Fish Passage Site 20401301

Coordinates (dec. deg.): 61.53214°, -149.52786°
Legal Description: S017N001W30
Region: South Central
Road Name: West Riverdell Drive

Datum: NAD83
Quad Name / ITM: Anchorage C-7
AWC Stream #: 247-50-10300
Stream Name: Cottonwood 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.

Survey UPD21-WRV01

Project Supervisor: Kim Clark, ADFG — Anchorage, AK
Observers: Kim Clark, Michael Mazzacavallo

Overall Fish Passage Rating: Green

Tidal: No
Backwatered: No

Step Pools: No
Construction Year: 2016

Comments: Channel splits into multiple stable channels below the outlet. Steam pipe on right bank is broken. Overflow pipe on river left.

Culvert Measurements

ID: 1 Structure Type: Box culvert (Structural steel plate) Fish Passage Rating: Green
Length(ft): 71.7
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.): 5.0
Corrugation Width(in.): 14.0
Condition Rating(1-5): 5
Approach Angle: 0.0
Sedimentation At Inlet: No
Inlet Substrate: Boulder
Outlet Substrate: Gravel
Width(ft):18.05 18.2
Height(ft):5.6 5.69
Apron Length(ft):
Water Depth(ft): 1.16
Rustline Height(ft):1.2
Substrate Depth(ft):1.4 1.2
Backwatered?: No
Baffles Present: No
Embedded?: Yes
Embedded Depth(ft): 1.2
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 0.9
Culvert Gradient: 0.91%
Max Slope:
Max Slope Length:

Comments: Overflow pipe is present. No water flowing through at time of site visit. Pipe graident in designs 0.90%, Water surface gradient 0.50%, Invert gradient 1.3%.

Stream Measurements

Stream SubstratesUpstreamDownstream
Stream Slope(deg.):1.35
Stream Flow Stage:High
Stream Width Type Distance From
Crossing (ft)
Width (ft)
Upstream ordinary high water 86.0 26.90
Upstream ordinary high water 108.0 17.24
Upstream ordinary high water 127.0 16.84


Locator ID Culvert
Distance (ft)1
Distance From
Crossing (ft)2
Elevation (ft)
Road Elev (Road surface) 102.86
D/S Thalweg (top of where channel starts braiding) 0.00 94.17
D/S Water Surface Elev 0.00 94.80
D/S Thalweg (bottom of rock weir) 15.50 94.18
D/S Water Surface Elev 15.50 95.02
Outlet Invert 24.30 95.71
Outlet Culvert Top 24.30 100.39
D/S Water Surface Elev 24.30 95.41
D/S Thalweg (top of rock weir) 25.00 94.34
D/S Water Surface Elev 25.00 95.37
Inlet Culvert Top 99.70 100.65
Inlet Culvert Invert 99.70 95.15
U/S Water Surface Elev 99.70 95.74
U/S Thalweg 102.70 95.13
U/S Water Surface Elev 102.70 95.95
U/S Thalweg 129.70 95.51
U/S Water Surface Elev 129.70 95.11


  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.

Questions or comments about this report can be directed to