

density of large pools (depth > 0.7 m) in both the north fork and middle fork of the John Day

River occurred downstream of the reaches occupied by adult Chinook salmon. Stream 

temperatures in the downstream reaches of both forks exceed the tolerance level for spring 

Chinook salmon, thus rendering numerous downstream pool habitats inaccessible (Torgersen et 

al. 1999). This indicates that trade-offs between pool availability and stream temperature play 

important roles in determining the longitudinal extent and carrying capacity of spring Chinook 

salmon holding habitat (Torgersen et al. 1999).

Similarly, habitat degradation from removal of water from a stream (abstraction) during 

key life stages can result in reduced freshwater salmon productivity (Arthaud et al. 2010, 

Grantham et al. 2012). The loss of tributary streamflow due to water use during the early life 

5
stages of spring Chinook in the Salmon River basin, Idaho, was an important predictor of adult 

return rates (Arthaud et al. 2010). Juvenile steelhead survival is affected by the magnitude of 

summer flow and the duration of low-flow conditions in coastal California watersheds, and is 

considered a limiting factor to steelhead productivity (Grantham et al. 2012). Conversely, 

increases in the frequency or magnitude of flood flows due to natural (increased precipitation) 

and anthropogenic factors (increases in stream runoff due to impervious surfaces, loss of 

vegetation, and increased road density) (Booth and Jackson 1997) can have deleterious effects on

specific life stages that lead to reduced survival and productivity of salmonids (Greene et al. 

2005, Waples et al. 2008). Greene et al. (2005) found that as magnitude of flood events 

increased, productivity declined in a Puget Sound Chinook salmon population. Waples et al. 

(2008) identified reduced potential survivorship at the egg-to-fry life stage of a Chinook salmon 

population in Puget Sound due to substantial increases in the magnitude and timing of flood 

flows since the late 1920s. Bigger floods have predictable effects on salmonids (more extensive 

scouring of redds, entombment of eggs by sediment, reduced oxygen in redds because of higher 

levels of organic matter, and downstream displacement of recently emerged fry), leading to 

generally reduced survival in early life stages (Quinn 2005). Thus anthropogenic actions that 

alter, reduce, or simplify aquatic habitats can have negative impacts on salmonid populations.

Freshwater habitat restoration efforts attempt to reverse the trajectory of a reduction in 

habitat quantity and quality from a variety of human activities (NRC 1996, Roni et al. 2002, 

Bernhardt et al. 2005, Roni and Beechie 2013). Understanding what and where to restore 

processes or habitats requires analysis of watershed processes and how they have been disrupted, 

assessment of habitat losses resulting from human actions, and modeling how those changes 

impact salmon populations (Beechie et al. 2013a). The purpose of these analyses is to 

understand 1) which habitat losses have been most important for a salmon population and 2) the 

causes of those habitat changes. Once these are known, it is possible to develop a restoration 

strategy that will focus effort on the most important factors that limit recovery of a salmon 

population. Ultimately, the most successful restoration efforts will be those that address the root 

causes of habitat and population declines, so that natural processes sustain habitats over time and 

continued management intervention is not needed.

Habitat restoration efforts focused on reconnecting lost mainstem and tributary habitats 

include dam removal or breach, culvert replacement, and the development of fish passage 

structures (Pess et al. 2005). Levee setbacks and removals and the reconnection of freshwater 

sloughs, wetlands, and lake environments are used to reconnect floodplain and estuarine 

environments (Pess et al. 2005). Quality-oriented aquatic habitat restoration efforts can include 

reestablishment of native riparian vegetation, reduction of unnatural sediment supply from roads 

and bank erosion due to land use impacts, and reintroduction of wood, nutrients, and mammals 

such as beaver (Castor canadensis) in stream channels. Many of these efforts attempt to restore 

the natural watershed processes that salmonids evolved and persisted under for tens of thousands 

of years (Beechie et al. 2010). In the following section, we discuss in detail what is known about 

the effectiveness of multiple restoration action types that are implemented in the Columbia Basin 

and beyond to increase the quantity and quality of salmon habitat.

6
Effectiveness of Common 

Restoration Techniques

Several different types of restoration (habitat improvement) actions are being 

implemented across the Columbia Basin to improve tributary habitat and recover salmon and 

steelhead populations. These include but are not limited to fish passage, instream structures, 

floodplain restoration, riparian improvement, sediment reduction, land acquisition, and instream 

flow augmentation (see Table 1 for project categories used by action agencies).

These project actions are designed to address specific limiting factors1 that have been 

identified for each population or subbasin. Obviously the investment in these projects is large

and improvements in survival in tributaries based on these actions are one of the underpinnings 

of the FCRPS BiOp. Several long-term studies including intensively monitored watersheds 

(IMW)2 are underway within the Columbia Basin to evaluate the effects of different actions on 

limiting factors and, more importantly, the effects of these actions on salmon and steelhead 

survival. However, these efforts are early in the implementation process and only very 

preliminary information on the effects of actions on survival and production is available. 

Fortunately, numerous studies reporting on the physical and biological effectiveness of 

restoration actions in other parts of the Northwest and the world are available. In this section we 

summarize the published literature documenting the effectiveness of each major action category 

outlined in Table 1. We then discuss limiting factors addressed by these actions and general 

findings that are useful for project design and implementation.

Literature Reviewed

Two comprehensive reviews of the published literature on effectiveness of habitat 

improvement have been completed in the last decade. The first, Roni et al. 2002, focused 

primarily on regional literature, while the second, Roni et al. 2008, reviewed literature published 

throughout North America, Europe, and elsewhere. The latter examined 345 papers that reported 

the results of effectiveness monitoring of various habitat improvement techniques. In this 

technical memorandum, we supplemented these two reviews with other papers and technical 

reports that have been published between 2006 and 2013. As a result, we examined an additional 

64 papers or reports, a total of 409 published studies. While many of these documents examine 

restoration efforts outside the Columbia River basin and the Pacific Northwest, the techniques 

used in other countries are similar to those used in the basin and in many cases focus on 

salmonids. For some action types, such as remeandering of stream channels, much of the 

1 In the context of the FCRPS BiOp and salmon recovery plans, a “limiting factor” is a problem or degraded habitat 

that is thought to reduce survival or population productivity. There may be several in any given watershed or 

population and typically a detailed analysis has not been conducted to determine what habitat or life stage is actually 

limiting the population.

2 Intensive monitoring in one or more catchments to determine watershed-level or population-level fish and habitat 

responses to restoration treatments.

7

 
Table 1. The Bonneville Power Administration (BPA) Fish and Wildlife Program habitat improvement 

project categories and subcategories, and the number of published studies that examined this type 

of restoration. Most of these studies occurred outside the Columbia Basin; little published 

literature on effectiveness of actions implemented in the basin is yet available.

Project action category Subcategory

No. of studies 

located

Fish passage 22 (mostly

Barriers dam removal)

Entrainment/screens

Instream structures 209

Complexity

Stabilization

Large engineered structures

Spawning gravel addition

Beaver introductions

Off-channel/floodplain habitat 82

Side channel

Floodplain

Wetland restoration

Confinement

Riparian improvement 53

Fencing

Planting

Removal

Sediment reduction 27

Roads

Agricultural

Acquisition and protection 1

Acquisition

Protection

Flow augmentation 15 (flood 

Water quality restoration)

Barriers

existing literature is from European studies (except see Utz et al. 2012); however, the vast 

majority of published evaluations of habitat improvement techniques is from North America 

(70%), with most studies from the western United States and Canada. Much of the information 

on fish response to restoration is on coho salmon and steelhead in coastal streams rather than in 

the Interior Columbia Basin, though many of the results are applicable to Chinook and coho 

salmon and steelhead in the basin. Rather than provide an exhaustive summary of each paper 

here, we provide a concise synthesis of studies and their general findings. Where appropriate,

we refer to key studies that support our points. In many instances, rather than cite all the papers 

referenced in the two aforementioned literature reviews, we cite the reviews themselves. A 

complete list of all the literature examined and a brief summary of key findings from each of 

those studies is provided in Appendix A.

8
Fish Passage

Barrier Removal

Studies evaluating the effectiveness of projects that have removed impassable 

culverts/dams or installed fish passage structures in North America and elsewhere have 

consistently shown rapid colonization by fishes, with colonization time positively related to 

distance to nearby source populations (Burdick and Hightower 2006, Stanley et al. 2007, Roni et 

al. 2008, Zitek et al. 2008, Nakamura and Komiyama 2010, Pess et al. 2012b, Roni et al. 2013). 

Success of fish passage through culverts and fish passage structures depends on appropriate 

design and installation (slope, width, length, percent the culvert is countersunk), as well as 

regular maintenance (Price et al. 2010).

The benefits to fish populations of removal of culverts, small dams, and other migration 

barriers have been well documented in North America, Europe, and Asia. Studies show that fish 

typically migrate upstream and colonize new habitats rapidly (Burdick and Hightower 2006, 

Stanley et al. 2007, Kiffney et al. 2009, Nakamura and Komiyama 2010, Pess et al. 2012b, Roni 

et al. 2013). For example, the installation of a fish passage structure on a water diversion dam on 

the Cedar River in Washington state resulted in the recolonization of newly accessible habitat by 

juvenile and adult salmon and steelhead within 5 years (Kiffney et al. 2009, Pess et al. 2011). 

Martens and Connally (2010) demonstrated movement and recolonization of Chinook salmon, 

steelhead, and other fishes after improved passage at irrigation diversions in the Methow River 

basin. Similarly, evaluation of culvert removal projects in Washington state indicated increased 

fish numbers within 2 years of culvert removal or replacement (Tetra Tech 2010). Most studies, 

however, have focused on removal of complete barriers to migration, while many culverts may 

only be partial barriers to migration—that is, barriers only during some flows, seasons, or years 

or for some life stages. Replacing partial barriers can be successful as well (Tetra Tech 2010), 

but such projects are more difficult to evaluate and thus less frequently evaluated.

Reviews of the effectiveness of habitat improvement have consistently reported removal 

of barriers or installation of fish passage as one of the most effective at increasing fish numbers 

and highest priority habitat improvement measures for salmon, steelhead, and other stream fishes 

(Roni et al. 2002, 2008). The rate at which salmon and trout recolonize these habitats, however, 

is highly dependent on the amount and quality of habitat upstream of the barrier, and the size of 

the downstream or nearby source population (number of salmon or trout returning that could 

colonize habitat) (Pess et al. 2008, 2012b). Therefore, compliance monitoring and periodic 

maintenance are often used to ensure that fish passage structures or new culverts function 

properly and meet original design criteria.

Entrainment

Most monitoring of screening projects is compliance rather than effectiveness 

monitoring, focusing on whether installation or upgrading screens has reduced entrainment of 

fish into irrigation or water withdrawal systems. One of the few studies on diversion-screen 

effectiveness in the Pacific Northwest found that projects sampled exceeded most (80%) of the 

NOAA criteria for screening projects (Tetra Tech 2010). It recommended continued compliance 

monitoring of these projects, as screens need periodic cleaning and maintenance to retain their 

9
10 

efficiency. Walters et al. (2012) modeled that the estimated cumulative effect of the unscreened 

diversions in the Lemhi River could be a loss of 71.1% of outmigrating Chinook salmon smolts 

due to entrainment. The Lemhi has undergone an extensive screening program and most 

diversions encountered by Chinook salmon have been screened. The modeling by Walters et al. 

(2012) suggests that this screening program has potentially reduced Chinook mortality due to 

entrainment to 1.9%. 

Instream Structures

The placement of instream structures such as logs, logjams, cover structures or boulders, 

and gravel addition are some of the oldest and most common methods of increasing pool area, 

habitat complexity, and spawning habitat (Roni et al. 2013). In fact, the vast majority of 

published studies on effectiveness of habitat improvement have examined instream structures 

(Roni et al. 2002, 2008). For example, of the 409 published evaluations of effectiveness that we 

reviewed and summarized in Appendix A, 209 examined placement of instream structures. Most 

of these studies have focused on the effects of such actions on salmonid fishes (particularly coho 

salmon, steelhead/rainbow trout (O. mykiss), or other trout species). The vast majority of these 

have shown a positive response (increased abundance) for juvenile salmonids (Figure 1 and 

Figure 2). The lack of response or small decrease reported in some studies is largely because 

watershed processes (e.g., sediment, water quality, etc.) were not addressed, monitoring had not 

occurred long enough to show results, or the treatments resulted in little change in physical 

habitat (Roni et al. 2013). This emphasizes the need for restoring processes (process-based 

Figure 1. Mean increase in coho salmon, steelhead, and Chinook salmon smolts reported from different 

types of habitat improvement examined by Roni et al. 2010. Note that data are largely from 

coastal streams in Western Washington and Oregon not inhabited by Chinook salmon; Chinook 

data were only available for constructed logjams.
Figure 2. Percent of published studies evaluating instream habitat improvement that have shown an 

increase, small decrease, or no response of juvenile and adult salmon to placement of instream 

structures. Overall, 99 studies reported information on juvenile salmonids, 14 on adult 

salmonids, and 24 on nonsalmonids. No response or decrease were typically due to short-term 

monitoring, instream treatments that had little effect on physical habitat or water quality, other 

processes not being restored prior to instream treatments, or improvement in habitat for one life 

stage leading to a reduction in habitat for another. (Data from Roni et al. 2008.)

restoration) prior to or in conjunction with habitat improvement (Roni et al. 2002, 2008, Beechie 

et al. 2010, Roni and Beechie 2013).

Placement of single logs or log structures has been shown to be effective for juvenile 

coho salmon and, to a lesser extent, steelhead, cutthroat trout (O. clarkii clarkii), and other 

species that rear in freshwater for several months (Roni and Quinn 2001, Roni et al. 2002, 2008). 

This was confirmed by recent meta-analysis of published studies on large wood placement by 

Whiteway et al. (2010). Constructed logjams have also been shown to be useful for creating 

habitat for juvenile Chinook salmon, coho salmon, steelhead, and other fishes (Abbe et al. 2002, 

Roni et al. 2002, 2008, Pess et al. 2012a). For example, ongoing monitoring of constructed

logjams in the Grays River (a lower Columbia River tributary) reported improvements in pool 

area, habitat complexity, and fish numbers following logjam construction (Hanrahan and Vernon 

2011). In addition to improvements in physical habitat, the structures themselves have been 

shown to trap organic material and boost production of aquatic insects, thus not only providing 

habitat, but food source (Coe et al. 2006, 2009). Less research has focused on adult salmon use 

of instream structures (Figure 2), but several studies have shown benefits for spawning Chinook 

salmon and steelhead (Merz and Setka 2004, Roni et al. 2008, Senter and Pasternack 2011), as 

well as to juvenile Chinook growth (Utz et al. 2012). While a few studies have examined 

juvenile Chinook salmon and steelhead response to placement of instream structures, most 

studies have focused on coho salmon and coastal streams. Thus additional information is needed 

on effectiveness of these action types for Chinook salmon and steelhead in the Columbia Basin.

11
Habitat improvement efforts also include adding gravel to a stream reach. The addition 

of gravel or placement of structures to trap gravel can lead to the creation of suitable salmon 

spawning habitat. Several studies have shown increased number of salmon or steelhead redds or 

spawners following gravel addition (e.g., Merz et al. 2004, Roni et al. 2008, McManamay et al. 

2010). Studies on gravel additions below dams suggest that salmon successfully reproduce in 

placed gravels and macroinvertebrates quickly colonize new gravels (Merz et al. 2004, Merz and 

Chan 2005). Gravel additions are less likely to lead to improvements in spawning habitat, 

spawning numbers, and reproductive success of salmonids in areas with low velocities and high 

levels of fine sediment (Iversen et al. 1993, Roni et al. 2013). Other methods to create or 

improve spawning habitat (e.g., fine sediment traps, gravel cleaning) have met with only shortlived improvements or little success because high levels of fine sediment often overwhelm them 

(Roni et al. 2013).

A relatively new type of instream habitat improvement is the addition of structures to 

enhance beaver populations. The importance of beaver for creating habitat for coho salmon has 

been well documented (Reeves et al. 1989, Roni et al. 2008). Recent work in Bridge Creek, a 

tributary to the John Day River, has demonstrated the importance of beaver in restoring 

floodplain habitat and creating habitat for steelhead and Chinook salmon in interior Columbia 

River tributaries (Pollock et al. 2007, 2012). Projects that reintroduce beaver, install instream 

structures, or add food to entice beaver to construct dams or colonize a stream reach have gained 

popularity in the last decade (DeVries et al. 2012). Studies in North America and Europe have 

shown that where beaver are reintroduced and protected from harvest or predators, and where a 

suitable beaver food source exists, the beaver rapidly recolonize and modify stream habitats. 

Recent studies have also shown that “beaver support structures,” such as those constructed on 

Bridge Creek in the John Day watershed, can lead to construction of beaver dams and 

aggradation of incised channels (DeVries et al. 2012, Pollock et al. 2012). Unpublished evidence 

from Bridge Creek also indicates improvements in juvenile steelhead abundance and survival 

following placement of beaver enhancement structures (Pollock unpubl. data).

Several factors appear to limit the success of in-channel projects; the most important 

appear to be assuring that upstream and watershed processes including sediment and water 

quality have been addressed, whether habitat complexity or pool area is limiting fish production, 

and the intensity of habitat improvement (Roni et al. 2013). Moreover, the vast majority of these 

studies have focused on smaller streams (<20 m bankfull width), and on local or reach-scale 

effectiveness. While some work has been recently published (Utz et al. 2012), additional work is 

needed to examine response of techniques used in larger rivers, response of Chinook salmon, and 

watershed-scale or population-level responses. The total amount or extent of restoration is also 

an important factor, as recent modeling suggests that monitoring to detect population-level 

responses to restoration may require restoring 20% or more of habitat in a watershed.

Off-Channel/Floodplain Habitat

Four major categories of floodplain or off-channel habitat restoration are discussed 

including reconnecting existing habitats (ponds, side channels, or wetlands), removing levees or 

setting back levees to allow remeandering of channel or reconnection with floodplain, 

constructing ponds or side channels, and restoring meanders.

12
Reconnection

Similar to studies examining dam or culvert removal, studies on effectiveness of 

floodplain habitat reconnection have consistently shown rapid recolonization of newly accessible 

habitats by salmonids and other fishes (Sommer et al. 2001, Roni et al. 2008). Reconnected 

floodplain ponds, side channels, and wetlands have proven to be effective at providing habitat for 

juvenile salmonids such as coho salmon (Figure 1) and Chinook salmon (Richards et al. 1992, 

Henning et al. 2006, Roni et al. 2008). Which salmonid species benefit the most largely depends 

on the streamflow, depth, morphology, and water source; ponds and wetlands with little flow 

were used mostly by coho salmon, while surface water–fed side channels were generally more 

effective for Chinook salmon and various trout species (Pess et al. 2008).

Levee Removal/Setback

Levee removal or modification is an increasingly common approach for restoring 

floodplain habitat. Published studies in the United States and Europe demonstrate that these 

techniques can reestablish connectivity between a river and its floodplain and lead to a wider, 

active floodplain. The techniques can improve exchange between surface and subsurface flow, 

water residence time, overbank fine sediment deposition, and organic matter retention, as well as

increase sinuosity, riparian and aquatic habitat diversity, and complexity (Jungwirth et al. 2002, 

Muhar et al. 2004, Konrad et al. 2008). This can lead to increased primary productivity in newly 

established or reconnected habitat, thus providing valuable food resources (Schemel et al. 2004, 

Ahearn et al. 2006). Fish rearing in floodplain habitats created or reconnected following levee 

removal or setbacks often have higher growth rates than those in the main stem (Sommer et al. 

2001, Jeffres et al. 2008). Most studies on the effectiveness of levee modification and setbacks 

have focused on physical aspects and hydrologic connectivity of habitats. Depending on stream 

power and cohesiveness of bank material, channels can begin to move laterally and begin to 

recover their sinuosity fairly rapidly following removal of bank armoring (Bolton and Shellberg 

2001, Jungwirth et al. 2002, Muhar et al. 2004, Roni et al. 2008).

Side Channel and Pond Construction

Most of our information on the fish response to floodplain improvement is derived from 

studies on fish response to constructed ponds and side channels (Morley et al. 2005). 

Constructed floodplain habitats have consistently been shown to provide habitat for juvenile 

salmonids and, in some cases, to improve overwinter survival (Solazzi et al. 2000, Giannico and 

Hinch 2003, Morley et al. 2005, Roni et al. 2006a). Construction of groundwater-fed side 

channels can be an effective strategy for creating spawning and rearing habitat for salmon and 

trout (Bonnell 1991, Cowan 1991, Roni et al. 2008). For example, monitoring of a recently 

constructed spawning/side channel in Duncan Creek (lower Columbia River tributary) showed 

high levels of chum salmon (O. keta) egg-to-fry survival (50–85%) and ideal spawning and 

incubation conditions (Hilton 2010). As with reconnected floodplain habitats, juvenile and adult 

salmon, trout, and other fishes rapidly colonize newly created habitats. The success of these 

projects depends largely on their connection with the main channel and their morphology and 

depth.

13
Channel Restoration

Restoring the sinuosity or remeandering straightened and confined channels is a common 

technique to restore constrained or channelized streams (Pess et al. 2005, Vought and 

Locoursiere 2010). Channel remeandering also typically includes the placement of boulders, 

wood, and other instream structures to create habitat complexity and cover, as well as riparian 

replanting to restore the riparian area and protect and stabilize soil exposed during construction. 

Most of the information on effectiveness of channel remeandering comes from European studies. 

Remeandering straightened or incised channels leads to dramatic increases in total stream length 

and habitat areas, sometimes by as much as 60% (Iversen et al. 1993). European studies on 

remeandering have demonstrated improvement in habitat complexity and channel morphology, 

flood frequency, amount of water passing onto the floodplain, and nutrient retention, as well as 

an increase in sediment deposition and sediment-associated phosphorous, and a decrease in 

erosion (Kronvang et al. 1998, Sear et al. 1998, Pedersen et al. 2007). Improvements in physical 

habitat, fish species diversity, and growth have also been demonstrated in some remeandered 

stream segments (Jungwirth et al. 1995, Baldigo et al. 2010). Most notably, Utz et al. (2012) 

found increased growth of juvenile Chinook salmon following remeandering of a California 

river. In contrast, other studies have reported little fish response to remeandering (Moerke and 

Lamberti 2003, Cowx and Van Zyll de Jong 2004, Pedersen et al. 2007). The lack of response of 

fish and some other biota has largely been attributed to water quality and other broader or 

upstream problems that had not been addressed (Cowx and Van Zyll de Jong 2004), the stocking 

of fish, continuation of other management activities (Pedersen et al. 2007), or attempting to 

design a static meandering channel in a highly dynamic stream reach (Miller and Kochel 2010). 

Despite these less than consistent findings on fish response, remeandering of streams in the 

Columbia Basin and elsewhere in the Northwest shows great promise to increase total habitat, 

restore floodplain habitats, and increase fish numbers. While it appears to be a successful 

restoration strategy, additional fish data monitoring of these projects is needed in the Columbia 

Basin.

Riparian Improvement

Riparian habitat improvements fall into three general categories: planting and other 

silviculture treatments, fencing, and invasive species removal. Riparian treatments often include 

a combination of these habitat improvement approaches.

Riparian Planting and Silviculture Treatment

Because of the long lag time needed to measure a response for riparian planting, 

monitoring of most riparian planting has focused on the short-term survival of the planted 

species (Pollock et al. 2005, Roni et al. 2008). Several BPA-funded habitat improvement 

projects have been monitoring survival of plantings (e.g., project numbers 1987-100-01, 1997-

056-00, 2003-011-00, and 2007-231-00; project reports available from BPA, P.O. Box 3621, 

Portland, OR 97208-3621). These projects have generally shown relatively high survival rates of 

plantings (>60%) and increases in shade in the first few years following planting. Depth of 

planting, browse protection, exposure, and other site-specific conditions can dramatically affect 

survival.

14
Few studies have examined the response of instream habitat or fish to riparian planting or 

thinning, in part because of the long lag time between tree growth and any change in channel 

conditions or delivery of large woody debris (LWD). In fact, only a few short-term studies have 

examined the response of fish or other instream biota to various riparian silviculture treatments; 

these studies have produced variable results depending on the region and treatment (Penczak 

1995, Parkyn et al. 2003). Moreover, most riparian silviculture treatments influence reach-scale 

conditions and processes, while in-channel conditions are often more affected by upstream or 

watershed-scale features, which may limit the physical and biological response in the project 

area. However, riparian treatments and restoration of the riparian zone are often critical to the 

success of other project types (e.g., instream, floodplain). For example, planting and grazing 

removal lead to increased shade, bank stability, reduction of fine sediment, reduced 

temperatures, and improvement of water quality—all factors that can influence the success of 

instream habitat improvement projects.

Riparian Fencing and Grazing

The effectiveness of riparian fencing (livestock exclusion) and rest-rotation grazing have 

been the subject of several studies in the last 30 years (Platts 1991, Roni et al. 2002, 2008, 

Medina et al. 2005). Improvements in riparian vegetation, bank erosion, channel width, depth, 

width:depth ratios, and fine sediment levels have been well documented in most studies in the 

Pacific Northwest and elsewhere (see Medina et al. 2005 or Roni et al. 2008 for a review, Tetra 

Tech 2010), particularly for complete livestock exclusion. Rest-rotation grazing systems are 

generally less successful than complete livestock exclusion and results depend on livestock 

densities, period of rest, and the ability to actively manage livestock. Fish response to restrotation grazing systems has been highly variable, with a few studies showing positive response 

for rainbow and other trout (e.g., Keller and Burnham 1982, Li et al. 1994, Kauffman et al. 

2002). Similarly, ongoing work in the John Day River basin as part of a BPA-funded project 

shows increases in habitat improvement and juvenile steelhead numbers (Bouwes 2012). 

Overall, however, the vast majority of studies have not detected a measureable fish response to 

elimination or reduction of grazing (Rinne 1999, Medina et al. 2005, Roni et al. 2002, 2008). 

But rather than indicate lack of project effectiveness, the lack of fish response in most grazing 

studies has been partly attributed to the short duration of monitoring, the small size of grazing 

exclosures, and broader scale processes occurring upstream (Medina et al. 2005).

Invasive Species Removal

Similar to riparian planting, studies examining the removal of invasive vegetation have 

focused on the short-term response of vegetation changes. We found no published studies that 

examined effects on channel conditions or fish and aquatic biota. The success of projects that 

remove invasive species is highly dependent on the species in question, local site conditions, and 

the periodic maintenance or follow-up conducted to assure that the species have been eradicated.

Sediment Reduction

Efforts to reduce sediment delivery to streams fall into two major categories: road 

restoration and agricultural treatments. Road restoration or modifications include road 

decommissioning, removal, or upgrades (e.g., stabilization, resurfacing, and increasing stream 

15
crossings). Agricultural treatments include changes in crop rotation, planting, terracing and 

conservation tillage, creation of buffer strips, and other agriculture practices that reduce erosion 

and transport of fine sediment.

Several studies have reviewed the effectiveness of forest road restoration or modification 

efforts. Roni et al. (2008) examined 26 evaluations of various road treatments; they found that 

most published monitoring and evaluation on the effects of road treatments to restore streams 

have focused almost exclusively on physical monitoring of landslides, fine sediment, and runoff. 

Apart from studies that looked at fish recolonization after removing impassable road culverts, 

little monitoring and evaluation has been done to examine the response of fish or other biota to 

road treatments.

Less information exists on the impacts of various agricultural practices on salmon. While 

the agricultural impacts on streams and water quality have been well documented, relatively little 

information exists on the effectiveness of different agriculture practices in reducing fine 

sediment and improving salmon habitat.

Acquisition and Protection

Monitoring and evaluation of land acquisition, conservation easements, and other 

protection measures can be problematic, because they are protection measures rather than active 

restoration. However, protection of existing high quality habitat through acquisition or 

conservation is a critical part of most habitat improvement and may be needed to implement 

riparian, instream, or other habitat improvement techniques. Further, the protection of existing 

high quality, functioning habitats is considered one of the most effective strategies for habitat 

conservation. It is cheaper and more effective to protect high quality habitat and properly 

functioning ecosystem processes than it is to restore or re-create them after they are lost or 

degraded. As discussed above, improvement and recovery of some degraded processes can take 

decades.

In the absence of other habitat improvement measures, monitoring of acquisition and 

protection efforts is typically limited to status and trend monitoring to assure that a habitat 

recovers or does not further degrade, or that degraded areas improve once the habitat is protected 

from further disturbance. Published studies have generally focused on the protection of riparian 

buffers (Roni et al. 2013, see also the Riparian Improvement subsection above). These studies 

have generally indicated that riparian protection through acquisition, easements, or other 

methods can maintain riparian vegetation; lead to reduced sediment, nutrient, and pesticide 

concentrations delivered to streams; and lead to improved bank stability and water quality (e.g., 

Osborne and Kovacic 1993, Barling and Moore 1994, Dosskey et al. 2005, Mayer et al. 2005, 

Puckett and Hughes 2005, Vought and Locoursière 2010, Tetra Tech 2013).

Flow Augmentation

Flow augmentation generally includes two major project types or goals: increases in 

instream or base flows and restoration of more natural flood flows or flood pulses. The later is 

not common in the Columbia River basin to date, but may become more common as we learn 

more about appropriate environmental flows to sustain healthy salmon populations and aquatic 

16
ecosystems. The former, however, is a key habitat improvement strategy in many rivers and 

streams in the Interior Columbia Basin.

There is an obvious and clear relationship between minimum instream flows and

salmonids or other fishes: they require water of adequate temperature and flow to live. 

Moreover, the literature has shown that increases in base flow lead to increases in fish and 

macroinvertebrate production (e.g., Weisberg and Burton 1993, Gore et al. 2001, Lamouroux et 

al. 2006). The response is most dramatic in stream reaches that were previously dewatered or 

too warm to support fish due to water withdrawals (Sabaton et al. 2008, Roni et al. 2013). For 

example, while still underway and data are not published, ongoing studies in the Lemhi River 

show increased spawner and juvenile fish numbers following restoration of instream flows in 

tributaries (Jordan unpubl. data).

Numerous methods exist to set instream flows, base flows, or environmental flows, 

including the Tennant Method (Tennant 1976), Instream Flow Incremental Methodology (IFIM) 

(Stalnaker et al. 1995), and Demonstration Flow Assessment (Railsback and Kadvany 2008). 

However, determining the optimal flow for fish production or the minimum flow needed to 

sustain healthy salmon, trout, and other fish populations remains difficult (Poff and Zimmerman 

2010). This is because it depends on many factors specific to a given stream or subbasin, such as 

gradient, aspect, climatic zone, channel width, riparian zone condition, groundwater sources, 

substrate and geology, and elevation. Obviously, the ideal instream flows would most likely be 

near those that were found historically in a stream before water abstraction and lead to highest 

species and habitat diversity. However, very stable flow and temperature can lead to high 

primary and secondary production and benefit some fish species. Regardless, the restoration of 

more natural flows, whether they are base flows or flood pulses, is critical for the success of 

many habitat improvement techniques such as riparian plantings, floodplain reconnection, and 

instream habitat improvement.

Studies Examining Survival

As noted previously, most studies that evaluated fish response to restoration reported 

changes in abundance (density or number), size, or growth and few examined changes in fish 

survival. Of the 409 studies on restoration we examined, 19 reported on changes in survival 

(Appendix B). These studies mainly focused on floodplain habitats (created or reconnected 

ponds or side channels) and instream habitat improvement (LWD placement, gravel addition) 

and reported results from a variety of species including brown trout (Salmo trutta), brook trout

(Salvelinus fontinalis), Atlantic salmon, coho salmon, Chinook salmon, and steelhead. Of these 

19 studies, about 13 suggested that survival improved postrestoration or was equivalent to that 

found in high quality reference sites. Because of the variety of treatments and species examined 

and small number of studies, drawing firm conclusions is difficult. In general, however, it 

appears that floodplain creation or reconnection projects lead to survival rates for coho and 

Chinook salmon that are equivalent to those found in natural floodplain habitats. Placement of 

LWD and instream structures can lead to increased survival for salmon and trout, with most of 

the evidence being for coho salmon (Rogers et al. 1993, Lonzarich and Quinn 1995, Solazzi et al.

2000, Giannico and Hinch 2003). Improvement of spawning habitat through gravel addition, 

cleaning, or gravel retention structures appears to lead to some improvements in egg-to-fry 

survival for salmon or trout (Overton et al. 1981, Klassen and Northcote 1988, Merz et al. 2004). 

17
A few other studies did modeling or correlation analysis to examine restoration (e.g., Paulsen 

and Fisher 2005, Budy and Schaller 2007). For example, the analysis by Paulsen and Fisher 

(2005) found that the number of habitat improvement actions in a watershed was positively 

correlated with Chinook salmon parr-to-smolt survival in the Snake River basin.

Survival, growth, and movement are all processes or factors that ultimately influence 

population size or total abundance. While survival would seem an appropriate measure of 

restoration effectiveness, it is very difficult and costly to measure in the field. In fact, many of 

the studies that reported survival were very small scale, though a few like Solazzi et al. (2000) 

and Rogers et al. (1993) reported watershed-scale response to restoration. It is much easier and 

therefore much more common to measure changes in fish number or density, which also provide 

direct information on abundance or population size.

Restoration and Limiting Factors

Because most evaluations of different types of restoration actions are from outside the 

Columbia Basin, they have not directly evaluated factors identified as limiting for salmon and 

steelhead populations within the basin (Table 2) Thus it is difficult to quantify the effects of 

specific actions on most limiting factors. Based on the literature, however, we can make a 

qualitative assessment as to the amount of evidence that exists that a particular action addresses 

or eliminates a specific limiting factor, which we summarize in Table 2. This also emphasizes 

that we have considerable information for some actions and limiting factors and little for others. 

For example, restoration actions such as diversion screens, removal of barriers and culverts, and 

placement of instream structures have considerable evidence that they address limiting factors 

(Table 2). While other restoration techniques such as increased instream flows may clearly 

address limiting factors related to flow or temperature, there is less information available on how 

they affect limiting factors related to other water quality factors. This is not to say that they do 

not affect these factors, but that either little information is published on the topic or existent 

studies do not produce consistent results.

The question then becomes: Do management actions that increase habitat quantity and 

quality lead to increased abundance and recovery of salmonid populations? There is evidence to 

suggest that actions to improve longitudinal (i.e., among tributary and mainstem habitats) and 

lateral (i.e., floodplain channels and blind tidal channels in an estuarine environment) 

connectivity do increase habitat quantity and can increase salmonid condition (e.g., size, growth) 

and survival in the short term (Sommer et al. 2001, Roni et al. 2006a, Jeffres et al. 2008), as well 

as overall population size in the long term (Pess et al. 2012b). Increases in habitat quality from 

in-channel restoration actions can also have positive effects on salmonid survival and 

populations (Solazzi et al. 2000, Johnson et al. 2005, Roni et al. 2006b). However, recent 

analyses suggest that large amounts of habitat need to be restored or improved to detect a 

population-level response in salmon or steelhead parr or smolts. For example, Roni et al. (2010) 

found that, based on average responses to various restoration techniques, 20% or more of a 

watershed would need to be restored to detect a 25% change in smolt production. Yet they also 

found that, due to the variation in fish response among projects, 100% of the habitat would need 

to be restored to be 95% certain of detecting a 25% increase in smolt production.

18
Table 2. Limiting factors addresseda by each restoration action type and subtype, and the strength of 

evidence in published literature that a particular action subcategory addresses a limiting factor or 

habitat impairment. The list of action categories and limiting factors was provided by BPA,

August 2012. Acquisitions were not included in the table because little information exists on 

their effects on limiting factors and they often focus on protecting habitat.

Action subcategory Limiting factor/habitat impairment

Evidence from 

the literatureb

Barriers–passage Migration barriers (road crossings) High

Barriers–screens Entrainment High

Habitat complexity Habitat diversity/complexity High

Habitat quality High

Habitat quantity High

LWD High

Pool quality High

Pool quantity High

Side channel connectivity Low

Bank stabilization Habitat quality Medium

Engineered structures LWD High

Beaver introductions Fine sediment Low

LWD Low

Pool quality High

Pool quantity High

Confinement/remeandering Channel alteration and confinement High

Channel complexity High

Channel morphology High

Streambank condition/erosion Low

Streambank instability Low

Side channel Floodplain connectivity Medium

Floodplain Riparian condition and function Medium

Floodplain connectivity Medium

Wetland structure and function Low

Riparian fencing Streambank condition/erosion High

Riparian condition and function High

Riparian planting Streambank condition/erosion High

Riparian condition and function Medium

Invasive plant removal Streambank condition/erosion ?

Riparian condition and function ?

Roads (forest) Water quality (chemical pollution) NA

Water quality (dissolved oxygen) NA

Water quality (heavy metal contamination) NA

Water quality (high turbidity) High

Water quality (pH) NA

Water temperature NA

Fine sediment High

Agricultural Water quality (chemical pollution) High

Water quality (excess nutrients) High

Water quality (low nutrients) NA

19
Table 2 continued. Limiting factors addresseda by each restoration action type and subtype, and the 

strength of evidence in published literature that a particular action subcategory addresses a

limiting factor or habitat impairment. The list of action categories and limiting factors was 

provided by BPA, August 2012. Acquisitions were not included in the table because little 

information exists on their effects on limiting factors and they often focus on protecting habitat.

Action subcategory Limiting factor/habitat impairment

Evidence from 

the literatureb

Agricultural (continued) Water quality (pH) NA

Water temperature NA

Fine sediment High

Flow–water quality Water quality (chemical pollution) ?

Water quality (dissolved oxygen) Medium

Water quality (excess nutrients) ?

Water quality (heavy metal contamination) ?

Water quality (high turbidity) ?

Water quality (low nutrients) ?

Water quality (pH) ?

Water temperature Medium

Instream flows/water quantity High

Flow–barriers Passage or migration barriers (diversions) Medium

a The term “limiting factor” here refers to a major habitat impairment rather than a factor limiting a specific salmon 

life stage. By addressing a limiting factor, we mean that one of the benefits of that action is an improvement in that 

limiting factor. For example, if fine sediment is a limiting factor, then forest road removal would reduce the levels 

of fine sediment.

b High = many studies have confirmed this, Medium = some studies have documented this, Low = little to no 

information is available, ? = no information reported, and NA = not applicable (limiting factor not typically 

measured or addressed by this action type.

Project Implementation and Design

Our review of the existing literature suggests that most restoration techniques lead to 

improvements in physical habitat when implemented properly and in the proper ecological 

context. Considerably less information exists on fish response, particularly for Chinook salmon. 

The best evidence of projects that successfully improve habitat or increase fish numbers is for 

those techniques that directly modify habitat (barrier removal, floodplain restoration, instream 

habitat improvement), in part because physical and biological responses are rapid and relatively

easily detected. Other techniques that restore reach-scale or watershed-scale processes (riparian

restoration, sediment reduction) often require long-term monitoring (decades) to document 

improvements, but these techniques are often critical to the success of techniques that focus on

improving instream habitat. The review also suggests a number of implementation and design 

factors that influence project success, which we summarize in Table 3.

Restoration Effectiveness at the Population Level

Population-scale or watershed-scale assessments of the effectiveness of restoration 

actions are quite rare, although a number of them are underway in the Pacific Northwest, for 

20
Table 3. Common factors to consider during project planning and design to increase success or 

effectiveness. (Modified from Roni et al. 2008.)

Category Common factors

Fish passage/barrier removal Project type (e.g., culvert type, bridge, fish ladder, dam removal), 

project design (slope, width, length, percent the culvert is countersunk), 

amount and quality of habitat above barrier, numbers of fish below 

barrier, width of stream crossing relative to floodplain

Instream structures Wood and boulder structures. Instream flow, water quality, riparian 

shade, sediment sources, structure design, channel erosion, structure 

type, previous level of instream structure, upstream processes (wood, 

water, sediment), intensity and magnitude of habitat improvement 

(number of structures and length of stream treated)

Gravel addition: amount and size of substrate added, frequency of 

addition, location of additions, instream flows, natural sediment supply, 

delivery, and transport

Off-channel/floodplain 

habitat

Level of connectivity (perennial vs. seasonal), water quality, instream 

flows, level of channel incision, restoration of natural flood regime, 

contaminants, upstream sediment, wood sources (riparian conditions), 

type of culvert or stream crossing

Riparian improvement Riparian silviculture: soil treatment, herbivore control, plant species, 

hydrology and instream flows, floodplain connection, water quality, 

invasive species

Grazing: livestock levels, width of buffer (fencing), upstream riparian 

shade and sediment, duration of grazing, season on grazing

Sediment reduction Forest roads: surface material, soil treatment, replanting (road removal 

projects), number of cross drain structures, stream crossing type, traffic 

levels and tire pressure, soil treatment and level of replanting (road 

removal projects)

Urban roads: water quality, level of impervious surface area, size of 

area treated, riparian conditions

Acquisition and protection Quality and quantity of habitat prior to acquisition, protection of habitat 

from other uses, invasive species, land use upstream and adjacent to 

site, inadequate assessment prior to purchase or protection

Flow augmentation Amount and timing of flows including minimum instream flow and 

flood flows, inadequate increase in instream flows, sediment and other 

water quality issues, length of stream reach impacted by flows, ability 

to control withdrawal by downstream users or plan for future water 

demands

example, ongoing basin-scale studies in the Entiat River, Potlatch River, Asotin Creek, Lemhi 

River, Bridge Creek, and lower Columbia River (Anderson, Mill, and Abernathy creeks). The 

earliest efforts to link habitat conditions to population-level fish response were in basin-scale 

forestry experiments, in which various logging practices were tested and their effects on salmon 

populations measured in subsequent years (e.g., Moring and Lantz 1975, Holtby and Scrivener 

1989). These studies tended to show that population-scale effects were relatively small, although 

in cases where habitat effects were severe (e.g., debris flows and dramatic increases in sediment 

21
supply), population declines were also significant (Hogan et al. 1998). We are aware of only a 

few studies reporting results of population-scale effects of habitat restoration on salmon, 

although there are several projects where the postrestoration monitoring period is just beginning 

and definitive results may not be available for a number of years. Among previous studies, the 

simplest actions are barrier removals, and a number of recolonization studies show dramatic 

population-level responses to reopening access to large amounts of habitat (Roni et al. 2008, Pess 

et al. 2012b). These studies clearly indicate that where habitat capacity has been reduced, 

restoring lost capacity results in relatively large and rapid population increases.

