Road Stream Crossing Site AUS_CR119

Au Sable River Watershed, South Branch Au Sable River
Smith Bridge Public Access, M-72
South Branch Twp, Crawford County
Information collected by:
Huron Pines
Site Location
GPS Coordinates: 44.61495 , -84.45557
T26N R01W Sec 29
Owned by State
Fish Passability 0.5
Structure is NOT Perched
Total Erosion: 28.8737 tons/year
Severity: Severe
Year Inventoried: 2013
Crossing Information
Type of Crossing: Bridge
Structure Shape: Open Bottom Square/Rectangle
Inlet Type: Wingwall 10-30 Degree
Outlet Type: At Stream Grade
Structure Material: Metal
Structure Substrate: Gravel
General Conditions: Good
Structure Interior: smooth
Dimensions of Structure: Length 15.5 ft. , Width 86 ft. , Height 12 ft.
Structure is NOT Perched
Structure Inlet
Water Depth: 3.4 ft.
Embedded Depth of Structure: 0 ft.
Water Velocity*: 2.99 ft./sec.
Structure Outlet
Water Depth: 3.5 ft.
Embedded Depth of Structure: 0 ft.
Water Velocity*: 2.86 ft./sec.
*Water Velocities were measured at the Surface (with Float Test)
Stream Information
Stream Flow: Less than Bankfull
Scour Pool: Length 0 ft. , Width 0 ft. , Depth 0 ft.
Upstream Pond: Length 0 ft. , Width 0 ft. , Depth 0 ft.
Riffle Information
Water Depth: 2.4 ft.
Bankfull Width: 89 ft.
Wetted Width: 68.5 ft.
Water Velocity: 3.8 ft./sec. (Measured with Float Test)
Dominant Substrate: Cobble
Road Information
Gravel County Road
Road Condition: Good
Road Width at Culvert: 13 ft.
Location of Low Point: Other
Runoff Path: Ditch
Fill Depth: 0 ft.
Slope: Vertical
Fill Depth: 0 ft.
Slope: Vertical
Left Approach
Length: 930 ft.
Slope: More Than 10%
Vegetation: Partial
LS Factor: 8.666
Erosion: 28.8628 tons/year
Right Approach
Length: 0 ft.
Slope: Less Than 1%
Vegetation: Partial
LS Factor: 0.05
Erosion: 0 tons/year
Erosion Information
Total Erosion at Crossing: 28.8737 tons/year
Extent of Erosion: Minor
Location of Erosion
Erosion Dimensions
Eroded Material
Material Eroded
Total Erosion
facing downstream
Reaching Stream?
Left Ditch
16 ft.
18.5 ft.
0.3 ft.
Left Ditch
11 ft.
5 ft.
0.5 ft.
Summary Information
Fish Passability 0.5
A future visit to this site is recommended. To assess water velocity/ bridge is also extremely rusted
These non-native species were observerd at this site: Spotted Knapweed, Reed Canarygrass?