Fish Passage Site 20100609

Coordinates (dec. deg.): 62.57356°, -143.51826°
Legal Description: C009N010E10
Region: South Central
Road Name: Nabesna Road

Datum: NAD83
Quad Name / ITM: Nabesna C-6
AWC Stream #:
Stream Name: Caribou Creek


Site Comments: None

Multiple surveys have been conducted at this site — click on the drop down
arrow to the right of the survey date below to choose a different report for this site.


Project Supervisor: Gillian O'Doherty, ADFG
Observers: Andrew Kastning

Overall Fish Passage Rating: Gray

Tidal: No
Backwatered: Maybe

Step Pools: No
Construction Year:

Site Observations:

  1. Constriction ratio gray
  2. Road bank erosion
  3. Culvert is too short

Comments: This site was assessed by the Copper River Watershed Project.

Culvert Measurements

ID: 1 Structure Type: Circular pipe (Corrugated steel) Fish Passage Rating: Gray
Length(ft): 30.55
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.): 0.5
Corrugation Width(in.): 2.5
Condition Rating(1-5): 2
Approach Angle: 20.0
Sedimentation At Inlet: No
Inlet Substrate: Sand
Outlet Substrate: Cobble
Width(ft):6.2 5.95
Height(ft):5.76 5.13
Apron Length(ft):
Water Depth(ft): 1.08
Rustline Height(ft):2.36
Substrate Depth(ft):0.2 0.3
Backwatered?: Maybe
Baffles Present: No
Embedded?: No
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 0.63
Culvert Gradient: 0.20%
Max Slope:
Max Slope Length:
  Culvert Observations:
  1. Constriction ratio gray
  2. Road bank erosion
  3. Culvert is too short

Stream Measurements

Stream SubstratesUpstreamDownstream
Stream Slope(deg.):1
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)
Width (ft)
Downstream ordinary high water 8.70
Downstream ordinary high water 8.80
Downstream ordinary high water 13.20
Upstream ordinary high water 10.60
Upstream ordinary high water 9.80
Upstream ordinary high water 9.20


Locator ID Culvert
Distance (ft)1
Distance From
Crossing (ft)2
Elevation (ft)
Road Elev 100.16
D/S Tailcrest or 1st Thalweg 0.00 93.16
D/S Water Surface Elev 0.00 93.77
Outlet Pool Water Elev 30.00 93.80
Max Pool Depth 30.00 91.38
Outlet Culvert Top 45.00 97.86
D/S Water Surface Elev 45.00 93.81
Outlet Invert 45.00 92.73
Inlet Culvert Top 75.50 97.92
Inlet Culvert Invert 75.50 92.16
U/S Water Surface Elev 75.50 93.81
U/S Grade Ctrl (Thalweg) 90.50 93.79
U/S Water Surface Elev 90.50 94.04
U/S Water Surface Elev 107.50 94.14
U/S Grade Ctrl (Thalweg) 107.50 92.50
U/S Grade Ctrl (Thalweg) 120.50 93.20
U/S Water Surface Elev 120.50 94.14


  1. River distance is measured continuously throughout the survey reach along the thalweg of the stream.
  2. Measured from each end of the crossing along the thalweg of the stream.

Fish Sampling Efforts

Gear Type: Minnow Trap (A) Trap Duration(h): 6.0
Comments: 2 traps set upstream
Gear Type: Minnow Trap (B) Trap Duration(h): 6.0
Comments: 3 traps set downstream, no fish caught downstream.

Fish Observations

Species: Dolly Varden Life History: Unknown
Total Fish Observed: 2 Fish Measured: 2 Fork Lengths (mm) Min: 85 Max: 91 Mean: 88
Collected/Observed by Gear Type: Upstream Minnow Trap (2)  

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