EPA910-R-07-005
United States
Environmental Protection
Agency
Region 10
1200 Sixth Avenue
Seattle WA 98101
Alaska
Idaho
Oregon
Washington
Office of Environmental Assessment
December 2007
Ecological Condition of
Wadeable Streams of the
Interior Columbia Basin
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Ecological Condition of Wadeable Streams of the
Interior Columbia River Basin
An EPA Environmental Monitoring and Assessment Program Report
Authors:
Lillian G. Herger, Gretchen A. Hayslip, and Peter T. Leinenbach
December 2007
U.S. Environmental Protection Agency, Region 10
Office of Environmental Assessment
1200 Sixth Avenue
Seattle, Washington 98101
Publication Number: EPA 910-R-07-005
Suggested Citation:
Herger, L.G., G.A. Hayslip, and P.T. Leinenbach. 2007. Ecological Condition of Wadeable
Streams of the Interior Columbia River Basin. EPA-910-R-07-005. U.S. Environmental
Protection Agency, Region 10, Seattle, Washington.
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Table of Contents
TABLE OF CONTENTS II
LIST OF FIGURES Ill
LIST OF TABLES IV
LIST OF MAPS IV
ACKNOWLEDGEMENTS V
ABSTRACT 1
PURPOSE 1
INTRODUCTION 1
EMAP WESTERN PILOT 2
THE INTERIOR COLUMBIA BASIN 3
Ecological Regions 3
Land Management. 6
DESCRIPTION OF ECOLOGICAL ASSESSMENT 6
SURVEY DESIGN 6
ECOLOGICAL INDICATORS 7
Aquatic Stressor Indicators 7
Setting Expectations 8
METHODS 8
QUALITY ASSURANCE 8
SITE SELECTION 9
Reference Site Dataset 10
FIELD AND LABORATORY METHODS 10
Water Quality 10
Physical Habitat 10
Vertebrates 11
Benthic Invertebrates 11
Landscape Data 11
ANALYSIS METHODS 12
Reference Condition Methods 12
CITATIONS 41
APPENDICES 48
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List of Figures
Figure 1. Example of watershed in relation to atypical sample reach 11
Figure 2. Example of a hypothetical CDF showing a threshold between impaired and full support 13
Figure 3. Fate of sites targeted for sampling following site evaluation 16
Figure 4. Percent of the total stream length in each Strahler stream order (stream length=74,976km) 16
Figure 5. The proportion of target stream length in each State (total length=74,976km) 16
Figure 6. Proportion of target stream length represented in the 3 aggregate ecoregion 17
Figure 7. Distribution of land cover types in the watersheds of wadeable streams of the Interior Columbia Basin 18
Figure 8. Presence of substrate particle size classes (stream length= 74,976) 18
Figure 9. Distribution of native and alien vertebrate richness metrics within the target stream length 19
Figure 10. Extent of vertebrate families present in wadeable streams of the Basin 20
Figure 11. Extent of most common fish species in the Basin (n=124, stream length=45,006 km) 21
Figure 12. Species presence of amphibians in the Basin (n=124, stream length=45,006 km) 21
Figure 13. CDF of number of EPT taxa (stream length =74,976 km) 22
Figure 14. CDF of percent of taxa that are EPT (stream length=74,976 km) 22
Figure 15. CDF of observed to expected macroinvertebrate taxa presence with thresholds for poor-fair-good condition
(stream length=74,976 km) 23
Figure 16. Proportion of stream length in poor-fair-good condition based on O/E score for aggregated ecoregions.... 23
Figure 17. CDF of sulfate (stream length=74,976 km) 24
Figure 18. CDF of chloride (stream length=74,976 km) 24
Figure 19. CDF of phosphorous (stream length=74,976 km) 25
Figure 20. CDF of total nitrogen (stream length= 74976 km) 25
Figure 21. CDF of pH (stream length= 74976 km) 26
Figure 22. CDF of conductivity (stream length =74,976 km) 26
Figure 23. CDF of riparian vegetation presence (stream length=74,976 km) 27
Figure 24. CDF of human disturbance in the riparian zone (stream length =74,976 km) 28
Figure 25. CDF of canopy density measured at mid-channel (stream length=74,390 km) 28
Figure 26. CDF of loglO of the relative bed stability (stream length=64,280 km) 29
ill
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Figure 27. CDF of large woody debris volume (stream length=74,976 km) 29
Figure 28. CDF of fish cover (stream length=74,976 km) 30
Figure 29. CDF of pool and glide habitat types, (stream length=74,159 km) 30
Figure 30. CDF of percent sand and fine ubstrate <2mm diameter (stream length=74,976 km) 32
Figure 31. CDF of streambed substrate embeddedness (stream length=74,976 km) 32
Figure 32. CDF of total suspended solids (stream length=73,758 km) 33
Figure 33. Extent of stream length in poor (red), fair (orange), and good (blue) condition for selected water
quality indicators 34
Figure 34. Extent of stream length in poor-fair-good condition for selected physical habitat indicators 34
Figure 35. Extent of stream length in poor - fair- good condition for selected physical habitat indicators 35
Figure 3 6. Extent of stream length in poor -fair- good condition for sediment indicators 36
Figure 37. Risk to benthic assemblage (taxa loss) relative to the environmental stressor condition 37
Figure 38. Summary of extent of stressors in poor condition in relation to relative risk 38
List of Tables
Table 1. The number of reference sites by ecoregion and combined ecoregions 12
Table 2. Ecological condition metrics calculated with data for both reference and probability sites 12
Table 3. Vertebrate presence in the Basin (n=124 sites, stream length=45,006 km) 19
List of Maps
Map 1. Level III ecoregions of the Interior Columbia Basin (USEPA 2003) 3
Map 2. Sample locations of probability and reference sites 9
IV
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Acknowledgements
This project was completed with the help of numerous individuals and agencies. EMAP field
data were collected by state environmental monitoring departments including Idaho DEQ,
Oregon DEQ, Montana DEQ, Utah DWQ, Washington Ecology, and USGS in Wyoming. Data
management including quality assurance, metric calculations (including Observed/Expected
scores), and electronic conversion were provided by USEPA Office of Research and
Development (Corvallis, OR). ORD scientists also provided guidance in the development of
relative risk calculations and technical support. We particularly thank the following cooperators:
Tony Olsen, David Peck, and John Van Sickle, and Phil Kaufmann (EPA, Office of Research
and Development, Corvallis, OR).
Bob Hughes and Alan Herlihy, Oregon State University
Shannon Hubler, Oregon Department of Environmental Quality
Glenn Merritt, Washington Department of Ecology
Mary Anne Nelson-Kosterman, Idaho Department of Environmental Quality
The quality of the report was improved by comments from several reviewers: Lorraine Edmond
(EPA Region 10), Glenn Merritt (Washington Ecology), and David Peck (EPA, Office of
Research and Development, Corvallis, OR).
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Abstract
The Environmental Monitoring and Assessment Program (EMAP) was developed by EPA to
assess the condition of the nation's ecological resources. EMAP employs a statistical design that
makes it possible to describe the proportion of the resource in good, fair or poor condition
relative to reference condition. In 2000, the EMAP began a five-year effort to monitor and
assess the ecological condition of rivers and streams across the West. This report uses a subset
of the data from this large project and data from other EMAP projects to assess the ecological
condition of the wadeable streams of the Interior Columbia River basin. Approximately 75,000
km of the 109,000 km of wadeable streams of the Basin were assessed for most indicators. In
general, most streams of the basin are in fair or good condition based on the results of the metrics
that could be analyzed. Primary stressors in terms of both extent and risk to biota are excess fine
sediment, riparian disturbance from grazing/crops, sulfate, and phosphorous levels.
Purpose
This ecological assessment of the Interior Columbia River Basin has three purposes:
Report on the ecological condition of wadeable streams of the Interior Columbia Basin
using direct measures of biological assemblages.
Identify and rank the relative importance of potential stressors affecting stream condition by
using supplemental measures of chemical, physical and biological habitat to answer the
following questions:
How wide-spread/common are these stressors?
What is the "risk" to stream biota related to these stressors?
Demonstrate the usefulness of the EMAP- type study design and analysis for assessing regional
waterbody condition, which could potentially be implemented as part of state surface waters
monitoring programs.
Introduction
EMAP (Environmental Monitoring and Assessment Program) was initiated by EPA to estimate
the status and trends of the nation's ecological resources and examine associations between
ecological condition and natural and anthropogenic influences. The surface water component of
EMAP is based on the premise that the condition of stream biota can be addressed by examining
biological and ecological indicators of stress. The long-term goal of EMAP is to develop
ecological methods and procedures that permit the measurement of environmental resources to
determine if they are in an acceptable or unacceptable condition relative to a set of
environmental or ecological values. Two major features of EMAP are the use of ecological
indicators and probability-based selection of sample sites.
We use the EMAP data collected as part of EPA's Westwide pilot project to assess the biotic
condition by focusing on the direct measurements of the biota in relation to the physical and
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EPA Region 10, Office of Environmental Assessment
chemical condition through the use of biological indicators. This approach utilizes the fact
thattream biota integrate many of the physical and chemical stressors and other biota (such as
non-native species) that affect the aquatic ecosystem in which they reside.
An Ecological Assessment can be performed in a variety of ways such as a description of the
extent of a resource or an enumeration of the abundance and distribution of biota in an
ecosystem. This Ecological Assessment of the Interior Columbia Basin evaluates two critical
components of aquatic ecosystems: 1) the condition of the biota, and 2) the relative importance
of human-caused stressors.
The first component of this ecological assessment is based on the fact that biological
communities are adapted to local habitat (the combination of physical, chemical, and spatial
elements) and therefore the ecological condition of wadeable streams is reflected by the
quality/health of the biotic communities. In other words, the biotic communities integrate the
many human disturbances that we are interested in assessing. Maintaining the biotic
communities is also one of the pillars of the Clean Water Act ".... Supporting and maintaining a
balanced, integrated, adaptive community of organisms having a species composition, diversity,
and functional organization comparable to that of the natural habitat."
The second component of this ecological assessment evaluates ecological stressors. Stressors
are defined as the pressures or disturbances exerted on aquatic systems. These are the chemical,
physical, and biological components of the ecosystem that have the potential to degrade the
biotic integrity of the aquatic system. This ecological assessment will identify stressors and
describe their extent as well as their relative importance in terms of risk to the biotic integrity of
the Interior Columbia Basin wadeable streams.
EMAP Western Pilot
The EMAP Western Pilot was a five-year effort to collect data across the twelve western states
and to report on the ecological condition of this area (Stoddard et al. 2005a and Stoddard et al.
2005b). Consistent field, lab, and data analytical methods were used across the area and across
stream types. All sites were selected using a probabilistic design. Collectively, the sites are a
statistical representation of the target population of flowing waters of the western states.
This report uses data collected as part of the Western Pilot. The Interior Columbia was selected
by Region 10 as the study area because:
The Columbia River is one of the seven Region 10 Strategic Planning Priorities.
The basin comprises a major portion of the Region 10 geographical range.
Region 10 has previously reported on stream condition in other major portions of the
Region using EMAP data (Hay slip et al. 2004, Herger et al. 2003, Hay slip et al. 2001,
and Herger et al. 2000). This is the first time extensive data have been available for
reporting on the ecological condition of streams in this area.
Additional EMAP data were available from other regional EMAP projects in whole or in part
conducted within the Interior Columbia Basin. These additional data provide the opportunity to
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refine the 'quality thresholds' for the analysis of the Interior Columbia Basin and generate a
more robust analysis than we have previously been able to conduct using EMAP data.
The Interior Columbia Basin
The Columbia River is the second largest river in the United States based on discharge. The U.S.
portion of the Columbia River Basin encompasses almost all of Idaho, large portions of
Washington and Oregon, and small areas of Montana, Utah, Wyoming, and Nevada (Map 1).
The basin is 202,705 square miles in area (slightly smaller than France). The Columbia River
originates in Canada and drains south through Washington State. Major tributary rivers include
the Snake and Clearwater rivers which originate in Idaho and drain to the west and the Deschutes
and John Day rivers which originate in Oregon and drain to the north.
Map 1. Level III ecoregions of the Interior Columbia Basin (USEPA 2003a).
Ecological Regions
The Columbia River Basin ecosystem has diverse physiological, climatic, and floral and faunal
characteristics as evident by the inclusion of all or portions of 11 different ecological regions
(ecoregions) within its boundary (USEPA 2003a). Ecoregions are areas that are relatively
homogenous with respect to ecological systems (Omernik 1995). The diversity of the UCB
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includes large expanses of high xeric plateau, steep mountains, and extensive forested areas. The
basin has two major climatic regions, xeric and mountainous areas. The xeric portion of the
basin is represented by the aggregation of the Columbia Plateau, North Basin Range, and Snake
River Plain ecoregions. The aggregates of the remaining ecoregions comprise the mountainous
climatic region. The following are brief descriptions of the Level III Ecoregions of the Basin
shown on Map 1 (excerpts from Bryce 1997).
Blue Mountains (1): This ecoregion is distinct from the neighboring Cascades and Northern
Rockies ecoregions because the Blue Mountains are generally not as high and are considerably
more open. Like the Cascades, but unlike the Northern Rockies, the region is mostly volcanic in
origin. Only the few higher ranges, particularly the Wallowa and Elkhorn Mountains, consist of
intrusive rocks that rise above the dissected lava surface of the region. Unlike the bulk of the
Cascades and Northern Rockies, much of this ecoregion is grazed by cattle.
Cascades (4): This mountainous ecoregion is underlain by Cenozoic volcanics and has been
affected by alpine glaciations. It is characterized by steep ridges and river valleys in the west, a
high plateau in the east, and both active and dormant volcanoes. Elevations range up to 4,390
meters. Its moist, temperate climate supports an extensive and highly productive coniferous
forest. Subalpine meadows occur at high elevations.
Eastern Cascade Slopes and Foothills (9): The Eastern Cascade Slopes and Foothills ecoregion is
in the rain-shadow of the Cascade Mountains. Its climate exhibits greater temperature extremes
and less precipitation than ecoregions to the west. Open forests of ponderosa pine and some
lodgepole pine distinguish this region from the higher ecoregions to the west where fir and
hemlock forests are common, and the lower drier ecoregions to the east where shrubs and
grasslands are predominant. The vegetation is adapted to the prevailing dry continental climate
and is highly susceptible to wildfire. Volcanic cones and buttes are common in much of the
region.
Columbia Plateau (10): The Columbia Plateau is an arid sagebrush steppe and grassland, which
is surrounded by moister, predominantly forested, mountainous ecological regions. This region is
underlain by basalt up to two miles thick. It is covered in some places by loess soils that have
been extensively cultivated for wheat, particularly in the eastern portions of the region where
precipitation amounts are higher.
Snake River Plain (12): This portion of the xeric intermontane basin and range area of the
western United States is considerably lower and more gently sloping than the surrounding
ecoregions. Mostly because of the available water for irrigation, a large percent of the alluvial
valleys bordering the Snake River are in agriculture, with sugar beets, potatoes, and vegetables
being the principal crops. Cattle feedlots and dairy operations are also common in the river plain.
Except for the scattered barren lava fields, the rest of the plains and low hills in the ecoregion are
characterized by sagebrush steppe vegetation. The natural vegetation is now used for cattle
grazing.
Northern Rockies (15): The high, rugged Northern Rockies ecoregion is mountainous and lies
east of the Cascades. Despite its inland position, climate and vegetation are, typically, marine-
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influenced. Douglas fir, subalpine fir, Englemann spruce, and ponderosa pine and Pacific
indicators such as western red cedar, western hemlock, and grand fir are found in the ecoregion.
