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The Magenta Line

When you're driving back to the island on Main Road and cross the Limehouse Bridge, one of the twentieth century's engineering marvels spreads out to the right and left below. It's the Atlantic Intracoastal Waterway, of which Charleston Harbor and its feeder waterways are a part. Stretching from New Jersey and around the Florida Keys to Brownsville, Texas, the AIW is a patchwork of lakes, rivers and dredged canals that allows both leisure and commercial boat traffic to travel the eastern seaboard sheltered from more dangerous open ocean, following the famous Magenta Line on navigational maps developed by the National Oceanic and Atmospheric Administration (NOAA).

Although it's a twentieth century development, the roots of the Waterway go back as far as the early eighteenth century, when a fledgling United States government set out to facilitate waterborne trade among the states, still separated by thousands of acres of undeveloped wilderness from trading and shipping centers like Charleston and Savannah in the south and Boston and New York in the north. Part of the southeastern portion of the Waterway, for example, is along the Great Dismal Swamp Canal which crosses the border of Virginia and North Carolina, dug by enslaved labor along a route first surveyed before the Revolution by a young George Washington.

The southeast leg of the IAW

But it wasn't until the early 1900's, as motorized boating became practical, that the first charts were developed and published in a booklet called The Inside Route. It still required a good deal of by-the-pants boating until after World War Two, when the federal government invested millions of dollars in re-surveying, re-dredging, new charts, and a series of mile markers along the entire route of the new Magenta Line. The last section of the AIW was completed in Brownsville in 1949.

Today, the Waterway is busy all year-round with commercial shipping heading for coastal ports from inland mining and manufacturing sites, along with leisure traffic traveling south for the winter and north for the summer - and, of course, for SINHG members, who have enjoyed a day on the water as one of our SINHG Trips for members, exploring this blue thread connecting the Lowcountry to the wider world.

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