About This Map
This mapping application displays current EDT network and assessment unit data layers for the Okanogan subbasin, in addition to other planning layers such as OBMEP Survey Sites. This platform will be used over the
course of the project to display all project related spatial data and EDT output results. The control panel will be expanded and provide user-friendly tools
for comparing various management scenarios across the basin.
The stream mapping tools on the right provide a preview of a second application that will be used for refining stream reach geometry. Multiple basemap services are
loaded into this application providing multiple looks at ground conditions. The line drawing tool can also be used for measurement.
Alkalinity, or acid neutralizing capacity (ANC), is measured as milli-equivalents per liter or mg/l of either HCO3 or CaCO3. Alkalinity is broadly correlated with the productive capacity of streams, with respect to both primary production and fish production (Ptolemy 1993). Hard waters apparently tend to be more productive, though reasons for this have not been clearly established (Hynes 1972).
Alkalinity is used in EDT as a measure of stream productivity and in turn, affects 1) the maximum density that can be attained by the end of rearing life stages and 2) resulting species productivity.
Categorical Rating Definitions
0: Very low (average value typically would be 0-5 mg/l)
1: Moderately low (average value typically would be 5-10 mg/l)
2: Moderately high (average value typically would be 10-40 mg/l)
3: High (average value typically would be 40-100 mg/l)
4: Very high (average value typically would be 100-300 mg/l)
Bed Scour. Average depth of bed scour in salmonid spawning areas (i.e., in pool-tailouts and small cobble gravel riffles) during the annual peak flow event over approximately a 10-year period. Scour of bed materials during high flows can affect the survival of incubating salmonid eggs and overwintering juveniles located there (Montgomery et al. 1996). It can also affect the production of aquatic insects within streams (Hershey and Lamberti 1998).
Categorical Rating Definitions
0: Average depth of scour >0 cm and <2 cm
1: Average depth of scour >2 cm and <10 cm
2: Average depth of scour >10 cm and <18 cm
3: Average depth of scour >18 cm and <24 cm
4: Average depth of scour >24 cm and <40 cm
Despite its importance, bed scour is measured infrequently particularly at a reach scale and across an entire sub-basin. In the Chehalis River Flood Reduction Project, scour ratings for EDT have been computed from bed scour correlates that have measured data. An expert panel of geomomorphologists suggested the following correlates and relative weightings that were used to compute bed scour at a reach scale in the Chehalis River:
|
Correlates
|
Weight
|
|
Wood
|
0.85
|
| Gradient |
0.20 |
| Natural Chennel Confinement |
0.69 |
| Channel Complexity |
0.38 |
| Artificial Channel Confinement |
0.54 |
| Flow Peack Change |
0.53 |
Benthos Diversity and Production.A measure of the abundance, diversity and production of benthic macroinvertebrates that contribute to the amount of food available to juvenile salmonids. Benthic organisms in flowing waters comprise an important component of the diet of many fish species, particularly of juvenile salmonids. Food supply in turn can affect the survival of rearing fishes, as well as the maximum densities that can be achieved by these species within key habitats.
The rating scheme shown below is based on the relative abundance of mayflies (Emphemeroptera), stoneflies (Plecoptera) and caddisflies (Trichoptera). Other schemes are available, see Lestelle (2004).
Categorical Rating Definitions
0: Macroinvertebrates abundant; multiple species of families
Emphemeroptera, Plecoptera, and Trichoptera are present.
0: (1) Simple EPT index -- Macroinvertebrates abundant; multiple species of families Emphemeroptera, Plecoptera, and Trichoptera are present. OR (2) B-IBI (10 metrics) -- >=45Comparable to least disturbed reference condition; overall high taxa diversity, particularly of mayflies, stoneflies, caddisflies, long-lived clinger, and intolerant taxa. Relative abundance of predators high. OR (3) BORIS score -- Minimal impairment in benthic community - <1 standard deviation from the reference mean AND considered "ideal or good watershed and stream condition for reference condition."
1: (1) Simple EPT index -- Intermediate OR (2) B-IBI (10 metrics) -- >=37 and <45.Slightly divergent from least disturbed condition; absence of some long-lived and intolerant taxa; slight decline in richness of mayflies, stoneflies, and caddisflies; proportion of tolerant taxa increases. OR (3) BORIS score -- Minimal impairment in benthic community - <1 standard deviation from the reference mean AND considered "marginal watershed and stream condition for reference condition."
2: (1) Simple EPT index -- Macroinvertebrates common or abundant but 1-2 families among Emphemeroptera, Plecoptera, and Trichoptera are not present. OR (2) B-IBI (10 metrics) -- >=27 and <37.Total taxa reduced-particularly intolerant, long-lived, stonefly, and clinger taxa. Relative abundance of predator declines; proportion of tolerant taxa continues to increase. OR (3) BORIS score -- Moderate impairment in benthic community - >1 and <2 standard deviations from the reference mean.
3: (1) Simple EPT index -- Intermediate. OR (2) B-IBI (10 metrics) -- >=17 and <27.Overall taxa diversity depressed; proportion of predators greatly reduced as is long-lived taxa richness; few stoneflies or intolerant taxa present; dominance by three most abundant taxa often very high. OR (3) BORIS score -- Severe impairment in benthic community ->2 and <2.5 standard deviations from the reference mean.
