Fish Passage Site 20601539

Coordinates (dec. deg.): 61.06987°, -151.17418°
Legal Description: S011N011W02
Region: South Central
Road Name: Tyonek Timber Road

Datum: NAD83
Quad Name / ITM: Tyonek A-4
AWC Stream #: 247-20-10030-2001
Stream Name: Bunka Lake outlet

Elevation:

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.

Survey UPDATE-1539

Project Supervisor: Gillian O'Doherty, ADFG
Observers: Mark Eisenman, Robert Pype

Overall Fish Passage Rating: Red

Tidal: No
Backwatered: No

Step Pools: No
Construction Year:


Site Observations:

  1. Culvert gradient red
  2. Constriction ratio gray
  3. Inlet perch
  4. Road Fill (pushed off road by grader)
  5. Culvert is too short
  6. Debris Flow

Comments: Resurvey. Site conditions have changed since 2002 survey and AWC nomination has this site flowing the wrong way. Site no longer has a perch, scour hole most likely filled with road fill. Culvert still Red due to gradient and large inlet perch and debris perch inside culvert.

Culvert Measurements

ID: 1 Structure Type: Circular pipe (Corrugated steel) Fish Passage Rating: Red
 
Length(ft): 30.7
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.): 0.5
Corrugation Width(in.): 3.0
Condition Rating(1-5): 2
Approach Angle: 0.0
Sedimentation At Inlet: Yes
Inlet Substrate: None
Outlet Substrate: Gravel
InletOutlet
Width(ft):2.8 3.1
Height(ft):2.9 2.9
Apron Length(ft):
Water Depth(ft): 0.48
Rustline Height(ft):0.9
Substrate Depth(ft): 0.1
Backwatered?: No
Baffles Present: No
Embedded?: No
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 0.72
Culvert Gradient: 2.21%
Max Slope:
Max Slope Length:
 

Comments: Rust line height taken at outlet.. Inlet invert bent and has a large organic debris inlet perch.
  Culvert Observations:
  1. Culvert gradient red
  2. Constriction ratio gray
  3. Inlet perch
  4. Road Fill (pushed off road by grader)
  5. Culvert is too short
  6. Debris Flow

Stream Measurements

Stream SubstratesUpstreamDownstream
Dominant:Silt/ClayGravel
Subdominant:OrganicCobble
Stream Slope(deg.):
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)		 Stream
Width (ft)
Downstream ordinary high water 100.0 4.10
Downstream ordinary high water 150.0 4.00
Downstream ordinary high water 200.0 3.60

Elevations

Locator ID Culvert
Number		 River
Distance (ft)1		 Distance From
Crossing (ft)2		 Relative
Elevation (ft)
Road Elev 97.50
D/S Grade Ctrl (Thalweg) 0.00 90.74
D/S Water Surface Elev 0.00 90.95
D/S Tailcrest or 1st Thalweg 55.00 92.02
D/S Water Surface Elev 55.00 92.48
Outlet Pool Water Elev 65.00 92.49
Max Pool Depth 65.00 91.22
Outlet Invert (on substrate) 79.00 92.08
D/S Water Surface Elev 79.00 92.56
Outlet Culvert Top 79.00 94.95
Inlet Culvert Top 109.70 95.63
U/S Water Surface Elev 109.70 93.59
Inlet Culvert Invert (on substrate) 109.70 92.67
U/S Grade Ctrl (Thalweg) (Top of Inlet perch, 1st resting habitat) 110.70 94.32
U/S Water Surface Elev 110.70 94.71
U/S Water Surface Elev 118.70 94.86
U/S Thalweg 118.70 93.34

Notes:

  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): 1.4
Comments: Trap set about 15 feet upstream from culvert
 
Gear Type: Minnow Trap (B) Trap Duration(h): 1.4
Comments: Trap set about 20 feet downstream from cuvlert

Fish Observations

Species: juvenile coho salmon Life History: Anadromous
Total Fish Observed: 2 Fish Measured: 2 Fork Lengths (mm) Min: 55 Max: 80 Mean: 67
Collected/Observed by Gear Type: Downstream Minnow Trap (2)  

Questions or comments about this report can be directed to dfg.dsf.webmaster@alaska.gov