The map below is a mashup of bridges, NOAA stations, and NWS Hydrologic stations along the intracoastal waterway. The CSV file for the Hydrologic stations includes links to the live XML data feeds from each station. The NOAA stations are a bit more complicated, but you can use the station ID from the CSV file above to construct an API call. A link to the NOAA documentation is below.
Bridges
Socastee Bridge Water Gauge — The bane of my existence because we can only pass when the water level is below 12′. Historical data show that a month or more may pass before the levels drop below 12′
Marinas Guide to Intracoastal Bridges — All bridges on intracoastal from Marinas. This was the primary source for the bridges data.
NOAA Guide to the Intracoastal — Narrative of the bridges along the intracoastal from Norfolk, VA to Key West, FL
Tides
NOAA Tide Predictions — Text searchable database of tidal prediction points by latitude, longitude and station ID
NOAA Tides API — For computing tides by station
Maps
Sea-Seek — Horrible interface, but a rough guide of what we need google maps to do.
OpenSeaMap — Map of world waterways useful for its open data