Fish Passage Improvement site 30303075

Fish Passage Site 30303075

Coordinates (dec. deg.): 59.04834°, -158.54979°
Legal Description: S013S056W13
Region: Southwest
Road Name: Wihdeon Road

Datum: NAD83
Quad Name / ITM: Dillingham A-7
AWC Stream #: 325-30-10100-2021-3012
Stream Name: Seven Sisters Creek Middle Fork

Elevation:

Site Comments: Stream and Watershed name changed to local name on 11.24.21

Survey Date: Sep 20, 2012

Survey SWA12-DIL13

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: 1999

Site Observations:

Beaver Activity
Culvert is poorly aligned

Comments: Big riprap weir at inlet ponding water upstream. Couldn't measure depth of substrate because of riprap. Does not seem to be any substrate inside pipe except mud. Riprap weir/ramp at outlet also. Mostly backwatered by beaver dam at time of survey. Rated gray because of rock ramp at outlet. Currently backwatered because of beavers.Too deep to wade in places, so no distance measurements on stream widths. All measurements 100+ feet upstream.

Culvert Measurements

ID: 1

Structure Type: Box culvert (Structural aluminum plate)

Fish Passage Rating: Gray

Length(ft): 100.9

Inlet Type: Projecting

Outlet Type: Projecting

Corrugation Depth(in.): 2.0

Corrugation Width(in.): 10.0

Condition Rating(1-5): 5

Approach Angle: 60.0

Sedimentation At Inlet: Yes

Inlet Substrate: Boulder

Outlet Substrate: Boulder

	Inlet	Outlet
Width(ft):	11.6	11.6
Height(ft):	4.0	4.1
Apron Length(ft):
Water Depth(ft):		1.86
Rustline Height(ft):
Substrate Depth(ft):	2.0	2.0

Backwatered?: No

Baffles Present: No

Embedded?: No

Outfall Height: 0.52

Outfall Type: Cascade Over Rip-Rap

Constriction Ratio: 1.32

Culvert Gradient: 0.12%

Max Slope:

Max Slope Length:

Comments: No stream gradient: ponded.Rust line height: N/A. Substrate depths approximate.

Culvert Observations:

Beaver Activity
Culvert is poorly aligned

Stream Measurements

Stream Substrates	Upstream	Downstream
Dominant:	Silt/Clay	Silt/Clay
Subdominant:

Stream Slope(deg.):	0
Stream Flow Stage:	Medium

Stream Width Type	Distance From Crossing (ft)	Stream Width (ft)
Upstream ordinary high water		11.00
Upstream ordinary high water		8.10
Upstream ordinary high water		7.00
Upstream ordinary high water		9.00

Elevations

Locator ID	River Distance (ft)¹	Relative Elevation (ft)
Road Elev		106.85
D/S Thalweg	0.00	95.64
D/S Water Surface Elev	0.00	98.76
D/S Water Surface Elev	28.00	99.26
D/S Tailcrest or 1st Thalweg	28.00	98.16
Outlet Culvert Top	30.00	102.52
D/S Water Surface Elev	30.00	99.28
Outlet Invert (riprap)	30.00	97.42
Inlet Culvert Invert (riprap)	130.90	98.86
U/S Water Surface Elev	130.90	99.30
Inlet Culvert Top	130.90	102.64
U/S Water Surface Elev	136.90	99.65
U/S Grade Ctrl (Thalweg)	136.90	98.99
U/S Thalweg	140.90	98.14
U/S Water Surface Elev	140.90	99.80

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.