Limiting Factors



Columbia Cascade Province

Columbia Upper Middle Subbasin

RAINBOW TROUT
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 Agricultural Practices Riparian Degradation; Bank Destabilization Juveniles Steep, sparsely vegetated shorelines limit rearing habitat.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management Predators: Fish; Predators: Avian Juveniles Introductions of non-native predator fishes as well as an increase in populations of indigenous predator fish species, and the immigration of diving birds are potentially limiting survival of juvenile salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Dam or Hydropower Facility Management Sediment: Retention Adult spawners Smoothing of the hydrograph and lack of significant reservoir fluctuations has resulted in an increased amount of fine sediment in the lower portions of the reservoirs thus concentrating anadromous salmonid spawning to the upper reaches of the reservoirs.
Water Quality Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration; Pollution and Contamination Juveniles Occasionally total dissolved gas levels exceed maximum allowed levels during periods of high run-off. Mean annual phosphate concentrations often exceed levels that could stimulate algal blooms.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Hydrologic Cycle Alteration Juveniles Operation of Wanapum, Rock Island, Rocky Reach, Wells, and Chief Joseph dams results in rapid flushing rates and no thermal stratification during the summer. Productivity is limited due to rapid flushing rates, cold temperatures, and lack of shallow water areas. Food that is available in the reservoirs typically provides lower amounts of energy than found in free-flowing areas such as the Hanford Reach.
SPRING CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices Riparian Degradation; Bank Destabilization Juveniles Steep, sparsely vegetated shorelines limit rearing habitat.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management Predators: Fish; Predators: Avian Juveniles Introductions of non-native predator fishes as well as an increase in populations of indigenous predator fish species, and the immigration of diving birds are potentially limiting survival of juvenile salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Dam or Hydropower Facility Management Sediment: Retention Adult spawners Smoothing of the hydrograph and lack of significant reservoir fluctuations has resulted in an increased amount of fine sediment in the lower portions of the reservoirs thus concentrating anadromous salmonid spawning to the upper reaches of the reservoirs.
Water Quality Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration; Pollution and Contamination Juveniles Occasionally total dissolved gas levels exceed maximum allowed levels during periods of high run-off. Mean annual phosphate concentrations often exceed levels that could stimulate algal blooms.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Hydrologic Cycle Alteration Juveniles Operation of Wanapum, Rock Island, Rocky Reach, Wells, and Chief Joseph dams results in rapid flushing rates and no thermal stratification during the summer. Productivity is limited due to rapid flushing rates, cold temperatures, and lack of shallow water areas. Food that is available in the reservoirs typically provides lower amounts of energy than found in free-flowing areas such as the Hanford Reach.
SUMMER CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management Predators: Fish; Predators: Avian Juveniles Introductions of non-native predator fishes as well as an increase in populations of indigenous predator fish species, and the immigration of diving birds are potentially limiting survival of juvenile salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Dam or Hydropower Facility Management Sediment: Retention Adult spawners Smoothing of the hydrograph and lack of significant reservoir fluctuations has resulted in an increased amount of fine sediment in the lower portions of the reservoirs thus concentrating anadromous salmonid spawning to the upper reaches of the reservoirs.
Water Quality Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration; Pollution and Contamination Juveniles Occasionally total dissolved gas levels exceed maximum allowed levels during periods of high run-off. Mean annual phosphate concentrations often exceed levels that could stimulate algal blooms.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Hydrologic Cycle Alteration Juveniles Operation of Wanapum, Rock Island, Rocky Reach, Wells, and Chief Joseph dams results in rapid flushing rates and no thermal stratification during the summer. Productivity is limited due to rapid flushing rates, cold temperatures, and lack of shallow water areas. Food that is available in the reservoirs typically provides lower amounts of energy than found in free-flowing areas such as the Hanford Reach.
SUMMER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management Predators: Fish; Predators: Avian Juveniles Introductions of non-native predator fishes as well as an increase in populations of indigenous predator fish species, and the immigration of diving birds are potentially limiting survival of juvenile salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Dam or Hydropower Facility Management Sediment: Retention Adult spawners Smoothing of the hydrograph and lack of significant reservoir fluctuations has resulted in an increased amount of fine sediment in the lower portions of the reservoirs thus concentrating anadromous salmonid spawning to the upper reaches of the reservoirs.
Water Quality Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration; Pollution and Contamination Juveniles Occasionally total dissolved gas levels exceed maximum allowed levels during periods of high run-off. Mean annual phosphate concentrations often exceed levels that could stimulate algal blooms.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal; Water: Hydrologic Cycle Alteration Juveniles Operation of Wanapum, Rock Island, Rocky Reach, Wells, and Chief Joseph dams results in rapid flushing rates and no thermal stratification during the summer. Productivity is limited due to rapid flushing rates, cold temperatures, and lack of shallow water areas. Food that is available in the reservoirs typically provides lower amounts of energy than found in free-flowing areas such as the Hanford Reach.