The vegetation mosaic is different from that of the Middle Rockies which is not dominated by
maritime species. The Northern Rockies ecoregion is not as high or as snow- and ice-covered as
the Canadian Rockies although alpine characteristics occur at highest elevations and include
numerous glacial lakes. The presence of granitics and associated management problems are less
extensive than in the Idaho Batholith.
Idaho Batholith (16): This ecoregion is a dissected, partially glaciated, mountainous plateau.
Many perennial streams originate here and water quality can be high if basins are undisturbed.
Deeply weathered, acidic, intrusive igneous rock is common and is far more extensive than in the
Northern Rockies or the Middle Rockies. Soils are sensitive to disturbance especially when
stabilizing vegetation is removed. Land uses include logging, grazing, and recreation. Mining
and related damage to aquatic habitat is widespread. Grand fir, Douglas-fir and, at higher
elevations, Engelmann spruce, and subalpine fir occur; ponderosa pine, shrubs, and grasses grow
in very deep canyons. Maritime influence lessens toward the south and is never as strong as in
the Northern Rockies.
Middle Rockies (17): The climate of the Middle Rockies lacks the strong maritime influence of
the Northern Rockies. Mountains have Douglas-fir, subalpine fir, and Engelmann spruce forests
and alpine areas; Pacific tree species are never dominant. Forests can be open. Foothills are
partly wooded or shrub- and grass-covered. Intermontane valleys are grass- and/or shrub-covered
and contain a mosaic of terrestrial and aquatic fauna that is distinct from the nearby mountains.
Many mountain-fed, perennial streams occur and differentiate the intermontane valleys from the
Northwestern Great Plains. Granitics and associated management problems are less extensive
than in the Idaho Batholith. Recreation, logging, mining, and summer livestock grazing are
common land uses.
Canadian Rockies (41): This ecoregion straddles the border between Alberta and British
Columbia in Canada and extends southeastward into northwestern Montana. The region is
generally higher and more ice-covered than the Northern Rockies. Vegetation is mostly Douglas
fir, spruce, and lodgepole pine at lower elevations and alpine fir at middle elevations. The higher
elevations are treeless alpine. A large part of the region is in national parks where tourism is the
major land use. Forestry and mining occur on the non-park lands.
North Cascades (77): The terrain of the North Cascades is composed of high, rugged mountains.
It contains the greatest concentration of active alpine glaciers in the conterminous United States
and has a variety of climatic zones. A dry continental climate occurs in the east and mild,
maritime, rainforest conditions are found in the west. It is underlain by sedimentary and
metamorphic rock in contrast to the adjoining Cascades which are composed of volcanics.
Northern Basin and Range (80): This ecoregion contains arid tablelands, intermontane basins,
dissected lava plains, and scattered mountains. Non-mountain areas have sagebrush steppe
vegetation; cool season grasses are more common than in the hotter-drier basins of the Central
Basin and Range which are dominated by sagebrush, shadscale, and greasewood. Rangelands are
generally covered in mountain sagebrush, mountain brush, and Idaho fescue at lower and mid-
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EPA Region 10, Office of Environmental Assessment
elevations; Douglas-fir, and aspen are common at higher elevations. Overall, the ecoregion is
drier and less suitable for agriculture than the Columbia Plateau and higher and cooler than the
Snake River Plain. Rangeland is common and dryland and irrigated agriculture occur in eastern
basins.
Land Management
As in the rest of the West, rapid population growth and competing uses for water are ongoing
management issues in the Interior Columbia basin. Water has always been the scarce resource
and agriculture, livestock grazing, and timber harvest are the primary land uses. Dominant land
cover types are forest (37%), shrublands (33%), and agriculture (13%) (Map 2). Urban land use
is sparse (<1%). Land ownership is mostly public. The basin includes large areas of interior
plains and plateaus with annual precipitation of 7-20 inches. Portions of the basin are
mountainous and the median elevation is 1354 m.
Description of Ecological Assessment
Survey Design
This ecological condition assessment is presented at the basin-wide scale. The main body of the
report describes ecological condition in terms of extent of and risk to the ecological resources for
the Interior Columbia Basin. The aquatic resource assessed in this report is the network of all
wadeable perennial streams within the Interior Columbia River Basin boundary (Map 1).
Assessing a very large and diverse basin requires a study design that can adequately capture the
variation across the landscape and be descriptive of the entire resource of wadeable streams.
There are various options for collecting the data in order to describe the ecological condition of
this target population. A census method, where data are collected from every stream, is
impractical (if not impossible). EMAP uses a sample survey approach (similar to a public
opinion poll) where data are collected from a subset of the streams. This information is then
used to determine summary characteristics of the 'target population'. A probability-based
sampling method is used to select sites that are statistically representative of the target
population. In a probability sample, every stream segment of the target population has a known,
non-zero probability of being selected. This feature has two advantages in that 1) it guards
against site selection bias and 2) it allows one to make scientifically valid inferences to
characteristics of the entire target population.
The target population was sampled in a spatially-restricted manner so that the distribution of the
sample sites has approximately the same spatial distribution as the target population. This is
achieved by using an unequal probability sample method to insure distribution of samples of
sites by stream size (Strahler order), State, and major ecoregion types (humid and arid). For
example, 3rd order streams had a four times higher probability of being selected than a 1st order
stream. This method effectively increases the probability of having 3rd order streams selected for
the sample so that the sample is not dominated by 1st order streams, which are much more
common. This variable selection probability by stream orders is accounted for when making the
regional estimates by using site weighting factors. Each site is assigned a weight, based on the
occurrence of its type in the stream database. First order streams have a smaller weighting factor
than higher order streams. Therefore, there is not a one-to-one relation of sample sites to the
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stream length each site represents, and any inferences based on the unweighted set of sites to the
entire target population would be inaccurate.
Ecological indicators
This analysis uses indicators to quantify both ecological condition (condition indicators) and
stressor condition (stressor indicators) (Hughes et al. 2000). Indicators are ecological
measurements, metrics, or indices that quantify physical, chemical, biological condition, habitat,
or stressors (Hughes 1993). Condition indicators used to quantify ecological condition are
developed from data on the various aquatic biological assemblages including benthic
macroinvertebrates, vertebrates (fish and amphibians) and periphyton. Each of these
assemblages has specific characteristics that make them useful for quantifying ecological
condition. Single metrics used to describe ecological condition include measures of overall
species richness, diversity measures such as the Shannon Index, or quantification of sensitive
taxa such as 'number of Ephemeroptera, Plecoptera, or Trichoptera taxa' (EPT taxa).
Multimetric indices are also used as ecological indicators (Barbour et al. 1995). These indices of
biological integrity (IBIs) incorporate various metrics of a particular aquatic assemblage into a
single metric. IBIs are commonly developed for benthic macroinvertebrate assemblages. IBIs
are robust as they incorporate various ecological aspects of the assemblage that are informative
of the overall condition of the assemblage such as species diversity and occurrence of tolerant
taxa.
The benthic macroinvertebrate assemblage was selected for assessing the relationship of
environmental condition to the response of the biological community. The macroinvertebrate
metric that provides an estimate of the taxa completeness, and therefore is a measure of the
'biotic quality', was the Observed to Expected macroinvertebrate taxa metric (O/E metric).
This metric describes the loss of macroinvertebrate biological diversity (Hawkins et al. 2000)
and is a direct measure of how many taxa are missing at a site. The Observed to Expected
macroinvertebrate taxa presence metric is the number of macroinvertebrate taxa observed in the
sample divided by the taxa that are expected to occur. This metric was selected for the analysis
because it could be calculated for all of the EMAP probability sample sites in the Basin as well
as the additional reference sites that were incorporated into the study. Data for the development
of IBIs for both vertebrates and invertebrates were either insufficient or not compatible across all
of the reference sites to be useable as a basin-wide aquatic condition indicator.
Aquatic Stressor Indicators
Ecological stressors are chemical, physical, and biological effects that are 'stressful' to the
aquatic ecosystem and have the potential to directly affect the stream biotic assemblages.
Stressor indicators can be directly measured either in the stream or in the riparian area. Direct
stressors are often the result of human alteration of land cover or the result of land management.
The data collected at the EMAP stream sites are used to generate hundreds of metrics that have
potential use as indicators of stress. This report examines the most relevant metrics for
indicating the stressors affecting the ecological condition. These metrics comprise a short list of
those which had adequate data both in the Interior Columbia EMAP probability data set and in
the reference site data, and where we were able to establish relations of quality across the
ecoregions. By comparing the data for specific stressor metrics between the reference sites and
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the probability sites by ecoregion we are able to establish the range of condition from good to
poor for these specific metrics. Besides being useful for quantifying the extent of ecological
stress, these metrics can be associated with the ecological condition established from the
condition indicators to assess ecological risk (the severity of stress on biological condition).
Stress indicators are presented in four categories: water chemistry, riparian zone, in-channel
habitat complexity, and sediment.
Setting Expectations
In order to describe the ecological condition of the wadeable streams of the Interior Columbia
Basin, we must have an expectation of the ecological condition in a relatively 'undisturbed' state.
This benchmark for determining ecological condition is commonly referred to as the reference
condition. A reference condition can have many meanings. For instance, it could mean a 'pre-
settlement condition', a 'desired condition', or an 'acceptable current condition' which implies
some level of human disturbance. Setting reasonable expectations for each of the indicators of
ecological condition is therefore a challenge. For this assessment, reference condition is
developed from the analysis of carefully selected sites that represent the best attainable (or least
disturbed) watershed condition, habitat structure, water quality and biological parameters
(Hughes 1995, Stoddard et al. 2006). Deviation from the reference condition is a measure of the
effect of stressors on the ecosystem. A site is considered to be in 'good' condition if it is in the
condition we would expect to see if it were minimally exposed to the stressors of concern (i.e., if
it is equivalent to reference condition). Thus, 'good' condition is defined relative to our
expectations for a particular system rather that against an absolute benchmark of ecosystem
attributes (Bailey et al. 2004).
The diversity in the physical, chemical, and biological characteristics of the wadeable streams of
the Interior Columbia Basin must be considered when defining reference condition and
calculating stream ecological condition. For example, a stream with finer-sized substrate and
low riparian structure may be typical of an undisturbed stream in one ecoregion while those same
characteristics may represent a more disturbed condition in a forested/mountainous ecoregion.
The method used to rate stream condition in a way that accounts for natural geophysiological
condition is to compare sites within each ecoregion to a set of reference sites from that same
ecoregion. Because ecoregions have similar characteristics in terms of soil, climate, geology,
and vegetation, it follows that the streams of an ecoregion would have similar stressors as well as
similar responses to those stressors. Although ecoregions do not necessarily account for all
natural variation they do provide a template for refining the expected condition of streams
throughout a broad and variable area. Methods for establishing reference condition are discussed
in the next section.
Methods
Quality Assurance
The field protocols (Peck et al. 2006) and laboratory procedures used were those developed by
EPA for the Western Pilot project. Numerous crews conducted field sampling. Consistency and
adherence to the methods was insured by crews participating in training sessions, annual training
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refreshers, and field audits conducted by EPA personnel. Also, a proportion of the sites were re-
sampled to provide estimates of variability to evaluate metrics.
Site Selection
The sample frame is the population of all of the streams from which a set of sample reaches can
be selected. The sample frame for this study was all perennial wadeable streams channels
mapped at 1:100,000 scale within the Interior Columbia River Basin boundary. Sites were
selected from wadeable streams (most 1st through 3rd order) using EMAP probability sample
design described previously and landscape maps (USGS digital line graphs) overlaid with
hydrography (EPA River Reach File 3 and the USGS PNW river reach file data). The stream
sample locations were selected in proportion to their occurrence (Overton et al. 1990, Stevens
and Olsen 2004).
Sites selected from the sample frame for sampling were subjected to an evaluation process to
insure that they were actually part of the target population (both wadeable and perennial) and
could be accessed (safe to access, landowner permission). Data were collected from 215 sample
sites (Map 2). Sites are listed in Appendix 1.
Sampling Locations
( Reference Site
( Probablistic Site
( Both Probablistic and Reference Site
CA
NV
Map 2. Sample locations of probability and reference sites.
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Reference Site Dataset
Reference sites came from three sources: EMAP western pilot probability sites, EMAP western
pilot focus area probability sites, and handpicked sites sampled as part of other regional EMAP
projects (REMAP sites) in the states of Oregon and Washington. These sites were screened for
having minimally disturbed condition yielding 163 reference sites for this analysis (Map 2). The
Western Pilot and EMAP focus area sites were screened by personnel at EPA's ORD (Corvallis).
The criteria used were that the sites were in a least disturbed condition based on evaluation of
water quality and physical habitat parameters (Stoddard et al. 2005b). These sites were also
screened by state personnel from Oregon DEQ and Washington Department of Ecology using
knowledge from field observations and photo interpretation to give additional verification that
these sites were appropriate for use as reference sites (Drake 2004, Merritt 2007). Sites from
previously conducted Regional EMAP studies (R-EMAP) within the basin were subjected to the
same screening techniques. All data from reference sites were collected with the same (or nearly
the same) field protocols as the probability sites (Peck et al. 2006). Sites used from earlier
REMAP studies had slight variation in methods - for example, fewer cross sectional measures
for substrate (Hayslip et al. 1994). A minimum of 10 reference sites was needed to generate
thresholds for each indicator in each ecoregion.
Field and Laboratory Methods
Field data were collected during summer low-
flow period from stream reaches whose length
is generally 40 times the wetted channel width
(150m minimum reach length) following the
EMAP wadeable stream field protocols (Peck
et al. 2006). These methods are briefly
described here.
Water Quality
Data for 11 water quality parameters were
collected at all sites. Measurements of
temperature and conductivity were collected in
situ. Water samples were analyzed for acid
neutralizing capacity (ANC), chloride,
dissolved organic carbon (DOC), ammonium, nitrate, total phosphorous (TP), and sulfate.
Dissolved oxygen (DO) was measured with a meter except in Oregon where Winkler titration
was used.
Physical Habitat
The following three types of habitat parameters were measured or estimated:
In-chonnel parameters: Thalweg profile (a longitudinal survey of the deepest part of the
channel), and presence/absence of fine sediments were collected at either 100 or 150 equally
spaced points along the stream reach. A subjective determination of the habitat unit designations
(e.g. riffle, glide, pool) was made at each point. Crews also tallied large woody debris along the
reach.
Photo: S. Hubler, ODEQ
10
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EPA Region 10, Office of Environmental Assessment
Transect parameters: Measures/observations of channel wetted width, depth, substrate size,
canopy closure, and fish cover were taken at eleven evenly spaced transects in each reach.
Gradient measurements and compass bearings were collected between each of the 11 transects to
calculate reach gradient and channel sinuosity. Also, measures and/or visual estimates of riparian
vegetation structure, human disturbance, and bankfull height and width were taken at transects.
Reach parameters: Channel morphology class for the entire reach was determined and
instantaneous discharge was measured at one optimally chosen cross-section.
Vertebrates
The objectives of the vertebrate assemblage assessment were to 1) collect all except the rarest
species in the assemblage and 2) collect data for estimates of relative abundance of species in the
assemblage. Fish were sampled with one-pass electrofishing in all portions of the sample reach.
Fish were identified, counted, and measured. Crews also collected fish voucher specimens.
Crews captured and identified amphibians but retained no amphibian vouchers. Although these
methods were not used to estimate absolute abundance, standardized collection techniques were
important for consistent measures of proportionate abundance of species.
Benthic Invertebrates
Macroinvertebrates were collected at the same 11 transects used for collecting habitat data with a
D-frame kick net (500 |j,m mesh). Transect samples were combined into one composite sample
per site. Indicator values were based on a subsample of 300 organisms identified to the lowest
practical taxonomic level.
