Fish Passage Site 20401282

Coordinates (dec. deg.): 61.52642°, -149.51424°
Legal Description: S017N001W31
Region: South Central
Road Name: Driveway - 2450 Trapline Drive

Datum: NAD83
Quad Name / ITM: Anchorage C-7
AWC Stream #: 247-50-10300-2012
Stream Name: Cottonwood Slough

Elevation:

Site Comments: Shared driveway for 2450 and 2480 Trapline Dr.

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-MS025

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

Overall Fish Passage Rating: Gray

Tidal: No
Backwatered: No

Step Pools: No
Construction Year:


Site Observations:

  1. Constriction ratio red
  2. Hydraulic flows exceeded capacity

Comments: Channel is a ditch, cannot collect constriction ratio.

Culvert Measurements

ID: 1 Structure Type: Circular pipe (Structural steel plate) Fish Passage Rating: Gray
 
Length(ft): 40.9
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.): 1.0
Corrugation Width(in.): 3.0
Condition Rating(1-5): 3
Approach Angle: 0.0
Sedimentation At Inlet: No
Inlet Substrate: Gravel
Outlet Substrate: Gravel
InletOutlet
Width(ft):2.58 2.6
Height(ft):2.41 2.41
Apron Length(ft):
Water Depth(ft):0.0 1.53
Rustline Height(ft):2.35
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: 0.21
Culvert Gradient: 0.02%
Max Slope:
Max Slope Length:
  Culvert Observations:
  1. Constriction ratio red
  2. Hydraulic flows exceeded capacity

Stream Measurements

Stream SubstratesUpstreamDownstream
Dominant:SandSand
Subdominant:GravelGravel
Stream Slope(deg.):0.44
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)		 Stream
Width (ft)
Upstream ordinary high water 6.0 10.80
Upstream ordinary high water 40.0 14.00
Upstream ordinary high water 70.0 13.70
Upstream ordinary high water 100.0 12.10

Elevations

Locator ID Culvert
Number		 River
Distance (ft)1		 Distance From
Crossing (ft)2		 Relative
Elevation (ft)
Road Elev 99.84
U/S Thalweg 6.00 94.30
U/S Water Surface Elev 6.00 95.67
U/S Water Surface Elev 139.00 95.14
Inlet Culvert Invert 139.00 94.52
Inlet Culvert Top 139.00 95.90
D/S Water Surface Elev 179.90 95.02
Outlet Invert 179.90 93.49
Outlet Culvert Top 179.90 95.89
D/S Thalweg 336.90 93.02
D/S Water Surface Elev 336.90 94.20

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