4: (1) Simple EPT index -- Macroinvertebrates are present only at extremely low densities and/or biomass. OR (2) B-IBI (10 metrics) -- <17.Overall taxa diversity very low and dominated by a few highly tolerant taxa; mayfly, stonefly, caddisfly, clinger, long-lived and intolerant taxa largely absent. Relative abundance of predators very low. OR (3) BORIS score -- Extremely severe impairment in benthic community->2.5 standard deviations from the reference mean.
Natural Channel Confinement. The extent that the valley floodplain of the reach is confined by natural features—determined as the ratio between the width of the valley floodplain and the bankfull channel width (Montgomery and Buffington 1998). Channel confinement affects habitat-forming processes and, hence, the occurrence of different types of fish habitats within the stream network. Extent of confinement also affects water velocity and flood storage capacity of the floodplain, and, consequently it can strongly influence bed stability and potential for bed scour.
Categorical Rating Definitions
0: Reach mostly unconfined by natural features -- Average valley width > 4 channel widths.
1: Reach comprised approximately equally of unconfined and moderately confined sections.
2: Reach mostly moderately confined by natural features -- Average valley width 2 - 4 channel widths.
3: Reach comprised approximately equally of moderately confined and confined sections.
4: Reach mostly confined by natural features -- Average valley width < 2 channel widths.
Artificial Channel Confinement (Hydromodification). The extent that man-made structures within or adjacent to the stream channel constrict flow (as at bridges) or restrict flow access to the stream's floodplain (due to streamside roads, revetments, diking or levees) or the extent that the channel has been ditched or channelized, or has undergone significant streambed degradation due to channel incision/entrenchment (Beechie et al. 1994). Flow access to the floodplain can be partially or wholly cutoff due to channel incision.
Categorical Rating Definitions
0: The stream channel within the reach is essentially fully connected to its floodplain. Very minor structures may exist in the reach that do not result in flow constriction or restriction. Note: this describes both a natural condition within a naturally unconfined channel as well as the natural condition within a canyon.
1: Some portion of the stream channel, though less than 10% (of the sum of lengths of both banks), is disconnected from its floodplain along one or both banks due to man-made structures or ditching.
2: More than 10% and less than 40% of the entire length of the stream channel (sum of lengths of both banks) within the reach is disconnected from its floodplain along one or both banks due to man-made structures or ditching.
3: More than 40% and less than 80% of the entire length of the stream channel (sum of lengths of both banks) within the reach is disconnected from its floodplain along one or both banks due to man-made structures or ditching.
4: Greater than 80% of the entire length of the stream channel (sum of lengths of both banks) within the reach is disconnected from its floodplain along one or both banks due to man-made structures or ditching.
Dissolved Oxygen. Dissolved oxygen (DO) is a basic requirement for a healthy aquatic ecosystem. Fish and aquatic insects require DO to survive and carry on life giving functions.
Categorical Rating Definitions
0: > 8 mg/L (allows for all biological functions for salmonids without impairment at temperatures ranging from 0-25 C)
1: > 6 mg/L and < 8 mg/L (causes initial stress symptoms for some salmonids at temperatures ranging from 0-25 C)
2: > 4 and < 6 mg/L (stress increased, biological function impaired)
3: > 3 and < 4 mg/L (growth, food conversion efficiency, swimming performance adversely affected)
4: < 3 mg/L
Embeddedness. The extent that larger cobbles or gravel are surrounded by or covered by fine sediment, such as sands, silts, and clays. Embeddedness is determined by examining the extent (as an average %) that cobble and gravel particles on the substrate surface are buried by fine sediments. Embeddedness affects survival of non-spawning/egg stages of salmon. Juvenile fish will hide in the interstitial spaces in stream substrates, particularly in winter, when the voids are accessible. When these spaces are filled by fine sediment (embedded), the quality of the substrate for hiding cover is diminished, and survival can be reduced (Bjornn and Reiser 1991).
Categorical Rating Definitions
0: < 10% of surface covered by fine sediment.
1: > 10 and < 25 % covered by fine sediment.
2: > 25 and < 50 % covered by fine sediment.
3: > 50 and < 90 % covered by fine sediment.
4: > 90% covered by fine sediment.
Fine Sediment. Percentage of fine sediment within salmonid spawning substrates, located in pool-tailouts, glides, and small cobble-gravel riffles. Fine sediment particles within the substrate of pool-tailouts, glides, and riffles can affect the survival of incubating salmonid eggs and alevins by altering oxygen exchange across the organisms and by entombment (Bjornn and Reiser 1991).
Categorical Rating Definitions
0: Particle sizes <0.85 mm < 6% OR Particle sizes <6.3 mm: <10%
1: Particle sizes <0.85 mm: > 6% and < 11% OR Particle sizes <6.3 mm: >10% and <25%
2: Particle sizes <0.85 mm: > 11% and < 18% OR Particle sizes <6.3 mm: >25% and <40%
3: Particle sizes <0.85 mm: > 18% and < 30% OR Particle sizes <6.3 mm: >40% and <60%
4: Particle sizes <0.85 mm: > 30% fines OR Particle sizes <6.3 mm: >60%
Fish Community Richness. Measure of the richness of the fish community (no. of fish taxa, i.e., species) for native and non-native fish. Fish community richness can influence the relative magnitude of interspecific interactions, including both competition and predation effects. Generally, the diversity of fish species increases from headwaters to downstream areas within a river system (Schlosser 1991). Hence the extent of interspecific interactions (competition and predation) generally increases in a downstream direction within a river system (Reeves et al. 1998).