Landscape Data
The watershed or 'upstream
contributing area' associated with each
sample point was delineated using 30-
meter digital elevation models and
ArcInfo/ArcMap GIS software (ESRI
Inc. 2002). An example of a sample
site watershed is shown in Figure 1
Within this area, landcover metrics
such as % forest or % barren were
calculated. Digital coverages from the
National Land Cover Database
(NLCD) were used as the base data for
land cover. The Analytical Tools
Interface for Landscape Assessments
(ATtlLA 3.x), an Arc View Software
extension (Ebert et al. 2000), was used
to calculate the metrics. Landscape
data were also used to calculate
sediment delivery.
Figure 1. Example of watershed in relation to a typical
sample reach.
11
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EPA Region 10, Office of Environmental Assessment
Analysis Methods
Reference Condition Methods
Data from reference sites were grouped by ecoregion to create relatively homogenous classes to
account for the ecological variability across the basin. Thresholds for 'good' versus 'poor'
condition were calculated from a minimum of 10 reference sites in each ecoregion (Appendix 2).
When 10 sites were not available, level 3 ecoregions were aggregated with others to which they
had the greatest geophysiographic similarity. It was necessary to aggregate ecoregions 15, 16,
17, and 41 (Rockies and Idaho batholith) and ecoregions 10 and 80 (Columbia Plateau and
Northern Basin and Range). The remaining ecoregions (4, 9, 11, and 77) had separate reference
condition thresholds. There were no samples in Snake River Plain so reference site thresholds
were not calculated for that ecoregion.
Threshold values were calculated for
metrics that have been shown in previous
EMAP evaluations to have meaningful
relationships to ecological condition, have
relatively high reproducibility (Kaufmann
et al. 1999), and have adequate data
quantity (little or no missing data) across
both the reference site and probability data
sets. Reference condition thresholds were
calculated for the following 20 metrics
(Table 2).
Table 1. The number of reference sites by ecoregion and
combined ecoregions.
Aggregated Ecological
Regions
Northern Rockies
(mountainous)
Pacific Northwest
(mountainous)
Northern Xeric Basins
(xeric)
Level III Ecoregion
(ecoregion number)
Blue Mountains (11)
Northern Rockies (15)
Idaho Batholith (16)
Middle Rockies (17)
Canadian Rockies (41)
Cascades (4)
Eastern Cascades (9)
North Cascades (77)
Columbia Plateau (10)
North Basin Range (80)
Site
Count
21
21
61
14
27
18
Table 2. Ecological condition metrics calculated with data for both reference and probability sites.
Stressor Category
Water chemistry
Riparian characteristics
In-channel complexity
Fine sediment
Metrics Calculated
sulfate, chloride, phosphorous, nitrogen, pH, and conductivity
riparian disturbance (agricultural types), riparian disturbance (all types), riparian
vegetation structure (all 3 layers), canopy density at mid-channel
large woody debris volume, in-stream fish cover, relative bed stability, %pool and
glide habitat, residual pool area
% fine-sized sediment, % sand+fine-sized sediment, embeddedness, total
suspended solids, turbidity
For each ecoregion, we used all the available reference site data to develop thresholds for
"good", "fair", and "poor" condition for each condition and stressor indicator. Thresholds were
based on the distribution of values in the set of reference sites. For indicators where high values
indicated better condition (e.g. quantity of large woody debris), we used the 25th percentile of the
distribution of the reference site values to distinguish between "good" (similar to the set of
reference sites) and "fair" (somewhat different from the set of reference sites). The 5th percentile
12
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EPA, Region 10, Office of Environmental Assessment
was used to distinguish between "fair" and "poor" (very different from the set of reference sites).
For indicators where high values indicate disturbance (or poorer condition; e.g. fine sediment),
the thresholds were reversed (the 75th percentile of the distribution of the reference site values
was used to distinguish between "good" and "fair" condition , and the 95th percentile was used to
distinguish between "fair" and "poor" condition.
Scoring was conservative to account for the fact that, although minimally disturbed, reference
sites may have some level of human disturbance. By using the 25th percentile as the threshold
point for passing or failing (deciding that a site is not in Reference Condition) we are saying that
there is a 25% chance that the sites identified as being a reference condition may not indeed be in
a least-disturbed condition. Meaning that one quarter of the sites would be mistakenly identified
as deviating from reference condition. So we are being environmentally conservative by
assuming that the reference sites may have some level of human disturbance. Thresholds for the
selected variables are in Appendix 2 and the number of reference sites used for each calculation
is in Appendix 3.
Cumulative Distribution Functions
The statistical design of the EMAP dataset
allows for the extrapolation of results from
sampled sites to the greater target
population. Any of the data metrics can be
quantitatively described using cumulative
distribution functions (CDF's), which show
the stream length represented in the target
population (or proportion of length) that has
values for an indicator at or below some
specific value of interest (Figure 2) In this
hypothetical example 50% of the stream
length has <25 biological integrity score and
are considered impaired. This is an effective
way to show the extent of impairment based
on a particular metric for the entire
population. Once this distribution is
established, thresholds can be drawn at any
point in the distribution.
100
75
50
J3)
C
_o
E
2 25
10 20 30
Biological integrity score
40
Figure 2. Example of a hypothetical CDF showing a
threshold between impaired and full support and the
associated proportion of stream length in each category.
Relative Extent Calculation
The relative extent calculation is used to determine which stressor(s) have the greatest extent of
impact on the target population. Relative extent for each of selected indicators was calculated by
comparing the value from each probability site to the reference condition cut-off categories by
ecoregion to determine if they were in poor, fair, or good condition. These site 'ratings' were
compiled and weighted to determine the kilometers of streams in the Basin within each of the
three condition categories
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EPA, Region 10, Office of Environmental Assessment
Condition Indicator Calculation- Observed to Expected (O/E) Value
Benthic macroinvertebrate O/E was calculated for each of the probability and reference sites.
The observed value was calculated from the site field data. The expected value was developed
by modeling the probability of taxa presence based on gradients within a set of environmental
variables that are not altered by humans. This model was developed from reference streams
located throughout the western United States (Stoddard et al. 2005b) and expected values at each
site were calculated by the EPA EMAP team. An O/E value of 1 implies that all of the taxa
expected at a reference site are present. A value less than 1 implies a loss of taxa as compared to
that expected at reference sites. Sites were rated as 'poor' or 'good' if they had an O/E score of
<0.5 or >0.9 respectively. For example, if a site has less than 50% of the expected taxa then it is
in a condition of low biotic diversity for the macroinvertebrate assemblage and represents a
'poor' condition. Likewise, if the site has more than 90% of the expected condition then the site
has high biotic diversity relative to what would be expected and therefore has a 'good' condition.
Sites with O/E scores between these two thresholds are considered in 'fair' condition.
Ecoregions were not used as a factor in the development of the O/E scores.
Relative Risk Determination Methods
The Relative Risk Ratio expresses the association between stressors and the biological
indicators. Relative risk is a common method for communicating human health information (e.g.
risk of heart disease relative to diet or smoking). Relative risk estimates for this report are used
to measure the likelihood that the most disturbed or 'poor' condition of a biological indicator
will occur in streams that are also in a most disturbed or 'poor' condition for a particular stressor.
We used the O/E metric (macroinvertebrate taxa loss metric) described above as the response
variable in comparison to the environmental stressors to estimate the relative risk of the biota to
various stressors.
Following methods in Van Sickle et al. (2006), we calculated the relative risk for each
environmental stressor as the ratio of stream km where the stressor was 'poor' and the O/E score
was 'poor' to the stream km where the stressor was 'good' and the O/E score was 'poor'.
Relative risk (RR) is defined as the ratio of the two probabilities;
Relative Risk = Risk of poor biological condition , given poor stressor condition
Risk of poor biological condition, given good stressor condition
The Relative Risk calculation is made from the estimated stream lengths that have the various
combinations of good-poor biological and stressor condition. The stream extent estimates were
generated from the comparison of probability site data to reference site thresholds. The
following contingency table is an example that shows the approach using turbidity as the
stressor.
Stream length
estimate
O/E index
Good
Poor
total
Turbidity disturbance class
Good
A: 25891
B:3210
A+B: 29101
Poor
C: 6564
D: 5835
C+D: 12399
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EPA, Region 10, Office of Environmental Assessment
The risk of finding a most-disturbed condition of macroinvertebrate taxa loss in streams that
have most-disturbed condition for turbidity is estimated as:
=D/(C+D) 5835/12399=0.47
Likewise, the risk of finding a most-disturbed condition of macroinvertebrate taxa loss in streams
that have a least disturbed condition for turbidity is estimated as:
=B/A+B 3210/29101=0.11
Combining the two probabilities (0.47 + 0.11) yields a relative risk of 4.3. Therefore, we are 4.3
times more likely to find poor condition for macroinvertebrate taxa loss in streams where the
condition for turbidity is poor. We report this relationship only for environmental stressors
where there was adequate data to make the calculation. Following Van Sickle et al. (2006) a
minimum of five sites were needed in each cell of the O/E to stressor contingency table to
estimate relative risk. Relative risk was calculated for the list of stressors that could be rated as
poor-fair-good based on the adequacy/completeness of the reference site data and if the
convention that all four cells of the relative risk contingency table had a minimum of five sites
was met. The 13 metrics analyzed are the same as those listed in Table 2, excluding
conductivity, chloride, riparian disturbance - all types, canopy density, fish cover, residual pool
area, and slow-water habitat.
Extent of Resource
There is an estimated 109,486 km of
wadeable, perennial (target) streams in the
Interior Columbia Basin as represented in the
sample frame. Of the total sites selected,
about 32% were deleted from the final set of
sample sites based on site evaluation
findings. These sites could not be sampled
due to site-specific issues related to physical
access and safety and land owner denial of
access (Figure 3). A total of 215 probability
sites were sampled, which represents
approximately 75,000 km (74,976 km actual)
of wadeable streams. These sites are
considered representative of the target
population as they are wadeable, perennial, and are within the Interior Columbia Basin boundary.
Also, these sites had adequate macroinvertebrate data needed for the analysis. Therefore, this
report is an analysis of about 69% of the total target stream length in the Interior Columbia Basin
for most metrics.
15
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EPA, Region 10, Office of Environmental Assessment
No
Permission
13%
Inaccessible
18%
Sampled
69%
Figure 3. Fate of sites targeted for sampling
following site evaluation expressed as percent of
total stream length (stream length 109,486).
Stream Order
The wadeable streams in the sample were mostly
nd
rd
1st order sample represents a proportionately large
number of stream miles due to the far larger 1st
order stream length in the ecoregion.
Site Distribution by State
The Interior Columbia stream extent includes
large portions of Oregon and Washington,
portions of Montana, Wyoming, Utah, and
Nevada, and almost all of Idaho. Most of the
stream length that was represented by this sample
was in Idaho with 43% of the total stream length,
followed by Montana, Oregon, and Washington
(Figure 5). Site count and stream length by State
are in Appendix 4.
1", 2"", and 3M order streams (Figure 4). The ^
number of samples were relatively equally §,
distributed between the three stream orders. Each
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EPA, Region 10, Office of Environmental Assessment
MT-
Pacific
Northwest
Xeric
North
Site Distribution by Aggregate Level III Ecoregions
The Interior Columbia basin is primarily mountainous with the greatest stream extent being
represented in the Rocky Mountain ecoregions (Northern, Middle, and Canadian Rockies) and
the Idaho Batholith. The Interior Columbia basin spans portions of 10 Level III Ecoregions
(USEPA 2003a, Omernik 1987). These
ecoregions were aggregated into three
ecological regions to aid in the description of
the basin: the Northern Rockies, the Pacific
Northwest, and the Northern Xeric Basins. The
majority of the streams represented by the
sample occur in the mountainous Northern
Rockies with the remaining streams relatively
equally representing the mountainous Pacific
Northwest and the Northern Xeric Basins
(Figure 6). The land area categorized as xeric is
a substantial portion of the upper Columbia
Basin, however perennial wadeable streams are
rare in the xeric areas. Only 7.5% of the target
stream length occurs in these areas. Stream
length and site counts by ecoregion are in
Appendix 5.
MT.
Northern
Rockies
Figure 6. Proportion of target stream length
represented in the 3 aggregate ecoregions (stream
length=74976 km).
Ecological Condition Assessment
For this assessment, the general condition of the
Interior Columbia Basin streams is described using
indicators of physical habitat, water chemistry,
vertebrate species presence, and macroinvertebrate
biological integrity. The purpose of this section is
to describe the wadeable streams in the context of
their biotic and abiotic characteristics as well as
the watershed setting. Statistics presented (means,
medians) for the condition metrics are weighted by
target stream network to be representative of the
region.
Physical Setting-Stream Description
As with the overall Interior Columbia Basin, the landcover associated with the watersheds of
wadeable streams is predominately forest land, followed by rangeland and barren land-cover
categories (Figure 7). The other cover classes that are relatively rare include wetlands, open-
water, alpine areas, agriculture, mining and urban cover types.
17
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EPA, Region 10, Office of Environmental Assessment
100
80
0
D
0
D 6°
y
0
g 40
20
0
Median D25%-75%
I Non-Outl er Range
0 Outliers * Extremes
c
i
)
j
H
i
~i -i
L
Forest Rangeland Barren Other
Land cover type
Figure 7. Distribution of land cover types in the watersheds of
wadeable streams of the Interior Columbia Basin ("other" includes
wetlands, open water, alpine areas, agriculture, mining, and urban).
The wadeable streams in the Interior Columbia Basin are small with mean bankfull width of 4.3
m and depth of 19.4 cm. Channel slopes were moderate (median 4.1 %) and channel habitat type
was about equal in terms of fast (riffles, rapids, cascades, and falls) and slow (pools and glides)
water. Dominant canopy cover type was typically coniferous, averaging 41% of the reach length
(median 27 %). Stream bed substrate was generally coarse. The gravel sized substrate (2-64 mm
diameter) was the most common substrate size followed by cobble (64-250 mm) (Figure 8).
% Stream Bed
8 g g g g
i
*
t
3
*
i <
r
3 I
D
*
i r
r
LS
Median D 25%-7
Extremes
:
r c
5
»
I
!
^
:
i
5% I N
i
I I
on-Outlie
. r
r Range o Outliers
r.
D I ;
Fines Gravel Boulder Organic
Sand Cobble bedrock/hardpan Misc
Substrate size classes
Figure 8. Presence of substrate particle size classes (stream length= 74,976).
18
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EPA, Region 10, Office of Environmental Assessment
Vertebrate Assemblage
Sufficient sampling effort for vertebrates was conducted at 124 of the 215 sites (57%),
representing a total target stream length of 45,006 km that could be assessed for condition based
on vertebrates. The most common reason for not sampling was permit restrictions due to
presence of Threatened and Endangered species (mostly salmon or bull trout). We note that
permit restrictions are probably not random, and therefore the assessment results cannot be
inferred to that part of the target network where there were permit restrictions. Other obstacles
to vertebrate sampling were insufficient time available, extreme terrain/water conditions, or
equipment failure. These other problems are probably more random in nature, and even though
not sampled, results from the assessed population (in terms of proportion of length) probably
apply to this part of the network as well.
Vertebrates were present at most sites, representing 81% of the 45,006 km of stream length
(Table 3). Fish were more broadly distributed than amphibians which were only present in 43%
of the stream length. Alien fish were somewhat common, present at over 25% of the stream
length while alien amphibians were rare (1 site had a bull frog). Vertebrate species richness in
wadeable streams ranged from 0 to 7 species and presence of only one fish species was most
typical (Figure 9). Fish were not captured from 29% of the stream miles that were sampled.
