Longboat commissioners seek north end protection

Greer Island just won’t stay put. 

Aerial photographs from the last seven decades show the uninhabited sandspit — which serves as a barrier protecting properties on the north end of island from wave action — shifting, growing and stretching eastward between Longboat Key and Anna Maria Island.

Boats beached east of the Longboat Key Pass Bridge are supported by sand where, just 10 years ago, there was none.

Longboat commissioners want to do something to stop all that movement. 

“We first and foremost have a reason to protect the houses and buildings on the north end and always will,” said At-Large Commissioner Jim Brown at the Commission's November workshop meeting. “It's not a matter of whether we are going to do something — it's what are we going to do, and how far are we going to go.”

But they do have options. 

Commissioners were presented with four possible structural solutions earlier this month for preventing further erosion on the north end of the island. 

This came in the form of a long-term stabilization plan developed with the help of Albert Browder, a coastal-engineering consultant with Olsen Associates, Inc., who offered the commission advice about how to keep Greer Island stable. 

All of Browder’s proposed structural solutions included installing permeable rock groins, construction far less expensive than the material needed to keep the beach alive: sand. 

Since it won’t be cheap, the Commission agreed that Manatee County, which owns the park at Greer Island, should help pay for what protects its property. 

Commissioners approved the town’s pursuit of permitting for five rock groins (see option four), which would give the town flexibility to choose any one of the following proposals. 

Option one

This option, the cheapest of all structural solutions, includes installing one rock groin just north of the concrete permeable adjustable groins the town built in early 2015 at the end of North Shore Road. 

This project could cost the town about $3.3 million, $2.75 million of which would come from about 50,000 cubic yards of sand. This option would provide the most direct protection and benefit to structures on the north end of the island, namely 360 North Condominiums, Browder said.

Option two

This solution proposes installing two rock groins, adding one north of the proposed barrier in option one in effort to protect the most narrow part of Greer Island. 

This project, which proposes adding sand fill to protect much of the dead mangrove forest on Greer Island, could cost residents about $6 million, almost $5 million of which would come from sand fill. 

Option three

Three rock groins on Greer Island could provide the most protection to the north end of Longboat and prevent against further erosion of the island’s northernmost beach within the next two to four years, according to Browder’s proposal. 

But that protection doesn’t come cheap. It could cost Longboat residents upward of $9 million, more than $7 million of which would come from the approximately 135,000-cubic-yards of sand needed in this project. 

Option four

Referred to as the “comprehensive plan” at the November Commission workshop, this proposal includes the three rock groins and sand from option three and adds two more south of the existing permeable adjustable groins at the end of North Shore Road.

The approximate 45,000-cubic-yards of sand the town may put around these groins could prevent further erosion between Longbeach Condominium and Broadway Street and cost, including groin construction, more than $3 million.