Closing the Gap in Florida’s Tide Gauge Network

Research professor Clifford Merz and graduate student Dylan Benedict fasten a bracket, holding two tide gauges and a solar panel, to the Marine Science Laboratory. By first installing the equipment over a fixed, known vertical height, they can ensure the device is working properly before it is placed somewhere along the coastline of Florida.

On a sunny day in April, research professor Clifford Merz and graduate student Dylan Benedict climbed into the basket of a forklift behind the University of South Florida College of Marine Science. Their task? Fastening a u-shaped metal bracket, which holds two tide gauges and a solar panel, to the side of the Marine Science Laboratory. The equipment may look unassuming, but the data it collects, once installed at a suitable site, will improve Florida’s ability to forecast sea level rise and related coastal hazards.

Florida’s Tide Gauge Network 

Tide gauges supply high-resolution measurements of water levels that are essential to tracking changes in sea level and informing models of flooding. There are currently 23 gauges around Florida that operate to the standards set by the National Oceanic and Atmospheric Administration (NOAA), which leaves substantial gaps along the longest coastline in the continental United States.

Map showing the 23 tide gauges currently operated by the National Oceanic and Atmospheric Administration (NOAA) along Florida's coastline. Source: NOAA Tides and Currents, Florida Tide Gauge Map.

Gary Mitchum, associate dean and professor at the College of Marine Science, and his lab have partnered with the Florida Flood Hub to expand the tide gauge network around the coast of Florida and close those gaps.  

“Tide gauges operated to NOAA standards keep models honest by providing high-quality data on changes in sea level. State-of-the-art models that are calibrated and validated with such data will be vital in producing the early warnings and assessments of long-term risk needed to protect coastal communities in the future”, says Mitchum.  

With funding from NOAA, up to 80 tide gauges will be positioned strategically around the state. Before installation, Mitchum’s team calibrates each gauge to ensure they function properly in the field. Once installed, the gauges usually require minimal maintenance, with the key activity being replacing batteries once or twice a year. 

A Window into Regional Water Levels 

Mitchum also serves as the chair of the Flood Hub’s Sea Level Change Workgroup, which in 2024 completed the first statewide estimates of sea level rise. The estimates apply to the entire state and supply data that stakeholders can use while planning projects to enhance coastal resilience. Moving forward, data from tide gauges data will provide more detailed information that researchers can use to identify regional variations in sea level at points along Florida’s coastline.  

Tide gauge data can also be used to inform forecasting models that give advanced warning about storm surge during hurricane season, like those provided by the Ocean Circulation Lab at the University of South Florida’s College of Marine Science. 

"The numerical models that support our Unified Water Level Forecast product for Florida and the northern Gulf coasts rely on tide gauge data, which provide accurate initial conditions that are essential for successful storm surge forecasts”, says Yonggang Liu, Associate Professor and Director of the Ocean Circulation Lab.    

Closing the Gaps Through Local Collaboration 

Mitchum attributes the gaps in Florida’s tide gauge network, in part, to the requirements that must be met by sites for long-term, NOAA-quality instruments.  

Ideal locations for tide gauges have an easily accessible, solid, and stable vertical surface that will support a mounting bracket over the water. The location should always have water present; it cannot dry out at low tides. The gauge needs to be within line of sight of established geodetic markers, reference points that mark a precisely surveyed vertical elevation and/or horizontal position. Finally, a participating partner from the local community and a well-lit, secure area discourage vandalism and make it easier to keep an eye on the equipment. 

Geodetic benchmarks, like this one (PID: DM4516) on the seawall behind the College of Marine Science, are reference points that mark a precisely surveyed vertical elevation and/or horizontal position.

These characteristics are important for installing an accurate and sustainable gauge, but they also limit the number of suitable sites. In particular, areas like Florida’s Nature Coast and Big Bend have large swaths of mangroves with no structures or established reference points. 

In these situations, local knowledge of existing infrastructure is helpful. Boat ramps, marinas, or public boardwalks are all examples of sites that might be suitable for a tide gauge.  

Thanks to this project and the resulting increase in measurements of water levels around the state, Florida will be better equipped to estimate local risks arising from acute and chronic hazards, such as storm surge and sea level rise.  

If you know of a potential site for a tide gauge, please reach out to the Flood Hub at floodhub@usf.edu or to Gary Mitchum at mitchum@usf.edu. Both coastal and intracoastal locations are welcomed. All locations will be considered but those that support the development of state-of-the-art numerical models simulating variation in water levels along Florida’s coast will be preferred.  

Reach out to floodhub@usf.edu for a shareable project flyer.