Table 3. Vertebrate presence in the Basin (n=124 sites, stream length=45,006 km).
Information
Vertebrates present
Amphibians present
Fish present
Salmonids present
Alien fish present
% stream
length
81
43
71
70
26
Comment
Neither fish/amphibians captured at 19% of the stream length
The tailed frog was the most common amphibian species
Rainbow trout were the most common salmonid
Brook trout were the most common alien fish species present
Q) ^
CO
E
=3
VERT_
N
M
RICH
VERT
_AL_
FISH
RICH
Nt
Median Q 25%-75% I Non-Outlier Range o Outliers
1 [ 1 1
T
i,T_RICH Amph_nat_rich
Fish_alien_rich Amp_alien_rich
Figure 9. Distribution of native and alien vertebrate richness metrics
within the target stream length ( stream length= 45,006 km).
19
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EPA, Region 10, Office of Environmental Assessment
Six fish families and five amphibian families (Appendix 6) were present. Salmon/trout species
were the most broadly distributed followed by sculpins (Figure 10). Bell toads (tailed frogs)
were the most commonly observed amphibian.
IUU
- ». Qt\
Zg oil
*i en
o) ou
c
EAf\
4U
(0
+*
tr\ on
\n £\j
n
i |
Fish Amphibians
i i
n n n n ^ ^
_v<^
ON
Vertebrate family
Figure 10. Extent of vertebrate families present in wadeable streams of the Basin
(n=102, stream length=30,395km).
Rainbow and cutthroat trout were by far the most common species in the Interior Columbia
Basin wadeable streams followed by brook trout, an introduced char species native to the eastern
United States (Figure 11). The other alien species that were present, smallmouth bass and brown
trout, were rare. The presence of alien species is a concern as these species can alter the balance
of the aquatic community. Alien species can compete for space/food resulting in displacement
or decline in abundance of native species. Presence of alien species can also disrupt
predator/prey relationships with various results such as loss of species diversity. Interbreeding
between native and alien species can reduce abundance and fitness of native species. An example
is the case of sympatric bull trout and brook trout resulting in hybridization. Twelve species of
amphibians were sampled with tailed frog being by far the most common (Figure 12). Sampled
fish and amphibian species and their descriptions are in Appendix 6.
20
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EPA, Region 10, Office of Environmental Assessment
ou
^p
^* /in
_ 4U
0)
c in
o 30
on
re ^v>
£
+j
//\ rfi /\
OT 10
n
n, -
II III II II II i i i
Species
Figure 11. Extent of most common fish species in the Basin (n=124, stream length=45,006 km).
30
o) 20
% 15
E 10
re
0) p
is 5
Species
Figure 12. Species presence of amphibians in the Basin (n=124, stream length=45,006 km).
21
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EPA, Region 10, Office of Environmental Assessment
Benthic Macroinvertebrate Assemblage
Aquatic benthic macroinvertebrate assemblages are useful for
describing overall biological integrity of wadeable streams. These
assemblages are responsive to changes in water quality and physical
conditions. Much research has been focused on these relationships,
thus there is a well developed body of knowledge from which to
interpret results. Macroinvertebrates have relatively long life-cycles
(typically a year or more) and because they are not very mobile,
macroinvertebrate assemblage structure can be used to interpret recent
condition. Benthic macroinvertebrate data were available from all
sample sites and from all reference sites.
Photo: S. Hubler, ODEQ
A useful metric for indicating the sensitivity to human disturbance is the proportion of taxa in the
orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddis flies) known
as EPT taxa (Plafkin et al. 1989). These orders are known to be relatively sensitive to
disturbance or reduced water quality and physical habitat quality. In the Interior Columbia
Basin, 50% of the target stream length has at least 24 EPT taxa (Figure 13) which comprised at
least 45% of the total taxa enumerated (Figure 14).
100
0 5 10 15 20 25 30 35 40 45
Number of EPT taxa
Figure 13. CDF of number of EPT taxa
(stream length=74,976 km).
) 10 20 30 40 50 60 70
EPT taxa (% Total)
Figure 14. CDF of percent of taxa that are
EPT (stream length=74,796 km).
The taxa richness metric O/E is another benthic macroinvertebrate indicator of biotic integrity.
Results across the Interior Columbia Basin wadeable streams show that about 50% of the
wadeable stream length is in the 'good' category based on the O/E ratio exceeding the 0.9 taxa
presence threshold (Figure 15). "Poor" condition occurs in about 13% of the wadeable stream
length where the O/E ratio is below the 0.5 poor threshold (36% poor and 36% fair).
22
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EPA, Region 10, Office of Environmental Assessment
(0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Observed/Expected invertebrate taxa
Figure 15. CDF of observed to expected macroinvertebrate taxa
presence with thresholds for poor-fair-good condition (stream
leneth=74.976 km).
The poor-fair-good results for benthic
invertebrate taxa presence vary across
the major combined ecoregions
(Figure 16). The mountainous-
Northern Rockies ecoregions which
contain 82% of the target stream
length in the Interior Columbia Basin
have about 50% of the length rated as
"good' based on the O/E indicator.
The Mountainous Pacific Northwest
ecoregions (which contain 12% of the
target stream length) have over 80% of
the length rated in "good" condition
based on the O/E indicator. The target
stream population in the Xeric North
ecoregions have the greatest
proportion of length (20%) rated in
"poor' condition based on the O/E
indicator but the smallest proportion of
target stream length (7%).
MT-NROCK MT-PNW XE-NORTH
Ecoregion aggregates
Figure 16. Proportion of stream length in poor-fair-good
condition basedon O/E score for three aggregated ecoregions.
Stream lengths (km) in each ecoregion are shown.
Stressor Condition Assessment
Stressors indicator descriptions
The chemical and physical condition of streams affects the presence, abundance and distribution
of aquatic species. The following is a description of the occurrence of the primary stressor
23
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EPA Region 10, Office of Environmental Assessment
metrics (Table 2) in the Interior Columbia Basin. These metrics are the basis for the description
of the condition of the Basin in the following sections on extent and risk to biota. Summary
statistics for these metrics are in Appendix 7 for water quality metrics and Appendix 8 for
physical habitat and sediment metrics.
Water chemistry indicators
Sulfur is a nutrient that occurs naturally in aquatic systems from rock weathering and volcanism.
Arid and semi-arid areas with sulfur containing rocks may have relatively high sulfate (SO4"2)
concentrations as the soils are not as thoroughly leached resulting in high amounts of dissolved
solids in surface and ground water. Sources of sulfate from human disturbance are from air
pollution including combustion of coal, petroleum, and smelting of sulfide ores resulting in
atmospheric deposition. Surface inputs of
sulfate are from mining activity and
agricultural fertilizers. There is no EPA water
quality criterion or suggested value for sulfate
in surface waters as levels of sulfate do not
generally occur in streams that are considered
harmful to biota. However, sulfate is a useful
metric as it can be indicative of human
disturbance. The mean value for the Basins
streams was 10.6 mg/L with 50 % of the
wadeable stream length having estimated
sulfate concentrations of <1.8mg/L (Figure
100
10 15 20 25
Sulfate (mg/L)
17).
Figure 17. CDF of sulfate (stream length=74,976 km).
100
~ 75
£
D)
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EPA Region 10, Office of Environmental Assessment
from human disturbance can reduce the productivity of streams that are typically low in
nutrients. For example, marine derived nutrients delivered to Pacific Northwest coastal rivers
and streams have declined due to large reductions in returns of anadromous fish (Gresh et al.
2000).
Total phosphorous includes dissolved, particulate and dissolved ortho-phosphate forms. The
dissolved orthophosphate form is readily assimilated by algae. In natural streams, phosphorous
is usually <1 mg/L (Hem 1992). Natural
streams draining from volcanic soils in the
Northwest can have hundreds of mg/L of total
phosphorous however. Sources of excess
phosphorous from human causes are domestic
and industrial sewage, animal feeding
operations, fertilization of agricultural areas,
and surface erosion. USEPA (1986)
recommends <0.05 mg/L total phosphorous
for streams delivering to lakes. The mean
total P" value for the streams of the Basin was
0.03 mg/L with 50% of the wadeable stream
length having estimated phosphorous
concentrations of <0.01 mg/L (Figure 19).
100
75
i
CO
50
25
0.00
0.05
0.10
0.15
0.20
Total phosphorus (mg/L)
Figure 19. CDF of phosphorous (stream lngth=74976
km).
Nitrogen is frequently the most important nutrient in streams as the inorganic form can often
stimulate primary productivity (bacteria and algae). Inorganic nitrogen (nitrate-nitrite and
ammonium) is the predominant form of nitrogen in streams. Excess nitrogen can contribute to
eutrophication. Human sources of nitrogen
include fertilizing, animal feeding operations, 100
sewage/wastewater discharge, and _
atmospheric deposition. There is not an EPA
criterion for nitrogen but a nitrate
concentration of <0.3 mg/L is considered
preventative of eutrophi cation (McDonald et
al. 1991). The mean total nitrogen value for
the streams of the Basin was 0.19 mg/L with
50% of the wadeable stream length having o.o 0.1
estimated nitrogen concentrations of <0.11
mg/L (Figure 20). Approximately 10% of the
stream miles had total nitrogen >0.3 mg/L.
Si 75
£
D)
g
50
I
V)
25
0
0.2 0.3 0.4
Total nitrogen (mg/L)
0.5 0.6
Figure 20. CDF of total nitrogen (stream length
= 74976 km).
pH is the concentration of hydrogen ions in moles per liter water expressed as a log scale (log
1/[H+]. pH can have direct and indirect effects on stream water chemistry and on biota. Direct
effects include fish reproductive and benthic invertebrate emergence success. Acidification in
other parts of the country has been implicated with declines in fish populations (Haines and
Baker 1986), changes in fish communities (Cusimano et al. 1989) and elevated fish tissue
25
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EPA Region 10, Office of Environmental Assessment
mercury content (Gloss et al.1990). Indirect
effects include interactions with the
equilibrium of other chemicals in the water.
For example the solubility of many metals
changes with changed pH. EPA's pH range to
protect aquatic life is 6.5 to 9.0. The range in
the Basin's streams was 6.2 to 9.2 with
median value of 7.7 (Figure 21).
100
6.0 6.5 7.0 7.5 8.0 8.5 9.0
Figure 21. CDF of pH (stream length 74976
km).
Conductivity measures the ion concentration
of water. Soluble ions such as nitrates,
phosphorous, sulfate, and chloride, can be
increased due to human activities as explained
previously. Therefore, conductivity can be a
useful indicator of water quality impairments
from mining and agriculture when it differs
from expected natural levels. EPA does not
have a suggested conductivity criterion as it
varies greatly across streams. Conductivity in
the Basin's streams averaged 144.8 |j,S/cm and
the median was 92 |j,S/cm (Figure 22).
100
S? 75
0 100 200 300 400 500 600
Conductivity (uS/cm)
Figure 22. CDF of conductivity (stream length =
74,976 km).
Dissolved oxygen and water temperature are critical for the maintenance of aquatic organisms
that use aerobic respiration. Many human activities result in decreasing dissolved oxygen and
increasing water temperatures including removal of riparian vegetation, water withdrawals,
industrial and municipal point source discharges and agricultural discharges, increased sediment
delivery and inputs of organic material. Dissolved oxygen (DO) content is related to turbulence,
temperature, and atmospheric pressure. Decreased DO levels are associated with inputs of
organic matter, loss of substrate interstitial spaces due to sedimentation, as well as increased
temperature and reduced stream flow (MacDonald et al. 1991). In productive streams, dissolved
oxygen fluctuates substantially with biological activity (e.g. level of photosynthesis/respiration)
so single grab sample measurements may be of limited use. Also, dissolved oxygen was not
measured at some sites (see Appendix 7). The EPA's (1986) coldwater criterion for dissolved
oxygen is a 7-day mean of 9.5 mg/L (6.5 mg/L interstitial) and a 1-day minimum of 8.0 mg/L
(5.0 mg/L interstitial). The mean dissolved oxygen estimated for 44,805 km of stream length
(n=167) was 9.1 mg/L and the median was 9.3 mg/L. Conclusions must be drawn with caution,
as DO is temporally variable and a single measurement is of questionable value for
characterizing stream condition.
26
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EPA Region 10, Office of Environmental Assessment
Stream temperature is variable depending on air temperature and time of sampling. Many
physical parameters affect water temperature in streams including depth, flow, quantity of shade
from riparian vegetation and slope-aspect, and groundwater-hyporheic interactions. Human
activities can increase water temperatures by increasing the heat load. These include, removal of
riparian vegetation, water withdrawals, and alteration of sediment transport that can result in
stream widening. Water temperature criteria recommended by EPA in the Pacific Northwest
(USEPA 2003b) focus on protecting use by salmonids at their various life history phases. The
most stringent recommendation is 9°C to protect bull trout spawning. A criterion of 16°C
applies to waters with salmon /trout juvenile rearing areas, while 18°C applies to salmon and
trout migration routes. Mean water temperature estimated for 61,130 km of wadeable stream
length (n=195) was 10.7°C with a median of 10.0°C.
Riparian Condition Indicators
Intact riparian areas are important for maintaining stream function for many reasons including 1)
influencing channel form through root strength; 2) contributing roughness elements (LWD) that
force pools and form steps; 3) providing allochthonous inputs of organic matter, and; 4) shading
and insulating the channel which influences both summer and winter water temperature, and 5)
preventing delivery of sediment and nutrients due to surface erosion. The influence of the
riparian zone on streams is variable. For example, the amount of shading provided by the
riparian vegetation is related to stream width. Human activities associated with reduced riparian
integrity include stream adjacent activities such as logging, animal grazing, agriculture, roads,
and urbanization. Metrics used in the assessment related to riparian condition were riparian
vegetation structure, human disturbance index and mid-channel canopy density (shade). There
are no criteria associated with these metrics, rather they are compared to the reference condition
to determine how they relate to the overall condition of the Interior Columbia Basin.
Riparian structure of three vegetation heights
(canopy >5m, understory 0.5 to 5m, and ground
cover >0.5m) was calculated as the proportion
of the reach with the possible range of values
from 0 to 1. The proportion of the reach with
riparian vegetation presence (combination of all
three vegetative layers) averaged 0.78 for the
Basin's streams with a median of 0.95 (Figure
23).
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Riparian Vegetation Presence (prop, reach)
Figure 23. CDF of riparian vegetation presence
(stream length=74,976 km).
Human disturbance in the riparian zone is calculated as a proximity-weight disturbance index,
which combines the extent of disturbance (based on presence or absence) as well as the
proximity of the disturbance to the stream (Kaufmann et al. 1999). Most streams had some level
27
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EPA Region 10, Office of Environmental Assessment
100
of human-caused riparian disturbance when including all disturbance categories (EMAP metric
W1_HALL) recorded in the field (see Peck et al. 2006). Possible values for this metric range
from 0 (no disturbance recorded in any of the 22 plots observed at each sample reach) to 1.5
times the number of disturbance types. So a
value of 1 is equivalent to having one
disturbance type present in every plot, and a
value of 1.67 is equivalent to having one type in
every plot plus one type adjacent to every plot.
Thus, even low values indicate disturbance
presence. The average disturbance index was
0.79 and median value of 0.51 (Figure 24).
Human disturbance was not observed in an
estimated 29% of the estimated stream length.
Some level of disturbance from agriculture
(pasture and crops) occurred in about 36% of
the estimated stream length assessed.
£
O)
I
E
ro
£
OT
75
50
25
0.0
0.5 1.0 1.5 2.0 2.5
Human Disturbance (prop. wt. pres.)
3.0
Figure 24. CDF of human disturbance in the
riparian zone (stream length 74,976 km).
