Province Summary


Lewis Subbasin Summary

The Lower North Fork Lewis Basin extends from the mouth to Merwin Dam, excluding the East Fork Lewis drainage. Below Merwin Dam, the Lewis River flows generally west/southwest, forming the border of Cowlitz and Clark Counties. The Lewis enters the Columbia at RM 87, a few miles southwest of Woodland, Washington. The Lower Lewis drainage encompasses approximately 65,464 acres (102 mi2).

The lower 12 miles of the mainstem flow through a broad alluvial valley characterized by agriculture and residential uses. This section is extensively channelized. Tidal influence extends to approximately RM 11. The valley narrows above RM 12 and forms a canyon between the confluence of Cedar Creek (RM 15.7) and Merwin Dam (RM 19.5). The 240-foot high Merwin Dam, completed in 1931, presents a passage barrier to all anadromous fish, blocking up to 80% of the historically available habitat. Major tributaries to the Lower Lewis include the EF Lewis, Johnson Creek, and Cedar Creek. Cedar Creek provides some of the most productive anadromous fish habitat in the North Fork basin.

The bulk of the land is forested and a large percentage is managed as commercial forest. Agriculture and residential activities are found in valley bottom areas. Recreation uses and residential development have increased in recent years. The population of the basin is small. The year 2000 population was approximately 14,300 persons. Small rural communities include Chelatchie and Amboy (Cedar Creek drainage). The largest population center is Woodland, which is situated on the lower mainstem. The majority of the basin is forested, except for valley bottom areas, which are dominated by residential and agricultural uses.

Source: Lower Columbia Province Plan

Status and Trends of Focal Species in Lewis Subbasin
 
Species ESU MPG Population Biological Objective (s) Biological Status Federal Status Data / Charts
Fall Chinook Lower Columbia  Cascade Fall  Lewis  Draft Recovery Plan Criteria :
1,500 natural adults298
 
NOSA Estimate
2015: 4,360 spawners 474
Threatened Status & Trends
Late Fall Chinook Lower Columbia  Cascade Late Fall  Lewis  Draft Recovery Plan Criteria :
7,300 natural adults298
 
NOSA Estimate
2015: 23,614 spawners 474
Threatened Status & Trends
Spring Chinook Lower Columbia  Cascade Spring  Lewis  Draft Recovery Plan Criteria :
1,500 natural adults298
 
Adult Escapement (natural)
2014: 428 adults 508
Threatened Status & Trends
Chum Columbia River  Cascade  Lewis  Draft Recovery Plan Criteria :
1,300 natural adults298
 
Unknown Threatened No Data
Coho Lower Columbia  Cascade  North Fork, East Fork  Draft Recovery Plan Criteria :
North Fork - 500 natural adults; East Fork - 2,000 natural adults298
 
NOSA Estimate
2012: North Fork Lewis River - 2,579 spawners474
2015: Lewis River- 4,360 spawners474
East Fork Lewis River (early and late) - 389 spawners474
Threatened Status & Trends
Coastal Cutthroat       Subbasin Plan Objective :
None300
 
Unknown Species of Concern Status & Trends
Summer Steelhead Lower Columbia  Cascade Summer  North Fork, East Fork  Draft Recovery Plan Criteria :
North Fork - No Objective; East Fork - 500 natural adults298
 
Adult Escapement (natural)
2015: East Fork - 843 adults (natural)122
Threatened Status & Trends
Winter Steelhead Lower Columbia  Cascade Winter  North Fork, East Fork  Draft Recovery Plan Criteria :
North Fork - 400 natural adults; East Fork - 500 natural adults298
 
Adult Escapement (natural)
2015: 678 adults (natural)121
Threatened Status & Trends
Bull Trout Lewis (Within the Lower Columbia River Recovery Unit)    Cougar Creek, Pine Creek, Rush Creek  Draft Recovery Plan Criteria :
Maintain current distribution, restore distribution to previously occupied areas, and maintain stable or increasing trends in abundance310
 
