Sand solutions

 

Sand solutions

 

Date: August 19, 2009
by: Kurt Schultheis | City Editor

 
 

How does Longboat Key maintain its beaches?

Longboat Key Commissioner Gene Jaleski made this question one of his key campaign priorities in the March commission race.

The Village resident even created a Web site, lbkbeaches.com, to spur discussion about the town’s beach-management program.

Last year, Jaleski urged the town to consider beach-renourishment alternatives and questioned why the town’s last project used dark, coarse sand.

And in October 2008, Piedroba Marine Construction LLC officials met with two Longboat Key residents and two commissioners to suggest that there are other beach-renourishment options for the town, including micro dredging.

Micro dredging uses a smaller, more agile dredge to skim off sand shoals that collect just offshore, constantly returning sand to the beach via a dredge pipe.

The town currently renourishes its entire beach every six to eight years, using a Hopper dredge, which dredges sand deposits miles from shore and transports it to the island by barge.

The town’s last beach renourishment, which started in 2005 and concluded in 2006, cost approximately $16 million. The project brought a total 1.79 million cubic yards of sand to the island’s 11 miles of beach.

The next renourishment is scheduled for 2013.
Jaleski said he believes micro dredging or other concepts should be considered as viable alternatives, because substantial sand losses at the north-end and behind The Islander Club need constant renourishment.

But Town Manager Bruce St. Denis and the town’s beach engineering consultant firm, Coastal Planning & Engineering, have stated the town does not have any permits to dredge close to the beach and that using nearby sand to fill hot spots could cause other areas of the beach to lose sand.

Coastal Planning and Engineering Longboat Key Beach Project Manager Doug Mann said the town must use a Hopper dredge because there are no sources of sand coarse enough that are close to the beach.

“Coarser sands will respond better during storms and will result in better storm protection,” Mann said. “The coarser sand just doesn’t move as easily as fine, white, powdery sand.”

And Mann said the town doesn’t dredge New Pass or Longboat Pass for sand because it doesn’t have the permits to do so, and it wouldn’t produce enough sand to counteract the erosion that the beach at North Shore Road is experiencing.

Although Mann says the dual-layered beach used in some high-erosion areas has held the beach, he admits it was not an aesthetic success. Dual-layering places a layer of white sand on top of coarse sand.

Used in four high-erosion areas, Mann said the gray sand rose to the top in about a year’s time in all four areas, which included the north-and-south ends of the Key and areas of beach behind Bayport and The Islander Club.

“We are the first ones to admit that people don’t like the color of the beach,” Mann said. “That’s why we are working to find better sand.”

Mann said the town cannot micro dredge “because it won’t work here.” Sand basins, which refill with sand to continuously renourish beaches in the micro-dredging process, cannot be relied upon to constantly refill with sand, Mann said.

For that reason, Mann said his firm believes structures, such as the groins that will be built behind The Islander Club starting this November, are more efficient and cheaper at holding a beach.

“We believe adding structures will slow the erosion rate down so that it will allow the beach renourishment program to be more cost effective,” Mann said.

The following information reports how several neighboring communities renourish their beaches, what kind of sand they use and how much they spend on their sand.

Mann said his firm did not anticipate the gray sand would be revealed so fast.

And Mann said the loss of beach at North Shore Road is being handled as best as possible.

“You can’t place enough sand up there to handle the erosion rate,” said Mann, who explained the town spent $1 million alone in the last beach project to place additional sand in that area that is now gone.

“There’s nothing wrong with the technology,” Mann said. “But you have to permit a sand basin that holds sand to use for renourishments.”

“And there’s no way to tell how long it will take the basin to refill,” Mann said.

A look at other communities

Manatee County


Charlie Hunsicker, Manatee County director of Manatee County Conservation Lands Management, calls it “dumb luck” that his county is able to use cheaper renourishment practices.

“We are able to renourish by using rich, white sand deposits located near the northern tip of Anna Maria Island by using a vacuum technique known as the cutter-head dredge,” Hunsicker said.

In February, Hunsicker said the county will begin a $12 million beach-renourishment project that will bring 200,000 cubic yards of sand to Coquina Beach. It’s the first major renourishment project for that beach.

Previously, the county has brought 4 million cubic yards of sand to other areas of Anna Maria Island, with a $2.1 million project in 1992-93 and a $1.9 million project in 2002.

Hunsicker has raised the issue of subsidizing the county’s beaches through taxpayers like the town of Longboat Key.
 
The county, like the town of Longboat Key, uses tourist development tax dollars to help pay for its beaches.
But the county relies solely on federal and state grants to help pay for the projects, while Longboat Key has the flexibility of doing projects when necessary, because residents help pay for its cost via two beach millage districts.

“It’s going to slow down our renourishments in the future because of costs,” Hunsicker said. “Escalating costs without escalating revenue means one day the lines are going to cross and we will not be ale to raise the money we need to renourish our beaches.”

