Fish Passage Site 20501520

Coordinates (dec. deg.): 61.99387°, -149.96294°
Legal Description: S022N004W14
Region: South Central
Road Name: South Silver Salmon Drive

Datum: WGS84
Quad Name / ITM: Anchorage D-8
AWC Stream #: 247-41-10200-2190-3020
Stream Name: Caswell Creek tributary


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-1520

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

Overall Fish Passage Rating: Green

Tidal: No
Backwatered: No

Step Pools: No
Construction Year: 2017

Comments: Culverts replaced in 2017. Culvert reassessment 9/26/18. Lake directly upstream of culvert, stream bank bioengineering downstream from culvert. Old beaver dam complex downstream. 4' overflow culvert present on right hand side of main culvert.

Culvert Measurements

ID: 1 Structure Type: Box culvert (Structural aluminum plate) Fish Passage Rating: Green
Length(ft): 54.3
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.): 2.5
Corrugation Width(in.): 9.0
Condition Rating(1-5): 5
Approach Angle: 30.0
Sedimentation At Inlet: No
Inlet Substrate: Gravel
Outlet Substrate: Gravel
Width(ft):16.0 16.0
Height(ft):4.73 4.73
Apron Length(ft):
Water Depth(ft): 0.62
Rustline Height(ft):
Substrate Depth(ft):
Backwatered?: No
Baffles Present: No
Embedded?: Yes
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio:
Culvert Gradient: 1.34%
Max Slope:
Max Slope Length:

Comments: Stream slope taken from 2011 replacement site plans, not verified, but cuvlert gradient close to 1%. Original replacment was washed out in 2012 flood.

  Culvert Observations:
  1. None of this type
ID: 2 Structure Type: Circular pipe (Corrugated steel) Fish Passage Rating: Black
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.):
Corrugation Width(in.):
Condition Rating(1-5): 4
Approach Angle:
Sedimentation At Inlet: No
Inlet Substrate: None
Outlet Substrate: None
Width(ft):4.0 4.0
Height(ft):4.0 4.0
Apron Length(ft):
Water Depth(ft):
Rustline Height(ft):
Substrate Depth(ft):0.0 0.0
Backwatered?: No
Baffles Present: No
Embedded?: No
Outfall Height:
Outfall Type: Overflow Pipe
Constriction Ratio:
Culvert Gradient:
Max Slope:
Max Slope Length:

Comments: Over Flow pipe

Stream Measurements

Stream SubstratesUpstreamDownstream
Stream Slope(deg.):2.4
Stream Flow Stage:Medium

No stream width data available.


Locator ID Culvert
Distance (ft)1
Distance From
Crossing (ft)2
Elevation (ft)
Road Elev 102.27
Outlet Invert (Overflow culvert) 2 95.86
Outlet Culvert Top (Overflow culvert) 2 99.80
Inlet Culvert Invert (Overflow culvert) 2 97.10
Inlet Culvert Top (Overflow culvert) 2 101.07
D/S Thalweg (End of outlet riffle) 0.00 92.82
D/S Water Surface Elev 0.00 93.44
D/S Thalweg (End of bioengineering) 48.00 93.95
D/S Water Surface Elev 48.00 94.34
D/S Thalweg (Constructed outlet riffle mid point) 66.00 94.23
D/S Water Surface Elev 66.00 94.86
D/S Thalweg 76.00 94.30
D/S Water Surface Elev 76.00 95.16
Outlet Invert (On substrate) 1 91.00 94.78
D/S Water Surface Elev 1 91.00 95.40
Outlet Culvert Top (Taken 1 foot in on top of corrugation) 1 92.00 99.68
Inlet Culvert Top (Taken 1 foot in on top of corrugation) 1 144.30 100.41
Inlet Culvert Invert (On substrate) 1 145.30 95.64
U/S Water Surface Elev 1 145.30 96.37
U/S Grade Ctrl (Thalweg) 148.30 95.41
U/S Water Surface Elev 148.30 96.46
U/S Thalweg 153.80 95.54
U/S Water Surface Elev 153.80 96.51
U/S Thalweg 157.80 94.98
U/S Water Surface Elev 157.80 96.54
U/S Thalweg 168.30 94.60
U/S Water Surface Elev 168.30 96.56
U/S Thalweg (Edge of lake/inlet channel) 175.30 93.64
U/S Water Surface Elev 175.30 96.54


  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

No fish sampling occurred during this survey.

Fish Observations

No fish observations occurred during this survey.

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