Lonnie’s Has The Oysters, But Deep Pond Has The PEARL

By: Ed Maroney

Topics: Groundwater protection , Wastewater treatment , Waterways

The experimental data buoy PEARL on Deep Pond.  COURTESY PHOTO

ORLEANS Sometimes, floating an idea means just that.

A Massachusetts Institute of Technology faculty member is testing an experimental solar-powered data buoy known as PEARL that's anchored in Deep Pond. Last month, Professor Olivier L. de Weck answered questions from the conservation commission about the device, which is a prototype of a larger version to be deployed in the ocean.

The floating platform, about two meters square, “is taking environmental measurements, measuring data of the air but also the water, including water temperature, humidity, and so forth,” de Weck told the commission Dec. 1. The device had been installed about four weeks earlier off the shore of his South Orleans Road property, with plans to remove it April 15 for further testing at the Woods Hole Oceanographic Institution.

“The ultimate vision of this project,” said de Weck, “would be in the ocean and it would be larger and autonomous underwater vehicles would dock with it.” A data sheet accompanying the application for determination notes that “a full-scale prototype of PEARL could also have the ability to recharge and download data from autonomous underwater vehicles.  ”PEARL – the acronym stands for Platform for Expanding AUV exploRation to Longer Ranges – would transmit data via satellite, cellular or WiFi, depending on its proximity to the shore.

What’s floating in Deep Pond is less complicated. “The only thing under the surface of the water is a static damping plate so that if there’s waves, the platform stays stable,” de Weck said, “plus a standard dinghy anchor.” The buoy installation “doesn’t aerate the water,” the professor said. “It doesn’t have any fluids in it. We think it’s inert as far as the environment is concerned.”

Commissioner Judith Bruce, who lives in the area, suggested to de Weck that he bring the project before the board. At the meeting, she said the buoy had wound up in front of a Towhee Lane property a couple of weeks earlier. “That was kind of a rogue thing,” said de Weck. “I was on the Cape at the time. It was a stormy night. I think the winds dragged the anchor a few tens of feet. I went out and repositioned the buoy. We made sure it was anchored properly this time.”

“You will discover if you’re down here often enough that we have many windy nights, especially through winter we get some real winds that tear through here,” Bruce said. “It would not be a good thing if the anchor repeatedly disturbed the bottom. Having this unit move anchor across the bottom sediments and activating those nutrients back up into the water column can lead to early algae blooms.” The researcher promised to “revisit” the suitability of the anchor to ensure that it would keep the buoy in place.

Bruce also questioned the use of Styrofoam in the buoy. “I’m not a huge fan,” she said. “It does tend to chunk off, either from wind and water action or just from general disintegration. Critters will sometimes chew at it or gnaw at it. I’m wondering if the pontoons might be encased in some nylon fabric, just to make sure to not have chunks of Styrofoam floating around Deep Pond.”

The original plan, de Weck said, was for aluminum pontoons. “I should say the Styrofoam design was kind of a COVID-19-induced shortcut. We just couldn’t get into the shop at MIT for several months. The current Styrofoam is wrapped in plastic cellophane, so the Styrofoam is not directly exposed to the water. We could wrap it with another layer of nylon, and maybe in a color a bit more neutral. I did hear from some of the neighbors about the visual impact.”

“I suspect the abutters would be very pleased if it were dark green or camouflaged,” Bruce said.

“We are definitely willing to do that,” de Weck replied.

Commissioner Walter North said he hoped “the cover on top of the Styrofoam and the layer of plastic will be really tight. I see a lot of that debris all over our beaches after winter storm from docks. Sometimes they’re encased in that polyurethane covering and they, too, disintegrate because of wind and water damage.”

The buoy “has been tested in the pool at MIT,” de Weck said, but is making its first appearance “in nature” in Orleans. Commissioner Jack Kadzik pointed out one of the practical problems the experiment might encounter. “This pond is going to freeze,” he said, to which Bruce added, “There are years when folks are ice skating on it with a thick layer of ice… It has a tendency to freeze. There are other years when there’s no ice at all.”

“We’re monitoring the weather very carefully,” de Weck said. “If it looks like a really cold period and freeze, we would remove the buoy and not let her – sorry, we call her 'her'...”

Commission Chair Ginny Farber said the board “traditionally likes to have this sort of thing out of the water before the pond comes alive. Our date is usually April 1.” Pulling PEARL two weeks earlier “should not make a big difference to us,” de Weck said. In a subsequent email, he wrote that “after 1 April 2021 when the days are longer again, we plan to have PEARL autonomously transition on the ocean (still near shore) from Pleasant Bay to WHOI. After determining that the project was subject to the wetlands protection act, the commission decided that, with the conditions raised during the meeting, further permitting was not required.

“We’re supportive of this project,” said neighbor Judy Wilkins, speaking for herself and Marcia McClellan. “Fortunately, we get to look out at PEARL every day. We’ve had the benefit of watching how carefully the scientists are monitoring the buoy each day. We feel that there will be no issue with neglect of the buoy or issues with the buoy being dragged or causing problems.”

For more information, go to followpearl.mit.edu.