For other types of restoration actions, we are aware of only four published populationscale studies examining responses of coho salmon or steelhead populations to physical 

manipulation of habitats (Nickelson et al. 1992, Reeves et al. 1997, Solazzi et al. 2000, Slaney et 

al. 2003). Nickelson et al. (1992) and Reeves et al. (1997) produced inconclusive results, though 

large flood events and design issues appear to have limited the ability of the studies to detect a 

significant response. Slaney et al. (2003), which focused on nutrient additions, was never fully 

completed though initial results were mixed, showing increased juvenile steelhead growth but no 

improvement in survival or adult returns. In contrast, the Solazzi et al. (2000) study, perhaps the 

most robust and ambitious of the existing studies, demonstrated that creation of winter rearing 

habitat increased winter survival for coho salmon, as well as the number of smolts leaving the 

stream in spring. In these experiments, winter rearing area was increased by roughly 700% by 

construction of wood-formed pools and excavated alcoves, and overwinter survival and number 

of smolts increased by about 200%. Notably, the summer population increased by only 30–50%, 

indicating the importance of understanding which habitat/life stage is limiting and addressing 

that life stage through targeted restoration actions. For the Solazzi et al. (2000) study, basinwide habitat analysis had indicated that winter rearing habitat was limiting, restoration actions 

were designed to increase winter rearing habitat capacity, and the largest coho salmon response 

was in overwinter survival. In the Strait of Juan de Fuca IMW in northwestern Washington, the 

population abundance analyses have not yet been completed, but early results showed that 

increased pool area due to restoration activities may have increased coho salmon survival in the

treated watershed (Roni unpubl. data).

Six ongoing IMWs in the Columbia Basin have experimental designs that appear to be 

suitable for answering population-level questions (Entiat, Potlatch, Asotin, Lemhi, Bridge Creek, 

and Lower Columbia) (Figure 3). All six of these ongoing IMWs use some variation of the 

before-after control-impact (BACI) design, in which treatment and control watersheds are 

monitored before and after restoration. This design helps to control for natural variation in fish 

abundance and survival, and improves the ability to detect a salmon population response to 

restoration. Five of these basins appear to have sufficient pretreatment monitoring (Entiat, 

Potlatch, Asotin, Bridge Creek, and Lower Columbia), but most of the restoration actions in the 

Lemhi River were completed prior to monitoring, which means that most of the data collection 

will be after treatment only. To date, these IMWs do not have sufficient post-treatment 

monitoring to determine the effectiveness of suites of habitat restoration actions at the population 

or subpopulation scale, and most restoration actions were planned for implementation in 2012 or 

2013. Hence it is likely that changes in either habitat or fish populations at the watershed or 

population scale will not be statistically detectable until 2017 or later in most cases, assuming 

significant restoration effort occurred in 2012 or 2013. However, some early results at the 

project or reach scale indicate that restoration efforts to increase abundance and longevity of 

22
beaver dams, increase pools by constructing log jams, or reconnect isolated habitats (Bridge 

Creek, Entiat River, and Lemhi River, respectively) can locally increase salmonid abundance as 

expected. While each of these results appears promising, all of these studies require more years 

of monitoring to determine whether the restoration actions produce a population-level increase in 

abundance or productivity.

Figure 3. Map of IMWs and CHaMP (Columbia Habitat Monitoring Program) pilot watersheds in the 

Columbia River basin.

23
What Can Models Tell Us about 

Population Responses?

In the absence of empirical data showing population-level effects of restoration actions 

on salmon, modeling approaches can be used. For this purpose, modeling approaches require 

density and survival information specific to habitat types, and such information must be linked to 

information on habitat quality or quantity. That is, such models must be able to use estimated 

changes in habitat quantity and quality as a result of restoration actions, future land use, or 

climate change as inputs, and must be able to use the habitat-specific density and survival 

information to estimate the cumulative effect of multiple actions on the population. Here we 

describe two general model forms that can be used (stage-specific capacity models and life cycle 

models) and three broad types of analyses that have been done using these models (evaluation of 

restoration scenarios; evaluation of restoration scenarios and climate change; and evaluation of 

restoration scenarios, climate change, and future land use). While none of these models or 

analyses can substitute for measuring population responses, they can all help to set realistic 

expectations for restoration outcomes and help managers choose among alternative restoration 

scenarios.

Stage-Specific Capacity Models

Stage-specific capacity models and life cycle models differ primarily in how they link 

one life stage to the next. Stage-specific capacity models generally do not link life stages to each 

other or to adult returns. Rather, they estimate the spawning or rearing capacity of habitats at 

each life stage, then use uniform survival numbers from that life stage to the smolt stage to 

compare capacities among life stages (e.g., Reeves et al. 1989). These models can therefore be 

used to estimate which life stage limits population size, as well as how different types of 

restoration actions might influence population size (Beechie et al. 1994). However, stagespecific capacity models generally cannot be used to estimate survival improvements, because 

survival numbers are held constant in order to evaluate the effects of changing habitat capacity. 

In contrast, life cycle models mechanistically link life stages so that fish surviving one life stage 

enter the next life stage or else move downstream to alternative habitats (e.g., Moussalli and 

Hilborn 1986, Greene and Beechie 2004). Hence these models more realistically represent the 

sequence of life stages a population must experience and also allow variation in life history types 

to influence the outcomes of model runs. For example, if summer rearing habitats in mainstem 

rivers are at capacity, then some fish may simply migrate to the delta for summer rearing. 

Therefore, modeling of changes in one habitat may also influence density or survival in other 

habitats by altering the number of fish migrating into that habitat type.

Stage-specific capacity models are typically simple in form but very detailed in data 

needs. For example, the coho salmon stage-specific capacity model developed in the 1980s for 

estimating production potential of river basins produces a simple comparison of habitat 

24
capacities at four life stages, but it requires summing the areas of all individual habitat units (e.g., 

pools or riffles) measured or estimated throughout a river basin. Each habitat type has an 

associated density of juveniles it can support and an estimated survival from that stage to the 

smolt stage. Life stages and habitats incorporated into the model can include spawning, early 

rearing (spring), summer rearing, and winter rearing (Reeves et al. 1989). For each life stage, the 

area of each habitat type must be estimated in all channels and summed across the basin, then 

multiplied by density and survival to estimate the smolt production capacity of each habitat type. 

These estimates can then be compared among life stages to estimate which life stage limits the 

population.

These types of stage-specific capacity models can also be used to estimate habitat 

capacities for historical conditions to approximate the maximum potential smolt production of a 

basin, or to estimate habitat capacities for alternative restoration scenarios to tell managers which 

restoration options will likely yield the greatest improvement in a population. For instance, in 

the Skagit River and Stillaguamish River basins in Washington state, assessments of historical 

and current habitat capacities illustrated that winter-rearing habitats were likely limiting both 

historically and recently, but that in both basins the potential smolt production has been reduced 

by about 50% due to land uses (Beechie et al. 1994, 2001). Both assessments also illustrated that 

restoring overwintering habitats in floodplains and in beaver ponds were likely to be the most 

beneficial actions, and that restoring habitats impacted solely by forestry activities would likely 

yield a relatively small cumulative benefit, even if all forestry impacts were corrected.

The stage-specific capacity model has also been used to evaluate the relative potential 

effectiveness of alternative restoration scenarios, as in the recent analysis of potential Chinook 

salmon and steelhead rearing-capacity improvements that might be achieved by various 

restoration options in the Trinity River, California (Beechie et al. 2012). In that analysis, three 

types of restoration options were considered: in-channel restoration actions that improved rearing 

habitat quality and survival, increasing sinuosity of the main channel to increase rearing habitat 

quantity and capacity, and constructing off-channel habitats to increase rearing habitat quantity 

and capacity. The analysis illustrated that potential increases in Chinook salmon and steelhead 

carrying capacity range from 39% for a relatively realistic estimate of increasing habitat quality 

(more low velocity areas with cover) to 67% for a more optimistic scenario that increases both 

sinuosity and habitat quality (Figure 4). The most optimistic scenario, which increases habitat 

quality, increases sinuosity, and constructs tens of kilometers of side channels, more than 

doubles potential juvenile salmonid production. These types of quantitative predictions provide 

a frame of reference for benefits from restoration effort and can be used to inform measureable 

restoration goals.

Life Cycle Models

Life cycle models may take a number of forms, including statistical life cycle models, 

Leslie matrix models, and linked stock-recruit models. For the purposes of evaluating 

population-scale effects of habitat restoration, the latter two are potentially the most useful, as 

the statistical life cycle model is less suitable for incorporating restoration actions or scenarios 

into the model. That is, statistical life cycle models relate habitat variables at different life stages 

directly to a performance measure such as the return rate, but do not model habitat capacity at 

25
Figure 4. Estimated increases in juvenile Chinook salmon habitat carrying capacity, assuming an increase 

in habitat area and habitat quality by rehabilitation action in all reaches of 64 km of the Trinity 

River, from Lewiston Dam to the confluence of the North Fork Trinity River. (Modified from 

Beechie et al. 2012.)

each life stage or survival between life stages, and therefore are less able to incorporate 

restoration actions. By contrast, both Leslie matrix and linked stock-recruit models can use 

habitat data to drive estimates of capacities and survivals by life stage. However, the resolution 

of habitat data is typically much lower than in stage-specific capacity models, with habitat data 

typically estimated at the scale of reaches or subbasins rather than habitat units (e.g., Bartz et al. 

2006, Crozier et al. 2008). On the other hand, more types of habitat impacts and restoration 

actions have been incorporated into life cycle models, typically by evaluating functional 

relationships between land use, habitat conditions, and life stage capacity or survival outside the 

life cycle model (e.g., Bartz et al. 2006), then using those capacity and survival data to drive the 

life cycle model (e.g., Scheuerell et al. 2006). For example, analyses of land use effects on 

habitat characteristics in the Snohomish River basin indicated that fine sediment levels in 

spawning gravels are a function of forest road density, whereas prespawning temperatures are a 

function of riparian forest cover (Bartz et al. 2006). Hence modeling restoration scenarios that 

involve reduction of forest roads or increasing riparian forest cover produce changes in habitat 

characteristics (fine sediment or stream temperature). These habitat characteristics are then 

related to life stage survivals via a second set of functional relationships in which prespawning 

temperature influences fecundity (the number of eggs a female salmon produces) and fine 

sediment levels affect survival of eggs in the gravel (Scheuerell et al. 2006). Thus restoration 

actions are linked to salmon population responses via a series of linked functional relationships 

and modeling a restoration action produces a change in salmon population performance.

Regardless of model form, the utility of life cycle models is in their ability to predict 

outcomes of restoration. Some modeling efforts ignore the effects of climate change or future 

land use and simply evaluate the effects of restoration actions. Such analyses may examine a 

complex suite of land use impacts on habitat conditions, such as the effects of erosion on the 

quantity of fine sediments in spawning gravels, the effects of riparian conditions on stream 

26
temperature or wood and pool abundance, the impacts of unscreened water diversions, or land 

cover influences on peak flows (e.g., Bartz et al. 2006, Walters et al. 2012). Each of the 

response variables are known to affect capacity or survival of salmon. Fine sediments affect egg 

incubation and survival to emergence from spawning gravels, wood and pool abundance affect 

spawning or rearing capacity, and stream temperature can influence egg incubation, summer 

rearing survival, or spawning or emergence timing. Each of these effects requires a functional 

relationship (i.e., a mathematical equation representing the relationship between the habitat 

variable and salmon capacity or survival) in order to influence the life cycle model outcome, 

relating habitat or restoration actions to habitat response, and relating habitat response to fish 

response (Scheuerell et al. 2006). Once all of these relationships have been assembled, the 

model can be constructed and used to evaluate alternative restoration scenarios. For example, 

Scheuerell et al. (2006) compared restoring spawning habitat, rearing habitat, or both in the 

estuary, main stem, lowland tributaries, or headwaters, and found that restoring rearing habitats 

in the estuary and main stem would yield the largest improvement in spawner abundance. Such 

analyses can help prioritize restoration actions and set realistic expectations for restoration 

outcomes (Beechie et al. 2010).

Life cycle models are also useful for evaluating the potential effects of climate change on 

salmon population performance, as well as the effects of future land uses. Examples of using life 

cycle models to analyze potential effects of climate change on salmonids include predicting 

effects of climate change on multiple populations to show that populations occupying different 

streams will likely respond differently to climate change (Crozier and Zabel 2006, Crozier et al. 

2008), or to show that population-level effects of restoration actions are partially negated by 

climate change (e.g., Battin et al. 2007) (Figure 5). Finally, life cycle models have also 

incorporated future land use effects into analyses of restoration effectiveness, showing that while 

land use trends and climate change may tend to decrease population size in some areas, 

restoration actions can still overcome those negative effects and result in population increases 

into the future (Figure 5).

Figure 5. Estimated change in Chinook salmon population size with varying restoration scenarios and 

climate change. “Current path” represents limited restoration plus continued land use change into 

the future. The climate change scenario is the moderate A1B emissions scenario. (Adapted from 

Battin et al. 2007.)

27
Summary and Conclusions

Decades of fish-habitat relationship research have demonstrated the importance of 

freshwater and estuarine habitat for various life stages of Pacific salmon. Moreover, research has 

shown the negative impacts of human actions on habitat quality and localized salmon carrying 

capacity, growth, and life history diversity. More recently, efforts have focused on quantifying 

effectiveness of different restoration techniques. Many studies have reported improvements in 

physical habitat, particularly at a reach scale for various techniques. Fewer studies have 

quantified biological responses, but several have shown localized (reach scale) increases in fish 

abundance for placement of instream structures and reconnection of both tributary and floodplain 

habitat. Also, few of these studies have explicitly examined changes in salmon or steelhead 

survival. Less information exists for other techniques and additional research is needed to 

quantify changes in fish survival and abundance due to restoration at reach and watershed scales.

Scaling these reach-scale effects up to the watershed or population scale requires either 

watershed or population evaluation or salmonid life cycle modeling. Several IMW studies are 

underway to quantify population-level responses to restoration and quantify the effects of 

multiple restoration techniques throughout a watershed on salmon survival and production. 

Initial results from these studies are promising; however, results will not be available for most of 

these studies for 5 or more years and results may not be directly transferable to other populations 

and watersheds. Until these studies are completed, predicting population-level responses to 

habitat change can be estimated with statistical/computer models. These include two general 

categories: 1) limiting-factors models based on habitat capacity, and 2) life cycle models that 

account for survival and abundance at each life stage. While modeling approaches are useful, 

there is much uncertainty in all models, and quantifying this uncertainty with Monte Carlo 

simulations and sensitivity analysis can provide useful information to managers. No one model 

will address all needs for estimating restoration benefits and priorities; multiple models are 

needed. Models are population specific due to unique characteristics of each watershed and 

population, so applying findings from one watershed or population to another should be done 

with caution and account for differences in habitat and population characteristics between basins. 

In addition, models that directly incorporate data from the subject watershed or population 

should generally be given more weight than models based on extrapolations from other basins.

28
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rearing habitat on abundance of salmonids in two coastal Oregon streams. Can. J. Fish. Aquat. 

Sci. 57:906–914.

Sommer, T. R., M. L. Nobriga, W. C. Harrell, M. Batham, and W. Kimmerer. 2001. Floodplain rearing 

of juvenile Chinook salmon: Evidence of enhanced growth and survival. Can. J. Fish. Aquat. Sci.

58(2):325–333.

Southwood, T. R. E. 1977. Habitat, the template for ecological strategies? J. Anim. Ecol. 46:337–365.

Spence, B. C., G. A Lomnicky, R.M. Hughes, and R. P. Novitzki. 1996. An ecosystem approach to 

salmonid conservation. TR-4501-96-6067. ManTech, Corvallis, OR.

Stalnaker, C. B., B. L. Lamb, J. Henriksen, K. Bovee, and J. Bartholow. 1995. The instream flow 

incremental methodology: A primer for IFIM. USGS Biological Rep. 29. U.S. Geological 

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Stanley, E. H., M. J. Catalano, N. Mercado-Silva, and C. H. Orr. 2007. Effects of dam removal on brook 

trout in a Wisconsin stream. River Res. Appl. 23(7):792–798.

39
Taylor, E. B. 1990. Environmental correlates of life history variation in juvenile Chinook salmon, 

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_annual_progress_rpt.pdf [accessed 01 November 2013].

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Vought, L. B. M., and J. O. Locoursiere. 2010. Restoration of streams in the agricultural landscape. In

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Walters, A. W., D. M. Holzer, J. R. Faulkner, C. Warren, P. D. Murphy, and M. M. McClure. 2012. 

Quantifying cumulative entrainment effects for Chinook salmon in a heavily irrigated watershed. 

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40
41

Appendix A: Lists of All the Literature Examined 

with Summaries of Key Findings

Key findings are listed for 409 published studies we located that report effectiveness of different restoration techniques. The 

seven categories under headings below are fish passage/barrier removal (22 references), instream structures (209 references), offchannel/floodplain habitat (82 references), riparian/grazing (53 references), sediment/roads (27 references), acquisition and protection 

(1 reference), and flow (15 references). In each of the following seven lists for these categories, the left column provides the 

document reference and the right column summarizes the key quantitative findings. In cases where no numeric or quantitative 

information was reported for fish or habitat, we indicate this as “no numbers” reported. Within each category, the publications are 

listed alphabetically by author.

Fish Passage/Barrier Removal References (Subtotal is 22 of 409)

Reference Key Quantitative Findings

Born, S. M., K. D. Genskow, et al. 1998. 

Socioeconomic and institutional dimensions 

of dam removals: The Wisconsin experience. 

Environ. Manag. 22(3):359–370.

Financial and social survey, no physical data, just “opinion survey” on impacts 

and benefits.

Bushaw-Newton, K. L., D. D. Hart, et al. 2002. 

An integrative approach towards 

understanding ecological responses to dam 

removal: The Manatawny Creek study. J. 

Am. Water Resour. Assoc. 38(6):1581–1599.

Channel changes in former impoundment = 0.5 m decrease in elevation above 

dam, water quality = no change, invertebrates = dominant assemblage changed 

from lentic to lotic but no other changes, channel changes downstream of dam = 

0.5 m aggradation, fish assemblage = none downstream of dam, fish assemblage 

in former reservoir = change before and after.

Doyle, M. W., E. H. Stanley, et al. 2003. 

Channel adjustments following two dam 

removals in Wisconsin. Water Resour. Bull. 

39(1):1011–1026.

Physical = total suspended solids increased downstream of dam following 

removal, 7.8% and 15.4% of sediment eroded from reservoirs in first year (they 

looked at two dams removals), change in channel cross sections above and below 

dams, increased fine sediment below dams.
42

FAO/DVWK. 2002. Fish passes: Design, 

dimensions and monitoring. FAO, Rome.

Provides only general information on success of different fish passes, no specific 

numbers.

Glen, D. I. 2002. Recovery of salmon and trout 

following habitat enhancement works: Review 

of case studies 1995–2002. In Proceedings of 

the 13th International Salmonid Habitat 

Enhancement Workshop, Hotel Westport, 

Mayo, Ireland, 16–19 September 2002, p. 93–

112. Central Fisheries Board, Dublin, Ireland.

Removal of culverts, Wauchope Burn and other Scottish streams. Salmon fry 

found upstream of former culvert immediately after removal and numbers went 

from 0 before removal in 2000 to a mean of .35/m2 in 2001 and .20/m2 in 2002.

Grzybkowska, M., J. Hejduk, et al. 1990. 

Seasonal dynamics and production of 

Chironomidae in a large lowland river 

upstream and downstream from a new 

reservoir in central Poland. Archiv Fur 

Hydrobiologie 119(4):439–455.

Actually this is not dam removal, but a recently constructed dam—no difference 

in density or production of macroinvertebrates, but percent collectors higher 

above dam than below (25.1% vs. 1% below).

Hart, D. D., T. E. Johnson, et al. 2002. Dam 

removal: Challenges and opportunities for 

ecological research and river restoration. 

Bioscience 8:669–682.

Review article with large table summarizing results of 20 dam removals and 30 

papers, generalizations without specifics. In general, increased fish migration, 

sediment transport, changes in nutrients and water quality (typically initial 

decrease), and change in fish and macroinvertebrate community.

Hill, M. J., E. A. Long, et al. 1994. Effects of 

dam removal on Dead Lake, Chipola River, 

Florida. Proc. Annu. Conf. Southeastern 

Assoc. Fish Wildl. Agencies 48:512–523.

Increase in largemouth bass, water quality, and species diversity.

Kanehl, P. D., J. Lyons, et al. 1997. Changes 

in the habitat and fish community of the 

Milwaukee River, Wisconsin, following 

removal of the Woolen Mills Dam. N. Am. J. 

Fish. Manag. 17(2):387–400.

Increased smallmouth bass abundance and biomass, “good” fish Index of 

Biological Integrity (IBI), and decrease in carp upstream of dam. Initial decrease 

in smallmouth bass and lower quality fish IBI downstream of dam, but rebounded 

to preproject levels by 5 years after dam removal.
43

Kiffney, P. M., G. R. Pess, et al. 2009. Changes 

in fish communities following recolonization 

of the Cedar River, WA, USA by Pacific 

salmon after 103 years of local extirpation. 

River Res. Appl. 25(4):438–452. Online at 

http://dx.doi.org [DOI name 10.1002/rra.1174, 

accessed 12 December 2013].

Coho salmon, Chinook salmon, cutthroat trout, rainbow trout. Before the ladder, 

late summer total salmonid (trout only) density increased with distance from the 

dam. This pattern was reversed after the ladder was opened, as total salmonid 

density (salmon and trout) approximately doubled in the three reaches closest to 

the dam. A nearby source population, dispersal by adults and juveniles, low 

density of resident trout, and high quality habitat above the barrier likely 

promoted rapid colonization.

Lenhart, C. F. 2003. A preliminary review of 

NOAA’s community-based dam removal and 

fish passage projects. Coastal Manag. 

31(1):79–98.

Looked at 18 NOAA community-based restoration program dam removals. Only 

reported general results—increased passage for river herring (Alosa spp.) and 

salmonids (Oncorhynchus spp.).

Martens, K. D., and P. J. Connolly. 2010. 

Effectiveness of a redesigned water diversion 

using rock vortex weirs to enhance 

longitudinal connectivity for small salmonids. 

N. Am. J. Fish. Manag. 30(6):1544–1552.

Juvenile Chinook salmon, juvenile coho salmon, juvenile steelhead, rainbow 

trout, and mountain whitefish. Dam-style water diversions were replaced with 

rock weirs allowing fish passage. There was a new appearance of Chinook, coho 

and mountain whitefish upstream of the weirs. Using PIT tags, 109 upstream 

passage events by small salmonids were recorded. Eighty-one percent of those 

events were rainbow or steelhead. Small rainbow or steelhead ranging 86–238 

mm were able to pass.

Nelson, J. E., and P. Pajak. 1990. Fish habitat 

restoration following dam removal on a warmwater river. American Fisheries Society, 

North Central Division, Rivers and Streams 

Technical Committee Symposium 

proceedings: The restoration of midwestern 

stream habitat, Minneapolis, MN. American 

Fisheries Society, Bethesda, MD.

Habitat Suitability Index values for smallmouth bass increased following dam 

removal and channel restoration. On average, the index increased by 0.29 or a 

39.5% increase.
44

Pearson, A. J., N. P. Snyder, et al. 2011. Rates 

and processes of channel response to dam 

removal with a sand-filled impoundment. 

Water Resour. Res. 47(08). Online at 

http://dx.doi.org [DOI name 10.1029/2010 

WR009733, accessed 12 December 2013].

No fish. After dam removal, initial channel development and sediment erosion 

occurs rapidly (weeks to months) in sand-filled impoundments, but excavation of 

the remaining sediment occurs more slowly, depending on vegetation feedbacks 

and flood events.

Price, D. M., T. Quinn, et al. 2010. Fish 

passage effectiveness of recently constructed 

road crossing culverts in the Puget Sound 

region of Washington state. N. Am. J. Fish. 

Manag. 30:1110–1125.

Evaluated fish passage at 77 permitted culverts. Of those studied, 30% were in 

fact barriers. Those permitted as no-slope or as an unknown design type were 

barriers in 45% of the cases. Most failures were due to noncompliance with 

permit provisions, particularly culvert slope and a lack of critical evaluation of 

proposed plans in the context of site conditions. No species listed.

Sethi, S. A., A. R. Selle, et al. 2004. Response 

of Unionid mussels to dam removal in 

Koshkonong Creek, Wisconsin (USA). 

Hydrobiologia 525:1–3.

Density of mussels downstream of dam decreased by 1.2 mussels/m2 and silt and 

sand increased from 17.9% to 46.3% of total area sampled.

Shafroth, P. B., J. M. Friedman, et al. 2002. 

Potential responses of riparian vegetation to 

dam removal. Bioscience 52(8):703–712.

This is a review article discussing potential changes in riparian vegetation

following dam removal. No specifics provided.

Smith, L. W., E. Dittmer, et al. 2000. Breaching 

of a small irrigation dam in Oregon: A case 

history. N. Am. J. Fish. Manag. 20(1):205–

219.

Mostly a review of sociological aspects including stakeholder input and 

expectations. They report increased fish passage, but provide no data.

Stanley, E. H., M. J. Catalano, et al. 2007. 

Effects of dam removal on brook trout in a 

Wisconsin stream. River Res. Appl. 

23(7):792–798.

Brook trout. No numbers. No new species colonized the creek in the 2 years 

after dam removal. Catch per unit effort (CPUE) was lower and young-of-theyear CPUE was higher in 2005 than in 2001 in all reaches, but the magnitude of 

the changes was substantially larger in the two dam-affected sample reaches 

relative to an upstream reference reach, indicating a localized effect of the 

removal. Total length of adults and young-of-the-year and the adult body 

condition did not vary between years or among reaches.
45

Stanley, E. H., M. A. Luebke, et al. 2002. 

Short-term changes in channel form and 

macroinvertebrate communities following 

low-head dam removal. J. North Am. 

Benthol. Soc. 21(1):172–187.

Physical—decrease in cross-sectional area above dam (59 m2 to 11 m2), 

macroinvertebrate assemblage changed to lotic taxa, but following removal no 

difference in taxa between upstream and downstream reaches.

Tetra Tech. 2010. Reach-scale effectiveness 

monitoring program. 2009 annual progress 

report. Tetra Tech EC Inc., Bothell, WA. 

Online at http://www.rco.wa.gov/documents/

monitoring/2009_annual_progress_rpt.pdf 

[accessed 01 November 2013].

Using various indicators established by NOAA, monitored eight diversion 

screening projects 1 and 2 years after installation and found 80% of measured 

indicators were in compliance with NOAA targets. Note that they also reported 

on preliminary results of floodplain, fencing, and instream habitat improvement 

projects.

Walters, A. W., D. M. Holzer, et al. 2012. 

Quantifying cumulative entrainment effects 

for Chinook salmon in a heavily irrigated 

watershed. Trans. Am. Fish. Soc. 

141(5):1180–1190.

Chinook salmon. Under median-streamflow conditions with unscreened 

diversions, the estimated cumulative effect of the diversions was a loss of 71.1% 

of outmigrating smolts due to entrainment. Estimated mortality was reduced to 

1.9% when all diversions were screened. Mortality dropped to between 1% and 

4% for screened diversions for all streamflow conditions. If resources are 

limited, targeting the diversions that remove a large amount of water and 

diversions in locations with high fish encounter rates is most effective.
46

Instream Structure References (Subtotal is 209 of 409)

Reference Key Quantitative Findings

Aitken, W. W. 1935. Iowa stream improvement 

work. Trans. Am. Fish. Soc. 65:322–323.

Log structures. No numbers. Tree planting hinders and eventually practically 

eliminates bank erosion, shade will be produced, vegetation will take hold, cover 

will be provided, food organisms will increase and benefit fish, and water 

temperature will be more stable. The log and rock crib deflectors are effective if 

located in streams where current will be forced against ledge rocks or boulderstrewn banks. Reforestation and erosion control should come first, then bank 

protection by plantings and by mechanical means, and finally actual installation 

of stream improvement devices.

Albertson, L. K., B. J. Cardinale, et al. 2011. 

Impacts of channel reconstruction on 

invertebrate assemblages in a restored river. 

Restor. Ecol. 19(5):627–638.

Invertebrate abundance and biomass were lower in the restored reach and there 

was a shift from dominance by filter-feeding caddis flies to grazing mayflies. 

Average densities declined 19%. Species richness and evenness were higher in 

the restored reach. Abundance declined nearly 50% in heterogeneous substrate 

treatments compared to homogeneous treatments. Biomass declined 65% from 

heterogeneous treatments to homogeneous treatments.

Aldridge, K. T., J. D. Brookes, et al. 2009. 

Rehabilitation of stream ecosystem functions 

through the reintroduction of coarse 

particulate organic matter. Restor. Ecol.

17(1):97–106.

Reintroduction of coarse particulate organic matter in the form of leaf litter. 

Before addition, there was no difference in community respiration, but control 

reaches retained 6.8% more filterable reactive phosphorus than treatment reaches. 

After addition, community respiration was greater in the treatment reaches and 

7.7% more filterable reactive phosphorus was retained than in control reaches.

Anderson, J. W. 1981. Anadromous fish 

projects 1981 USDI-BLM Coos Bay District. 

In T. J. Hassler (ed.), Proceedings: 

Propagation, Enhancement, and Rehabilitation 

of Anadromous Salmonid Populations and 

Habitat in the Pacific Northwest Symposium, 

p. 109–114. Humboldt State Univ., Arcata, 

CA.

No numbers. Constructed gabions function well and have been used extensively 

by anadromous fish for spawning. Chinook salmon, coho salmon, winter 

steelhead, cutthroat trout, and Pacific lamprey use the structures that have trapped 

spawning gravels and created rearing pools. Scour pools have developed while 

extensive beds of gravel for aquatic organism production and adult salmonid 

spawning have been deposited.
47

Angermeier, P. L., and J. R. Karr. 1984. 

Relationship between woody debris and fish 

habitat in a small warm-water stream. Trans. 

Am. Fish. Soc. 113:716–726.

Wood addition. Fish and benthic invertebrates were usually more abundant on 

the side with debris. Artificial debris was colonized by many invertebrates. They

were 3.9 times more abundant on the debris side in July and 5.7 times more 

abundant on the debris side in September. Most large fish (age 2+) avoided 

reaches without debris, whereas some smaller fish preferred them. Fish’s 

association with woody debris appeared more closely related to camouflage than 

to increased food availability or protection from strong currents.

Armantrout, N. B. 1991. Restructuring streams 

for anadromous salmonids. In J. Colt and R. 

J. White (eds.), Fisheries bioengineering, 

Symposium 10, p. 136–149. American 

Fisheries Society, Bethesda, MD.

Added large woody debris, rock, and gabions. Of the 396 structures, 85% were 

completely or partially intact and in place and improving aquatic habitat. Where 

most structures are located, pool habitat increased from 40% to 48%, riffles 

decreased by 5.5% and glides by 5.3%. The percentage of substrate as exposed 

bedrock decreased from 33% to 20%; rubble, sand, and silt showed the greatest 

percentage increase. Beavers built dams on top of 22 structures. Measurements 

of existing fish communities were limited. Preliminary results showed that 

juvenile fish used structures for overwintering. During the summer, juvenile 

salmonids are visible in pools, glides, and other quieter waters or shallow riffles. 

Juvenile populations increased where pools and other habitats increased. Coho

salmon, steelhead, and cutthroat trout used undercut banks, root masses, and 

woody debris in pools behind structures for winter habitat.

Avery, E. L. 1996. Evaluations of sediment 

traps and artificial gravel riffles constructed to 

improve reproduction of trout in three 

Wisconsin streams. N. Am. J. Fish. Manag.

16:282–293.

Riffle construction and sediment trap installation. The amount of gravel substrate 

did not increase significantly in any treatment streams, although the sand dunes 

appeared to decline in all streams. No evidence that installation of sediment traps 

and gravel riffle solve deficiencies in juvenile trout recruitment where sand is the 

natural and prevailing parent material and there is no prior record of successful 

spawning.
48

Avery, E. L. 2004. A compendium of 58 trout 

stream habitat development evaluations in 

Wisconsin—1985–2000. Wisconsin Dept. 

Natural Resources, Bureau of Integrated 

Science Services, Waupaca, WI.

Large woody debris, boulders, beaver, and brush removal. The success of each 

project was judged on the basis of the percent change within a treatment zone for 

four categories (or population variables): 1) total number of trout, 2) number of 

trout ≥6′′, 3) number of legal size trout, and 4) total biomass (pounds per mile). 

Standardization was at a “per mile” basis. Two levels of success were 

determined: Level 1 = postdevelopment increases in the population variable of 

25% or more and Level 2 = increases in the population variable of 50% or more. 

Approximately 59% of the changes in 140 population variables analyzed had 

Level 1 success after habitat development; 50% had Level 2 success. Total 

abundance of trout met Level 1 success in 43% of the treatment zones. Success 

rate at Level 2 was found in 31% of the treatment zones. Abundance of legal size 

trout achieved success rates of 65% and 62% at Levels 1 and 2, respectively. In 

treatment zones with allopatric populations of brook trout or brown trout, success 

rates were similar. In sympatric populations, brown trout responded much more 

positively than brook trout did to habitat development. Average empirical 

postdevelopment changes for populations of trout in 58 treatment zones included 

a 13% decline in total abundance of trout (from 1,323 per mile to 1,125 per mile), 

a 65% increase in trout ≥6′′ (from 208 per mile to 344 per mile), a 25% increase 

in legal-size trout (from 291 per mile to 363 per mile), and a 63% increase in 

biomass (from 100 lb trout per mile to 163 lb trout per mile).

Baldigo, B. P., A. S. G. Ernst, et al. 2008. 

Restoring geomorphic stability and 

biodiversity in streams of the Catskill 

Mountains, New York, USA. In J. Nielsen, 

J. J. Dodson, et al. (eds.), Reconciling 

fisheries with conservation, Symposium 49(2), 

p. 1777–1790. American Fisheries Society, 

Bethesda, MD.

Relative fish species richness, total biomass, and biomass equitability increased 

significantly after restoration. The relative response of fish-community density at 

treatment reaches was slight negative. Biomass differentials increased 

significantly on average by 5.32 g/m2 after restoration, mean biomass differentials 

differed slightly among the streams, and the response of biomass to restoration 

differed across the three streams.
49

Baldigo, B. P., A. S. G. Ernst, et al. 2010. 

Variable responses of fish assemblages, 

habitat, and stability to natural-channel-design 

restoration in Catskill Mountain streams.

Trans. Am. Fish. Soc. 139(2):449–467.

Significant increases in community richness (30%), diversity (40%), species or 

biomass equitability (32%), and total biomass (up to 52%) was found in at least 

four of the six restored reaches. Bank stability, stream habitat, and trout habitat 

suitability indices generally improved significantly at the restored reaches, but 

key habitat features and trout habitat suitability indices did not change or 

decreased at two of the sites.

Baldigo, B. P., D. R. Warren, et al. 2008. 

Response of fish populations to natural 

channel design restoration in streams of the 

Catskill Mountains, New York. N. Am. J. 

Fish. Manag. 28(3):954–969.

The habitat suitability indexes for all salmonid species increased by 15% on 

average (brook, brown, and rainbow trout). The net increase in the number of 

species was significant (34%) after restoration. Net increase in density of fish 

averaged 0.16 fish/m2 (a 253% increase) after restoration. Net increase in 

biomass was significant and averaged 3.65 g/m2 (a 239% increase) after 

restoration. Brown trout density increased 206% and biomass 253%.

Banchetti, R., N. Ceccopieri, et al. 2004. 

Valutazione della qualità delle acque del 

fiume Frigido (Totcana) mediante l’indice 

I.B.E. (Indice Biotico Esteso). [Assessment of 

the quality of waters of the Frigido river 

(Tuscany) by means of the index I.B.E. 

(Extended Biotic Index)]. Atti della Società 

Toscana di Scienze Naturali, Memorie Serie B

111:55–64.

In Italian. Examined effects of sediment reduction through 1) reduced discharge 

of sediment from marble works, and 2) physical cleaning of several kilometers of 

stream to remove fine sediment (marble) from substrate (removed tens of 

thousands of metric tons, exact number not provided). Measured IBE, a 

macroinvertebrate-based metric developed for Italian streams, following new 

regulations and restoration measures. IBE improved from Class III and IV to 

Class I or II in middle reaches of River Frigido by year 2000. However, lower 

urbanized/channelized reaches in city of Massa still remain Class IV (polluted or 

altered) and V (severely polluted or altered), in part due to water extraction and 

other industrial and civic discharge believed to be impacting water quality in 

these lower reaches (lower ≈2–3 km are Class V).

Barrineau, C. E., W. A. Hubert, et al. 2005. 

Winter ice processes and pool habitat 

associated with two types of constructed 

instream structures. N. Am. J. Fish. Manag.

25(3):1022–1033.

Pools associated with instream structures provided habitat for trout in the fall, but 

ice processes from fall through winter affected habitat in many of the pools. The 

forming, dissipation, and reforming of ice features, such as hanging dams, anchor 

ice, and surface ice, affected the volume of pool habitat available. Trout were 

observed in these pools in the fall, but tended to abandon pools with variation in 

ice formations as winter progresses. Small influxes of groundwater in the study 

reach affected both the magnitude and frequency of ice formations and pool 

habitat.
50

Bates, D. J., G. G. McBain, et al. 1997. 

Restoration of a channelized salmonid stream, 

Oullette Creek, British Columbia. In J. D. 

Hall, P. A. Bisson, et al. (eds.), Symposium on 

sea-run cutthroat trout: Biology, management, 

and future conservation. American Fisheries 

Society, Oregon chapter, Corvallis.

Abstract of a poster. Rock weirs built to duplicate natural riffles and pools. 

Result has been the collection of spawning gravel on the upstream edge of riffles 

and increased areas in pools for rearing. The restored areas are stabilizing, 

providing a significant increase in rearing habitat for both coho salmon and 

cutthroat trout.

Beschta, R. L., W. S. Platts, et al. 1994. 

Artificial stream restoration—money well 

spent or expensive failure? In Proceedings, 

environmental restoration, UCOWR 1994 

Annual Meeting, Big Sky, MT., August 2–5, 

1994, p. 76–104. Universities Council on 

Water Resources, Southern Illinois Univ.

Carbondale.

Wood and rock. Several case studies. Despite large restoration effort, no species 

of salmon had a significant increase trend. Number of coho salmon produced in 

the creek was the lowest since smolt trapping began. No Chinook salmon were 

observed despite better fish passage. The habitat manipulation had not 

significantly increased the production of anadromous fish; in some situations, the 

presence of in-channel structures continued to maintain factors limiting habitat 

productivity; despite seeding and passage over falls, the project was unsuccessful,

since adult Chinook still have not migrated beyond the falls. Channel 

realignment, bank modification, and planting of riparian vegetation produced no 

benefits, as Chinook salmon and steelhead parr densities were 1/10th to 1/5th 

those of the control streams. Log structures, rock structures, boulder placement,

and current deflectors resulted in no significant differences between treatments 

and controls of parr densities for any class of steelhead or Chinook. Ungrazed 

stream reaches inside exclosure were narrower and deeper than the grazed stream 

reaches and pool quality was consistently higher within the ungrazed reach, but 

rainbow and cutthroat trout populations did not reflect difference in habitat 

conditions between the two reaches. Heavy channel and bank alterations show no 

young-of-the-year trout response to additions of large amounts of gravel. 

Juvenile and adult age groups did not respond to channel alterations that 

supposedly provided deepwater habitat and object cover.
51

Binns, N. A. 1994. Long-term responses of 

trout and macrohabitats to habitat 

management in a Wyoming headwater stream.

N. Am. J. Fish. Manag. 14:87–98.

Large woody debris and boulders. Stream developed a narrower channel with 

deep pools that helped brook trout survive low flows. After 7 years, brook trout 

6′′ and longer had increased 1.814%, brook trout less than 6′′ increased 1.462%, 

and the total population density had reached 2,074/mi (268 lb/acre). This 

dropped to 222/mi (41 lb/acre) after an extended drought, but this level was 90% 

better than before habitat development.