Changes to the riparian canopy can increase
the amount of direct radiation that reaches the
stream. Less canopy density can result in
greater temperature fluctuations both
seasonally and daily. Mean mid-channel
canopy density was 63% with median 73% for
the assessed stream length (Figure 25).
100
0 10 20 30 40 50 60 70 80 90 100
Mid-channel Canopy density (%)
Figure 25. CDF of canopy density measured at
mid-channel (stream length=74,390 km).
In-channel habitat complexity indicators
The inputs of water, sediment, and LWD combined with slope, surficial geology, and channel
size give streams their characteristic channel complexity. A stream's ability to process inputs of
water, sediment and LWD, in the face of natural disturbance regimes, maintains this channel
complexity. Human-caused disturbances, which are commonly lower in magnitude but more
frequent than natural disturbance events, can alter water, sediment, and LWD inputs. These
disturbances can alter the dynamic equilibrium of streams and result in a loss of channel
complexity and function. Human alterations to the landscape that can affect inputs include
logging, agriculture, urbanization, road construction, water withdrawal, and grazing. The four
metrics used to assess channel complexity are relative bed stability (RBS), large woody debris
volume, fish cover from large elements (rock, wood, human structures), and area and abundance
of pools.
28
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EPA Region 10, Office of Environmental Assessment
The metric used to evaluate a stream's stability in relation to its sediment load is relative bed
stability (RBS). RBS is a comparison of bed substrate size divided by the sediment size that is
mobilized during bankfull flow events (Kaufmann et al. 1999). This value is an index of
substrate mobility. If this mobility is greater or less than expected, this indicates human-caused
sedimentation stress may be present (USEPA 2006a). A large negative value for RBS indicates
there are more fine sediments than expected for a stream based on its ability to transport
sediment (excess fines). RBS is expressed as a LoglO value so a value of -2 means the median
particle size is 100 times smaller that expected. Low RBS values (-4 to -2) would be found in
channels that have very mobile substrate and are frequently moved by small flood events
(USEPA 2006a). A large positive RBS value (2 to 4) indicates the substrate is coarser than
expected. For example, a stream that has been scoured to bedrock by a debris flow or an
armored canal would have a high RBS value.
In watersheds where sediment supply is high
relative to the streams capacity to transport its
bed load, there will typically be excess fine
sediment present (Dietrich et al. 1989). This
is the typical situation when land use activities
increase hill slope erosion and this situation is
exacerbated when riparian vegetation is also
damaged or removed (Lisle 1982). In the
Interior Columbia Basin, mean RBS value was
-1.11 and a median of -1.02 (Figure 26).
These values are not excessively low
indicating that the streams are relatively stable
in relation to their sediment load.
100
-4 -3 -2-10 1
Channel Stability (Log 10 RBS)
Figure 26. CDF of loglO of the relative bed
stability (stream length=64,280 km).
Large woody debris (LWD) recruited to the
channel from the riparian zone and hill slopes
is important to stream function in channels
that are influenced by LWD (typical of
streams in the Pacific Northwest). LWD, as
single pieces or in accumulations, alters flow
and traps sediment, thus influencing channel
form and related habitat features
(Montgomery and Buffmgton 1993). Loss of
LWD inputs can result in long-term alteration
of channel form as well as loss of habitat
complexity in the form of pools, overhead
cover, flow velocity variations, and retention
and sorting of spawning-sized gravels.
100
80
120
160
200
LWD volume (M3/100m)
Figure27. CDF of large woody debris
volume (stream length=74,976 km).
29
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EPA Region 10, Office of Environmental Assessment
The volume of LWD including pieces greater than 10 cm diameter ranged from zero to over 213
m3 per 100 m of stream reach. The mean volume was 26.0 m3 and the median was 7.2 m3
(Figure 27). The mean number of pieces of LWD greater than 10 cm diameter in and
overhanging the bankfull width of the channel was 22 pieces per 100 m of stream reach with a
median of 14 pieces.
Many structural components of streams are used by fish as concealment from predators and as
hydraulic refugia. The metric offish cover (including LWD, boulders, undercut bank and human
structures) is indicative of the overall
complexity of the channel which is beneficial
to other organisms as well. This metric is
estimated as the sum of the areal cover from
these four fish concealment types and can
range from 0 to 3.5 The mean was 0.26 areal
cover proportion. This is approximately
equivalent to one cover type recorded as a ' 1'
(sparse) and one cover type recorded as a '2'
(moderate) at each of the 11 transects in a
100
75
E
ro
50
oc
25
0.0
sample reach. The median value was 0.18 for
the estimated stream length assessed (Figure
28).
0.2 0.4 0.6 0.8
Rsh Cover (areal proportion)
1.0
Figure 28. CDF of fish cover (stream length=
74,976 km).
100
Habitat units are the reach scale classification of habitat based on physical stream features. Fast
water areas (i.e. riffles and cascades) are those with higher water velocity, surface turbulence and
often shallower water depth in wadeable streams (Bisson et al. 1982). Slow water areas (i.e.
glides and pools) have low water velocity, less surface turbulence and are the deeper portion of
the streams. The formation of these fast and slow water areas is a function of processes that
influence stream bed form including stream size and flow, slope, substrate type, and availability
and quantities of large roughness elements
that force pools or accumulate sediment that
form steps (Montgomery et al. 1995). Having
a variety of flow velocities and depths is a
characteristic of channel complexity as biotic
assemblages use these habitat types differently
resulting in increased species richness. Human
disturbance that results in the loss of
roughness in streams results in habitat
simplification which can be indicated by the
dominance of riffle habitat (Kershner et al.
2004). Also, habitat complexity can be
indicated by pool abundance.
0 10 20 30 40 50 60 70 80 90 100
Figure 29. CDF of pool and glide habitat types.
(stream length=74,159 km).
30
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EPA Region 10, Office of Environmental Assessment
Percent slow water is a subjective evaluation of the length of stream that is composed of pools
and glides. The mean stream length that was slow water (glides and pools) was 40% and median
31% (Figure 29). The second metric, mean residual pool area (m2 perlOO m stream reach), is
calculated from stream depth measurements along the thalweg. Residual pool depth can be
visualized as the depth of the water that would remain in a reach if the upstream flow was
stopped. Residual pool quantity is an indicator of habitat space. Mean residual pool area ranged
from 0-54 m2/100m with mean of 6 m2/100m (median 4 m2/100m).
Sediment quantity indicators
Suspended and deposited sediment occurs at background levels and is important to the ecological
function of streams. Sediments transport nutrients, toxicants and organic matter in concentrations
that affect stream function. Natural levels of sediment inputs create important habitat features
and maintain the dynamic equilibrium of streams. Excessive or decreased sediment inputs can
result in impaired function. Also, altered sediment input can have direct and indirect effects to
aquatic biota. Human activities that increase fine sediment inputs include erosion from forestry,
mining, roads, agriculture, stream channel alterations, and dredging. Decreases in sediment
inputs are from sediment being trapped behind dams or the aftermath of extreme stream scour
events such as landslides associated with logging. Negative effects from decreases in sediment
delivery and transport are a much less frequent and widespread issue compared to excess
sediment.
Negative effects to fish habitat from the deposition of fine sediment are well known (reviews by
Waters 1995, Chapman 1988). Fine sediment deposition can result in the following impacts to
salmonid habitat: 1) reduction of ability of fish to build suitable redds, 2) asphyxiation of
developing embryos (hinders water flow decreasing oxygen saturation and removal of metabolic
waste), 3) reduction of successful emergence of fry from redds due to burial (blockage of
interstices prevents emergence of larvae), 4) reduction of availability of habitat for juveniles and
small adult fish (such as family Cottidae) by the filling of cobble interstices used for hiding and
cover and filling of pools.
Deposition of excess fine substrate to streams can affect the macro-invertebrate assemblage in
several ways including: reducing availability of larger sized particles for attachment, interstitial
space for movement between particles, and intra-substrate current velocity and associated
dissolved oxygen concentration. Bjornn et al. (1977) reported higher densities of
macroinvertebrates in riffles with lower proportions of fine sediment versus those with high
proportions. Richards and Bacon (1994) found a significant negative correlation between the
abundance of macroinvertebrate taxa and individuals with the presence of fine sediment
(<1.5mm diameter) in the hyphoreic zone (subsurface). Macroinvertebrate taxa have varying
degrees of tolerance to fine sediment inputs. Some families such as Baetidae, Simuliidae, and
the order Plecoptera are shown to have greater degree of population decline with exposure to
elevated levels of fine sediment (Gulp et al.1986) while most taxa in the family Chironomidae
appears to be less affected by exposure to fine sediment.
The metrics used to assess deposited fine sediment are quantity of fine-sized surface substrate
and embeddedness. Quantity of fine-sized sediment is the estimate of the substrate particle size
that is <2mm diameter (for sand and smaller size fraction) and <0.06mm (for the 'fines'
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EPA Region 10, Office of Environmental Assessment
fraction). The mean percent sand plus fines was 24% and the median value was 20% (Figure
30). About 11% of the target streams are dominated by substrate <2 mm (sand and fines >50%
of the substrate). Embeddedness is the amount that larger substrate particles are surrounded by
or 'embedded into' smaller particle sizes expressed as a percent. All streams had some level of
embeddedness with mean and median value of 52% (Figure 31).
100
20 40 60 80
Sand & Fine Substrate (%)
100
20 40 60
Embeddedness (%)
Figure 30. CDF of percent sand and fine ubstrate
<2mm diameter (stream length=74,976 km).
Figure 31. CDF of streambed substrate
embeddedness (stream length=74,976 km).
Sediment in suspension also affects stream biota. Fish can be displaced from preferred habitats,
reducing their ability to obtain food and avoid predators. Aquatic insects exposed to turbidity
can experience increased drift rates and reduced abundance (Gulp et al. 1986). Suspended
sediment and turbid conditions can have direct effects on primary production due to decreased
light penetration, which can inhibit photosynthesis. Decreases in primary production especially
to periphyton (aquatic flora growing on submerged substrates) can adversely effect productivity
of higher trophic levels which are dependent on primary production as a food source. A
reduction in standing crop of primary producers has effects on other strata of the trophic
hierarchy (e.g. zooplankton, benthic macroinvertebrates, and fish). A secondary affect of
suspended sediment is degradation or loss of habitat due to deposition of this suspended material
at diminished flow. Fine sediment deposition is discussed previously. Two metrics were used to
assessing suspended sediment: total suspended solids (TSS) and turbidity.
Total suspended solids (TSS) are composed of suspended sediment- typically sand, silt, and clay
as well as organic particles and organisms. The size of particles entrained varies with flow
characteristics (e.g. velocity, gradient, and turbulence). Also, deposition of suspended sediment
is related to particle size and diminished flow. The very fine particle fraction, or wash load
(<0.0635mm) tends to stay in suspension for the length of the fluvial system. Turbidity is the
optical property of water that describes the amount of light that is refracted or absorbed.
Primarily related to the amount silt and clay, turbidity is also influenced by organic particles and
compounds and organisms. There is no standardized relationship between turbidity and TSS as
the size, weight, and refraction characteristics of the particles contributing to turbidity vary by
watershed and in time (USGS 2003).
32
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EPA Region 10, Office of Environmental Assessment
Suspended sediment and turbidity are highly
related to flow conditions with highest
amounts occurring during high flow and storm
events. Because the EMAP samples are
collected during summer low flows water
quality criteria are not relevant to these
measures. However these data are useful for
calculations based on comparisons to
reference condition (see next section on
Relative Extent and Relative Risk). The mean
total suspended solids were 3.2 mg/L with
median value of 1.2 mg/L (Figure 32). Mean
turbidity was 0.93 NTUs (0.28 median).
100
0 5 10 15 20 25
Total suspended solids (mg/L)
Figure 32. CDF of total suspended solids (stream
length=73,758 km).
Relative Extent of Stressors
Important water quality and physical habitat
stressors were identified based on the
comparison of reference site to probability
site data. Abiotic stressors (water quality,
riparian, channel complexity, and sediment
metrics), were identified and expressed in
terms of their relative extent of the stream
length assessed in the poor, fair or good
category. Values associated with the
following stressor extent graphs are in
Appendix 9
Photo: G. Merritt, WA Ecology
Results of water chemistry stressor metrics varied from 15% to 37% of the stream extent in the
poor condition category. Over 30% of the stream length assessed was in the 'poor' condition
category for sulfate, phosphorous, and conductivity (Figure 33). Both pH and nitrogen had
<20% of the stream length in the poor condition category.
33
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EPA Region 10, Office of Environmental Assessment
Sulfate
Chloride
Phosphorous
Nitrogen
PH
Conductivity
0%
20% 40% 60%
Stream length (%)
80%
100%
Figure 33. Extent of stream length in poor (red), fair (orange), and good (blue) condition for selected water quality
indicators based on comparison of probability site data to thresholds developed from reference site data.
Riparian condition stressor results were variable (Figure 34). Most stream length assessed was
in good condition for the quantity of riparian vegetation (69%) and mid-channel canopy density
(75%) with <15% of the stream length in the poor condition category for these stressors.
Riparian disturbance from all human causes observed was substantial in many streams resulting
in 38% of the stream length being in a poor condition category compared to the reference
condition. The results for riparian disturbance from agricultural sources only (pasture and crops)
were somewhat less (29%).
Riparian Dist. Ag.
Riparian Disturbance
Riparian Veg.
Shade
0% 20% 40% 60% 80% 100%
Stream length (%)
Figure 34. Extent of stream length in poor-fair-good condition for selected physical habitat indicators based on
comparison of probability site data to thresholds developed from reference site data.
34
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EPA Region 10, Office of Environmental Assessment
Channel complexity stressor results were fairly consistent (Figure 35). Most metrics indicated a
poor condition for 18% about of the stream length assessed. The metric that varied substantially
was slow water habitat (% pools and glides). The large majority of stream length was in the
good category (86%) for this stress indicator.
Woody debris
Fish cover
Channel stability
Pool depth
% pools/glides
0% 20% 40% 60% 80%
Stream length (%)
100%
Figure 35. Extent of stream length in poor - fair- good condition for selected physical habitat indicators based on
comparison of probability site data to thresholds developed from reference site data.
Generally, the sediment stressor metrics all yielded similar results, with the estimated stream
length in poor condition ranging from 18 to 27% (Figure 36). Embeddedness had the greatest
extent in poor condition and TSS had the least. Turbidity and TSS would be expected to have
similar results and they were almost identical with 60-70 % of stream length classified as good
condition. Embeddedness, the most subjective measure, gave results very similar to sand/fines.
Inclusion of the sand fraction of the substrate (2mm to 0.06mm particle diameter) rather than
fines alone (0.06 and smaller particle diameter) resulted in a slightly greater amount of stream
length in the poor category (26% versus 22% for fine-sized alone).
35
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EPA Region 10, Office of Environmental Assessment
0% 20% 40% 60%
Stream length (%)
80%
100%
Figure 36. Extent of stream length in poor -fair- good condition for sediment indicators based on comparison of
probability site data to thresholds developed from reference site data.
Relative Risk
The relative risk analysis estimates relevance of the effects or associations of the stressors to the
stream biota. Benthic macro-invertebrate taxa loss was the biotic indicator for this comparison
where site condition is compared to the O/E macro-invertebrate score. Recall from the
calculation of relative risk (see methods page 14), that relative risk is the likelihood that the
biotic assemblage based on benthic macroinvertebrate taxa loss will be poor when the stress
indicator is poor. Values associated with the following relative risk graphs are Appendix 10. Of
the 21 stress indicators used in the extent analysis, 13 were useable for the relative risk
estimation due to methods restrictions (Appendix 10) Relative risk estimates greater than one
are considered to pose a significant effect on the biotic indicator (Van Sickle et al. 2006).
