Draft Imnaha Subbasin Summary November 30, 2001 Prepared for the Northwest Power Planning Council Subbasin Team Leader


Appendix E - Habitat matrix table for the Imnaha River Section 7 watershed (reproduced from USDA Forest Service 1998a)



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Appendix E - Habitat matrix table for the Imnaha River Section 7 watershed (reproduced from USDA Forest Service 1998a)




Pathway/Indicators

Properly Functioning

At Risk

Not Properly Functioning

Water Quality

Temperature (1)

50-57F (max 7-day average)

57-60F (max 7-day-spawning)

57-64F (migration/rearing)



>60F (max 7-day spawning)

>64F (migration/rearing)



Sediment/Substrate (1)

Embeddedness <20%. Dominant substrate is gravel or cobble. Gravel/cobble bars stable. Turbidity low.

Embeddedness 20-30%. Gravel and cobble is subdominant. Gravel/cobble bars are in the process of stabilizing. Turbidity moderate.

Embeddedness >30%. Bedrock, sand, silt, or small gravel dominant. Gravel/cobble bars very mobile. Turbidity high.

Chemical Contamination

Low levels of chemical contamination; no CWA 303(d) designated reaches.


Moderate levels of chemical contamination; one CWA 303(d) designated reach.

High levels of chemical contamination; more than one CWA 303(d) designated reach.

Habitat Access

Physical Barriers

Man-made barriers do not restrict fish passage.

Man-made barriers present restrict fish passage at base/low flows.

Man-made barriers present restrict fish passage at a range of flow conditions.

Habitat Elements

Large Woody Material (1)

>20 pieces/mi.



Meets standards (left). Adequate sources for LWM recruitment from riparian areas.

Currently meets standards for properly functioning, but lacks potential sources from riparian areas of LWM recruitment to maintain that standard, or

Doesn’t meet standard, but has recruitment potential.



Does not meet standards for properly functioning and lacks potential LWM recruitment.

Pool Frequency and Quality (1)

Width (ft.) Pools/mi.
  1. 184


  1. 96

15 70

  1. 56

  1. 47

50 26

Meets pool frequency standards (left) and LWM recruitment standards for properly functioning habitat, or has adequate flow and bedrock to maintain pools. Residual (holding) pool depth greater than 3 meters with good cover and cool water. Minor reduction of pool volume by fine sediment acceptable.

Meets pool frequency standards (left) but LWM recruitment standards inadequate to maintain pools over time. Lacks adequate flow or bedrock to form stable pools. Residual (holding) pool depth less than 3 meters with less than adequate cover/temperature. Moderate reduction in pool volume by fine sediment.

Does not meet pool frequency standards. Does not contain deep pools. Pool volumes are reduced by fine sediment.

Off-Channel habitat

Natural potential or backwaters with cover and low energy off-channel areas

Some backwater and high-energy side channels.

Few or no backwaters; no off-channel ponds.

Refugia

Habitat refugia exists and are buffered

Habitat refugia exists but are not adequately buffered

Habitat refugia does not exist.

Channel Conditions and Dynamics

Width:Depth ratio (1)


Meet Rosgen’s classification system (Rosgen 1996).

Does not meet Rosgen’s classification system, but morphology/vegetation components are in place and system is moving towards meeting this classification.

Does not meet Rosgen’s classification system and morphology/vegetation componenets are not in place.

Streambank Condition (1)

>90% stable.

80-90% stable.

<80% stable.

Floodplain Connectivity

Off-channel areas are hydrologically connected to the main channel. Overbank flows occur and maintain wetland functions, riparian vegetation and succession, where channel type allows.

Reduced linkage of wetland floodplains. Overbank flows are reduced relative to historic frequency as evidenced by moderate degradation of wetland function, where channel type allows formation of wetlands.

Severe reduction in hydrologic connectivity. Wetland functions degraded, where channel type allows formation of wetlands.

(Continued on next page)



Pathway/Indicators

Properly Functioning

At Risk

Not Properly Functioning

Hydrology/flow


Changes in Peak/Base Flow

Watershed hydrographs indicated peak flow, base flow, and flow timing characteristics comparable to an undisturbed watershed.

Some evidence of altered peak flow, base flow, and/or flow timing.

Pronounced changes in peak flow, base flow, and/or flow timing.

Increase in Drainage Network

Zero or minimum increase in drainage network density due to roads.

Moderate increases in drainage network density due to roads (5%).

Significant increases in drainage network density due to roads (>20%).

Watershed Conditions

Road Density and Location

<2 mi/sq.mi.; no valley bottom roads.

2-3 mi/sq.mi.; some valley bottom roads.

>3 mi/sq.mi.; many valley bottom roads.

Disturbance History

<15% ECA with no concentration of disturbance in unstable areas or riparian areas.

<15% ECA with some disturbance in unstable areas or riparian areas.

>15% ECA with disturbance concentrated in unstable areas or riparian areas.

Riparian Reserves


Riparian reserves provide shade, LWM recruitment, habitat protection, and connectivity in all subwatersheds. Riparian plant community has the vigor, health, composition and diversity to support riparian reserve values.

Moderate loss of connectivity or function or riparian reserves. Riparian plant community lacking the vigor, health, composition and/or diversity to support riparian reserve values, but is in an upward trend.

Riparian reserves are fragmented with poor connectivity and little protection of habitats. Riparian plant community lacking the vigor, health, composition and/or diversity to support riparian reserve values, and is in a static or downward trend.

1. Items identified as RMO criteria for PACFISH. Data in this table matches PACFISH guidelines and NMFS Table 1 Matrix (NMFS memo dated September 4, 1996).




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