City reports on stormwater management for past season
The city of Sanibel reported that its Public Works Department actively managed the city’s weirs throughout the hurricane season and proactively adjusted levels to manage potential rainfall associated with storm events.
The Sanibel Slough system is the main mechanism for surface water management for portions of Sanibel between Beach Road on the east end and the Chateaux Sur Mer subdivision at its westernmost point. It is used to manage freshwater storage on the island generated by rainfall and maintain the freshwater basins of Sanibel, while protecting properties against rainfall flooding.
The Sanibel Slough and associated water control structures/weirs are not designed to protect against storm surge like the island experienced in Hurricane Ian in 2022 and Tropical Storm Debbie and Hurricanes Helene and Milton this year.
The city continued that the surge associated with each event was enough to overwhelm any barrier island stormwater system and resulted in significant, island-wide flooding. Unlike rainfall which, even during a hurricane, occurs more slowly and over a longer duration, surge causes a rapid rise of a tremendous volume of water from the Gulf and bay that overtops the island from all sides, pushing into the island’s canals and Sanibel Slough. This year, Sanibel was impacted by three major surges within weeks of each other on top of an already saturated ground from a well-above average rainy season.
The widespread flooding caused by the surge during the events was well above the levels of Sanibel’s roads and weir structures for the Sanibel Slough. The levels persisted for significant periods of time (24-plus hours), as it takes time for surge waters to recede.
The city reported that as it prepares for potential storm events, which includes lowering Sanibel Slough water levels when necessary to prepare for rainfall, it is important for residents to monitor local weather forecasts and prepare properties accordingly. Unfortunately, there is no way to prevent island flooding from the surges that may occur from tropical storms and hurricanes. Monitor the city’s information releases and follow guidance from authorities regarding evacuations or emergency orders.
The Public Works Department will continue to proactively evaluate and respond to issues with the stormwater system, in accordance with the city’s weir policy. For questions related to the city’s stormwater infrastructure, contact sanpw@mysanibel.com.
To view the slides of the Milton and stormwater management report presented to the Sanibel City Council at its November meeting, visit https://mysanibel.legistar.com/View.ashx?M=F&ID=13547484&GUID=342BC5E6-2761-4B67-B004-27BE41F0EEFE.
For more information about storm surge, visit the National Hurricane Center at https://www.nhc.noaa.gov/surge/.