Hyper-local tidal sensors now in use along South Carolina coast

CHARLESTON, S.C. (WCSC) - As the Lowcountry braces for another round of coastal flooding, island towns now have another tool to measure tides.

All along the state’s coast, South Carolina Beach Advocates have been installing a series of water monitoring stations to keep an eye on the tide.

“We are really concentrating our efforts in these areas of spatial gaps between the NOAA tide sensors,” said Nicole Elko, executive director of SCBA. “So here in the Lowcountry and in Beaufort, South Carolina. They [Beaufort] are between the Fort Pulaski gage in Georgia and the Charleston gage, so there’s really no water level data in there, and this project is really helping to fill that gap.”

There are just three NOAA tide gages in South Carolina – one in Charleston, one in Myrtle Beach and another on Pawley’s Island.

Town officials rely on the data they collect for long-term planning, storm preparation and much more, but the data collected isn’t perfectly suited to each locality. And it becomes more and more less perfect the further from the NOAA gages you get.

“We have installed water level sensors in their beach front towns, municipalities and counties to actually measure the water levels surrounding their towns. They’ve never been able to do that before,” Elko said.

These sensors don’t just collect hyper-local data, they relay that data in real time.

“The mayors, who are our board of directors, were talking one day in a board meeting and they said, ‘We are really getting nervous about this nuisance flooding. All this coastal flooding is happening and we don’t know our own water levels,’” Elko said. “We wake up in the middle of the night, we don’t know if our town is going underwater or not. We want to be able to roll over, look at our cell phones, know we’re safe and go back to sleep.”

These sensors appear to the untrained eye to be nothing more than a foot or so of plastic piping and some small solar panels near the water. Installed earlier this year, the sensor for Folly Beach hangs from the Folly River Bridge and is already providing data useful to everyday decisions.

“It’s really going to help me out and my counter parts in public safety just to plan ahead a little better so we will know when to start blocking streets,” said Eric Lutz, flood plain manager at Folly Beach. “Next year we will have enough data built up that it will help us kind of ground truth the predictions that are in regular tide charts.”

Lutz also expects the sensor to help with long-term planning as the threat of a rising ocean becomes a reality more and more each day.

“It will help us plan for hard structures, soft berm structures, where we need to focus our living shorelines,” Lutz said. “It should be able to better back up our requests to local government agencies and outside grant sources to helpfully help us with some community wide projects as well.”

There are around 30 sensors around the South Carolina coast either already installed or waiting to be installed. The company responsible for the sensors and the data collection is Hawaii-based Hohonu. Brian Glazer is the Co-founder and CEO of Hohonu and is also a professor at University of Hawaii.

“All of the wonderful cost saving things that have come out of Silicon Valley haven’t been applied and adapted for environmental science and climate change and oceanography,” Glazer said. “NOAA has a fundamental problem. When they go out and install a tide gage it costs hundreds of thousands of dollars. . .We’re coming in with very cost-efficient technology to provide about the same accuracy in water level, but do it everywhere.”

Elko says it costs about $400,000 for a NOAA sensor, while the Hohonu technology costs around $3,000. The local effort is being supported and funded by the Southeast Coastal and Ocean Observing Regional Association, which is a part of NOAA by extension.

The real-time data isn’t just for customers and government officials. Glazer says it’s available to anyone for free and there’s a good reason for that.

“What launched us in this direction was a funded research project from the National Science Foundation entitled, ‘Democratizing Access to Ocean Observing Technology,’” Glazer said. “So getting the data in the hands of people who need it is engrained in the DNA at Hohonu.”

You can view the tidal data through Hohonu’s website here.

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