Province Summary


Snake Hells Canyon Subbasin Summary

The Snake Hells Canyon subbasin includes the mainstem of the Snake River and the small tributaries that flow into it as the Snake River flows from Hells Canyon Dam to the mouth of the Clearwater River at Lewiston, a length of 109 miles (river mile [RM] 247 to RM 138; Figure 1). The Snake River forms the border between Oregon and Idaho for the upper 71 miles of the subbasin and the border between Washington and Idaho for the lower 38 miles. The subbasin contains 862 square miles, or 551,792 acres. About 62% of this area falls in Idaho, 31% is in Oregon and the remaining 7% is in Washington. The subbasin contains part of five counties: Adams, Idaho, and Nez Perce in Idaho; Asotin in Washington; and Wallowa in Oregon. The lower portion of the subbasin contains the town of Asotin and portions of Clarkston and Lewiston. The remainder of the subbasin is either rural or undeveloped. The Salmon, Imnaha, Grande Ronde, and Clearwater rivers, as well as Asotin Creek, are major tributaries that join the Snake River in the Snake Hells Canyon subbasin. These rivers drain a combined area of 19,280 square miles (12,339,200 acres) and dramatically influence the water quality and hydrologic conditions in the Snake River.

Source: Snake Hells Canyon Subbasin Plan

Status and Trends of Focal Species in Snake Hells Canyon Subbasin
 
Species ESU MPG Population Biological Objective (s) Biological Status Federal Status Data / Charts
Fall Chinook Snake River      Subbasin Plan Objective :
3% smolt to adult return (SAR) rate to Lower Granite Dam292
 
Redd Counts
2014: 2,808 redds 174
Adult Counts (Lower Granite Dam)
2017: 24,431 adults 60
Threatened Status & Trends
Spring/Summer Chinook Snake River      Subbasin Plan Objective :
4-6% smolt to adult return (SAR) rates to Lower Granite Dam292
 
Adult Counts (Lower Granite Dam)
2017: 36,309 adults 60
Threatened Status & Trends
Pacific Lamprey       Subbasin Plan Objective :
None
 
Adult Counts (Lower Granite Dam)
2017: 472 adults 60
Species of Concern Status & Trends
Sockeye Snake River      Subbasin Plan Objective :
None
 
Adult Counts (Lower Granite Dam)
2017: 288 adults 60
Endangered Status & Trends
Summer Steelhead Snake River      Subbasin Plan Objective :
4% smolt to adult return (SAR) rate to Lower Granite Dam292
 
Adult Counts (Lower Granite Dam)
2017: 71,178 adults 60
Threatened Status & Trends
Bull Trout Sheep Creek, Granite Creek    Sheep Creek, Granite Creek  Draft Recovery Plan Criteria :
No numeric objective (abundance estimates considered a research need)290
 
Unknown Threatened No Data
White Sturgeon       Subbasin Plan Objective :
321
 
Hell Canyon (Snake River only)
Estimated abundance (fish > 60 cm FL) = 3,625 fish 437
Not Listed No Data
Redband Trout     Lower Snake River; Magraw Creek  Subbasin Plan Objective :
None
 
Unknown 426 Species of Concern No Data
    
View abundance data for Snake Hells Canyon Subbasin
 
Hatcheries located in Snake Hells Canyon Subbasin
**Hatchery data will be updated in 2016**

Hatchery / Acclimation Pond Hatchery Info Releases / Returns Program Reviews(APRE / HSRG / HGMP / USFWS) Map
Captain Johns Rapids View View View  
Pittsburg Landing View View View  
 
Hatchery Releases and Returns to Snake Hells Canyon Subbasin363
**Hatchery data will be updated in 2016**

Some releases into subbasins may be from hatcheries located in other provinces and subbasins. Hatchery releases of anadromous fish, within the geographic range of an ESU/DPS, are listed accordingly.
 
Hatchery / Acclimation Pond Species ESU/DPS Released in 2009 Returns to Collection Facility in 2009 Data as of
Captain Johns Rapids Fall Chinook Snake River Fall Chinook ESU 665,694 8 / 30 / 2010
Lyons Ferry Hatchery Fall Chinook Snake River Fall Chinook ESU 438,485 8 / 30 / 2010
Pittsburg Landing Fall Chinook Snake River Fall Chinook ESU 568,266 8 / 30 / 2010
Recovery Status for ESA-Listed Salmon and Steelhead in the Snake Hells Canyon Subbasin

    No recovery status for Snake Hells Canyon subbasin.
Limiting Factors in the Snake Hells Canyon Subbasin 426