Population Estimate
2015: 697 fish (Swift Reservoir)479
Threatened Status & Trends
    
View abundance data for Lewis Subbasin
 
Hatcheries located in Lewis Subbasin
**Hatchery data will be updated in 2016**

Hatchery / Acclimation Pond Hatchery Info Releases / Returns Program Reviews(APRE / HSRG / HGMP / USFWS) Map
Echo Net Pen View View    
First Fish View View View  
Lewis River Hatchery View View View View
Merwin Hatchery View View View View
Speelyai Hatchery View View View View
Speelyai Net Pen (Merwin Reservoir) View   View  
 
Hatchery Releases and Returns to Lewis Subbasin358, 363, 359, 360
**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
Carlisle Lake Project Coho Lower Columbia River Coho ESU 10,000 8 / 30 / 2010
Winter Steelhead Lower Columbia River Steelhead DPS 32,000 8 / 30 / 2010
Echo Net Pen Spring Chinook Lower Columbia River Chinook ESU 152,000 8 / 30 / 2010
First Fish Coho Lower Columbia River Coho ESU 810,000 8 / 30 / 2010
Spring Chinook Lower Columbia River Chinook ESU 150,000 8 / 30 / 2010
Summer Steelhead Lower Columbia River Steelhead DPS 70,000 8 / 30 / 2010
Goldendale Trout Hatchery Brook Trout 7,726 8 / 30 / 2010
Brown Trout 1,952 8 / 30 / 2010
Rainbow Trout 34,949 8 / 30 / 2010
Tiger Trout 2,601 8 / 30 / 2010
Westslope Cutthroat 4,163 8 / 30 / 2010
Klineline Ponds Winter Steelhead Lower Columbia River Steelhead DPS 19,836 8 / 30 / 2010
Lewis River Hatchery Coho Lower Columbia River Coho ESU 1,723,668 21,638 8 / 30 / 2010
Spring Chinook Lower Columbia River Chinook ESU 953,676 1 8 / 30 / 2010
Summer Steelhead Lower Columbia River Steelhead DPS 302 8 / 30 / 2010
Winter Steelhead Lower Columbia River Steelhead DPS 611 8 / 30 / 2010
Merwin Hatchery Coho Lower Columbia River Coho ESU 22,806 8 / 30 / 2010
Rainbow Trout 3,733 8 / 30 / 2010
Spring Chinook Lower Columbia River Steelhead DPS 1,354 8 / 30 / 2010
Summer Steelhead Lower Columbia River Steelhead DPS 175,263 7,809 8 / 30 / 2010
Winter Steelhead Lower Columbia River Steelhead DPS 93,491 1,476 (at Dam) 8 / 30 / 2010
Meseberg Hatchery Tiger Muskie 2,220 8 / 30 / 2010
Mossyrock Trout Hatchery Brown Trout 24,045 8 / 30 / 2010
Rainbow Trout 15,933 8 / 30 / 2010
Westslope Cutthroat 1,075 8 / 30 / 2010
Skamania Hatchery Coastal Cutthroat 1,676 8 / 30 / 2010
Summer Steelhead Lower Columbia River Steelhead DPS 15,000 8 / 30 / 2010
Winter Steelhead Lower Columbia River Steelhead DPS 60,844 8 / 30 / 2010
Speelyai Hatchery Kokanee 210,618 8 / 30 / 2010
Rainbow Trout 55,161 8 / 30 / 2010
Syversion Project Coho 4,760 8 / 30 / 2010
Trout Lodge Commercial Rainbow Trout 1,184 8 / 30 / 2010
Vancouver Hatchery Rainbow Trout 3,000 8 / 30 / 2010
Venersberg Fire Coho Lower Columbia River Coho ESU 90,000 8 / 30 / 2010
Recovery Status for ESA-Listed Salmon and Steelhead in the Lewis Subbasin369