Categorical Rating Definitions
0: 2 or fewer fish taxa
1: 3-7 fish taxa
2: 8-17 fish taxa
3: 18-25 fish taxa
4: > 25 fish taxa
Fish Pathogens. The presence of pathogenic organisms (relative abundance and species present) having potential for affecting survival of stream fishes. Fish stocking history is assumed to be an indicator of the potential for introductions of pathogens into the system in such manner to affect the relative abundance and species of pathogenic organisms (Bartholomew 1998).
Categorical Rating Definitions
0: No historic or recent fish stocking in drainage and no known incidences of whirling disease, C. shasta, IHN, or IPN
1: Historic fish stocking, but no fish stocking records within the past decade, or sockeye population currently existing in drainage, or known incidents of viruses among kokanee populations within the watershed.
2: On-going periodic, frequent, or annual fish stocking in drainage or known viral incidents within sockeye, chinook, or steelhead populations in the watershed.
3: Operating hatchery within the reach or in the reach immediately downstream or upstream
4: Known presence of whirling disease or C. shasta within the watershed.
Fish Species Introductions. Extent of introductions of exotic fish species in the vicinity of the stream reaches under consideration. Fish species introductions are a major contributor to the decline of native fishes in many areas of the Pacific Northwest contributing to increased predation and competition with native fish species (Reeves et al. 1998).
Categorical Rating Definitions
0: No non-native species reported or known to be in the sub-drainage of interest.
1: 1-2 non-native species reported or known to be in the sub-drainage of interest.
2: 3-7 non-native species reported or known to be in the sub-drainage of interest.
3: 8-14 non-native species reported or known to be in the sub-drainage of interest.
4: 15 or more non-native species reported or known to be in the sub-drainage of interest.
Alteration of Inter-annual High Flow. The extent of relative change in average peak annual discharge compared to an undisturbed watershed of comparable size, geology, orientation, topography, and geography (or as would have existed in the pristine state). Changes in the timing and quantity of flow, due to land uses and flow regulation, can affect responses of stream dwelling organisms like salmonids, leading to changes in overall performance of their populations (Poff et al. 1997; Bunn and Arthington 2002). This attribute does not address the effect of flow on channel width or other EDT attributes. The effect of high flow on maximum channel width is incorporated in the maximum width attribute.
Note that the ratings for this attribute do not follow the typical 0 (normative)-4 (highly altered) rating scheme of EDT attributes. Instead, a rating of 2 is the normative condition and 0 and 4 represent extreme deviations from normative.
Categorical Rating Definitions
0: Peak annual flows expected to be strongly reduced relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >40% and <100% decrease in Q2yr based on a long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state) or as known by regulated flow levels. This condition is associated with flow regulation or water diversion projects.
1: Peak annual flows expected to be moderately reduced relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >20% and <40% decrease in Q2yr based on a long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state) or as known by regulated flow levels. This condition is associated with flow regulation or water diversion projects.
2: Peak annual flows expected to be comparable to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR <20% change in Q2yr based on a long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state); OR <5% reduction in average TQmean compared to the undeveloped watershed state.
3: Peak annual flows expected to be moderately increased relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >20% and <40% increase in Q2yr based on a long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state); OR >5% and <15% reduction in average TQmean compared to the undeveloped watershed state. This condition exemplified in some forested watersheds with high road density that experience significant rain on snow events, as the North Fork Stillaguamish River (Pess et al. in review). Note: many managed forested watersheds in the Pacific Northwest exhibit slight, if any, increases in peak annual flows since logging commenced (see Ziemer and Lisle 1998).
4: Peak annual flows expected to be strongly increased relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >40% and <110%+ increase in Q2yr based on a long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state); OR >15% and <45% reduction in average TQmean compared to the undeveloped watershed state. This condition exemplified in watersheds with significant urbanization (e.g., >20%).
Alteration of Inter-annual Low Flow. The extent of relative change in average daily flow during the normal low flow period compared to an undisturbed watershed of comparable size, geology, and flow regime. Changes in the timing and quantity of flow due to land uses and flow regulation can affect responses of stream dwelling organisms like salmonids, leading to changes in overall performance of their populations (Poff et al. 1997; Bunn and Arthington 2002). This attribute does not address the effect of flow on channel width or other EDT attributes. The effect of low flow on minimum channel width is incorporated in the minimum width attribute.
Note that the ratings for this attribute do not follow the typical 0 (normative)-4 (highly altered) rating scheme of EDT attributes. Instead, a rating of 2 is the normative condition and 0 and 4 represent extreme deviations from normative.
Categorical Rating Definitions
0: Average daily low flows expected to be strongly increased compared to an undisturbed watershed of similar size, geology, and flow regime (or the pristine state for the watershed of interest); OR >75% increase in the 45 or 60-day consecutive lowest average daily flow on a sufficiently long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state) or as known through flow regulation.
1: Average daily low flows expected to be moderately increased compared to an undisturbed watershed of similar size, geology, and flow regime (or the pristine state for the watershed of interest); OR >20% and <75% increase in the 45 or 60-day consecutive lowest average daily flow on a sufficiently long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state) or as known through flow regulation.
2: Average daily low flows expected to be comparable to an undisturbed watershed of similar size, geology, and flow regime (or the pristine state for the watershed of interest); OR <20% change in the 45 or 60-day consecutive lowest average daily flow on a sufficiently long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state).
