How beach groins protect Longboat Key’s sand

The human-made structures help guide sand movement and hold back currents to preserve beaches.

Enjoy being able to walk along the north end beach of Longboat Key? Manmade beach groins are probably to thank for that.

Beach structures, like groins, are commonly used to build up and maintain sand on beaches. On Longboat Key, groins play important roles in making sure the beaches are preserved.

“Jetties and groins are built perpendicular to the shore to block the movement of sediment along the shore, hold back currents, protect areas from wave forces, guide sand movement and maintain navigation depth,” according to the Federal Emergency Management Agency.

But Assistant Director of Public Works Charlie Mopps said people often confuse groins and jetties.

Simply put, groins are structures that hold sand in place, whereas jetties maintain a channel’s alignment.

Groins are usually built perpendicular to a shoreline. These structures are then able to slow down sediment naturally carried down the shoreline by waves and also protect areas from wave impacts, according to FEMA.