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
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
Reaching Stream?
Left Approach
16 ft.
9.5 ft.
0.2 ft.
Left Approach
24 ft.
2.5 ft.
0.2 ft.
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