Fish Passage Site 20503952

Coordinates (dec. deg.): 61.69883°, -149.27676°
Legal Description: S019N001E33
Region: South Central
Road Name: North Mountain Trails Drive

Datum: WGS84
Quad Name / ITM: Anchorage C-7
AWC Stream #: 247-41-10100-2349-3003
Stream Name:


Site Comments: Government Peak Recreation Area access road.

Survey Date: Jun 22, 2021

Survey UPD21-MNT02

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

Overall Fish Passage Rating: Green

Tidal: No
Backwatered: No

Step Pools: Yes
Construction Year:

Site Observations:

  1. Culvert sagging in middle

Comments: Dozer track outside riparian buffer downstream left bank. Grade controls are constructed in pipe. Top of pipe has slight curve with dip in middle. Outlet has damage. 6" fish observed upstream. Sandy depositional areas upstream of culvert, starting about 10m upstream.

Culvert Measurements

ID: 1 Structure Type: Circular pipe (Corrugated steel) Fish Passage Rating: Green
Length(ft): 153.3
Inlet Type: Projecting
Outlet Type: Projecting
Corrugation Depth(in.): 0.5
Corrugation Width(in.): 1.75
Condition Rating(1-5): 5
Approach Angle: 0.0
Sedimentation At Inlet: No
Inlet Substrate: Cobble
Outlet Substrate: Boulder
Width(ft):6.8 6.97
Height(ft):5.21 5.43
Apron Length(ft):
Water Depth(ft): 0.42
Rustline Height(ft):
Substrate Depth(ft):1.6 1.5
Backwatered?: No
Baffles Present: No
Embedded?: Yes
Embedded Depth(ft): 1.5
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 1.7
Culvert Gradient: 1.75%
Max Slope:
Max Slope Length:
  Culvert Observations:
  1. Culvert sagging in middle

Stream Measurements

Stream SubstratesUpstreamDownstream
Stream Slope(deg.):1.73
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)
Width (ft)
Downstream ordinary high water 92.0 4.75
Downstream ordinary high water 119.0 3.78
Downstream ordinary high water 124.0 3.80


Locator ID Culvert
Distance (ft)1
Distance From
Crossing (ft)2
Elevation (ft)
Road Elev 110.55
D/S Thalweg 0.00 92.67
D/S Water Surface Elev 0.00 93.09
D/S Grade Ctrl (Thalweg) (man made from boulders) 19.00 93.91
D/S Water Surface Elev 19.00 94.22
D/S Thalweg 32.00 94.41
D/S Water Surface Elev 32.00 94.72
D/S Grade Ctrl (Thalweg) 35.00 94.58
D/S Water Surface Elev 35.00 95.01
Outlet Invert 38.00 94.59
Outlet Culvert Top 38.00 100.00
D/S Water Surface Elev 38.00 95.10
Inlet Culvert Top 191.30 102.68
Inlet Culvert Invert 191.30 97.51
U/S Water Surface Elev 191.30 97.66
U/S Grade Ctrl (Thalweg) 192.00 97.13
U/S Water Surface Elev 192.00 97.77
U/S Thalweg 221.30 96.93
U/S Water Surface Elev 221.30 97.95


  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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