Limiting Factors



Columbia Plateau Province

Deschutes Subbasin 376, 387, 388

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; Forest Management; Urbanization; Migration Impediments Juveniles, adults The lack of fish passage at the Pelton Round Butte complex has fragmemted bull trout populations. Passage barriers are present on Link and Spring creeks in the Metolius River watershed.
Instantaneous Mortality Predation by or Competition with Non-Native Species -- Species Management; Fishery Management Species Introduction Juveniles, adults Brook trout are a major threat to bull trout in the Warm Springs River due to competition for limited rearing habitat. Brook and brown trout may be limiting for some bull trout populations in the Metolius River watershed due to their potential for interaction.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Forest Management; Urbanization Sediment: Bank Destabilization; Impervious Surfaces (Road Density) All Sedimentation from forest practices, catastrophic fire and extensive road system impacts stream substrate quality.
FALL CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Artificial Propogation Straying Adult spawners Large numbers of out-of-basin stray fall Chinook spawning with indigenous populations pose serious genetic risks.
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 Morphological Changes Freshwater-Floodplain Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles Floodplains are generally degraded throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Juveniles Riparian corridors are generally degraded throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management Wood/Structure Removal Juveniles Large wood is generally lacking throughout the subbasin.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Fall Chinook are subject to both ocean and freshwater harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass two mainstem dams during migration. The lack of fish passage at the Pelton Round Butte complex has extirpated upstream anadromous populations.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration Juveniles Water temperature and dissolved oxygen levels do not meet state criteria immediately downstream from the Pelton Round Butte complex.
Water Quantity Decreased Water Quantity -- Agricultural Practices Water: Storage or Withdrawal, Channelization, Management Juveniles Seasonal low flows limit adult migration and juvenile rearing.
PACIFIC LAMPREY
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 Juveniles 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 two mainstem dams during migration. The lack of fish passage at the Pelton Round Butte complex has extirpated upstream anadromous populations.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration Juveniles Water temperature and dissolved oxygen levels do not meet state criteria immediately downstream from the Pelton Round Butte complex.
Water Quantity Decreased Water Quantity -- Agricultural Practices Water: Storage or Withdrawal, Channelization, Management Juveniles Seasonal low flows limit adult migration and juvenile rearing.
REDBAND 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 Migration Impediments Juveniles, adults The lack of fish passage at the Pelton Round Butte complex has fragmemted redband trout populations.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation All Degraded riparian vegetation reduces bank stability in small tributaries of the lower Deschutes River. Riparian corridors are generally degraded throughout the subbasin.
Water Quality Temperature; Oxygen -- Agriculture Practices; Dam or Hydropower Facility Management Water: Temperature and Gas Alteration; Riparian Degradation All Water temperatures in Buck Hollow, Willow, Bakeoven, Salt, Robin and Lake creeks exceed state water quality criteria for salmonid production. Water temperature and dissolved oxygen levels do not meet state criteria immediately downstream from the Pelton Round Butte complex.
Water Quantity Decreased Water Quantity -- Agricultural Practices Water: Storage or Withdrawal, Channelization, Management Juveniles, adults Trout movement is generally blocked by intermittent flow or subsurface flow. Low winter flows from Wickiup Dam to Bend limit fish productivity because large woody debris and spawning gravel along the stream margin become unavailable. Fish also become stranded in pools and side channels. Summer flow is very low from Bend to Big Falls because of irrigation diversions. Low summer flows also restrict fish populations in tributaries such as Trout Creek. Seasonal low flows limit adult migration and juvenile rearing in Whychus Creek.
SOCKEYE
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass two mainstem dams during migration. The lack of fish passage at the Pelton Round Butte complex has extirpated upstream anadromous populations.
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 Morphological Changes Freshwater-Floodplain Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles Floodplains are generally degraded throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Juveniles Riparian corridors are generally degraded throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management Wood/Structure Removal Juveniles Large wood is generally lacking throughout the subbasin.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass two mainstem dams during migration. The lack of fish passage at the Pelton Round Butte complex has extirpated upstream anadromous populations.
Water Quality Temperature; Oxygen -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration Juveniles Water temperature and dissolved oxygen levels do not meet state criteria immediately downstream from the Pelton Round Butte complex.
Water Quantity Decreased Water Quantity -- Agricultural Practices Water: Storage or Withdrawal, Channelization, Management Juveniles Seasonal low flows limit adult migration and juvenile rearing.
SUMMER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Artificial Propogation Straying Adult spawners Large numbers of out-of-basin stray Summer Steelhead spawning with indigenous populations pose serious genetic risks.
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 Morphological Changes Freshwater-Floodplain Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Riparian Degradation Juveniles Floodplains are generally degraded throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Juveniles Riparian corridors are generally degraded throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management Wood/Structure Removal Juveniles Large wood is generally lacking throughout the subbasin.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass two mainstem dams during migration. The lack of fish passage at the Pelton Round Butte complex has extirpated upstream anadromous populations.
Water Quality Temperature; Oxygen -- Agriculture Practices; Dam or Hydropower Facility Management Water: Temperature and Gas Alteration; Riparian Degradation Eggs, juveniles High summer water temperatures in tributaries utilized by summer steelhead result from low flow and grazing pressure. Water temperatures in Buck Hollow, Willow, Bakeoven, Salt, Robin and Lake creeks exceed state water quality criteria for salmonid production. Water temperature and dissolved oxygen levels do not meet state criteria immediately downstream from the Pelton Round Butte complex.
Water Quantity Decreased Water Quantity -- Agricultural Practices Water: Storage or Withdrawal, Channelization, Management Eggs, juveniles Low summer flows restrict fish populations in tributaries such as Trout Creek. Seasonal low flows limit adult migration and juvenile rearing.