May River Update #1

Written by Michele Roldan-Shaw

sk just about anyone around here — old-timers and newcomers alike — why they love the Lowcountry and it's almost guaranteed their answer will include the water. For people in Bluffton, "the water" usually means the May River. You already know you love swimming in it, boating on it, eating seafood from it, or even just watching the sun set over it. But how much do you really know about the way this river was formed, how it operates, and what makes it unique among Atlantic coast estuary systems?

The Bluffton Breeze is proud to introduce a new series called May River Update, in which the ecology of our beloved creeks and marshes will be illuminated by way of speaking to the people who are on the river the most — shrimpers, crabbers, fishermen, oystermen, boaters, kayakers, and other people who know the May on intimate terms.

For Update #1, we would like to present a (very) rough sketch of the geological history of the area. Many eons ago, the Carolina coastline was quite different than it is today. After the gnashing around of some tectonic plates and whatnot during the Paleozoic and Mesozoic Eras, God was just getting warmed up. A giant valley had formed where our Coastal Plain sits today, and during the 65 million years that comprise the Cenozoic Era (the planet's most recent history) the sea level rose and fell at least seven times, causing this valley to be alternately exposed or covered by water. This is known by scientists who have studied certain lines in the sand dunes inland from here which indicate where the ancient coastline used to be. Also, the continental shelf about 60 miles offshore from us indicates where the Eastern shoreline existed 18,000 years ago at the peak of the last ice age. What we now know as wetland, beach, ocean, etc. was once a grassy plain, which accounts for the washing up of fossils such as mastodon teeth and the bones of tapirs, camels, giant sloths, and primitive horses.

But okay, let's get back to the May River. The stage was set by geologic activity that caused the current local topography to be formed. When the sea level settled down to what it is today, it left a finger of water extending inland to fill a little valley, and here we come to a crux of understanding about the May. It is not really a true river in terms of what normally comes to mind — freshwater running from an upland source (such as a glacier or mountain spring) to the sea. Rather, the May River is essentially a tiny branch of the ocean reaching inland. Instead of being like other regions of the Atlantic coast, which are classified as estuaries because they represent the meeting of freshwater rivers with the saltwater ocean, what we have is actually an embayment, defined as an indentation in the coast larger than a cove but smaller than a gulf. That is why the water is so salty, the oysters are so tasty, and the whole ecosystem is so unique. The lack of true freshwater rivers also means that the Lowcountry is the only region of the Atlantic coast that does not inherit pollution from urban areas upstream.

The other major factor which makes this area exceptional is the high tidal amplitude, or the difference in water level between high and low tides. You might have heard about this, but not understood the reason behind the phenomenon. Let's break it down: if you look at a map of the Eastern seaboard, you will see the way it curves inward around the Southern states. This is called the South Atlantic Bight, and the center of it just happens to be the Georgia/South Carolina border. When the tide comes in, a vast amount of water is pushed into a smaller and smaller area, resulting in the 8.5 foot tides we have here. The tidal amplitude near the top of the BIght at Cape Hatteras is just 1.5 feet, while down in the Florida Keys it's a mere 1 foot. Our high tides serve to cleanse the May River and, in a way, make up for the lack of freshwater current by providing tidal ebb and flow.

Although there is no significant source of freshwater input, that doesn't mean there is none at all. According to Bluffton native Ben Turner, owner of Native Guide Kayak Tour Company, the river used to be fed by groundwater springs, also known as artesian wells. However, as development in the area increased and many of the natural wetland areas were filled in, the artesian wells ceased to exist sometime around the 1950's. That leaves just one major source of freshwater input for the May: rainwater run-off. This is the other key point in understanding our river because it highlights the important role we all play in protecting it.

"We've got to watch what goes on the ground because it all runs down to the May River," said Turner. "The oysters cleanse, the tide cleanses, but they can only do so much. It's a small river and it can be affected so easily."

Substances such as fertilizers, oil, and pet waste are all pollutants which get carried down to the river in the form of run-off. Since we have no treatment plant to cleanse storm run-off, a lot of harmful substances go directly into the river. Surprisingly, pet waste is perhaps the single most significant pollutant these days. One of the dangers to humans is that pet waste can contain disease organisms like salmonella and giardia. A small, yet important thing you can do is to simply pick up and throw away your dog's excrement; or better yet, flush it down the toilet so it will eventually find its way to the waste water treatment plant.

How can you wash your car and keep our waters clean? Use soap sparingly. Use a hose nozzle with a trigger to save water. Pour your bucket of soapy water down the sink when you are finished, not in the street. Wash your car on a grassy area so the ground can filter the water naturally. Best of all, take your car to a commercial carwash, especially if you plan to clean your engine or the bottom of your car.

Protecting the May River is essential to maintaining a healthy, thriving marine community of fish, shrimp, crabs, dolphins, birds, plants and people. In Update #2, we will go into the workings of this ecosystem, and especially the role that the marsh plays in providing a breeding ground and nursery from some of our most beloved (and tastiest) sea creatures.