Fish Passage Improvement site 20401301

Fish Passage Site 20401301

Coordinates (dec. deg.): 61.53214°, -149.52786°
Legal Description: S017N001W30
Region: South Central
Road Name: West Riverdell Drive

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

Elevation:

Site Comments: None

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 UPD21-WRV01

site photos

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

Overall Fish Passage Rating: Green

Tidal: No
Backwatered: No

Step Pools: No
Construction Year: 2016

Comments: Channel splits into multiple stable channels below the outlet. Steam pipe on right bank is broken. Overflow pipe on river left.

Culvert Measurements

ID: 1

Structure Type: Box culvert (Structural steel plate)

Fish Passage Rating: Green

Length(ft): 71.7

Inlet Type: Projecting

Outlet Type: Projecting

Corrugation Depth(in.): 5.0

Corrugation Width(in.): 14.0

Condition Rating(1-5): 5

Approach Angle: 0.0

Sedimentation At Inlet: No

Inlet Substrate: Boulder

Outlet Substrate: Gravel

	Inlet	Outlet
Width(ft):	18.05	18.2
Height(ft):	5.6	5.69
Apron Length(ft):
Water Depth(ft):		1.16
Rustline Height(ft):	1.2
Substrate Depth(ft):	1.4	1.2

Backwatered?: No

Baffles Present: No

Embedded?: Yes

Embedded Depth(ft): 1.2

Outfall Height: 0.0

Outfall Type: At Stream Grade

Constriction Ratio: 0.9

Culvert Gradient: 0.91%

Max Slope:

Max Slope Length:

Comments: Overflow pipe is present. No water flowing through at time of site visit. Pipe graident in designs 0.90%, Water surface gradient 0.50%, Invert gradient 1.3%.

Stream Measurements

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

Stream Slope(deg.):	1.35
Stream Flow Stage:	High

Stream Width Type	Distance From Crossing (ft)	Stream Width (ft)
Upstream ordinary high water	86.0	26.90
Upstream ordinary high water	108.0	17.24
Upstream ordinary high water	127.0	16.84

Elevations

Locator ID	River Distance (ft)¹	Relative Elevation (ft)
Road Elev (Road surface)		102.86
D/S Thalweg (top of where channel starts braiding)	0.00	94.17
D/S Water Surface Elev	0.00	94.80
D/S Water Surface Elev	15.50	95.02
D/S Thalweg (bottom of rock weir)	15.50	94.18
D/S Water Surface Elev	24.30	95.41
Outlet Invert	24.30	95.71
Outlet Culvert Top	24.30	100.39
D/S Water Surface Elev	25.00	95.37
D/S Thalweg (top of rock weir)	25.00	94.34
Inlet Culvert Invert	99.70	95.15
Inlet Culvert Top	99.70	100.65
U/S Water Surface Elev	99.70	95.74
U/S Water Surface Elev	102.70	95.95
U/S Thalweg	102.70	95.13
U/S Thalweg	129.70	95.51
U/S Water Surface Elev	129.70	95.11

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.