Eye in the sky takes stock of Scarborough beaches

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SCARBOROUGH — The Maine Geological Survey has for the first time used a drone to create detailed images of Western, Ferry and Pine Point beaches.

The goal, according to Peter Slovinsky, a state marine geologist, is to get a better handle on how to manage the coastline in the Scarborough River system.

“We’re using new, low-cost technology, like drones, to develop the best science and help us better understand how sand moves in (this area) of Scarborough,” Slovinsky said.

He said using the drone worked well and provided a very detailed, high-resolution image of the Scarborough River system that, coupled with terrestrial data, can help the state easily keep track of conditions on the three beaches.

The drone flights took place in late August and early September, Slovinsky said, to create a baseline for future monitoring of the beaches impacted by the Scarborough River and the wave action and sea levels in Saco Bay.

In addition, the data collected by the drone also allow the Maine Geological Survey to better understand how the recent beach nourishment project on Western Beach will function in the years to come, Slovinsky said.

Putting new sand on Western Beach, which borders the Prouts Neck Country Club, was part of a $2.3 million U.S. Army Corps of Engineers project to dredge the Scarborough River, which was completed in spring 2015.

The dredging removed about 100,000 cubic yards of sand from the choked-up mouth of the Scarborough River and the area around the harbor used by the town’s commercial fishing fleet.

Along with the drone, the Maine Geological Survey also relied on real-time global positioning and a depth sounder to model both the exposed dunes and beach areas, and the near-shore areas under water at high tide, to create the most accurate elevation models of all three beaches and the river bottom, Slovinsky said.

“We then used the drone to create a qualitative picture of what the area actually looks like,” he added, which will help the Maine Geological Survey create calculations of where the sand is now and where it moves to in the future.

“We know (the dredging and beach nourishment) will have to be done again, so the hope is the data we have collected will help pinpoint key locations for material placement,” Slovinksy said.

Although monitoring the effectiveness of the beach nourishment project on Western Beach was the key goal, he said that using a drone and the other data collection methods also will help the organization better understand how erosion and sea-level rise is impacting the three beaches each year.

In all, according to Slovinksy, the data gathered with the drone’s help will hep local, state and federal officials answer the question of whether beach nourishment, which is often costly, is worth the effort in spots where the coastline is “eroding very fast.”

The drone the Maine Geological Survey used to fly over Western, Ferry and Pine Point beaches is owned and operated by the Greater Portland Council of Governments.

Rick Harbison, a planner and geographic information system specialist at the council, said this week that using the drone allowed Slovinksy “to get an up-to-date aerial base map at a resolution of just a few centimeters per pixel, which is much better than what’s currently available.”

“To do this,” Harbison said, “we flew the drone in a grid over the whole area taking 900-plus images at a height of about 300 feet. We then uploaded the images to a software program that stitches them together and geo-references them into an aerial image that is geographically accurate.”

Slovinksy has worked with Harbison and the drone before to monitor bluff stability in Casco Bay. Since that project and the one in Scarborough has worked out so well, he said, he also expects to use the drone to monitor a recent dredging of Wells Harbor.

A compilation of more than 900 detailed photos of the Scarborough River, Pine Point Beach, left, and Ferry and Western beaches, right, taken by a drone, will help the Maine Geological Survey monitor the condition of the three beaches and the river bottom.