3: Average daily low flows expected to be moderately reduced compared to an undisturbed watershed of similar size, geology, and flow regime (or the pristine state for the watershed of interest); OR >20% and <50% reduction in the 45 or 60-day consecutive lowest average daily flow on a sufficiently long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state) or as known through flow regulation.
4: Average daily low flows expected to be severely reduced compared to an undisturbed watershed of similar size, geology, and flow regime (or the pristine state for the watershed of interest); OR >50% and <=100% reduction in the 45 or 60-day consecutive lowest average daily flow on a sufficiently long time series (~40 yrs or longer with at least 20 yrs pertaining to a watershed development state) or as known through flow regulation.
Diel Flow Variation. Average diel variation in flow level during a season or month. This attribute is informative for rivers with hydroelectric projects or in heavily urbanized drainages where storm runoff causes rapid changes in flow. Sudden changes in flow associated with flow regulation or storm runoff can result in displacement of rearing juveniles or, in the case of loss of flow, in stranding.
Categorical Rating Definitions
0: Essentially no variation in discharge during an average 24-hr period during season or month. This characterizes conditions not influenced by flow ramping or accelerated storm runoff. This rating also would apply to small suburban-urbanized drainages with impervious surfaces of <10% in high rainfall climates (e.g., Puget Lowlands) and with little or no flow detention systems in place.
1: Slight to low variation in flow stage during an average 24-hr period during season or month. This pattern typical of routine (everyday) slight to low ramping condition associated with flow regulation, averaging <2 inches change in stage per hour. This condition has both slight to low rates of change in flow and high frequency with which it occurs. This rating also would apply to small suburban-urbanized drainages with impervious surfaces of ~10-25% in high rainfall climates (e.g., Puget Lowlands) and with little or no flow detention systems in place.
2: Low to moderate variation in flow stage during an average 24-hr period during season or month. This pattern typical of routine (everyday) low to moderate ramping condition associated with flow regulation, averaging >2 inches and <6 inches change in stage per hour. This condition has both moderate to high rates of change in flow and high frequency with which it occurs. This rating also would apply to small suburban- urbanized drainages with impervious surfaces of ~25-40% in high rainfall climates (e.g., Puget Lowlands) and with little or no flow detention systems in place.
3: Moderate to high variation in flow stage during an average 24-hr period during season or month. This pattern typical of routine (everyday) moderate to high ramping condition associated with flow regulation, averaging between 6 inches to 12 inches change in stage per hour. This condition has both moderate to high rates of change in flow and high frequency with which it occurs. This rating also would apply to small suburban to urbanized drainages with impervious surfaces of ~40-50% in high rainfall climates (e.g., Puget Lowlands) and with little or no flow detention systems in place.
4: Extreme variation in flow stage during an average 24-hr period during season or month. This pattern typical of routine (everyday) extreme ramping condition associated with flow regulation, averaging between 12 inches to 24 inches change in stage per hour. This condition is both extreme in the rate of change in flow and the frequency with which it occurs. This rating would apply to small, heavily urbanized drainages with impervious surfaces of 50-80% in high rainfall climates (e.g., Puget Lowlands) and with little or no flow detention systems in place.
Intra-Annual Flow Pattern (Flashiness). The average extent of intra-annual flow variation during the primary runoff season – in other words, the attribute is a measure of a stream's "flashiness" during storm runoff. Flashiness is correlated with percent total impervious area and road density, but is attenuated as drainage area increases. Flashiness often leads to habitat alteration and loss of species in urbanized systems especially (Booth et al. 2001).
Note that the ratings for this attribute do not follow the typical 0 (normative)-4 (highly altered) rating scheme of EDT attributes. Instead, a rating of 2 is the normative condition and 0 and 4 represent extreme deviations from normative. Ratings greater than 2 characterize systems with high levels of impervious surfaces (urbanized).
Categorical Rating Definitions
0: Storm runoff response (rates of change in flow) expected to be slowed greatly relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >15% increase in average TQmean compared to the undeveloped watershed state or as known by regulated flow levels. This condition is associated with flow regulation.
1: Storm runoff response (rates of change in flow) expected to be moderately slower relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >5% and <15% increase in average TQmean compared to the undeveloped watershed state or as known by regulated flow levels. This condition is associated with flow regulation.
2: Storm runoff response (rates of change in flow) comparable to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR <5% reduction in average TQmean compared to the undeveloped watershed state.
3: Storm runoff response (rates of change in flow) expected to be moderately increased relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >5% and <15% reduction in average TQmean compared to the undeveloped watershed state. This condition exemplified in some managed forested watersheds with high road density, likely most evident in small drainages.
4: Storm runoff response (rates of change in flow) expected to be strongly increased relative to an undisturbed watershed of similar size, geology, orientation, topography, and geography (or the pristine state for the watershed of interest); OR >15% and <45% reduction in average TQmean compared to the undeveloped watershed state. This condition exemplified in watersheds with significant urbanization.
Width. Width is a non-categorical measure in EDT entered as the average width over the length of the reach.
The average width of the reach in meters during the selected month, including the primary channel and any secondary channels but excluding off-channel areas. The upper and lower bounds for channel width are the average of the measured bankfull channel and baseflow wetted widths, respectively. Channel widths in the intervening months are interpolated between the upper and lower bound widths using the normalized pattern of mean monthly flow (TQmean) for a representative 20-year time period.
Gradient. Gradient is a non-categorical measure in EDT entered as the percent change in elevation over the length of a reach.
