Limiting Factors



Intermountain Province

Coeur d' Alene Subbasin 408, 409

BULL TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Agricultural Practices; Urbanization Migration Impediments Juveniles, adults A barrier at the mouth of Little North Fork prevents trout from entering the stream. In addition, improperly graded culverts exist in Pedee Creek as well as man-made barriers in Benewah, Pedee, Plummer, Fighting, and Lake creeks. Artificial barriers exist throughout most of the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation Juveniles, adults Lack of habitat diversity exists throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Channel stability and habitat are degraded by road construction activities. Road densities in the Coeur d’Alene watershed are classified as high to very high.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Illegal Harvest; Harvest Adults Low compliance with harvest regulations in the Coeur d’Alene watershed is problematic. Populations are subject to high levels of legal harvest.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Non-native species introductions have lead to community shifts, predation issues, and problems with hybridization with native species.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Urbanization; Mining Activities Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Increased sediment levels exist throughout the subbasin. Sources of sedimentation include road construction and mining activities.
Toxic Contaminants Water; Biota -- Mining Activities; Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Increased chemicals/metals (from historical mining), nutrients, and bacteria are issues that exist throughout the subbasin. Concentrations of metals, due to past mining activities, is a significant problem in the South Fork Coeur d’Alene River Watershed. Heavy metal laden sediments have resulted in altered benthic invertebrate communities.
Water Quality Temperature -- Agricultural Practices; Urbanization Water: Temperature and Gas Alteration All Elevated temperatures and decreased oxygen levels exist throughout the subbasin.
Water Quantity Decreased Water Quantity -- Dam or Hydropower Facility Management Water: Storage or Withdrawal All Reduced flows exist throughout the subbasin. Operations of Post Falls dam increase the slack water habitat in lower portions of the St. Joe River and increase habitat in Coeur d’Alene Lake that is more suitable for exotic fish species.
WESTSLOPE CUTTHROAT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Fishery Management Species Introduction Adults Non-native rainbow trout releases lead to hybridization with cutthroat trout.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Agricultural Practices; Urbanization Migration Impediments Juveniles, adults A barrier at the mouth of Little North Fork prevents trout from entering the stream. In addition, improperly graded culverts exist in Pedee Creek as well as man-made barriers in Benewah, Pedee, Plummer, Fighting, and Lake creeks. Artificial barriers exist throughout most of the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation Juveniles, adults Lack of habitat diversity exists throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Channel stability and habitat are degraded by road construction activities. Road densities in the Coeur d’Alene watershed are classified as high to very high.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Non-native species introductions have lead to community shifts, predation issues, and problems with hybridization with native species.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Urbanization; Mining Activities Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Increased sediment levels exist throughout the subbasin. Sources of sedimentation include road construction and mining activities.
Toxic Contaminants Water; Biota -- Mining Activities; Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Increased chemicals/metals (from historical mining), nutrients, and bacteria are issues that exist throughout the subbasin. Concentrations of metals, due to past mining activities, is a significant problem in the South Fork Coeur d’Alene River Watershed. Heavy metal laden sediments have resulted in altered benthic invertebrate communities.
Water Quality Temperature -- Agricultural Practices; Urbanization Water: Temperature and Gas Alteration All Elevated temperatures and decreased oxygen levels exist throughout the subbasin.
Water Quantity Decreased Water Quantity -- Dam or Hydropower Facility Management Water: Storage or Withdrawal All Reduced flows exist throughout the subbasin. Operations of Post Falls dam increase the slack water habitat in lower portions of the St. Joe River and increase habitat in Coeur d’Alene Lake that is more suitable for exotic fish species.