All stress indicators used in the relative risk analysis exceeded the significance threshold of one
(Figure 37 and Appendix 10). Each stressor category had at least one stressor that exceeded the
relative risk level of four. All indicators of excess sediment, both bed sediments and suspended,
had high relative risk scores (exceeding four).
36
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EPA Region 10, Office of Environmental Assessment
Sulfate
Phosphorus
PH
Nitrogen
Riparian disturb. Ag.
Riparian vegetation
LWD
Channel stability
Embeddedness
Sand/Fines
Turbidity
Fines
TSS
0.0
2.0
4.0 6.0
Relative Risk
8.0
10.0
Figure 37. Risk to benthic assemblage (taxa loss) relative to the environmental stressor condition.
Viewing the relative risk in relation to the extent of indicators across the stream length assessed,
we see that some indicators with high relative risk were not found to be widely occurring
problems (Figure 38). For example, riparian vegetation (all three levels combined) was poor in
only an estimated 13% of the stream length, but where this problem does occur the biota are at
high risk of being in a poor condition. However, some stressors are both broadly occurring and
have high relative risk (Figure 38). For example, the extent of poor condition for most of the
sediment indicators is relatively high (> 18%) and the relative risk associated with these
indicators is also high, ranging from 4.3 for turbidity to 8.1 for sand/fines.
37
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EPA Region 10, Office of Environmental Assessment
40
3- 30
c
o
+3
'B
c
o
O
i_
O
o
0.
20
10
S04
ripdist
em^ed 0/oSAFN
%FN
TIM*
RBS
ripveg
4 6
Relative Risk
8
10
Figure 38. Summary of extent of stressors in poor condition in relation to relative risk. Red circle emphasizes
stressor indicators with both high percent of stream length in poor condition and with high relative risk. Refer to
Appendix 3 for definition of abbreviated indicator names in this figure.
Conclusions and Recommendations
In general, most streams of the basin are in fair or good condition based on the results of the
metrics that could be analyzed. Primary stressors in terms of both extent and risk to biota are
excess fine sediment, riparian disturbance from grazing/crops, sulfate, and phosphorous levels.
The results of this analysis support that conditions for aquatic biota would be improved by
reducing activities that contribute fine sediment to streams. Erosion and mass wasting controls,
protecting and restoring riparian zones, and insuring recruitment of large woody debris at a
watershed scale would reduce the stressors influencing aquatic biota.
For this evaluation, we only used one biotic assemblage in which to determine risk to biota. It is
preferable to use more assemblages (fish or periphyton) so that the conclusions are more robust.
Using multiple assemblages is preferred as a stressor that may be very relevant to one
assemblage may have less of a signal for another.
The abundance of reference sites in this Basin allowed condition thresholds for most level III
ecoregions to be developed (some Level III ecoregions had to be combined due to insufficient
sites). The more refined reference condition thresholds improved the estimates of stream
condition.
38
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EPA Region 10, Office of Environmental Assessment
Additional work that will be pursued using this dataset for the Interior Columbia Basin is to
evaluate landscape metrics and models in order to further evaluate the relation of sediment
delivery to streams and the associated risk to biota.
Using ecoregions as a way to account for variability and thus 'scale' the stressor cut-offs for
thresholds of poor-fair-good was reasonable. However, additional work to account for factors
(e.g. base lithology, watershed area, and slope) that influence sensitivity to human disturbance
(Kauffman and Hughes 2006) would be useful.
Streams in xeric areas are rare so their occurrence in the sample selection frame was also very
low. Coupled with access issues and land-owner denials, very large areas had no sample sites.
For future EMAP flowing waters projects, it may be necessary to modify the design to ensure
that a greater number of streams are sampled in the xeric areas.
39
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EPA Region 10, Office of Environmental Assessment
Citations
Bailey, R. C., R. H. Norris, et al. (2004). Bioassessment of freshwater ecosystems: Using the
reference condition approach. New York, Kluwer Academic Publishers.
Bisson, P. A, J., L. Nielson, R. A. Palmason, and L.E. Gore. (1982). A system of naming
habitat types in small streams, with examples of habitat utilization by salmonids during low
stream flow. Pages 62-73 in N. B. Armantrout, ed. Acquisition and utilization of aquatic habitat
information. American Fisheries Society. Portland, Oregon.
Bjornn, T. C., M. A. Brusven, et al. (1977). Transport of granitic sediment in streams and its
effects on insects and fish. Technical Report Projects B-036-IDA. Forest, Wildlife and Range
Station, University of Idaho. Moscow.
Barbour, M. T., J. B. Stribling, et al. (1995). The multimetric approach for establishing
biocriteria and measuring biological condition. Biological assessment and criteria: tools for water
resource planning and decision-making. W.S. Davis and T. P. Simon editors. Lewis Publishers.
London.
Bryce, S. 1997. Primary distinguishing characteristics of Level III Ecoregions of the continental
United States. U.S. Environmental Protection Agency. Washington D.C.
Website:ftp://ftp.epa.gov/wed/ecoregions/us/useco_desc.doc
Chapman, D. W. (1988). "Critical review of variables used to defined effects of fines in redds of
large salmonids." Transactions of the American Fisheries Society 117: 1-21.
Gulp, J. M., F. J. Wrona, et al. (1986). "Response of stream benthos and drift of fine sediment
deposition versus transport." Canadian Journal of Zoology 64: 1345-1351.
Cusimano, R.F., J.P. Baker, W.J. Warren-Hicks, V. Lesser, W.W. Taylor, M.C. Fabrizio, D.B.
Hayes, B.P. Baldigo. (1989). Fish Communities in Lakes in Subregion 2B (Upper Peninsula of
Michigan) in Relation to Lake Acidity. EPA/600/3-89/021. U.S. Environmental Protection
Agency. Washington D.C.
Gloss, S.P., T.M. Grieb, C.T. Driscoll, C.L. Schofield, J.P. Baker, D. Landers, and D.B. Porcella.
(1990 ). Mercury Levels in Fish from the Upper Peninsula of Michigan (ELS Subregion 2B) in
Relation to Lake Acidity. EPA/600/3-90/068. U.S. Environmental Protection Agency.
Washington D.C.
Dietrich, W. E., J. W. Kirchner, et al. (1989). "Sediment supply and the development of the
coarse surface layer in gravel bed rivers." Nature 340(20): 215-217.
Drake, D. (2004). Selecting reference condition sites: an approach for biological criteria and
watershed assessment. Technical Report WASO4-002. Oregon Department of Environmental
Quality. Portland, Oregon.
40
-------
EPA Region 10, Office of Environmental Assessment
Ebert, D., T. Wade, J. Harrison, and D. Yankee. (2000). Analytical tools interface for landscape
assessments (ATtlLA) User Guide. Version 1.004. Office of Research and Development, U.S.
Environmental Protection Agency. Las Vegas, NV.
ESRI. 2002. Arclnfo Version 8.3., Environmental Systems Research Institute, Inc. Redlands
California.
Gresh, T., J. Lichatowich, and P. Schoonmaker. (2000). "An estimation of historic and current
levels of salmon production in the northeast Pacific ecosystem: evidence of a nutrient deficit in
the freshwater systems of the Pacific Northwest." Fisheries 25(1): 15-21.
Haines, T.A. and J.P. Baker. (1986). "Evidence offish population responses to acidification in
the Eastern United States.' Water. Air. & Soil Pollution 31(3-4):605-629.
Hawkins, C., R.H. Norris, IN. Hogue, and J.W. Feminella. (2000). "Development and
evaluation of predictive models for measuring the biological integrity of streams. Ecological
Applications." 10(5): 1456-1477
Hayslip, G. and L. Herger. (2000). Ecological condition of upper Chehalis Basin streams. EPA-
910-R-01-005. U.S. Environmental Protection Agency, Region 10, Seattle, Washington.
Hayslip, G., L. Herger and P. Leinenbach. (2004). Ecological condition of western Cascades
ecoregion streams. EPA-910-R-04-005. U.S. Environmental Protection Agency, Region 10,
Seattle, Washington.
Hayslip, G., DJ. Klemm, and J.M. Lazorchak. (1994). 1994 field operations and methods
manual for streams in the Coast Range ecoregion of Oregon and Waashington and the Yakima
River basin of Washington. Environmental Monitoring Systems Laboratory. U.S.
Environmental Protection Agency. Cincinnati, Ohio.
Hem, J.D. (1989). Study and interpretation of the chemical characteristics of natural water. 3rd
Edition. Water Supply Paper 2254. U.S. Geological Survey. Washington D.C.
Herger, L. and G. Hayslip. (2000). Ecological condition of streams in the Coast Range
ecoregion of Oregon and Washington. EPA-910-R-00-002. U.S. Environmental Protection
Agency, Region 10, Seattle, Washington.
Herger, L., Weiss, A., Augustine, S., and G. Hayslip. (2003). Modeling fish distribution in the
Pacific Northwest Coast Range ecoregion Using EMAP Data. EPA/910/R-03/000. U.S.
Environmental Protection Agency, Region 10, Seattle, Washington.
Herlihy, A. T., J. L. Stoddard, et al. (1998). "The relationship between stream chemistry and
watershed land cover data in the mid-Atlantic region, U.S." Water, Air, and Soil Pollution 105:
377-386.
41
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EPA Region 10, Office of Environmental Assessment
Hughes, R.M. (editor). (1993). Stream indicator and design workshop. EPA/600/R-93/138.
U.S. Environmental Protection Agency. Corvallis, Oregon. 84pp.
Hughes, R. M. (1995). Defining acceptable biological status by comparing with reference
conditions. Biological Assessment and Criteria: Tools for water resource planning and decision
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probability survey of ecological integrity in the U.S.A." Hydrobiologia 422/423: 429-443.
Kaufmann, M. and R. M. Hughes (2006). "Geomorphic and anthropogenic influences on fish and
amphibians in the Pacific Northwest coastal streams." American Fisheries Society Symposium
48: 429-455.
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gravel channels, northwest California." Water Resources Research 18(6): 1643-1651.
MacDonald, L.H., A.W. Smart, and R.C. Wissmar. (1991). Monitoring guidelines to evaluate
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06-03-0_ Environmental Assessment Program. Washington Department of Ecology. Olympia,
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response, and assessment of channel condition. Washington State Timber/Fish/Wildlife
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D.C.
42
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EPA Region 10, Office of Environmental Assessment
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43
-------
EPA Region 10, Office of Environmental Assessment
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"Classification of species attributes for Pacific Northwest freshwater fishes." Northwest Science
73(2): 81-93.
44
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EPA Region 10, Office of Environmental Assessment
Appendices
Appendix 1. List of probability sites.
SITE_ID
WIDP99-0501
WIDP99-0502
WIDP99-0503
WIDP99-0504
WIDP99-0508
WIDP99-0510
WIDP99-0511
WIDP99-0514
WIDP99-0515
WIDP99-0516
WIDP99-0520
WIDP99-0524
WIDP99-0595
WIDP99-0596
WIDP99-0597
WIDP99-0599
WIDP99-0600
WIDP99-0602
WIDP99-0603
WIDP99-0605
WIDP99-0607
WIDP99-0610
WIDP99-0611
WIDP99-0613
WIDP99-0614
WIDP99-0615
WIDP99-0690
WIDP99-0695
WIDP99-0697
WIDP99-0698
WIDP99-0699
WIDP99-0701
WIDP99-0724
WIDP99-0725
WIDP99-0726
WIDP99-0727
WIDP99-0729
WIDP99-0737
WIDP99-0738
WIDP99-0768
WIDP99-0770
WMTP99-0509
STATE
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
MT
WGT_COND
716.2288873
716.2288873
716.2288873
572.9831097
1432.457775
716.2288873
572.9831097
716.2288873
716.2288873
716.2288873
716.2288873
572.9831097
716.2288873
358.1144437
477.4859249
1432.457775
572.9831097
572.9831097
358.1144437
1432.457775
572.9831097
859.4746648
572.9831097
1432.457775
716.2288873
572.9831097
716.2288873
572.9831097
716.2288873
859.4746648
716.2288873
1432.457775
572.9831097
1432.457775
1432.457775
358.1144437
716.2288873
1432.457775
572.9831097
358.1144437
716.2288873
1004.895995
STRAHLER
2
2
2
3
1
2
3
2
2
2
2
3
2
3
2
1
3
o
J
3
1
o
J
5
o
6
i
2
o
5
2
o
6
2
4
2
1
o
6
i
i
o
5
2
1
3
3
2
2
LAT_DD
46.56095
44.03402
46.75859
47.79687
43.68952
48.32913
43.55661
45.51286
44.66203
45.71372
44.71089
43.48905
44.91362
45.86143
43.23258
46.62902
44.81675
45.85814
42.72991
45.02333
46.60219
44.05506
45.07931
45.43438
48.75671
43.66638
46.86041
44.4664
44.13731
46.36471
47.10877
43.52574
44.38768
46.66214
46.93882
42.85248
47.19756
44.70859
45.89351
42.00739
44.26809
46.09771
LON_DD
-114.78078
-115.81346
-116.35642
-116.50889
-115.085
-116.1561
-114.80021
-113.99451
-116.95473
-115.64173
-113.78403
-115.12612
-116.22571
-116.61914
-116.77989
-115.16426
-114.14713
-114.91584
-111.4436
-114.44525
-115.52497
-113.23232
-116.0938
-116.24657
-116.73369
-114.53681
-116.03806
-111.91133
-115.18667
-116.74636
-116.73196
-111.25428
-114.69394
-115.7863
-116.46172
-112.07726
-115.63723
-115.83017
-115.44778
-115.21883
-115.87505
-114.09283
Ecoregionlll
16
16
15
15
16
15
16
16
11
16
17
16
16
11
80
15
16
16
17
16
15
17
16
11
15
16
15
17
16
10
15
17
16
15
15
80
15
16
16
80
16
17
45
-------
EPA Region 10, Office of Environmental Assessment
Appendix 1 continued. List of probability sites.
