Road Stream Crossing Site AUS_CR046

Au Sable River Watershed, Au Sable River
Stephan Bridge Rd
Grayling Twp, Crawford County
Information collected by:
Huron Pines
Site Location
GPS Coordinates: 44.67927 , -84.5772
T26N R02W Sec 5
Owned by Private
Fish Passability 0
Total Erosion: 7.4161 tons/year
Severity: Severe
Year Inventoried: 2013
Crossing Information
Type of Crossing: Bridge
Structure Shape: Open Bottom Square/Rectangle
Inlet Type: Other
Outlet Type: At Stream Grade
Structure Material: Concrete
Structure Substrate: Rock
General Conditions: Fair
Structure Interior: smooth
Dimensions of Structure: Length 40 ft. , Width 61.5 ft. , Height 7.5 ft.
Structure Inlet
Water Depth: 1.7 ft.
Water Velocity*: 3.6 ft./sec.
Structure Outlet
Water Depth: 3 ft.
Water Velocity*: 4.76 ft./sec.
*Water Velocities were measured at the Surface (with Float Test)
Stream Information
Stream Flow: Less than Bankfull
Upstream Pond: Length 95 ft. , Width 85 ft.
Riffle Information
Water Depth: 2.3 ft.
Bankfull Width: 95 ft.
Wetted Width: 91 ft.
Water Velocity: 4.76 ft./sec. (Measured with Float Test)
Dominant Substrate: Cobble
Road Information
Paved County Road
Road Condition: Poor
Road Width at Culvert: 28.6 ft.
Location of Low Point: At Stream
Runoff Path: Ditch
Fill Depth: 0 ft.
Slope: Vertical
Fill Depth: 0 ft.
Slope: Vertical
Approaches
Left Approach
Length: 1000 ft.
Slope: 6% to 10%
Vegetation: Heavy
LS Factor: 2.05
Erosion: 1.9382 tons/year
Right Approach
Length: 1000 ft.
Slope: More Than 10%
Vegetation: Heavy
LS Factor: 5.785
Erosion: 5.4695 tons/year
Erosion Information
Total Erosion at Crossing: 7.4161 tons/year
Extent of Erosion: Minor
Notes: Erosion from foot access path on upstream left approach.
Location of Erosion
Erosion Dimensions
Eroded Material
Material Eroded
Total Erosion
facing downstream
Length
Width
Depth
Reaching Stream?
(tons/year)
Left Approach
16 ft.
9.5 ft.
0.2 ft.
no
Gravel
0.0032
Left Approach
24 ft.
2.5 ft.
0.2 ft.
yes
Sand
0.0053
Summary Information
Fish Passability 0
Fish Passage is an area of concern for this site. Extremely high water velocities at the crossing.
A future visit to this site is recommended. To check velocities during normal flow and see how much have decreased.
These non-native species were observerd at this site: Spotted Knapweed