Updated : 5/27/2010

Species Population Abundance Threshold Mean Abundance Major Spawning Area Growth Rate Recruits / Spawners Current Viability
Summer Steelhead North Fork Lewis River 560 150 -- -- -- Very Low
  East Fork Lewis River -- <50 -- -- -- Very Low
Fall Chinook Lewis River 740 <50 -- -- -- Very Low
  North Lewis River Late 2,430 7,300 -- -- -- Very High
Spring Chinook North Fork Lewis River -- 300 -- -- -- Very Low
Coho North Fork Lewis River 2,890 200 -- -- -- Very Low
  East Fork Lewis River -- <50 -- -- -- Very Low
Chum Lewis River -- <100 -- -- -- Very Low
Limiting Factors in the Lewis Subbasin 362, 371

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 Merwin Dam (river mile 20) blocks anadromous fish passage to the Upper North Fork watershed. Culvert-related passage problems exist on Johnson, Cedar, Beaver, John, Brush and Unnamed creeks (Upper North Fork watershed).
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Juveniles, adults Riparian areas are degraded throughout Cedar Creek. Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Juveniles, adults Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization All Impacts due to sediment occur throughout the subbasin. In Cedar Creek, excessive sedimentation is caused by cattle grazing and residential impacts.
CHUM
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; Urbanization Riparian Degradation; Wood/Structure Removal Adults Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Adults Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization Eggs, adults Impacts due to sediment occur throughout the subbasin.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Hydrologic Cycle Alteration All Altered flows from hydro operations impact egg survival.
COASTAL CUTTHROAT
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 Merwin Dam (river mile 20) blocks anadromous fish passage to the Upper North Fork watershed. Culvert-related passage problems exist on Johnson, Cedar, Beaver, John, Brush and Unnamed creeks (Upper North Fork watershed).
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Juveniles, adults Diking and land use practices have decreased floodplain connectivity and function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Juveniles, adults Riparian areas are degraded throughout Cedar Creek. Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Juveniles, adults Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization All Impacts due to sediment occur throughout the subbasin. In Cedar Creek, excessive sedimentation is caused by cattle grazing and residential impacts.
Water Quantity Decreased Water Quantity; Increased Water Quantity -- Forest Management Impervious Surfaces (Road Density); Water: Runoff Coefficient Alteration Juveniles, adults Flow alterations are related to forest condition and roads in the upper reaches of the East Fork watershed.
COHO
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Food Competition -- Artificial Propogation Intraspecific Interaction Fry, summer parr Hatchery releases lead to competition with naturally produced juveniles.
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; Urbanization Diking; Filling; Riparian Degradation; Juveniles Diking and land use practices have decreased floodplain connectivity and function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Fry, summer parr Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Fry, summer parr Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Coho are subject to both ocean and freshwater harvest.
Instantaneous Mortality Pathogens -- Artificial Propogation Disease Amplification and Transfer Fry, summer parr Pathogens from hatcheries may limit productivity.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Fry Non-native species introductions have lead to community shifts and predation issues.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization Summer parr Impacts due to sediment occur throughout the subbasin.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Hydrologic Cycle Alteration All Altered flows from hydro operations impact egg survival.
FALL CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Food Competition -- Artificial Propogation Intraspecific Interaction Fry Hatchery releases lead to competition with naturally produced juveniles.
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; Urbanization Diking; Filling; Riparian Degradation; Fry, adults Diking and land use practices have decreased floodplain connectivity and function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Fry, adults Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Fry, adults Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Fall Chinook are subject to both ocean and freshwater harvest.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Fry Non-native species introductions have lead to community shifts and predation issues.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization Eggs, fry, adults Impacts due to sediment occur throughout the subbasin.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Hydrologic Cycle Alteration All Altered flows from hydro operations impact egg survival.
