Fish Passage Improvement site 20401289

Fish Passage Site 20401289

Coordinates (dec. deg.): 61.60078°, -149.34192°
Legal Description: S018N001E31
Region: South Central
Road Name: East Larch Drive

Datum: NAD83
Quad Name / ITM: Anchorage C-7
AWC Stream #: 247-50-10300-2039
Stream Name: Cottonwood Creek tributary

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 MSCS1-CT138

site photos

Observers: Edward Weiss, Doug Hill

Overall Fish Passage Rating:

Tidal: No
Backwatered: No

Step Pools:
Construction Year:

Comments: Ice damming & overflow in winter (according to local landowner);deep fine sediments in stream channel-flows through hummocks of bog; riffle at culvert outlet, then slower deep sediment area,then narrows to 2-3' with gravel

Culvert Measurements

ID: 1

Structure Type: Circular pipe (Corrugated Metal)

Fish Passage Rating:

Length(ft): 40.3

Inlet Type: Projecting

Outlet Type:

Corrugation Depth(in.): 0.5

Corrugation Width(in.): 2.67

Condition Rating(1-5):

Approach Angle:

Sedimentation At Inlet:

Inlet Substrate: Sand

Outlet Substrate: Sand

	Inlet	Outlet
Width(ft):	2.5	2.5
Height(ft):	2.5	2.1
Apron Length(ft):
Water Depth(ft):	0.35	0.38
Rustline Height(ft):
Substrate Depth(ft):	0.08	0.12

Backwatered?:

Baffles Present: No

Embedded?: No

Outfall Height:

Outfall Type:

Constriction Ratio:

Culvert Gradient: 1.07%

Max Slope:

Max Slope Length:

Culvert Observations:

Improper bedding
Other, including vibrations, cavitation, etc.
Damage associated with ice problems

Stream Measurements

Stream Substrates	Upstream	Downstream
Dominant:	Sand	Sand
Subdominant:

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

Stream Width Type	Distance From Crossing (ft)	Stream Width (ft)
Downstream ordinary high water	50.0	8.00
Downstream ordinary high water	100.0	4.50
Upstream ordinary high water	62.0	8.00
Upstream ordinary high water	106.0	3.00

Elevations

Locator ID	Culvert Number	River Distance (ft)¹	Distance From Crossing (ft)²	Relative Elevation (ft)
Outlet Culvert Top	1			94.01
Inlet Culvert Top	1			94.85
D/S Thalweg		0.00	100.0	90.66
D/S Thalweg		50.00	50.0	90.63
D/S Thalweg (Downstream end of riffle)		76.00	24.0	91.08
Outlet Invert	1	100.00	0.0	91.90
Outlet Thalweg	1	100.00	0.0	91.90
Road Elev		120.00		94.34
Road Elev		120.00		94.83
Inlet Culvert Invert	1	140.00	0.0	92.33
Inlet Thalweg	1	140.00	0.0	92.40
U/S Thalweg		153.00	13.0	91.18
U/S Thalweg		202.00	62.0	92.04
U/S Thalweg		246.00	106.0	92.20

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.

Fish Sampling Efforts

Gear Type: Minnow Trap (A)		Trap Duration(h): -7

Gear Type: Minnow Trap (B)		Trap Duration(h): 16

Fish Observations

Species: juvenile/adult Dolly Varden		Life History: Unknown
Total Fish Observed: 14	Fish Measured: 7	Fork Lengths (mm) Min: 105 Max: 155 Mean: 129
Collected/Observed by Gear Type: Upstream Minnow Trap (14)

Species: juvenile Dolly Varden		Life History: Unknown
Total Fish Observed: 2	Fish Measured: 1	Fork Lengths (mm) Min: 135 Max: 135 Mean: 135
Collected/Observed by Gear Type: Downstream Minnow Trap (2)

Species: juvenile coho salmon		Life History: Anadromous
Total Fish Observed: 30	Fish Measured: 15	Fork Lengths (mm) Min: 70 Max: 103 Mean: 83
Collected/Observed by Gear Type: Downstream Minnow Trap (12) Upstream Minnow Trap (18)

Photos

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