Fish Passage Site 30303074

Coordinates (dec. deg.): 59.04526°, -158.55354°
Legal Description: S013S056W13
Region: Southwest
Road Name: Nerha Drive

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

Elevation:

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

Survey Date: Sep 20, 2012

Survey SWA12-DIL12

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:

  1. Beaver Activity
  2. Hydraulic flows exceeded capacity

Comments: Outlet backwatered by riprap ramp in channel. Culvert set too high. Adult salmon spawning in creek. Debris or beaver dam immediately upstream. Riprap at inlet and outlet. Spawning adults downstream so had to cut long profile short and stream gradient is approx.

Culvert Measurements

ID: 1 Structure Type: Pipe-arch (Structural steel plate) Fish Passage Rating: Gray
 
Length(ft): 74.2
Inlet Type: Mitered
Outlet Type: Mitered
Corrugation Depth(in.): 2.0
Corrugation Width(in.): 6.0
Condition Rating(1-5): 4
Approach Angle:
Sedimentation At Inlet: Yes
Inlet Substrate: Boulder
Outlet Substrate: Boulder
InletOutlet
Width(ft):7.0 7.0
Height(ft):4.8 3.7
Apron Length(ft):
Water Depth(ft): 1.36
Rustline Height(ft):
Substrate Depth(ft): 2.0
Backwatered?: No
Baffles Present: No
Embedded?: No
Outfall Height: 1.43
Outfall Type: Cascade Over Rip-Rap
Constriction Ratio: 1.09
Culvert Gradient: 0.31%
Max Slope:
Max Slope Length:
 

Comments: Rust line not measured: pipe stained. Approach angle not taken. Length is top of miter. Could not find ends of pipe. Substrate depth inlet unknown. Measurement at outlet is minimum. Outfall height is down cascade.
  Culvert Observations:
  1. Beaver Activity
  2. Hydraulic flows exceeded capacity

Stream Measurements

Stream SubstratesUpstreamDownstream
Dominant:Silt/ClayGravel
Subdominant:Organic
Stream Slope(deg.):1.13
Stream Flow Stage:Medium
Stream Width Type Distance From
Crossing (ft)		 Stream
Width (ft)
Downstream ordinary high water 7.80
Downstream ordinary high water 6.00
Downstream ordinary high water 6.50

Elevations

Locator ID Culvert
Number		 River
Distance (ft)1		 Distance From
Crossing (ft)2		 Relative
Elevation (ft)
Road Elev 103.01
D/S Grade Ctrl (Thalweg) (top of riffle) 0.00 94.74
D/S Water Surface Elev 0.00 95.47
D/S Grade Ctrl (Thalweg) 31.00 95.28
D/S Water Surface Elev 31.00 95.88
D/S Grade Ctrl (Thalweg) (log) 68.00 95.71
D/S Water Surface Elev 68.00 96.24
D/S Water Surface Elev 82.00 96.30
D/S Thalweg (pool) 82.00 94.55
D/S Grade Ctrl (Thalweg) (scour pool outlet) 90.00 95.49
D/S Water Surface Elev 90.00 96.31
D/S Water Surface Elev 102.00 96.44
D/S Thalweg (bottom of scour pool max depth) 102.00 95.37
D/S Thalweg (bottom of cascade) 104.00 95.96
D/S Water Surface Elev 104.00 96.62
D/S Tailcrest or 1st Thalweg (top of cascade/tail water control) 115.00 97.08
D/S Water Surface Elev 118.00 97.93
D/S Water Surface Elev 125.00 98.05
Outlet Invert (below miter/on substrate) 125.00 96.69
Outlet Culvert Top 125.00 100.00
Inlet Culvert Top 199.20 100.23
U/S Water Surface Elev 199.20 98.06
Inlet Culvert Invert 199.20 96.20
U/S Grade Ctrl (Thalweg) 209.70 97.74
U/S Water Surface Elev 211.70 98.66

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: Visual Observation, Ground (A)
Comments: Spawning adult salmon observed downstream. No traps set. Species indet.

Fish Observations

No fish observations occurred during this survey.

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