Hunsicker has even raised the issue of subsidizing the county’s beaches through the taxpayers like the town of Longboat Key.

City of Sarasota

City of Sarasota engineer Alex Davis Shaw just oversaw the city’s last renourishment project on Lido Beach, which ended in April.

In 1999, the city performed a beach renourishment that included coarser sand to hold the beach.

“From a structural standpoint, it’s better, but we got a lot of concerns from residents,” Davis Shaw said. “So when the U.S. Army Corps (of Engineers) did a project in 2003, we paid to have the sand pushed to make a toe of dark sand and had a backfill of white sand put in.”

The result, Davis Shaw said, is more white sand for residents and protection on the shoreline with darker sand.

The most recent renourishment cost $5 million, a combination of federal, state and tourist funds that placed 465,000 cubic yards of sand on the beach.

The city has permits to use a cutter-head dredge to extract sand close to shore at New Pass, and the city tries to renourish Lido every five to six years.

Sarasota County


Sarasota County Coastal Resources Manager Laird Wreford keeps watch over all of the county’s maintained beaches, which include Manasota Key Public Beach, Blind Pass Park, Casey Key Public Beach, Turtle Beach and the popular Siesta Key Public Beach.

Wreford called the maintenance of Sarasota County beaches “totally different” than Longboat Key’s beach-maintenance program.

Wreford says that the popular white sand that sits on Siesta Key and other parts of Sarasota County beaches is brought to the county naturally.

And it doesn’t cost the county a dime.

“The best, whitest sand we have is on Siesta Public Beach and it holds there and actually accretes because the natural barrier called Point of Rocks acts as a barrier to the sand,” Wreford said. “That one beach, our crown jewel, is not eroding. Its accreting and getting wider and bigger.”

But not all of the county’s beaches are so lucky.
Turtle Beach, just to the south of Siesta Public Beach, has nowhere near the white-sand quality of the county’s “crown jewel” to the north.

“It’s just the luck of the draw,” Wreford said. “You are not going to find that sand we have on Siesta Public Beach anywhere else and that sand isn’t going anywhere.”

Several of the county’s beaches, Wreford said, are in a state of constant flux, though.

“Parts of our public beach have a serious erosion problem,” Wreford said.

But unlike Manatee County, Sarasota County has not done many renourishment projects in the past.

Only one, to be exact.

Two years ago, the county completed an $11 million renourishment project that put down 1 million cubic yards of sand south of Siesta Key.

Although the county doesn’t keep a beach engineer on retainer, it hired Coastal Planning & Engineering to help with the county’s first project.

Wreford said the county paid for about 60% of the project using tourist development tax dollars, while the state paid for approximately 35% of the project.

And about 5% of the project cost was paid for by beachfront homeowners through an annual assessment that will be added to their property taxes for seven years.

Wreford said additional renourishment projects would be discussed in the future, including a mile-long beach project that needs to be done at Manasota Key and a three-mile project further to the south.

City of Venice


City of Venice Public Information Officer Pam Johnson said the city’s beach is renourished every 10 years, with the first renourishment project occurring in 1995 and lasting through 1996.

The city has a contract with the U.S. Army Corps of Engineers, with 90% of the financing coming from state-and-federal sources. The other 10% is used from tourist tax development dollars.

The city, which uses beach consultant Dr. Cliff Truitt to monitor its beaches, performed a $12.1 million renourishment project in 2005-06. That project was made up of $2 million in city-and-state monies, with the rest being financed by the federal government.

The city used some bonds that were issued in 2003 to help pay for the project, a pier renovation, a community center and a park.

The project renourished all 3.3 miles of the beach the city maintains by placing 1 million cubic yards of sand on the shore.

The city’s sand was taken eight to 12 miles offshore by a Hopper dredge and transported to the shore by a barge.

Johnson said powdery, white sand is crucial when the beach is renourished.

Pinellas County

Pinellas County Coastal Coordinator Dr. Nicole Elko isn’t afraid to admit that her county’s beaches aren’t all about the aesthetics.

“Of course, we pride ourselves on our white, sandy beaches, but there is a recognition that our renourished beaches will be a little coarser and a little shellier,” Elko said.

Pinellas County’s beaches are strategically located near several inlets, which allow the county to use the sand that’s dredged to deepen the popular boating channels.

The county has permits it uses every 10 years to dredge the inlets that get filled up with sand that used to be on the county’s beach.

The county, however, also uses sand barged in from several miles away when the entire beach needs to be renourished.

The county completed a $45 million Hopper dredge project in 2005-06 to renourish nine miles of the county’s 35 miles of beach coastline. The project placed more than 2 million cubic yards of sand on the beach.

The county, like Longboat, is in the middle of a sand search and has spent $800,000 to look for sand sites that are closer to its beaches.
 
 




 

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