Columbia Upper Subbasin 408

Burbot
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Small-scale structural complexity; Morphological changes Freshwater Dam and hydropower facility management Water: Storage or withdrawal Juveniles, adults Severe fluctuations of reservoir elevation frequently changes the littoral zone, limiting productivity. The lack of stable littoral habitats has resulted in virtually no macrophyte communities and severely depressed benthic macroinvertebrate communities.
Instantaneous Mortality Predation - Fishery management Species introductions Juveniles and adults Walleye and smallmouth bass introductions have lead to community shifts and predation issues.
Toxic Vontaminants Water: Biota - Mining Activities; Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Trace-element contamination is known to be widespread throughout Lake Roosevelt. recent studies report that Lake Roosevelt bed sediments are contaminated with high concentrations of trace elements, and that these high levels are impairing benthic invertebrate communities. The trace-elements have been linked to a smelter in Canada.
Water Quality Oxygen - Dam or hydrofacility management Water: Temperature and gas alteration Juveniles; adults Spillling at upriver reservoirs creates total dissolved gas levels in Lake Roosevelt that exceed state standards.
Water Quantity Altered flow timing - Dam or hydrofacility management Water: Storage or withdrawal Juveniles and adults The most significant limiting factor affecting fish in Lake Roosevelt is pool elevation fluctuations that result from hydro-operations. Due to a short water retention time (8-65 days), there is a lack of stratification during the summer that results in limited refugia of preferred temperature areas. Hydro-operations that reduce water retention time also reduce food availability for fish and reduce fish carrying capacity of the reservoir.
KOKANEE
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Dams obstruct fish migrations throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Severe fluctuations of reservoir elevation frequently changes the littoral zone, limiting productivity. The lack of stable littoral habitats has resulted in virtually no macrophyte communities and severely depressed benthic macroinvertebrate communities.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Entrainment of kokanee at Grand Coulee Dam limits the fishery in Lake Roosevelt.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Increased sediment loads, altered seasonal water regimes, and destabilized streambanks affect water quality and limit productivity in the Kettle and Colville rivers.
Water Quality Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration Juveniles, adults Spillling at upriver reservoirs creates total dissolved gas levels in Lake Roosevelt that exceed state standards.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults The most significant limiting factor affecting fish in Lake Roosevelt is pool elevation fluctuations that result from hydro-operations. Due to a short water retention time (8-65 days), there is a lack of stratification during the summer that results in limited refugia of preferred temperature areas. Hydro-operations that reduce water retention time also reduce food availability for fish and reduce fish carrying capacity of the reservoir. Natural kokanee production is limited due to annual drawdowns that expose shoreline redds.
REDBAND TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Fishery Management Species Introduction Adults Non-native rainbow trout releases lead to hybridization with native redband trout.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Dams obstruct fish migrations throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Severe fluctuations of reservoir elevation frequently changes the littoral zone, limiting productivity. The lack of stable littoral habitats has resulted in virtually no macrophyte communities and severely depressed benthic macroinvertebrate communities.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Entrainment of kokanee at Grand Coulee Dam limits the fishery in Lake Roosevelt.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Non-native species introductions have lead to community shifts, predation issues, and problems with hybridization with native species.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Increased sediment loads, altered seasonal water regimes, and destabilized streambanks affect water quality and limit productivity in the Kettle and Colville rivers.
Water Quality Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration Juveniles, adults Spillling at upriver reservoirs creates total dissolved gas levels in Lake Roosevelt that exceed state standards.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults The most significant limiting factor affecting fish in Lake Roosevelt is pool elevation fluctuations that result from hydro-operations. Due to a short water retention time (8-65 days), there is a lack of stratification during the summer that results in limited refugia of preferred temperature areas. Hydro-operations that reduce water retention time also reduce food availability for fish and reduce fish carrying capacity of the reservoir. Natural kokanee production is limited due to annual drawdowns that expose shoreline redds.
White Sturgeon
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat quantity and quality Small-scale structural complexity; Morphological changes Freshwater Dam and hydropower facility management Water: Storage or withdrawal Juveniles, adults Severe fluctuations of reservoir elevation frequently changes the littoral zone, limiting productivity. The lack of stable littoral habitats has resulted in virtually no macrophyte communities and severely depressed benthic macroinvertebrate communities.
Instantaneous Mortality Predation -- Fishery management Species introductions Juveniles; adults Walleye and smallmouth bass introductions have lead to community shifts and predation issues.
Toxic contaminants Water: Biota -- Mining Activities; Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Trace-element contamination is known to be widespread throughout Lake Roosevelt. recent studies report that Lake Roosevelt bed sediments are contaminated with high concentrations of trace elements, and that these high levels are impairing benthic invertebrate communities. The trace-elements have been linked to a smelter in Canada.
Water Quality Oxygen -- Dam or hydrofacility management Water: Temperature and gas alteration Juveniles, adults Spillling at upriver reservoirs creates total dissolved gas levels in Lake Roosevelt that exceed state standards.
Water Quantity Altered flow timing -- Dam or hydrofacility management Water: Storage or withdrawal Juveniles and adults The most significant limiting factor affecting fish in Lake Roosevelt is pool elevation fluctuations that result from hydro-operations. Due to a short water retention time (8-65 days), there is a lack of stratification during the summer that results in limited refugia of preferred temperature areas. Hydro-operations that reduce water retention time also reduce food availability for fish and reduce fish carrying capacity of the reservoir.