Binns, N. A. 1999. A compendium of trout 

stream habitat improvement projects done by 

the Wyoming Game and Fish Department, 

1953–1998. Wyoming Game and Fish Dept., 

Fish Division, Cheyenne.

Compendium of 60+ case studies. For the 89 trout population indices analyzed at 

the 30 projects containing only wild trout, statewide trout population response 

after habitat improvement was positive. Funds invested in habitat development 

gave a satisfactory return (wild trout and streams with a mix of wild and stocked). 

Eighty-one percent of the 89 wild trout abundance and biomass indices had a 

percent change increase of 25% or greater (Level 1). Rate of success was 50% or 

greater (Level 2) for 74% of the indices. Rate of success for 139 population 

indices at projects containing both wild and stocked trout was 83% at Level 1, 

and no less than 72% for Level 2. Success rates for wild trout/mile were 

generally less at streams of higher order. Averaged over all projects, posttreatment abundance of wild trout of all sizes increased 310% and biomass 271%. 

Catchable (6′′ or greater) wild trout numbers increased 192% and their biomass 

was up 146%. For instream structures, best trout response was at plunges (363% 

gain), but revetments (129% gain), tree jams (69% gain), and rock weirs (66% 

gain) also increased trout numbers. Both log and timber plunges exceeded 

minimum residual pool depth (RPD) criteria, but log plunges (RPD 1.85 ft) were 

better than either timber plunges (RPD 1.6 ft) or rock plunges (RPD 1.35 ft).

Binns, N. A. 2004. Effectiveness of habitat 

manipulation for wild salmonids in Wyoming 

streams. N. Am. J. Fish. Manag. 24:911–921.

Boulders, large woody debris. Summary of 30+ projects. Abundance and 

biomass of trout increased following habitat manipulation among most of the 

projects. Both mean abundance (105%) and biomass (124%) for total trout 

increased post-treatment and were significantly higher than pretreatment levels. 

Mean catchable trout numbers (77%) and biomass (62%) also increased 

significantly. Cover for trout and residual pool depth significantly increased 

following projects, whereas eroding banks significantly decreased. Both timber 

and log check dams consistently produced good pools, but rock check dams did 

not.
52

Biron, P. M., C. Robson, et al. 2004. Deflector 

designs for fish habitat restoration. Environ. 

Manag. 33(1):25–35.

Compared various deflectors. Results showed a 26–30% smaller scour depth 

resulting from 45° deflectors than from 90° deflectors. The volume of scour and 

the potential for bank erosion were greater when flow was under the height of the 

deflectors rather than overtopping and when the length of deflector was increased. 

When flow was under the deflector height, 135° deflectors had the highest 

amount of bank erosion, whereas during overtopping flow conditions, 90° 

deflectors had the greatest bank erosion potential.

Black, R. W., and T. A. Crowl. 1995. Effects of 

instream woody debris and complexity on the 

aquatic community in a high mountain, desert 

stream community. In D. A. Hendrickson 

(ed.), Annual symposium of the Desert Fishes 

Council, Furnace Creek, California, p. 61.

Abstract only. Conference proceedings. Large woody debris. No numbers.

Manipulated woody debris resulting in significant changes in trout densities and 

physical characteristics. Trout prey electivity (Chesson’s) and capture efficiency 

were directly related to habitat complexity. Macroinvertebrate densities did not 

respond as significantly to changes in habitat complexity as trout densities. The 

invertebrates appeared to be limited by primary productivity rather than habitat 

complexity. Habitat complexity was subsequently decreased by a high spring 

runoff that lowered significance of responses.

Blakely, T. J., J. S. Harding, et al. 2006. 

Barriers to the recovery of aquatic insect 

communities in urban streams. Freshw. Biol.

51:1634–1645.

Boulder placement. Adult caddisfly diversity and abundance was greater 

downstream than upstream. Numbers of caddisflies caught declines upstream and 

about 2.5 times more individuals were taken in traps immediately below than 

above five culverts. Bridges had no significant effect on the size of catches made 

above or below them.

Bond, N. R., and P. S. Lake. 2005. Ecological 

restoration and large-scale ecological 

disturbance: The effects of drought on the 

response by fish to a habitat restoration 

experiment. Restor. Ecol. 13(1):39–48.

Added wood due to sediment. Observed short-term increases in the abundance of 

mountain galaxias at the four-structure sites, while both the four-structure and the 

one-structure treatments appeared to buffer against drought-induced declines in 

two other species. Drought eventually caused the loss of all fish. Beneficial 

wood is contingent on permanency of flow.
53

Bond, N. R., S. Sabater, et al. 2006. 

Colonisation of introduced timber by algae 

and invertebrates, and its potential role in 

aquatic ecosystem restoration. Hydrobiologia 

556:303–316.

Added large woody debris. Colonization of algae was rapid with distinct changes 

in the assemblages over the first 4 weeks. Thereafter changes were less marked. 

There were differences in nutrient concentrations and some measures of algal 

abundance. Invertebrates colonized the wood extremely rapidly, peaking in 

abundance and richness in 8 weeks. Invertebrate abundances closely tracked 

changes in abundance of algae. By 20 weeks, there were sharp decreases in 

invertebrate and algal abundances and invertebrate species richness. The added 

timber quickly created habitat with high levels of primary production in an 

otherwise heterotrophic stream system.

Boreman, J. 1974. Effects of stream 

improvement on juvenile rainbow trout in 

Cayuga Inlet, New York. Trans. Am. Fish. 

Soc. 103:637–641.

Log structures. There was no difference in biomass, average weight, or number

of rainbow trout between structured and control sections. No differences existed 

among biomass, average weight, or numbers of sculpin or minnows in bank crib 

and control sections. However, sculpin in pool digger sections were smaller in 

biomass, average weight, and number in the above-pool sections. Sculpin

biomass and number were greater in pool subsections of the pool diggers when 

compared to the above-pool subsections. Trout comprised a significantly greater 

percent of the total biomass in the crib sections than pool digger sections (66% 

vs. 48%).

Boussu, M. F. 1954. Relationship between 

trout populations and cover on a small stream. 

J. Wildl. Manag. 18(2):229–239.

Rainbow trout, eastern brook trout, and brown trout. The increase in total pounds 

of fish following application of brush cover amounted to 258.1%. The three 

sections that were unaltered increased an average of 22.5%. There was an 

average increase in legally catchable fish of 0.62 lb per inventory per 100 square 

feet of cover applied. The total pounds decreased 40.5% in the sections where 

cover was removed. Legal fish decreased an average of 0.95 lb per inventory per 

100 square feet of brush cover removed. It was noted that aquatic vegetation was 

of value as cover when rooted to the stream bottom and also while free-floating.
54

Brittain, J. E., J. A. Eie, et al. 1993. 

Improvement of fish habitat in a Norwegian 

River channelization scheme. Regul. Rivers: 

Res. Manag. 8(1-2):189–194.

Addition of rocks and stones to a channelized river increased brown trout 

densities, especially in areas in contact with the riverbanks. The new areas of 

rock addition provided cover for fish as well as greater variations in depth and 

flow conditions. Although there was no significant difference between the 

unmodified riverbanks with the artificial areas under the bridges, densities were 

more than twice as high along the modified river banks than under and around the 

bridges. Increased density of the young trout at the stony areas is probably the 

result of redistribution of fish in the river.

Brock, W. A. 1986. Enhancement of rearing 

habitat for juvenile steelhead trout (Salmo 

giardneri) by boulder placement in a tributary 

to the Klamath River. Thesis. Humboldt 

State Univ., Arcata, CA.

Boulder placement. The estimated age 1+ steelhead population increased 300% 

in the section where boulder clusters were not lost or transported by a large flood 

event, while the estimated population in the control reach decreased 35%. 

Biomass of steelhead age 1+ in the section with boulder clusters increased 

256%/m2 and 143%/m3. Biomass in the control reach decreased 41%/m2 and 

22%/m3

.

Brooks, A. P., P. C. Gehrke, et al. 2004. 

Experimental reintroduction of woody debris 

on the Williams River, NSW: Geomorphic 

and ecological responses. River Res. Appl. 

20(5):513–536.

Created engineered logjams. After 12 months, the major geomorphologic 

changes in the test reach included an increase in pool and riffle area and pool 

depth, the addition of a pool-riffle sequence, and increase by 0.5–1 m pool-riffle 

amplitude, a net gain of 40 m3 of sediment storage per 1,000 m2 of channel area 

(while the control reach experienced a net loss of 15 m3

/1,000 m2 over the same 

period), and a substantial increase in the spatial complexity of bed-material 

distribution. Fish assemblages in the test reach showed an increase in species 

richness and abundance, and reduced temporal variability compared to the 

reference reach. Eight species were recorded in the control reach for a total of 

545 fish, while 12 species were in the test reach for a total of 2,340 fish.

Brooks, S. S., M. A. Palmer, et al. 2002. 

Assessing stream ecosystem rehabilitation: 

Limitations of community structure data.

Restor. Ecol. 10(1):156–168.

Created “high” and “low” heterogeneity treatments in riffles by altering the 

variability of streambed particle sizes. The initial disturbance and riffle 

construction significantly reduced invertebrate abundance by 67% in both high 

and low heterogeneity riffles, but invertebrate abundance and species richness did 

not differ between treatments. Results support the idea that changes in 

community structure may be poor indicators of environmental change in highly 

variable environments inhabited by mobile, fugitive taxa.
55

Burgess, S. A., and J. R. Bider. 1980. Effects of 

stream habitat improvements on invertebrates, 

trout populations, and mink activity. J. Wildl. 

Manag. 44(4):871–880.

Habitat improvement resulted in brook trout population and biomass increases of 

208% and 179%, respectively, after 2 years. Crayfish biomass was 220% greater 

in the improved section. Mink did not respond to the trout biomass increase.

Carlson, L. D., and M. S. Quinn. 2005. 

Evaluating the effectiveness of instream 

habitat structures for overwintering stream 

salmonids: A test of underwater video.

N. Am. J. Fish. Manag. 25(1):130–137.

Videos of winter use of V-weirs by salmonids. There were no significant 

interaction effects between habitat and ice cover. There were no significant 

differences in the number of fish observed between the ice-covered and openwater pools or between treatment and control pools. There were no statistically 

significant differences in the number of fish observed at control and V-weir pools 

in the open-water sites, but there were significantly more fish observed at V-weirs 

than control sites in the ice-covered pool.
56

Cederholm, C. J., R. E. Bilby, et al. 1997. 

Response of juvenile coho salmon and 

steelhead to placement of large woody debris 

in a coastal Washington stream. N. Am. J. 

Fish. Manag. 17:947–963.

Large woody debris (LWD) addition. Amount of LWD in the engineered site 

was 8.9 times the pretreatment level, while at the logger’s choice site it was 3.6

times. The number of LWD pieces increased 2.3-fold in the reference site. 

Increased piece length and abundance resulted in an 11.5-fold increase in total 

wood volume in the engineered site and a threefold increase in the logger’s 

choice site. Proportion of pools in the engineered site increased from 33%, 38%,

and 38% in spring, fall, and winter to 59%, 74%, and 56%. Logger’s choice 

site’s pools increased from 7% to 12%. Fast-water habitats decreased at the two 

enhanced sites. Abundance of coho salmon during spring and fall showed no 

response to enhancement, but juvenile coho responded in the winter. Prior to 

enhancement, the reference site supported nearly 10 times the number of presmolt 

coho salmon as the two treatment sites. After enhancement, coho abundance 

increased twentyfold in the engineered site and sixfold in the logger’s choice site. 

There was no significant differences in age-0 steelhead abundance during spring 

among the sites prior to enhancement and no change after enhancement in the 

spring; however, age-0 steelhead abundance declined significantly in the logger’s 

choice site. The number of coho smolts migrating from the engineered and 

logger’s choice sites increased following enhancement. Prior to enhancement, an 

average of 117 smolts/year emigrated from the engineered site and 55 smolts/year 

from the logger’s choice site. After enhancement, average annual yield increased 

to 370 smolts/year from the engineered site and 142 smolts/year from logger’s 

choice. Winter population levels of juvenile coho salmon and age-0 steelhead 

were related to mean winter discharge and maximum winter discharge. Coho 

salmon populations decreased more rapidly with increasing mean winter 

discharge than did age-0 steelhead.
57

Champoux, O., P. M. Biron, et al. 2003. 

The long-term effectiveness of fish habitat 

restoration practices: Lawrence Creek, 

Wisconsin. Ann. Assoc. Am. Geogr.

93(1):42–54.

Bank-cover deflectors, large boulders, and woody debris. Fish habitat in 1999 

was better than in 1963, but has deteriorated substantially since 1966. Pool area 

increased from 267 m2 to 625 m2 between 1963 and 1966, but has decreased to 

488 m2 since then. Most of this deterioration is in the morainic section. In the 

outwash plain, the area occupied by pools has remained constant since 1966; in 

the morainic section, most structures are no longer efficient and the channel is 

unstable due to high bed-shear stress values, which entrain bed and bank erosion. 

In 1963, the mean depth was 0.12 m. After improvements, the mean depth 

increased to 0.21 m in 1966 then decreased to 0.17 in 1999. There is a clear 

difference in the frequency of the fluctuations in elevation between the morainic 

and outwash sections, which indicates a greater variability of aquatic habitat in 

the outwash section.
58

Chapman, D. W. 1996. Efficacy of structural 

manipulations of instream habitat in the 

Columbia River basin. Northwest Sci.

5(4):279–293.

Summary of many projects. Instream structures: there was no significant 

difference in preference for the treatments tested between trout and salmon. 

Under natural densities young salmon preferred the streambank treatment, while 

at higher densities (1.5 times natural) fish were displaced into the less preferred 

treatments. Hydrologic conditions are important to the success of instream 

structures. Wing deflectors did not produce the anticipated habitat features; there 

was limited increased velocity and scouring. The results that the projects had any 

direct effect on productive capacity due to structure placement would be difficult 

to verify. Nutrient additions increased benthic invertebrate abundance, which 

subsequently resulted in an increase of salmonid biomass. Barrier removal: 

activities after removal did not show any increase in salmonid biomass in the 

upper stations. Biomass remained low and the length frequency distributions of

fish in the two areas were dissimilar. Spawning gravel additions: the number and 

proportion of fry increased in all stations. Newly placed gravel was selected for 

and used by spawning salmon. One site had four redds in 1995 and 23 in 1996 

and had the highest success of gravel retention, greater than 90% as compared to 

approximately 50% in other sites. Major restoration/rewatering: average

salmonid biomass was always higher in the affected section than that observed in 

the control site and the majority of biomass in both areas was derived from brook 

trout 1+ and older. The difference between the average biomass observed in the 

new habitat compared to the control sites increased 1.8 times in 1991, 2.1 times in 

1993, and 3.6 times in 1999. Pools with lunkers had on average 2.6 times the 

biomass of large brook trout than those without lunkers. The average fish 

biomass and available habitat in 1992, years after restoration, indicated a 

potential production of 51.46 kg, a 2.9-fold increase. The estimate for potential 

production in 1996 was 263.94 kg, a 14.7-fold increase from prerestoration 

levels. The site had a habitat gain of 215 units (30% increase) and increase in 

potential production of 246 kg from 1990 to 1996.
59

Clarke, K., and D. Scruton. 2002. Evaluating 

efforts to increase salmonid productive 

capacity through habitat enhancement in the 

low diversity/production systems of 

Newfoundland, Canada. In Proceedings of the 

13th International Salmonid Habitat 

Enhancement Workshop, Hotel Westport,

Mayo, Ireland, 16–19 September 2002, 

p. 160–182. Central Fisheries Board, Dublin, 

Ireland.

Summarized several habitat improvement projects evaluated in Newfoundland. 

(Noel Paul’s Brook and Joe Farrell Brook instream structures, Great Gull River 

barrier removal, Placentia River gravel placement, Cole Pond nutrient addition, 

Seal Cover River, Pamehac Brook rewatering/reconnection). Most projects were 

successful in meeting objectives, but results varied by project (see publication for 

details).

Coe, H, J., P. M. Kiffney, et al. 2006. A 

comparison of methods to evaluate the 

response of periphyton and invertebrates to 

wood placement in large Pacific coastal rivers. 

Northwest Sci. 80(4):298–307.

See Coe et al. 2009 below.

Coe, H., P. M. Kiffney, et al. 2009. Periphyton 

and invertebrate response to wood placement 

in large Pacific coastal rivers. River Res. 

Appl. 25(8):1025–1035.

No fish. Periphyton and invertebrates. Among years and rivers, periphyton 

biomass and invertebrate densities were significantly higher on engineered 

logjams than on cobbles within the same reach. Adding wood to reaches with 

little or no naturally occurring wood increased overall habitat surface area and the 

potential of increased productivity relative to reaches with low levels of wood. 

Among years, mean ash-free dry mass, chlorophyll a concentration, and 

autotrophic index were as much as 1.5, six, and four times higher, respectively, 

on wood than on cobble in the Elwha River. In the Stillaguamish River, mean 

ash-free dry mass, chlorophyll a concentration, and autotrophic index were three, 

eight, and five times higher, respectively, on wood.
60

Crispell, J. K., and T. A. Endreny. 2009. 

Hyporheic exchange flow around constructed 

in-channel structures and implications for 

restoration design. Hydrol. Process.

23(8):1158–1168.

No fish, no good numbers. Study of constructed in-channel structure controls on 

hyporheic exchange flow was conducted using stream and hyporheic temperature

amplitude analysis and computational fluid dynamics (CFD) hydraulic 

simulations. Results indicate a pattern consistent with natural riffle pool 

sequences and analysis agreed with the direction of flow simulated with CFD at 

80% of the locations. CFD simulation demonstrated that increasing streamflows 

result in changes in hyporheic exchange flow spatial patterns and magnitude at 

each structure.

Crispin, V., R. House, et al. 1993. Changes in 

instream habitat, large woody debris, and 

salmon habitat after the restructuring of a 

coastal Oregon stream. N. Am. J. Fish. 

Manag. 43:96–102.

Large woody debris. Restructuring caused substantial changes favoring suitable 

habitat for coho salmon; meanwhile, the untreated reach became less favorable 

for rearing coho. Stream surface area and water volume, respectively, increased 

74% and 168% in the treated reach, and 8% and 37% in the untreated reach. 

Surface area of pool and suitable off-channel habitat increased nearly fivefold in 

the treated reach at summer low flow. In the treated reach, newly recruited large 

woody debris was 52% greater in mean length and 60% greater in mean diameter 

than in the untreated reach. In the treated reach, suitable summer habitat for 

coho increased fivefold and suitable winter habitat increased sixfold; in the 

untreated reach suitable summer habitat decreased by half and no winter habitat 

was available.

D’Aoust, S. G., and R. G. Millar. 2000. 

Stability of ballasted woody debris habitat 

structures. J. Hydraul. Eng. 126(11):810–817.

Stability of placed large woody debris (LWD) structures. The stability of single 

LWD and single LWD with root wad structures can be successfully predicted by 

theory. The stability of the multiple LWD structures proved to be more complex

to predict.

Dauwalter, D. C., R. G. Hyler, et al. 2004. 

Responses of fish populations to the 

installation of rock vanes in Spring Creek, 

Oklahoma. In J. R. Copeland, F. Fiss, et al. 

(eds.), Warm-water Streams Symposium II,

p. 49–52. Southern Division American 

Fisheries Society, Oklahoma City, OK.

Rock vanes. Installation changed stream habitat. Substrate distributions did not 

change at the control site among dates, but included bedrock, boulders, and more 

silts at the project site. Abundance of submergent vegetation increased more at 

the project site. Water depth and velocity heterogeneity among transects did not 

change. Relative weights of smallmouth bass and shadow bass decreased after 

rock vane installation. Fish assemblage stability did not differ between sites. 

Shadow bass abundance appeared to respond negatively at first to the project, but 

then showed an increase, whereas abundance in the control site decreased. 

Smallmouth bass abundance did not appear to change at the project site.
61

DeVries, P., K. L. Fetherston, et al. 2012. 

Emulating riverine landscape controls of 

beaver in stream restoration. Fisheries 

37(6):246–255.

No fish. Constructed log flow-choke structures that mimic the hydraulic function 

of a natural beaver dam during flooding. Monitoring showed that within 1–2 

years, beaver built more persistent dams in close proximity to installed structures. 

Increased hydraulic connectivity with the floodplain was observed.

Dewberry, C., P. Burns, et al. 1998. After the 

flood. The effects of the storms of 1996 on a 

creek restoration project in Oregon. Restor. 

Manag. Notes 16(2):174–182.

Flood effects on salmonid production varied among species and depended on the 

life history stage of the species. Steelhead and cutthroat trout more than 1 year 

old appeared to be the least affected by the floods and their smolt numbers were 

higher after the flood than before. Chinook salmon outmigrants dropped from 

247,000 in 1995 to 50,000 in 1996.

Ebrahimnezhad, M., and D. M. Harper. 1997. 

The biological effectiveness of artificial riffles 

in river rehabilitation. Aquat. Conserv.: Mar. 

Freshw. Ecosyst. 7(3):187–197.

Artificial riffles. Mean diversity of invertebrates in the natural riffle and two 

shallower artificial riffles were highest, while those of the other deeper, artificial 

riffle and the channelized runs were lowest. There was a significant negative 

correlation between diversity and depth, and a significant positive correlation 

between diversity and velocity. Hydropsychidae, Simuliidae, Baetidae, Elmidae,

and Hydracarina were the abundant taxa of artificial riffles (all are typical of 

faster flowing riffles) and Chironomidae were slightly more abundant in run sites 

(64.7%) than the artificial riffle sites (59.2%). There were small differences 

between the natural riffle site and the artificial riffle sites: a greater relative 

abundance of Hydropsychidae and Tubificidae in the latter (9.3%, 5.9%) 

compared with the natural site (38%, 0.7%), and greater relative abundance of 

Hydracarina, Baetidae, and Elmidae in the natural site (7.3%, 5.7%, 4.2%) than in 

the artificial ones (2.4%, 3.1%, 2.9%).

Ehlers, R. 1956. An evaluation of stream 

improvement project devices constructed 18

years ago. Calif. Fish Game 42:203–217.

Large woody debris and rock dams. No numbers. Of the 67 pools developed by 

the 41 dams and deflectors built in 1935, only 15 remained in 1953. Log dams 

are superior and generally more durable than rock dams on streams of slight 

gradient. Pools formed below the structures are more permanent than pools 

above.
62

Ernst, A. G., B. P. Baldigo, et al. 2010. Effects 

of natural-channel-design restoration on 

habitat quality in Catskill Mountain streams, 

New York. Trans. Am. Fish. Soc.

139(2):468–482.

Rainbow, brook, and brown trout. On average, stream stability increased at 

treatment sites for 2–5 years after restoration. Mean channel depth, thalweg 

depth, and the pool:riffle ratio generally increased, whereas mean channel width, 

percent streambank coverage by trees, and shade decreased. Habitat suitability 

indices for salmonids increased at four of six reaches after restoration.

Filoso, S., and M. A. Palmer. 2011. Assessing 

stream restoration effectiveness at reducing 

nitrogen export to downstream waters. Ecol. 

Appl. 21(6):1989–2006.

No fish. Evaluation of whether stream restoration to improve water quality is 

effective at reducing the export of nitrogen (N) in streamflow to downstream 

waters. During low discharge, lowland streams that receive minor N inputs from 

groundwater or bank seepage reduced instream N fluxes. Lowland streams with 

the highest N concentrations and lowest discharge were the most effective. 

During high flow, only those restoration projects that converted lowland streams 

to stream-wetland complexes seemed effective at reducing N fluxes. The 

observed N-removal rates were relatively high for stream ecosystems and on the 

order of 5% of the inputs to the watershed.

Floyd, T. A., C. MacInnis, et al. 2009. Effects 

of artificial woody structures on Atlantic 

salmon habitat and populations in a Nova 

Scotia stream. River Res. Appl. 25(3):272–

282.

Atlantic salmon. Large woody debris structures were effective in creating 

complex habitat. Structures narrowed the channel, scoured pools, and undercut 

banks. They created habitat that parr used for refuge and spawners used for cover 

and resting. Gravel accumulated. Treatment reaches had higher spawning 

densities than those without them.

Frimpong, E. A., J. G. Lee, et al. 2006. Costeffectiveness of vegetative filter strips and 

instream half-logs for ecological restoration.

J. Am. Water Resour. Assoc. 42(5):1349–

1361.

Logs/large woody debris. Cost-effectiveness ratios for vegetative filter strips 

decreased from $387 to $277 per 100 m for a 1% increase in Index of Biological 

Integrity scores from first- to fifth-order streams with 3% discount and 30-year 

recovery. This cost weighted by proportion of stream orders was $360. The ratio 

decreased with decreasing time of recovery and discount rate. Based on 

installation costs and an assumption of equal recovery rates, half-logs were twothirds to half as cost-effective as vegetative filter strips.
63

Frissell, C. A., and R. K. Nawa. 1992. 

Incidence and causes of physical failure of

artificial habitat structures in streams of 

western Oregon and Washington. N. Am. J. 

Fish. Manag. 12:182–187.

Large woody debris fish habitat structures. The incidence of functional 

impairment and outright failure varied widely among streams; the median failure 

rate was 18.5% and the median damage rate (impairment plus failure) was 60%. 

Modes of failure were diverse and bore no simple relationship to structure design. 

Damage was frequent in low-gradient stream segments and widespread in streams 

with signs of recent watershed disturbance, high sediment loads, and unstable 

channels. Rates of damage were higher in larger and wider streams. Projects in 

streams with active channel widths wider than 15 m had a median damage rate of 

79%, while those narrower were highly variable and had a median damage rate of 

50%. High gradient streams had higher failure rates than those in gently sloping 

streams.

Fuller, D. D., and A. J. Lind. 1992. 

Implications of fish habitat improvement 

structures for other stream vertebrates. 

In Proceedings of the Symposium on 

Biodiversity of Northwestern California, 

October 28–30, 1991, Santa Rosa, CA,

p. 96–104. Wildland Resources Center, 

Division of Agriculture and Natural 

Resources, Univ. California, Berkeley.

Boulder deflectors. Steelhead utilization of instream structures was found to vary 

depending on season and streamflow. Thirteen fish were counted in the study 

reach before placement and 14 fish were counted after. Eight fish were counted 

in the control reach before placement and 10 fish were counted after. Foothill 

yellow-legged frogs utilized the 30 m reach for breeding during the 3 years prior 

to deflector placement, but not during the 3 years after. The diet of the western 

aquatic garter snake appeared to differ after placement.
64

Gard, R. 1961. Creation of trout habitat by 

constructing small dams. J. Wildl. Manag.

52(4):384–390.

Dams of rock and wood. Greatly reduced current resulted in ponds with an 

average deposition of 3.3′′ of silt, organic material, and gravel after 1 year and 

4.8′′ after 3 years. Holes were created by the digging action of the water passing 

over the dams. An average water depth of 4.5′′ increased to 17.2′′ after damming,

but fell to 5.8′′ by 1960. During the three summers following dam installation, 

the numbers of introduced brook trout were counted. Forty-nine trout were 

collected the second summer, yielding a 1-year survival rate of 38%. Seventythree percent of the fish surviving to the second summer were collected the third

summer and 39% of those surviving to the third summer lived to the fourth. The 

introduced trout spawned successfully. Average weights of bottom organisms per 

unit area at the pond sites in 1958 and 1959 were five and eight times heavier 

than the average weight per unit area at the same site before ponding. Average

number of grams per square foot of summer standing crops of bottom organisms 

was 0.67 before dams, 5.12 after 1 year, and 3.48 after 2 years.

Gard, R. 1972. Persistence of headwater check 

dams in a trout stream. J. Wildl. Manag.

36:1363–1367.

Headwater check dams. After 12 years, about half of the dams were in good to 

excellent condition. Log dams held up better than rock dams for the first 3 years,

but rock dams were generally in better condition after 12 years. Average depth of 

the ponds decreased from 16′′ to 10′′, but holes 9–13′′ deep were created below 

the dams. The standing crop of trout of catchable sizes (≥100 mm) was estimated 

to be 93 trout weighing 9.6 lb (= 394 trout per acre weighing 41 lb). Cost of 

dams and trout introduction was $154, or $12.80 per year over the 12 years.

Gargan, P., M. O’Grady, et al. 2002. The 

effectiveness of habitat enhancement on 

salmon and trout stocks in streams in the 

Corrib Catchment. In Proceedings of the 13th 

International Salmonid Habitat Enhancement 

Workshop, Hotel Westport, Mayo, Ireland, 

16–19 September 2002, p. 220–223. Central 

Fisheries Board, Dublin, Ireland.

Examined response of juvenile salmon and trout to variety of instream treatments 

(revetments, weirs, rubble mats, lateral scour pools, etc.) at paired treatment and 

control sites in 13 tributaries before and after treatment. Significantly high levels 

of Atlantic salmon parr (0.19 vs. 0.06 fish/m) and brown trout parr (0.127 fish/m 

difference), but no differences for salmon fry or brown trout fry in Lough Corrib 

catchment. Similar results were found for brown trout in the five sites in Lough 

Carra-Lough Mask catchment streams (0.32 vs. 0.07 fish/m) (salmon are not 

present in these watersheds).
65

Gerhard, M., and M. Reich. 2000. Restoration 

of streams with large wood: Effects of 

accumulated and built-in wood on channel 

morphology, habitat diversity, and aquatic 

fauna. Int. Rev. Hydrobiol. 85(1):123–137.

Large woody debris. The addition of wood improved the channel morphology 

within 4 years. The variation in channel width and depth was considerably larger 

than in a regulated section. The extension of the riparian zone, especially of the 

semiaquatic gravel and sand bars, was strongly correlated with the amount of 

large wood that accumulated in a single section. The number of microhabitats 

and their patchiness on the stream bottom was higher in restored sections, as well 

as the density of invertebrates and the number of species. The number of discrete 

microhabitat patches increased from 7 to 14 patches/m stream course in the 

restored sections, compared to 4 patches/m in the regulated section.

Giannico, G. R., and S. G. Hinch. 2003. The 

effect of wood and temperature on juvenile 

coho salmon winter movement, growth, 

density, and survival in side channels. River 

Res. Appl. 19(3):219–231.

Wood addition increased juvenile coho salmon winter carrying capacity and 

spring smolt output only in the “colder” surface-fed side channel. In contrast, in 

the groundwater-fed side channel, with relatively higher water temperatures, the 

wood treatment slightly reduced the channel’s carrying capacity and the spring 

output of coho smolts. In the warmer groundwater-fed area, the control and 

wood-treated halves showed similar declines in fish densities, whereas in the 

colder surface-fed area, the decrease in densities was 50–60% greater in the 

control half than in the wood-treated half between January and May. Although 

the values of the relative index of survival for juvenile coho salmon varied widely 

between both side channels and from year to year, they were consistently higher 

in the wood-treated side. For each year, juvenile coho growth rates between fall 

and spring were consistently higher in the wood-treated halves of the side 

channels.

Gidley, C. A., D. L. Scarnecchia, et al. 2012. 

Fish community structure associated with 

stabilized and unstabilized shoreline habitats, 

Coeur d’Alene River, Idaho, USA. River Res. 

Appl. 28(5):554–566.

Bank stabilization. Seventeen species. Fish relative abundance was significantly 

higher at stabilized sites. There was a possible correlation between relative 

abundance and diameter of rock at stabilized sites. Brown bullhead, northern 

pike, and pumpkinseed were captured more readily at stabilized shoreline sites. 

Stabilized structures provide stable habitat year-round. Overall, stabilized 

shorelines were not found to be adversely affecting fish relative abundance, 

diversity, and species composition under the existing low fraction (2.5%) of bank 

stabilization.
66

Gore, J. A., D. J. Crawford, et al. 1998. An 

analysis of artificial riffles and enhancement 

of benthic community diversity by physical 

habitat simulation (PHABSIM) and direct 

observation. Regul. Rivers: Res. Manag.

14(1):69–77.

Artificial riffles. The simulation predicted that this reach contained significantly 

higher amounts of available benthic habitat at low flows (more than tripled), and 

over 40% of the total wetted area should support high benthic community 

diversity at optimal flows. The presence of artificial riffles contributed most of 

this habitat enhancement. A plot of cell-by-cell composite habitat and suitability 

and sample diversity from these cells revealed a significant correlation between 

PHABSIM predictions and actual community diversity.

Gore, J. A., and S. W. Hamilton. 1996.

Comparison of flow-related habitat 

evaluations downstream of low-head weirs on 

small and large fluvial ecosystems. Regul. 

Rivers: Res. Manag. 12(4–5):459–469.

Wood weirs. Simulation using PHABSIM (physical habitat simulation) 

demonstrated that benthic invertebrate habitat can be dramatically increased at 

low flows (up to five times higher) after placement of structures that improve 

hydraulic conditions to sustain maximum diversity of the benthic community. 

These low-head structures augment habitat under high flow conditions.

Gortz, P. 1998. Effects of stream restoration on 

the macroinvertebrate community in the River 

Esrom, Denmark. Aquat. Conserv.: Mar. 

Freshw. Ecosyst. 8(1):115–130.

Restoration using gravel, boulders, and stream concentrators. Results were a 

deeper and narrower stream with a higher flow velocity near the bottom and a 

coarser substrate compared with the reference section. The fauna showed higher 

similarity to the fauna found on the stony bottom sections due to immigration of 

taxa preferring stony substrate. Saprobic index and Danish fauna index generally 

improved from II to/toward I-II. Clean-water species such as Agapetus ochripes

and Limnius volckmari were found in significantly higher numbers in the restored 

sections compared with the reference section. Five times as many trout spawning 

redds occurred in the restored sections as in the nonrestored. However, 

electrofishing revealed few young-of-the-year trout and did not reflect spawning 

success.

Gowan, C., and K. D. Fausch. 1996a. Longterm demographic responses of trout 

populations to habitat manipulations in six 

Colorado streams. Ecol. Appl. 6:931–946.

Log weirs. Mean depth, pool volume, total cover, and the proportion of the fine 

substrate particles in the streambed increased in treatment sections within 1 to 2 

years, whereas habitat in adjacent controls remained unchanged. Abundance and 

biomass of adult fish, but not juveniles, increased in treatments relative to 

controls in all streams. Recaptures of trout that were tagged and others that were 

batch marked revealed that immigration was primarily responsible for increased 

adult abundance and biomass, whereas no biologically significant differences 

occurred for recruitment, survival, or growth. Trout biomass increased in 

treatment sections because fish immigrated, not because growth rates increased.
67

Gowan, C., and K. D. Fausch. 1996b. Mobile 

brook trout in two high-elevation Colorado 

streams: re-evaluating the concept of restricted 

movement. Can. J. Fish. Aquat. Sci. 53:1370–

1381.

Wood weirs. Brook trout movement was most common in the upstream direction 

during summer, and about equal upstream and downstream between summers. 

Highest rates of movement occurred during and just after runoff, and before 

spawning, but substantial numbers of fish moved throughout the summer. Fish 

captured moving through weirs tended to be longer but in poorer condition than 

fish captured during electrofishing between weirs. On the basis of capture 

histories for individual fish, 59% and 66% in the two streams moved at least 50 m 

(up to 3,380 m), even though most could be tracked only for several months. 

Long-range movements were relatively common, which is contrary to most 

literature on resident stream salmonids.

Haapala, A., T. Muotka, et al. 2003. 

Distribution of benthic macroinvertebrates and 

leaf litter in relation to streambed retentivity: 

Implications for headwater stream restoration.

Boreal Environ. Res. 8(1):19–30.

Boulders and leaf retention. Streambed complexity increased, stream channel 

widened, water velocity lowered, and moss cover decreased. Leaf retention was 

25% before restoration and 75% after. Leaf biomass was 28 times higher in 

retention than in random sites. Densities in retention sites were roughly twice as 

high as in random sites, both before and after restoration.

Hale, J. G. 1969. An evaluation of trout stream 

habitat improvement in a north shore tributary 

of Lake Superior. Minn. Fish. Investig. 5:37–

50.

Artificial deflectors and shelters. Average depth of cross-sectional profiles 

increased 1.74′′. Greatest physical change was change in composition of bottom 

soil type from 26% silt and 14% gravel before to 17% silt and 24% gravel after. 

Fifty-seven log shelters increased surface cover by 3.8% of total surface area. 

Abundance of young-of-the-year brook trout increased 894% and older trout 

223%. Total standing crop of brook trout increased 356% while in the reference

area the increase was only 65%. Anglers increased by 219 vs. 46 in the reference

area. After alteration there was a 362% increase in average annual harvest vs. 

51% in reference area. Catch rate of native brook trout rose from 0.58 before to 

0.89 after, while reference sector dropped from 0.82 to 0.75 fish per man hour. 

Average annual harvest of native brook trout increased by 807 fish at an annual 

cost of $745 vs. $968 for annual cost of providing the same number of hatchery 

brook trout.
68

Hamilton, J. B. 1989. Response of juvenile 

steelhead to instream deflectors in a high 

gradient stream. In R. E. Gresswell, B. A. 

Barton, et al. (eds.), Practical approaches to 

riparian resource management, p. 149–158. 

U.S. Bureau of Land Management, Billings, 

MT.

Deflectors in a high gradient stream. After winter flows only 14% of structures 

were intact. Changes in steelhead fry and parr numbers, densities, biomass, and 

standing crop in treated sections were not significantly different from changes in

control sections. Condition of parr was significantly reduced in treated sections 

after winter flows. A significantly lower percentage of marked parr remained in 

the treatment sections after alteration. A review of other studies showed that 

habitat improvement projects that increase populations have usually been on 

lower gradient (mean = 1%) reaches.

Harper, D., M. Ebrahimnezhad, et al. 1998. 

Artificial riffles in river rehabilitation: Setting 

the goals and measuring the successes. Aquat. 

Conserv.: Mar. Freshw. Ecosyst. 8:5–16.

Artificial riffles. Twenty of 26 riffles retained their original physical character 

while six were deep, slow flowing, and covered with sand or silt. Shallow riffles 

retained their coarse particle dominance and caused the scouring between 

themselves of deeper pools than were found elsewhere in the stretch. Shallow 

riffles had high flow velocities that resulted in richness of functional habitats not 

found elsewhere. Invertebrate colonization showed a clear distinction between 

communities of shallow, fast-flowing riffles and deeper, slow-flowing runs and 

silted riffles. Riffle reinstatement in lowland rivers of low energy will produce 

desirable geomorphological and ecological changes if the riffles are spaced 

according to geomorphological “first principles” and are shallow (<30 cm depth) 

under low-flow conditions.

Harper, D. J., and J. T. Quigley. 2005. No net 

loss of fish habitat: A review and analysis of 

habitat compensation in Canada. Environ. 

Manag. 36(3):343–355.

Development activities that resulted in the greatest percent of HADDs (harmful 

alteration, disruption, and destruction of fish habitat) included urban 

development, roads and highways, and forestry (33%, 20%, and 18%,

respectively). Not assessing particular projects.
69

Harrison, S. S. C., J. L. Pretty, et al. 2004. The 

effect of instream rehabilitation structures on 

macroinvertebrates in lowland rivers. J. Appl. 

Ecol. 41(6):1140–1154.

Artificial riffles and flow deflectors. Artificial riffle benthos had a faster current, 

a coarser substratum, and was shallower than reference area. Depth and 

substratum particle size differed little between flow deflector and reference area, 

although velocity downstream of the deflector tip was great and velocity in the 

lee of the deflector lower than reference area. At a habitat scale, the benthos of 

artificial riffles, but not flow deflectors, had higher abundance, taxon richness,

and diversity than reference area. The impact of artificial riffles was most 

marked for benthic rheophilic taxa. Invertebrate diversity was highest in 

marginal macrophytes and abundance highest in instream macrophytes. Neither 

artificial riffles nor flow deflectors had any significant impact on the taxon 

richness of the benthos or of the rehabilitated stretch of the river as a whole. 

Local rehabilitation structures appeared to have minor biological effects in 

lowland rivers.

Hartzler, J. R. 1983. The effects of half-log 

covers on angler harvest and standing crop of 

brown trout in McMichaels Creek, 

Pennsylvania. N. Am. J. Fish. Manag. 3:228–

238.

Installed half-log covers. Anglers caught 10% more trout in treated sections and 

brown trout harvest declined 11% in untreated sections. Number and weight of 

larger trout collected by electrofishing rose by 12% and 14% respectively, but 

those increases were not statistically significant. Response of “catchable size”

brown trout to cover enhancement was poor.

Hester, E. T., M. W. Doyle, et al. 2009. The 

influence of instream structures on summer 

water temperatures via induced hyporheic 

exchange. Limnol. Oceanogr. 54(1):355–367.

No fish. Varied the height of an experimental weir and monitored the hydraulic 

and thermal response of surface and subsurface water. The presence of the 

structure altered stream temperature patterns, increasing thermal heterogeneity in 

surface water and shallow sediments by up to 1°C. Streambed hydraulic 

conductivity appears to be the overriding factor determining the magnitude of 

weir-induced hyporheic influence on surface and subsurface water temperatures.
70

Hilderbrand, R. H., A. D. Lemly, et al. 1997. 

Effects of large woody debris placement 

on stream channels and benthic 

macroinvertebrates. Can. J. Fish. Aquat. 

Sci. 54(4):931–939.

