Road Stream Crossing Site EUP_MCW35
Les Cheneaux Islands Watershed, Nunns Creek
St. Ignace Road
Mackinac County
Information collected by:
Site Location
GPS Coordinates: 46.0571611,-84.5639922
T 042N R 002 Sec 09
Fish Passability: Not a Barrier
Structure is NOT Perched
Total Erosion: 0.12 tons/year
Overall Score: 15
Severity: Moderate
Date Inventoried: 6/10/2021
Road Approach - Left
Road Approach - Right
Inlet
Upstream Conditions
Outlet
Downstream Conditions
Representative Reach
Other
Site Sketch
Crossing Information*
Type of Crossing: Bridge
Number of Structures: 1
Structure Shape: Open Bottom Square/Rectangle
Inlet Type: Wingwall Greater than 70 degrees
Outlet Type: At Stream Grade
Structure Material: Concrete
Structure Substrate: Rock
General Conditions: Not new, but no noticeable corrosion, abrasion, chipping, spalling, or cracking. No shape changes such as barrel distortion (bowing, bending, warping), bulging, inlet or outlet damaged.
Structure Interior: Smooth
Is Structure Rusted through? No
Dimensions of Structure: Length 32 ft. Width 48 ft. Height 10 ft.
Percentage Plugged: 61% - 80% Inside
Percentage Crushed: None or 0%
Structure is NOT Perched
Structure Inlet
Water Depth: 2 ft.
Embedded Depth of Structure: 0 ft.
Water Velocity*: 0.1 ft./sec.
Structure Outlet
Water Depth: 1.6 ft.
Embedded Depth of Structure: 2 ft.
Water Velocity*: 0.5 ft./sec.
*Water Velocities were measured 0.5 ft. below the surface (via Flow Meter).
Stream Information
Stream Flow: < Bankfull – The stream channel is more than half filled with water, but is not full.
Stream Flow Type: Perennial (if flowing during the time of assessment.)
Is Scour Pool Present? No
Is Upstream Ponding Present? No
Riffle Information
Water Depth: 2 ft.
Bankfull Width: 20 ft.
Wetted Width: 19 ft.
Water Velocity: 0.1 ft./sec. (measured via Flow Meter)
Dominant Substrate: Organics – decomposing plant material
Road Information
Road Surface: Paved
Owner: State
Road Condition: New Pavement or Well Graded, Same condition as initial placement.
Road Core Integrity: Good (no symptoms of lack of integrity)
Road Width at Culvert: 30 ft.
Location of Low Point: At Stream
Runoff Path: Ditch
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: 1000 ft.
Slope: < 1%
Vegetation: Partial, Ditch has some vegetation and some bare, eroding places.
Erosion Estimate: 0.06 tons/year
Right Approach
Length: 1000 ft.
Slope: < 1%
Vegetation: Partial, Ditch has some vegetation and some bare, eroding places.
Erosion Estimate: 0.06 tons/year
Erosion Information
Estimate of Total Erosion at Crossing: 0.12 tons/year
Summary Information
Fish Passability: Not a Barrier
Is a future visit to this site recommended? No
Were any non-native species observerd at this site? Yes, Spotted Knapweed.
Site Comments: Barrier due to rocks forming a dam under bridge.
*These data are maintained in the Michigan DNR Road Stream Crossing Inventory.