Pend Orielle Subbasin 408, 410, 411

BULL TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Agricultural Practices; Forest Management; Urbanization Migration Impediments Juveniles, adults Hydro dams lack passage facilities. Loss of connectivity due to artificial barriers (e.g., impassable culverts, splashdams, etc) without passage facilities on the mainstem Pend Oreille River and its tributaries limits abundance.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Diking; Filling; Riparian Degradation Juveniles, adults Diking in Pend Oreille River tributaries limits production. Lack of habitat diversity limits production in the Lower Pend Oreille. The availability of tributary spawning and rearing habitat limits salmonid production in Upper Priest Lake and Priest Lake. Tributary habitat throughout the subbasin is characterized by excess bedload filling in pools, widening of stream channels, loss of large woody debris recruitment, and fine sediment covering spawning gravels.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Diking; Filling; Wetland Loss; Riparian Degradation Juveniles, adults Livestock grazing, timber harvest, and conversion of forest lands to agriculture and residential areas have degraded riparian habitat.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Non-native species introductions have lead to community shifts, predation issues, and problems with hybridization with native species.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Mass Wasting; Forest Management; Urbanization Landslides; Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Sediment input (mass wasting and point and non-point input) due to timber harvest practices and road construction/maintenance are problems in tributaries throughout the subbasin.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Elevated temperature, dissolved oxygen, and total dissolved gases are problematic for fish in the Lower Pend Oreille.
Water Quantity Altered Flow Timing; Decreased Water Quantity -- Dam or Hydropower Facility Management; Agricultural Practices; Urbanization Water: Storage or Withdrawal All Hydropower development and operations on the Pend Oreile River altered the hydrology of the river from a cold fast-moving river to warm and shallow reservoirs. Operation of Cabinet Gorge Dam compromises riverine habitat in the Lower Clark Fork River. Water diversion in Pend Oreille River tributaries limits production.
KOKANEE
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Non-native species introductions have lead to community shifts, predation issues, and problems with hybridization with native species.
Water Quantity Altered Flow Timing; Decreased Water Quantity -- Dam or Hydropower Facility Management; Agricultural Practices; Urbanization Water: Storage or Withdrawal Eggs Hydropower development and operations on the Pend Oreile River altered the hydrology of the river from a cold fast-moving river to warm and shallow reservoirs. Operation of Cabinet Gorge Dam compromises riverine habitat in the Lower Clark Fork River. Water diversion in Pend Oreille River tributaries limits production.
LARGEMOUTH BASS
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles Lack of over-wintering habitat is the primary limiting factor.
MOUNTAIN WHITEFISH
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Migration Impediments Juveniles, adults Loss of connectivity due to artificial barriers (e.g., impassable culverts, splashdams, etc) without passage facilities on the mainstem Pend Oreille River and its tributaries limits abundance.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Diking; Filling; Riparian Degradation Juveniles, adults Diking in Pend Oreille River tributaries limits production. Lack of habitat diversity limits production in the Lower Pend Oreille. The availability of tributary spawning and rearing habitat limits salmonid production in Upper Priest Lake and Priest Lake. Tributary habitat throughout the subbasin is characterized by excess bedload filling in pools, widening of stream channels, loss of large woody debris recruitment, and fine sediment covering spawning gravels.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Diking; Filling; Wetland Loss; Riparian Degradation Juveniles, adults Livestock grazing, timber harvest, and conversion of forest lands to agriculture and residential areas have degraded riparian habitat.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Mass Wasting; Forest Management; Urbanization Landslides; Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Sediment input (mass wasting and point and non-point input) due to timber harvest practices and road construction/maintenance are problems in tributaries throughout the subbasin.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Elevated temperature, dissolved oxygen, and total dissolved gases are problematic for fish in the Lower Pend Oreille.
Water Quantity Altered Flow Timing; Decreased Water Quantity -- Agricultural Practices; Urbanization Water: Storage or Withdrawal All Water diversion in Pend Oreille River tributaries limits production.
WESTSLOPE CUTTHROAT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Fishery Management Species Introduction Adults Non-native rainbow trout releases lead to hybridization with native cutthroat trout.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Agricultural Practices; Forest Management; Urbanization Migration Impediments Juveniles, adults Hydro dams lack passage facilities. Loss of connectivity due to artificial barriers (e.g., impassable culverts, splashdams, etc) without passage facilities on the mainstem Pend Oreille River and its tributaries limits abundance.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Diking; Filling; Riparian Degradation Juveniles, adults Diking in Pend Oreille River tributaries limits production. Lack of habitat diversity limits production in the Lower Pend Oreille. The availability of tributary spawning and rearing habitat limits salmonid production in Upper Priest Lake and Priest Lake. Tributary habitat throughout the subbasin is characterized by excess bedload filling in pools, widening of stream channels, loss of large woody debris recruitment, and fine sediment covering spawning gravels.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Diking; Filling; Wetland Loss; Riparian Degradation Juveniles, adults Livestock grazing, timber harvest, and conversion of forest lands to agriculture and residential areas have degraded riparian habitat.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Non-native species introductions have lead to community shifts, predation issues, and problems with hybridization with native species.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Mass Wasting; Forest Management; Urbanization Landslides; Impervious Surfaces (Road Density); Sediment: Bank Destabilization All Sediment input (mass wasting and point and non-point input) due to timber harvest practices and road construction/maintenance are problems in tributaries throughout the subbasin.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Elevated temperature, dissolved oxygen, and total dissolved gases are problematic for fish in the Lower Pend Oreille.
Water Quantity Altered Flow Timing; Decreased Water Quantity -- Dam or Hydropower Facility Management; Agricultural Practices; Urbanization Water: Storage or Withdrawal All Hydropower development and operations on the Pend Oreile River altered the hydrology of the river from a cold fast-moving river to warm and shallow reservoirs. Operation of Cabinet Gorge Dam compromises riverine habitat in the Lower Clark Fork River. Water diversion in Pend Oreille River tributaries limits production.