Large woody debris (LWD) addition. Pool area increased 146% in the systematic 

placement and 32% in the random placement sections of the low-gradient stream. 

High-gradient stream changed very little after LWD addition. Logs oriented as 

dams were responsible for all pools created, regardless of method of placement. 

Multiple log additions created only two pools while the other seven were created 

by single LWD pieces. Debris-formed pools increased from six to 14 (61%) 1 

year after additions. Total invertebrate abundance did not change as a result of 

LWD additions in either stream, but net abundances of Plecoptera, Coleoptera, 

Trichoptera, and Oligochaeta decreased, while Ephemeroptera increased 

significantly with the proportional increase in pool area in the low-gradient 

stream.

Hilderbrand, R. H., A. D. Lemly, et al. 1998. 

Design considerations for large woody debris 

placement in stream enhancement projects.

N. Am. J. Fish. Manag. 18(1):161–167.

Log length exerted a critical influence in stabilizing large woody debris (LWD)

pieces. Logs longer than the average bankfull channel width (5.5 m) were 

significantly less likely to be displaced than logs shorter than this width. The 

longest log in stable log groups was significantly longer than the longest log in 

unstable groups. Longer logs moved less often, but they moved farther when 

entrained in the current than the majority of mobile smaller logs. Log stability 

did not differ between a treatment section with randomized placement of LWD 

and a section in which LWD was placed systematically. Channel scouring 

typically occurred around LWD oriented as ramps and as dams perpendicular to 

streamflow; aggradation occurred above and below pieces oriented as dams 

angled to the current. Microscale channel responses to LWD additions varied.

House, R. 1984. Evaluation of improvement 

techniques for salmonid spawning. In T. J. 

Hassler (ed.), Proceedings: Pacific Northwest 

Stream Habitat Management Workshop, p. 5–

13. Humboldt State Univ., Arcata, CA.

Chinook salmon, pink salmon, chum salmon, coho salmon, and steelhead. 

Gabions increased the usable spawning area, trapping an average of 15.9 m2 in 

one creek and 8.3 m2 in another creek of high quality gravels at each structure. 

Most treated areas showed a disproportionately high use by spawning salmonids 

compared to untreated areas.
71

House, R. 1996. An evaluation of stream 

restoration structures in a coastal Oregon 

stream 1981–1993. N. Am. J. Fish. Manag. 

16:272–281.

Treated with mostly full-spanning, rock-filled gabions in 1981 and boulder 

structures in 1987. Freshets in the winter of 1981–1982 filled all gabion 

structures with large gravel; the surface area of pool and low-gradient riffle 

habitats increased, but area of high-gradient riffle habitat decreased. From 1985 

through 1993, the average number of coho salmon spawners increased 2.5 times

compared with returns during 1981–1984. Treated areas supported significantly 

more juvenile coho salmon and cutthroat trout and had higher overall salmonid 

biomass than control areas, whereas age-0 trout (cutthroat trout plus steelhead) 

and juvenile steelhead showed no increases. For the entire 1.7-km reach 

receiving treatment, the number of coho salmon juveniles was higher after than 

before treatment, whereas numbers of steelhead and cutthroat trout fry and 

juveniles remained constant. After structures were installed, peak returns of adult 

coho increased sixfold from the 1980–1984 average and the percentage of wild 

spawners increased from 36% before to 84% after construction. Coho juveniles 

increased from an average of 3,754 fish during 1981–1983 to an average of 9,458 

fish during 1984–1989. Between 1981 and 1992, more than 50% of the coho 

salmon and steelhead spawned on newly deposited, higher quality gravels 

associated with 15 gabion structures that fully spanned the bankfull channel 

width. Quality of gravels impounded by gabions equaled or exceeded the quality 

of gravels in unmodified areas of the creek. Habitats, primarily pools created by 

gabion structures, lasted 10 years; however, disintegration of wire mesh tops 

starting in 1989 caused a slow reduction in pool habitat and gravel riffles at 

treated sites.
72

House, R. A., and P. L. Boehne. 1985. 

Evaluation of instream enhancement 

structures for salmonid spawning and rearing 

in a coastal Oregon stream. N. Am. J. Fish. 

Manag. 5:283–295.

Stream enhancement structures installed were successful and functional after two 

winters with usual freshets. The structures dramatically increased the diversity of 

the streambed, trapped gravel, and created shallow gravel bars and deep, covered 

pools. Also the number, size, and quality of the pools increased in areas with 

structures. Water volume increased 84.8 m3 and surface area increased 187 m2

after installation. Maximum depth increased by 22 cm in 1982 and 35 cm in 1983 

on treated sites, whereas control sites showed no increase in 1982 and an increase 

of only 9 cm in 1983. The pool/riffle ration changed from 1:3 before treatment to 

4:1 after treatment. Pool habitat in treated sites increased by 53% while pool 

habitat in control areas increased by 22%. Coho salmon and steelhead spawning 

increased substantially, as well as the numbers of rearing coho, steelhead fry, and

steelhead and cutthroat trout parr. Coho fry densities in 1982 were 422% and 

541% greater, respectively, in sites with two gabions than in those with one 

gabion.

House, R. A., and P. L. Boehne. 1986. Effects 

of instream structures on salmonid habitat and 

populations in Tobe Creek, Oregon. N. Am. J. 

Fish. Manag. 6:38–46.

Large woody debris caused the development of secondary channels, meanders, 

pools, and undercut banks in an unlogged, mature-conifer, stream section. These 

were absent in the young-alder section. The mature-conifer section had more 

than twice as many pools and 10 times the amount of spawning gravel. Prior to 

enhancement, three times as many coho salmon and trout fry were living in the 

mature-conifer stream section. Available water in pools was 126% greater in the 

stream section above the culvert. At treated sites, the gravel substrate increased 

by 233% and usable spawning gravel area increased 25-fold. The section above 

the culvert was supporting 12 times as many coho as below the culvert. Trout 

were about three times more abundant above the culvert than below. There was a 

positive correlation between coho numbers and the presence of large woody 

debris. Structure is most likely a more important factor than shade in a stream’s 

capacity for producing salmonids.
73

House, R., V. Crispin, et al. 1989. Evaluation of 

stream rehabilitation projects—Salem District 

(1981–1988). U.S. Dept. Interior, Bureau of 

Land Management, Portland, OR.

Case studies. Narrow riffle areas were converted into long, wide pool habitat. 

Work more than doubled the surface area, with the low flow-wetted perimeter 

increasing an average of 22 square feet for each 3 feet of treated stream. The 

potential increase in populations was an estimated 92,140 juvenile coho salmon, 

14,170 trout fry, 6,780 yearling steelhead, and 2,560 sea-run and resident yearling 

cutthroat trout. Generally the greatest increase occurred in channels more than 39 

feet wide and treated with many full-spanning wood structures. Structures also 

substantially increased spawning areas and use by adult spawners in treated 

reaches. Long-term monitoring on one project has shown a fourfold increase in 

juvenile coho and a thirteenfold increase in adult coho, with an average annual 

ocean catch of 181 fish attributed to the project. Stream rehabilitation work 

seems to have achieved structural, habitat, biological, and economic success. 

The best and probably least costly method of rehabilitating streams in through a 

riparian management policy that provides optimum numbers of all sizes of 

conifers along all streams used by salmonids. Recommendations are to install 

large, full-spanning structures made of natural material in large tributaries and 

upper mainstem rivers, manage riparian zones to produce optimum numbers of 

mature conifers, continue rehabilitation work in key reaches of coastal streams,

and continue long-term evaluations to determine accurate project benefits.

Hunt, R. L. 1969. Effects of habitat alteration 

on production, standing crops, and yield of 

brook trout in Lawrence Creek, Wisconsin. 

In T. G. Northcote (ed.), Symposium on 

Salmon and Trout in Streams, H. R. 

Macmillan lectures in fisheries, p. 281–312. 

Univ. British Columbia, Vancouver, BC.

Bank covers and current deflectors reduced surface area by 50%, increased 

average depth by 60%, increased pools by 52%, and increased permanent 

overhanging bank cover for trout by 416%. Sand substrate was reduced by 40%, 

silty bottom was reduced by 70%, but gravel area was increased by 11%. 

Average number of legal-sized trout (8′′ plus) increased by 156%, annual 

production increased by 17%, and mean standing crop of trout increased by 40%. 

Age 1+ trout accounted for 78% of average standing crop before alteration, but 

87% after. Yield increased by 196% and food consumption increased by 28%.
74

Hunt, R. L. 1976. A long-term evaluation of 

trout habitat development and its relation to 

improving management-related research.

Trans. Am. Fish. Soc. 105:361–364.

Large woody debris. Mean annual biomass of trout, mean annual number of trout 

over 15 cm, and annual production increased significantly during the 3 years

following development, but even more so during the second 3 years. Maximum

number and biomass and number of legal trout did not occur until 5 years after 

completion of the development. Peak number of brook trout more than 20 cm 

was reached the sixth year postdevelopment.

Hunt, R. L. 1988. A compendium of 45 trout 

stream habitat development evaluations in 

Wisconsin during 1953–1985. Wisconsin 

Dept. Natural Resources, Madison.

Forty-five case studies. Success was judged on the basis of percentage changes 

within treatment zones for each of six possible variables standardized to “per 

mile:” total number of trout, number of 6′′ or larger (legal size), number of 10′′ or 

larger (quality size), total biomass, angler hours, and angler harvest. Level 1 

success = postdevelopment variable increases of 25% or more, Level 2 = 

increases of 50% or more. Approximately 60% of the quantified changes in the 

six standard variables exceeded success Level 1 after habitat development; 43% 

exceeded success Level 2. At least one trout population variable improved after 

development in 93% of wild trout in 41 treatment zones containing wild trout. 

Approximately 72% of the 185 measurements of change among the four

standardized population variables in these zones were positive, 26% were 

negative, and 2% showed no average change. Average empirical 

postdevelopment changes for the population’s wild trout in 41 treatment zones 

included a 21% increase in number of trout (to 1,940/mile), a 35% increase in 

legal-sized trout (to 828/mile), a 56% increase in quality-size trout (to 156/mile),

and a 49% increase in biomass (to 242 lb/mile).

Huusko, A., and T. Yrjänä. 1995. Evaluating 

habitat restoration of rivers channelized for 

log transport: A case study of the River 

Kutinjoki, northern Finland. Bulletin Français 

de la Pêche et de la Pisciculture 337–339:407–

413.

Boulder dams increased the diversity and patchiness of available depths, 

velocities, and dominant substrate size classes, making the rapids spatially more 

complex. The restoration procedure seems to favor 1+ or older trout. The 

restoration increased the river width from 22% to 53%.
75

Huusko, A., and T. Yrjänä. 1997. Effects of 

instream enhancement structures on brown 

trout, Salmo trutta L., habitat availability in a 

channelized boreal river: a PHABSIM 

approach. Fish. Manag. Ecol. 4:453–466.

Boulder structures. Results showed that the availability of potential physical trout 

habitat can be increased at simulated low and moderate flow conditions by 

reconstruction of the riverbed and placing instream boulder structures. The 

resulting diversity of depth and velocity conditions created a spatially more 

complex microhabitat structure. Water depth and velocity median values 

decreased owing to the enhancement at all study sites and at all simulated 

discharges, but the highest depths and velocities were almost always found 

among the postrehabilitation areas. Improved habitat conditions were able to 

sustain a larger trout population.

Hvidsten, N. A., and B. O. Johnsen. 1992. 

River bed construction: Impact and habitat 

restoration for juvenile Atlantic salmon, 

Salmo salar L., and brown trout, Salmo trutta 

L. Aquacult. Fish. Manag. 23:489–498.

Boulder placement. Restoration of the river bottom with blasted stones provided 

salmon with more substrate spaces. Densities of trout increased after the river 

bank was covered with stones. Sediments transported downstream from the 

canalized river stretch decreased the densities of juvenile salmon and trout. 

Density estimates were seven fish per 100 m2 prior to draining. After restoration, 

densities of juvenile salmon varied from 25 to 125 fish per 100 m2.

Jähnig, S. C., K. Brabec, et al. 2010. A 

comparative analysis of restoration measures 

and their effects on hydromorphology and 

benthic invertebrates in 26 central and 

southern European rivers. J. Appl. Ecol.

47:671–680.

Hydromorphology and invertebrates. Mean Shannon-Wiener indices for both 

mesohabitats (1–1 nonrestored, 1–7 restored) and microhabitats (1–0 nonrestored, 

1–3 restored), while Shannon-Wiener indices for invertebrate communities were 

not significantly different (2–4 nonrestored, 2–3 restored).
76

Jester, D. B., and H. J. McKirdy. 1966. 

Evaluation of trout stream improvement in 

New Mexico. Proc. Annu. Conf. Western 

Assoc. State Game Fish Comm. 46:316–333.

Logs and boulders. A mean increase of 3.5 feet in width provided 36 additional 

acres of water. Increase of approximately 3′′ in mean depth and volume has 

almost doubled from 639 to 1,226 acre feet. Minor changes in water temperature

occurred. Silt caused significant decreases in depth of pools on the upstream side 

of structures in six of 32 streams observed. Increases of invertebrates were found 

at 14 stations, no change at two, and decreases at two. Thirty-six additional acres 

of water have provided habitat for stocking increase of 6,840 lb or 34,200 

rainbow trout annually. Overwinter survival was enhanced by presence of 

structures. Of 122 tagged fish, 97 were recaptured at the release sites, 19 moved 

past one structure, 5 moved past two structures, and 1 moved past three

structures. Total spread from this movement was approximately 300 feet. Mean 

catch rate in all 11 streams and sections has increased from .79 to .89 trout per 

man-hour. Water temperature increased at six of 16 stations and remained stable 

or decreased at 10 stations in eight streams. Mean temperature in all eight

streams decreased 2°F. No change in chemical composition.

Johnson, S. L., J. D. Rodgers, et al. 2005. 

Effects of an increase in large wood on 

abundance and survival of juvenile salmonids 

(Oncorhynchus spp.) in an Oregon coastal 

stream. Can. J. Fish. Aquat. Sci. 62(2):412–

424.

Large woody debris. Steelhead smolt abundance, steelhead freshwater survival, 

and coho salmon freshwater survival increased in one creek after the input of 

wood. Steelhead age 0+ summer populations and steelhead smolt populations 

increased in the reference stream, although steelhead freshwater survival did not. 

Coho salmon populations remained unchanged in the reference stream. The 

number of key pieces of wood increased from 7.1 pieces km−1 in the pretreatment 

count to 38.8 pieces km−1 in the post-treatment count. The increase was observed 

in all four reaches in the main stem, where the number of key pieces increased 2.5 

times in Reach 1, 5.7 times in Reach 2, 7.4 times in Reach 3, and 10.4 times in 

Reach 4. Results illustrate the potential shortcomings of the before-after controlimpact design under field conditions and the potential for misinterpreting results.
77

Jones, N. E., and W. M. Tonn. 2004. Enhancing 

productive capacity in the Canadian Arctic: 

Assessing the effectiveness of instream habitat 

structures in habitat compensation. Trans. 

Am. Fish. Soc. 133:1356–1365.

Boulders. Structures attracted significantly higher densities of Arctic grayling 

than did nearby reference sections, yet age-0 Arctic grayling at the structures did 

not experience any density-dependent reduction in growth, suggesting that 

structures provided energetically favorable microhabitats. Relative to reference

streams and prestructure conditions, the addition of these physical structures did 

not increase the density, biomass, or growth rates of age-0 Arctic grayling in the 

artificial stream as a whole.

Kasahara, T., and A. R. Hill. 2006a. Effects of 

riffle-step restoration on hyporheic zone 

chemistry in N-rich lowland streams. Can. J. 

Fish. Aquat. Sci. 63(1):120–133.

The effect of constructed riffles and a step on hyporheic exchange flow and 

chemistry in restored reaches of several nitrate-rich agricultural and urban 

streams. Hydrometric data collected from a network of piezometers and 

conservative tracer releases indicated that the constructed riffles and steps were 

effective in inducing hyporheic exchange. However, despite the use of cobbles 

and boulders in the riffle construction, high stream dissolved oxygen

concentrations were depleted rapidly with depth into the hyporheic zones. 

Differences between observed and predicted nitrate concentrations based on 

conservative ion concentration patterns indicated that these hyporheic zones were 

also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of 

interstitial fines in the restored cobble-boulder layers suggest that siltation and 

clogging of the streambed may reduce the downwelling of oxygen- and nitraterich stream water. Increases in streambed dissolved oxygen levels and 

enhancement of habitat for hyporheic fauna that result from riffle step 

construction projects may only be temporary in streams that receive increased 

sediment and nutrient inputs from urban areas and croplands.
78

Kasahara, T., and A. R. Hill. 2006b. Hyporheic 

exchange flows induced by constructed riffles 

and steps in lowland streams in southern 

Ontario, Canada. Hydrol. Process. 20:4287–

4305.

Riffle construction. The constructed riffles studied induced more extensive 

hyporheic exchange than the natural riffles because of their steeper longitudinal 

hydraulic head gradients and coarser streambed sediments. The depth of greater 

than 10% stream water zone in a small and a large constructed riffle extended to 

greater than 0•2 m and greater than 1•4 m depths respectively. Flux and 

residence time distribution of hyporheic exchange were simulated in constructed 

riffles. Hyporheic flux and residence time distribution varied along the riffles, 

and the exchange occurring upstream from the riffle crest was small in flux and 

had a long residence time. In contrast, hyporheic exchange occurring 

downstream from the riffle crest had a relatively short residence time and 

accounted for 83% and 70% of total hyporheic exchange flow in a small and large 

riffle, respectively. Although stream restoration projects have not considered the 

hyporheic zone, data indicate that constructed riffles and steps can promote 

vertical hydrologic exchange and increase the groundwater–surface water linkage 

in degraded lowland streams.

Keim, R. F., A. E. Skaugset, et al. 2000. 

Dynamics of coarse woody debris placed in 

three Oregon streams. For. Sci. 46(1):13–22.

Coarse woody debris (CWD). Treatment immediately increased CWD by 86% to 

155%. Although there was more CWD during the 3 years after treatment then 

there had been before, rates of movement were high. Aggregation of CWD 

increased in all three streams for at least 1 year and accumulations associated 

with key pieces were larger after 3 years than immediately after treatment. 

Pulled-over alders were more stable and more effective in forming accumulations 

than bucked conifers, but were subject to rapid decay.
79

Kelly, F. L., and J. J. Bracken. 1998. Fisheries 

enhancement of the Rye Water, a lowland 

river in Ireland. Aquat. Conserv.: Mar. 

Freshw. Ecosyst. 8(1):131–143.

Boulders. There was little change in the overall mean brown trout density (all 

ages excluding 0+) and standing crop in the enhancement section. There was a 

mean decrease in density of 18% in the control sections compared with a mean 

increase of 21% in the experimental sections, and a mean increase in biomass of 

11% in control and increase of 23% in experimental. This mean increase in 

density and biomass in the enhancement sections was due to an increase in the 

number of 2+ and 3+ brown trout and a decrease in 1+ fish. There was a 

significant overall mean increase of 152% in salmon density in the experimental 

sections, compared to a mean increase of 36% in the control. Increase in salmon 

density ranged from 25% to 300%. There was an overall mean increase of 219% 

in salmon biomass in the experimental sections, compared to an increase of 88% 

in the control. Increase in biomass in experimental sites ranged from 75% to 

390%. Drought affected physical variables, but mean water depths were lower at 

seven sites postworks. Results indicate that the channel became deeper at six of 

nine sites due to increase in the number of pools. Velocity and discharge values 

were lower at all cross sections, while maximum depth increased at all sites.

Kennedy, G. J. A., and P. M. Johnston. 1986. A 

review of salmon (Salmo salar L.) research on 

the River Bush. In W. W. Crozier and P. M. 

Johnson (eds.), Proceedings of the 17th 

Annual Study Course, p. 49–69. Univ. Ulster, 

Institute of Fisheries Management, Coleraine, 

UK.

Atlantic salmon. Areas that were drained 20–30 years prior by straightening the 

river channel and removing the substrate had very low densities of salmonids 

compared to undrained areas. After re-stoning, there was a highly significant 

correlation of total fish densities to the proportion of the substrate comprised of 

stones greater than 10 cm diameter at each site. There was no significant 

correlation of total fish density to water depth within the narrow range of site 

depths investigated. Following restocking of salmon fry, the mean survival was 

more than four times greater in the control sites (mean density 33.8 per 100 m−2) 

than in the drained sites (mean density 7.5 per 100 m−2).
80

Klassen, H. D. 1991. Operational stream 

rehabilitation trial at Clint Creek, Sewell Inlet. 

Land Management Rep. No. 68. Ministry of 

Forests, Victoria, BC.

Large woody debris. No significant changes in stream width. Number of pools 

in the thalweg increased from four before rehabilitation to 18 after and to 13 

pools 7 months later. Several sediment lobes dispersed with rehabilitation, 

resulting in a more constant streambed slope gradient of 2.9% vs. 2.0–4.7% 

before. There was a 23% reduction in wetted area, but pool area more than 

doubled after rehabilitation. There was a reduction of the majority of 

overhanging vegetation. Critical overwinter rearing habitat tripled and habitat 

diversity more than doubled. Fifty percent of the logs were underscoured, 

reducing average pool depths but also adding diversity. Sediment storage areas 

averaging approximately 14 m2 per log developed over the winter. Streambank 

erosion from rehabilitation averaged 1 m per log.

Klassen, H. D., and T. G. Northcote. 1988. Use 

of gabion weirs to improve spawning habitat 

for pink salmon in a small logged watershed.

N. Am. J. Fish. Manag. 8(1):36–44.

Gabions. Improvement of intragravel dissolved oxygen depression was 

significant (5.4 mg/L before to 2.5 mg/L after). Intragravel permeability also 

improved significantly in the low-gradient (1%) reaches, from 870 cm/hr to 2,400 

cm/hr after installation. Pink salmon egg survival at one site in its first year did 

not differ significantly from two nearby reference sites.

Knaepkens, G., L. Bruyndoncx, et al. 2004. 

Spawning habitat enhancement in the 

European bullhead (Cottus gobio), an 

endangered freshwater fish in degraded 

lowland rivers. Biodivers. Conserv.

13(13):2443–2452.

Tiles as artificial spawning substrate. Tiles were successfully used by European 

bullhead for spawning . Of the 100 recovered tiles, 69 had one egg cluster, 25 

tiles had two clusters, three tiles had three clusters, two tiles had four clusters, and 

one tile had five egg clusters, indicating a 30% use of recovered tiles as spawning 

substrate. In the meandering parts of the river, the number of egg deposits was 

significantly positively correlated with water depth, while in canalized areas, 

water depth and velocity were of no importance for tile usage.

Koljonen, S., A. Huusko, et al. 2012. Body 

mass and growth of overwintering brown trout 

in relation to stream habitat complexity. River 

Res. Appl. 28(1):62–70.

Brown trout. Channelized vs. seminatural streams. Fish of both age-classes (age0 and age-1) lost mass early in the winter, but age-0 fish in the channelized 

streams lost more of their initial mass than did the restored stream fish (10% vs. 

2.5% on average, respectively). By early spring, they caught up for their greater 

initial mass loss. The shortage of suitable sheltering sites in channelized streams 

apparently intensified competition and caused greater initial mass loss in age-0 

trout. Growth compensation may have negative impacts on the long-term fitness 

of juvenile trout.
81

Kondolf, G. M., J. C. Vick, et al. 1996. Salmon 

spawning habitat rehabilitation on the Merced 

River, California: An evaluation of project 

planning and performance. Trans. Am. Fish. 

Soc. 125:899–912.

Riffle reconstruction with gravel. In the planning phase, there was no 

consideration to geomorphic context or erosion and sediment transport. Hence

the gravel placed in the channel was scoured and transported with a return period 

of 1.5 years. The project design greatly simplified the physical habitat need of 

spawning salmon. Estimated mean annual redds over its expected 15-year life 

was 120. Actual counts from 1990 to 1994 were 16, 8, 41, 46, and 56,

respectively.

Korsu, K. 2004. Response of benthic 

invertebrates to disturbance from stream 

restoration: The importance of bryophytes.

Hydrobiologia 523(1–3):37–45.

Boulders. Response of invertebrates to disturbance. Restoration procedure 

destroyed nearly half of the bryophytes present in the study reach and invertebrate

densities decreased sharply immediately after restoration (total number reduced 

by 50% on day 1 and 83% on day 4). Within 2 weeks, invertebrates had 

recolonized the disturbed reach and, within 1 month, peak numbers were attained. 

Invertebrates showed a clear association with bryophytes, especially after 

restoration.

Laasonen, P., T. Muotka, et al. 1998. Recovery 

of macroinvertebrate communities from 

stream habitat restoration. Aquat. Conserv.: 

Mar. Freshw. Ecosyst. 8(1):101–113.

Boulder dams/flow deflectors. Water depth and current velocity were lower and 

relative bed roughness higher in restored than in dredged channels. Moss cover 

was negligibly low in recently restored streams, but mosses had recovered well 

within 3 years of restoration. The standing stock of leaf litter was lower than in 

natural streams, but mostly higher than in channelized streams. Abundances of 

all invertebrates were highest in natural streams and lowest in streams restored 1 

month before sampling. All other restored streams had abundances comparable 

to or slightly lower than those in channelized streams. There was a tendency 

toward higher abundances of shredders with a long recovery period, but streams 

restored 8 or 16 years ago still contained relatively sparse shredder populations. 

Enhanced litter retention increases the capacity of restored streams to support 

high abundances of detritivorous invertebrates. Abundances of shredders as well 

as other detritivores were indeed higher in streams restored a few years ago than 

in recently restored streams.
82

Lacey, R. W. J., and R. G. Millar. 2004. Reach 

scale hydraulic assessment of instream 

salmonid habitat restoration. J. Am. Water 

Resour. Assoc. 40(6):1631–1644.

Large woody debris and rock groyne. 2-D flow model velocity and depth 

predictions compare favorable to measured field values with mean SEs of 24% 

and 6%, while areas of predicted high shear coincide with the newly formed pool 

locations. At high flows, the fish habitat index used (weighted usable area) 

increased by 150% to 210%. The most beneficial aspect of instream structures is 

to increase preferred habitat areas during high flow events for steelhead and coho

salmon fry and juveniles. Structures create low velocity zones on their 

downstream sides where fish can hold and rest.

Laitung, B., J. L. Pretty, et al. 2002. Response 

of aquatic hyphomycete communities to 

enhanced stream retention in areas impacted 

by commercial forestry. Freshw. Biol. 

47(2):313–323.

Large woody debris. The average concentration of fungal spores in reference

sections was nearly 10 times greater in French streams than in English. The 

number of hyphomycete species was also higher in French streams. The 

difference was probably because of the much lower standing stock and diversity 

of leaf litter in the English streams. The treatment had a clear effect in all 

streams. Detrital standing stocks were enhanced in treated sections by up to 90% 

in French and 70% in English streams. Mean spore density below treated 

sections increased by 1.8–14.8% in French and 10.2–28.9% in English. Large 

woody debris can increase detritus retention and enhance hyphomycete diversity 

and productivity.

Larson, M. G., D. B. Booth, et al. 2001. 

Effectiveness of large woody debris in stream 

rehabilitation projects in urban basins. Ecol. 

Eng. 18:211–226.

Large woody debris (LWD). Pool spacing narrowed after LWD installation. All 

project sites exhibited fewer pools for a given LWD loading, however, than has 

been reported for forested streams. Only limited success was observed 

controlling downstream sedimentation. None of the sites had any detectable 

improvement in biological conditions due to the addition of LWD. In all but one 

stream, sediment storage associated with LWD increased by 50–100% where 

LWD frequently increased. Added LWD contributed most to grade control (11–

23%) on the highest gradient streams where wood spanned the full width of the 

channel, but contributed little to grade control on low-gradient streams.
83

Latta, W. C. 1972. The effects of stream 

improvement upon the anglers catch and 

standing crop of trout in the Pigeon River, 

Otsego County, Michigan. Michigan Dept.

Natural Resources, Ann Arbor.

Large woody debris. An assessment of movement indicated little interchange of 

trout with the water outside the experimental area, but substantial interchange 

between sections. There was a consistent increase of brook trout when the 

structures were in the stream. For brown trout, there appeared to be a steady 

increase before, during, and after, independent of the addition or removal of 

structures. For brook trout, a statistically significant increase occurred in 

numerical catch, in fall standing crop, in fall standing crop plus catch, and in 

numbers of age-1 and older fish. There was a decline in the area of water more 

than 3 feet deep and decline in the amount of cover, but little or no change in 

bottom soil types.

Lawrence, J. E., V. H. Resh, et al. 2013. Large 

wood loading from natural and engineered 

processes at the watershed scale. River Res. 

Appl. 29(8): 1030–1041.

Fish response not reported. Natural vs. engineered large wood loading. The 

amount of large wood in the bankfull channel and the amount available for 

recruitment from the 10-year floodplain were highly variable among and within 

reaches and largely dependent on the local geomorphic setting. Reaches with 

engineered wood structures had elevated pool frequencies, suggesting a higher 

capacity to support salmonids during critical life stages. Among wood pieces that 

had a strong influence on pool formation, 23% had an attached root wad and 66% 

were part of a cluster. All reaches had lower volumes of large wood in their 

bankfull channels than similar stream types with natural wood-loading levels.

Lehane, B. M., P. S. Giller, et al. 2002. 

Experimental provision of large woody debris 

in streams as a trout management technique.

Aquat. Conserv.: Mar. Freshw. Ecosyst.

12(3):289–311.

Large woody debris. Brown trout. Wood created more suitable habitat for trout 

through development of additional pools in which beds of fine sediment 

developed and constraining the current, increasing the amount of eddies and slack 

water areas. There were significant increases in trout density and biomass in the 

debris segments relative to controls, although trout condition was not modified by 

the addition of large woody debris. Pool habitat increased from 16% of total 

surface area to 35%; riffles decreased from 31% to 25%. Preinstallation (March 

1998) fish survey had 664 trout in two reaches; postsurveys captured 1,170 (Sept. 

1998), then 670 (1999), and finally 523 (2000). Recapture rates suggest that loss 

rates over time appear to be lower in debris segments.
84

Lemly, A. D., and R. H. Hilderbrand. 2000. 

Influence of large woody debris on stream 

insect communities and benthic detritus.

Hydrobiologia 421(1):179–185.

Large woody debris (LWD). After LWD additions, total area occupied by pools 

more than doubled (from 222 m2 to 546 m2) concurrent with a 42% decrease in 

riffle area (from 768 m2 to 443 m2

). Pools contained significantly more benthic 

detritus than riffles but showed no post-treatment response of LWD relative to the 

reference section. Net benthic detritus in riffles decreased by 14.3 kg after LWD 

additions, dropping from 71.6 in 1993 down to 57.3 kg in post-treatment 1994. 

Community structure based on functional feeding groups was similar both 

spatially and temporally between treatment sections for pools, and was spatially 

similar for riffles in 1993, but differed significantly between years in riffles.

Lepori, F., D. Palm, et al. 2005a. Does 

restoration of structural heterogeneity in 

streams enhance fish and macroinvertebrate 

diversity? Ecol. Appl. 15(6):2060–2071.

Boulders. At both the reach and patch scale, structural heterogeneity was 

substantially higher at restored than at channelized sites, although differences in 

between-patch variation were not significant. Restored sites had higher total fish 

biomass relative to channelized sites. Higher total biomass at restored sites 

reflected higher numbers of individuals due to more habitat availability rather 

than increased fish density or individual fish biomass. The components of 

diversity assessed for invertebrates were comparable between restored and 

channelized sites. Despite substantial differences in heterogeneity across 

different spatial scales, most components of fish and invertebrate diversity were 

similar between restored and channelized sites.

Lepori, F., D. Palm, et al. 2005b. Effects of 

stream restoration on ecosystem functioning: 

Detritus retentiveness and decomposition.

J. Appl. Ecol. 42(2):228–238.

Boulders. Coarse particulate organic matter (CPOM) retentiveness reflected most 

strongly the density of boulders and submerged woody debris at the study sites. 

Restored sites were on average twice as retentive as channelized sites and 

significantly more retentive than reference sites when discharge was controlled. 

Current velocity at bankfull flow was the single most important predictor of 

CPOM mass loss. Other apparent controls of CPOM breakdown included water 

temperature and shredder abundance. CPOM mass loss was similar between 

restored and reference sites, however, breakdown was slightly faster at most 

channelized sites.
85

Lester, R. E., and W. Wright. 2009. 

Reintroducing wood to streams in agricultural 

landscapes: Changes in velocity profile, stage,

and erosion rates. River Res. Appl.

25(4):376–392.

No fish. Reintroducing wood in streams to measure velocity profile, stage, and 

erosion rates. There was no clear evidence of longer term rates of erosion or 

flooding associated with the introduction of wood to streams over the study 

period. There was a lack of adverse effects on stream morphology and increased 

variability of the instream environment, suggesting improved habitat diversity.

Linlokken, A. 1997. Effects of instream habitat 

enhancement on fish population of a small 

Norwegian stream. Nord. J. Freshw. Res.

73:50–59.

Weirs. The mean density of brown trout in the experimental section was 18.3 per 

100 m prior to enhancement, and increased by 200% after weir construction. The 

increase was due to increased number of specimens greater than 10 cm, whereas 

number of fish less than 10 cm decreased.

Lonzarich, D. G., and T. P. Quinn. 1995. 

Experimental evidence for the effect of depth 

and structure on the distribution, growth, and 

survival of stream fishes. Can. J. Zool.

73:2223–2230.

Large woody debris. Mortality (likely due to bird predation) of water-column 

species using the simplest habitat type was a much as 50% greater than in other 

treatments. Coastrange sculpin used deep pools more frequently than shallow 

pools by a ratio of nearly 3 to 1. Yearling cutthroat trout and steelhead were 

almost never collected in shallow pools—100% of cutthroat and 83% of steelhead 

were found in two deepwater treatments. Habitat selection by age-0 trout was 

strongly associated with structure, as fish were three times more abundant in 

structured (75%) than in unstructured treatments (25%). Age-1+ cutthroat trout 

and coastrange sculpin were positively associated with deep-water habitat, age-0 

trout were associated with structure, and age-1+ steelhead and coho salmon were 

associated with both. Coho (16%) and age-0 steelhead (21.5%) showed the 

greatest gains in growth; coastrange sculpin were next (10.8%), followed by age1+ steelhead (9.9%). Coho salmon survival was greatest in the deep and 

structured treatment (89%), nearly twice that in the shallow, no-structure 

treatment (47%). Both age-0 and age 1+ steelhead showed higher survival in the 

deep-structure treatment (71% and 89%) than in the shallow-nonstructures 

treatment (29% and 33%, respectively). Water depth appeared to be more 

important than structure in determining the distribution of large age-1+ cutthroat 

trout and steelhead, while structure alone (age-0 trout) or both structure and depth 

(coho salmon) were important for the small salmonids.
86

Louhi, P., H. Mykra, et al. 2011. Twenty years 

of stream restoration in Finland: Little 

response by benthic macroinvertebrate 

communities. Ecol. Appl. 21(6):1950–1961.

Following treatment, invertebrate densities decreased in all treatments, but less so 

in the controls. Taxonomic richness also decreased. In the long-term 

comparative study, invertebrate species richness shows no difference between the 

channel types. Community composition differed significantly between the 

restored and natural streams, but not between restored and channelized streams. 

Overall, restoration measures increased stream habitat diversity, but did not 

enhance benthic biodiversity.

Lyons, J., and C. C. Courtney. 1990. A review 

of fisheries habitat improvement projects in 

warm water streams, with recommendations 

for Wisconsin. Tech. Bull. No. 169. 

Wisconsin Dept. Natural Resources, Madison.

Case studies. Little specific information. Five recommendations for habitat 

improvements. Large woody debris and boulders. Some studies showed 

increases in fish, some with no change, and a few with decreases.

MacInnis, C., T. A. Floyd, et al. 2008. Large 

woody debris structures and their influence on 

Atlantic salmon spawning in a stream in Nova 

Scotia, Canada. N. Am. J. Fish. Manag.

28(3):781–791.

Atlantic salmon. Redd counts increased for the first 4 years after restoration from 

43 in 1992 to 592 in 1996. After that, redd counts remained high (502–605) but 

no longer increased. In 2004 reaches with structures had significantly more redds 

(366) than reaches without (280). In reaches with artificial structures, 48% of 

redds were associated with gravel pool tails or the heads of riffles, 44% were near 

artificial structures, and 7% were near natural large woody debris. In reaches 

without artificial structures, almost 89% of the redds were associated with pool 

tails and the remainder were associated with natural large woody debris.

McCubbing, D. J. F., and B. R. Ward. 1997. 

The Keogh and Waukwaas rivers paired 

watershed study for B.C.’s Watershed 

Restoration Program: Juvenile salmonid 

enumeration and growth 1997. Ministry of 

Environment, Lands, and Parks and Ministry 

of Forests, Vancouver, BC.

Large woody debris, boulders, nutrients. Complex lateral debris jams had highest 

coho salmon fry densities (mean = 80 fry per 100 m2), while boulder clusters had 

greatest steelhead parr abundance (mean = 6 parr per 100 m2

) or average of one 

parr per boulder. However, results were not significantly different statistically 

among habitat structures. Riffles were associated with higher steelhead parr 

numbers and shallow pools with higher coho fry numbers. Growth data, in 

summer and early fall size, indicated improved length (5–10 cm) and weight 

(>30%) of coho fry and steelhead fry in fertilized areas compared to untreated 

areas.
87

McCubbing, D. J. F., and B. R. Ward. 2000. 

Stream rehabilitation in British Columbia’s 

Watershed Restoration Program: Juvenile 

salmonid response in the Keogh and 

Waukwaas rivers 1998. Ministry of 

Environment, Lands, and Parks and Ministry 

of Forests, Vancouver, BC.

Large woody debris (LWD), nutrients, boulders. Significant increases were 

found in steelhead parr and fry abundance and coho salmon fry abundance overall 

at the watershed level and in reaches treated with structures, compared to 

untreated controls within and between watersheds, despite low levels of adult 

escapement. A diversity of structural types appears to provide an optimum 

strategy for habitat rehabilitation, rather than singular types. Significantly larger 

salmonids were found in fertilized sections. Relative steelhead parr abundance 

was higher in 1998 than in 1997 by an average increase of 20 parr per 100 m 

within reaches of the Keogh, a mean increase of 110%. In contrast, three of four

sample reaches on the Waukwaas River showed reductions in parr abundance (a 

mean of 30% reduction for all reaches) to levels which were not significantly 

different that those in the Keogh. Coho salmon fry densities were lower in both 

watersheds compared to 1997 data, except in the uppermost reaches of both 

watersheds. Coho fry were most abundant in pool and complex LWD habitat 

while steelhead fry were associated with run and flat habitat, regardless of LWD 

presence. Steelhead and coho parr were found in low numbers in pool habitat and 

some flats, particularly when LWD was present.

Merz, J. E., and L. K. O. Chan. 2005. Effects 

of gravel augmentation on macroinvertebrate 

assemblages in a regulated California river.

River Res. Appl. 21(1):61–74.

Gravel. Placement of cleaned floodplain gravel decreased depths and increased 

stream velocities. Benthic organisms colonized new gravels quickly, equaling 

densities and biomass of unenhanced spawning sites within 4 weeks. 

Macroinvertebrate species richness equaled that of unenhanced sites within 4 

weeks and diversity within 2 weeks. Standing crop, as indicated by densities and 

dry biomass, was significantly higher in enhancement sites after 12 weeks than in 

unenhanced sites and remained so over the following 10 weeks. Although mobile 

collector/browsers initially dominated new gravels, sedentary collectors were the 

most common feeding category after 4 weeks, similar to in unenhanced sites.
88

Merz, J. E., and J. D. Setka. 2004. Evaluation 

of a spawning habitat enhancement site for 

Chinook salmon in a regulated California 

River. N. Am. J. Fish. Manag. 24(2):397–

407.

Gravel. The project significantly increased channel water velocities, intergravel 

permeability, and dissolved oxygen; reduced channel depths; and equilibrated 

intergravel and ambient river temperatures. The benefits remained throughout the 

30-month monitoring period. Adult Chinook salmon began spawning at the 

previously unused site within 2 months after gravel placement and continued to 

use the site during the three spawning seasons encompassed by the study. 

Average bed elevation increased by .12 m and average velocities increased by .24

m/s.

Merz, J. E., J. D. Setka, et al. 2004. Predicting 

benefits of spawning-habitat rehabilitation to 

salmonid (Oncorhynchus spp.) fry production 

in a regulated California river. Can. J. Fish. 

Aquat. Sci. 61(8):1433–1446.

Gravel. Salmon embryos planted in enhanced gravels had higher rates of survival 

to the swim-up stage than embryos planted in unenhanced spawning gravels. No 

significant increase in growth was observed. Intergravel temperature and 

substrate size were strongly correlated with distance downstream from the lowest 

nonpassable dam. Intergravel turbidity and total suspended and volatile solids 

were also strongly correlated. Survival models accounted for 87% of the 

variation around the mean for salmon and 82% for steelhead. Growth models 

accounted for 95% of the variation around the mean for salmon and 89% for 

steelhead.

Miller, S. W., P. Budy, et al. 2010. Quantifying 

macroinvertebrate responses to instream 

habitat restoration: Applications of metaanalysis to river restoration. Restor. Ecol. 

