Road Stream Crossing Site EUP_6336564587
Carp River Watershed, Unnamed stream
Coffey trail
Mackinac County
Information collected by:
Superior Watershed Partnership
Site Location
GPS Coordinates: 46.1005541960001,-85.0195755619999
T 043NN R 006W Sec 23
Fish Passability: Barrier at High Flows
Structure is NOT Perched
Total Erosion: 1.57 tons/year
Date Inventoried: 6/10/2020
Crossing Information*
Type of Crossing: Bridge
Number of Structures: 1
Structure Shape: Open Bottom Square/Rectangle
Inlet Type: Other
Outlet Type: At Stream Grade
Structure Material: Wood
Structure Substrate: Mixture
General Conditions: Moderate deterioration from corrosion or abrasion (small rust flakes or indication that rust is slightly deeper than the surface level) or cracking or spalling or chipping (few minor cracks or localized chipping in the concrete). OR minor shape changes (described above).
Structure Interior: Smooth
Is Structure Rusted through? No
Dimensions of Structure: Length 13 ft. Width 19 ft. Height 5.8 ft.
Percentage Plugged: None or 0%
Percentage Crushed: None or 0%
Structure is NOT Perched
Structure Inlet
Water Depth: 0.8 ft.
Embedded Depth of Structure: 0 ft.
Water Velocity*: 0.52 ft./sec.
Structure Outlet
Water Depth: 0.8 ft.
Embedded Depth of Structure: 0 ft.
Water Velocity*: 0 ft./sec.
*Water Velocities were measured 0.8 ft. below the surface (via Float Test).
Stream Information
Stream Flow: < 1/2 Bankfull – The stream channel is less than half filled with water.
Is Scour Pool Present? No
Is Upstream Ponding Present? No
Riffle Information
Water Depth: 1.2 ft.
Bankfull Width: 8 ft.
Wetted Width: 6.2 ft.
Water Velocity: 0.83 ft./sec. (measured via Float Test)
Dominant Substrate: Sand – particles are smaller than a pinhead and feel gritty between fingers
Road Information
Road Surface: Gravel
Owner: Other
Road Condition: New Pavement or Well Graded, Same condition as initial placement.
Road Width at Culvert: 16 ft.
Location of Low Point: At Stream
Runoff Path: Roadway
Embankments
Upstream
Fill Depth: 0 ft.
Slope: Vertical, 0:1, or 90°
Downstream
Fill Depth: 0 ft.
Slope: Vertical, 0:1, or 90°
Approaches
Left Approach
Length: 400 ft.
Slope: 1-5%
Vegetation: Heavy, Ditch is fully vegetated or rip-rapped with no signs of erosion.
Erosion Estimate: 0.85 tons/year
Right Approach
Length: 270 ft.
Slope: 1-5%
Vegetation: Heavy, Ditch is fully vegetated or rip-rapped with no signs of erosion.
Erosion Estimate: 0.53 tons/year
Erosion Information
Estimate of Total Erosion at Crossing: 1.57 tons/year
Location of Erosion | Erosion Dimensions | Eroded Material | Material Eroded | Extent of Erosion | Estimated Erosion | ||
facing downstream | Length | Width | Depth | Reaching Stream? | (tons/year) | ||
Left Downstream Embankment1 | 2 ft. | 4.5 ft. | 3 ft. | Yes | Gravelly Loam | Moderate (corrective actions recommended) | 0.19 |
1Erosion mostly under bridge/at footing
Summary Information
Fish Passability: Barrier at High Flows
Is a future visit to this site recommended? No
Site Comments: Structure velocity taken thru bridge. No embankment because it’s a bridge.
*These data are maintained in the Michigan DNR Road Stream Crossing Inventory.