A Day at the Shore?

 Sonia Refulio-Coronado , a doctoral candidate in environmental and natural resource economics at the University of Rhode Island, is investigating better statistical techniques to scrutinize which communities access coastal areas for recreation, and how both social and ecological issues, such as water quality, impact those decisions. 

“I think about my own experience, for example, getting to the beach without a car,” says Refulio-Coronado, who grew up in Lima, Peru. “I’m a student, so the situation is temporary for me, but there are other people who have these problems even though everyone is close to Narragansett Bay.” 

Refulio-Coronado began her study by asking two questions: does a person’s race or ethnicity and/or income level influence their decision to travel for recreation in coastal areas, and how does a site’s perceived water quality factor into that decision? As a Consortium-supported graduate student, she first went to the source, surveying visitors to beaches and fishing spots across Narragansett Bay. 

“With surveys, we collect data. However, using them to create a rich dataset is more than challenging; for this reason, we have resorted to other data sources,” she says. “It’s not that the problem doesn’t exist; it’s just that it’s difficult to show it statistically.“

Through surveys, for example, individuals may provide rich descriptions as to why they visited a particular coastal site. Obtaining a survey sample that’s statistically relevant and applicable to a wider body of research, however, can be time-consuming and expensive.

Enter  Dr. Nathaniel Merrill , an environmental economist at the U.S. Environmental Protection Agency investigating how cell phone data can offer large-scale insights on how visitors value the shore with their time and money. 

“We examine travel behavior to understand people’s values around natural resources, and cell phone data solves the problem of needing a recorder all the time,” says Merrill, also one of Refulio-Coronado’s doctoral committee members. “We can combine the cell phone data with on-the-ground methods to reproduce visitation information in terms of number of people affected and hours spent at a location, data we cannot collect on a big scale right now.” 

The cell phone data, which is aggregated and anonymized to protect individual privacy, has been purchased by the U.S. EPA via AirSage, Inc., a location intelligence company. Refulio-Coronado and Merrill use this data to build a visitation dataset. She models how a Rhode Island resident decides to visit a coastal site within the study area, including beaches in Rhode Island and within a 100-mile radius.  

Economists typically select key indicators of human behavior, in this instance how people value coastal sites through spending money to travel, as well as the time they dedicate for that travel. 

Refulio-Coronado uses geolocated cell data, gathered hourly during the summer months of 2018 and 2019, in order to quantify the number of visits to a particular site, or a “point of interest,” as well as the place of residence of the beachgoers. Her study examines over 600 so-called points of interest throughout Rhode Island.

She then examines in aggregate the distances Rhode Island residents travel to enjoy coastal sites, as well as calculate via statistical equations the estimated travel cost based on those same distances. 

“AirSage measures the activity of cell phones over a 24-hour period,” she explains. “At places where people spend more than six hours, they assume that is where they live. I have an Excel sheet that counts the number of visits to a POI.

"Then based on where AirSage assumes beachgoers live, we can extract their income level from the U.S. Census based on the Census Block Group they reside in.

“The value of one’s time depends on income level, and because I know where people come from, I can approximate a total out-of-pocket cost.” 

Another layer of Refulio-Coronado’s work examines how water quality at coastal sites impact the beach which residents visit alongside socioeconomic indicators, measured through data from satellite maps on water clarity. 

“Because we’re dealing with people’s decisions, an indicator has to be something people understand,” she says. “When we’ve asked people what they care about most when visiting a site, water clarity is one of those variables.

“Waters at beaches in the Caribbean are not nutrient-rich, but visitors find them amazing.” 

By establishing evidence-based trends of travel costs in time and money, says Merrill, local and state leaders will be able to make more informed decisions on issues such as coastal accessibility, community exposure to water quality changes and beach closure regulations. 

“I want to see more applied studies using cell data to understand economic valuations of water quality impacts,” he says. “You can imagine using it for impacts of things like wildfires or freshwater harmful algal blooms, but I want to test it, figure out where it breaks down and improve our methods. 

“Sonia’s work is front-running what we want to do.” 

Refulio-Coronado, who plans to finish her doctoral dissertation on human behavior and related issues such as microplastics and per- and polyfluoroalkyl substances (PFAS) sometime in 2023, ultimately wants to develop more complete pictures of communities who lose access to water-based activities because of combined societal and ecological obstacles. 

“We have never examined how different groups of people can be affected by changes in water quality,” she says. “My research is, ‘hey, here is the problem,’ but the other side of the story that is important from a management perspective is, can we identify where less advantaged groups are exposed to places with bad water quality and prioritize work that brings a decision maker to do something about it?

“This research might tell us who is benefitting from water quality improvements in Narragansett Bay, and who isn’t.”

• Hamel, K., Lacasse, K. & Dalton, T. (2021).   Recreational users' perceptions of coastal water quality in Rhode Island (USA): Implications for policy development and management  . Marine Pollution Bulletin, 172, 112810.
• Refulio-Coronado, S., Lacasse, K., Dalton, T., Humphries, A., Basu, S., Uchida, H., & Uchida, E. (2021).   Coastal and marine socio-ecological systems: a systematic review of the literature.   Frontiers in Marine Science, 8, 648006.Chicago.
• Moore, F. C., Lacasse, K., Mach, K. J., Shin, Y. A., Gross, L. J., & Beckage, B. (2022).   Determinants of emissions pathways in the coupled climate–social system  . Nature, 603(7899), 103-111.Chicago