Consultant outlines beach options

The town will need approximately 980,000 cubic yards of sand to restore its beach in 2015 and provide eight years of advance nourishment. The Longboat Key Town Commission heard five scenarios for a project that needs sand in four locations (see sidebar) at its Jan. 21 workshop, all of which assume that sand-holding groins will eventually be built on the north end.

Town Manager Dave Bullock will continue to work with Olsen Associates to determine how the town will proceed.

Scenario A
Hopper dredge
Estimated cost: $26 million to $32 million

The town could use a Hopper dredge to take sand from its already identified near-shore and offshore sources in what Kevin Bodge, senior vice president of Olsen Associates Inc., described as “the traditional path that’s been done in the past.”

“This completes all of the four areas (where the island needs sand) in one effort, but it brings to mind this concern we have about sand quality,” Bodge said.

The sand’s color is desirable, but its size could cause it to erode at a faster pace than the town would prefer.

Permits are currently in place for most of the project. Still, Bodge said he would not recommend proceeding immediately.

“You could do this project tomorrow but, no, really you can’t. It wouldn’t make sense to place sand up on the north end until you have your structures in place unless you want the sand to wash away like crazy.”

Bodge said he would not recommend bidding this project immediately, either.

“The dredge industry is overbooked, and prices are through the roof,” he said.

The project requires the Hopper dredge to place sand in small, isolated areas that can be difficult to reach, which drives up costs.

Scenario B
Longboat Pass for north end, Hopper dredge for other segments
Estimated cost: $25 million to $31 million

The town could hold off on placing sand at the northern-most tip of the Key and use a Hopper dredge to place sand at the other three segments and later use sand from Longboat Pass for the north end.

“It allows you to build the rest of the project and not have to worry about what’s going on at the north end with the construction of the structures up there,” Bodge said.

Dredging from Longboat Pass is not yet permitted.

Scenario C
Longboat Pass, New Pass and truck haul
Estimated cost: $16 million to $21 million

The town could construct both the north-end and Gulfside Road segments using sand from Longboat Pass. Sand for the south end could come from a new source at New Pass that the town could develop in conjunction with Lido Key, while bringing in sand for the central Key from a high-quality source in Central Florida.

“This maximizes your flexibility,” Bodge said. “You’re using different approaches from different sources in order to best suit your erosion needs in each of your four areas.”
The town would have to obtain permits to dredge from both New Pass and Longboat Pass.

Scenario D
Longboat Pass and truck haul
Estimated cost: $25 million to $30 million

This scenario would build the two north-end segments using dredged sand from Longboat Pass and bring in sand from local sources for the remaining two sites by truck.

An advantage of trucking: Unlike dredging, it doesn’t have major mobilization costs.

“If you take your quantity in half, the price pretty much goes down by half,” Bodge said.

Scenario E
Take all sand from distant offshore sites
Estimated cost: $33 million to $39 million

The most expensive option would bring the highest quality offshore sand from distant sources using a pipeline.

This project is not currently permitted and is approximately 22% to 27% higher than the traditional Hopper dredge scenario. None of the potential sand sources has been developed or permitted.

Click here to view a comparison of sand volume requirements on Longboat Key.

Contact Robin Hartill at [email protected]