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City provides update on beach erosion monitoring along Gulf

By Staff | Mar 20, 2018

PHOTO PROVIDED Sanibel Island Monument Survey Map.

The city of Sanibel provided an update today on its efforts relative to the ongoing beach erosion that may be affecting the Gulf Pines, Gulf Shores and West Gulf Drive beaches.

Officials reported that the city has been closely monitoring erosion along a section of beach between Gulf Shores, Gulf Pines and the western portion of West Gulf Drive for the past several months. The area has historically experienced erosion, which in 1996 prompted a beach renourishment project to place over 229,000 cubic yards of sand along 3,400 linear-feet of the shoreline. The specific area is located between the Florida Department of Environmental Protection’s reference monuments R-129 to R-133 on the Sanibel Island Monument Survey Map.

Over the past several weeks, some recovery of sand along the beach in the area has been observed. Additional recovery is anticipated as the beach transitions from its typical winter to summer profiles.

Sanibel’s beaches are dynamic systems and are continuously changing, according to officials. High winds and wave action associated with hurricanes Irma and Nate substantially changed the shoreline in the area. Because they were late-season storms, the beach did not have time to recover before winter winds began producing additional impacts to the beach and shore profile. Strong west and northwest winds associated with cold fronts can erode beaches, moving the sand to adjacent beaches or transporting it to nearshore or offshore sandbars.

Based on the city’s recent observations, it appears that a significant amount of sand remains within the system on adjacent beaches and in nearshore sandbars. The sand typically moves onshore during the spring and summer as prevailing winds shift back to the south/southeast.

The city has an ongoing contract with a coastal engineering firm to conduct annual and post-storm beach profile surveys. Between March and September, the sand between monuments R-129 and R-136 shifted substantially, with accretion between monuments R-129 and R-131 and erosion between R-131.5 and R-135. The area continued to change with the passage of Nate in 2017. Accretion was documented along Gulf Pines and Gulf Shores, but there was little recovery of sand along the properties at the end of West Gulf Drive between monuments R-132 to R-135.

While the city has observed significant erosion along some properties, the city’s coastal engineering consultant believes that no structures are in imminent danger from typical wave conditions and high frequency storm events at this time when considering the current setback from the bluff. Officials reported that the city will continue to monitor the area.

In response to the ongoing erosion in the area, the city has obtained a proposal from a coastal engineering firm to design, engineer and permit a beach renourishment project. The project is being designed and permitted as a precaution to ensure that if an emergency renourishment project is needed, the appropriate permits will be in place. The project design that is proposed by the coastal engineer mirrors that of the project completed in 1996.

At its December meeting, Sanibel City Council approved the scope of work for the project. City staff is currently working with the coastal engineer to finalize the project design and permitting documents.

Additional information will be provided as it becomes available.

For further information, contact Natural Resources Director James Evans at james.evans@mysanbel.com or 239-472-3700, Ext. 376, or city engineer and Public Works Director Keith Williams at keith.williams@mysanibel.com or 239-472-6397, Ext. 507.