Channel gradient (or slope) describes how the channel's elevation changes over distance. It is an important determinant of flow velocity and sediment transport within a reach. It is a controlling factor in channel shape and pattern, and therefore in determining the types and stability of habitat within a reach. Hence it can be an important factor in controlling the overall suitability of a reach for salmonid utilization and survival.
Backwater Pool Habitat. Percentage of the wetted channel surface area comprising backwater pools (Hawkins et al. 1993). Backwater pools are habitat units located along the channel margins but are otherwise enclosed—though still connected to the main channel (or side channel). Backwater pools are located along channel margins, resulting in low water velocities through these habitat units. They often are relatively shallow with fine-grained substrates. Backwater pools are particularly important as nursery areas for fry of some salmonid species (e.g., Coho and Chinook), as well as for continued rearing during summer. They also serve as refuge areas during winter, particularly within deeper backwater pools.
Beaver Pond Habitat. Percentage of the wetted channel surface area comprising beaver ponds. Beaver ponds provide important ecological functions in riverine systems inhabited by salmonids (Burchsted et al. 2010; Castro et al. 2013). These functions include nutrient retention, sediment trapping, and amelioration of flow and temperature extremes. Beaver ponds provide habitat to salmonids, notably during juvenile life stages. Low velocities associated with this habitat type make these sites particularly preferable by some salmonid species for rearing or overwintering.
Large Cobble Riffle Habitat. Percentage of the wetted channel surface area of a reach comprising large cobble/boulder (>5 inch diameter) riffles. Substrate size associated with this habitat type is unsuited for spawning by salmonids, except that small pockets of small cobble/gravel can be interspersed within this habitat type enabling successful redd construction by salmonids. Cobble and boulders can provide cover and refugia for juvenile life stages especially in high velocity areas.
Alkalinity is used in EDT as a measure of stream productivity and in turn, affects 1) the maximum density that can be attained by the end of rearing life stages and 2) resultant species productivity.
Pool Tailout Habitat. The percentage of wetted channel surface area of a reach comprising pool tailouts defined as the mound of gravel found at the downstream end of scour pools. Tailouts are assumed in EDT to be highly utilized by salmon for spawning (Bisson et al. 1982)
Glide Habitat. Percentage of the wetted channel surface area comprising glides. There is a general lack of consensus regarding the definition of glides (Hawkins et al. 1993), despite a commonly held view that it remains important to recognize a habitat type that is intermediate between pool and riffle. The definition applied here is from the ODFW habitat survey manual (Moore et al. 1997): an area with generally uniform depth and flow with no surface turbulence, generally in reaches of < 1% gradient. The proportion of reaches characterized by glides generally decreases and the amount of large wood increases.
Scour Pool Habitat. Percentage of the wetted channel surface area composed of primary scour pools. Scour pools are often associated with riffles to create a characteristic pool-riffle sequence in streams (Hawkins et al. 1993; Montgomery and Buffington 1998). Pools are primary summer habitat for juvenile Coho and other species (Nickelson 1998; Lestelle 2007).
Small Cobble Riffle Habitat. Percentage of wetted channel surface area comprised of small cobble/gravel riffles (0.2-5 inches in diameter). Small cobble riffles are often associated with scour pools to create a characteristic pool-riffle sequence in streams. Riffles, along with pool tailouts are key spawning habitat for salmonids (Bjornn and Reiser 1991; Hawkins et al. 1993).
Hatchery Fish Outplants. The amount of juvenile hatchery fish outplants into a stream in the last 10 years. The attribute only describes releases of juvenile fish. Hatchery fish released into streams can affect the performance of co-mingled wild fish through competition, predation, disease and inter-breeding (recent reviews by Paquet et al. 2011; Flagg 2015). Adverse effects through such interactions can occur during juvenile rearing, smolt, spawning, and incubation life stages.
Categorical Rating Definitions
0: No stocking records in the past decade.
1: No more than two instances of fish releases in the past decade in the drainage.
2: Fish releases made into the drainage every 1-3 years at isolated locations within the drainage.
3: Fish releases made at multiple sites in the drainage, but only in 1-3 years during the past decade. When the species released is the same as focus species, chance for some superimposition can occur here.
4: Fish releases made every 1-3 years and at multiple sites in the drainage. When the species released is the same as focus species, superimposition can occur here.
Natural Hydrologic Regime. The type and origin of natural flow in a watershed. Hydrologic regime has important impacts on stream characteristics and biota (Naiman 1998). The source of flow also has an impact on how climate change may alter stream habitats (Mantua et al. 2010).
Categorical Rating Definitions
0: Groundwater-source-dominated; strongly buffered peak flows (as in a springbrook or in river like the Metolius in central Oregon)
1: Spring snowmelt dominated, non-glacial; temporally consistent and moderate peak and low flows
2: Rain-on-snow transitional; consistent spring peak and low flows with inconsistent and flashy winter or early spring rain-on-snow peaks
3: Rainfall-dominated; flashy winter and early spring peaks, consistently low summer flows and variable spring and fall flows.
4: Glacial runoff system; high, turbid low flows, generally buffered peak flows except with occasional outburst floods and infrequent rain-on-snow events
Regulated Flow Regime. Amount of artificial flow regulation caused by dams, irrigation or other actions. This attribute does not take into account daily flow fluctuations that are incorporated in other flow attributes.
