On any given day on Hilton Head Island, the tide can rise or fall more than 8 vertical feet in only 6 hours. That’s a lot of water to move! But how do the tides work? Basically, the tides are controlled by our moon. The average rise & fall of our tide is about 6.5 feet every 6 hours & 13 minutes. For example, if the tide is low at noon, then there will be a high tide at 6:13 pm & low tide again at 12:26 am. This allows the tides to go full cycle about every 28 days, just like our moon. Full and new moons can cause the tide to rise higher due to the moon’s (and sun’s) increased gravitational pull on the earth. These extreme tides are about 20% higher & they are called spring tides, though they can occur any time of the year. One interesting fact is that on the night of a full moon, our high tide will always occur at around 7 pm EST. So, if you see a full moon rising in the evening sky you can be sure that it will be very close to high tide.
The high tide rises to fill South Beach Marina full of water every 12 hours. An 8 foot high tide will bring the water within a couple of feet of the boardwalk. As the tide begins to fall, the water will recede to the outermost edges of the marina, and the surrounding marsh may expose mud flats. This occurs around low tide, and the mud flat created by low tide gives off a brackish odor known as “marsh gas.” Some people think the marsh gas smells like rotten eggs. However, many people find the smell of this "pluff mud" to be organic - which it truly is. To quote Pat Conroy: "I love the marsh. I love the smell of Carolina LowCountry pluff mud! I don’t know of any place that smells like this. It’s a magnificent smell. It’s the smell of where all life comes from. I love that all shrimp, all crab, all oysters are born in the marsh."
Both South Beach and Harbour Town are man-made basins, created over 40 years ago with the development of Sea Pines. These basins must be dredged every few years to remove the natural accumulation of pluff mud. Both basins were dredged in early 2014 resulting in about 8 feet of water at low tide. The basins will need to be dredged again in about 5 years as part of this ongoing process. So, enjoy the rise & fall of the tides. It is a natural, ongoing event as old as the Earth itself. And if you visit at low tide, then sit back and take in the smell of the LowCountry pluff mud, for it is truly the smell of life in the LowCountry.