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Treasure Island sand loss normal, experts say

 
Visitors walk along Sunset Beach in Treasure Island just north of the Mansions by the Sea condominium complex on Nov. 10. Recent beach erosion has removed some of the sand pumped onto the beach by Weeks Marine Co. of Covington, La., in a $10.8 million beach renourishment project completed over the summer.
Visitors walk along Sunset Beach in Treasure Island just north of the Mansions by the Sea condominium complex on Nov. 10. Recent beach erosion has removed some of the sand pumped onto the beach by Weeks Marine Co. of Covington, La., in a $10.8 million beach renourishment project completed over the summer.
Published Dec. 11, 2014

TREASURE ISLAND — Visitors to Sunset Beach may be startled to find a large, exposed concrete and rock groin despite a $16 million beach renourishment project completed over the summer.

But city and county officials and beach experts say it is a part of the natural loss and gain of sand along the waterfront that is constantly buffeted by waves, particularly during tropical and winter storms and cold fronts.

In July, Treasure Island had two of its beaches — Sunshine Beach to the north and Sunset Beach to the south — renourished with nearly 300,000 cubic yards of sand from Egmont Shoal. St. Pete Beach's Upham Beach also was renourished at the same time.

The city's cost was $10.8 million, with the rest of the funding coming from state and federal governments.

Two recent cold fronts are being blamed for much of the current sand loss, officials say, with strong waves pulling the sand offshore.

"The beach goes through a stabilization process of erosion and accretion," City Manager Reid Silverboard said. "After the first storm, there is usually an escarpment where the sand has been carved out. We'll go out and knock those down but over time the sand gets redeposited."

Ping Wang, a professor with the University of South Florida's School of Geosciences, who is involved in monitoring Pinellas beaches, agrees the sand loss is normal for the area.

"In the wintertime, there tends to be more loss," he said. "When we get our first storm, it reshapes the construction profile and a lot of sand gets moved into the water."

If the Tampa Bay area sees more storms this winter from the northwest, Wang predicts even more sand will be lost due to big waves and high tides.

The groin on Sunset Beach, installed 30 to 40 years ago to interrupt water flow and halt sand migration, becomes a focal point and an ugly reminder that renourishment is man's way of trying to fight Mother Nature, Wang said.

"Treasure Island is a barrier island and naturally wants to move, but when we build structures on it, we are trying to fight to make it stay in one place," he said.

Andy Squires, an official with the county's coastal management division, said he isn't surprised at the loss of sand so far.

The most recent data he has received, which was gathered in October, before the most recent cold fronts, shows a loss of 17,000 cubic yards at Sunset Beach.

"That's a small percentage of the 215,000 cubic yards we put there," he said. "Of the 100 feet of new beach, we lost about 20 feet, which was expected."

Predicting how much more sand will be lost during the winter is almost impossible, Squires said.

"There are a lot of moving parts so it is hard to predict what it will be," he said.

Wang expects, however, that the recent beach renourishment will last longer than the previous one, in 2010, because of the larger amount of sand used and its coarser consistency.

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Squires would like to see groins installed on Upham Beach, which he described as having one of the worst erosion problems in the county. Permitting and funding is difficult to get for permanent structures, but he hopes to see construction in the next few years.