Lake Worth Lagoon
Altered Inlet Could Have Catastrophic Storm Surge
By Eliot Kleinberg
February 16, 2008
Changes to the Boynton Inlet now being studied could make the already-profound surge from a "storm of the century" downright catastrophic, a consultant's reports suggests.
Members of the committee looking to improve safety at the narrow and treacherous inlet suggested Friday the grim projections could be a deal-breaker. Applied Technology & Management, a West Palm Beach consultant hired by Boynton Beach, came up with a range of options for the inlet. They include:
- Widening the opening from 100 to 300 feet.
- Revamping the southern jetty.
- Dredging the inlet to deepen it by 5 to 10 feet.
- Dredging shoals just outside the inlet to reduce a draft that creates offshore waves, which buffet boats and have swamped some.
The most sweeping changes proposed would result in an increased surge from the kinds of devastating storms that happen once in 100 years, the consultant said.
The changes could add nearly 2 1/2 feet to the almost 9-foot surge estimates say such a storm could send through a wider, deeper inlet. Storm-driven waves would compound the surge.
"The surge effects are make-or-break questions," Inlet Steering Committee member Tom Warnke told the meeting.
More than 11 feet of water could roar into the Intracoastal Waterway, covering streets and yards and rising into pricey homes.
"If any action that we take is going to flood a neighborhood, we're not going to do it," said Donna Brosemer, a political consultant hired by Boynton Beach to chair the committee. "Or it forces us to look at what the mitigating options are."
Manalapan Vice Mayor Tom Gerrard, whose barrier island town's south end abuts the inlet, said even a 1-foot increase in projected surge would overflow half the town's sea walls. "I would consider that unacceptable,' he said.
Noting the original focus of the study was the safety of boaters, Lantana Town Manager Michael Bornstein said, "You can choose to go in and out of the inlet in a boat. You can't choose to pick up your house."
But Boynton Beach resident Aaron Murphy said that's not the case for people who make a living on the ocean. "A lot of my friends have to go out that inlet," he said.
The study also mentioned placing weirs -- dams placed to regulate flows --at the inlet to slow the outflow of water.
But John Yeend, a local coastal engineer, noted that, in advance of a hurricane projected to bring heavy rains, water managers would be dumping water from the lake down canals and into inlets.
"You close the inlet and I can hear all the valves closing on the (hearts of) the board of directors for the water district," Yeend said.
Ocean Ridge Commissioner-elect Terry Brown noted that if world ocean levels are really rising, the problem could be more profound decades from now.
"Even a couple of inches will make a big difference." Brown told the group. "That's not far-fetched,"
The committee, organized about two years ago by Boynton Beach, is composed of residents of that city and surrounding towns, chosen for their expertise on the inlet.
Boynton Beach paid for the $160,000 consultant's study and will be reimbursed by the South Florida Water Management District.
Board members agreed Friday to go back to their respective municipalities and agencies, and estimate how the numbers will affect them, before meeting again.
Manalapan's Gerrard said his town is already working on its own projections.
"I don't think it's going to be pretty," he said.