Sanpoil Subbasin 408

KOKANEE
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Urbanization Migration Impediments Juveniles, adults Chief Joseph and Grand Coulee dams, both of which lack fish passage facilities, prevent upriver migrations and negatively impact downriver migration. Resident fish emigrating downstream are entrained and are unable to return to the subbasin. Major barriers (i.e., culverts) exist along State Highway 21 blocking most Westside streams to fish migration except the West Fork of the San Poil River and the North and South Nanamkin creeks.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Embedded substrate and reduced habitat complexity, due to anthropogenic activities, limits native salmonid populations.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles, adults Channel stability is decreased because of cleared riparian areas.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation All Decreased channel stability from cleared riparian areas and high road densities combine to create fine sediment issues throughout the subbasin.
Water Quality Temperature; Oxygen -- Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Water: Storage or Withdrawal All Oxygen and temperature conditions are impaired throughout the subbasin due to forest management practices and water diversions.
Water Quantity Decreased Water Quantity -- Agricultural Practices; Forest Management Water: Storage or Withdrawal All Low flows exist throughout the subbasin due to forest management practices and water diversions.
REDBAND TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Fishery Management Species Introduction Adults Non-native rainbow trout releases lead to hybridization with native redband trout.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Urbanization Migration Impediments Juveniles, adults Chief Joseph and Grand Coulee dams, both of which lack fish passage facilities, prevent upriver migrations and negatively impact downriver migration. Resident fish emigrating downstream are entrained and are unable to return to the subbasin. Major barriers (i.e., culverts) exist along State Highway 21 blocking most Westside streams to fish migration except the West Fork of the San Poil River and the North and South Nanamkin creeks.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Embedded substrate and reduced habitat complexity, due to anthropogenic activities, limits native salmonid populations.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles, adults Channel stability is decreased because of cleared riparian areas.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation All Decreased channel stability from cleared riparian areas and high road densities combine to create fine sediment issues throughout the subbasin.
Water Quality Temperature; Oxygen -- Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Water: Storage or Withdrawal All Oxygen and temperature conditions are impaired throughout the subbasin due to forest management practices and water diversions.
Water Quantity Decreased Water Quantity -- Agricultural Practices; Forest Management Water: Storage or Withdrawal All Low flows exist throughout the subbasin due to forest management practices and water diversions.

