Fish Passage Improvement site 30303063

Fish Passage Site 30303063

Coordinates (dec. deg.): 59.22559°, -158.67389°
Legal Description: S011S056W14
Region: Southwest
Road Name: Aleknagik Lake Road

Datum: NAD83
Quad Name / ITM: Dillingham A-8
AWC Stream #: 325-30-10100-2031-3051
Stream Name: Silver Salmon Creek

Elevation:

Site Comments: None

Survey Date: Sep 18, 2012

Survey SWA12-DIL01

site photos

Project Supervisor: Gillian O'Doherty, Alaska Department of Fish and Game — Anchorage, AK
Observers: Gillian O'Doherty, Mark Eisenman

Overall Fish Passage Rating: Gray

Tidal: No
Backwatered: No

Step Pools: No
Construction Year:

Site Observations:

Constriction ratio gray
Culvert is too short
Road bank erosion

Comments: 1/4 mile from location. NHD is wrong. Velocity in pipe very high. Had to walk in 18"-deep water. Same amount of substrate through entire pipe.

Culvert Measurements

ID: 1

Structure Type: Pipe-arch (Structural steel plate)

Fish Passage Rating: Gray

Length(ft): 50.4

Inlet Type: Mitered

Outlet Type: Mitered

Corrugation Depth(in.): 2.0

Corrugation Width(in.): 6.0

Condition Rating(1-5): 3

Approach Angle: 0.0

Sedimentation At Inlet: No

Inlet Substrate: Gravel

Outlet Substrate: Gravel

	Inlet	Outlet
Width(ft):	10.5	10.5
Height(ft):	6.4	6.0
Apron Length(ft):
Water Depth(ft):		1.48
Rustline Height(ft):	2.2
Substrate Depth(ft):	0.4	1.0

Backwatered?: No

Baffles Present: No

Embedded?: No

Outfall Height: 0.0

Outfall Type: At Stream Grade

Constriction Ratio: 0.73

Culvert Gradient: 0.94%

Max Slope:

Max Slope Length:

Comments: Top of miter length = 33.1.

Culvert Observations:

Constriction ratio gray
Road bank erosion
Culvert is too short

Stream Measurements

Stream Substrates	Upstream	Downstream
Dominant:	Gravel	Cobble
Subdominant:	Cobble	Gravel

Stream Slope(deg.):	0.96
Stream Flow Stage:	High

Stream Width Type	Distance From Crossing (ft)	Stream Width (ft)
Upstream ordinary high water	80.0	13.00
Upstream ordinary high water	100.0	16.00
Upstream ordinary high water	150.0	14.10

Elevations

Locator ID	River Distance (ft)¹	Relative Elevation (ft)
Road Elev		100.78
D/S Thalweg	0.00	90.79
D/S Water Surface Elev	0.00	92.39
D/S Thalweg	20.00	91.42
D/S Water Surface Elev	20.00	92.82
D/S Water Surface Elev	31.50	92.75
Outlet Invert (substrate)	31.50	91.27
Outlet Culvert Top	40.00	97.49
Inlet Culvert Top	73.10	97.80
U/S Water Surface Elev	82.10	92.80
Inlet Culvert Invert (substrate)	82.10	91.24
U/S Thalweg	107.10	91.81
U/S Water Surface Elev	107.10	92.97
U/S Water Surface Elev (sg)	132.10	93.04
U/S Thalweg	132.10	91.46
U/S Water Surface Elev (sg)	211.10	93.97

Notes:

River distance is measured continuously throughout the survey reach along the thalweg of the stream.
Measured from each end of the crossing along the thalweg of the stream.