Old Dunedin Pass (Big Pass) Channel

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Old Dunedin Pass (Big Pass) Channel - Located in upper Clearwater Harbor.

This pass has capped-off due to a weakening tidal flow and barrier island migration.

NAVIGATION
Since the pass has closed, the lateral daybeacon system has been reversed. When heading west, treat it as though you are heading toward port. Markers will increase as you get closer to the now-closed lagoon. Red daybeacons and Nuns are kept to starboard heading toward the lagoon. Green daybeacons and Cans are kept starboard heading toward the open water of St. Joseph Sound.

It is not part of the intracoastal waterway (ICW), and can be differentiated by the lack of yellow stickers on the markers (yellow stripes, triangles or squares indicate it as an ICW aid) at the intersection.

HYDROGEOLOGY
This is a closed pass which once connected Clearwater Harbor to the Gulf of Mexico. The closing of the pass was caused by several factors: Improvements to Clearwater Pass (Little Pass - historical) including the installation of Florida's West Coast's longest jetty and the re-orientation of Clearwater Pass from a NE-SW to SE-NW alignment, the construction of the memorial causeway, the dredge and fill of Island Estates, and natural growth of Hurricane Pass.

These improvements have essentially stolen hydrologic energy by "encroaching" on the "tidal prism" of Old Big Pass. It became geologically unstable, and "barrier island migration" (phrase describing the process by which sand migrates with the longshore current) has filled-in the pass.

PROCEEDINGS
Currently there is no plan to dredge and re-open big pass. However, it was mentioned as "unlikely, but not off the table" during the first ever St. Joseph Sound Watershed Management meeting. Debate is still occuring among the Marine Scientists and Ecologists whether unrestricted flow through Big Pass and improvements through the Garden Memorial Causeway will improve water quality and seagrass beds.