Spokane Subbasin 408

KOKANEE
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Juveniles, adults The development of hydropower facilities without fish passage facilities limits genetic exchange, distribution, and habitat connectivity for fish species.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Embedded substrate and reduced habitat complexity, due to anthropogenic activities, limits native salmonid populations.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation All Fine sediment is the most common problem throughout the watershed.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Excessive nutrients exist in the Spokane River below Spokane Falls providing conditions for aquatic vegetation to thrive in low velocity habitats. Accumulation of decaying aquatic vegetation creates biological oxygen demands exacerbating already low oxygen concentrations. dissolved oxygen levels fall below 4 mg/L in the summer.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management; Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Water: Storage or Withdrawal; Water: Temperature and Gas Alteration All In the Spokane River above Spokane Falls, increased water temperature and low dissolved oxygen concentrations are on the 303(d) list. High levels of total dissolved gas is a major problem below Long Lake Dam. Due to the continual series of reservoirs, dissolved gas cannot reach equilibrium. Approximately half of the Little Spokane drainage has impaired water quality throughout the year. Water quality in Hangman Creek is generally poor and state standards for fecal coliform, temperature, pH, and dissolved oxygen are often not met. In Upper Hangman Creek, low dissolved oxygen, high levels of total suspened solids, and high temperatures impair stream conditions and salmonid distribution. During the spring, total dissolved gas saturation often exceeds the standard in the Little Falls Pool, whereas dissolved oxygen levels fall below 4 mg/L in the summer.
Water Quantity Altered Flow Timimg -- Agricultural Practices; Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Runoff Coefficient Alteration Adults Land uses, water diversions, and dams have altered the spring freshet such that the current annual peak flow event occurs rapidly rather than the natural condition of gradual run-off, which consequently creates low, late summer base flows that limit habitat area and complexity.
LARGEMOUTH BASS
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles Annual drawdowns at Lake Spokane limit the stability of warmwater species by increasing the proportional stock density of predatory fish and reducing cover and shelter for juveniles that leads to increased stress for juvenile fish.
MOUNTAIN WHITEFISH
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Juveniles, adults The development of hydropower facilities without fish passage facilities limits genetic exchange, distribution, and habitat connectivity for fish species.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Embedded substrate and reduced habitat complexity, due to anthropogenic activities, limits native salmonid populations.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Riparian zones have been severely impacted by agriculture, grazing, forest management, road construction and other activities.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation All Fine sediment is the most common problem throughout the watershed.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Excessive nutrients exist in the Spokane River below Spokane Falls providing conditions for aquatic vegetation to thrive in low velocity habitats. Accumulation of decaying aquatic vegetation creates biological oxygen demands exacerbating already low oxygen concentrations. dissolved oxygen levels fall below 4 mg/L in the summer.