Fish Passage Site 20401293

Coordinates (dec. deg.): 61.53077°, -149.51842°
Legal Description: S017N001W30
Region: South Central
Road Name: Harness

Datum: NAD83
Quad Name / ITM: Anchorage C-7
AWC Stream #: 247-50-10300-2022
Stream Name: Cottonwood Creek tributary

Elevation:

Site Comments: Downstream channelized through yard, lawn, down to waterline.

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 MSB23-MS026

Project Supervisor: Michael Mazzacavallo, Alaska Department of Fish and Game — Anchorage, AK
Observers: Michael Mazzacavallo, Kat Leavitt, Beth Evers

Overall Fish Passage Rating: Green

Tidal: No
Backwatered: No

Step Pools: No
Construction Year:


Site Observations:

  1. Other, including vibrations, cavitation, etc.

Comments: Large minnow sighted at inlet. Fence upstream sits 0.2ft off of substrate at its lowest point, could be barrier to fish at high water. Downstream severely channelized due to neighborhood.

Culvert Measurements

ID: 1 Structure Type: Circular pipe (Corrugated steel) Fish Passage Rating: Red
 
Length(ft): 51.01
Inlet Type: Projecting
Outlet Type: Headwall
Corrugation Depth(in.): 0.5
Corrugation Width(in.): 3.0
Condition Rating(1-5): 4
Approach Angle: 30.0
Sedimentation At Inlet: No
Inlet Substrate: Cobble
Outlet Substrate: Gravel
InletOutlet
Width(ft):2.35 2.45
Height(ft):2.5 2.0
Apron Length(ft):
Water Depth(ft): 0.0
Rustline Height(ft):0.35
Substrate Depth(ft):0.0 0.4
Backwatered?: No
Baffles Present: No
Embedded?: No
Embedded Depth(ft): 0.0
Outfall Height: 0.0
Outfall Type: Overflow Pipe
Constriction Ratio: 0.0
Culvert Gradient: -6.68%
Max Slope:
Max Slope Length:
 

Comments: Culvert is a drainage pipe; however, the top of outlet was significantly higher then inlet measurement, leading to a negative culvert gradient. This could explain the lack of water flow through the pipe.
  Culvert Observations:
  1. Other, including vibrations, cavitation, etc.
ID: 2 Structure Type: Circular pipe (Corrugated steel) Fish Passage Rating: Green
 
Length(ft): 50.39
Inlet Type: Projecting
Outlet Type: Headwall
Corrugation Depth(in.): 0.5
Corrugation Width(in.): 3.0
Condition Rating(1-5): 4
Approach Angle: 30.0
Sedimentation At Inlet: No
Inlet Substrate: Cobble
Outlet Substrate: Gravel
InletOutlet
Width(ft):2.13 2.08
Height(ft):2.02 1.85
Apron Length(ft):
Water Depth(ft):0.0 0.48
Rustline Height(ft):1.3
Substrate Depth(ft):0.0 0.0
Backwatered?: No
Baffles Present: No
Embedded?: No
Embedded Depth(ft): 0.0
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 0.74
Culvert Gradient: 0.40%
Max Slope:
Max Slope Length:
  Culvert Observations:
  1. Other, including vibrations, cavitation, etc.

Stream Measurements

Stream SubstratesUpstreamDownstream
Dominant:SandSand
Subdominant:CobbleGravel
Stream Slope(deg.):0.21
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)		 Stream
Width (ft)
Downstream ordinary high water 41.0 2.95
Downstream ordinary high water 58.0 2.60
Downstream ordinary high water 91.0 3.10

Elevations

Locator ID Culvert
Number		 River
Distance (ft)1		 Distance From
Crossing (ft)2		 Relative
Elevation (ft)
Road Elev 100.00
U/S Thalweg 0.00 94.72
U/S Water Surface Elev 0.00 95.32
U/S Water Surface Elev 2 5.00 95.33
Inlet Culvert Invert 1 5.00 95.36
Inlet Culvert Top 2 5.00 96.78
Inlet Culvert Top 1 5.00 93.91
Inlet Culvert Invert 2 5.00 94.82
Outlet Invert 2 55.39 94.75
D/S Water Surface Elev 2 55.39 95.23
Outlet Culvert Top 2 55.39 96.58
Outlet Invert 1 56.01 95.10
Outlet Culvert Top 1 56.01 97.32
D/S Thalweg 75.39 94.61
D/S Water Surface Elev 75.39 95.04
D/S Water Surface Elev 135.39 95.03
D/S Thalweg 135.39 94.53

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

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 dfg.dsf.webmaster@alaska.gov