Road Stream Crossing Site AUS_CR018

Au Sable River Watershed, East Branch Au Sable River
Scenic Trail
Grayling Twp, Crawford County
Information collected by:
Huron Pines
Site Location
GPS Coordinates: 44.75729 , -84.63112
T27N R03W Sec 11
Owned by State
Fish Passability 0.5
Total Erosion: 1.3784 tons/year
Severity: Moderate
Year Inventoried: 2013
Crossing Information
Type of Crossing: Other
Structure Shape: Pipe Arch,Open Bottom Arch
Inlet Type: Projecting
Outlet Type: At Stream Grade
Structure Material: Metal
Structure Substrate: Gravel
General Conditions: Poor
Multiple Culverts/Spans
4.3 ft.
20 ft.
2.7 ft.
Structure Interior: corrugated
Dimensions of Structure: Length 20 ft. , Width 4.3 ft. , Height 2.7 ft.
Structure Inlet
Water Depth: 2.2 ft.
Water Velocity*: 2 ft./sec.
Structure Outlet
Water Depth: 2.2 ft.
Water Velocity*: 2.1 ft./sec.
*Water Velocities were measured at the Surface (with Float Test)
Stream Information
Stream Flow: Less than Bankfull
Scour Pool: Length 32 ft. , Width 25 ft. , Depth 4.5 ft.
Upstream Pond: Length 55 ft. , Width 26 ft.
Riffle Information
Water Depth: 1.6 ft.
Bankfull Width: 33 ft.
Wetted Width: 30.5 ft.
Water Velocity: 1.92 ft./sec. (Measured with Float Test)
Dominant Substrate: Gravel
Road Information
Gravel County Road
Road Condition: Fair
Road Width at Culvert: 12.5 ft.
Location of Low Point: At Stream
Runoff Path: Roadway
Fill Depth: 2.3 ft.
Slope: More than 1:2
Fill Depth: 2 ft.
Slope: 1:2
Left Approach
Length: 680 ft.
Slope: 1% to 5%
Vegetation: Heavy
LS Factor: 0.532
Erosion: 1.2457 tons/year
Right Approach
Length: 100 ft.
Slope: 1% to 5%
Vegetation: Heavy
LS Factor: 0.38
Erosion: 0.1309 tons/year
Erosion Information
Total Erosion at Crossing: 1.3784 tons/year
Extent of Erosion: Minor
Notes: Minor erosion of undercut bank on left upstream approach.
Location of Erosion
Erosion Dimensions
Eroded Material
Material Eroded
Total Erosion
facing downstream
Reaching Stream?
Left Approach
3 ft.
3 ft.
0.7 ft.
Summary Information
Fish Passability 0.5
Erosion is an area of concern for this site. Impounded water is altering channel geomorphology by making the stream channel condsiderable wider upstream and downstream from the crossing. The water level is at the very top of the main culvert, which is not allowing as much water through as it should
A future visit to this site is recommended. Culverts need to be replaced.
These non-native species were observerd at this site: Spotted Knapweed