Categorical Rating Definitions
0: No artificial flow regulation occurs upstream to affect hydrograph.
1: Project operations have not changed median flows between months or season as the project is operated as a run-of-river facility, or project storage is < 15 days of the annual mean daily flow of the river.
2: Project operations have not changed median flows between months or season as the project is operated as a run-of-river facility, or project storage is > 15 and < 30-days of the annual mean daily flow of the river.
3: Project operations have resulted in a measurable shift in median flows between months or seasons. The project provides limited flood control during periods of high run-off (winter or spring). The projects reservoir is operated each year to store more than 30 but less than 60-days of the annual mean daily flow of the river.
4: Project operations have resulted in a major shift in median flows between months or seasons. The project is operated to provide significant flood control during high run-off periods (winter or spring). The projects reservoir is operated each year to store more than 60-days of the annual mean daily flow of the river.
Miscellaneous Pollutants in Water Column. The extent of non-metal pollutants in the water column. Among the most common pollutants found in contaminated streams are petroleum hydrocarbon compounds, pesticides, herbicides and industrial chemicals.
Categorical Rating Definitions
0: No substances present that may periodically be at or near chronic toxicity levels to salmonids.
1: One substance present that may only periodically rise to near chronic toxicity levels (may exert some chronic toxicity) to salmonids.
2: More than one substance present that may periodically rise to near chronic toxicity levels or one substance present > chronic threshold and < acute threshold (consistently chronic toxicity) to salmonids.
3: One or more substances present > acute toxicity threshold but < 3X acute toxicity threshold (usually acutely toxic) to salmonids.
4: One or more substances present with > 3X acute toxicity (always acutely toxic) to salmonids.
Nutrient Enrichment. The extent of nutrient enrichment (most often by either nitrogen or phosphorous or both) from anthropogenic activities. Nitrogen and phosphorous are the primary macro-nutrients that enrich streams and cause build ups of algae. These conditions, in addition to leading to other adverse conditions, such as low DO can be indicative of conditions that are unhealthy for salmonids.
Categorical Rating Definitions
0: Unenriched streams (corresponding to benthic chlorophyll a values 0.5-3 mg/m2). Nutrient levels typical of oligotrophic conditions (small supply of nutrients, low production of organic matter, low rates of decomposition, and high DO). No enrichment is occurring nor is suspected. Green filamentous algae may be present at certain times of year, particularly in unshaded areas.
1: Very small amount of enrichment suspected to be occurring through land use activities (corresponding to benthic chlorophyll a values 3-20 mg/m2). Green filamentous algae present in summer months in unshaded reaches.
2: Nutrient levels typical of oligotrophic conditions (small supply of nutrients, low production of organic matter, low rates of decomposition, and high DO). Some enrichment known to be occurring (corresponding to benthic chlorophyll a values 20-60 mg/m2), often associated with failing skeptics tanks or runoff from areas of heavy fertilizer usage. Dense mats of green or brown filamentous algae present in summer months.
3: Euthrophic (abundant nutrients associated with high level of primary production, frequently resulting in oxygen depletion).Very obvious enrichment of reach is occurring from point sources or numerous non-point sources (corresponding to benthic chlorophyll a values 60-600 mg/m2). Large, dense mats of green or brown filamentous algae will be present during summer months.
4: Super enrichment of reach is strongly evident. Known, major point sources of organic waste inputs, such as runoff from large feedlot operation, wash water from farm products processing, or significant sewage facilities with inadequate treatment (corresponding to benthic chlorophyll a values 600-1200 mg/m2). In most severe cases, filamentous bacteria abundant, associated with low D.O. and hydrogen sulfide. In less severe cases, large dense mats of green or brown filamentous algae generally cover the substrate.
Predator Concentrations. Increased risk of predation (above what would be expected under normative conditions) caused by unusual concentration of predators due to man-made structures. Construction of dams, outfalls or other structures can provide enhanced predation opportunities for native and non-native predatory fishes, birds and other species.
Note that the ratings for this attribute do not follow the typical 0 (normative)-4 (highly altered) rating scheme of EDT attributes. Instead, a rating of 2 is the normative condition and 0 and 4 represent extreme deviations from normative.
Categorical Rating Definitions
0: Many or most native predators are depressed or rare, none are greatly increased over natural levels, and there is expected a significant numerical survival advantage to fish as a result compared to historical predator abundance.
1: Some native predators are moderately depressed, none are greatly increased over natural levels, and there is expected some small to moderate numerical survival advantage to fish as a result compared to historical predator abundance.
2: Diversity and per-capita abundance of predators exists so that predation risk is at near-natural level and distribution.
3: Moderate increase in population density or moderately concentrated population of predator species exists due to artifacts of human alteration of the environment (e.g., top-down food web effects, habitat manipulations) compared to historical condition.
4: Excessive population density or concentrated population of predator species exists due to artifacts of human alteration of the environment (e.g., top-down food web effects, habitat manipulations) compared to historic condition.
Riparian Function. This attribute addresses the alteration of the riparian zone at a reach scale. The riparian corridor along a stream is characterized by its vegetation—trees, brush, grass, and sedges. The zone comprises those areas near the stream channel that affect the channel and are affected by it. Riparian areas create connections between aquatic and terrestrial environments and provide a number of important ecological functions including temperature, food, channel structure stream-floodplain connectivity (Naiman et al. 1998; Gregory et al. 2002; McConnaha et al. 2016). Several of these functions are addressed in specific EDT attributes such as large wood and temperature. The Riparian Function attribute specifically addresses the extent of linkage between the stream and the floodplain and riparian services not captured in other attributes (e.g. LWD).