BULL TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning and rearing habitats in the Snake River have been inundated.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River.
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices; Forest Management; Urbanization Wetland Loss; Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Road construction has altered the quality, quantity, and connectivity of habitat in tributary watersheds.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Riparian Degradation Juveniles, adults Livestock grazing degrades riparian habitats in tributary watersheds. Introduction of exotic plants has reduced riparian function.
Water Quality Temperature -- Agricultural Practices; Forest Management Riparian Degradation All Temperatures exceed state standards in the entire reach of the Snake River.
FALL CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning and rearing habitats in the Snake River have been inundated.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River.
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 Wetland Loss; Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Road construction has altered the quality, quantity, and connectivity of habitat in tributary watersheds.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Riparian Degradation Juveniles, adults Riparian growth along the Snake River is hindered by lack of sediment and therefore lack of substrate. Livestock grazing degrades riparian habitats in tributary watersheds. Introduction of exotic plants has reduced riparian function.
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 Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles Smallmouth bass prey on juvenile salmonids in the Snake River.
Water Quality Temperature -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Temperatures exceed state standards in the entire reach of the Snake River. Sediment is deficient below Hells Canyon Dam due to trapping of suspended sediment and bedload. Dissolved gas levels below Hells Canyon Dam may impair fish populations
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Hydropower operations at Hells Canyon and Lower Granite dams have altered flow regimes. Fall Chinook are susceptible because changes in flow affect spawning timing, spawning location, egg incubation, and out-migration of juveniles.
PACIFIC LAMPREY
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning and rearing habitats in the Snake River have been inundated.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River.
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.
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices; Forest Management; Urbanization Wetland Loss; Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Road construction has altered the quality, quantity, and connectivity of habitat in tributary watersheds.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Riparian Degradation Juveniles, adults Livestock grazing degrades riparian habitats in tributary watersheds. Introduction of exotic plants has reduced riparian function.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Juveniles and adults must pass eight mainstem dams during
Water Quality Temperature -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Temperatures exceed state standards in the entire reach of the Snake River. Sediment is deficient below Hells Canyon Dam due to trapping of suspended sediment and bedload. Dissolved gas levels below Hells Canyon Dam may impair fish populations
REDBAND TROUT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning and rearing habitats in the Snake River have been inundated.
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices; Forest Management; Urbanization Wetland Loss; Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Road construction has altered the quality, quantity, and connectivity of habitat in tributary watersheds.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Riparian Degradation Juveniles, adults Livestock grazing degrades riparian habitats in tributary watersheds. Introduction of exotic plants has reduced riparian function.
Water Quality Temperature -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Temperatures exceed state standards in the entire reach of the Snake River.
SOCKEYE
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 Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River.
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 Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles Smallmouth bass prey on juvenile salmonids in the Snake River.
Water Quality Temperature -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Temperatures exceed state standards in the entire reach of the Snake River. Sediment is deficient below Hells Canyon Dam due to trapping of suspended sediment and bedload. Dissolved gas levels below Hells Canyon Dam may impair fish populations
SPRING/SUMMER CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning and rearing habitats in the Snake River have been inundated.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River.
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 Wetland Loss; Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Road construction has altered the quality, quantity, and connectivity of habitat in tributary watersheds.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Riparian Degradation Juveniles, adults Riparian growth along the Snake River is hindered by lack of sediment and therefore lack of substrate. Livestock grazing degrades riparian habitats in tributary watersheds. Introduction of exotic plants has reduced riparian function.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Spring/Summer Chinook are primarily subject to freshwater harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles Smallmouth bass prey on juvenile salmonids in the Snake River.
Water Quality Temperature -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Temperatures exceed state standards in the entire reach of the Snake River. Sediment is deficient below Hells Canyon Dam due to trapping of suspended sediment and bedload. Dissolved gas levels below Hells Canyon Dam may impair fish populations
SUMMER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning and rearing habitats in the Snake River have been inundated.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River.
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 Wetland Loss; Impervious Surfaces (Road Density); Riparian Degradation Juveniles, adults Road construction has altered the quality, quantity, and connectivity of habitat in tributary watersheds.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Riparian Degradation Juveniles, adults Riparian growth along the Snake River is hindered by lack of sediment and therefore lack of substrate. Livestock grazing degrades riparian habitats in tributary watersheds. Introduction of exotic plants has reduced riparian function.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass eight mainstem dams during migration.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles Smallmouth bass prey on juvenile salmonids in the Snake River.
Water Quality Temperature -- Dam or Hydropower Facility Management Water: Temperature and Gas Alteration All Temperatures exceed state standards in the entire reach of the Snake River. Sediment is deficient below Hells Canyon Dam due to trapping of suspended sediment and bedload. Dissolved gas levels below Hells Canyon Dam may impair fish populations
WHITE STURGEON
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Juveniles, adults Spawning habitats in the Snake River have been inundated.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults Hells Canyon Dam completely blocks fish passage out of the subbasin to the Upper Snake River. White sturgeon have been effectively isolated.