18(1):8–19.

No fish. Meta-analysis of 24 separate studies. Increasing habitat heterogeneity 

had significant, positive effects on macroinvertebrate richness, although density 

increases were negligible. Large woody debris produced the largest and most 

consistent responses, whereas responses to boulder additions and channel

reconfigurations were positive yet highly variable. On average, richness 

estimates in restored reaches were 14.2% greater than in unrestored control 

reaches and density estimates were 28% greater. On average, richness and 

density increases were greater for large woody debris than boulder additions, 83%

and 75%, respectively.

Miller, J. R., and R. C. Kochel. 2010. 

Assessment of channel dynamics, instream 

structures, and postproject channel 

adjustments in North Carolina and its 

implications to effective stream restoration.

Environ. Earth Sci. 59(8):1681–1692.

Summary of 26 studies. Not a lot of good numbers. Decrease in bank cohesion 

and increase in stream power makes for a high risk of erosion, given a moderate 

sediment supply. Change in channel capacity is highly variable from site to site, 

but more than 60% of projects on average underwent a 20% change in channel 

capacity.
89

Mitchell, J., R. S. McKinley, et al. 1998. 

Evaluation of Atlantic salmon parr responses 

to habitat improvement structures in an 

experimental channel in Newfoundland, 

Canada. Regul. Rivers: Res. Manag.

14(1):25–39.

Boulders. Results showed that the midchannel treatment (boulder cluster and a 

low-head barrier dam) did not serve its purpose at lower discharges. However, as 

the discharge increased, more salmon took up residence in this treatment. In all 

experiments, greater depths were selected in the streambank treatment, and 

salmon parr in the midchannel treatment consistently selected positions closer to 

cover. Large parr preferred greater depths and were found closer to the 

improvement structures. Funneling effects of the drift were created near 

structures. The average number of fish counted decreased as the discharge 

increased. No significant differences were found in the densities of benthic 

invertebrates in each replicate or treatment. The drift in the channel was 

significantly different than the drift in the reference site.

Moore, K. M. S., and S. V. Gregory. 1988. 

Response of young-of-the-year cutthroat trout 

to manipulation of habitat structure in a small 

stream. Trans. Am. Fish. Soc. 117(2):162–

170.

Large woody debris. Cutthroat trout. Young-of-the-year fish were virtually 

eliminated from stream sections with reduced area of lateral habitat. In the first 

census following emergence, the average numbers of age-0 fish per 15 m section 

were 26.7 in the increased-lateral-habitat treatment, 13.3 in the control treatment, 

and 3.0 in the reduced-lateral-habitat treatment. The difference between 

treatments was highly significant at each observation date. In the increasedlateral-habitat sections, a 2.4-fold increase in area of lateral habitat resulted in a

2.2-fold increase in the average number of age-0 fish. Straightening stream 

sections reduced the area of lateral habitat 86% and resulted in an 83% reduction 

in average number of age-0 cutthroat trout.

Moreau, J. K. 1984. Anadromous salmonid 

habitat enhancement by boulder placement in 

Hurdygurdy Creek, California. In T. J. 

Hassler (ed.), Proceedings: Pacific Northwest 

Stream Habitat Management Workshop, p. 

97–116. Humboldt State Univ., Arcata, CA.

Steelhead and Chinook salmon. Population estimates for steelhead parr increased 

by 100% 2 years after boulder placement in one stream section, while estimates in 

two control sections declined by 56% and 61%. Large areas of spawning gravel 

were created, increases in both steelhead parr habitat and gravel spawning areas 

were attained, and costs ranged from $41 to $77 per m3

.
90

Morley, S. A., J. D. Toft, et al. 2012. 

Ecological effects of shoreline armoring on 

intertidal habitats of a Puget Sound urban 

estuary. Estuar. Coasts 35(3):774–784.

Fourteen fish species. Mean substrate temperatures were significantly warmer at 

armored sites, but water temperature was similar to unarmored habitats. 

Epibenthic invertebrate densities were more than 10 times greater on unarmored 

shorelines and taxa richness double that of armored locations. Taxa richness of 

neuston invertebrates was also higher at unarmored sites, but abundance was 

similar. There was no difference in Chinook salmon diet, but a higher proportion 

of benthic prey for chum salmon was observed from unarmored sites.

Mueller, G., and C. R. Liston. 1994. Use of 

low-profile artificial cover to enhance 

fisheries found in concrete lined irrigation 

canals, Arizona-California. Bull. Mar. Sci.

55(2–3):1347.

Abstract only. Low-profile artificial reefs. Fish and invertebrate data indicated 

reefs significantly benefitted aquatic organisms. Fish species diversity increased

by 120% and abundance was 20 times greater than at control sites. No species 

named.

Muotka, T., and P. Laasonen. 2002. Ecosystem 

recovery in restored headwater streams: The 

role of enhanced leaf retention. J. Appl. Ecol.

39(1):145–156.

Boulders. Leaf retention. Substrate heterogeneity increased by moss cover 

decreased dramatically. Retention efficiency in restored streams was higher than 

in channelized, but lower than in natural streams. Algae-feeding scrapers were 

the only macroinvertebrate whose density increased significantly: three times

higher in restored than in channelized streams.

Muotka, T., R. Paavola, et al. 2002. Long-term 

recovery of stream habitat structure and 

benthic invertebrate communities from 

instream restoration. Biol. Conserv.

105(2):243–253.

Boulders/gravel. Invertebrate communities in unmodified streams changed little, 

whereas those in restored streams had undergone considerable changes.

Nagayama, S., F. Nakamura, et al. 2012. 

Effects of configuration of instream wood on 

autumn and winter habitat use by fish in a 

large remeandering reach. Hydrobiologia 

680(1):159–170.

Twelve fish species including rainbow trout, chum salmon, masu salmon, and 

white-spotted charr. No good numbers. Fish diversity was higher at the simple 

wood structure (SWS) and the logjam (LJ) sites than in the no-wood (NW) sites

during both seasons (autumn and winter). Diversity at the LJ sites was higher 

than at the SWS sites during the winter. The abundance of the four dominant fish 

species was generally higher at the LJ sites than at the NW sites during both 

seasons. The SWS and LJ sites had greater depths, finer bed material, and more 

diverse flow conditions during autumn. During the winter, the LJ sites had 

slower currents and finer bed materials.
91

Naslund, I. 1989. Effects of habitat 

improvement on the brown trout, Salmo trutta 

L., population of a northern Swedish stream. 

Aquacult. Fish. Manag. 20:463–474.

Boulders and logs. Boulder dams increased brown trout densities by up to three

times and standing crop by up to five times. Log deflectors gave similar effects 

on standing crop while boulder groupings and boulder deflectors seemed to be 

inefficient.

Negishi, J. N., and J. S. Richardson. 2003. 

Responses of organic matter and 

macroinvertebrates to placements of boulder 

clusters in a small stream of southwestern 

British Columbia, Canada. Can. J. Fish. 

Aquat. Sci. 60:247–258.

Boulder clusters. Mean velocity and its coefficient of variation increased 140%

and 115%, respectively. Enhanced particulate organic matter storage (550%) was 

accompanied by increased total invertebrate abundance (280%). Effect of 

boulder clusters on taxonomic richness was negligible.

Newbury, R., and M. Gaboury. 1988. The use 

of natural stream characteristics for stream 

rehabilitation works below the Manitoba 

escarpment. Can. Water Resour. J. 14(4):35–

51.

Riffles and boulders. Based on egg density measurements, more walleye 

spawned on the paired riffles (3.6 eggs/sq. mile) than on the single riffles (1.1 

eggs/sq. mile). The number of newly hatched walleye larvae caught below paired 

riffles was significantly greater than the number caught below any single riffles.

Newbury, R., and M. Gaboury. 1993. 

Exploration and rehabilitation of hydraulic 

habitats in streams using principles of fluvial 

behaviour. Freshw. Biol. 29(2):195–210.

Riffles and boulders. Walleye, brook trout, and rainbow trout. Inconclusive 

results.

Nickelson, T. E., M. F. Solazzi, et al. 1992. 

Effectiveness of selected stream improvement 

techniques to create suitable summer and 

winter rearing habitat for juvenile coho 

salmon (Oncorhynchus kisutch) in Oregon 

coastal streams. Can. J. Fish. Aquat. Sci.

49(4):790–794.

Log, gabion, and rock. When placed across the full stream width, structures 

provided good summer habitat but poor winter habitat for juvenile coho salmon. 

No numbers.
92

Nicol, S. J., J. A. Lieschke, et al. 2004. 

Observations on the distribution and 

abundance of carp and native fish, and their 

responses to a habitat restoration trial in the 

Murray River, Australia. New Zealand J. 

Mar. Freshw. Res. 38(3):541–551.

Large woody debris (LWD). Carp and native fish. Little support that 

competition for LWD habitat has population level effects; there was a statistically

significant relationship between native fish, LWD, and location within a meander 

and curvature of the meander. Carp response to LWD placement was 

inconclusive.

O’Grady, M. 1995. The enhancement of 

salmonid rivers in the Republic of Ireland. 

J. Chartered Institution Waters Environ. 

Manag. 9:164–172.

Boulders and brush removal. All numbers were estimates. Enhancement costs 

were estimated as £0.34–2.13 per fish caught on a rod and line. Shrub-pruning 

salmon production was estimated at ≥£0.24 per adult salmon returning to the river 

or ≥£1.5 per adult salmon caught on rod and line. Atlantic salmon and brown 

trout.

O’Grady, M. F., J. J. King, et al. 1991. The 

effectiveness of two physical instream works 

programmes in enhancing salmonid stocks in 

a drained Irish lowland river system. In D. 

Mills (ed.), Strategies for the rehabilitation of 

salmon rivers—Proceeding of a joint 

conference held at The Linnean Society, p. 

154–178. The Atlantic Salmon Trust, The 

Institute of Fisheries Management, and The

Linnean Society of London, London, UK.

Rubble and brush removal. Velocity increased (7.5 cm/s in control to 46.2 cm/s

in treatment). Depth decreased from 176.7 cm in control location to 34 cm in 

treatment with rubble mats.

Overton, K., W. A. Brock, et al. 1981. 

Restoration and enhancement program of 

anadromous fish habitat and populations on 

Six Rivers National Forest. In T. J. Hassler 

(ed.), Proceedings: Propagation, 

Enhancement, and Rehabilitation of 

Anadromous Salmonid Populations and 

Habitat in the Pacific Northwest Symposium, 

p. 158–168. Humboldt State Univ., Arcata, 

CA.

Boulders. Steelhead and Chinook salmon. Project resulted in a twofold and a 

fourfold increase in juvenile steelhead numbers in the boulder-only section and 

the boulder-log section, respectively. There was a marked increase in age 1+ 

steelhead in the treated section. Treatment reach increased 19% in surface area 

and streamflow volume increased 75% where boulders were placed in clusters. 

The increase in pool stilling area averaged 1.10 m3 per boulder. The increase in 

absolute biomass of 315% in treatment reach parr, boulder cluster section, was 

greater than the 256% and 143% increase in relative biomass per surface area and 

volume, respectively. Steelhead egg-to-fry survival ranged from 71% to 98%.
93

Palm, D., E. Brannas, et al. 2007. The influence 

of spawning habitat restoration on juvenile 

brown trout (Salmo trutta) density. Can. J. 

Fish. Aquat. Sci. 64:509–515.

Boulders. Brown trout. After restoration, density of age 0+ trout increased 

significantly in the boulder-plus-gravel section and was positively correlated with 

the area of reconstructed gravel beds. Percentage of age 0+ in the population 

increased from 36% to 51.5% after gravel bed restoration. The density of age 0+ 

trout did not change in the boulder-only treatment, whereas this same percentage 

declined from 27.9% to 23.4% in the boulder-only section. Egg-to-fry survival 

was significantly higher in the boulder-plus-gravel section compared to the 

boulder-only section, 10.3% (±2.6) vs. 1.7% (±1.1).

Paulsen, C. M., and T. R. Fisher. 2005. Do 

habitat actions affect juvenile survival? An 

information-theoretic approach applied to 

endangered Snake River Chinook salmon.

Trans. Am. Fish. Soc. 134(1):68–85.

Logs, boulders, etc. Model estimates only. There was a positive, significant 

correlation between actions and parr-to-smolt survival; however, there were also 

numerous significant correlations between survival, actions, and many of the 

potential independent variables.

Pess, G. R., M. C. Liermann, et al. 2012. 

Juvenile salmon response to the placement 

of engineered logjams in the Elwha River, 

Washington State, USA. River Res. Appl.

28(7):872–881. Online at http://dx.doi.org 

[DOI name 10.1002/rra.1481, accessed 12 

December 2013].

Chinook salmon, coho salmon, and trout. Juvenile salmonid density was higher 

in engineered logjam (ELJ) units for all control-treatment pairs except one in 

2002 and 2003. Positive mean differences in juvenile densities between ELJ and 

non-ELJ units were observed in 2 of 4 years for all juvenile salmon, trout greater 

than 100 mm, and juvenile Chinook salmon. Positive mean differences occurred 

in 1 of 4 years for juvenile coho salmon and trout less than 100 mm.
94

Peters, R. J., B. R. Missildine, et al. 1998. 

Seasonal fish densities near river banks 

stabilized with various stabilization methods.

U.S. Fish and Wildlife Service, Lacey, WA.

Summary of studies. No specific numbers. Examined seasonal fish densities at 

streambanks stabilized using riprap, riprap with large woody debris (LWD) 

incorporated into the project, rock deflectors, rock deflectors with LWD 

(combination projects), and LWD. LWD-stabilized sites were the only project 

types that consistently had greater fish densities than their control areas during 

spring, summer, and winter surveys. Riprap sites consistently had lower fish 

densities than their control sites during all surveys. Fish densities were generally 

lower at deflector sites than their controls during the spring and summer, but 

greater during the winter. Although large differences (between stabilized sites 

and controls) existed in some cases, the differences were rarely statistically 

significant due to high variation and small sample size. Instream LWD cover and 

overhead riparian cover were the habitat variables that most consistently 

influenced fish densities at stabilized and control sites surveyed. Fish densities 

were generally positively correlated with increasing surface area of LWD and 

increased overhead riparian cover within 30 cm of the water surface.

Pierce, R., C. Podner, et al. 2013. Response 

of wild trout to stream restoration over two 

decades in the Blackfoot River basin, 

Montana. Trans. Am. Fish. Soc. 142(1):68–

81.

Study of 18 projects and various techniques. Wild trout. At pretreatment 

conditions, average trout abundance was significantly lower in treatment vs. 

reference sites (0.19 vs. 0.62 trout/m). By 3 years after treatment, trout 

abundance had increased significantly to an average of 0.47 trout/m and was no 

longer significantly different from the reference average These initial rapid 

increases were sustained over 5–21 years in 15 streams. Although long-term (12 

years) average response trends were positive, trends varied spatially and native 

trout responded more strongly in the upper portion of the basin.

Poulin, V. A., and Associates Ltd. 1991. Stream 

rehabilitation using LWD placements and offchannel pool development. Ministry of 

Forests, Victoria, BC.

Large woody debris, gabion. Coho salmon, rainbow trout, and Dolly Varden

trout. Juvenile salmonid response to large organic debris structures was positive, 

with substantially increased densities after construction in two creeks (from 1% to 

210% and from 13% to 194% of control densities). Juvenile densities in blast 

pool sections of one tributary increased substantially after construction (from 

61% to 485%).
95

Pretty, J. L., and M. Dobson. 2001. A possible 

strategy for enhancing the stream biota in 

areas of intensive commercial forestry. Int. 

Assoc. Theor. Appl. Limnol. 27(2):1075–

1078.

Large woody debris. No numbers. Increases in detritus levels were slight, 

standing stocks remained very low, and the invertebrate fauna was unaffected.

Pretty, J. L., S. S. C. Harrison, et al. 2003. 

River rehabilitation and fish populations: 

Assessing the benefit of instream structures.

J. Appl. Ecol. 40(2):251–265.

Boulders and riffles. No numbers. There was little evidence that treatments 

substantially improved the conservation value of the fish assemblage in terms of 

abundance, species richness, diversity, and equitability. Bullhead (Cottus gobio) 

and stone loach.

Price, D. J., and W. J. Birge. 2005. 

Effectiveness of stream restoration following 

highway reconstruction projects on two 

freshwater streams in Kentucky. Ecol. Eng.

25(1):73–84.

Riprap, vegetation. Nonsalmonids (bass, sunfish, darters). No good numbers. A 

decrease in total habitat assessment scores was observed at the remediated sector 

in each stream. However, the Index of Biological Integrity fish assemblage 

scores were similar for upstream and remediated sectors, indicating that habitat 

impact resulted in limited effects on assemblages.

Pulg, U., B. T. Barlaup, et al. 2013. Restoration 

of spawning habitats of brown trout (Salmo 

trutta) in a regulated chalk stream. River Res. 

Appl. 29(2):172–182.

Brown trout. Both gravel addition and gravel cleaning proved to be suitable for 

creating spawning grounds. Fish reproduced successfully at all test sites. The 

relative number of young-of-the-year brown trout increased clearly after 

restoration. Sediment on the test sites collimated during the 4 years of the study. 

In the first 2 years, highly suitable conditions were maintained, with a potential 

egg survival of more than 50%. Afterwards, the sites offered moderate 

conditions—egg survival less than 50%. Conditions unsuitable for reproduction 

were expected to be reached in 5–6 years after restoration.

Purcell, A. H., C. Friedrich, et al. 2002. An 

assessment of a small urban stream restoration 

project in northern California. Restor. Ecol.

10(4):685–694.

No numbers. Both biological and habitat quality improved in the restored 

compared with the unrestored section, but the restored area was of lower quality 

than a stream restored 12 years before.

Quinn, J. W., and T. J. Kwak. 2000. Use of 

rehabilitated habitat by brown trout and 

rainbow trout in an Ozark tailwater river.

N. Am. J. Fish. Manag. 20(3):737–751.

Large woody debris and rocks. Brown, rainbow, brook, and cutthroat trout. 

Rainbow and brown trout accounted for most of the total trout density (87%) and 

biomass (97%) in the reference reach and modified reach (76% density, 90% 

biomass). Mean total trout density was 463 fish/ha (103 kg/ha) in the reference

reach and 1,854 fish/ha (252 kg/ha) in the modified reach.
96

Raborn, S.A., and H. L. Schramm Jr. 2003. 

Fish assemblage response to recent mitigation 

of a channelized warm-water stream. River 

Res. Appl. 19:289–301.

Large woody debris/weirs. Although habitat variables changed, neither species 

richness, evenness, nor fish assemblage structure differed between mitigated and 

channelized segments, with both exhibiting less richness and different assemblage 

structures than the unaltered segment. Eighty-five species.

Reeves, G. H., D. B. Hohler, et al. 1997. Fish 

habitat restoration in the Pacific Northwest: 

Fish Creek of Oregon. In J. E. Williams, C. 

A. Wood, et al. (eds.), Watershed restoration: 

Principles and practices, p. 335–359. 

American Fisheries Society, Bethesda, MD.

Large woody debris. Juvenile coho salmon were 14.8% longer for the period 

following restoration. Smolts were 6.8% longer in the same period, but not 

significant. Mean estimated annual number of young-of-the-year steelhead 

declined by 53.2% for the period following restoration. The mean for age-1 

steelhead increased 11.7% and that of smolts 27.7% following restoration, but not 

significant. Age-0 and age-1 steelhead were on average 12.5% and 4.1% larger, 

respectively, in the period after restoration.

Reich, M., J. L. Kershner, et al. 2003. Restoring 

streams with large wood: A synthesis. 

American Fisheries Society, Bethesda, MD.

Large woody debris. Synthesis of case studies. Gives project details but not 

results.

Riley, S. C., and K. D. Fausch. 1995. Trout 

population response to habitat enhancement in 

six northern Colorado streams. Can. J. Fish. 

Aquat. Sci. 52:34–53.

Large woody debris. Abundance and biomass of age-2 and older trout (and often 

age-1 trout) increased, but there was no evidence that trout were in better 

condition or grew to larger sizes. Installing 10 logs caused pool volume to 

increase from less than 40 m3 to 115–150 m3. Cover increased significantly. 

Abundance and biomass of adult trout (age-2 or older) and often juveniles (age-1)

increased significantly.

Rinne, J. N. 1982. Movement, home range, and 

growth of a rare southwestern trout in 

improved and unimproved habitats. N. Am. J. 

Fish. Manag. 2(2):150–157.

One hundred twenty-nine recaptured Gila trout moved less than 0.1 km and grew 

less in streams containing larger fish populations and in streams containing log 

improvement structures. Those that moved traveled greater distances 

downstream; less than 2% moved upstream over structures and such movement 

was limited by structures ≥0.5 m high.
97

Rodgers, J. D., S. L. Johnson, et al. 1993. The 

seasonal use of natural and constructed habitat 

by juvenile coho salmon (Oncorhynchus 

kisutch) and preliminary results from two 

habitat improvement projects on smolt 

production in Oregon coastal streams. In L. 

Berg and P. W. Delaney (eds.), Proceedings 

of the coho workshop, Nanaimo, BC, May 

26–28, 1992, p. 334–351. DFO Canada, 

Vancouver, BC.

Large woody debris/alcoves. Juvenile coho salmon. Average overwinter survival 

increased from 11% in one creek to 51% the first year, and 40% the second year 

after treatment. In another creek it increased from 14% to 63% in the first year. 

Fork length increased more in treatment reaches than in control streams.

Roni, P. 2003. Responses of benthic fishes and 

giant salamanders to placement of large 

woody debris in small Pacific Northwest 

streams. N. Am. J. Fish. Manag. 23:1087–

1097.

Large woody debris. Densities and mean lengths of giant salamanders, reticulate 

sculpins, torrent sculpins, and lampreys did not differ significantly between 

treatment and control reaches. Lamprey densities and length of age-1 and older 

reticulate sculpins among streams were positively correlated with large woody 

debris within the wetted channel. Lamprey lengths were also positively 

correlated with differences in percent of pool area.

Roni, P., T. Bennett, et al. 2006. Rehabilitation 

of bedrock stream channels: The effects of 

boulder weir placement on aquatic habitat and 

biota. River Res. Appl. 22(9):967–980.

Boulders. Pool area, number of boulders, total large woody debris (LWD) and 

LWD-forming pools were all significantly higher in treatment reaches. No 

differences in water chemistry or macroinvertebrate metrics were detected. 

Abundance of juvenile coho salmon and trout were higher in treatment reaches, 

while dace were more abundant in control reaches.
98

Roni, P., and T. P. Quinn. 2001a. Density and 

size of juvenile salmonids in response to 

placement of large woody debris in western 

Oregon and Washington streams. Can. J. 

Fish. Aquat. Sci. 58(2):282–292.

Large woody debris (LWD). Juvenile coho salmon densities were 1.8 times and 

3.2 times higher in treated reaches compared with reference reaches during 

summer and winter, respectively. Densities of age-1+ cutthroat trout and 

steelhead did not differ between treatment and reference reaches during summer,

but were 1.7 times higher in treatment reaches during winter. Total pieces of 

LWD per 100 m was significantly higher in treatment than in reference reaches 

during summer (20–80 vs. 8–63) and winter (16–78 vs. 4–64) and averaged 1.83

times and 1.89 times greater in treatment reaches in summer and winter,

respectively. The total number of functional LWD was significantly higher in 

treatment than in reference reaches during summer and winter and averaged 2.83

times and 2.96 times greater in treatment than in reference reaches. Pool area in 

treatment reaches averaged 1.52 times that in reference reaches during summer 

and 1.51 during winter, and total wetted area increased by a factor of 1.11 in 

summer and 1.08 in winter. Treated reaches had 1.31 times more pools than 

reference reaches in summer and 1.48 times more in winter. Total number of 

habitat units was 1.11 times and 1.22 times higher in treatment than in reference

reaches during summer and winter, respectively.

Roni, P., and T. P. Quinn. 2001b. Effects of 

wood placement on movements of trout and 

juvenile coho salmon in natural and artificial 

stream channels. Trans. Am. Fish. Soc.

130:675–685.

Large woody debris. Juvenile coho salmon, steelhead, and cutthroat trout. Zero 

to 33% of marked trout or coho moved between restored and reference reach. 

There were indications of considerable migration to and from the study reaches. 

In artificial channels, fewer fish moved in the woodless channel than in the

woody channel (22% vs. 37%), and the mean distance moved was shorter in the 

woody channel (4.4 vs. 6.7 habitat units). In the woodless channel, fish that 

moved grew faster than those that did not.
99

Roni, P., D. Van Slyke, et al. 2008. Adult coho 

salmon and steelhead use of boulder weirs in 

southwest Oregon streams. N. Am. J. Fish. 

Manag. 28(3):970–978.

Boulders. Coho salmon and steelhead. Number of coho spawners and peak redd 

counts were significantly higher in treatment reaches than in control reaches 

(average difference = 2.9 redds and 4.6 spawners). No differences existed in 

coho spawner counts or steelhead redd counts among reaches without weirs. 

Redd densities in tributary reaches were higher than those in mainstem reaches 

either with or without boulder weirs. Spawner density and redd density were 

positively correlated with percent gravel. Of observed redds, 43% were located 

within 10 m of a boulder weir. More than 80% of those redds were within 3 m 

upstream of a boulder weir.

Roper, B., D. Konnoff, et al. 1998. Durability 

of Pacific Northwest instream structures 

following floods. N. Am. J. Fish. Manag.

18:686–693.

Logs, boulders. Less than 20% of 3,946 structures were removed following 

floods exceeding a 5-year return interval. Less than 15% of the structures were 

moved from the site of placement in floods with return intervals less than 65 

years. Where floods exceeded a 64-year return interval, structures were almost 

two times as likely (25%) to have been removed from original placement than 

those that experienced lower intensity floods. Structures made of logs or 

boulders were more likely to have remained in place (67%) than those made of a 

combination of logs and boulders (57%). Structures were less durable in the 20% 

of the subbasins having the highest landslide frequencies.

Rosenfeld, J., D. Hogan, et al. 2011. 

Contrasting landscape influences on sediment 

supply and stream restoration priorities in 

northern Fennoscandia (Sweden and Finland) 

and coastal British Columbia. Environ. 

Manag. 47(1):28–39.

Review of restoration. No fish. Land use impacts in geologically young 

landscapes with high sediment yields vs. areas with naturally low sediment yields 

caused by low relief, resistant bedrock, and abundant mainstem lakes that trap 

sediment. Contrasting restoration priorities illustrate the consequences of 

divergent regional land use impacts on sediment supply, and the utility of 

planning restoration activities within a mechanistic sediment supply-transport 

framework. No numbers.

Rosi-Marshall, E. J., A. H. Moerke, et al. 2006. 

Ecological responses to trout habitat 

rehabilitation in a northern Michigan stream. 

Environ. Manag. 38:99–107.

Large woody debris and k-dams increased the relative abundance of harvestable 

trout (>25 cm), but not overall trout abundances. Both techniques increased 

maximum channel depth and organic matter retention, but only k-dams increased 

overall habitat quality. Macroinvertebrate density, diversity, and functional feed 

group composition were not significantly affected by the treatments. The percent 

of harvestable trout was three times higher in the skyboom reach than in the 

control reach.
100

Rubin, J. F., C. Glimsäter, et al. 2004. 

Characteristics and rehabilitation of the 

spawning habitats of the sea trout, Salmo 

trutta, in Gotland (Sweden). Fish. Manag. 

Ecol. 11:15–22.

Gravel addition. Sea trout. More than 60% of the eggs produced emerging fry in 

the artificial grounds, compared with less than 45% in the natural habitats.

Saunders, J. W., and M. W. Smith. 1962. 

Physical alteration of stream habitat to 

improve brook trout production. Trans. Am. 

Fish. Soc. 91:185–188.

Boulders, large woody debris. Brook trout. In the year following alterations, the 

standing crop of fingerlings was above average. The numbers of age-1 and older 

trout were approximately doubled. The alterations had no noticeable effect on the 

growth of trout.

Schmetterling, D. A., and R. W. Pierce. 1999. 

Success of instream habitat structures after a 

50-year flood in Gold Creek, Montana.

Restor. Ecol. 7(4):369–375.

Large woody debris and rock. Of the original 66 structures, 55 (85%) were intact 

following the flood. The mean maximum depth of remaining pools decreased 

from 1.1 m in 1996 to 0.8 m in 1997. The length of the project area occupied by 

pools increased from 452 m (13.4%) in 1996 to 958 m (17.6%) in 1997.

Sear, D. A., and M. D. Newson. 2004. The 

hydraulic impact and performance of a 

lowland rehabilitation scheme based on poolriffle installation: The River Waveney, Scole, 

Suffolk, UK. River Res. Appl. 20(7):847–

863.

Riffle/gravel. The gravel bedforms display the hydraulic functionality associated 

with natural pool-riffle sequences. At bankfull discharge, water surface elevation 

is not significantly increased over those existing prior to installation, and physical 

habitat is shown to be more diverse following rehabilitation.

Senter, A. E., and G. B. Pasternack. 2011. 

Large wood aids spawning Chinook salmon 

(Oncorhynchus tshawytscha) in marginal 

habitat on a regulated river in California.

River Res. Appl. 27(5):550–565.

Chinook salmon. Spawners built 85% of redds within one average channel width 

(31 m) of large wood. Spawners utilized large wood within a 10 m radius 36% of 

the time in the upper 3 km rehabilitated reach, and 44% of the time in the lower 

4.7 km marginal habitat reach. A greater percentage of large wood was utilized 

in riffles in the upper 3 km reach where 90% of redds were built, while a larger 

percentage of spawners used large wood in riffles in the lower 4.7 km reach. 

Large wood–redd interactions occurred at greater rates than by random chance 

alone in the lower 4.7 km reach.
101

Shetter, D. S., O. H. Clark, et al. 1949. The 

effects of deflectors in a section of a Michigan 

trout stream. Trans. Am. Fish. Soc. 76:248–

278.

Log deflectors. Brook trout. Deflectors raised the number of good pools from 9 

to 29, increased average pool depth by 6′′, and exposed additional gravel without 

significantly changing the average stream depth over the entire section. There 

was a decrease in total number and volume of all organisms, but an increase in 

forms found most frequently in trout stomachs. There were slight increases in the 

number of smaller trout present after deflector addition with a slight decrease in 

average size. Postimprovement showed an increase of 120% in the total catch 

and of 46% in pounds caught per hour with a 64% increase in angling pressure.

Shields Jr., F. D., and C. V. Alonso. 2012. 

Assessment of flow forces on large wood in 

rivers. Water Resour. Res. 48(4):W04516.

No fish. Testing flows on wood in artificial channel. For both simple and 

complex large wood, maximum lift and drag forces during the rising limb of 

unsteady flows were about 2–3 times greater than steady flow temporal mean 

values.

Shields Jr., F. D., C. M. Cooper, et al. 1993. 

Initial habitat response to incised channel 

rehabilitation. Aquat. Conserv.: Mar. Freshw. 

Ecosyst. 3(2):93–103.

Plantings and boulders. Number of fish species and mean fish length increased 

by 90% and 60%, respectively. Mean weight of fish catch increased by more 

than an order of magnitude. Weights of the largest bluegill, longear sunfish, and 

spotted bass were 18%, 572%, and 7,255% larger than their prerestoration 

counterparts, respectively. Twelve species were captured postrestoration that 

were absent prior to restoration. Wood cover increased from 38% to 66%. Mean 

depth and mean scour hole depth corrected for stage variation increased 44% and 

82%, respectively. Mean scour hole width increased 130%.

Shields Jr., F. D., S. S. Knight, et al. 1995a. 

Incised stream physical habitat restoration 

with stone weirs. Regul. Rivers: Res. Manag.

10:181–198.

Boulders. Restoration increased pool habitat availability, overall physical 

heterogeneity, riparian vegetation, shade, and woody debris density. After 

restoration, mean width, depth, and velocity exhibited changes of +56%, +150%,

and −56%, respectively, despite discharge levels that averaged 43% lower during 

data collection periods. Pool area increased to 72% of the water area. Before 

restoration, cyprinids and centrarchids comprised 74% and 11%, respectively, of 

the numerical catch, but 32% and 55% after restoration.
102

Shields Jr., F. D., S. S. Knight, et al. 1995b. 

Rehabilitation of watersheds with incising 

channels. Water Resour. Bull. 31(6):971–982.

Boulders. Depth of scour holes increased from 32 cm to 72 cm and pool habitat 

in the lower half of the study reach increased from 2.9% to 14% of water surface 

area. Median water depth at base flow increased from 9 cm to 15 cm. Woody 

vegetation cover on one side of the channel increased from 38% to 78%. Fish 

numbers tripled, median fish size increased by 50%, and the number of species 

increased from 14 to 19.

Shields Jr., F. D., S. S. Knight, et al. 1998a. 

Addition of spurs to stone toe protection for 

warm water fish habitat rehabilitation. J. Am. 

Water Resour. Assoc. 34(6):1427–1436.

Rock (stone spurs). Spur addition resulted in modest increases in base flow stony 

bankline, water width, and pool habitat availability, but only local effects on 

depth. Fish species composition shifted away from a run-dwelling assemblage 

dominated by cyprinids and immature centrarchids toward containing fewer and 

larger centrarchids. Mean water width and pool habitat availability increased by 

16% and 10%, respectively, in the treated reach following spur addition, but 

mean depth and velocity showed little change. In the immediate vicinity of the 

spurs, mean depth increased from 30 cm before toe addition to 49 cm 2 years 

later, and maximum depth increased from about 72 cm to 100 cm. Spurs 

increased the length of stable, stony shoreline in the treated reach by 24%. 

Surviving willow posts increased the fraction of sandbar margin supporting 

vegetation from 0 to 80%.

Shields Jr., F. D., S. S. Knight, et al. 1998b. 

Rehabilitation of aquatic habitats in warm

water streams damaged by channel incision in 

Mississippi. Hydrobiologia 382:63–86.

Large woody debris and stone. Species composition shifted away from small 

colonists toward larger centrarchids, catostomids, and ictalurids (50+ species). 

Fish density and species richness increased at one rehabilitated site by 72% and 

27% at its degraded reference, but remained stable at others. Pool habitat 

availability doubled. Mean depth increased 155% and velocity decreased 40%. 

Bed material became coarser. Volume of scour hole pools declined, but was still 

about 14 times greater than before rehabilitation.
103

Shields Jr., F. D., S. S. Knight, et al. 2003. 

Response of fishes and aquatic habitats to 

sand-bed stream restoration using large woody 

debris. Hydrobiologia 494:251–257.

Large woody debris and plantings. Initially, structures reduced high flow 

velocities at concave bank toes, sand berms were created, and there was a slight 

increase in base flow water width and depth. Fish assemblages were typical of 

incising streams, but minor initial responses to debris was evident. Structure 

failure and renewed erosion began during the second year after rehabilitation. 

Scour adjacent to the woody debris structures and beaver dams resulted in deeper 

(nearly two times) and slightly wider aquatic habitats and base flow relative to 

preconstruction conditions. Mean water width in the treated reached increased 

from 3 m to 5 m in 2 years. Addition of pool habitat following debris addition 

increased the fraction of numbers and biomass comprised by centrarchids in the 

treated reach from 3% to 10% and from 13% to 23%, respectively.

Shields Jr., F. D., S. S. Knight, et al. 2006. 

Large wood addition for aquatic habitat 

rehabilitation in an incised, sand-bed stream, 

Little Topashaw Creek, Mississippi. River 

Res. Appl. 22:803–817.

Large woody debris and plantings. Long-term willow survival was less than 

10%. Fish biomass increased and species richness approximately doubled. Fish 

numbers, biomass, and size increased after rehabilitation, but only biomass and 

size were statistically significant. Thirty-two species.

Shields Jr., F. D., N. Morin, et al. 2004. Large 

woody debris structures for sand-bed 

channels. J. Hydraul. Eng. 130(3):208–217.

Large woody debris. Structures reduced velocities and induced sediment 

deposition and retention. Construction costs per unit channel length were 23–

58% of costs for recent stone bank stabilization projects. Mean water depth

increased by 40–100%. Invertebrates showed a positive response to large woody 

debris both within treatment and downstream.

Shuler, S. W., R. B. Nehring, et al. 1994. Diel 

habitat selection by brown trout in the Rio 

Grande River, Colorado, after placement of 

boulder structures. N. Am. J. Fish. Manag.

14:99–111.

Boulders. On average, 65% of the adult brown trout and 69% of the juveniles 

were holding positions near structures. They used primarily wingdams, 

midchannel boulder clusters, and natural bank cover and avoided single boulders 

and areas with no structures. Eighty-nine percent of juveniles were not associated 

with structures during the day and 91% of those at night occupied positions near 

natural cover.
104

Slaney, P. A., B. O. Rublee, et al. 1994. Debris 

structure placements and whole-river 

fertilization for salmonids in a large regulated 

stream in British Columbia. Bull. Mar. Sci.

55:1160–1180.

Large woody debris and fertilization. Juvenile Chinook salmon highly colonized 

stream-side debris structures. Fry density was similar to that in natural woody 

cover. Adult rainbow trout also more extensively colonized debris structures than 

nonstructure sites.

Smokorowski, K. E., and T. C. Pratt. 2007. 

Effect of a change in physical structure and 

cover on fish and fish habitat in freshwater 

ecosystems—a review and meta-analysis.

Environ. Rev. 15:15–41.

Meta-analysis of many studies. On the whole, decreases in structural habitat 

complexity are detrimental to fish diversity and can change species composition. 

Increases in structural complexity showed increases, decreases, or no measurable 

changes in species or communities. The majority of the meta-analysis resulted in 

supporting a direct link between habitat and fish abundance and biomass, with 

fish biomass responding most strongly to habitat change.

Solazzi, M. F., T. E. Nickelson, et al. 2000. 

Effects of increasing winter rearing habitat on 

abundance of salmonids in two coastal Oregon 

streams. Can. J. Fish. Aquat. Sci. 57:906–

914.

Large woody debris. Average winter rearing habitat increased 13 times over that 

in the previous year, while the reference area stayed the same. Fast water habitat 

in the treatment stream decreased by about 6,000 m2 but remained relatively 

constant in the reference stream. Mean summer population of juvenile coho 

salmon increased by 50%, while there was a 25% decrease in the reference

stream. Mean number of coho smolts increased by more than 200%, while the 

reference stream stayed the same. Mean number of coho migrants doubled, but 

decreased 75% in the reference stream. Overwinter survival of coho salmon

increased from a mean of .13 to .38 (reference was .17 to .20). In another stream, 

mean overwinter survival increased 250% from .11 to .39, but fell in the reference

stream from .19 to .10. Mean number of steelhead migrants increased by more 

than 800%. Cutthroat trout migrants in the treatment stream increased by 275% 

and decreased 75% in the reference stream.

Spanhoff, B., W. Riss, et al. 2006. Effects of an 

experimental enrichment of instream habitat 

heterogeneity on the streambed morphology 

and chironomid community of a straightened 

section in a sandy lowland stream. Environ. 

Manag. 37(2):247–257.

Large woody debris effects on invertebrates. No good numbers. Diversity in the 

wood-enriched section was distinctly lower compared to the control section the 

first year, but nearly equal in the second sampling period.
105

Stewart, G. B., H. R. Bayliss, et al. 2009. 

Effectiveness of engineered instream structure 

mitigation measures to increase salmonid 

abundance: A systematic review. Ecol. Appl.

19(4):931–941.

Review of 17 studies. Meta-analysis shows that evidence regarding the 

effectiveness of instream devices is equivocal. Heterogeneity is significant both 

for population size and local habitat preference. Heterogeneity is related to 

stream width, with instream devices being less effective in larger streams. 

Engineered structures show no detectable effect on local abundance, indicating no 

habitat preference. No numbers. Many species.

Sudduth, E. B., and J. L. Meyer. 2006. Effects 

of bioengineered streambank stabilization on 

bank habitat and macroinvertebrates in urban 

streams. Environ. Manag. 38(2):218–226.

Amount of wood and root bank habitat was much higher at the reference site and 

three of four bioengineered sites than at the unrestored site or the fourth 

bioengineered site. Higher biomass and abundance were found on organic 

habitats vs. inorganic habitats across all sites. Percent organic bank habitat 

proved to be strongly positively correlated with invertebrate taxon richness, total 

biomass, and shredder biomass.

Sundermann, A., S. Stoll, et al. 2011. River 

restoration success depends on the species 

pool of the immediate surroundings. Ecol. 

Appl. 21(6):1962–1971.

No fish. Analyzed 24 restoration projects. On average, the restorations did not 

improve the benthic invertebrate community quality. Restoration success 

depends on the presence of source populations of desired taxa in the surrounding 

of restored sites. Only where source populations of additional desired taxa 

existed within a 0–5 km ring around the restored sites were invertebrate

assemblages improved by the restoration. Beyond the 5 km rings, the 

recolonization effect was no longer detected.

Tarzwell, C. M. 1937. Experimental evidence 

on the value of trout stream improvement in 

Michigan. Trans. Am. Fish. Soc. 66:177–187.

Large woody debris structures. Each deflector produced on average 82 sq. ft. of 

plant bed, 392 sq. ft. of mucky area, 965 sq. ft. of riffle, and uncovered 144 sq. ft. 

of graveled area. Improved bottom average was 2,027 sq. ft. in one river and 

1,418 in another. More legal trout were taken and the average size of the trout 

was greater after improvement. Before improvement, 71 legal trout were caught 

in 75.75 hours. After improvement, 250 were caught in 167.5 hours. The counts 

of organisms per unit area was 3–5 times greater after improvements than before. 

