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NAVOPLAN

Port Intelligence Brief

Alpena, United States

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68 Verified Intelligence Items

60Verified
Intelligence

41Official
Sources

90%Overall
Confidence

📍

CoordinatesN 45 4' .0012"
W 83 25' .0012"

⚓

Harbor ProfileLake Huron; Great Lakes
Size: Small

🛂

EntranceTidal Range: .00 ft
Depth: 20.99 ft

🕒

Port StatusPort of Entry: Yes
Shelter: Good

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Last UpdateJun 28, 2026
09:30 ET

🧭 Approach & Entrance 7 items

🛟 Shelter & Refuge 6 items

⚠ Local Cautions 6 items

🛒 Crew Rest & Resupply 8 items

☎ Harbor / Authority 7 items 🔒

📡 Contacts & VHF 7 items 🔒

🛥 Marinas 7 items 🔒

⛽ Fuel & Utilities 8 items 🔒

🛂 Clearance & Formalities 5 items 🔒

🚑 Medical & Emergency 7 items 🔒

1 - 10

Current Briefing

Approach & Entrance

Alpena approach intelligence includes pilotage, entrance channel depths, harbor communications, traffic density, anchoring restrictions, and operational cautions for arrival planning.

1 - 1

Verified Intelligence

Federal Navigation Project Depths (Approach & River Segments)

Official Source · Verified Jun 28, 2026

Project depths: 25 ft from deep water in Thunder Bay to 300 ft lakeward of Alpena Light; 24 ft to 700 ft upstream of the light; 23 ft to the Second Avenue bridge; 18.5 ft upstream limit.

95% Confidence

Bridge (Second Avenue) Draw Operation Requirement

Official Source · Verified Jun 28, 2026

Second Avenue bridge (mile 0.3, Thunder Bay River at Alpena) opens on signal only if at least 3 hours advance notice is given to the Dispatcher/Police Department, City of Alpena.

95% Confidence

Entrance Aid: Alpena (Breakwater) Light

Official Source · Verified Jun 28, 2026

Alpena Light (on north breakwater) marks the entrance to Thunder Bay River; listed characteristics in official publications (position and light characteristic noted in Coast Pilot/Light List).

94% Confidence

Shallow Hazards And Wreck Concentration In Thunder Bay

Official Source · Verified Jun 28, 2026

Thunder Bay National Marine Sanctuary protects hundreds of shipwrecks; NOAA notes shallow rocky shoals and wrecks in Thunder Bay present navigation hazards where straying off course can cause grounding/stranding.

93% Confidence

Operational Verification: Tidal/Water Level Monitoring Station

Official Source · Verified Jun 28, 2026

NOAA CO‑OPS maintains water level/datums information for station ID 9075065 (Alpena, MI); use for referencing water levels and datum conversions.

93% Confidence

Harbor Structures, Maintained Channel Length, And Dredging Status

Official Source · Verified Jun 28, 2026

Approximately 700 ft of breakwater structures; ~12,000 ft of maintained channel; last dredged 2017; typical maintenance dredge cycle 5–10 years; maintenance actions planned/funded FY24–FY25.

92% Confidence

Sudden Water Level Oscillation (Meteotsunami / Seiche) Risk

Trusted Secondary Source · Verified Jun 28, 2026

Scientific analysis identifies Alpena (Lake Huron) as a site with documented meteotsunami events and elevated occurrence rates (study reports ~14 meteotsunami events per year at Alpena in the dataset).

78% Confidence