Shoreline monitoring in Goodnews Bay, Alaska, will help residents map changes

7/18/2016

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NR: SG-2016/NR312

Goodnews Bay, Alaska—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.

man standing on coastal bluffChris Maio collects GPS measurements on an eroding coastal bluff as part of a shoreline change assessment. Photo by Richard Buzard. Click image for larger version [2.1 MB].

“We really want to know how the shoreline has changed over 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.

Maio is working with geology graduate student Richard Buzard to collect baseline data on how the position of the shoreline in Goodnews Bay in southwestern Alaska has changed.

“This will allow us to assess the community’s resiliency to severe erosion and storm events,” Maio said. “We want to be able to provide Goodnews Bay residents information about what’s been happening here over multiple timescales and some possibilities of what might happen in the future so they have the tools to make decisions on how to respond.”

Baseline data will give residents the ability to develop a record of shoreline change, which can be critical when applying for restoration funding if a disaster occurs. “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.”

Shorelines are more susceptible to erosion when they are exposed to open water and big waves, which can wear away coastal substrate. Loose, unconsolidated shoreline material like silt or volcanic pumice erodes easily. Clays and other consolidated materials that stick together are less prone to erosion. Goodnews Bay’s shoreline has peat and glacial gravel that are pretty resilient to erosion.

However, Goodnews Bay was hit hard by the November storm of 2011. The community had to rebuild several houses and move their airport runway. The storm also revealed that many aspects of the area’s coastal geology have never been studied or mapped before, including the topography, coastal evolution, makeup of the sediment and sea level change. Through Maio and Buzard’s research efforts in Goodnews Bay, they will be able to help the community better prepare for storms like this in the future.

children with monitoring equipmentGeology graduate student Richard Buzard. Photo by Chris Maio. Click image for larger version [2 MB].

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. With those data they can map structures, sediment types and topography above and below the surface. This shotgun approach to sampling, where the researchers collect as much different information as they can on the first field excursion, will allow Maio and Buzard to home in on the most important questions they want to answer in the future. They will visit Goodnews Bay again in August 2016 to collect a second round of GPS samples and sediment cores. Funding for this research comes from 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 (GIS) software, Buzard can align the photos to calculate how different parts of the shoreline have changed, and the rate of change for different areas.

“We are essentially mapping out how the shoreline moves over time,” Buzard said. “There are two ways that can happen. Either sea level goes up and the waterline moves inland, or land gets eroded away. We can measure that using imagery.”

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 used to house the town’s airport, and the other had the school. Buzard plans to use this GIS analysis to project how the shoreline may change in the future.

The team is also looking at sediment cores to learn more about changes in sea level over time. In geologically unaltered areas, the lower the sediment is, the older it is. The size and type of sediment and other material in a core reveals environmental conditions at that time.

Coarse sand layers in a core help the researchers pick out storm events, where surging storm water transports larger sediments into saltmarshes, preserving a record of the storm’s passage. The researchers are also looking for evidence of sea level rise, which is marked in the core by a marine or brackish sediment directly overlying a terrestrial sediment. They can determine the relative timing of the transition between a terrestrial and marine-brackish environment (sea level change) using radiocarbon dating and precise measurements of the depth of the transition.

children with monitoring equipmentRocky Mountain School middle school students Tucker Evans Jr., Brenda Mark and Makayla Lupie collect ground-penetrating radar data to identify subsurface geologic features. Photo by Chris Maio. Click image for larger version [2 MB].

One of the most valuable aspects of the 2015 visit was learning about Goodnews Bay history from residents and elders, Maio and Buzard said. Relationship-building took time, but ultimately led the researchers to insights and data they wouldn’t have access to otherwise.

Gaining acceptance from the village tribal council made it easier to work with members of the community and continues to be useful as the researchers think about how their data makes sense in context. As Maio points out, Goodnews Bay residents—the elders in particular—already know the history of shoreline change and when certain parts of town had to be relocated. “They just don’t have the numbers to get funding for mitigation projects or to predict what might happen in the future,” Maio said.

Maio and Buzard hope the methodology they are putting together can be modified to help learn about other Alaska communities. They began collaborating with a team of researchers on a new project to develop a citizen science program to monitor shoreline change in Bristol Bay.

“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.”

Story by Lauren Frisch

Alaska Sea Grant is a statewide marine research, education, and outreach program, and is a partnership between the University of Alaska Fairbanks and the National Oceanic and Atmospheric Administration. Alaska Sea Grant Marine Advisory agents provide assistance that helps Alaskans wisely use, conserve, and enjoy marine and coastal resources.