Inventor Claims His "Sedimeter" Device Could Save Endangered Corals Near Fort Lauderdale

In 1984, Ulf Erlingsson was a PhD student at Uppsala University in Sweden, studying physical geography. There, he designed a device that could measure sediment to a tenth of a millimeter. He patented the invention, and 36 years later Erlingsson, now 55, runs his company Lidorm from Medley, Florida. It sells the device he created all those years ago — now called a Sedimeter.

The Sedimeter is a vertical, foot-long pole, just a half-inch in diameter, that is anchored to the seafloor. It has detectors that can read in real-time how much sediment is in the nearby water. In the past, the Sedimeter has mostly been used for research or in sediment studies for navigation channels. But when he heard that the PortMiami dredging project smothered acres of endangered coral over the past two years, Erlingsson thought of a new use for his invention — saving endangered corals that could be ruined in a similar dredging project set to move forward in Port Everglades. 

“I want to prevent what happened in PortMiami from happening in Port Everglades with this device,” he says.

For two decades, the idea of deepening the port in Fort Lauderdale has been batted around. It would deepen the channel from 42 to 48 feet to accommodate bigger cargo ships. Last month, the U.S. Army Corps of Engineers announced it hadd finished its final review of the project. Supporters hope work can begin in 2017 and be completed in three years. 

In 2014, as PortMiami was dredged and expanded for a similar project, government divers discovered that large numbers of coral were destroyed and smothered in sediment. The Army Corps of Engineers had assured other government officials and environmental groups that replanting the coral and wildlife would protect them from the underwater construction. But it was found that the Army Corps underestimated the amount of coral (particularly the endangered staghorn coral) in the area. As a result, those endangered species of coral were never moved from the impact area.

Local environmental groups like Miami Waterkeeper and the Center for Biological Diversity fear that what happened at the Miami port last year will repeat itself at Port Everglades. 

Erglinsson believes that if his product is installed near the endangered corals in Port Everglades, it can alert workers as they dredge if sediment is falling on the corals. Then workers could stop and either change the way they are dredging or transplant the corals before it’s too late.

“Instead of dredging and seeing how many corals die and then transplant them, I want to prevent them from being smothered in the first place,” Erlingsson says. “The idea is to put the Sedimeter out, receive data in real time, so whoever is monitoring the corals can go check on the problem.”


But it doesn’t look like the Sedimeter will be used to save corals anytime soon. The United States Army Corps, the group behind the PortMiami dredge and charged with dredging Port Everglades, does not agree with Erlingsson. In a study conducted in 2013 by the Army Corps, researchers found that the Sedimeter wasn't accurate enough to be used.

“There needs to be a very fine scale of detail because if one millimeter falls on sensitive habitat, it could have a significant ecological impact,” said Michael Petersen, a spokesperson for the Army Corps. “In a lab test and field test in 2013, our scientists found that it was not a fine scale because of its margin of error.”

Erlingsson could not disagree more. In fact, he's accusing the USACE of falsely claiming that his product doesn't work. He's re-created the study, proving his device accurate to a tenth of a millimeter. He wrote an open letter online laying out problems with the USACE's report. He posted a video of his version on YouTube.

“It’s not about the changing the report but protecting the environment,” Erlingsson stresses.

The Army Corps stands by its findings. “I’m aware of the demonstration on YouTube, but we do stand by the results our scientists put in the report,” Petersen says. He was not aware of other technologies that the Army Corps was looking into using that could measure sediment in real time.

Rachel Silverstein, executive director of Miami Waterkeeper, declined to comment on the Sedimeter but in a statement stressed the consequences of sediment falling on corals. “The corps claims it’s a ‘learning agency,’ but all plans so far show that the corps is not intending to improve its practices in Port Everglades after destroying over 200 acres of reef in Miami,” she said.