Categorical Rating Definitions
0: Strong linkages with no anthropogenic influences.
1: >75-90% of functional attributes present (overbank flows, vegetated streambanks, groundwater interactions typically present).
2: 50-75% functional attribute rating- significant loss of riparian functioning- minor channel incision, diminished riparian vegetation structure and inputs etc.
3: 25-50% similarity to natural conditions in functional attributes- many linkages between the stream and its floodplain are severed.
4: < 25% functional attribute rating: complete severing of floodplain-stream linkages
Salmon Carcasses. Relative abundance of anadromous salmonid carcasses within watershed that can serve as nutrient sources for juvenile salmonid production and other organisms. Salmon act as an ecological process vector, important in the transport of energy and nutrients between the ocean, estuaries, and freshwater environments (Cederholm et al. 2001; Wipfli et al. 2003). Salmon serve to cycle nutrients between these environments, most notably from the ocean to freshwater, where the carcasses can be the source of large amounts of nutrients to the riparian-stream system (Bilby et al. 2003). The carcasses provide food to numerous wildlife species, macroinvertebrates, and fish species, including juvenile salmonids.
Categorical Rating Definitions
0: Super abundant -- average number of carcasses per mile of main channel habitat (within an appropriately designated area) >800.
1: Very abundant -- average number of carcasses per mile of main channel habitat (within an appropriately designated area) >400 and < 800.
2: Moderately abundant -- average number of carcasses per mile of main channel habitat (within an appropriately designated area) >200 and < 400.
3: Not abundant -- average number of carcasses per mile of main channel habitat (within an appropriately designated area) >25 and <200.
4: Very few or none -- average number of carcasses per mile of main channel habitat (within an appropriately designated area) <25.
Temperature Daily Maximum. Maximum water temperatures within the stream reach during a month. EDT ratings for this attribute are designed to characterize the potential exposure of fish to thermal conditions across a month based on EPA criteria developed by McCullough et al. (2001). Water temperature is a crucial physiological factor affecting salmonid survival and many ecological processes within aquatic environments. It has a key role in shaping ecological structure and function along the river continuum. Fish species can tolerate only a limited range of temperature, which places distinct limits on fish distribution and performance (Bjornn and Reiser 1991). Shifts in maximum and minimum temperatures within the stream can have profound effects on species composition of both vertebrates and invertebrates.
Categorical Rating Definitions
0: Warmest day < 10 C
1: Warmest day>10 C and <16 C
2: > 1 d with warmest day 22-25 C or 1-12 d with >16 C
3: > 1 d with warmest day 25-27.5 C or > 4 d (non-consecutive) with warmest day 22-25 C or >12 d with >16 C
4: > 1 d with warmest day 27.5 C or 3 d (consecutive) >25 C or >24 d with >21 C
Temperature Daily Minimum. Minimum water temperatures within the stream reach during a month. Stream-dwelling salmonids can survive at temperatures near the extremes of suitable range, but growth and subsequent survival can be reduced at low temperatures (< 4°C) because all metabolic processes are slowed.
Categorical Rating Definitions
0: Coldest day >4 C
1: < 7 d with <4 C and minimum > 1 C
2: 1 to 7 d < 1 C
3: 8 to 15 days < 1 C
4: > 15 winter days < 1 C
Temperature Spatial Variation. The extent of water temperature variation (cool or warm water depending upon season) within the reach as influenced by inputs of groundwater or tributary streams, or the presence of thermally stratified deep pools. These areas provide refugia for salmon and moderate the effect of high temperatures (Torgersen et al. 1999; Sutton and Soto 2012).
Categorical Rating Definitions
0: Groundwater discharge into surface waters is the major source of flow in reach.
1: Abundant sites of groundwater discharge into surface waters.
2: Intermittent sites of groundwater discharge into surface waters and total quantity of groundwater discharge not a major source of flow in reach.
3: Infrequent sites of groundwater discharge into surface waters and total quantity of groundwater discharge not a major source of flow in reach.
4: No evidence of concentrated groundwater inputs.
Suspended Sediment (Turbidity). The severity of suspended sediment (SS) episodes within the stream reach. Suspended solids represents the actual measure of mineral and organic particles transported in the water column, either expressed as total suspended solids (TSS) or suspended sediment concentration (SSC)—both as mg/l. Technically, turbidity is not suspended sediment, but the two are usually well correlated. Quantitative EDT ratings are based on Scale of Severity (SEV) Index taken from Newcombe and Jensen (1996) and discussed in Lestelle (2004).
Categorical Rating Definitions
0: SEV Index <= 4.5 Clear with infrequent (short duration-- several days per year) concentrations of low concentrations (< 50 mg/l) of suspended sediment. No adverse effects on biota of these low doses.
1: SEV Index >4.5 and <= 7.5 Occasional episodes (days) of low to moderate concentrations (<500 mg/L), though very short duration episodes (hours) may occur with of higher concentrations (500 to 1000). These concentrations are always sublethal to juvenile and adult salmonids-though some behavioral modification may occur.
2: SEV Index >7.5 and <= 10.5 Occasional episodes of moderate to relatively high concentrations (>500 and <1000 mg/L), though shorter duration episodes (<1 week) may occur with higher concentrations (1000-5000 mg/L). The higher concentrations stated can be expected to result in major behavioral modification, severe stress, severely reduced forage success and direct mortality.
