Alaska shoreline monitoring helps residents react

July 25, 2016

If a storm wreaks havoc on coastal Goodnews Bay, Alaska, new research by University of Alaska Fairbanks scientists may help the town qualify for relief funding. Efforts to link local perspectives with monitored shoreline changes will vastly improve the understanding of the region’s coastal evolution.

“We really want to know how the shoreline has changed over the past 100 years, how it might have been 500 or 1,000 years ago, and how it might change in the future,” said Chris Maio, a geosciences professor at UAF.

Photo by Richard Buzard. Chris Maio collects GPS measurements on an eroding coastal bluff as part of a shoreline change assessment.

Maio and geology graduate student Richard Buzard are measuring changes in the shoreline in Goodnews Bay in southwestern Alaska to assess resiliency and help the community prepare for future storms.

With baseline data, residents can begin an ongoing record of change, which can be critical when applying for restoration funding. “Shoreline change is so slow that it’s rarely considered a natural disaster like a big earthquake or tsunami,” Buzard explained. “You can’t just say, ‘Oh, this area of land probably isn’t going to be here in 10 years’ and get funding for mitigation based on that. Most of the time, you need to have data showing shoreline change is taking place.”

After the November storm of 2011, residents of Goodnews Bay had to rebuild several houses and move their airport runway. The storm revealed that many aspects of the area’s coastal geology have never been studied or mapped before. Through Maio and Buzard’s research efforts, the community will be able to better prepare for storms in the future.

Maio and Buzard visited Goodnews Bay in summer 2015, where they met with community members and collected sediment cores, GPS measurements and ground-penetrating radar measurements. Those data will help them map structures, sediment types and topography above and below the surface.

They will visit again in August 2016 to collect a second round of GPS measurements and sediment cores. The project is supported by Alaska Sea Grant and the UAF Global Change Student Research Grant with funding from the Cooperative Institute for Alaska Research.

Buzard is using aerial imagery to measure changes to the shoreline that have occurred since the 1950s. By plugging the images into geographic information systems software, Buzard can align the photos to calculate how different parts of the shoreline have changed.

Photo by Chris Maio. Rocky Mountain School middle school students Tucker Evans Jr., Brenda Mark and Makayla Lupie collect ground-penetrating radar data to identify subsurface geologic features.

Initial results show two areas of the shoreline that have experienced significant erosion since the 1950s. Buildings were relocated from both places in the past — one area housed the town’s airport, and the other housed the school.

Using sediment cores, researchers can to learn more about changes in sea level over time. Sea level rise is marked by a marine or brackish sediment directly overlying a terrestrial sediment. The researchers can determine the relative timing of the sea level change using radiocarbon dating and precise measurements of the depth of the transition between terrestrial and marine-brackish sediment.

“One of my main research goals is to collect baseline data sets along the coast of Alaska,” Maio said. “That goal doesn’t have to be focused on communities that are in dire need of being moved. We really just want to get that information as soon as we can so we can start watching and measuring changes, and have a place to start from.”

Read more on the Alaska Sea Grant website.