Drone aids in Great Marsh battle

Drones for finding phragmites

[Editor’s Note: Peter Phippen is looking forward to the day when drones can spray the phragmites. Spraying is currently done by a crew with backpacks.]

This post originally appeared on http://ipswich.wickedlocal.com/news/20160904/drone-aids-in-great-marsh-battle.

From 300 feet up the Great Marsh is a colored moonscape: Patches of black water, lateral scars of brown from vehicle tracks, swaths of neon green.

When Peter Phippen looks at the bird’s eye image captured by a drone, he sees time.

It took Phippen and his colleagues three years to map populations of the invasive plant species phragmites across the entire Great Marsh on foot and by boat — work the drone can do in about five days.

Phippen is the coastal resources coordinator for Massachusetts Bays National Estuary Program. He began using the drone last month to aid in mapping the progression of phragmites, which has been spotted growing further and further out into the marsh over the past decade.

The presence of phragmites in the deep marsh is not only troubling because of its potential to wipe out native species and weaken marsh resiliency, but Phippen said it’s also a sign the marsh’s salinity level is declining, most likely because of manmade infrastructure blocking natural water circulation.

Phippen and his team are planning a separate operation to model marsh salinity levels, but for now they are analyzing the drone’s images to identify far-out phragmites stands – clumps of thousands of stems of the tall and hearty plant that grow up to an acre wide.

When Phippen spots a stand, he will mark the location on a map to be sprayed with chemicals this fall. Next summer, Phippen will likely fly the drone out again to verify how the spraying worked and determine whether phragmites stands killed in previous years of spraying have returned.

In the battle against an invasive plant species that spreads quickly through a deep root structure and thousands of airborne seeds, time is a valuable tool.

“It’s amazing,” Phippen said. “The drones are like little beings. You send it out, it figures out where it should fly, it takes pictures that are all overlapping and it puts them together and gives you a map.”

The drone Phippen commissioned in July was owned and operated by Jonathan DeSisto of Drone Air Video Technology, a federally licensed and insured drone pilot who knows how to program the drone to fly a specific course.

When the drone returned to its plywood landing strip in the marsh, DeSisto transferred the data it collected into software that allows people like Phippen to log in to examine the images online.

Beyond phragmites

Though the phragmites control project is the first time Phippen has used a drone in his work, the technology has the potential to make life easier for other Great Marsh researchers.

Phippen said drone mapping could help identify marsh edge erosion, potentially damaging sediment buildup caused by manmade infrastructure and populations of other invasive species like pepper weed.

“The nice thing about the drone is that it takes pictures of everything,” Phippen said. “You might be mapping phragmites but you’re going to see a lot of things that a lot of different people can use for different purposes.”

Pitfalls

Though the drone can slash the time it takes to find significant populations of phragmites, the technology isn’t perfect.

From a few hundred feet up, smaller stands of phragmites blend in with surrounding vegetation. To catch a stand containing 20 or 30 phragmites stems, Phippen estimated the drone would need to fly at an elevation of about 50 feet.

“Then you’ve got a million paths the drone has to go back and forth over because it’s so close,” Phippen explained.

The technology is also costly.

Phippen said hiring a licensed drone operator to map the entire Great Marsh would likely run between $7,000 and $8,000, not including labor costs associated with the time it takes Phippen to comb through the drone’s images in search of phragmites.

The work Phippen is doing with the drone to combat phragmites is being paid for with funds from the Hurricane Sandy Coastal Resiliency Competitive Grant Program. When that money runs out, funding for drone surveillance would have to come from the state.

Still, Phippen says mapping the marsh via drone is a significant advancement.

Gone are the days of trekking through thousands of acres of marshland with a GPS to mark phragmites stands.

But Phippen is still waiting for the day a drone can spray the phragmites — that still takes a crew with backpacks.

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