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management; Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Water: Storage or Withdrawal; Water: Temperature and Gas Alteration All In the Spokane River above Spokane Falls, increased water temperature and low dissolved oxygen concentrations are on the 303(d) list. High levels of total dissolved gas is a major problem below Long Lake Dam. Due to the continual series of reservoirs, dissolved gas cannot reach equilibrium. Approximately half of the Little Spokane drainage has impaired water quality throughout the year. Water quality in Hangman Creek is generally poor and state standards for fecal coliform, temperature, pH, and dissolved oxygen are often not met. In Upper Hangman Creek, low dissolved oxygen, high levels of total suspened solids, and high temperatures impair stream conditions and salmonid distribution. During the spring, total dissolved gas saturation often exceeds the standard in the Little Falls Pool, whereas dissolved oxygen levels fall below 4 mg/L in the summer.
Water Quantity Altered Flow Timimg -- Agricultural Practices; Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Runoff Coefficient Alteration Adults Land uses, water diversions, and dams have altered the spring freshet such that the current annual peak flow event occurs rapidly rather than the natural condition of gradual run-off, which consequently creates low, late summer base flows that limit habitat area and complexity.
REDBAND TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Fishery Management Species Introduction Adults Non-native rainbow trout releases lead to hybridization with native redband trout.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Juveniles, adults The development of hydropower facilities without fish passage facilities limits genetic exchange, distribution, and habitat connectivity for fish species.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Embedded substrate and reduced habitat complexity, due to anthropogenic activities, limits native salmonid populations.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Riparian zones have been severely impacted by agriculture, grazing, forest management, road construction and other activities.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles, adults Predation by non-native fishes has depleted native fishes in the Spokane arm of Lake Roosevelt.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation All Fine sediment is the most common problem throughout the watershed.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Heavy Metal; Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals All Excessive nutrients exist in the Spokane River below Spokane Falls providing conditions for aquatic vegetation to thrive in low velocity habitats. Accumulation of decaying aquatic vegetation creates biological oxygen demands exacerbating already low oxygen concentrations. dissolved oxygen levels fall below 4 mg/L in the summer.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management; Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Water: Storage or Withdrawal; Water: Temperature and Gas Alteration All In the Spokane River above Spokane Falls, increased water temperature and low dissolved oxygen concentrations are on the 303(d) list. High levels of total dissolved gas is a major problem below Long Lake Dam. Due to the continual series of reservoirs, dissolved gas cannot reach equilibrium. Approximately half of the Little Spokane drainage has impaired water quality throughout the year. Water quality in Hangman Creek is generally poor and state standards for fecal coliform, temperature, pH, and dissolved oxygen are often not met. In Upper Hangman Creek, low dissolved oxygen, high levels of total suspened solids, and high temperatures impair stream conditions and salmonid distribution. During the spring, total dissolved gas saturation often exceeds the standard in the Little Falls Pool, whereas dissolved oxygen levels fall below 4 mg/L in the summer.
Water Quantity Altered Flow Timimg -- Agricultural Practices; Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Runoff Coefficient Alteration Adults Land uses, water diversions, and dams have altered the spring freshet such that the current annual peak flow event occurs rapidly rather than the natural condition of gradual run-off, which consequently creates low, late summer base flows that limit habitat area and complexity.