Look to nature for beach renourishment?

By Martie Thompson
editor@floridanewsline.com

It’s summertime — and hurricane season — and on St. Johns County’s 42 miles of beaches, homeowners and beachgoers alike are keeping a wary eye out for tropical activity. The last two hurricane seasons have brought unwelcome visits by hurricanes Matthew and Irma; most would agree that a season without a storm hitting the area would be a relief.

According to Nancy Condron, beach resident and volunteer coordinator for the Mickler’s Landing Turtle Patrol, Hurricane Matthew took out the primary dunes along Ponte Vedra Beach, followed by Hurricane Irma nearly a year later that took out the new sand brought in by residents to renourish the beach after Matthew.

“For years our beach naturally eroded and accreted,” Condron said. “But for the past five years, we’ve seen more erosion than accretion.”

Condron further explained that the natural cycle that existed in the area five to eight years ago and earlier would see some storms take sand away from the beach and others bring sand in. Development, along with a change in the weather cycle, has prevented enough sand from naturally renourishing the beaches.

Condron points to nature as the authority on how to have healthy beaches. For instance, after Hurricane Matthew, many beachside residents brought in sand to shore up their dunes … a good idea, as long as proper sand, compatible with the Department of Environmental Protection’s requirements for dune restoration is used. Unfortunately, riverbed sand, dredged from the St. Johns River, was used in some places. Condron said it contained clay clods, rocks and debris and unlike the area’s natural, coarse coquina sand, is easily compacted.

“This means that dune vegetation, necessary to support the dunes, didn’t grow well. It also hindered sea turtles’ ability to build nests,” Condron said. “We’ve had a large number of false crawls and a low number of successful nests so far this season.”

On top of that, many homeowners improperly graded the sand used in their dune restoration efforts. Instead of a gentle slope at the bottom of the dune and then a steeper slope at the top, an overall steep slope was sometimes attained, which made the dune act as a wall.

Condron said, “When waves dissipate on a gently sloping dune, sand is deposited on the dune. When a wave slams against a seawall or improperly graded dune, it takes sand away. This ends up lowering and eroding the beach.”

Condron feels that education is needed in this regard. She said she understands that people will panic at the thought of losing their home and are sometimes swayed by contractors who are just trying to make money. But she noted that some seawalls are being built farther out than the 20-foot maximum from the structure it is intended to protect. This is considered a “take” of the nesting habitat of the sea turtles, which are covered by the federal Endangered Species Act.

“If we all just follow the rules that protect the sea turtles, we will protect the dunes and also our houses,” Condron said.

For beachgoers, staying off the dunes, as well as the so-called “Conservation Zones,” is a must for healthy beach renourishment. The Conservation Zone extends out 15 feet from the dune vegetation towards the ocean and is where protection is needed so new plants may grow — so beachgoers should be careful to not put chairs or tents or walk in this area.

Condron said that on her walks with the turtle patrol, she does see some natural improvement to the beach since Hurricane Irma.

“We are accreting,” she said. “All of the sand that used to be on our beaches is right off shore and will naturally come back eventually. We now need to have more of the storms come in that bring the sand in rather than take it away.”

 

Photo courtesy Nancy Condron

Another false turtle crawl, possibly due to the sea wall. When waves strike a seawall, they take sand back out to sea with them, lowering the beach, and washing away the eggs.