In the riffle areas produced by the barriers, 4.53 times as much food was found as 

before improvements.
106

Tarzwell, C. M. 1938. An evaluation of the 

methods and results of stream improvement 

in the Southwest. Trans. Third North Am. 

Wildl. Conf. 1938:339–364.

Large woody debris structures. Rainbow trout, brook trout, brown trout, and 

Yellowstone native trout. Creel census showed 25,150 fish caught in the 

treatment over 6 years and 46,190 in the control, but almost twice as many trout 

were placed in the control. The yield in pounds per acre from the treatment creek 

was greater than from the control reach by 8.6 lb in 1 year, and by 16.6 lb in 

another. Riffles are richer than the natural pools, but the artificial pools in the 

treatment creek are richer than the riffles due to the collection of debris and 

organic materials in them. The control creek yielded 1 lb of trout to 4.97 lb of 

bottom organisms and the treatment creek had 1 lb of trout to 5.48 lb of bottom 

organisms.

Thom, B. A. 1997. The effects of woody debris 

additions on the physical habitat of salmonids: 

A case study on the northern Oregon coast. 

Master’s thesis. Univ. Washington, Seattle.

Examined physical effects of large woody debris placement in nine streams with 

paired treatment and reference reaches using a before-after control-impact design. 

Positive treatment effects were observed for various large woody debris and 

habitat metrics (number of pieces, jams, habitat units, number of pools, slack

water pools). Treatment reaches increased from 11.7 to 17.2 pieces of wood and 

from 21.1 to 25.1 m3 of wood per 100 m. Key pieces increased on average 0.8 

pieces per 100 m and decreased in control reaches 0.50 pieces per 100 m. 

Proportion of slack water pools (alcoves, backwaters, dammed pools, etc.) in 

treatment reaches after treatment increased fourfold in summer and sevenfold in 

winter.

Thompson, D. M. 2002. Long-term effect of 

instream habitat-improvement structures on 

channel morphology along the Blackledge and 

Salmon rivers, Connecticut, USA. Environ. 

Manag. 29(2):250–265.

Large woody debris. Cover structures have produced a 30% reduction in 

streamside vegetation with over 75% less overhead cover than unaltered reaches.

Thompson, D. M. 2006. Did the pre-1980 use 

of instream structures improve streams? A 

reanalysis of historical data. Ecol. Appl.

16(2):784–796.

Review of 79 publications. Little evidence of the successful use of instream 

structures to improve fish populations exists prior to 1980.
107

Tikkanen, P., P. Laasonen, et al. 1994. Shortterm recovery of benthos following 

disturbance from stream habitat rehabilitation.

Hydrobiologia 270(2):121–130.

Boulders. The immediate effect of rehabilitation was a slight decrease in the 

abundances of benthic insects and recolonization occurred rapidly (within 10 

days). Disturbance of the rehabilitation work did not have a detectable effect on 

the invertebrate community. The detection of effects was obscured by rapid life 

cycle phenomena taking place at the same time.

Van Zyll De Jong, M. C., I. G. Cowx, et al. 

1997. An evaluation of instream habitat 

restoration techniques on salmonid 

populations in a Newfoundland stream.

Regul. Rivers: Res. Manag. 13:603–614.

Boulders/logs. Boulder clusters were the most effective structure, increasing 

densities of 0+, 1+ and 3+ juvenile Atlantic salmon. V dams were effective in 

increasing the density of both brook trout and Atlantic salmon through creation of 

more diverse pool habitat. Half-log covers increased the number of juvenile 

salmon age 0+ through an increase in instream cover. Boulder sites were the 

shallowest, fastest flowing reaches and boulders substantially increased the large 

substrate composition. Boulder clusters increased habitat diversity.

Vehanen, T., A. Huusko, et al. 2003. Habitat 

preference by grayling (Thymallus thymallus) 

in an artificially modified, hydropeaking 

riverbed: A contribution to understand the 

effectiveness of habitat enhancement 

measures. J. Appl. Ichthyol. 19(1):15–20.

Boulders. Grayling largely stayed in the restored area and avoided the unchanged 

channel. The range of daily movement was from stationary to 2,700 m per day. 

Adult grayling preferred water velocities between 0.20 and 0.45 m/s−1, depths 

between .20 and 1.55 m, and coarse substrate.

Vehanen, T., A. Huusko, et al. 2010. Effects of 

habitat rehabilitation on brown trout (Salmo 

trutta) in boreal forest streams. Freshw. Biol.

55(10):2200–2214.

Brown trout. Treatments were large woody debris with boulders, boulders alone, 

and unmodified. Restoration increased streambed complexity but did not have a 

detectable effect on brown trout stocks for large woody debris or boulders except 

for age-2 and older fish, which decreased in abundance compared to control 

reaches. Structures provided some safeguard against drought for age-2 and older 

fish, but not for the younger age-classes.
108

Viola, A. E., M. L. Schuck, et al. 1991. An 

evaluation of instream habitat alterations in 

southeast Washington, 1983–1989. Fisheries 

Management Division Series: FM 91-11. 

Washington Dept. Wildlife, Olympia.

Large woody debris. There was a significant increase in the density and biomass 

of older aged wild rainbow trout/steelhead. Altered streams had wild 

rainbow/steelhead biomass increase from 37.7 g/100 m2 to 1508.3 g/100 m2

5 years postconstruction. Biomass in the control reaches was 52.2 g/100 m2

preconstruction and 605.2 g/100 m2 postconstruction. The instream habitat 

structures concentrated hatchery fish and provided increased harvest within

habitat-altered river sections, created aesthetically pleasing areas for anglers, and 

increased spawning use by steelhead and Chinook salmon.

Violin, C. R., P. Cada, et al. 2011. Effects of 

urbanization and urban stream restoration on 

the physical and biological structure of stream 

ecosystems. Ecol. Appl. 21(6):1932–1949.

No fish. Compared physical and biological structure of four urban degraded, four

urban restored, and four forested sites. Restored streams were indistinguishable 

from their degraded urban counterparts. Forested streams were shallower, had 

greater habitat complexity and median sediment size, and contained less-tolerant 

invertebrate communities with higher sensitive taxa richness than streams in 

either urban category. Restored streams had less canopy cover. Channel habitat 

complexity and watershed impervious surface cover were the best predictors of 

sensitive taxa richness and biotic index at the reach and catchment scale, 

respectively. Invertebrate communities in restored channels were 

compositionally similar to those in urban degraded channels and both were 

dissimilar to communities in forested streams. Reach-scale restoration is not 

successfully mitigating for factors causing physical and biological degradation.

Wallace, J. B., J. R. Webster, et al. 1995. 

Influence of log additions on physical and 

biotic characteristics of a mountain stream.

Can. J. Fish. Aquat. Sci. 52:2120–2137.

Large woody debris. Sampled upstream of debris dams. Stream depth increased 

(20–30 cm), current velocity decreased, cobble was covered by sand and silt, and 

both coarse and fine particulate organic matter increased dramatically. 

Abundances and biomass of scrapers and filterers decreased; collectors and 

predators increased. Secondary production of scrapers and filterers decreased, 

whereas that of collectors and predators increased.
109

Ward, B. R., and P. A. Slaney. 1981. Further 

evaluations of structures for the improvement 

of salmonid rearing habitat in coastal streams 

of British Columbia. In T. J. Hassler (ed.), 

Proceedings: Propagation, Enhancement, and 

Rehabilitation of Anadromous Salmonid 

Populations and Habitat in the Pacific 

Northwest Symposium, p. 99–108. Humboldt 

State Univ., Arcata, CA.

Large woody debris and boulders. The mean number of steelhead parr and coho 

salmon fry in boulder groupings increased to 0.10 m2 and 0.27 m2, respectively. 

Groupings ranked highest in salmonid standing crop. Gabions failed to increase 

steelhead parr abundance, but significantly increased juvenile coho salmon. 

Steelhead significantly increased by around one parr per boulder. There was a 

400% increase in number of steelhead parr/lineal m in the boulder clusters.

Warner, K., and I. R. Porter. 1960. 

Experimental improvement of a bulldozed 

trout stream in northern Maine. Trans. Am. 

Fish. Soc. 89(1):59–63.

Boulder structures. Sixty-three deflectors had successfully narrowed the flow or 

created pools. Rock dams were largely unsuccessful. After 2 years, 37 deflectors 

were virtually unaffected by freshets. Spring holes created pools 6–30′′ deep. 

Young-of-the-year trout were moderately abundant where few had been seen 

previously.

Weber, C., and A. Peter. 2011. Success or 

failure? Do indicator selection and reference 

setting influence river rehabilitation outcome?

N. Am. J. Fish. Manag. 31(3):535–547.

No specific fish. In 32 (80%) of the 40 studies, fish response was measured at the 

population level. Structural and compositional indicators dominated (31 and 24 

studies, respectively), while functional indicators were underrepresented (five

studies). Eighteen studies used multiple indicator types for a given ecosystem 

attribute, a given hierarchical level, or both. Among these studies, they found 

only very limited evidence that project outcome differed among different 

indicator types (one study). In contrast, highly heterogeneous results were found 

within the different indicator types at the level of the individual study. Such 

heterogeneity was related to the spatiotemporal variability of the results and 

species-specific responses to physical habitat rehabilitation. Most studies (73%,

29 studies) used a single type of reference and the majority focused on degraded 

conditions. Among the 10 studies that applied multiple reference types, three

studies showed inconsistent results.
110

West, J. P. 1984. Enhancement of salmon and 

steelhead spawning and rearing conditions in 

the Scott and Salmon rivers, California. 

In T. J. Hassler (ed.), Proceedings: Pacific 

Northwest Stream Habitat Management 

Workshop, p. 117–127. Humboldt State 

Univ., Arcata, CA.

Chinook salmon, steelhead. Fine sediment was reduced about 18%. Use of 

treated areas rose from no use to approximately 29 redds/season. After boulder 

placement, steelhead juvenile rearing increased tenfold. Salmon and steelhead 

spawner use increased threefold. Use of control area was relatively static.

Wheaton, J. M., G. B. Pasternack, et al. 2004. 

Use of habitat heterogeneity in salmonid 

spawning habitat rehabilitation. In D. Garcia 

de Jalon Lastra and P. Vizcano Martinez 

(eds.), Fifth International Symposium on 

Ecohydraulics, Aquatic Habitats: Analysis & 

Restoration, p. 791–796. Madrid, Spain.

Chinook salmon. Hydrodynamic shear zones provide equally important refuge 

from predation and resting zones for energy conservation. The increased 

heterogeneity appeared highly effective in terms of redd utilization, with 70 redds 

located in close proximity to 93% of the available structural cover and 42 redds 

located in close proximity to 90% of the available shear zone refugia.

White, S. L., C. Gowan, et al. 2011. Response 

of trout populations in five Colorado streams 

two decades after habitat manipulation.

Can. J. Fish. Aquat. Sci. 68(12):2057–2063.

Log weirs. Brook trout. Pool volume remained more than three times higher in 

treatment sections and mean depth was also greater. Adult trout abundance 

increased rapidly after installation and remained 53% higher in treatment sections 

than in controls 21 years later. Effects on juvenile trout were not detected. Of 53 

logs installed, all were in place 21 years later and 98% were functioning to create 

dammed and plunge pools. Pool volume averaged 229% higher in treatment 

sections in 2009; treatment sections had an average of 54% more adult trout in 

2009.

Whiteway, S. L., P. M. Biron, et al. 2010. Do 

instream restoration structures enhance 

salmonid abundance? A meta-analysis.

Can. J. Fish. Aquat. Sci. 67(5):831–841.

Analysis of 211 projects using instream structures. Seven species. Showed 

significant increase in pool area (mean effect size = .65), average depth (mean 

effect = .29), large woody debris (mean effect size = .73), and percent cover 

(mean effect size = 1.14), as well as a decrease in riffle area (mean effect size = 

−52). There was a significant increase in salmonid density (mean effect size of 

.51 or 167%) and biomass (mean effect size of .48 or 162%). Large differences 

were observed between species, with rainbow trout showing the largest increases 

in density and biomass. Projects with multiple structures increased pool area 

more than those with only one type of structure.
111

Wilkins, L. P. 1960. Construction and 

evaluation of stream alteration structures. 

Project F-6-R. Tennessee Game and Fish 

Commission, Nashville.

Logs and boulders. Wild rainbow trout populations declined in the 2 years after 

construction, but this was associated with an increase in anglers. A significant 

increase in young-of-the-year trout occurred, while the standing crop of agegroup-1 trout has gradually increased despite greater fishing intensity.

Yrjana, T. 1998. Efforts for instream fish 

habitat restoration within the River Iijoki 

Finland—goals, methods, and test results. 

In L. C. De Waal, A. R. G. Large, et al. (eds.), 

Rehabilitation of rivers: Principles and 

implementation, p. 239–250. Wiley & Sons 

Ltd., Chelsea, UK.

Boulders and gravel. No good numbers. Restoration was immediately followed 

by a decrease in the number of benthic fauna, but it returned to prior levels within 

2 weeks. The biomass and density of trout yearlings was significantly greater in 

the restored areas. Boulder groups should be placed on spawning grounds to 

offer cover and increase local velocities.

Zika, U., and A. Peter. 2002. The introduction 

of woody debris into a channelized stream:

Effect on trout populations and habitat. River 

Res. Appl. 18(4):355–366.

Large woody debris. Brown trout and rainbow trout. No good numbers. 

Abundance and biomass of brown and rainbow increased. Maximum and 

standard deviation of fish total length increased in all sections during summer. 

The number of individuals and standard deviations of total lengths decreased in 

the control section in winter, but increased in the treatment section. Mean water 

velocities decreased and number and volume of pools increased in the treatment 

section. Trout sought woody debris for cover.

Off-Channel/Floodplain Habitat References (Subtotal is 82 of 409)

Reference Key Quantitative Findings

Akita, M., Y. Makiguchi, et al. 2006. Upstream 

migration of chum salmon through a restored 

segment of the Shibetsu River. Ecol. Freshw. 

Fish 15:125–130.

Remeander. Radiotagged chum salmon held in deep, slow current near bottom 

near the banks in the canalized river. In the restored area, chum swam in more 

shallow areas against stronger currents.

Albert, S., and T. Trimble. 2000. Beavers are 

partners in riparian restoration on the Zuni 

Indian reservation. Ecol. Restor. 18(2):87–92.

Beaver reintroduction. With new dams, water flow slowed, streambed raised, 

hydrology improved, salt cedar infestation reduced, and willows increased. 

Problems were farmland flooding and destruction of many large trees.
112

Apple, L. L. 1985. Riparian habitat restoration 

and beavers. In R. R. Johnson, C. D. Ziebell, 

et al. (eds.), Riparian ecosystems and their 

management: Reconciling conflicting uses, 

p. 489–490. Gen. Tech. Rep. RM-120. U.S. 

Forest Service, Rocky Mountain Forest and 

Range Experimental Station, Fort Collins, CO.

No concrete numbers. Beavers built three major dam complexes that developed 

subirrigated meadow areas. Mud bars formed behind the dams, water tables were 

elevated, and full riparian recovery was underway.

Baattrup-Pedersen, A., T. Riis, et al. 2000. 

Restoration of a Danish headwater stream: 

Short-term changes in plant species abundance 

and composition. Aquat. Conserv.: Mar. 

Freshw. Ecosyst. 10(1):13–23.

Effects of stream restoration (remeandering) on plant communities. Number of 

species decreased 25% in the stream and 9% on the banks, increased 15% in the 

stream valley. On the bank, dominance changed from nonriparian species to 

more diverse communities. Little change to plant communities in the valley.

Biggs, J., A. Corfield, et al. 1998. Restoration 

of the rivers Brede, Cole and Skerne: A joint 

Danish and British EU-LIFE demonstration 

project, V: Short-term impacts on the 

conservation value of aquatic 

macroinvertebrate and macrophyte 

assemblages. Aquat. Conserv.: Mar. Freshw. 

Ecosyst. 8(1):241–255.

No fish. Invertebrates and aquatic vegetation Wetland macrophyte species 

richness quickly reached prerestoration levels relative to control sections. 

Emergent plant species richness remained the same or increased after restoration. 

One year after restoration, the mean emergent plant species richness increased 

from 27 to 38 species/500 m survey length. There was a highly significant 

increase in species richness between years, but no interaction between location 

and year. Number of aquatic plant species went from 7.5 species prerestoration 

to 7.0 species within a month of restoration and 8.0 species 1 year postrestoration. 

The abundance of invertebrates generally recovered less rapidly than species 

richness. Downstream of the restored area showed a relative decline in 

invertebrate species richness 1–2 months after restoration.

Blackwell, C. N., C. R. Picard, et al. 1999. 

Smolt productivity of off-channel habitat in 

the Chilliwack River watershed. Rep. 14. 

Watershed Restoration Program, Ministry of 

Environment, Lands, and Parks and Ministry 

of Forests, Vancouver, BC.

Four restored and three natural off-channel habitats monitored during smolt 

migration. No difference in coho salmon smolt production from natural vs. 

restored habitats. Major benefits will be quantity, not quality of available habitat. 

Juvenile steelhead utilized off-channel areas in low densities (<1 smolt/100 m2). 

Coho smolt abundance varied from less than 2/100 m2 to greater than 50/100 m2

.
113

Boedeltje, G., A. J. P. Smolders, et al. 2001. 

Constructed shallow zones along navigation 

canals: Vegetation establishment and change 

in relation to habitat characteristics. Aquat. 

Conserv.: Mar. Freshw. Ecosyst. 11:453–471.

Constructed shallow side channels and studied vegetation Although submerged 

aquatic macrophytes persist for a relatively short time, shallow zones function as 

habitat for helophyte communities and contribute to a higher aquatic biodiversity.

Bryant, M. D. 1988. Gravel pit ponds as habitat 

enhancement for juvenile coho salmon. 

PNW-GTR-212. U.S. Forest Service, Pacific 

Northwest Research Station, Portland, OR.

No numbers. Gravel pits flooded and connected to rivers. The ponds were found 

to support coho salmon throughout the winter. Number of coho fluctuated, but 

was high (2,000 coho) throughout study. Coho in the less productive ponds 

appeared to be less robust than those in the other two ponds.

Carl, J. 2001. Habitat surveys as a tool to assess 

the benefits of stream rehabilitation 3: Fish. 

Int. Assoc. Theor. Appl. Limnol. Proc.

(27):1515–1519.

Abundance results indicate restoration measures (remeandering and 

discontinuance of stream maintenance) can improve the overall stream 

environment and increase total abundance of trout, but it is not clear what habitat 

types are beneficial to improving abundance.

Caruso, B. S. 2006. Effectiveness of braided, 

gravel bed river restoration in the Upper 

Waitaki Basin, New Zealand. River Res. 

Appl. 22(8):905–922.

Evaluates the effectiveness of a river recovery project. No numbers. Lists 

recommended elements and restoration components with no specifics.

Cederholm, C. J., and N. P. Peterson. 1989. A 

summary comparison of two types of winter 

habitat enhancement for juvenile coho salmon 

(Oncorhynchus kisutch) in the Clearwater 

River, Washington. In B. G. Shepherd (ed.), 

Proceedings of the 1988 Northeast Pacific 

Chinook and Coho Salmon Workshop, 

p. 227–239. Ministry of Environment, 

Penticton, BC.

Constructed pond: winter coho salmon survival rate increased from .11 to .56, 

mean length increased from 13 to 41mm, and mean weight increased from 3 to 

13 g. Constructed braided channel: significant increase in winter survival (rate = 

.57) and growth (postconstruction 20 mm length and 5.6 g weight—no 

preconstruction data).

Cederholm, C. J., W. J. Scarlett, et al. 1988. 

Low-cost enhancement technique for winter 

habitat of juvenile coho salmon. N. Am. J. 

Fish. Manag. 8:438–441.

Constructed habitat. Overwinter survival and growth of coho salmon increased 

significantly after construction (survival .11 to .56, mean change in length from 

13 to 41 mm, mean change in weight from 3 to 13 g).
114

Childers, D. L., D. M. Iwaniec, et al. 1999. 

How freshwater Everglades wetlands mediate 

the quality of recently enhanced water inflows 

to the Florida Bay estuary. Gulf Res. Rep. 

11:70–71.

Abstract only (Gulf Estuarine Research Society meeting). No fish. Nutrient 

concentrations more than doubled immediately after levee removal, from about 

0.2 to 0.4 μM [micromolar?] total phosphorus and from about 45 to 140 μM total 

nitrogen. However, the sawgrass marsh quickly took up this nutrient load. Flume 

sampling showed ammonium and dissolved organic carbon uptake, and total 

organic carbon release. The periphyton zone imported total nitrogen, while 

nitrate-nitrite flux was dominated by marsh dynamics.

Childers, D. L., N. J. Oehm, et al. 1998. How 

freshwater Everglades wetlands mediate 

changes in water flow and nutrient loadings 

to the Florida Bay estuary. Gulf Res. Rep. 

10:72.

Abstract only (Gulf Estuarine Research Society meeting). See Childers et al. 

1999 above.

Chovanec, A., F. Schiemer, et al. 2002. 

Rehabilitation of a heavily modified river 

section of the Danube in Vienna (Austria): 

Biological assessment of landscape linkages 

on different scales. Int. Rev. Hydrobiol.

87:2–3.

Levee removal—fish species richness increased with connectivity. No numbers. 

Colonization of structures by dragonflies (28 species). Amphibians: 12 out of 20 

potential species colonized island.

Clarke, S. J., and G. Wharton. 2000. An 

investigation of marginal habitat and 

macrophyte community enhancement on the 

River Torne, UK. Regul. Rivers: Res. Manag.

16:225–244.

Evaluated marginal habitat and macrophyte community 5 years after bank 

reprofiling and planting program. Enhanced reaches were floristically distinct 

and had higher values of wetland species diversity, percent of wetland species, 

bank width, soil moisture, and lower bank angles.

Clayton, S. R. 2002. Quantitative evaluation of 

physical and biological responses to stream 

restoration. Doctoral dissertation. Univ. 

Idaho, Moscow.

Remeander. Following restoration, reach-median maximum depths at base flow 

increased 56% to 0.43 m and velocities decreased 24% to 0.28 m/s. At bankfull 

discharge, reach-median maximum depths increased 30% to 1.5 m and velocities 

decreased 17% to 0.85 m/s. Pool frequency increased by 50%, resulting in an 

even pool:riffle ratio.
115

Cooperman, S., G. Hinch, et al. 2006. Rapid 

assessment of the effectiveness of engineered 

off-channel habitats in the southern interior of 

British Columbia for coho salmon production. 

Rep. 2768. DFO Canada, Vancouver, BC.

Coho salmon. Ten studies, not a lot of numbers. Eight of 10 off-channel projects 

appear to be functioning as designed, although five of those have conditions that 

could compromise their utility to young coho (beaver dams or extensive aquatic 

macrophyte growth to limit connectivity to parent system or impair water 

quality). Effectiveness would improve by providing upwelling groundwater and 

by routine project maintenance.

Cott, P. A. 2004. Northern pike (Esox lucius) 

habitat enhancement in the Northwest 

Territories. DFO Canada, Yellowknife, 

Northwest Territories. Can. Tech. Rep. Fish. 

Aquat. Sci. 2528.

Constructed ponds and channels connected to river. Yielded successful spawning 

and utilization of nursery habitat by northern pike. Spottail shiners and 

invertebrates used the new area as well. Area revegetated itself. Ultimate habitat 

gain was calculated to be more than 11:1.

Cowx, I. G., and M. Van Zyll de Jong 2004. 

Rehabilitation of freshwater fisheries: Tales 

of the unexpected? Fish. Manag. Ecol. 11(3–

4):243–249.

Case study 1: Boulder treatments caused significant +0 and +1 salmon density 

increase, V-dam treatment significantly increased +0 salmon in second posttreatment year, half-log cover increased +0 salmon density for both posttreatment years. Trout densities did not change significantly for any age-class. 

Case study 2: Remeander and creation of pool and riffle habitat—upper reaches 

had reasonably good brown trout populations reaching 46 per 100 m−2

, middle 

and lower reaches had low density of absence of mixed coarse fish assemblage or 

had an impoverished coarse fish community. In general, there was a weak 

response of the fish populations to the improvement measures.

Decker, A. S., and M. J. Lightly 2004. The 

contribution of constructed side channels to 

coho salmon smolt production in the Oyster 

River, Nanaimo, BC, Canada. Can. Tech. 

Rep. Fish. Aquat. Sci. 40.

Constructed three side channels. Mean density of outmigrating coho salmon 

smolts was 2.3 times greater in the side channels than in the main stem (4,857 vs. 

2,117 smolts km−1

). Smolt outmigrants from side channels represented 13% 

(±1.3%) of the estimated total smolt production for the river, though only 6% of 

the total habitat by stream length.

Florsheim, J. L., and J. F. Mount. 2002. 

Restoration of floodplain topography by sandsplay complex formation in response to 

intentional levee breaches, Lower Cosumnes 

River, California. Geomorphology 44(1–2):

67–94.

Levees breached and subsequent study of sand-splay complexes. Rapid vertical 

accretion and scour occurred. Maximum deposition measured on the splay 

surface was 0.36 m/year and maximum scour in channels was 0.27 m/year.
116

Friberg, N., B. Kronvang, et al. 1998. Longterm, habitat-specific response of a 

macroinvertebrate community to river 

restoration. Aquat. Conserv.: Mar. Freshw. 

Ecosyst. 8(1):87–99.

Remeandering. Created a physically stable environment in less than 3 years with 

an improved density and diversity of macroinvertebrates.

Grift, R. E. 2001. How fish benefit from 

floodplain restoration along the lower River 

Rhine. Wageningen Univ., Institute of 

Animal Sciences, Wageningen, The 

Netherlands.

Reconnection of off-channel habitats. Presence and abundance of rheophilic 

cyprinids increased from isolated oxbow lake to connected oxbow lake and 

secondary channels. Water flow and connectivity are important factors driving 

the structure of the young-of-the-year fish community. Secondary channels 

provide suitable nursery habitat for rheophilic cyprinids.

Grift, R. E., A. D. Buijse, et al. 2001. 

Restoration of the river-floodplain interaction: 

Benefits for the community in the River 

Rhine. Arch. Hydrobiol. Large Rivers 12(2–

4):173–185.

Constructed side channels had a beneficial value for the riverine fish community. 

They serve as nursery areas for all rheophilic cyprinids and spawning areas for a 

couple of those species.

Grift, R. E., A. D. Buijse, et al. 2003. Suitable 

habitats for 0-group fish in rehabilitated 

floodplains along the lower River Rhine. 

River Res. Appl. 19(4):353–374.

Constructed side channels. Total fish density increased along a gradient of 

decreasing water flow, whereas the proportion of rheophilic species decreased. 

Flow velocity and water depth were most important factors determining habitat 

utilization. During floods, inundated terrestrial vegetation was important habitat 

for the larvae of all species. Floodplain water bodies should have complex 

shorelines and a high variability of flow velocities.

Habersack, H., and H. P. Nachtnebel. 1995. 

Short-term effects of local river restoration on 

morphology, flow field, substrate, and biota. 

Regul. Rivers: Res. Manag. 10:291–301.

Constructed side channel. Study showed higher growth of algae, higher numbers

of species of macroinvertebrates, and greater densities of fish species.

Hammersmark, C. T., M. C. Rains, et al. 2008. 

Quantifying the hydrological effects of stream 

restoration in a montane meadow, northern 

California, USA. River Res. Appl. 24(6):735–

753.

No fish. Model simulations yielded three general hydrological responses to the 

meadow restoration effort: 1) increased groundwater levels and volume of 

subsurface storage, 2) increased frequency/duration of floodplain inundation and 

decreased magnitude of flood peaks, and 3) decreased annual runoff and duration 

of base flow. “Pond and plug” type stream restoration has the capacity to 

reestablish hydrological processes necessary to sustain riparian systems.
117

Hansen, H. O. 1998. Stream restoration: 

Rehabilitation of a headwater stream and its 

riparian areas—Layman Report. Final 

Layman report from the EU-LIFE project. 

Ministry of Environment and Energy, 

National Environmental Research Institute, 

Silkeborg, Denmark.

Remeander, raised stream water level, added coarse substrate for spawning. At 2 

years post-treatment, only terrestrial plants had recovered. Fish and invertebrates

had not reached expected levels, however, the number of brown trout caught posttreatment approached expected levels. No numbers.

Hein, T., C. Baranyi, et al. 1999. Hydrology as 

a major factor determining plankton 

development in two floodplain segments and 

the River Danube, Austria. Arch. Hydrobiol. 

Large Rivers 11:439–452.

Reconnection. No numbers. Lotic conditions led to higher phytoplankton 

biomass. Heterotrophic compartments dominated plankton under lentic 

conditions. The biomass ratio of phyto-to-bacterioplankton declined as 

hydrological connectivity decreased.

Henning, J. A., R. E. Gresswell, et al. 2006. 

Juvenile salmonid use of freshwater emergent 

wetlands in the floodplain and its implications 

for conservation management. N. Am. J. Fish. 

Manag. 26:367–376.

Reconnection. Added water control structures to emergent wetlands to provide 

an outlet for fish emigration. Resulted in higher abundance of age-1 coho salmon

in enhanced wetlands. Yearling coho had comparable specific growth rate and 

minimum estimates of survival (1.43%/d by weight and 30%, 1.37%/d and 57%) 

to other side channel–rearing studies.

Hoffmann, C. C., M. L. Pedersen, et al. 1998. 

Restoration of the rivers Brede, Cole and 

Skerne: A joint Danish and British EU-LIFE

demonstration project, IV–Implications for 

nitrate and iron transformation. Aquat. 

Conserv.: Mar. Freshw. Ecosyst. 8(1):223–

240.

Remeander. Ninety-two kg NO3-N ha−1 year−1 of nitrate was removed during 

passage through the river valley. Iron leaked from the floodplain to the river at

400 kg ha−1 year−1. There was higher removal of nitrate along the restored reach 

during a 3-month period of flooding right after restoration.

Holubova, K., and M. J. Lisicky. 2001. River 

and environmental processes in the wetland 

restoration of the Morava river. In R. A. 

Falconer and W. R. Blain, River basin 

management, p. 179–180. WIT, 

Southampton, UK.

Meander reconnection. Abundance of limnophilous fish species lowered in favor 

of both reophilous and eurytopic species, but the number of species did not 

change. Species diversity of water macrophytes decreased from 13 to five. 

Invertebrates showed a shift from stagnicolous to semireophilous species 

composition. A large gravel-sand bank formed, creating a new habitat used in the 

first year by terrestrial annual plants.
118

Iversen, T. M., B. Kronvang, et al. 1993. Reestablishment of Danish streams: Restoration 

and maintenance measures. Aquat. Conserv.: 

Mar. Freshw. Ecosyst. 3(2):73–92.

Remeander. Invertebrates increased to 75 species in restored reached compared 

with 62 in control reach. Harmful effects of the project on downstream reaches 

was negligible and a stable abiotic and biotic stream environment was established 

within 2 years.

Jähnig, S. C., S. Brunzel, et al. 2009. Effects of 

re-braiding measures on hydromorphology, 

floodplain vegetation, ground beetles, and 

benthic invertebrates in mountain rivers. 

J. Appl. Ecol. 46:406–416.

Rebraiding. Number of floodplain mesohabitats was significantly higher in 

restored sections, but there was no significant effect on the number of aquatic 

microhabitats. Mean length of mesohabitats increased by a factor of 3 to 0 

(terrestrial) 1 to 4 (aquatic) and 5 to 9 (transient parts). Plants: the median species 

richness was 60 in the nonrestored and 125 in the restored sections. Median 

number of genera increased from 62 to 86 and median number of families from 

28 to 35. Ground beetles: proportion of riparian species was 75•2% in the 

restored sections and 29•5% in nonrestored sections. 169 benthic invertebrate

taxa were recorded. Values of metrics were always slightly higher in restored 

sections.

Jeffres, C. A., J. J. Opperman, et al. 2008. 

Ephemeral floodplain habitats provide best 

growth conditions for juvenile Chinook 

salmon in a California river. Environ. Biol. 

Fishes 83(4):449–458.

Juvenile Chinook salmon. There were significant differences in growth rates 

between salmon rearing in floodplain and river sites. Salmon reared in seasonally 

inundated habitats with annual terrestrial vegetation showed higher growth rates 

than those reared in a perennial pond on the floodplain. Growth of fish in the 

river upstream of the floodplain varied with flow and turbidity. When flows and 

turbidity were high, there was little growth and high mortality, but when flows 

were low and clear, the fish grew rapidly. Fish in tidal river habitat below the 

floodplain showed very poor growth rates. Ephemeral floodplain habitats 

supported higher growth rates for juvenile Chinook than more permanent habitats 

in either the floodplain or river.

Jungwirth, M., S. Muhar, et al. 1995. The 

effects of re-created instream and ecotone 

structures on the fish fauna of an epipotamal 

river. Hydrobiologia 303:195–206.

Remeander. Number of fish species increased from 10 in straightened sections to 

19 in restructured sites.
119

Jungwirth, M., S. Muhar, et al. 2002. 

Reestablishing and assessing ecological 

integrity in riverine landscapes. Freshw. Biol. 

47(4):867–887.

Reconnection. Overall evaluation of ecological integrity of three reaches was 

0.22, 0.54, and 0.37. Includes physical habitat conditions, vegetation, and fish 

fauna.

Jutagate, T., C. Krudpan, et al. 2005. Changes 

in the fish catches during a trial opening of 

sluice gates on a run-of-the-river reservoir in 

Thailand. Fish. Manag. Ecol. 12(1):57–62.

Flooding—sluice gates open on dam. Catch per unit effort ranged from 0.38 to 

1.70 and 0.61 to 2.71 kg fisherman−1 night−1 downstream and upstream of the 

dam, respectively. Month percent index of relative importance of the fish species 

caught varied between months.

Klein, L. R., S. R. Clayton, et al. 2007. Longterm monitoring and evaluation of the Lower 

Red River Meadow Restoration Project, 

Idaho, USA. Restor. Ecol. 15(2):223–239.

Channel length increased 60%, resulting in a 60% increase in sinuosity. Median 

bankfull velocity was significantly slower immediately following restoration, but 

not 3 years later. Model simulation showed an average increase in postrestoration 

hydroperiod by more than 25 days or 200%. Mean native plant cover increased 

from 32% in 1997 to 57% in 2001, then 65% in 2003. Mean native greenline 

plant cover decreased from 49 to 43%. Total number of habitat units increased 

by 52% from 48 to 73, then increased to 102 in 2003. Proportion of fines 

decreased significantly. Temperatures exhibited significant increasing temporal 

trends. Salmonid densities fluctuated and ranged from 7.1 fish/100 m2 in 2003 to 

27.8 fish/100 m2 in 2001. No significant increasing trend in salmonid density or 

percent composition was detected in the restored reach. Annual Chinook salmon 

redd density fluctuated, no significant increase. Bird numbers increased 

significantly from 52 in 1996 to 91 in 2003.

Kronvang, B., L. M. Svendsen, et al. 1998. 

Restoration of the rivers Brede, Cole, and 

Skerne: A joint Danish and British EU-LIFE 

demonstration project, III−Channel 

morphology, hydrodynamics, and transport of 

sediment and nutrients. Aquat. Conserv.: 

Mar. Freshw. Ecosyst. 8(1):209–222.

No fish. Reducing the bankfull capacity, raising the bed level, and lowering the 

bank level allowed an increase in flooding frequency and in the amount of water 

passing onto the floodplain in all three rivers. In the River Brede, restoration of 

the natural hydrological contact between the river and its floodplain resulted in 

high deposition of sediment (189 t year−1) and sediment associated phosphorus 

(770 kg P year−1). Construction caused excessive downstream loss of sediment 

and phosphorus.
120

Langler, G. J., and C. Smith. 2001. Effects of 

habitat enhancement on 0-group fishes in a 

lowland river. Regul. Rivers: Res. Manag.

17(6):677–686.

Construction of off-channel habitats. Abundance (t = 3.94. df = 61, P < 0.001) 

and diversity (t = 6.48, df = 50, P ≤ 0.001) of 0-group fishes (nonsalmonid) was 

significantly higher in treatment areas.

Lister, D. B., and W. E. Bengeyfield. 1998. An 

assessment of compensatory fish habitat at 

five sites in the Thompson River system. Rep. 

2444. DFO, Habitat and Enhancement 

Branch, Vancouver, BC.

Constructed ponds. No clear numbers. At four of five study sites, the 

compensatory habitat was functioning to effectively offset the original impacts. 

Natural colonization appeared capable of revegetating disturbed marshes and 

riparian areas in a relatively short time.

Martin, A. E., M. S. Wipfli, et al. 2010. Aquatic 

community responses to salmon carcass 

analog and wood bundle additions in restored 

floodplain habitats in an Alaskan stream. 

Trans. Am. Fish. Soc. 139(6):1828–1845.

Juvenile coho salmon. Biofilm chlorophyll a concentrations were 4–10 times

higher in analog-enriched treatments than in the control and wood treatments. No 

treatment effects were detected in benthic invertebrate density; however, 

treatment differences were detected in coho diets, with nearly twice the amount in 

invertebrate abundance and biomass in the analog and analog plus wood 

treatments. Juvenile coho density and biomass were significantly higher in the 

wood treatment than in the analog plus wood treatment. Body condition of coho 

was highest in the two analog-enriched treatments; juveniles in these habitats 

showed nearly two times the condition increase of fish in control and wood 

treatments.

Marttin, F., and G. J. De Graaf. 2002. The 

effect of a sluice gate and its mode of 

operation on mortality of drifting fish larvae 

in Bangladesh. Fish. Manag. Ecol. 9(2):123–

125.

Mortality rate (percent of total larvae recaptured) of carp hatchlings (±SE) for 

undershot and overshot operations of the sluice gates. Overshot = 11.8 (±3.6),

undershot = 44.0 (±5.6).

McKinstry, M. C., and S. H. Anderson. 1999. 

Attitudes of private- and public-land managers 

in Wyoming, USA, toward beaver. Environ. 

Manag. 23(1):95–101.

Beaver reintroduction. Lost 30% of beaver to mortality and 51% to emigration 6 

months after release. Survival estimates were 0.49 (SE = 0.068) for 180 days and 

0.433 (SE = 0.084) for 360 days. Beaver 2–3.5 years old had higher average

success than older or younger beaver.
121

McKinstry, M. C., P. Caffrey, et al. 2001. The 

importance of beaver to wetland habitats and 

waterfowl in Wyoming. J. Am. Water Resour. 

Assoc. 37(6):1571–1578.

Beaver reintroduction. Survey of land managers found that beaver had been 

removed from 23% of streams managers knew of. There are more than 3,500 km 

of streams where beaver could improve habitat. Riparian width in streams with 

beaver ponds averaged 33.9 m compared to 10.5 m without. There are more 

ducks in areas with beaver ponds. Waterfowl are quick to respond to creation of 

beaver-created wetlands.

Moerke, A. H. 2004. Landscape influences on 

stream ecosystems: Implications for 

restoration and management. Diss. Abstr. Int. 

B Sci. Eng. 65(1):46.

Dissertation abstract only. Remeander. Upstream sediment is limiting factor, so 

restoration should target the scale at which degradation occurs. Anthropogenic 

factors explained most variation in stream conditions. Forested streams were 

least degraded in terms of water quality, habitat, and fish. Agricultural streams 

without buffers were the most degraded and urban and agricultural streams with 

buffers were intermediate.

Moerke, A. H., K. J. Gerard, et al. 2004. 

Restoration of an Indiana, USA, stream: 

Bridging the gap between applied and basic 

lotic ecology. J. North Am. Benthol. Soc. 

23:647–660.

Remeander. One year post-treatment, periphyton, invertebrates, and fish 

recovered or exceeded levels in the control reach, but 5 years post-treatment, 

invertebrate diversity and fish abundance in restored reaches were similar to or 

below levels in the control reach.

Moerke, A. H., and G. A. Lamberti. 2003. 

Responses in fish community structure to 

restoration of two Indiana streams. N. Am. J. 

Fish. Manag. 23(3):748–759.

Remeander. Increase in size distribution and number of redds for trout. Fish 

community changed from rheophilic species to highly tolerant, slow-water 

species. Fish population and community metrics for one creek suggested nearly 

complete fish colonization by 9 months after restoration, although metrics seldom 

exceeded the levels of unrestored, channelized reaches. Trout populations 

responded rapidly to the restoration by spawning only in the restored reaches.

Moerke, A. H., and G. A. Lamberti. 2004. 

Restoring stream ecosystems: Lessons from a 

midwestern state. Restor. Ecol. 12(3):327–

334.

On-site assessments revealed that restored reaches had significantly lower stream 

widths and greater depths than upstream unrestored reaches, but riparian canopy 

cover often was lower in restored than in unrestored reaches.
122

Morley, S. A., P. S. Garcia, et al. 2005. 

Juvenile salmonid (Oncorhynchus spp.) use of 

constructed and natural side channels in 

Pacific Northwest rivers. Can. J. Fish. Aquat. 

Sci. 62(12):2811–2821.

