Focus on details in the sand can help understand beach

Melissa Haneline
The Post and Courier

McCullough explains that "nail holes" are small holes in the sand created when incoming water pushes air out through the sand.

Melissa Haneline
The Post and Courier

On Folly Beach, interpretive naturalist Keith McCullough points out rhomboid-shaped ripples, which give their name to Rhomboid Ripples, a beach walk he will lead July 26 and Aug. 9.

Melissa Haneline
The Post and Courier

Keith McCullough uses a homemade suction device to extract a ghost shrimp, a crustacean responsible for many of the small holes in the sand on the shoreline of beaches.

Melissa Haneline
The Post and Courier

McCullough holds a ghost shrimp that he extracted from the shoreline.

This Fourth of July, you might find yourself out on the beach, enjoying the sun, sand, water and — if you're lucky — a good breeze.

Living on the coast, it's easy to take the beach and its accessibility for granted. It's a place for sunning, swimming, picnics and kite-flying, but we sometimes forget that the beach is an entire ecosystem, too.

Keith McCullough, an interpretive naturalist with the Charleston County Park and Recreation Commission, says that by understanding the small features of the beach that we often tend to overlook, we can build a greater knowledge of, and appreciation for, the way a beach is formed.

"Many small processes are at work to contribute to what we know as the beach," he says. "I just want to help them understand how the beaches are changing and how the things that we do to beaches and things we enjoy about beaches are subject to change under all those factors."

In the coming weeks, McCullough will lead two beach walks called Rhomboid Ripples to give beachgoers an opportunity to dig a little deeper into the sand at Lowcountry beaches.

"The beaches are dynamic environments, they change continually, and we make our presence known on beaches, and I'd like for people to be aware of the different factors at work," he said.

Rhomboid ripples, for example, are features of the sand that can exist on the beach or under water. These repetitive sand formations are best observed on the beach, where it's easy to see the interaction of the sand and water movement.

"Different water speed, movement and direction with sand size and type form different types of ripples," McCullough said. "Rhomboid ripples are sort of a diamond-shaped ripple feature on the sand surface."

Water and wind contribute to varying characteristics that distinguish different types of sand formations, he says.

"There are also linear ripples that are just small ridges that happen one after another," explains McCullough. "Sometimes those linear ripples are criss-crossed, so there are two sets and they form a checkerboard kind of thing. Some people call those ladderback ripples."

On the Rhomboid Ripple Strolls, McCullough will explore beach features large and small.

"I hope to start with many small features of the sand, concentrating on a small area, maybe even drawing a circle in the sand and getting down and close to note small sand features. There are holes in the sand formed by animals," he says.

"Some holes are air pockets and can form little dome areas where air is trapped. Others include blister pockets, air holes and swash lines. As the tide comes up and surging water comes up the beach, it brings material and leaves these lines behind, and you can learn about tidal cycle through these lines," said McCullough.

"When we go out and enjoy large concepts such as the expanse of the ocean, the way the sand feels under our feet, the way the dunes are shaped, we aren't thinking of it all in detail. All of those are built by underlying principles and factors. This (beach walk) is a great opportunity to think about those things."