UPR study finds 75% of northern beaches show signs of erosion, fragmentation

Coastal erosion in Arecibo.

By THE STAR STAFF

Three‑quarters of the beaches evaluated along Puerto Rico’s northern coast are experiencing erosion, highlighting growing concerns about climate‑driven shoreline loss and the vulnerability of coastal communities, according to a University of Puerto Rico study.

Researchers found that 75% of the beach transects studied showed erosion, with reductions in subaerial beach width ranging from fractions of a meter to as much as 92 meters. Only 25% of transects exhibited accretion, with increases of up to 154 meters.

The findings were published this week by the U.S. Geological Survey (USGS) as an official Data Release for the project Cambios Costeros en Once Municipios de la Costa Norte de Puerto Rico (2022-2023), marking a significant federal validation of the study’s scientific rigor. The research was led by the Instituto de Investigación y Planificación Costera de Puerto Rico, part of UPR’s Graduate School of Planning.

The project, directed by Dr. Maritza Barreto Orta and Dr. Kevián Pérez Valentín in collaboration with USGS scientist Legna Torres García, was funded through a competitive $499,000 grant over two years. Using geospatial tools, the team analyzed changes in beach width and shoreline position between 2018 and 2022/2023 across 11 municipalities: Rincón, Aguadilla, Isabela, Hatillo, Arecibo, Vega Baja, Dorado, Carolina, Loíza, Río Grande and Luquillo.

The study, whose full dataset is now publicly available on the USGS official platform, also documented widespread fragmentation of beaches caused by vegetation, rocky outcrops and built infrastructure -- conditions that diminish the shoreline’s natural ability to absorb wave energy and heighten community exposure to coastal hazards. Shoreline retreat inland was identified as the most common change during the study period, typically under 15 meters, though more severe shifts were linked to winter swells and extreme erosion events.

Built structures in the coastal zone were found to directly influence beach width, reinforcing long‑standing concerns about development pressures along Puerto Rico’s shores.

Barreto Orta emphasized that the results should serve as a wake‑up call for policymakers and planners.

“Coastal erosion in Puerto Rico is ongoing, and these findings highlight the urgency of integrating scientific data into land‑use planning,” she said. “Understanding how our beaches evolve allows us to anticipate risks, protect communities and infrastructure, and design more effective adaptation strategies in the face of climate change and extreme events.”

The research team also included Graduate School of Planning alumni Samiris Suleiman, Brittany Ubiñas and David Carrión, along with undergraduate environmental sciences student Bianca Rodríguez Mestre, who contributed to geospatial data collection and analysis.