SPRING CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Food Competition -- Artificial Propogation Intraspecific Interaction Summer parr Hatchery releases lead to competition with naturally produced juveniles.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Forest Management; Urbanization Migration Impediments Adults Merwin Dam (river mile 20) blocks anadromous fish passage to the Upper North Fork watershed. Culvert-related passage problems exist on Johnson, Cedar, Beaver, John, Brush and Unnamed creeks (Upper North Fork watershed).
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; Urbanization Diking; Filling; Riparian Degradation; Fry, adults Diking and land use practices have decreased floodplain connectivity and function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Fry, summer parr Riparian areas are degraded throughout Cedar Creek. Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Fry, summer parr Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Fry, summer parr Non-native species introductions have lead to community shifts and predation issues.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization Eggs, fry, summer parr Impacts due to sediment occur throughout the subbasin. In Cedar Creek, excessive sedimentation is caused by cattle grazing and residential impacts.
Water Quantity Decreased Water Quantity; Increased Water Quantity; Altered Flow Timing -- Forest Management; Dam or Hydropower Facility Management Impervious Surfaces (Road Density); Water: Runoff Coefficient Alteration; Water: Hydrologic Cycle Alteration Juveniles, adults Flow alterations are related to forest condition and roads in the upper reaches of the East Fork watershed. Hydropower actions alter flow regimes and impair spawning and rearing in the Lower North Fork watershed.
SUMMER STEELHEAD
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 Adults Merwin Dam (river mile 20) blocks anadromous fish passage to the Upper North Fork watershed. Culvert-related passage problems exist on Johnson, Cedar, Beaver, John, Brush and Unnamed creeks (Upper North Fork watershed).
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; Urbanization Diking; Filling; Riparian Degradation; Juveniles Diking and land use practices have decreased floodplain connectivity and function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Juveniles Riparian areas are degraded throughout Cedar Creek. Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Juveniles Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization Eggs Impacts due to sediment occur throughout the subbasin. In Cedar Creek, excessive sedimentation is caused by cattle grazing and residential impacts.
Water Quantity Decreased Water Quantity; Increased Water Quantity; Altered Flow Timing -- Forest Management; Dam or Hydropower Facility Management Impervious Surfaces (Road Density); Water: Runoff Coefficient Alteration; Water: Hydrologic Cycle Alteration Juveniles, adults Flow alterations are related to forest condition and roads in the upper reaches of the East Fork watershed. Hydropower actions alter flow regimes and impair spawning and rearing in the Lower North Fork watershed.
WINTER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage(s) Description
Food Competition -- Artificial Propogation Intraspecific Interaction Fry, summer parr Hatchery releases lead to competition with naturally produced juveniles.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management; Forest Management; Urbanization Migration Impediments Adults Merwin Dam (river mile 20) blocks anadromous fish passage to the Upper North Fork watershed. Culvert-related passage problems exist on Johnson, Cedar, Beaver, John, Brush and Unnamed creeks (Upper North Fork watershed).
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; Urbanization Diking; Filling; Riparian Degradation; Juveniles Diking and land use practices have decreased floodplain connectivity and function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices; Urbanization Diking; Riparian Degradation Juveniles Riparian areas are degraded throughout Cedar Creek. Channelization (diking) and degraded riparian areas are present throughout the mainstem and the East Fork. Invasive plants contribute to habitat degradation along the mainstem.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Riparian Degradation; Wood/Structure Removal Juveniles Low levels of large woody debris contribute to the lack of habitat diversity throughout the subbasin.
Instantaneous Mortality Pathogens -- Artificial Propogation Disease Amplification and Transfer Fry, summer parr Pathogens from hatcheries may limit productivity.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Fry Non-native species introductions have lead to community shifts and predation issues.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Riparian Degradation; Sediment: Bank Destabilization Eggs Impacts due to sediment occur throughout the subbasin. In Cedar Creek, excessive sedimentation is caused by cattle grazing and residential impacts.
Water Quantity Decreased Water Quantity; Increased Water Quantity; Altered Flow Timing -- Forest Management; Dam or Hydropower Facility Management Impervious Surfaces (Road Density); Water: Runoff Coefficient Alteration; Water: Hydrologic Cycle Alteration Juveniles, adults Flow alterations are related to forest condition and roads in the upper reaches of the East Fork watershed. Hydropower actions alter flow regimes and impair spawning and rearing in the Lower North Fork watershed.