SITE ID
WMTP99-0515
WMTP99-0516
WMTP99-0600
WMTP99-0607
WMTP99-0608
WMTP99-0609
WMTP99-0704
WMTP99-0705
WMTP99-0748
WMTP99-0801
WNVP99-0514
WNVP99-0615
WNVP99-0622
WNVP99-0663
WNVP99-0668
WNVP99-0674
WNVP99-0680
WNVP99-0686
WORP99-0512
WORP99-0518
WORP99-0523
WORP99-0528
WORP99-0529
WORP99-0530
WORP99-0541
WORP99-0542
WORP99-0547
WORP99-0548
WORP99-0551
WORP99-0554
WORP99-0559
WORP99-0560
WORP99-0605
WORP99-0606
WORP99-0607
WORP99-0608
WORP99-0613
WORP99-0622
WORP99-0625
WORP99-0626
WORP99-0630
WORP99-0662
WORP99-0667
WORP99-0677
WORP99-0685
STATE
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
NV
NV
NV
NV
NV
NV
NV
NV
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
WGT COND
1004.895995
803.916796
803.916796
803.916796
1004.895995
1004.895995
2009.79199
1004.895995
803.916796
2009.79199
180.6338246
180.6338246
250.1083726
180.6338246
250.1083726
135.4753684
180.6338246
250.1083726
36.38058849
391.8411011
783.6822021
36.38058849
72.76117698
72.76117698
36.38058849
72.76117698
29.1044708
36.38058849
72.76117698
36.38058849
36.38058849
29.1044708
72.76117698
18.19029425
36.38058849
36.38058849
24.25372567
36.38058849
29.1044708
36.38058849
48.50745133
293.8808258
1175.523303
48.50745133
29.1044708
STRAHLER
2
o
J
3
o
J
2
2
1
2
o
J
1
2
2
1
2
1
3
2
1
2
2
4
2
1
1
2
1
o
3
2
1
2
2
o
3
1
3
2
2
2
2
3
2
4
o
3
1
0
o
J
LAT DD
48.82479
46.97382
48.83676
48.3536
47.20769
46.29743
47.987
46.68552
46.37611
46.51149
41.71531
41.99294
41.476
41.41776
41.87257
41.80692
41.67083
41.43368
44.95604
45.88877
44.44759
44.47633
44.84428
44.33353
45.09325
44.5391
44.82201
44.20764
45.18545
44.83757
44.53202
44.58357
45.09683
45.09772
44.43241
44.57589
44.84534
44.04778
45.17222
44.85492
44.75647
45.36827
45.11462
44.1384
45.09665
LON_DD
-114.52056
-112.62295
-114.36791
-113.87986
-115.21949
-113.2271
-114.56456
-114.55801
-112.70751
-113.08087
-115.22807
-114.94997
-116.14632
-116.03335
-115.08706
-115.70369
-115.43303
-116.54478
-118.37558
-117.08959
-117.36697
-120.13192
-118.49367
-118.64122
-118.66608
-119.03187
-120.15535
-119.28908
-121.64106
-118.87883
-118.47835
-118.41064
-121.5505
-120.10121
-118.51285
-118.49073
-121.00327
-119.25261
-118.73584
-118.72644
-119.41316
-119.44512
-116.85546
-121.59992
-119.60892
Ecoregionlll
41
17
41
41
15
17
15
15
17
17
80
80
80
80
80
80
80
80
11
11
11
11
11
11
11
11
11
11
4
11
11
11
9
10
11
11
10
11
11
11
11
10
11
9
11
46
-------
EPA Region 10, Office of Environmental Assessment
Appendix 1 continued. List of probability sites.
SITE ID
WORP99-0691
WORP99-0692
WORP99-0698
WORP99-0701
WORP99-0704
WORP99-0710
WORP99-0721
WORP99-0724
WORP99-0728
WORP99-0734
WORP99-0740
WORP99-0745
WORP99-0762
WORP99-0768
WORP99-0769
WORP99-0775
WORP99-0780
WORP99-0787
WORP99-0792
WORP99-0794
WORP99-0800
WORP99-0803
WORP99-0806
WORP99-0815
WORP99-0823
WORP99-0830
WORP99-0841
WORP99-0842
WORP99-0851
WORP99-0852
WORP99-0854
WORP99-0856
WORP99-0860
WORP99-0864
WORP99-0866
WORP99-0871
WORP99-0877
WORP99-0883
WORP99-0890
WORP99-0891
WORP99-0917
WORP99-0923
WORP99-0924
WORP99-0928
WORP99-0929
STATE
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
WGT COND
36.38058849
72.76117698
36.38058849
36.38058849
36.38058849
72.76117698
36.38058849
48.50745133
36.38058849
72.76117698
587.7616515
587.7616515
36.38058849
48.50745133
36.38058849
36.38058849
48.50745133
29.1044708
36.38058849
48.50745133
29.1044708
36.38058849
72.76117698
36.38058849
470.2093213
587.7616515
48.50745133
36.38058849
72.76117698
43.65670619
29.1044708
48.50745133
72.76117698
36.38058849
36.38058849
36.38058849
72.76117698
36.38058849
1175.523303
36.38058849
29.1044708
36.38058849
36.38058849
72.76117698
29.1044708
STRAHLER
2
1
2
2
2
1
2
4
2
1
2
2
2
4
2
2
4
3
2
4
3
2
1
2
o
5
2
5
2
1
4
3
4
1
2
2
2
1
2
1
2
3
2
2
1
o
J
LAT DD
45.02468
44.65353
44.30712
45.24921
44.71049
44.37471
44.89811
44.09685
44.39835
44.67177
45.2455
44.89855
44.9714
44.62217
45.05124
44.99865
44.61828
44.90831
44.95446
44.62214
44.20009
45.2055
44.84933
44.26846
44.42964
45.2719
45.03431
44.711
45.19196
45.16741
44.77941
44.0151
44.77885
45.05222
44.27744
44.95509
44.96174
44.56008
45.15893
44.55866
44.44277
44.76812
44.99637
45.30179
44.99278
LON_DD
-119.1499
-118.72859
-119.17495
-121.65964
-118.80126
-119.25914
-118.38238
-119.51709
-118.67973
-118.54373
-119.20877
-117.42313
-119.29882
-120.20966
-118.66491
-119.80257
-119.29951
-118.31331
-120.11004
-118.57732
-119.3513
-121.4153
-118.78612
-119.97696
-117.51413
-117.46555
-118.97695
-118.95006
-121.54788
-119.95186
-118.45238
-119.33692
-118.68596
-119.45154
-119.59314
-118.54965
-118.60722
-120.17442
-117.31785
-121.63343
-119.81356
-119.90937
-118.72535
-121.44914
-120.19689
Ecoregionlll
11
11
11
4
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
9
11
11
11
11
11
11
9
10
11
11
11
11
11
11
11
11
11
9
11
11
11
9
11
47
-------
EPA Region 10, Office of Environmental Assessment
Appendix 1 continued. List of probability sites.
SITE ID
WORP99-0931
WORP99-0935
WORP99-0937
WORP99-0947
WORP99-0948
WORP99-0972
WORP99-0977
WORP99-0985
WORP99-0997
WORP99-1002
WORP99-1003
WORP99-1021
WUTP99-0738
WWAP99-0501
WWAP99-0502
WWAP99-0504
WWAP99-0507
WWAP99-0512
WWAP99-0513
WWAP99-0516
WWAP99-0522
WWAP99-0524
WWAP99-0526
WWAP99-0527
WWAP99-0529
WWAP99-0531
WWAP99-0532
WWAP99-0534
WWAP99-0535
WWAP99-0538
WWAP99-0541
WWAP99-0542
WWAP99-0546
WWAP99-0563
WWAP99-0568
WWAP99-0593
WWAP99-0598
WWAP99-0611
WWAP99-0612
WWAP99-0614
WWAP99-0618
WWAP99-0622
WWAP99-0630
WWAP99-0632
STATE
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
UT
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WGT COND
72.76117698
29.1044708
29.1044708
36.38058849
36.38058849
48.50745133
36.38058849
36.38058849
72.76117698
48.50745133
29.1044708
29.1044708
142.3230481
482.0440027
482.0440027
1205.110007
602.5550033
602.5550033
28.0789671
1205.110007
482.0440027
28.0789671
18.7193114
11.23158684
28.0789671
28.0789671
11.23158684
14.03948354
14.03948354
28.0789671
28.0789671
14.03948354
11.23158684
723.066004
602.5550033
1205.110007
602.5550033
28.0789671
14.03948354
11.23158684
14.03948354
14.03948354
14.03948354
14.03948354
STRAHLER
1
3
3
2
2
4
2
2
1
4
3
o
5
2
3
3
1
2
2
1
1
3
1
4
o
3
i
i
o
5
2
2
1
1
2
3
4
2
1
2
1
2
3
2
2
2
2
LAT DD
44.78677
45.05039
44.34544
44.62332
45.09129
45.08543
44.8447
44.35053
44.25692
44.8069
44.63523
44.26681
41.79791
46.15187
46.94703
48.66948
46.26366
46.72988
47.42888
48.75608
48.1391
47.91787
47.55338
47.82841
47.98425
47.41879
47.77337
47.64945
48.02028
47.49884
47.53807
47.89761
47.63122
48.50849
48.39025
46.09432
48.20525
47.90893
47.39113
47.77379
47.90991
47.98587
47.45253
47.70092
LON DD
-118.37703
-119.34993
-119.65115
-119.63725
-119.21856
-119.0453
-119.591
-119.54309
-118.72987
-118.42878
-118.84265
-119.2195
-113.70932
-120.9786
-120.86765
-118.49916
-121.35376
-120.93914
-120.58642
-119.89609
-118.52751
-120.71826
-120.76985
-120.98266
-120.99859
-120.67906
-120.92748
-121.06659
-120.97756
-120.83942
-121.0253
-120.6963
-120.96894
-120.28161
-118.74508
-117.63915
-118.32031
-120.6473
-120.68333
-120.63449
-121.08903
-120.76811
-120.76926
-120.90719
Ecoregionlll
11
11
11
11
11
11
11
11
11
11
11
11
80
9
9
15
9
9
77
77
15
77
77
77
77
77
77
77
77
77
77
77
77
10
15
11
15
77
77
77
77
77
77
77
48
-------
EPA Region 10, Office of Environmental Assessment
Appendix 1 continued. List of probability sites.
SITE ID
WWAP99-0633
WWAP99-0635
WWAP99-0640
WWAP99-0641
WWAP99-0642
WWAP99-0681
WWAP99-0682
WWAP99-0688
WWAP99-0695
WWAP99-0697
WWAP99-0700
WWAP99-0701
WWAP99-0702
WWAP99-0704
WWAP99-0705
WWAP99-0706
WWAP99-0721
WWAP99-0722
WWAP99-0730
WWAP99-0732
WWAP99-0733
WWAP99-0735
WWAP99-0736
WWAP99-0765
WWAP99-0766
WWAP99-0768
WWAP99-0770
WWAP99-0772
WWAP99-0776
WWAP99-0777
WWAP99-0778
WWAP99-0780
WWYP99-0511
WWYP99-0585
WWYP99-0591
WWYP99-0592
WWYP99-0616
WWYP99-0662
WWYP99-0710
STATE
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WY
WY
WY
WY
WY
WY
WY
WGT COND
11.23158684
11.23158684
482.0440027
602.5550033
1205.110007
401.7033355
28.0789671
602.5550033
11.23158684
14.03948354
11.23158684
28.0789671
28.0789671
14.03948354
28.0789671
11.23158684
1205.110007
301.2775017
11.23158684
14.03948354
14.03948354
11.23158684
11.23158684
14.03948354
28.0789671
11.23158684
18.7193114
14.03948354
28.0789671
14.03948354
11.23158684
18.7193114
1174.305275
1174.305275
469.7221102
469.7221102
782.8701835
1174.305275
469.7221102
STRAHLER
3
o
6
3
2
1
2
1
2
o
J
2
3
1
1
2
1
3
1
3
o
J
2
2
o
J
3
2
1
3
4
2
1
2
3
0
1
1
3
3
4
1
3
LAT DD
47.58554
47.82426
46.25956
46.52663
46.84485
46.12959
47.54551
47.93462
47.43262
47.69859
47.45026
47.86274
47.76982
48.09626
48.03268
47.3599
48.76751
47.73425
47.46304
47.77466
47.61033
48.02649
47.94051
47.37791
47.77088
47.61561
47.41814
47.87687
47.42246
47.77921
47.64546
48.03671
42.81627
43.85899
42.65724
43.0945
43.23574
43.69302
43.51989
LON_DD
-120.92391
-120.98872
-117.48154
-121.16615
-121.18622
-118.40646
-121.04039
-120.30551
-120.53316
-120.77602
-120.65278
-121.10128
-120.84474
-120.82736
-120.86401
-120.45611
-117.75771
-117.66951
-120.65988
-120.83299
-120.89884
-120.828
-120.93223
-120.64542
-121.07639
-121.02121
-120.50828
-121.04169
-120.72813
-120.94193
-120.57664
-120.93525
-110.62881
-110.90908
-110.67103
-110.74507
-110.44743
-110.21352
-109.98189
Ecoregionlll
77
77
11
9
9
10
77
77
77
77
77
77
77
77
77
77
15
10
77
77
77
77
77
77
77
77
77
77
77
77
77
77
17
17
17
17
17
17
17
49
-------
Appendix 2. Reference condition cutoff points for thresholds to evaluate extent of good-fair-poor condition, based on comparison to probability site data. Note
similar ecoregions were combined for where the number of reference sites was insufficient to use for estimates. Ecoregion 10 and 80 and ecoregions 15,16,17,
and 41 were combined.
Metric
Ecoregions
4
Quartile
4
Extreme
9
Quartile
9
Extreme
11
Quartile
11
Extreme
77
Quartile
77
Extreme
10+80
Quartile
10&80
Extreme
15-41
Quartile
15-41
Extreme
Water Quality
S04
PTL
PHSTVL_75
PHSTVL_25
NTL
COND
CL
2.50
0.03
7.70
7.32
0.26
58.00
1.10
17.20
0.07
8.10
6.90
0.32
102.00
3.30
1.17
0.04
7.70
7.53
0.26
101.00
1.00
3.50
0.10
8.00
6.91
0.52
195.00
3.00
3.10
0.03
7.80
7.42
0.24
75.00
0.52
5.44
0.07
8.41
6.90
0.28
212.00
1.49
3.35
0.00
7.75
7.29
0.07
58.50
0.50
5.54
0.01
7.93
6.70
0.09
85.00
0.67
2.70
0.04
7.85
7.28
0.29
106.00
1.53
4.13
0.07
8.88
6.49
0.40
136.00
3.80
1.80
0.01
8.07
7.37
0.10
106.00
0.30
2.70
0.02
8.24
6.40
0.21
137.00
0.50
Riparian Condition
W1_HAG
W1_HALL
XPCMG
XCDENMID
0.00
0.13
0.95
71.12
0.00
0.85
0.68
47.59
0.00
0.71
0.91
62.70
0.67
1.08
0.77
36.63
0.00
0.03
0.80
22.33
0.48
1.82
0.05
3.21
0.00
0.33
0.75
38.77
0.00
0.67
0.05
21.66
0.68
1.15
0.14
47.33
1.50
1.50
0.00
1.47
0.00
0.33
0.86
55.68
0.12
0.74
0.36
28.28
Inchannel Habitat Complexity
V1TM100
XFC_BIG
LRBS_BW5
RP100
PCT_SLOW
PCT_FAST
18.04
0.35
-0.92
4.50
19.33
80.00
4.74
0.20
-1.73
1.09
7.88
92.12
8.43
0.25
-1.20
4.09
19.33
79.33
0.00
0.12
-1.85
2.99
4.00
96.00
3.02
0.22
-1.32
4.86
16.00
84.00
0.00
0.04
-1.52
0.77
1.33
98.67
7.67
0.17
-0.65
2.57
13.00
87.00
2.98
0.12
-1.19
1.41
11.00
89.00
0.49
0.16
-1.24
4.61
8.00
92.00
0.00
0.00
-2.93
0.58
1.67
98.33
5.02
0.25
-0.95
3.88
9.90
90.10
0.00
0.09
-1.74
2.76
0.00
100.00
Sediment Quality
TSS
PCT_FN
TURB
PCT_SAFN
XEMBED
1.15
5.00
1.00
12.73
38.83
66.00
16.67
2.00
45.45
65.00
2.60
13.33
1.21
27.50
62.73
9.00
18.95
2.00
43.81
81.18
2.00
11.43
1.00
21.90
46.92
4.56
21.90
2.00
31.43
69.64
1.36
1.90
0.12
9.52
32.73
2.46
8.57
0.15
29.09
50.00
6.50
16.67
3.13
29.52
63.75
22.90
62.86
12.80
71.43
86.67
1.50
4.76
0.23
16.19
50.62
6.00
11.43
0.45
28.57
60.83
50
-------
Appendix 3. Number of reference sites used to calculate condition thresholds by ecoregion.