3: SEV Index >10.5 and <= 12.5 On-going or occasional episodes (periodic events annually lasting weeks at a time) of high concentrations of suspended sediment (>5000 and <10000 mg/L), or shorter duration episodes lasting hours or days of higher concentrations. These conditions result in direct, high mortality rates.
4: SEV Index >12.5 Extended periods (month) of very high concentrations (>10000 mg/L). These represent the most extreme severe conditions encountered and result in very high mortality of fish species.
Water Withdrawals (Entrainment). The number and relative size of water withdrawals in the stream reach. This attribute identifies risk of fish species being entrained or injured by screening or other structures associated with withdrawals of water from stream courses. The impact that water withdrawals have on flow is captured in flow attributes.
Categorical Rating Definitions
0: No withdrawals.
1: Very minor water withdrawals with or without screening (entrainment probability considered very low).
2: Several of significant water withdrawals along reach though all sites known or believed to be screened with effective screening devices. (Note: one site that withdraws substantial portion of flow without screening falls into this category.)
3: Several sites of significant water withdrawals along reach without screening or screening believed to be ineffective. (Note: one site that withdraws substantial portion of flow without screening falls into this category.)
4: Frequent sites of significant water withdrawals along reach without screening or screening believed to be ineffective.
Wood (LWD). The amount of wood (large woody debris or LWD) within the reach. Dimensions of what constitutes LWD are defined here as pieces > 0.1 m diameter and > 2 m in length. Large woody debris is an important structural component of many riverine ecosystems in the Pacific Northwest (Beechie and Sibley 1997; Bilby and Bisson 1998; Roni et al. 2014; McConnaha et al. 2016). It has key functions in forming channel type and habitat units, particularly in the creation and maintenance of pools, side channels, and backwaters. It provides structural complexity and cover for fish habitat. Wood regulates the transport of sediment, gravel, and organic matter, influencing their effects within physical and biological processes. The ability of large wood to perform these functions depends in part on its abundance, size, and type of wood, and on the size and geomorphology of the stream system.
Quantitative descriptions of EDT ratings for large wood can be found in Lestelle (2004)
Categorical Rating Definitions
0: A complex mixture of single large pieces and accumulations consisting of all sizes, decay classes, and species origins; cross-channel jams are present where appropriate vegetation and channel conditions facilitate their existence; large wood pieces are a dominant influence on channel diversity (e.g., pools, gravel bars, and mid-channel islands) where channel gradient and flow allow such influences. Density of LWD (pieces per channel width CW) consistent with the following: channel width <25 ft -- 3-10 pieces/CW, 25-50 ft -- 3-10 pieces/CW, 50-150 ft -- 7-30 pieces/CW , 150-400 ft -- 20-50 pieces/CW in conjunction with large jams in areas where accumulations might occur, >400 ft -- 15-37 pieces/CW in conjunction with large jams in areas where accumulations might occur.
1: Complex array of large wood pieces but fewer cross channel bars and fewer pieces of sound large wood due to less recruitment than index level 1; influences of large wood and jams are a prevalent influence on channel morphology where channel gradient and flow allow such influences. Density of LWD (pieces per channel width CW) consistent with the following: channel width <25 ft -- 2-3 pieces/CW, 25-50 ft -- 2-4 pieces/CW, 50-150 ft -- 3-7 pieces/CW , 150-400 ft -- 10-20 pieces/CW (excluding large jams) in conjunction with large jams in areas where accumulations might occur, >400 ft -- 8-15 pieces/CW (excluding large jams) in conjunction with large jams in areas where accumulations might occur.
2: Few pieces of large wood and their lengths are reduced and decay classes older due to less recruitment than in index level 1; small debris jams poorly anchored in place; large wood habitat and channel features of large wood origin are uncommon where channel gradient and flow allow such influences. Density of LWD (pieces per channel width CW) consistent with the following: channel width <25 ft -- 1-2 pieces/CW, 25-50 ft -- 1-2 pieces/CW, 50-150 ft -- 1-3 pieces/CW , 150-400 ft -- 10-20 pieces/CW without large jams in areas where accumulations might occur, >400 ft -- 8-15 pieces/CW without large jams in areas where accumulations might occur.
3: Large pieces of wood rare and the natural function of wood pieces limited due to diminished quantities, sizes, decay classes and the capacity of the riparian streambank vegetation to retain pieces where channel gradient and flow allow such influences. Density of LWD (pieces per channel width CW) consistent with the following: channel width <25 ft -- 0.33-1 pieces/CW, 25-50 ft -- 0.33-1 pieces/CW, 50-150 ft -- 0.33-1 pieces/CW , 150-400 ft -- 3-10 pieces/CW without large jams in areas where accumulations might occur, >400 ft -- 2-8 pieces/CW without large jams in areas where accumulations might occur.
4: Pieces of LWD rare. Density of LWD (pieces per channel width CW) consistent with the following: channel width <25 ft -- <0.33 pieces/CW, 25-50 ft -- <0.33 pieces/CW, 50-150 ft -- <0.33 pieces/CW , 150-400 ft -- <3 pieces/CW with accumulations where they might occur, >400 ft -- <2 pieces/CW with no accumulations where they might occur.
Off Channel Habitat Factor. A multiplier used to estimate the amount of off-channel habitat based on the wetted surface area of the all combined in-channel habitat.
