La Union Shoreline Erosion Rate Reaches 22.4 Percent Over Four Decades
More than one-fifth of assessed shoreline areas in La Union and Ilocos Sur eroded between 1977 and 2022, according to a University of the Philippines study that warns against further coastal development.
The erosion rates drop lower in neighboring provinces across the Ilocos Region. Ilocos Norte recorded erosion across 17.7% of its assessed shoreline, while Pangasinan registered 11.1%.
Fernando Siringan Identifies Vulnerable Coastal Stretches in Region 1
Fernando Siringan of the UP Marine Science Institute presented the findings on September 22 at the Region 1 Coastal Resilience and Biodiversity Protection Forum. He singled out the coastal stretch from Bauang to Santo Tomas and Agoo in La Union as particularly prone to shoreline loss.
You should not put development there, as much as possible, and leave it alone,
Siringan said regarding areas undergoing rapidly changing shorelines.
Researchers tracked changes by comparing historical maps with Landsat satellite images. The study documents erosion trends, potential triggers, and sediment movement along coastlines in La Union, Ilocos Sur, Ilocos Norte, and Pangasinan to assist local government planning.
Shifting River Channels and Beach Quarrying Drive Coastline Loss
The study attributes the erosion to multiple overlapping factors, including shifting river channels and quarrying along beaches and rivers. Engineering works that restrict natural sediment flow, rising sea levels, land subsidence, and typhoons also contribute to the loss.
Siringan emphasized that the specific causes and severity vary significantly by location. Meanwhile, local residents and environmental groups have voiced concerns over ongoing dredging and magnetite extraction in parts of La Union and Ilocos Sur, warning that these industrial activities could accelerate shoreline destruction and harm local fisheries.
Scientific Data Combines With Community Observations for Future Planning
Siringan argued that municipal coastal development decisions must integrate scientific data and satellite observations with the lived experiences of communities that have witnessed long-term transformations in beaches, rivers, and flooding patterns.
The research team’s coastal erosion investigations began in La Union nearly three decades ago before expanding across the entire Ilocos Region. The initiative received support from the Department of Science and Technology alongside institutional partnerships with Mariano Marcos State University and Don Mariano Marcos Memorial State University. A previous 2015 study led by Siringan for the Ilocos Sur provincial government issued similar warnings that disruptive activities in vulnerable zones would further destabilize retreating shorelines.
Frequently Asked Questions About the Ilocos Region Shoreline Study
What specific methods did researchers use to track the shoreline changes?
Researchers used historical maps paired with Landsat satellite images to measure coastline movements across La Union, Ilocos Sur, Ilocos Norte, and Pangasinan from 1977 to 2022.
Which academic institutions partnered on the coastal research project?
The Department of Science and Technology supported the research alongside partner institutions Mariano Marcos State University and Don Mariano Marcos Memorial State University.
When was the latest coastal erosion data formally presented?
Fernando Siringan presented the findings on September 22 at the Region 1 Coastal Resilience and Biodiversity Protection Forum.
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