Metric
Description
4
9
11
77
10&80
15,16,17&41
Water Quality
S04
PTL
PHSTVL
NTL
COND
CL
sulfate
total phosphorous
pH
nitrogen
conductivity
chloride
60
51
57
61
61
51
14
14
14
14
14
13
19
15
18
19
19
14
27
27
27
27
27
27
19
19
19
19
19
19
21
21
21
21
21
21
Riparian Condition
W1_HAG
W1_HALL
XPCMG
XCDENMID
riparian disturbance from agriculture
riparian disturbance all types
riparian vegetation structure
Mid-channel canopy density
61
61
55
61
14
14
12
14
17
17
17
17
27
27
25
27
18
18
18
18
21
21
21
20
Inchannel Habitat Complexity
V1TM100
XFC_BIG
LRBS_BW5
rplOO
PCT_SLOW
PCT_FAST
largewoody debris volume
fish cover
channel stability
residual pool area
%pools+glides
% riffle+rapids+cascades+falls
55
55
55
55
61
61
12
12
11
11
14
14
17
17
14
14
17
17
25
25
26
26
27
27
16
18
13
18
18
18
21
21
21
18
21
21
Sediment Quality
TSS
PCT_FN
TURB
PCT_SAFN
XEMBED
total suspended solids
% fines <0.06mm diameter)
turbidity
% sand+fines <2mm diameter)
embeddedness
60
61
55
61
55
14
14
12
14
12
19
21
19
21
17
27
27
25
27
25
19
18
16
18
16
21
21
21
21
21
51
-------
Appendix 4. Proportion of stream length assessed by state
(n=215, total stream length=74,976km).
State
ID
MT
NV
OR
UT
WA
WY
Stream
length (km)
32,135
12,260
1,608
9,332
142
13,784
5,715
% total
stream length
42.9
16.4
2.1
12.4
0.2
18.4
7.6
Site
count
41
11
8
84
1
63
7
Appendix 5. Estimated wadeable stream length and sample site counts by ecoregion (total stream length=74,976 km).
Aggregated Ecological
Regions
Northern Rockies
(mountains)
Pacific Northwest
(mountains)
Northern Xeric Basins
(xeric)
Level III Name
Blue Mountains (11)
Northern Rockies (15)
Idaho Batholith (16)
Middle Rockies(17)
Canadian Rockies (41)
Cascades (4)
Eastern Cascades (9)
North Cascades (77)
Columbia Plateau (10)
North Basin Range (80)
Stream length
(km)
12,697
17,858
13,895
15,282
2,613
109
4,316
2,597
2,666
2,944
Site
Count
77
19
18
17
o
5
2
12
47
8
12
Reference
site count
21
21
61
14
27
18
52
-------
Appendix 6. Species characteristics classification for aquatic vertebrate species. Fish classification based on Zaroban et al. (1999) and amphibian
classification based on EPA tolerance descriptions (Unpublished data available in S. W.I.M. database).
Family/Species
Common name
Tolerance
Habitat
Thermal
Trophic
Fish Species
Family: Catostomidae
Catostomus columbianus
Catostomus macrocheilus
Catostomus platyrhynchus
bridgelip sucker
largescale sucker
mountain sucker
tolerant
tolerant
intolerant
benthic
benthic
benthic
cool
cool
cool
herbivore
omnivore
herbivore
Family: Centrarchidae
Micropterus dolomieu
smallmouth bass
intolerant
water column
cool
piscivore
Family: Cottidae
Cottus bairdii
Cottus beldingii
Cottus cognatus
Cottus confusus
Cottus leiopomus
Cottus rhotheus
mottled sculpin
Paiute sculpin
slimy sculpin
shorthead sculpin
Wood River sculpin
torrent sculpin
intolerant
intolerant
intolerant
sensitive
sensitive
intolerant
benthic
benthic
benthic
benthic
benthic
benthic
cool
cold
cold
cold
cold
cold
invertivore
invertivore
invertivore
invertivore
invertivore
invert/piscivore
Family: Cyprinidae
Rhinichthys cataractae
Rhinichthys osculus
Richardsonius balteatus
longnose dace
speckled dace
redside shiner
intolerant
intolerant
intolerant
benthic
benthic
water column
cool
cool
cool
invertivore
invertivore
invertivore
Family: Petromyzontidae
Lampetra richardsoni
lamprey
intolerant
hider
cool
filter feeder
Family: Salmonidae
Oncorhynchus clarki
Oncorhynchus mykiss
Oncorhynchus tshawytscha
Prosopium williamsoni
Salmo trutta
Salvelinus confluentus
Salvelinus fontinalis
cutthroat trout
rainbow trout/steelhead
Chinook salmon
mountain whitefish
brown trout
bull trout
brook trout
sensitive
sensitive
sensitive
intolerant
intolerant
sensitive
intolerant
water column
hider
water column
benthic
hider
hider
hider
cold
cold
cold
cold
cold
cold
cold
invert/piscivore
invert/piscivore
invertivore
invertivore
invert/piscivore
invert/piscivore
invert/piscivore
53
-------
Appendix 6 continued. Species characteristics classification for aquatic vertebrate species. Fish classification based on Zaroban et al. (1999)
and amphibian classification based on EPA tolerance descriptions (Unpublished data available in S.W.I.M. database).
Family/Species
Common name
Tolerance
Habitat
Thermal
Trophic
Amphibian Species
Family: Bufonidae
Bufo boreas
Bufo woodhousii
western toad
Woodhouse's toad
intolerant
intolerant
edge/hider
edge/hider
cool
cool
invertivore
invertivore
Family: Dicamptodontidae
Dicamptodon aterrimus
Dicamptodon tenebrosus
Idaho giant salamander
Pacific giant salamander
very sensitive
very sensitive
benthic/hider
benthic/hider
cold
cold
invert/piscivore
invert/piscivore
Family: Hylidae
Pseudacris regilla
Pacific tree frog
intolerant
edge/hider
cool
invertivore
Family: Leiopelmatidae
Ascaphus truei
tailed frog
very sensitive
edge/hider
cold
invertivore
Family: Ranidae
Rana boy Hi
Rana cascadae
Rana luteiventris
Rana pipiens
Rana pretiosa
foothill yellow-legged
frog
Cascade frog
Columbia spotted frog
leopard frog
spotted frog
very sensitive
very sensitive
sensitive
tolerant
very sensitive
edge/hider
edge/hider
edge/hider
edge/hider
edge/hider
cold
cold
cold
warm
warm
invertivore
invertivore
invertivore
invertivore
invertivore
54
-------
Appendix 7. Summary statistics for water chemistry metrics for 215 probability sites sampled in the Interior Columbia Basin. Note the grand total of target
stream length in the basin is 109,486 km. Data for most metrics were available at all of the sample sites representing 74,976 stream km, approximately 69% of
the target stream length.
Indicator
Sulfate (SO42~)
Chloride (CT)
total
phosphorous
total nitrogen
pH
Conductivity
Dissolved
oxygen (DO)
Temperature
Turbidity
TSS
Units
mg/L
mg/L
mg/L
mg/L
-log[H]
uS/cm
mg/L
Celsius
NTU
mg/L
n
215
215
215
215
215
215
167
195
215
214
Weighted
stream
km
74976
74976
74976
74976
74976
74976
44805
61130
74976
73758
Mean
10.59
1.02
0.03
0.19
7.74
144.77
9.09
10.75
0.93
3.15
-95%
confid.
10.41
1.01
0.03
0.19
7.73
143.76
9.08
10.72
0.91
3.10
+95%
confid.
10.78
1.04
0.03
0.19
7.74
145.78
9.11
10.79
0.94
3.19
Median
1.78
0.37
0.01
0.11
7.72
92.00
9.30
10.00
0.28
1.20
Minimum
0.16
0.11
0.00
0.02
6.15
12.00
2.60
1.90
0.08
0.00
Maximum
307.05
39.95
0.42
5.54
9.21
663.00
19.70
45.50
26.50
177.36
Range
306.89
39.84
0.42
5.53
3.06
651.00
17.10
43.60
26.42
177.36
Variance
680.80
5.66
0.00
0.19
0.21
19808.18
3.29
21.48
4.07
37.78
Std.Dev.
26.09
2.38
0.05
0.44
0.46
140.74
1.81
4.63
2.02
6.15
Std.
Error
0.095
0.009
0.000
0.002
0.002
0.514
0.009
0.019
0.007
0.023
55
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Appendix 8. Summary statistics for physical habitat and sediment metrics for 215 probability sites sampled in the Interior Columbia Basin. All statistics are
weighted bases on the targeted stream networked represented by the sample sites. Note the grand total of target stream length in the basin is 109,486 km. Data
for most metrics were available at all of the sample sites representing 74,976 stream km, approximately 69% of the target stream length.
code
XSLOPE
XWIDTH
W1_HAG
W1_HALL
XPCMG
XCDENMID
PCAN_C
V1TM100
C1W_100
XFC_BIG
RP100
LRBS_BW5
PCT_SLOW
PCT_FAST
PCT_SAFN
PCT_FN
XEMBED
Indicator
slope
mean wetted width
Agricultural
disturbance
all human
disturbance
presence 3 layers
canopy structure
mid-channel
canopy density
coniferous
dominated canopy
volume LWD
in/above active
channel (class 1 >)
LWD active
channel (class 1 >)
Structural fish
cover
mean residual pool
area
log 10 [relative bed
stability]
%pools+glides
%Fast water
%Sand+fines<2m
m
%fines (<0.06mm)
embeddedness
Units
%
m
prox. Wtd.
Sum
prox. Wtd.
Sum
proportion
reach
%
proportion
reach
nrVlOOm
Pieces/
100m
Areal
prop.
m2/100m
reach
N/A
% reach
% reach
% reach
% reach
%
n
215
215
215
215
215
214
215
215
215
215
203
202
214
214
215
215
215
stream
km
74976
74976
74976
74976
74976
74390
74976
74976
74976
74976
64996
64280
74159
74159
74976
74976
74976
Mean
5.22
4.06
0.37
0.79
0.78
63.23
0.41
26.00
21.56
0.26
5.93
-1.11
40.39
58.29
24.01
11.43
52.10
-95%
confid.
5.19
4.03
0.37
0.78
0.77
63.02
0.40
25.68
21.36
0.26
5.89
-1.11
40.19
58.08
23.86
11.30
51.96
+95%
confid.
5.25
4.08
0.38
0.79
0.78
63.44
0.41
26.31
21.75
0.26
5.97
-1.10
40.60
58.50
24.15
11.56
52.24
Median
4.14
2.79
0.00
0.51
0.95
72.79
0.27
7.17
14.09
0.18
4.18
-1.02
31.00
69.00
20.00
4.76
52.07
Min.
0.15
0.19
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.01
-4.29
0.00
0.00
0.00
0.00
5.40
Max.
34.92
25.71
1.50
5.89
1.00
99.47
1.00
213.18
157.50
0.99
53.89
0.76
100.00
100.00
97.89
97.89
100.00
Range
4.32
3.64
0.69
1.50
0.36
45.72
0.86
24.43
157.5
0.31
53.88
0.88
41.00
45.00
22.65
12.38
24.78
Var
19.95
16.24
0.33
0.66
0.10
849.15
0.16
1934.4
6
768.05
0.05
24.54
0.64
825.94
872.51
425.68
334.32
385.32
Std.
Dev.
4.47
4.03
0.57
0.81
0.32
29.14
0.41
43.98
27.71
0.22
4.95
0.80
28.74
29.54
20.63
18.28
19.63
Std.
Error
0.02
0.01
0.00
0.00
0.00
0.11
0.00
0.16
0.10
0.00
0.019
0.00
0.11
0.11
0.08
0.07
0.07
56
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Appendix 9. Extent of poor-fair-good condition for indicators expressed as percent of stream length assessed (75,000 km total). Results based
on comparison of probability site data to thresholds values generated from reference sites.
Metric
Description
Poor
Fair
Good
Relative Risk Calculated?
Water Quality
SO4 MG
PTL MG
PHSVL
NTL MG
COND
CL MG
sulfate
total phosphorous
pH
nitrogen
conductivity
chloride
37
32
15
15
33
23
11
17
39
28
16
27
52
51
46
57
51
50
yes
yes
yes
yes
inadequate #sites by o-e category
inadequate #sites by o-e category
Riparian Condition
Wl HAG
Wl HALL
XPCMG
XCDENMID
riparian disturbance from agriculture
riparian disturbance all types
riparian vegetation structure
Mid-channel canopy density
29
38
13
14
5
15
19
11
66
47
69
75
yes
inadequate #sites by o-e category
yes
inadequate #sites by o-e category
In-channel Habitat Complexity
V1TM100
XFC BIG
LRBS BW5
RP100
PCT SLOW
PCT FAST
large woody debris volume
fish cover
channel stability
residual pool area
%pools+glides
% riffle+cascade+rapids+falls
17
22
16
16
2
2
20
36
32
29
12
11
63
42
52
54
86
85
yes
inadequate #sites by o-e category
yes
inadequate #sites by o-e category
inadequate #sites by o-e category
inadequate #sites by o-e category
Sediment Quantity
TSS
PCT FN
TURB
PCT SAFN
XEMBED
total suspended solids
% fines
turbidity
% sand+fines
embeddedness
18
22
24
26
27
22
18
17
26
26
60
60
58
48
47
yes
yes
yes
yes
yes
57
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Appendix 10. Estimating relative risk estimate for stressors. Data used for calculation of relative risk where A=good O/E index and Good stressor metric value,
B= poor O/E index and Good stressor metric value, C= Good O/E index and Poor stressor metric value, and D= Poor O/E index and Poor stressor metric value.
Relative risk calculated as =(D/C+D)/(B/A+B). Note: minimum of five sites in each A, B, C, D categories required to calculated relative risk (Chloride,
Temperature, and riparian Dist, and shade All were not useable).
Metric
Description
A
(site#)
C
(site#)
B
(site#)
D
(site#)
A (km)
C(km)
B(km)
D(km)
Relative
Risk
Water Quality
SO4 MG
PTL MG
PHSVL
NTL MG
COND
CL MG
sulfate
total phosphorous
pH
nitrogen
conductivity
chloride
71
68
50
81
54
67
20
17
14
10
26
12
10
10
5
10
4
3
15
8
5
9
19
17
24622
23676
24093
25314
24542
29813
7311
9158
3536
6128
7385
3662
2446
2214
2005
1884
2214
106
6570
4287
1841
1883
5054
5506
5.2
3.7
4.5
3.4
Riparian Condition
W1_HAG_R
Wl HALL R
XPCMG R
XCDENMID R
riparian disturbance from
agriculture
riparian disturbance all types
riparian vegetation structure
Mid-channel canopy density
76
47
78
87
28
35
9
8
6
4
7
16
19
18
8
4
28461
22167
29362
32569
9371
11015
4729
3305
3551
3495
1623
2714
5092
5429
3969
3566
3.2
8.7
In-channel Habitat Complexity
V1TM100 R
XFC BIG R
LRBS BW5 R
RP100 R
PCT SLOW R
PCT FAST R
large woody debris volume
fish cover
channel stability
residual pool area
%pools+glides
% riffle+cascade+rapids+falls
77
67
68
65
88
87
9
12
11
6
6
6
10
4
8
14
25
25
5
13
13
1
0
0
27514
22960
21887
20504
30969
30933
4713
4437
2530
4171
1667
1667
3750
1805
2356
5122
8241
8241
3085
5866
2711
573
0
0
3.3
5.3
Sediment Quality
TSS
PCT FN-R
TURB
PCT SAFN R
XEMBED R
total suspended solids
% fines
turbidity
% sand+fines
embeddedness
73
73
72
63
57
15
14
20
18
15
7
8
14
7
6
12
16
12
17
14
27021
30122
25891
24789
22580
4530
4423
6564
4645
4874
2677
2766
3210
1783
2034
3715
5633
5835
5514
5412
5.0
6.7
4.3
8.1
6.4
58
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