Juvenile salmonid use of constructed vs. natural side channels. Total salmonid 

density (fish × m−2) in summer was 2.14 (±1.60) and 0.11 (±0.89) for constructed 

and reference sites, respectively; in winter it was 0.81 (±0.87) and 0.81 (±0.96), 

respectively. Coho salmon densities were higher in constructed channels and 

trout densities were higher in reference channels during winter. Both channel 

types supported high densities of juvenile coho during summer and winter. 

Constructed channels were deeper and warmer in winter and cooler in the 

summer than natural channels, but had lower physical habitat diversity, wood 

density, and canopy coverage.

Muhar, S., M. Jungwirth, et al. 2008. Restoring 

riverine landscapes at the Drau River: 

Successes and deficits in the context of 

ecological integrity. In H. Habersack, H. 

Piegay, et al., Gravel-bed rivers VI: From 

process understanding to river restoration, p. 

779–803. Elsevier B.V., Amsterdam, 

Netherlands.

Not a lot of good numbers. Results showed improvements of the habitat and fish 

ecological situation in rehabilitated sites. Juvenile grayling benefitted from 

increased areas of shallow habitats; the ecological status improved between 0.2 

and 0.9 ecological classes, depending on the spatial extent of the measures. Both 

brown trout and rainbow trout showed higher values in the channelized sections.

Muhar, S., G. Unfer, et al. 2004. Assessing 

river restoration programmes: Habitat 

conditions, fish fauna, and vegetation as 

indicators for the possibilities and constraints 

of river restoration. In D. Garcia de Jalon and 

P. V. Martinez (eds.), Proceedings of the Fifth 

International Conference on Ecohydraulics–

Aquatic habitats: Analysis and restoration, 

p. 300–305. International Association of 

Hydraulic Engineers, Madrid, Spain.

Levee removal and constructed side channel. Aquatic area increased by 67%,

initiating five additional aquatic habitat types, riparian and floodplain vegetation

restoration was successful in terms of characteristic plant species and 

associations, and new shallow water areas in restored areas were utilized by 

juvenile graylings of 70–140 mm more than twice as often as in unrestored

stretches.
123

Nagayama, S., Y. Kawaguchi, et al. 2008. 

Methods for and fish responses to channel 

remeandering and large wood structure 

placement in the Shibetsu River Restoration 

Project in northern Japan. Landsc. Ecol. Eng. 

4(1):69–74.

Remeander and large woody debris. No numbers. Before wood placement, few 

small masu salmon were observed in lateral scour pools; 1 year after wood 

placement, juvenile and adults were abundant and some lentic and benthic fish 

species were found around the wood structures. In winter after wood placement, 

some salmonids (chum salmon) returned from the ocean. No fish were observed 

in lateral scour pools without wood and wood structures tended to be used by 

more fish species compared to areas without wood.

Nakano, D., and F. Nakamura. 2006. Responses 

of macroinvertebrate communities to river 

restoration in a channelized segment of the 

Shibetsu River, northern Japan. River Res. 

Appl. 22(6):681–689.

No fish. The shear stress of the river edge in reconstructed meanders and groyne 

reaches was lower than that in a channelized reach. The edge habitat near the 

streambank created by the reconstructed meander and groyne reaches had higher 

total density and taxon richness of invertebrates than those in channelized 

reaches.

Nakano, D., and F. Nakamura. 2008. The 

significance of meandering channel 

morphology on the diversity and abundance 

of macroinvertebrates in a lowland river in 

Japan. Aquat. Conserv.: Mar. Freshw. 

Ecosyst. 18(5):780–798.

No fish. No good numbers. Macroinverebrate response to remeander. The 

natural meandering and restored meandering reaches showed higher crosssectional diversity in physical variables and total taxon richness across a reach 

than did the channelized reach. Almost all taxa observed in the natural and 

restored reaches were concentrated in the shallowest marginal habitats near the 

banks. Shear velocity increasing with water depth had a negative association 

with invertebrate density and richness.

Neilsen, M. 2002. Lowland stream restoration 

in Denmark: Background and examples. J. 

Chartered Institution of Water and Environ. 

Manag. 16(3):189–193.

Remeander, improve hydraulic interaction between river and meadows, restore 

wetlands. Water storage increased, natural habitat improved for plants and 

animals including salmon, and water quality increased. No numbers.

Payne, A. I., and V. Cowan. 1998. Review of 

stock enhancement in the floodplains of 

Bangladesh. In T. Petr, Inland fishery 

enhancements, p. 153–158. FAO Fisheries 

Tech. Rep. 374. FAO, Rome.

Carp and catfish. Yields increased from 1,863 kg/ha to 11,384 kg/ha, which 

partly resulted from improved access to fishing and number of fishing days 

increased from 396 to 810 over a year. The percentage of the catch due to major 

carp and large catfish increased from 2% to 24%, indicating that immigration and 

recruitment had increased substantially.
124

Pedersen, M. L., J. M. Andersen, et al. 2007. 

Restoration of Skjern River and its valley: 

Project description and general ecological 

changes in the project area. Ecol. Eng. 

30:131–144.

Remeander. River valley changed from agricultural fields into meadows with a 

rapid succession in plant species. The new river was rapidly colonized with 

plants and invertebrates from upstream reaches. New shallow lakes and meadows 

caused a minor increase in predation of brown trout and Atlantic salmon due to 

the increased populations of fish-eating birds. Lampreys were found at 75% of 

the investigated locations both before and after restoration, soft rush community 

increased from 2% to 12%, number of plant species associated with humid soils 

increased from 3 to 7, and wetland species increased from 1 to 23. Area became 

an important feeding and roosting site for migratory birds. Breeding possibilities 

and general survival possibilities improved for the common frog and moor frog. 

Otters were spotted in 12 of 19 sites visited before the project and 18 of 20 sites 

after. Floating water plantain coverage had a slight decrease in occurrence after 

restoration.

Pedersen, T. C. M., A. Baattrup-Pedersen, et al. 

2006. Effects of stream restoration and 

management on plant communities in lowland 

streams. Freshw. Biol. 51(1):161–179.

Compared macrophyte communities in natural streams, restored streams 

(remeandered), and channelized streams. Macrophyte communities were similar 

in restored and natural streams (30 and 33 species in restored and natural vs. 16 in 

channelized, Shannon diversity 2.7 and 2.8 vs. 1.4). Bank morphology and 

management and bed depth strongly influence macrophyte communities.

Raastad, J. E., A. Lillehammer, et al. 1993. 

Effect of habitat improvement on Atlantic 

salmon in the regulated River Suldalslagen. 

Regul. Rivers: Res. Manag. 8(1–2):95–102.

Built a rearing channel where water flow and substrate can be controlled. 

Physical habitat improved with the density of benthic animals. Survival of age 

1+ salmon was 30%. Addition of 115 g wheat/m2 resulted in a threefold increase 

in benthic fauna compared to control area. Largest increase was in Chironomidae 

in August-September.

Rahman, M., D. A. Capistrano, et al. 1999. 

Experience of community managed wetland 

habitat restoration. In H. A. J. Middendorp, P. 

M. Thompson, et al. (eds.), Sustainable inland 

fisheries management in Bangladesh, p. 111–

121. ICLARM, Makati City, Philippines.

Canal rehabilitation to reestablish fish migration and fish conservation and create 

fish sanctuaries. Catch in beel and floodplain increased from 2,481 kg to 12,222 

kg and from 1,451 kg to 5,181 kg in pagars. Major carp catch increased from 29 

kg to 1,221 kg in pagars and species recorded increased from 46 to 59.
125

Richards, C., P. J. Cernera, et al. 1992. 

Development of off-channel habitats for use 

by juvenile Chinook salmon. N. Am. J. Fish. 

Manag. 12:721–727.

Excavated channels to reconnect ponds to river. Highest juvenile Chinook 

salmon density (5.2/m2) was in the new channel habitat with cover, low water 

velocity, and moderate depths.

Richardson, C. J., P. Reiss, et al. 2005. The 

restoration potential of the Mesopotamian 

marshes of Iraq. Science 307(5713):1307–

1311.

No numbers. Reflooded marsh area shows rapid reestablishment, high 

productivity, and reproduction of native flora and fauna. Survey 1 year after 

reflooding indicates that water flowing into the marshes from the Euphrates and 

especially the Tigris is of higher quality than originally hypothesized, and as a 

result, early successional stages of marsh restoration are occurring. There is 

partial reestablishment of many of the dominant plant species, but biomass and 

species numbers are low compared with historical records at one site. 

Chlorophyll a concentrations reveal mesotrophic conditions at all sites.

Rohde, S., M. Schutz, et al. 2005. River 

widening: An approach to restoring riparian 

habitats and plant species. River Res. Appl. 

21(10):1075–1094.

No numbers. River widening in general was found to increase the instream 

habitat heterogeneity and enhance the establishment of pioneer habitats and 

riparian plants. Ability of widenings to host typical riparian species and to 

increase local plant diversity depends strongly on the distance to near-natural 

stretches.

Roni, P., S. A. Morley, et al. 2006a. Coho 

salmon smolt production from constructed and 

natural floodplain habitats. Trans. Am. Fish. 

Soc. 135:1398–1408.

Analyzed smolt trap data from 30 constructed and natural floodplain (FP) 

habitats. Constructed FP habitats produced coho salmon smolts of similar size 

and density as those in natural FP habitats. Mean coho smolt densities and 

lengths from restored FP habitats were similar to or higher than those in natural 

FP habitats. Variation in smolt production among sites generally increased as 

wetted area increased. Shoreline irregularity was positively correlated with smolt 

density, but negatively with smolt size.
126

Rosenfeld, J. 2005. Annual report to Habitat 

Conservation Trust Fund, Vancouver, B.C.

Appendix 3: Effectiveness assessment of offchannel habitat structures. B.C. Ministry of 

Water, Land, and Air Protection, Aquatic 

Ecosystem Science Section, Vancouver.

Stream off-channel habitats produce higher numbers and biomass of juvenile parr 

during summer and fall than pond off channels (mostly coho salmon data). Parr 

abundance in channels was approximately four times higher than in other habitat 

types and total biomass was also higher in channels (8.01 g/m2 in channels 

compared to 2.37 g/m2 in ponds) Average parr size tended to be higher in ponds 

than in channels (5.98 g vs. 3.14 g) and small ponds appear to be more productive 

per m2 than large ponds. Smolt production per unit area in the spring is not 

statistically different between ponds and stream off channels. Biomass of drifting 

invertebrates in inlet enclosures was 10 times higher than drifting biomass in 

enclosure outlets.

Rosenfeld, J. S., E. Raeburn, et al. 2008. 

Effects of side channel structure on 

productivity of floodplain habitats for 

juvenile coho salmon. N. Am. J. Fish. 

Manag. 28(4):1108–1119.

Juvenile coho salmon. Review of studies. Average density and biomass of coho 

parr were significantly higher in stream-type side channels (3.4 parr/m2 and 8.01 

g/m2, respectively) than in pond-type side channels (0.8 parr/m2 and 2.37 g/m2). 

Although total parr biomass was three times higher in stream-type side channels, 

average parr weight was 47% lower. Parr abundance declined from late summer 

to early spring in both side channel types, but appeared to decrease more quickly 

in stream-type side channels. Fish density in a single off channel or mainstem 

complex that contained both stream and pond habitats was also higher in stream 

habitats, although fish were significantly larger in pond habitats than in stream 

habitats. Parr density in stream-type side channels was constant with increasing 

channel size, whereas density in pond-type side channels was a decreasing 

function of side channel area. Smolt density was also a decreasing function of 

total side channel area.

Schmutz, S., C. Giefing, et al. 1998. The 

efficiency of a nature-like bypass channel for 

pike-perch (Stizostedion lucioperca) in the 

Marchfeldkanalsystem. Hydrobiologia 371:

1–3.

Reconnection via bypass channel. Although more than 57,000 fish of 35 species 

passed the bypass channel, pike-perch were underrepresented. Bypass not 

successful for all species—it represents a bottleneck for the immigration of pikeperch.
127

Schmutz, S., A. Matheisz, et al. 1994. 

Erstbesiedelung des Marchfeldkanals aus 

fischökologischer sicht. [Colonization of a 

newly constructed canal, Marchfeldkanal, by 

fish]. Wissenschaft, Österreichs Fischerei

[Austrian Fisheries] 47:158–178.

In German; key quantitative findings listed here are based on the English 

summary on page 178. Constructed side channel. After 1 year, 40 fish species 

occurred in the system, but densities were very low. Colonization of the canal is 

mainly a result of drift of larval and young-of-the-year fish.

Sear, D. A., A. Briggs, et al. 1998. A 

preliminary analysis of the morphological 

adjustment within and downstream of a 

lowland river subject to river restoration. 

Aquat. Conserv.: Mar. Freshw. Ecosyst. 

8(1):167–183.

No fish. Channel sinuosity was increased with the creation of 21 new bends. 

Bed levels were raised by 0.75m throughout the length of the downstream 

restored reach. Bed slope was marginally increased in the upstream restored 

reach and significantly increased in the downstream restored reach.

Sheng, M. D., M. Foy, et al. 1990. Coho 

salmon enhancement in British Columbia 

using improved groundwater-fed side 

channels. Rep. 2071. DFO Canada, 

Vancouver.

Constructed/excavated to create groundwater-fed channels. Recruited annually 

50–250 coho salmon spawners in the first 3 years. Channels appear to be fully 

seeded each year. Channels can produce up to three coho smolts/m2. Riprap 

armoring can increase smolt productivity more than tenfold (crevices provide 

sanctuary for presmolts). Cover availability is closely related to coho smolt 

abundance in groundwater-fed channels.

Simons, J., C. Bakker, et al. 2001. Man-made 

secondary channels along the River Rhine 

(the Netherlands): Results of postproject 

monitoring. Regul. Rivers: Res. Manag.

17(4–5):473–491.

Constructed secondary channels functioned as a biotope for riverine species. The 

density and number of rheophilic species are influenced by the water level and 

frequent inundation from the high hydrological connectivity. Rheophilic taxa 

made up 4% of the total number of taxa. This percentage increased to 14–21% 

after the creation of the secondary channel.

Sommer, T., B. Harrell, et al. 2001a. 

California’s Yolo Bypass: Evidence that flood 

control can be compatible with fisheries, 

wetlands, wildlife, and agriculture. Fisheries 

26(8):6–16.

References many results from Sommer et al. 2001b. No good numbers. 

Floodplain is a valuable spawning and rearing habitat for splittail and young 

Chinook salmon. Year-class strength is strongly correlated with the duration of 

floodplain inundation. Salmon are most abundant in areas with velocity refuges 

such as trees, shoals, and the downstream portions of levees. Mean salmon size 

increased significantly faster in the floodplain than in the river, suggesting better 

growth rates.
128

Sommer, T. R., M. L. Nobriga, et al. 2001b. 

Floodplain rearing of juvenile Chinook 

salmon: Evidence of enhanced growth and 

survival. Can. J. Fish. Aquat. Sci. 58(2):

325–333.

Floodplain rearing. Juvenile Chinook salmon increased in size substantially 

faster in the seasonally inundated floodplain than in the river. Juveniles released 

in the floodplain were significantly larger at recapture and had higher apparent 

growth rates than those released in the river. Hydrology affects the quality of 

floodplain rearing habitat. Fork length in 1998 was 93.7 mm (±2) in floodplain 

and 85.7 mm (±1.4) in river; in 1999, 89.0 (±2.6) in floodplain and 82.1 (±1.7) in 

river. Apparent growth rate (mm × day−1) in 1998 was .80 (±.06) in floodplain 

vs. 0.52 (±.02) in river; in 1999, 0.55 (±.06) in floodplain and .43 (±03) in river.

Stroh, M., A. Kratochwil, et al. 2005. 

Rehabilitation of alluvial landscapes along 

the River Hase (Ems River basin, Germany). 

Large Rivers 15(1–4):243–260.

Redeveloping pasture. Areas were inoculated with diaspores. After two 

vegetation periods, the plant species composition at the inoculated plots develop 

in the desired direction in contrast to noninoculated plots. The rehabilitated area 

now has high diversity and even includes threatened species. Inoculated plots 

have a significantly higher number of species per plot than noninoculated plots.

Sudduth, E. B., B. A. Hassett, et al. 2011. 

Testing the field of dreams hypothesis: 

Functional responses to urbanization and 

restoration in stream ecosystems. Ecol. Appl. 

21(6):1972–1988.

No fish. Stream metabolism did not differ between stream types in either season 

and nitrate uptake kinetics were not different between stream types in winter. 

During the summer, restored stream reaches had substantially higher rates of 

nitrate uptake than unrestored or forested steam reaches; however, variation in 

stream temperature and canopy cover explained 80% of the variation across 

streams in nitrate uptake.

Thompson, P. M., and M. M. Hossain. 1998. 

Social and distributional issues in open water 

fisheries management in Bangladesh. In T. 

Petr, Inland fishery enhancements, p. 351–

370. Fisheries Tech. Rep. 374. FAO, Rome.

Carp and “small fish.” After restoration, catch from the beel and floodplain 

increased by about six times (part of this increase was due to greater flood extent 

in the second year), while in the floodplain the catch from fish aggregating 

devices (ditches or pagars) increased 3.6 times.
129

Van Liefferinge, C., D. De Smedt, et al. 2003. 

Ecological evaluation for river meandering 

restoration. A case study on five Flemish 

rivers. In C. A. Brebbia (ed.), River basin 

management II, p. 377–387. WIT Press, 

Southampton, Boston.

Twelve Belgian species. Prerestoration evaluation of fish assemblage and the 

macroinvertebrate communities mainly on the population level. Used species 

composition, diversity, and Index of Biological Integrity for fish and the Belgian 

Biotic Index for invertebrates. In one case, the preevaluation showed that 

restoration at the present state would probably not result in a higher ecological 

value; restoring a good water quality would be of higher priority than restoring 

meanders. Meander restoration of four other sites would result in a higher 

ecological value.

Weber, C., E. Schager, et al. 2009. Habitat 

diversity and fish assemblage structure in 

local river widenings: A case study on a Swiss 

river. River Res. Appl. 25(6):687–701.

Twenty species. No good numbers. River widenings vs. canalized reaches. 

Habitat diversity (depth, flow, velocity, cover availability) was considerable 

greater in the two longer widenings (>900 m length) than in the canalized reaches 

and in the shortest widening (300 m), with higher proportions of shallow or deep 

areas of different flow velocities. Rehabilitated reaches showed consistently 

longer shorelines than canalized reaches (32–200% of historic values). No 

overall significant relationship was found between reach type and the number of 

species or total fish abundance. Highest winter abundance was observed in deep, 

well-structured backwaters of rehabilitated reaches. Assemblage structure and 

composition were similar in both reaches.

Zurowski, W., and B. Kasperczyk. 1988. 

Effects of reintroduction of European beaver 

in the lowlands of the Vistula Basin. Acta 

Theriologica 33(12–25):325–338.

Reintroduced 168 beavers. In first year they set up 64 sites. Loss of beaver was 

15% in first year after reintroduction. Forty-four new colonies were eventually 

created. A high birth rate of 1.9 young per litter was observed. Beavers raised in 

a farm for reintroduction are suitable.
130

Riparian/Grazing References (Subtotal is 53 of 409)

Reference Key Quantitative Findings

Briggs, M. K. 1996. Riparian ecosystem 

recovery in arid lands: Strategies and 

references. University of Arizona Press, 

Tucson.

Provides only general information on results of various case studies, no specific 

numbers.

Carline, R. F., and M. C. Walsh. 2007. 

Responses to riparian restoration in the Spring 

Creek watershed, central Pennsylvania. 

Restor. Ecol. 15(4):731–742.

No fish. Buffer strips and bank stabilization, fencing, rock-lined crossings in 

areas with grazing. Few changes were found in channel widths and depths due to 

a drought. Vegetation increased from ≤50% to 100% in nearly all formerly 

grazed buffers. Proportion of fine sediment decreased in one of two treatment 

streams. Suspended sediments during base flow and storm flow decreased 47–

87%. Invertebrate densities increased in both treated streams.

Chen, H., J. X. Zhou, et al. 2005. The impact of 

vegetation restoration on erosion-induced 

sediment yield in the middle Yellow River and 

management prospect. Science in China 

Series D-Earth Sciences 48(6):724–741.

Vegetation restoration on erosion-induced sediment yield. Annual precipitation 

of 530 mm is the critical annual precipitation for forest and grass in the middle 

Yellow River. The rate of watershed forest coverage in key counties should at 

least exceed 30%.

Clary, W. P. 1999. Stream channel and 

vegetation responses to late spring cattle 

grazing. J. Range Manag. 52(3):218–217.

Ten-year grazing study comparing high, medium, and no grazing on Stanley 

Creek, Idaho. Stream channel narrowed (ratios of after/before .54, .52, and .29 

for high, medium, and no grazing, respectively), embeddedness decreased, 

stability increased. Height of willows increased .35, .28, and .4 m for high, 

medium, and no grazing treatments; willow cover increased by 29, 37, and 56% 

in three treatments; and little change was detected in herbaceous cover.

Clary, W. P., N. L. Shaw, et al. 1996. Response 

of a depleted sagebrush steppe riparian system 

to grazing control and woody plantings.

Research Rep. INT-RP-492. U.S. Forest 

Service, Intermountain Research Station, 

Ogden, UT.

Detailed study of riparian response to grazing control with numerous tables that 

are hard to quantify in a few statistics due to multiple measures and treatments. 

Herbaceous plant species increased in growth and vigor under reduced grazing. 

Significant improved stands of cottonwood and willow developed where they 

were artificially planted. No difference in nesting birds or small mammals 7 

years after treatment. Width/depth ratio increased in all treatments except those 

not subjected to grazing.
131

Connin, S. 1991. Characteristics of successful 

riparian restoration projects in the Pacific 

Northwest. Environmental Protection 

Agency, Seattle.

Review of 13 fencing and other similar riparian projects. Results varied by study, 

but overall studies reported increased spawning gravels, bank stability, and 

decrease in channel width and erosion. Twenty-five to 50% increase in 

streambank cover. One project reported increase in smolt production from 0 to 

25 smolts per pool. Fecal coliform also decreased with fencing/livestock 

exclusion.

Cooperman, A. S., S. G. Hinch, et al. 2007. 

Streambank restoration effectiveness: Lessons 

learned from a comparative study. Fisheries 

32(6):278–291.

Grading, plantings, rock deflectors, and fencing. Invertebrate abundance did not 

differ between treatment and control sites, but was affected by channel gradient 

and river segment. Sites did not differ in multivariate space, but treatment sites 

had narrower wetted widths and higher inside banks than control sites. All other 

in-channel response variables and channel gradient did not statistically differ 

between sites.

Dobkin, D. S., A. C. Rich, et al. 1998. Habitat 

and avifaunal recovery from livestock grazing 

in a riparian meadow system of the 

northwestern Great Basin. Conserv. Biol.

12(1):209–221.

Examined recovery of livestock grazing on plots on a small stream in Great 

Basin. Increase in forb and sedge cover. Increase in avian species richness (from 

10 to 12) and abundance (from ≈15 to 30/plot).

Emmingham, W. H., S. S. Chan, et al. 2000. 

Silviculture practices for riparian forests in 

the Oregon coast range. Oregon State Univ., 

Forest Research Laboratory, Corvallis.

Reviewed several conifer conversion projects along the Oregon coast, provided 

only qualitative results. Relatively poor growth and survival due to shade, 

predation (beaver and deer), and competition. Provides recommendations for 

improving project success (control of predation, shade, competition).

Gladwin, D. N., and J. E. Roelle. 1998. 

Survival of plains cottonwood (Populus 

deltoides subsp. Monilifera) and saltcedar 

(Tamarix ramosissima) seedlings in response 

to flooding. Wetlands 18(4):669–674.

Response of saltcedar and cottonwood to fall and spring flooding. Fall flooding 

survival of saltcedar was 0.8% vs. 21% for cottonwood. Spring flooding survival 

was 94% vs. 99% for cottonwood. Fall flooding recommended to control 

saltcedar.

Holmes, T. P., J. C. Bergstrom, et al. 2004. 

Contingent valuation, net marginal benefits, 

and the scale of riparian ecosystem 

restoration. Ecol. Econ. 49(1):19–30.

Economic evaluation of riparian restoration based on cost and survey of “values” 

or “benefits.” Benefit/cost ratio for riparian restoration ranged from 4.03 (for 2 

miles of restoration) to 15.65 (for 6 miles of restoration), demonstrating that 

riparian restoration was cost-effective.
132

Hook, P. B. 2003. Sediment retention in 

rangeland riparian buffers. J. Environ. Qual.

32(3):1130–1137.

Sediment retention on rangeland riparian buffers. Sediment retention ranged 

from 63% to 99%, depending on vegetation type and buffer width. In 6 m wide 

buffers, 94% to 99% retention, regardless of vegetation type or hillslope.

Humphrey, J. W., and G. S. Patterson. 2000. 

Effects of late summer cattle grazing on the 

diversity of riparian pasture vegetation in an 

upland conifer forest. J. Appl. Ecol.

37(6):986–996.

Scottish study looking at effects of grazing on plant species diversity. Grazing 

led to greater species richness, but decrease in vegetation height.

Kauffman, J. B., P. Bayley, et al. 2002. 

Research/evaluate restoration of NE Oregon 

streams: Effects of livestock exclosures 

(corridor fencing) on riparian vegetation, 

stream geomorphic features, and fish 

populations. BPA Rep. DOE/BP-00006210-1. 

Oregon State Univ., Corvallis.

Examined control (grazed) and treatment (grazing exclosure) reaches of 11 

northeast Oregon streams). Results not easily converted to simple quantities of 

change, but significantly higher vegetation cover, composition, and structure and 

species richness. Improvement in geomorphology including channel width, 

depth, and number of pools also detected. Young-of-the-year rainbow trout 

(redband) in ungrazed sections, but no change in parr or adult trout. Redside 

shiners and speckled dace decreased.

Kauffman, J. B., A. S. Thorpe, et al. 2004. 

Livestock exclusion and belowground 

ecosystem responses in riparian meadows of 

eastern Oregon. Ecol. Appl. 14(6):1671–

1679.

Examined livestock exclusion on three sites in middle fork John Day River 9–18 

years after grazing in dry and wet meadows. Total belowground biomass was 

50% and 62% greater in exclosures in dry and wet meadows, respectively. Mean 

infiltration rate was 12.9 times greater (1,191%) and 233% greater in dry and wet 

meadows, respectively.

Keller, C. R., and K. P. Burnham. 1982. 

Riparian fencing, grazing, and trout habitat 

preference on Summit Creek, Idaho. N. Am. 

J. Fish. Manag. 2:53–59.

Fencing to exclude livestock in Summit Creek, Idaho, led to more trout in 

ungrazed sections—1.56 times more fish on average. Also fish in ungrazed 

sections were larger.

Kondolf, G. M. 1993. Lag in stream channel 

adjustment to livestock exclosure, White 

Mountains, California. Restor. Ecol. 

1(4):226–230.

Examined channel morphology within and downstream of grazing exclosure—no 

change in channel width downstream of exclosure despite higher vegetation

height and cover in exclosure.
133

Laffaille, P., J. C. Lefeuvre, et al. 2000. Impact 

of sheep grazing on juvenile sea bass, 

Dicentrarchus labrax L., in tidal salt marshes. 

Biol. Conserv. 96(3):271–277.

Effects of sheep grazing on salt march in France and seabass foraging. Change in 

vegetation following removal of grazing led to more food (invertebrates) for 

seabass. They consumed less invertebrates in grazed areas.

Li, H. W., G. A. Lamberti, et al. 1994. 

Cumulative effects of riparian disturbances 

along high desert trout streams of the John 

Day Basin, Oregon. Trans. Am. Fish. Soc. 

123(4):627–640.

Comparison of shaded and unshaded streams in the John Day Basin. Shaded 

streams cooler by up to 5°C, greater rainbow trout biomass by approximately

twofold in those with canopy vs. those without (hard to estimate average increase 

from graphs).

Long, J. W., A. Tecle, et al. 2003. Marsh 

development at restoration sites on the White 

Mountain Apache Reservation, Arizona. J. 

Am. Water Resour. Assoc. 39(6):1345–1359.

Examined recovery of riparian areas following removal of grazing and seeding in 

White Mountain Apache Reservation. Found emergent wetland plants 4.7% to 

55.5% higher in reaches with perennial flow compared to initial condition. Mean 

cover of aquatic plants declined from 7.4% to 0.2%. As fine sediments and 

emergent vegetation accumulated within the channel, mean cover of coarse 

materials declined from 38.5% to 0.3%. Mean cover of woody plants increased 

from 0.8% to 2.7%.

Lyons, J., S. W. Trimble, et al. 2000. Grass 

versus trees: Managing riparian areas to 

benefit streams of central North America. 

J. Am. Water Resour. Assoc. 36(4):919–930.

Effects of rest rotation grazing on bank erosion and fish. Intensive rest rotation 

grazing and grazing buffers had less bank erosion and fine sediment compared to 

continuous grazing. No effect was detected on trout abundance, Index of 

Biological Integrity, or other physical or biological variables.

Marshall, D. W., A. H. Fayram, et al. 2008. 

Positive effects of agricultural land use 

changes on cold-water fish communities in 

southwest Wisconsin streams. N. Am. J. Fish. 

Manag. 28(3):944–953.

Brown trout. Effects of planting cool- or warm-season grass cover on highly 

erodible croplands along stream corridors. Preplanting fish communities had a 

relatively high diversity of eurythermal species and low cold-water Index of 

Biological Integrity (IBI) scores. They found significant increases in cold-water 

IBI scores over time in streams within the high planting area relative to streams 

within the low planting area. Fish populations in the high planting area shifted 

from eurythermal and tolerant species before planting to stenothermal, cool- and 

cold-water species. Ecological responses within the high planting streams also 

included a reduction in species richness. IBI scores and species richness were 

correlated with phosphorus loading estimates and predicted phosphorus 

reductions were greater with the high planting area.
134

Meals, D. W. 2001. Water quality response to 

riparian restoration in an agricultural 

watershed in Vermont, USA. Water Sci. 

Technol. 43(5):175–182.

Same as Meals and Hopkins 2002, but preliminary findings. See Meals and 

Hopkins 2002 below.

Meals, D. W., and R. B. Hopkins. 2002. 

Phosphorus reductions following riparian 

restoration in two agricultural watersheds in 

Vermont, USA. Water Sci. Technol. 

45(9):51–60.

Examined phosphorous (P) reduction in before-after control-impact watershed 

(2 treatments = 1 control) design to grazing and riparian treatments. 

P concentrations and loads decreased 20% and total P load 20–50%.

Medina, A. L. 2001. A preliminary analysis of 

riparian habitat conditions of the upper Verde 

River. In C. DeCarlo, C. Schlinger, et al. 

(eds.), Verde Watershed Symposium: State of 

the Watershed in 2001, p. 16–24. Northern 

Arizona Univ., Flagstaff.

Examined vegetation and channel conditions in the Verde River, Arizona, 

following grazing removal and large flood. Did not find 1) that the riparian 

habitats were dysfunctional, 2) that recent livestock grazing had a negative effect 

on woody plant densities, or 3) that channel conditions were impaired due to 

excessive sedimentation. The study design limited the ability to detect change. 

Note that the report does not provide clear information on study design very well 

and focuses on changes across basin rather than grazing treatments.

Medina, A. L., J. N. Rinne, et al. 2005. 

Riparian restoration through grazing 

management: Considerations for monitoring 

project effectiveness. In P. Roni (ed.), 

Monitoring stream and watershed restoration, 

p. 97–126. American Fisheries Society 

Bethesda, MD.

Book chapter. Three case studies on grazing removal. First, Rio de Las Vacas 

exclosures, no fish response, streambank stability was 100% in exclosures, but 

64% in grazed areas, overhanging vegetation slightly higher in grazed areas, no 

difference in nutrients, study design confounded results. Second, West Fork 

grazing allotment looked at exclusion of cattle, cattle and elk, or both. Standing 

biomass of vegetation increased in all three treatments, but most in control, no 

fish response. Third, Verde River, no differences in water quality. Vegetation

cover composition and density improved at grazed and ungrazed sites. Numbers

of exotic species have continued to increase.

Medina, A. L., and J. E. Steed. 2002. West Fork 

allotment riparian monitoring study 1993–

1999. U.S. Forest Service, Rocky Mountain 

Research Station, Flagstaff, AZ.

Examination of West Fork grazing allotment (see also Medina et al. 2005) and 

different grazing treatments (with and without cattle and elk). No effects on 

channel morphology or fish (Apache trout) were detected. Little to no response 

in vegetation metrics measured. Results complicated by elk trampling and 

grazing and other environmental factors.
135

Myers, L. H. 1989. Grazing and riparian 

management in southwestern Montana. 

In R. E. Gresswell, B. A. Barton, et al. (eds.), 

Practical approaches to riparian resource 

management: An education workshop, p. 117–

120. U.S. Bureau of Land Management, 

Billings, MT.

Examined 34 grazing allotments in southwest Montana—74% were unsuccessful 

in accommodating a positive riparian vegetation response within a 10 to 20 year 

period, owing mostly to stocking rates and days of grazing. No specifics 

provided other than measurements of plant heights on one plot. Grazed plants 

were 13–86% of ungrazed height, depending on date measured.

Myers, T. J., and S. Swanson. 1995. Impact of 

deferred rotation grazing on stream 

characteristics in central Nevada: A case 

study. N. Am. J. Fish. Manag. 15(2):428–439.

Looked at effects of grazing removal on physical habitat in one watershed and 

rest rotation grazing strategies in two Nevada watersheds. Streambank soil 

stability, type and amount of vegetation cover, and qualities of pools improved in 

all three streams. Bank stability increased 28–37% in streams with and without 

roads and rest rotation grazing. Gravel cobble substrate increased 13% in one 

stream without roads, but not in others.

Myers, T. J., and S. Swanson. 1996. Long-term 

aquatic habitat restoration: Mahogany Creek, 

Nevada, as a case study. Water Resour. Bull. 

32(2):241–252.

Compared recovery from abusive grazing management on two similar northwest

Nevada streams. Mahogany Creek had livestock grazing excluded, while its 

tributary Summer Camp Creek had rest rotation grazing. Bank stability improved 

during grazing period and fine sediment decreased except below road crossings.

Tree cover increased 35% at both streams. Width/depth ratio did not change 

much due to inherent stability of both stream systems.

Nagle, G. N., and C. F. Clifton. 2003. Channel 

changes over 12 years on grazed and ungrazed 

reaches of Wickiup Creek in eastern Oregon. 

Phys. Geogr. 24(1):77–95.

Examined channel cross sections inside and outside a 48-year-old exclosure to 

compare changes following reduction in grazing outside the exclosure (1986 to 

1998). Grazed channels showed improvement, but not all significant. Enclosure 

had narrower width (2.29 vs. 1.45), deeper depth (.23 vs. .32), and narrower

width/depth ratio (14.17 vs. 4.6) than grazed channels.
136

Nerbonne, B. A., and B. Vondracek. 2001. 

Effects of local land use on physical habitat, 

benthic macroinvertebrates, and fish in the 

Whitewater River, Minnesota, USA. Environ. 

Manag. 28(1):87–99.

Examined effects of upland best management practices implementation 

(alternative tillage methods) and riparian buffers (grazed, grass buffer, wooded 

buffer, etc.) throughout the Whitewater River. Physical habitat differed across 

buffers, but not upland treatments. Grass buffers had significantly lower fines 

(1997 means = 60, 38.7, and 59.8 in wood, grass, and grazed), embeddedness 

(1997 means = 69.5, 54.9, and 72.6), and exposed streambanks (1997 means = 

44.6, 4.1, and 27.7) and higher overhanging vegetation (.32, .81, and .27) 

compared to grazed or wood buffers. Benthic invertebrate metrics (rapid 

bioassessment protocols and fish indices of biological integrity) did not differ.

Northington, R. M., and A. E. Hershey. 2006. 

Effects of stream restoration and wastewater 

treatment plant effluent on fish communities 

in urban streams. Freshw. Biol. 51:1959–

1973.

Examined effects of riparian planting and wastewater treatment on aquatic insects 

and fish in urban streams. Restored sites had significantly higher fish richness 

(12 vs. ≈7/100 m for forested and 5 for unrestored) and a trend toward greater 

abundance than unrestored sites (3.5 vs. 2.25 vs. 2/m for forested, unrestored, and 

restored, respectively). Small but insignificant differences existed in abundance 

and Index of Biological Integrity of aquatic insects.

O’Grady, M., P. Gargan, et al. 2002. 

Observations in relation to changes in some 

physical and biological features of the 

Glenglosh River following bank stabilisation. 

In Proceedings of the 13th International 

Salmonid Habitat Enhancement Workshop, 

Hotel Westport, Mayo, Ireland, 16–19 

September 2002, p. 61–77. Central Fisheries 

Board, Dublin, Ireland.

Changes in aquatic flora, invertebrates, and fish following implementation of 

bank stabilization and fencing in Glenglosh River, Ireland. Aquatic moss 

coverage increased from nearly 0 to 50%. Macroinvertebrates went from 5 to 11 

taxa present (before vs. after in treatment sites), fish stocks saw increases in 

brown trout and Atlantic salmon parr after treatment. Annual increases in entire 

length restored range from 1,620 to 5,670 salmon and 3,888 to 9,800 trout.

Opperman, J. J., and A. M. Merenlender. 2000. 

Deer herbivory as an ecological constraint to 

restoration of degraded riparian corridors. 

Restor. Ecol. 8(1):41–47.

Effects of deer herbivory on riparian plantings in Mendocino Country, California. 

Mean density of saplings in deer exclosures was 49/m2 vs. 0.05 in controls (plots 

with deer). Thirty-five percent of saplings were less than 1 m tall in exclosures,

while in controls 97% were less than 1 m.
137

Opperman, J. J., and A. M. Merenlender. 2004. 

The effectiveness of riparian restoration for 

improving instream fish habitat in four 

hardwood-dominated California streams. 

N. Am. J. Fish. Manag. 24(3):822–834.

Examined recovery of channel morphology and fish habitat 10–20 years after 

livestock exclusion fences. Channels within exclosures were narrower (≈3 m 

narrower), were cooler (mean August 18.2°C vs. 22.7°C), had greater large 

woody debris (≈275 pieces/ha vs. 75), and had higher tree density (.74 plants/m2

vs. .08). Note that the approximate numbers were from graphs and the other 

numbers were reported in text.

Parkyn, S. M., R. J. Davies-Colley, et al. 2003. 

Planted riparian buffer zones in New Zealand:

Do they live up to expectations? Restor. Ecol. 

11(4):436–447.

Examined effects of fencing and planting on nine buffer zones 2–24 years after 

fencing. Treatments had better water quality and channel stability, but nutrient 

and fecal contaminant levels were variable. Macroinvertebrates did not show 

significant changes toward clean water taxa and macroinvertebrate taxa richness

was on average 3.42 higher in controls than treatments. Study suggests planted 

reaches may need to be longer.

Penczak, T. 1995. Effects of removal and 

regeneration of bankside vegetation on fish 

population dynamics in the Warta River, 

Poland. Hydrobiologia 303(1–3):207–210.

Effects of removal and recovery of vegetation on fish in the Warta River. Species 

diversity decreased from 17 before to 11 following vegetation removal. Standing 

stock increased from 31.9 to 36.5, 66.2, and 40.9 in 3 years following removal 

and during alder and osier recovery.

Platts, W. S. 1981. Impairment, protection, and 

rehabilitation of Pacific salmonid habitats on 

sheep and cattle ranges. In T. J. Hassler (ed.), 

Proceedings: Propagation, Enhancement, and 

Rehabilitation of Anadromous Salmonid 

Populations and Habitat in the Pacific 

Northwest Symposium, p. 82–92. Humboldt 

State Univ., Arcata, CA.

Summarized findings from three studies on grazing. The first was reported in 

Platts and Nelson 1995 and dealt with rest rotation grazing, which was found to

degrade habitat because grazing was more intensive than before. Other studies in 

Nevada (Tabor Creek) and Utah (Big Creek) examined grazing removal 

(exclosures) and found improvements in stream width, depth, percent fines, 

embeddedness, cover, and bank stability. Large tables with statistics are 

provided, but hard to synthesize due to multiple years and treatments.

Platts, W. S., and R. L. Nelson. 1985. Impacts 

of rest-rotation grazing on streambanks in 

forested watersheds in Idaho. N. Am. J. Fish.

Manag. 5:547–556.

Compared effects of rest rotation grazing vs. regular grazing management in 11

streams. Rest rotation resulted in 8–12% greater usage of riparian areas than 

adjacent range or pasture. Rest rotation grazing also led to decline in streambank 

stability. This study indicates that improperly controlled rest rotation grazing can 

lead to more intensive grazing than expected and degradation of riparian zones 

and stream channels.
138

Rinne, J. N. 1999. Fish and grazing 

relationships: The facts and some pleas. 

Fisheries 24(8):12–21.

Review article—also discusses case studies examined in Medina et al. 2005. 

Most studies did not do statistical analysis and were confounded by management 

actions or natural disturbance (floods, elk, beaver, etc.). See Medina et al. 2005

for details.

Robertson, A. I., and R. W. Rowling. 2000. 

Effects of livestock on riparian zone 

vegetation in an Australian dryland river. 

