Fish Passage Site 20401302

Coordinates (dec. deg.): 61.54164°, -149.52385°
Legal Description: S017N001W30
Region: South Central
Road Name: Marble Way

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

Elevation:

Site Comments: Borough Road

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-MS015

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

Overall Fish Passage Rating: Green

Tidal: No
Backwatered: No

Step Pools: No
Construction Year: 2020


Site Observations:

  1. None of this type

Comments: Pipe #1 is an overflow pipe. Culvert #2 is the primary cuvlert.

Culvert Measurements

ID: 1 Structure Type: Pipe-arch (Structural steel plate) Fish Passage Rating: Black
 
Length(ft): 68.1
Inlet Type: Headwall
Outlet Type: Headwall
Corrugation Depth(in.): 2.0
Corrugation Width(in.): 6.0
Condition Rating(1-5): 5
Approach Angle: 0.0
Sedimentation At Inlet: No
Inlet Substrate:
Outlet Substrate:
InletOutlet
Width(ft):21.3 20.9
Height(ft):6.8 6.8
Apron Length(ft):
Water Depth(ft):
Rustline Height(ft):0.0
Substrate Depth(ft):1.53 1.53
Backwatered?: No
Baffles Present: No
Embedded?: Yes
Embedded Depth(ft): 1.53
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio:
Culvert Gradient: 1.06%
Max Slope:
Max Slope Length:
  Culvert Observations:
  1. None of this type
ID: 2 Structure Type: Pipe-arch (Structural steel plate) Fish Passage Rating: Green
 
Length(ft): 67.73
Inlet Type: Headwall
Outlet Type: Headwall
Corrugation Depth(in.): 2.0
Corrugation Width(in.): 6.0
Condition Rating(1-5): 5
Approach Angle: 0.0
Sedimentation At Inlet: No
Inlet Substrate: Cobble
Outlet Substrate: Gravel
InletOutlet
Width(ft):28.3 28.1
Height(ft):7.8 7.6
Apron Length(ft):
Water Depth(ft): 1.3
Rustline Height(ft):0.0
Substrate Depth(ft):4.03 4.23
Backwatered?: No
Baffles Present: No
Embedded?: Yes
Embedded Depth(ft): 4.03
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 0.78
Culvert Gradient: 1.20%
Max Slope:
Max Slope Length:
 

Comments: The cross section width for cuvlert #1 is 12.17 ft and 17.42 ft for culvert #2. Because the inlets and outlets of the culvert are diagonally mitered, the functional widths are greater than the structual widths. 1 Adult sockeye observed downstream of culvert.
  Culvert Observations:
  1. None of this type

Stream Measurements

Stream SubstratesUpstreamDownstream
Dominant:GravelGravel
Subdominant:Sand/Silt/Clay (legacy)Sand
Stream Slope(deg.):1
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)		 Stream
Width (ft)
Upstream ordinary high water 100.0 35.60
Upstream ordinary high water 138.0 44.70
Upstream ordinary high water 170.0 28.00

Elevations

Locator ID Culvert
Number		 River
Distance (ft)1		 Distance From
Crossing (ft)2		 Relative
Elevation (ft)
D/S Thalweg 0.00 86.87
D/S Water Surface Elev 0.00 88.68
D/S Water Surface Elev 17.00 88.81
D/S Thalweg 17.00 86.57
Outlet Invert (outlet #2) 185.00 90.14
Outlet Invert (outlet #1) 185.00 91.15
Outlet Pool Water Elev (outlet #1) 185.00 91.40
Outlet Pool Water Elev (outlet #2) 185.00 91.44
Outlet Culvert Top (outlet #2) 185.00 97.69
Outlet Culvert Top (outlet #1) 185.00 98.01
Inlet Culvert Top (inlet #2) 252.73 98.50
Inlet Culvert Invert (inlet #2) 252.73 91.53
U/S Water Surface Elev (inlet #2 WS) 252.73 91.94
Inlet Culvert Invert (inlet #1) 253.10 91.87
Inlet Culvert Top (inlet #1) 253.10 98.73
U/S Thalweg 294.73 91.99
U/S Water Surface Elev 294.73 92.83
U/S Water Surface Elev 310.73 93.05
U/S Thalweg 310.73 92.13
U/S Water Surface Elev 338.73 93.14
U/S Thalweg 338.73 92.39
U/S Water Surface Elev 361.73 92.31
U/S Thalweg 361.73 92.35

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