Fish Passage Site 10103542

Coordinates (dec. deg.): 55.60843°, -132.99768°
Legal Description: C072S081E21
Region: Southeast
Road Name: Big Salt Lake Road

Datum: NAD83
Quad Name / ITM: Craig C-3
AWC Stream #:
Stream Name: Unnamed

Elevation:

Site Comments: Near milepost 6. Duke Creek Tributary.

Survey Date: Jul 23, 2017

Survey SEA17-BSL26

Observers: Elizabeth Flory, Kelly Petty

Overall Fish Passage Rating: Gray

Tidal: No
Backwatered: No

Step Pools: Yes
Construction Year:


Site Observations:

  1. Culvert gradient gray

Comments: Borderline embedded, one cutthroat caught upstream. Upstream has some steeper cascades, step pools. Downstream splits around big large woody debris pile with gravel bar. 50ft downstream is 4ft high LWD step. Stream length for gradient calculation a bit short.

Culvert Measurements

ID: 1 Structure Type: Circular pipe (Structural aluminum plate) Fish Passage Rating: Gray
 
Length(ft): 153.0
Inlet Type: Mitered
Outlet Type: Mitered
Corrugation Depth(in.): 2.5
Corrugation Width(in.): 6.0
Condition Rating(1-5): 4
Approach Angle: 15.0
Sedimentation At Inlet: Yes
Inlet Substrate: Boulder
Outlet Substrate: Boulder
InletOutlet
Width(ft):15.3 15.5
Height(ft):8.5 12.5
Apron Length(ft):
Water Depth(ft): 0.25
Rustline Height(ft):0.0
Substrate Depth(ft):6.8 3.0
Backwatered?: No
Baffles Present: No
Embedded?: Yes
Embedded Depth(ft): 3.0
Outfall Height: 0.0
Outfall Type: At Stream Grade
Constriction Ratio: 1.36
Culvert Gradient: 4.14%
Max Slope:
Max Slope Length:
 

Comments: Also concrete headwall at inlet. Constructed step pools inside pipe. Culvert gradient is water surface elevation through pipe, tops of pipes were not surveyed due to safety concerns. Culvert very close to being embedded and rated as an embedded culvert. Not set to within 1% of stream gradient, but actual pipe elevations not taken. Photos show that outlet substrate is being scoured away, rated as Gray for now, but does not currently look like a barrier, but that could change with loss of substrate. Top of culvert length 125'. Miters at each end are about 9'.
  Culvert Observations:
  1. Culvert gradient gray

Stream Measurements

Stream SubstratesUpstreamDownstream
Dominant:BoulderCobble
Subdominant:CobbleBoulder
Stream Slope(deg.):8.51
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)		 Stream
Width (ft)
Upstream ordinary high water 20.0 11.25
Upstream ordinary high water 40.0 12.25
Upstream ordinary high water 60.0 10.25

Elevations

Locator ID Culvert
Number		 River
Distance (ft)1		 Distance From
Crossing (ft)2		 Relative
Elevation (ft)
Road Elev 137.24
D/S Grade Ctrl (Thalweg) 0.00 96.10
D/S Water Surface Elev 0.00 96.28
D/S Grade Ctrl (Thalweg) 41.00 98.15
D/S Water Surface Elev 41.00 98.52
Max Pool Depth 52.00 97.93
D/S Water Surface Elev 52.00 98.63
D/S Water Surface Elev 70.00 98.86
Outlet Invert (end of mitre on substrate) 70.00 98.61
Inlet Culvert Invert (end of mitre on substrate) 214.00 104.66
U/S Water Surface Elev 214.00 105.19
U/S Grade Ctrl (Thalweg) 226.00 105.67
U/S Water Surface Elev 226.00 106.03
U/S Grade Ctrl (Thalweg) 254.00 108.31
U/S Water Surface Elev 254.00 108.70
U/S Grade Ctrl (Thalweg) 275.00 110.24
U/S Water Surface Elev 275.00 110.41
U/S Grade Ctrl (Thalweg) 326.00 113.61
U/S Water Surface Elev 326.00 114.02
U/S Grade Ctrl (Thalweg) 386.00 119.14
U/S Water Surface Elev 386.00 119.64

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

Gear Type: Minnow Trap (A) Trap Duration(h): 1.25
Comments: 50ft upstream, 1 cutthroat
 
Gear Type: Minnow Trap (B) Trap Duration(h): 1.25
Comments: 50ft downstream, no fish

Fish Observations

Species: juvenile cutthroat trout Life History:
Total Fish Observed: 1 Fish Measured: 1 Fork Lengths (mm) Min: 103 Max: 103 Mean: 103
Collected/Observed by Gear Type: Upstream Minnow Trap (1)  

Questions or comments about this report can be directed to dfg.dsf.webmaster@alaska.gov