Regul. Rivers: Res. Manag. 16(5):527–541.

Examined vegetation structure and composition in paired sites with and without 

livestock in six sites in the Murrumbidgee River. Eucalyptus tree species were up 

to 1,000 times more abundant in areas without livestock and biomass of ground 

cover 10 times more abundant. Species richness did not differ, but plant species 

composition did differ. Coarse particulate organic matter and terrestrial fine 

wood outside of channel were consistently more abundant in areas without 

livestock. Instream fine and coarse wood were higher in areas without livestock 

in the main stem, but not the tributary site. Generally sites where livestock had 

been excluded for more than 50 years had the biggest differences.

Roelle, J. E., and D. N. Gladwin. 1999. 

Establishment of woody riparian species 

from natural seedfall at a former gravel pit.

Restor. Ecol. 7(2):183–192.

Eradicating saltcedar by reflooding the lower elevations of the annual drawdown 

zones each fall. After 3 years, at least one of three native woody species survived 

on 41.1% of the plots, while saltcedar was present on only 6.1%.

Schilling, K. E., and C. A. Thompson. 2000. 

Walnut Creek watershed monitoring project, 

Iowa: Monitoring water quality response to 

prairie restoration. J. Am. Water Resour. 

Assoc. 36(5):1101–1114.

A paired watershed study was used to determine the effects of converting row 

crop to native prairie in Iowa. Land use changes were implemented on 19.4 % of 

the basin. The first 3 years of monitoring show encouraging signs, but no 

definitive water quality improvements (nitrate, pesticides, etc.) have been 

detected.

Sovell, L. A., B. Vondracek, et al. 2000. 

Impacts of rotational grazing and riparian 

buffers on physicochemical and biological 

characteristics of southeastern Minnesota, 

USA, streams. Environ. Manag. 26(6): 629–

641.

Examined fish, water quality, macroinvertebrates, and physical habitat to 

different treatments—continuous grazed, rest rotation, grass buffers, and wood 

buffers. Fecal coliform and turbidity were higher at continuously grazed than rest 

rotation sites. Percent fines was higher in wood than grass buffer sites. Benthic 

macroinvertebrates were not consistently different across grazed or buffer types. 

Fish abundance was related to buffer type rather than grazing practice.
139

Sprenger, M. D., L. M. Smith, et al. 2002. 

Restoration of riparian habitat using 

experimental flooding. Wetlands 22(1):49–

57.

Saltcedar eradication using root plows, herbicides, and floodings. Mechanically 

cleared areas had fewer resprouts (26 per ha) than chemically treated areas (2,500 

per ha). Saltcedar and cottonwood seedling density and cottonwood survival 

were greater in the mechanically treated areas than in the chemically treated 

areas. Cottonwood seedling density and survival did not differ between 5 cm/day 

and 10 cm/day stage drawdowns.

Stuber, R. J. 1985. Trout habitat, abundance, 

and fishing opportunities in fenced vs.

unfenced riparian habitat along Sheep Creek, 

Colorado. In R. R. Johnson, C. D. Ziebell, et 

al. (tech. coords.), Riparian ecosystems and 

their management: Reconciling conflicting 

uses, p. 310–314. First North American 

Riparian Conference, 1985 April 16–18, 

Tucson, AZ. Gen. Tech. Rep. RM-GTR-120. 

U.S. Forest Service, Rocky Mountain Forest 

and Range Experiment Station, Fort Collins, 

CO.

Examined trout and trout habitat along a fenced and unfenced Colorado stream. 

Fish habitat within fenced areas was narrower, deeper, less altered, and had more 

streamside vegetation than unfenced sections. Trout standing stock was two

times higher in fenced areas. There was more nongame fish in unfenced areas.

Suren, A. M., and S. McMurtrie. 2005. 

Assessing the effectiveness of enhancement 

activities in urban streams: II. Responses of 

invertebrate communities. River Res. Appl.

21(4):439–453.

Examined response of macroinvertebrates to restructuring and riparian planting of 

five urban streams in Christchurch, New Zealand, before and 5 years after. Only 

small changes were noted with only subtle shifts in overall abundance, species 

evenness, diversity, and ordination.

Suren, A. M., T. Riis, et al. 2005. Assessing the 

effectiveness of enhancement activities in 

urban streams: I. Habitat responses. River 

Res. Appl. 21(4):381–401.

Examined response of habitat to restructuring and riparian planting of five urban 

streams in Christchurch, New Zealand, before and 5 years after restoration. 

Treated sites had generally higher vegetation cover and increasing overhanging 

riparian vegetation. Stream enhancement increased variability in velocity and 

substrate changed as concrete and timber line channels were converted to stream 

channel.
140

Sweeney, B. W., S. J. Czapka, et al. 2002. 

Riparian forest restoration: Increasing success 

by reducing plant competition and herbivory. 

Restor. Ecol. 10(2):392–400.

Examined success of riparian forest planting techniques (bare root vs. 

containerized), herbivory (tree shelters), and weed control (herbicide, mowing, 

tree mats) for oak, birch, and maple at two riparian sites near Chester River, 

Maryland. Results of four growing seasons showed no significant difference in 

survival or growth between bare-root and containerized seedlings. Overall 

survival and growth was different for sheltered and unsheltered seedlings (49% 

and 77.6 cm vs. 12.1% and 3.6 cm) across species and weed control treatments. 

The highest 4-year survival was associated with seedlings protected by shelters 

and herbicide (88.8%/125.7 cm) and shelters and weed matts (57.5%/73.5 cm). 

Thus only a combination of shelters and weed protection provided had 

survivorship high enough to be considered successful (>50%).

Taylor, J. P., and K. C. McDaniel. 1998. 

Restoration of saltcedar (Tamarix sp.)–

infested floodplains on the Bosque del Apache 

National Wildlife Refuge. Integrated systems 

for noxious weed management on rangelands. 

Weed Technol. 12:345–352.

Saltcedar eradication using herbicide, burning, and mechanical control—and 

planting of cottonwood and black willows. Saltcedar resprouts were still 

common after burning, herbicides, and bulldozing. Replanting resulted in 

cottonwood survival of more than 80% 4 years after planting. Deep tillage to 3 m 

and drip irrigation for 165 days resulted in 100% of cottonwood and black willow 

survival when plantings were made on a dredge spoil site.

Wohl, N. E., and R. F. Carline. 1996. Relations 

among riparian grazing, sediment loads, 

macroinvertebrates, and fishes in three central

Pennsylvania streams. Can. J. Fish. Aquat. 

Sci. 53:260–266.

Examined riparian grazing impacts on three streams (two grazed, one ungrazed). 

Annual sediment loads were lower in ungrazed stream (113 metric tons vs. 255 

and 273 metric tons). Substrate permeability and densities of invertebrates were 

higher in ungrazed stream. Densities of brown trout were 5–23 times higher in 

ungrazed than two grazed streams.
141

Wootton, J. T. 2012. River food web response 

to large-scale riparian zone manipulations. 

Plos One 7(12).

Coho salmon, steelhead, and cutthroat trout. Reducing riparian canopy cover 

caused trapped leaf litter to decline by two-thirds, UV radiation to increase 

twelvefold, and photosynthetically active radiation to increase 42-fold. Water 

temperature, benthic substrate, and variation in water depth did not differ 

statistically with treatment. Nutrients, dissolved organic carbon, and silicates did 

not vary significantly with riparian treatment. Algal production increased

thirteenfold, grazer-free algal accrual increased 55-fold, algal standing biomass 

increased by 60%, and algal standing chlorophyll a increased 2.4-fold. Aquatic 

insect abundance increased sevenfold, with all major taxonomic groups showing 

elevated populations. Densities of juvenile salmonids increased on average 77% 

in manipulated reaches.

Sediment/Road References (Subtotal is 27 of 409)

Reference Key Quantitative Findings

Bergeron, K. D. 2003. The effects of an organic 

soil amendment on native plant establishment 

and physical soil properties on an obliterated 

forest road. Master’s thesis. Univ.

Washington, College of Forest Resources, 

Seattle.

Effect of different combinations of soil treatments on vegetation cover and 

biomass. Results showed that biosolids, compost, and fertilizer increased native 

plant biomass and vegetation cover. Presence of nonnatives had no impact on 

native plant biomass. In a second study, saturated hydraulic conductivity rates 

were examining biosolids, application of fertilizer, and straw. No significant

difference was found among treatments. The highest vegetative cover was found

in the 10 cm biosolids compost application (90%), compared to the control (57%) 

and fertilizer treatments (59%). The difference between the three biosolids 

compost amendments and the control and fertilizer remained statistically 

significant. The greatest gain in biomass was observed in biosolids compost 

treatments, with a mean biomass of 53 g in the 2.5 cm application, 65 g in the 5 

cm application, and 80 g in the 10 cm application. The biomass was 33 g for the 

control and 37 g for fertilizer. The no seed/hay treatment had the highest mean 

total plant biomass (69 g), compared to the seed treatment (47 g), seed and hay 

treatment (48 g), and hay treatments (49 g).
142

Bloom, A. L. 1998. An assessment of road 

removal and erosion control treatment 

effectiveness: A comparison of 1997 storm 

erosion response between treated and 

untreated roads in Redwood Creek basin, 

northwestern California. Master’s thesis. 

Humboldt State Univ., Arcata, CA.

Examined sediment delivery and erosion on treated and untreated roads. Treated 

roads yielded significantly less erosion and sediment delivery to streams. On 

upper and middle hillslope roads, the untreated roads contributed 27 times more 

sediment per mile to streams than treated roads, and 59 times more sediment per 

mile to streams than minimally treated roads. The lower hillslope untreated roads 

contributed 1.5 times more sediment per mile of road to streams than treated 

roads, and 1.1 times more sediment per mile of road to streams than minimally 

treated roads. On the upper and middle hillslopes, more than four times as many 

road failures were initiated on treated roads than minimally treated or untreated 

roads. On the lower hillslopes, minimally treated roads initiated two times as 

many road failures as the treated roads and more than five times as many as the 

untreated roads.

Brown, T. M. 2002. Short-term total 

suspended-solid concentrations resulting from 

stream crossing obliteration in the Clearwater 

National Forest, Idaho. Master’s thesis. Univ.

Washington, Seattle.

Effects of stream crossing obliteration. Downstream turbidity was significantly 

higher except at mitigated sites, which were not different upstream or 

downstream of treatment. Total suspended-solid concentrations upstream ranged 

from 1.0 to 5.7 mg/L; downstream concentrations were highly variable, ranging 

from 2.9 to approximately 68,500 mg/L. Upstream suspended sediment yields 

ranged from 0.1 to 0.8 kg, while downstream yields ranged from 0.8 to 95.4 kg. 

The use of two sediment traps reduced peak concentrations an order of magnitude 

from 68,500 mg/L to 3,000 mg/L, and suspended sediment yields 10 to 30 times.

Burroughs Jr., E. R., and J. G. King. 1989. 

Reduction of soil erosion on forest roads. 

U.S. Forest Service, Intermountain Research 

Station, Ogden, UT.

Literature review summarizing major findings of other studies and providing 

recommendations to managers.

Carter, T. L., and T. C. Rasmussen. 2005. Use 

of green roofs for ultra-urban stream 

restoration in the Georgia Piedmont (USA). 

In K. J. Hatcher (ed.), Proceedings of the 2005 

Georgia Water Resources Conference. Univ.

Georgia, Athens.

Green roofs for urban stream restoration—for 32 storm events tested, green roof 

stormwater retention ranged from 39% to 100%.
143

Cloyd, C., and K. Musser. 1997. Effectiveness 

of road stabilization. In H. Plumley (ed.), 

Assessment of the effects of the 1996 flood on 

the Siuslaw National Forest, p. 19–23. U.S. 

Dept. Agriculture, Siuslaw National Forest, 

Corvallis, OR.

Stabilization reduced road-related impacts—67% of failures occurred on 

untreated roads.

Cotts, N. R., E. F. Redente, et al. 1991. 

Restoration methods for abandoned roads at 

lower elevations in Grand Teton National 

Park, Wyoming. Arid Soil Res. Rehabil.

5(4):235–249.

Examined different road surface treatments for abandoned roads—top soil 

significantly increased plant cover. Indigenous plant materials that were 

collected on site produced greater plant cover (23%) than the native materials 

(19%) purchased from a commercial supplier. Nonseeded, topsoiled treatments 

produced significant plant community development (18% cover), resulting from 

natural invasion from local intact communities. Nontopsoiled, scarified 

treatments seeded to indigenous materials provided appreciable plant cover (12%) 

following 2 years of growth.

Elseroad, A. C., P. Z. Fule, et al. 2003. Forest 

road revegetation: Effects of seeding and soil 

amendments. Ecol. Restor. 21(3):180–185.

Examined experimental treatments including combination seeding with native 

species, topsoil addition, and mulching. Total cover and plant density was 

significantly higher on all seeded plots. Combinations of treatment were not 

significantly different. Statistics not provided, but graphs suggest seeded 

treatments had approximately 150 plants/m2 2 months after treatment, while 

unseeded had approximately five. Differences 14 months later were 

approximately 75/m2 vs. 10 plants/m2

.

Foltz, R. B. 1998. Traffic and no-traffic on an 

aggregate surfaced road: Sediment production 

differences. In Proceedings of the seminar on 

environmentally sound forest roads and wood 

transport, Sinaia, Romania, 17–22 June, 1996, 

p. 195–204. FAO, Rome.

Traffic and no-traffic on aggregate surfaced road—sediment production from 

marginal was 4–17 times higher than on good quality aggregate. Sections with 

logging truck traffic produced 2–25 times as much sediment.
144

Foltz, R. B., and W. J. Elliot. 1997. Effect of 

lowered tire pressures on road erosion. 

Transportation Research Board Paper No. 

970638. Transp. Res. Rec.: J. Transp. Res. 

Board 1589:19–25.

Sediment eroded from the low-quality aggregate surfaced roads an average of 

45% less with moderately reduced tire pressure than from highway tire pressure 

sections. An average of 80% was measured from the section used by trucks with 

low tire pressure. Lowering tire pressures in logging trucks on unpaved roads can 

reduce the sediment loss from many unpaved road surfaces.

Harr, R. D., and R. A. Nichols. 1993. 

Stabilizing forest roads to help restore fish 

habitats: A northwest Washington example. 

Fisheries 18(4):18–23.

Examined cost of decommissioning roads (stabilizing fills, removing stream 

crossings, recontouring slopes, and reestablishing drainage patterns to reduce 

landslide hazards). In contrast to unused roads, decommissioned roads showed 

no damage following a 50-year event and a severe rain-on-snow event that 

damaged main haul roads in northwest Washington. From 1967 to 1983, 17 roadrelated landslides occurred; after decommissioning (1987–1988) and two large 

events (1989–1990), no failures on decommissioned roads.

Hickenbottom, J. 2000. A comparative analysis 

of surface erosion and water runoff from 

existing and recontoured forest roads: O’Brien 

Creek watershed, Lolo National Forest, 

Montana. Master’s thesis. Univ. Montana, 

Missoula.

Abstract only. Compared existing and contoured roads (removed) in two geology 

and slope classes (>45% and <45%). In all cases, it was found that recontoured 

roads produced sediment and runoff similar to or higher than road segments. 

However, after 1 year, the volume of runoff and erosion greatly decreased to near 

natural slope conditions.

Kitagawa, K., and S. Okawara. 1998. 

Development of a forest road with a newly 

designed sub-base structure. In Proceedings 

of the seminar on environmentally sound 

forest roads and wood transport, Sinaia, 

Romania, 17–22 June, 1996, p. 226–231.

FAO, Rome.

Improved method for constructing roads with a sub-base mat that intercepts flow 

and disperses on downvalley slope. Long-term observations show this method 

functions well after many years and has several advantages over traditional 

construction methods. Short paper, no statistics provided.

Klein, R. D. 1987. Stream channel adjustments 

following logging road removal in Redwood 

National Park. Watershed Rehabilitation 

Tech. Rep. No. 23. National Park Service, 

Redwood National Park, Arcata, CA.

Examined stream channel adjustments following road removal in the park. 

Technical report with multiple regressions but no specific statistics. Adjustments 

in stream channels depended on the amount of organic matter (large woody 

debris) and other roughness elements left at former crossings that prevented scour 

and erosion.
145

Kochenderfer, J. N., and J. D. Helvey. 1987. 

Using gravel to reduce soil losses from 

minimum-standard forest roads. J. Soil Water 

Conserv. 42:46–50.

Compared forest roads with and without 3′′ of gravel. Soil losses from roads 

without gravel were 47 tons/acre vs. 6 tons/acre for graveled roads.

Kohler, E. A., V. L. Poole, et al. 2004. Nutrient, 

metal, and pesticide removal during storm and 

nonstorm events by a constructed wetland on 

an urban golf course. Ecol. Eng. 23:285–298.

Examined effect of constructed wetlands on golf course runoff. Wetland 

successfully reduced concentration of 13 of 17 parameters (all but K, Al, Mg, and 

Si) during storm events. During nonstorm events, wetland reduced N-NO3

/NO2

by 95% and removal was 100% for other measures.

Kolka, R., and M. Smidt. 2001. Revisiting 

forest road retirement. Water Resour. Impact 

3(3):15–18.

Looked at sediment delivery on retired forest roads including recontoured, 

subsoiled, and control plots on roads. Sediment production was lower from 

subsoiled and recontoured than control, with recontouring producing 

approximately 14 g/m2 of sediment vs. 31 g/m2 for subsoiled vs. 34 g/m2 for 

control and 0 for undisturbed hillslope.

Luce, C. H. 1997. Effectiveness of road ripping 

in restoring infiltrating capacity of forest 

roads. Restor. Ecol. 5(3):265–270.

Examined effectiveness of road ripping on infiltration capacity. Results showed 

that road ripping increases hydraulic conductivities enough to reduce risk of 

runoff, but does not restore natural hydraulic conductivity of a forest slope. 

Unripped roads had hydraulic conductivity of 0–4 mm/hr whereas ripped roads 

had 20–40 mm/hr.

Madej, M. A. 2001. Erosion and sediment 

delivery following removal of forest roads. 

Earth Surf. Process. and Landf. 26(2):175–

190.

Erosion and sediment following road removal. Post-treatment erosion on roads 

was related to method of treatment, hillslope position, and date of treatment. 

Sediment delivery from treated roads on upper, middle, and lower hillslopes was 

10, 35, and 550 m3/km of road treated. In contrast, untreated roads produced 

1,500 to 4,700 m3 of sediment per kilometer.

Madej, M. A., B. Barr, et al. 2001.

Effectiveness of road restoration in reducing 

sediment loads. U.S. Geological Survey,

Redwood Field Station, Arcata, CA.

Essentially the same as Madej 2001. See those key findings above.
146

Maynard, A. A., and D. E. Hill. 1992. 

Vegetative stabilization of logging roads and 

skid trails. N. Am. J. Appl. For. 9(4):153–

157.

Stabilization of logging roads—evaluated the effects of fertilizer and mulch 

treatments on plant density. Results were hard to quantify, as findings and 

recommendations vary by whether the site was sunny, shady, or wet. Addition of 

fertilizer and lime enhanced plant density and survival at all sites.

McCaffery, M., T. A. Switalski, et al. 2007. 

Effects of road decommissioning on stream 

habitat characteristics in the South Fork 

Flathead River, Montana. Trans. Am. Fish. 

Soc. 136(3):553–561.

No good numbers. Significant positive correlations were found between the 

percent of fine sediment in substrate and various measures of road impact. 

Watersheds with roads in use had higher percentages of fine sediment than those 

without roads and those with decommissioned roads. Watersheds with high 

levels of vegetative regrowth on decommissioned roadbeds had a lower 

percentage of fines in stream sediment. There were no statistically significant 

differences in the number of pools per 100 m or maximum pool depth among 

three treatment groups.

McNabb, D. H. 1994. Tillage of compacted 

haul roads and landings in the boreal forests of 

Alberta, Canada. For. Ecol. Manag. 66(1–3):

179–194.

Tillage of compacted haul roads and landings. Tillage significantly reduced mean 

bulk soil density. Minimizing the area in degraded soil, fracturing compacted soil 

(regardless of the method) to increase frost action, and spreading displaced soil is 

the most promising combination of treatments for protecting and rehabilitating 

degraded soils in the boreal forest.

Scully, R. J., E. J. Leitzinger, et al. 1990. Idaho 

habitat evaluation for off-site mitigation 

record. 1988 Annual Report to Bonneville 

Power Administration. U.S. Dept. Energy, 

BPA, Portland, OR.

Section of a large report. Steelhead and Chinook salmon. Based on Rosgen’s 

(1985) channel classifications: B channels have less pool and run habitat and 

much more pocket water than C channels, but both have similar mean widths and 

depths. B channels have a gradient less than 1.5% while C channels have 

gradients greater than 1.5%. B channels average 28% boulders, compared to 4% 

in C channels. Mean annual steelhead parr densities ranged 2–3 times greater in 

B channels than C channels (6.1/100 m2 vs. 2.5/100 m2

). Mean Chinook parr 

density was lowest (14.1/100 m2) in C channel streams where percent sand was 

less than 10%, and highest in the 10–20% sand interval with density declining for 

each 10% increase in percent sand above 20%.

Switalski, T. A., J. A. Bissonette, et al. 2004. 

Benefits and impacts of road removal. Front.

Ecol. Environ. 2(1):21–28.

Literature review. Long-term monitoring and initial research show that road 

removal reduces chronic erosion and the risk of landslides. Sediment loss on 

treated and untreated roads from seven studies indicate that mean erosion rates on 

treated roads range from 27 to 97 m3

/km compared to 115 to 235m3/km.
147

Wildlands CPR. 2012. Road reclamation: 

Measuring success. The Road RIPorter, 

Autumn Equinox 2012:3–10.

No fish. Using GRAIP (the Geomorphic Roads Analysis and Inventory 

Package). Decommissioned roads and stormproofing roads. For 

decommissioned roads, road-stream hydrologic connectivity was −58%, fine 

sediment delivery was −64%, drainpoint problem rate was −86%, and unit 

sediment was −64%. For stormproofed roads, road-stream hydrologic 

connectivity was −9%, fine sediment delivery was −119%, drainpoint problem 

rate was −48%, and unit sediment was −1.4%.

Wright, D. L., and R. E. Blaser. 1990. 

Establishment of vegetation on graded road 

cuts as influenced by topsoiling and tillage. 

West. J. Appl. For. 5(4):419–422.

Effects of grading and tillage on road cuts. Bulk density of smooth or roughened 

topsoil or subsoil ranged from 1.38 to 1.42, compared to 1.76 g/cm3 on 

compacted smooth subsoil. Total porosity was increased from 22% to 42% by 

roughening. The altered physical properties from roughening increased plant 

growth by increasing soil moisture content 23% and decreased soil temperature.

Acquisition and Protection Reference (Subtotal is 1 of 409)

Reference Key Quantitative Findings

Tetra Tech. 2013. Reach-scale effectiveness 

monitoring program. 2012 annual progress 

report. Tetra Tech EC Inc., Bothell, WA. 

Online at http://www.rco.wa.gov/documents/

monitoring/2012Report.pdf [accessed 01 

November 2013].

Evaluated the ecological condition of 10 habitat protection projects implemented 

across Washington state over an 8-year period. Looked at 21 indicators of upland 

and riparian vegetation, instream habitat, and fish and macroinvertebrate metrics. 

Projects have shown significant improvements in several of the upland vegetation 

indicators, including nonnative herbaceous absolute cover, nonnative herbaceous 

relative cover, and coniferous basal area, but no significant change for other 

indicators. Most notably, significant results were not found for any of the fish or 

riparian indicators in Year 8. The Index of Biotic Integrity scores for most 

projects were in the good range for macroinvertebrates and fish, though scores 

have been decreasing with time (i.e., the average score decreased from 90 to 89 to 

74 in years 0, 3, and 8, respectively). Note that they also reported on ongoing 

monitoring of instream and floodplain enhancement projects.
148

Flow References (Subtotal is 15 of 409)

Reference Key Quantitative Findings

Bednarek, A. T., and D. D. Hart. 2005. 

Modifying dam operations to restore rivers: 

Ecological responses to Tennessee River dam 

mitigation. Ecol. Appl. 15:997–1008.

Dissolved oxygen increased from 4.7 to 7.1 mg/L (34%), temperature decreased 

from 16.1 to 13.3, velocity increased 1.5 times (59%), discharge increased 528%, 

invertebrate family richness increased 36%, percent pollution tolerant taxa 13%, 

and total abundance increased 163% when flow increased, but decreased 60% 

with DO modifications. Note there were two treatments: increase in flow, and 

increase in DO following flow increase.

Dominick, D. S., and M. P. O’Neill. 1998. 

Effects of flow augmentation on stream 

channel morphology and riparian vegetation: 

Upper Arkansas River basin, Colorado. 

Wetlands 18(4):591–607.

Comparison of natural streams to streams where they augmented flow: increase in 

bankfull width and width/depth ratio in augmented streams; median particle size 

in augmented streams ranged from 38 to 56 mm, while it was 15 to 26 mm in 

natural basins; and augmented basins saw a decrease in riparian cover of up to 

10%. Note this study differs from others in that flow was diverted into streams to 

increase flows above natural.

Dyer, F. J., and M. C. Thoms. 2006. Managing 

river flows for hydraulic diversity: An 

example of an upland regulated gravel-bed 

river. River Res. Appl. 22:257–267.

Examined a variety of flows releases in an Australian river; results are not clear 

cut because of long reaches surveyed and multiple scales. The diversity of flow 

types or hydraulic patches changed with discharge, but changes observed did not 

follow a predictable or expected relationship. Note that results probably are not 

applicable to other streams.

Galat, D. L., L. H. Fredrickson, et al. 1998. 

Flooding to restore connectivity of regulated, 

large-river wetlands. Bioscience 48(9):721–

733.

Examines use of reconnected floodplain habitats following a series of large floods 

in Missouri River. Not a lot of quantitative results: twice as many fish species in 

reconnected habitats and more diverse riverine fish assemblages, differences in 

turtle species using connected vs. isolated habitats.

Hill, M. T., and W. S. Platts. 1998. Ecosystem 

restoration: A case study in the Owens River 

gorge, California. Fisheries 23(11):18–27.

Restoration of flows and flood pulsed to dewatered reach. Increased pulse and 

base flows led to establishment and rapid growth of riparian vegetation and good 

quality microhabitat (pools, runs, depth, and wetted width). Brown trout numbers

increased 40% and catch rates increased from 0/hour to 5.8–7.1 fish/hour.
149

Johansson, M. E., and C. Nilsson. 2002. 

Responses of riparian plants to flooding in 

free-flowing and regulated boreal rivers: An 

experimental study. J. Appl. Ecol. 39(6):971–

986.

Compared riparian vegetation on free flowing and regulated rivers. Growth rates 

of Betula pubescens and Filipendula ulmaira were higher in free flowing, while 

no difference was found for Carex acuta and Leontodon autumnalis.

Jurajda, P., M. Ondrackova, et al. 2004. 

Managed flooding as a tool for supporting 

natural fish reproduction in man-made lentic 

water bodies. Fish. Manag. Ecol. 11(3–4):

237–242.

Managed flooding of former borrow pits to examine effect on species diversity. 

Species richness was higher in flooded than nonflooded borrow pits (14.7 vs. 11). 

Adult fish abundance (catch per unit effort) was three to 14 times higher in 

flooded vs. nonflooded pits and juvenile abundance was nearly two times higher 

in flooded vs. nonflooded.

Rood, S. B., C. R. Gourley, et al. 2003. Flows 

for floodplain forests: A successful riparian 

restoration. Bioscience 53(7):647–656.

Restoration of flows to Truckee River led to recovery of cottonwood and sandbar 

willow, also led to return of 10 of 19 bird species that had been extirpated.

Increased spring and summer flows produced a tenfold increase in the adult cui-ui 

sucker (Chasmistes cujus) population.

Rood, S. B., and J. M. Mahoney. 2000. Revised 

instream flow regulation enables cottonwood 

recruitment along the St. Mary River, Alberta, 

Canada. Rivers 7(2):109–125.

Recruitment of cottonwood in a regulated river following natural and restored 

floods. High cottonwood recruitment following 1995 flood (seedling density 

200/m2

), but uncertain whether full recovery will occur as imposed base and 

flood flows may not reach those seen in natural floods (1995).

Sabaton, C., Y. Souchon, et al. 2008. Longterm brown trout population responses to flow 

manipulation. River Res. Appl. 24(5):476–

505.

Brown trout. Flow manipulation. On average, the potential habitat in bypass 

sections increased by 39% (a factor of 1.4 between the two flow levels). Average

weighted usable area was 68% of the maximum before enhancement and rose to 

87% postenhancement. For all bypass section sites, there was a 22.8% mean 

increase in the numbers of adults in the postenhancement period, as opposed to 

preincrease.

Scruton, D. A., T. C. Anderson, et al. 1998. 

Pamehac Brook: A case study of the 

restoration of a Newfoundland, Canada, river 

impacted by flow diversion for pulp 

transportation. Aquat. Conserv.: Mar. Freshw. 

Ecosyst. 8(1):145–157.

Restoration of flows to dewatered stream. Before and after monitoring indicated 

an increase in fluvial habitat to 450 units, a 62% increase. Salmonid production 

(Atlantic salmon and brook trout) was estimated to increase eighteenfold. 

Biomass increased from 68.4 g/unit to 281 g/unit or total production from 18 kg 

to 330 kg.
150

Speierl, T., K. H. Hoffmann, et al. 2002. 

Fischfauna und habitatdiversität: Die 

auswirkungen von renaturierungsmabnahmen 

an Main und Rodach. [Fish communities and 

habitat diversity: The effect of river 

restoration measures on the Main and 

Rodach.] Natur und Landschaft Stuttgart 

77(4):161–171.

In German; key quantitative findings listed here are based on the English abstract 

only. Restored reaches vs. regulated reaches. More species and individuals were 

caught in restored vs. regulated for larvae, juvenile, and adult fishes. No details.

Stevens, L. E., T. J. Ayers, et al. 2001. Planned 

flooding and Colorado River riparian tradeoffs downstream from Glen Canyon Dam, 

Arizona. Ecol. Appl. 11(3):701–710.

Test flood in Colorado River: restored sandbars, 10.7% of endangered snail 

habitat and 7% of population was lost, buried riparian vegetation under greater 

than 1 m of sand.

Theiling, C. H., J. K. Tucker, et al. 1999. 

Flooding and fish diversity in a reclaimed 

river-wetland. J. Freshw. Ecol. 14(4):469–

475.

Studied response of reclaimed river wetland to flooding: eight species found prior 

to flooding vs. 26 species afterward. Thirty-three species were found the 

following June, but only 16 in subsequent collections in August, suggesting 

temporary or seasonal increases in diversity due to flooding.

Weisberg, S. B., and W. H. Burton. 1993. 

Enhancement of fish feeding and growth after 

an increase in minimum flow below the 

Conowingo Dam. N. Am. J. Fish. Manag. 

13:103–109.

Diversity of consumed prey increased from 143 to 186 species for white perch, 

but not channel catfish or yellow perch. Growth rate of white perch increased by 

as much as 38%. Condition factor of all three species was greater after treatment.
Appendix B: Subset of the Literature Examined 

that Reported on Survival

Table B-1. Key findings from a subset of papers on restoration effectiveness in Appendix A that reported 

survival or changes in survival due to restoration. Off-channel/floodplain treatment projects are 

listed first (the first five references, in alphabetical order by author), followed by instream habitat 

treatment projects (the next 14 references, in alphabetical order by author).

Reference

Treatment

and location Key survival results

Cederholm, C. J., and N. P. Peterson.

1989. A summary comparison of two 

types of winter habitat enhancement for 

juvenile coho salmon (Oncorhynchus 

kisutch) in the Clearwater River,

Washington. In B. G. Shepherd (ed.), 

Proceedings of the 1988 Northeast 

Pacific Chinook and Coho Salmon 

Workshop, p. 227–239. Ministry of 

Environment, Penticton, BC.

Constructed 

floodplain 

habitat in 

Washington

Significant increase in winter coho 

salmon overwinter survival (rate = .57).

Cederholm, C. J., W. J. Scarlett, et al. 

1988. Low-cost enhancement technique 

for winter habitat of juvenile coho 

salmon. N. Am. J. Fish. Manag. 8:438–

441.

Constructed 

floodplain 

habitat in 

Washington

Overwinter survival and growth of coho 

salmon increased significantly after

construction (survival .11 to .56, mean 

change in length from 13 to 41 mm,

mean change in weight from 3 to 13 g).

Henning, J. A., R. E. Gresswell, et al. 

2006. Juvenile salmonid use of 

freshwater emergent wetlands in the 

floodplain and its implications for 

conservation management. N. Am. J. 

Fish. Manag. 26:367–376.

Reconnected 

wetland in 

Washington

Yearling coho salmon had comparable 

specific growth rate and minimum 

estimates of survival (1.43%/d by weight 

and 30%; 1.37%/d and 57%) to other 

side channel rearing studies.

Raastad, J. E., A. Lillehammer, et al. 

1993. Effect of habitat improvement on 

Atlantic salmon in the regulated River 

Suldalslagen. Regul. Rivers: Res. 

Manag. 8(1–2):95–102.

Constructed 

side channel 

in Norway

Survival of age-1+ Atlantic salmon was 

30%.

Sommer, T. R., M. L. Nobriga, et al. 

2001b. Floodplain rearing of juvenile 

Chinook salmon: Evidence of enhanced 

growth and survival. Can. J. Fish. Aquat. 

Sci. 58(2):325–333.

Levee 

removal in 

California

Survival indices for coded-wire-tagged 

Chinook salmon were somewhat higher 

for those released in the floodplain than 

for those released in the river, but the 

differences were not statistically

significant.

151
Table B-1 continued. Key findings from a subset of papers on restoration effectiveness in Appendix A 

that reported survival or changes in survival due to restoration. Off-channel/floodplain treatment 

projects are listed first (the first five references, in alphabetical order by author), followed by 

instream habitat treatment projects (the next 14 references, in alphabetical order by author).

Reference

Treatment

and location Key survival results

Gard, R. 1961. Creation of trout habitat 

by constructing small dams. J. Wildl. 

Manag. 52(4):384–390.

Large woody 

debris 

(LWD) and 

boulder

structures in 

California

During the three summers following 

dam installation, the numbers of 

introduced brook trout were counted. 

Forty-nine trout were collected the 

second summer, yielding a 1-year 

survival rate of 38%. Seventy-three 

percent of the fish surviving to the 

second summer were collected the third

summer and 39% of those surviving to 

the third summer lived to the fourth.

Giannico, G. R., and S. G. Hinch. 2003. 

The effect of wood and temperature on 

juvenile coho salmon winter movement, 

growth, density, and survival in side 

channels. River Res. Appl. 19(3):219–

231.

LWD 

additions in 

BC, Canada

Although the values of the relative index 

of survival for juvenile coho salmon 

varied widely between both side 

channels and from year to year, they 

were consistently higher in the woodtreated side.

Gowan, C., and K. D. Fausch. 1996a. 

Long-term demographic responses of 

trout populations to habitat manipulations 

in six Colorado streams. Ecol. Appl. 

6:931–946.

LWD 

additions in 

Colorado

Recaptures of tagged trout and batchmarked trout revealed that immigration 

was primarily responsible for increased 

adult abundance and biomass, whereas 

no biologically significant differences 

occurred for recruitment, survival, or 

growth.

Jester, D. B., and H. J. McKirdy. 1966. 

Evaluation of trout stream improvement 

in New Mexico. Proc. Annu. Conf. 

Western Assoc. State Game Fish Comm. 

46:316–333.

LWD and

boulder 

structures in 

New Mexico

Trout overwinter survival was enhanced 

by the presence of structures.

Johnson, S. L., J. D. Rodgers, et al. 2005. 

Effects of an increase in large wood on 

abundance and survival of juvenile 

salmonids (Oncorhynchus spp.) in an 

Oregon coastal stream. Can. J. Fish. 

Aquat. Sci. 62(2):412–424.

LWD 

additions in 

Oregon

Steelhead smolt abundance, steelhead 

freshwater survival, and coho salmon 

freshwater survival increased in one 

creek after the input of wood, but similar 

results were found in the reference 

stream.

Klassen, H. D., and T. G. Northcote. 1988. 

Use of gabion weirs to improve spawning 

habitat for pink salmon in a small logged 

watershed. N. Am. J. Fish. Manag. 

8(1):36–44.

Rock 

structures 

(gabions) in 

BC, Canada

Pink salmon egg survival at one site in 

its first year did not differ significantly 

from two nearby reference sites.

152
Table B-1 continued. Key findings from a subset of papers on restoration effectiveness in Appendix A 

that reported survival or changes in survival due to restoration. Off-channel/floodplain treatment 

projects are listed first (the first five references, in alphabetical order by author), followed by 

instream habitat treatment projects (the next 14 references, in alphabetical order by author).

Reference

Treatment

and location Key survival results

Lonzarich, D. G., and T. P. Quinn. 1995. 

Experimental evidence for the effect of 

depth and structure on the distribution, 

growth, and survival of stream fishes. 

Can. J. Zool. 73:2223–2230.

LWD 

additions in 

Washington

Coho salmon survival was greatest in the 

deep, structured treatment (89%), nearly 

twice that in the shallow, nonstructured

treatment (47%). Both age-0 and age-1+ 

steelhead showed higher survival in the 

deep, structured treatment (71% and 

89%) than in the shallow, nonstructured

treatment (29% and 33%, respectively).

Merz, J. E., J. D. Setka, et al. 2004. 

Predicting benefits of spawning-habitat 

rehabilitation to salmonid (Oncorhynchus

spp.) fry production in a regulated 

California river. Can. J. Fish. Aquat. Sci. 

61(8):1433–1446.

Gravel 

additions in 

California

Chinook salmon embryos planted in 

enhanced gravels had higher rates of 

survival to the swim-up stage than 

embryos planted in unenhanced 

spawning gravels.

Overton, K., W. A. Brock, et al. 1981. 

Restoration and enhancement program of 

anadromous fish habitat and populations 

on Six Rivers National Forest. In T. J. 

Hassler (ed.), Proceedings: Propagation, 

Enhancement, and Rehabilitation of 

Anadromous Salmonid Populations and 

Habitat in the Pacific Northwest 

Symposium, p. 158–168. Humboldt 

State Univ., Arcata, CA.

Boulder 

stuctures in 

California

Steelhead egg-to-fry survival ranged 

from 71% to 98%. Not clear how this 

compared to unrestored areas.

Paulsen, C. M., and T. R. Fisher. 2005. 

Do habitat actions affect juvenile 

survival? An information-theoretic 

approach applied to endangered Snake 

River Chinook salmon. Trans. Am. Fish. 

Soc. 134(1):68–85.

Various in 

Idaho

There was a positive, significant 

correlation between the number of 

habitat actions in a basin and Chinook 

salmon parr-to-smolt survival.

Pulg, U., B. T. Barlaup, et al. 2013. 

Restoration of spawning habitats of 

brown trout (Salmo trutta) in a regulated 

chalk stream. River Res. Appl. 

29(2):172–182.

Gravel 

cleaning in 

Germany

In the first 2 years, highly suitable 

conditions were maintained, with a 

potential brown trout egg survival of 

more than 50%. Afterward, the sites 

offered moderate conditions, indicating 

an egg survival of less than 50%.

153
Table B-1 continued. Key findings from a subset of papers on restoration effectiveness in Appendix A 

that reported survival or changes in survival due to restoration. Off-channel/floodplain treatment 

projects are listed first (the first five references, in alphabetical order by author), followed by 

instream habitat treatment projects (the next 14 references, in alphabetical order by author).

Reference

Treatment

and location Key survival results

Riley, S. C., and K. D. Fausch. 1995. 

Trout population response to habitat 

enhancement in six northern Colorado 

streams. Can. J. Fish. Aquat. Sci. 52:

34–53.

LWD 

structures in 

Colorado

Recaptures of tagged trout in two 

streams showed that the logs did not 

result in increased growth or survival of 

resident trout, although recaptures of finclipped trout in other streams suggested 

that apparent survival may have 

increased temporarily in treatment 

sections.

Rodgers, J. D., S. L. Johnson, et al. 1993. 

The seasonal use of natural and 

constructed habitat by juvenile coho 

salmon (Oncorhynchus kisutch) and 

preliminary results from two habitat 

improvement projects on smolt 

production in Oregon coastal streams. 

In L. Berg and P. W. Delaney (eds.), 

Proceedings of the coho workshop, 

Nanaimo, BC, May 26–28, 1992, p. 334–

351. DFO Canada, Vancouver, BC.

LWD 

additions in 

Oregon

Average coho salmon overwinter 

survival increased from 11% in one 

creek to 51% the first year, and 40% the 

second year after treatment. In another 

creek, it increased from 14% to 63% in 

the first year.

Solazzi, M. F., T. E. Nickelson, et al. 

2000. Effects of increasing winter 

rearing habitat on abundance of 

salmonids in two coastal Oregon streams. 

Can. J. Fish. Aquat. Sci. 57:906–914.

LWD 

additions in 

Oregon

Overwinter survival of coho salmon 

increased from a mean of .13 to .38 

(reference was .17 to .20). In another 

stream, mean overwinter survival 

increased 250% from .11 to .39, but fell

in the reference stream from .19 to .10.

154
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